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Mustang Bio, Inc.

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FY2020 Annual Report · Mustang Bio, Inc.
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UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

FORM 10-K

☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the Fiscal Year Ended  December 31, 2020

or

☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the Transition Period from                    to                   .

Commission File No. 001-38191

MUSTANG BIO, INC.
(Exact Name of Registrant as Specified in its Charter)

Delaware
(State or Other Jurisdiction of Incorporation or Organization)

47-3828760
(I.R.S. Employer Identification No.)

377 Plantation Street
Worcester, Massachusetts 01605
(Address including zip code of principal executive offices)

(781) 652-4500
(Registrant’s telephone number, including area code)

Securities registered pursuant to Section 12(b) of the Act:

Title of each class
Common Stock, par value $0.0001 per share

Trading Symbol(s)
MBIO

Name of  each exchange on which 
registered
NASDAQ Global Market

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Yes    ◻ No   ⌧

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act. Yes    ◻ No   ⌧

Securities registered pursuant to section 12(g) of the Act: None.

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or
for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes    ⌧    No   ◻

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§ 232.405 of this
chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). Yes   ⌧   No   ◻

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, smaller reporting company, or an emerging growth company. See the
definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act:

Large accelerated filer
Non-accelerated filer
Emerging growth company

◻
☒
☒

Accelerated filer
Smaller reporting company

◻
☒

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting
standards provided pursuant to Section 13(a) of the Exchange Act.   ☒

Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control over financial reporting under
Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report. ☐

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes    ☐ No   ⌧

Class of Common Stock
Class A Common Stock, $0.0001 par value
Common Stock, $0.0001 par value

DOCUMENTS INCORPORATED BY REFERENCE

Outstanding Shares as of March 23, 2021
845,385
84,329,415

Portions of the registrant’s Proxy Statement for its 2020 Annual Meeting of Stockholders are incorporated by reference into Part III hereof.

    
    
 
 
    
 
 
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MUSTANG BIO, INC.
ANNUAL REPORT ON FORM 10-K
TABLE OF CONTENTS

PART I
Item 1.
Item 1A.
Item 1B.
Item 2.
Item 3.
Item 4.

PART II
Item 5.
Item 6.
Item 7.
Item 7A.
Item 8.
Item 9.
Item 9A.
Item 9B.

PART III
Item 10.
Item 11.
Item 12.
Item 13.
Item 14.

PART IV
Item 15.
Item 16.

Business
Risk Factors
Unresolved Staff Comments
Properties
Legal Proceedings
Mine Safety Disclosures

Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities
Reserved
Management’s Discussion and Analysis of Financial Condition and Results of Operations
Quantitative and Qualitative Disclosures About Market Risk
Financial Statements and Supplementary Data
Changes in and Disagreements with Accountants on Accounting and Financial Disclosure
Controls and Procedures
Other Information

Directors, Executive Officers and Corporate Governance
Executive Compensation
Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters
Certain Relationships and Related Transactions, and Director Independence
Principal Accountant Fees and Services

Exhibits, Financial Statement Schedules
Form 10-K Summary

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SPECIAL CAUTIONARY NOTICE REGARDING FORWARD-LOOKING STATEMENTS

Certain matters discussed in this annual report on Form 10-K (“Form 10-K”) may constitute forward-looking statements for purposes of the Securities Act of
1933, as amended (the “Securities Act”) and the Securities Exchange Act of 1934, as amended (the “Exchange Act”), and involve known and unknown risks,
uncertainties and other factors that may cause our actual results, performance or achievements to be materially different from the future results, performance or
achievements expressed or implied by such forward-looking statements. The words “anticipate,” “believe,” “estimate,” “may,” “expect” and similar expressions
are  generally  intended  to  identify  forward-looking  statements.  Our  actual  results  may  differ  materially  from  the  results  anticipated  in  these  forward-looking
statements due to a variety of factors, including, without limitation, those discussed under the captions “Risk Factors,” and elsewhere in this Form 10-K. All
written  or  oral  forward-looking  statements  attributable  to  us  are  expressly  qualified  in  their  entirety  by  these  cautionary  statements.  Such  forward-looking
statements include, but are not limited to, statements about our:

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expectations for increases or decreases in expenses;

expectations  for  the  clinical  and  pre-clinical  development,  manufacturing,  regulatory  approval,  and  commercialization  of  our  pharmaceutical  product
candidates or any other products we may acquire or in-license;

use of clinical research centers and other contractors;

expectations for incurring capital expenditures to expand our research and development and manufacturing capabilities;

expectations for generating revenue or becoming profitable on a sustained basis;

expectations or ability to enter into marketing and other partnership agreements;

expectations or ability to enter into product acquisition and in-licensing transactions;

expectations or ability to build our own commercial infrastructure to manufacture, market and sell our drug candidates;

expectations for the acceptance of our products by doctors, patients or payors;

ability to compete against other companies and research institutions;

ability to secure adequate protection for our intellectual property;

ability to attract and retain key personnel;

ability to obtain reimbursement for our products;

estimates  of  the  sufficiency  of  our  existing  cash  and  cash  equivalents  and  investments  to  finance  our  operating  requirements,  including  expectations
regarding the value and liquidity of our investments;

stock price and the volatility of the equity markets;

expected losses; and

expectations for future capital requirements.

The forward-looking statements contained in this Form 10-K reflect our views and assumptions as of the effective date of this Form 10-K. Except as required by
law, we assume no responsibility for updating any forward-looking statements.

We qualify all of our forward-looking statements by these cautionary statements.

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SUMMARY RISK FACTORS

Our business is subject to risks of which you should be aware before making an investment decision. The risks described below are a summary of the principal
risks associated with an investment in us and are not the only risks we face. You should carefully consider these risk factors, the risk factors described in Item
1A, and the other reports and documents that we have filed with the Securities and Exchange Commission (“SEC”).  

Risks Related to our Finances and Capital Requirements

● We  have  incurred  significant  losses  since  our  inception  and  anticipate  that  we  will  incur  continued  losses  for  the  foreseeable  future.  We  have  not

generated any revenue from our development stage products, and we do not know when, or if, we will generate any revenue.

● Our short operating history makes it difficult to evaluate our business and prospects.
● Our success is contingent upon raising additional capital, which efforts may fail. Even if successful, our future capital raising activities may dilute our

current stockholders, restrict our operations, cause us to relinquish proprietary rights.

Risks Pertaining to our Business Strategy, Structure and Organization

● Our future growth and success depend on our ability to successfully develop and commercialize our product candidates, which we have yet to do.
● Our growth and success depend on our acquiring or in-licensing products or product candidates and integrating such products into our business, and we

may have limited growth opportunities if we fail to do so.

● Our future success is highly dependent on the successful development of our CAR T technology and product candidates.

Risks Inherent in Drug Development and Commercialization

Preclinical development is highly speculative and carries a high failure risk.  

●
● We  may  not  receive  the  required  regulatory  approvals  for  any  of  our  product  candidates  on  our  projected  timelines,  if  at  all,  which  may  result  in

increased costs and delay our ability to generate revenue.

● We may not obtain the desired labeling claims or intended uses for product promotion, or favorable scheduling classifications, to successfully promote

●
●

our products.
If a product candidate demonstrates adverse side effects, we may need to abandon or limit the development of such product candidate.
Even  if  a  product  candidate  is  approved,  it  may  be  subject  to  various  post-marketing  requirements,  including  studies  or  clinical  trials,  and  increased
regulatory scrutiny.

● Our  competitors  may  develop  treatments  for  our  or  our  partner  companies’  products’  target  indications,  which  could  limit  our  product  candidates’

commercial opportunity and profitability.
If our products are not broadly accepted by the healthcare community, the revenues from any such product will likely be limited.

●
● Any successful products liability claim related to any of our current or future product candidates may cause us to incur substantial liability and limit the

commercialization of such products.

● Our  gene  therapy  product  candidates  are  based  on  a  novel  technology,  which  makes  it  difficult  to  predict  the  time  and  cost  of  product  candidate

development and subsequently obtaining regulatory approval.

Risks Related to Reliance on Third Parties

● We rely, and expect to continue to rely, on third parties to conduct our preclinical studies and clinical trials, and those third parties may not perform

satisfactorily, including failing to meet deadlines for the completion of such trials or complying with applicable regulatory requirements.

● We contract with third parties for the manufacture of our product candidates for preclinical and clinical testing and may also do so for commercialization,

if and when our product candidates are approved.

● We rely on clinical data and results obtained by third parties, which may prove inaccurate or unreliable.
● We may need to license certain intellectual property from third parties, and such licenses may not be available or may not be available on commercially

reasonable terms.

Risks Relating to Legislation and Regulation Affecting the Biopharmaceutical and Other Industries

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● We operate in a heavily regulated industry, and we cannot predict the impact that any future legislation or administrative or executive action may have on

our operations.

● We may be subject to anti-kickback, fraud and abuse, false claims, transparency, health information privacy and security and other healthcare laws and
regulations, which could expose us to criminal sanctions, civil penalties, contractual damages, reputational harm, administrative burdens and diminished
profits and future earnings.

● We are subject to numerous environmental, health and safety laws and regulations and could become subject to fines or penalties or incur costs that could

harm our business

Risks Pertaining to Intellectual Property and Potential Disputes with Licensors Thereof

●

If we are unable to maintain sufficient patent protection for our technology and products, our competitors could develop and commercialize products
similar or identical to ours and our ability to successfully commercialize our technology and products could be impaired.

● We depend on our licensors for the maintenance and enforcement of to maintain and enforce the intellectual property covering certain of our product

candidates.

● We or our licensors may be subject to costly and time-consuming litigation for infringement of third-party intellectual property rights or to enforce our or

our licensors’ patents.

● Any dispute with our licensors may affect our ability to develop or commercialize our product candidates.

Risks Relating to Our Control by Fortress Biotech, Inc. (“Fortress”)

●

Fortress controls a voting majority of our common stock and has the right to receive significant share grants annually, which will result in dilution of our
other stockholders and could reduce the value of our common stock.

● We have entered into certain agreements with Fortress and may have received better terms from unaffiliated third parties.

Risks Related to Conflicts of Interest

● We share certain directors with Fortress, which could create conflicts of interest between us and Fortress.

PART I

Item 1.        Business

OVERVIEW

Mustang  Bio,  Inc.  (“Mustang”,  “We”,  “Us”  or  the  “Company”)  is  a  clinical-stage  biopharmaceutical  company  focused  on  translating  today’s  medical
breakthroughs in cell and gene therapies into potential cures for hematologic cancers, solid tumors and rare genetic diseases. We aim to acquire rights to these
technologies by licensing or otherwise acquiring an ownership interest in the technologies, funding their research and development and eventually either out-
licensing or bringing the technologies to market.

Our pipeline is currently focused in three core areas: gene therapy programs for rare genetic disorders, chimeric antigen receptor (“CAR”) engineered T cell
(“CAR  T”)  therapies  for  hematologic  malignancies  and  CAR  T  therapies  for  solid  tumors.  For  each  therapy  we  have  partnered  with  world  class  research
institutions. For our gene therapy programs, we have partnered with St. Jude Children’s Research Hospital (“St. Jude”) in the development of a first-in-class ex
vivo  lentiviral  treatment  of  X-linked  severe  combined  immunodeficiency  (“XSCID”)  and  for  our  CAR  T  therapies  we  have  partnered  with  the  City  of  Hope
National Medical Center (“COH”), Fred Hutchinson Cancer Research Center (“Fred Hutch”) and Nationwide Children’s Hospital (“Nationwide”).

Gene Therapy

In partnership with St. Jude, our gene therapy program is being conducted under an exclusive license to develop a potentially curative treatment for XSCID, a
rare genetic immune system condition in which affected patients do not live beyond infancy without treatment. This first-in-class ex vivo lentiviral gene therapy
is  currently  in  two  Phase  1/2  clinical  trials  involving  two  different  autologous  cell  products:  a  multicenter  trial  of  the  MB-107  product  in  newly  diagnosed
infants sponsored by St. Jude and a single-center trial of the MB-207 product in previously transplanted patients sponsored by the National Institutes of Health
(“NIH”). In January 2021 we received approval to proceed with our Investigational New Drug (“IND”) application with the U.S. Food and Drug Administration
(“FDA”) to initiate a pivotal non-

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randomized  multicenter  Phase  2  clinical  trial  of  MB-107  in  newly  diagnosed  infants  with  XSCID  who  are  under  the  age  of  two.  We  plan  to  file  an  IND
application in the second quarter of 2021 in order to conduct a pivotal non-randomized multicenter Phase 2 clinical trial of MB-207 in previously transplanted
XSCID patients.

CAR T Therapies

Our  pipeline  of  CAR  T  therapies  is  being  developed  under  exclusive  licenses  from  several  world  class  research  institutions.  Our  strategy  is  to  license  these
technologies, support preclinical and clinical research activities by our partners and transfer the underlying technology to our cell processing facility located in
Worcester, Massachusetts, in order to conduct our own clinical trials.

We are developing CAR T therapies for hematologic malignancies in partnership with COH targeting CD123 (MB-102) and CS1 (MB-104) and with Fred Hutch
targeting CD20 (MB-106). Phase 1 clinical trials sponsored by COH for MB-102 and MB-104 and by Fred Hutch for MB-106 are underway. In the third quarter
of 2019 the FDA approved our IND application to initiate a multi-center Phase 1/2 clinical trial of MB-102, and our clinical trial began enrollment in 2020 for
the treatment of patients with blastic plasmacytoid dendritic cell neoplasm. We expect to file an IND for MB-106 in the first quarter of 2021 and to initiate our
own Phase 1/2 clinical trial shortly thereafter for the treatment of patients with non-Hodgkin lymphoma and chronic lymphocytic leukemia. We plan to file an
IND for a multicenter Phase 1/2 trial for MB-104 for the treatment of patients with multiple myeloma once COH has established a safe and effective dose.

We are also developing CAR T therapies for solid tumors in partnership with COH targeting  IL13Rα2  (MB-101),  HER2  (MB-103)  and  PSCA  (MB-105).  In
addition, we have partnered with Nationwide for the C134 oncolytic virus (MB-108) in order to enhance the activity of MB-101 for the treatment of patients with
glioblastoma  multiforme  (“GBM”).  Phase  1  clinical  trials  sponsored  by  COH  for  MB-101,  MB-103  and  MB-105  are  underway.  A  Phase  1  clinical  trial
sponsored by the University of Alabama at Birmingham (“UAB”) for MB-108 began during the third quarter of 2019 and, in the fourth quarter of 2021, we plan
to file an IND for the combination of MB-101 and MB-108 for the treatment of patients with GBM. We also plan to file INDs and initiate our own clinical trials
for MB-103 for the treatment of patients with metastatic breast cancer to brain and for MB-105 for the treatment of patients with prostate and pancreatic cancer.

To  date,  we  have  not  received  approval  for  the  sale  of  our  product  candidates  in  any  market  and,  therefore,  have  not  generated  any  product  sales  from  our
product candidates. In addition, we have incurred substantial operating losses since our inception, and expect to continue to incur significant operating losses for
the foreseeable future and may never become profitable. As of December 31, 2020, we have an accumulated deficit of $185.5 million.

We are a majority-controlled subsidiary of Fortress Biotech, Inc. (“Fortress”).

CORPORATE INFORMATION

Mustang Bio, Inc. was incorporated in Delaware on March 13, 2015. Our executive offices are located at 377 Plantation Street, Worcester, Massachusetts 01605.
Our telephone number is (781) 652-4500, and our email address is info@mustangbio.com.

Our website address is www.mustangbio.com. The information set forth on our website is not a part of this report. We will make available free of charge through
our website our annual reports on Form 10-K, quarterly reports on Form 10-Q and current reports on Form 8-K, and any amendments to these reports, as soon as
reasonably practicable after we electronically file such material with, or furnish such material to, the SEC. We are not including the information on our website
as  a  part  of,  nor  incorporating  it  by  reference  into,  this  report.  The  SEC  maintains  a  website  that  contains  annual,  quarterly,  and  current  reports,  proxy  and
information statements, and other information that issuers (including us) file electronically with the SEC. The SEC’s website address is https://www.sec.gov/.

PRODUCTS UNDER DEVELOPMENT

Gene Therapy for Rare Genetic Disorders

MB-107 and MB-207 (Ex vivo Lentiviral Therapy for X-linked Severe Combined Immunodeficiency (XSCID))

XSCID is a rare genetic immune system condition also known as bubble boy disease, in which affected patients do not live beyond infancy without treatment.

This first-in-class ex vivo lentiviral gene therapy has already been given to 24 patients in two early stage clinical trials, with highly encouraging results. Eleven
patients under the age of two years were treated at St. Jude and UCSF Benioff Children’s Hospital San Francisco,

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with  results  presented  at  the  61st  Annual  Meeting  of  the  American  Society  of  Hematology  (“ASH”)  in  December  2020  (ClinicalTrials.gov  Identifier:
NCT01512888), and thirteen patients 3 to 34 years of age were treated in a single-center trial at the NIH (ClinicalTrials.gov Identifier: NCT01306019), with
results presented at that same ASH meeting in December 2019.

The  existing  data  from  these  24  patients  are  encouraging.  In  the  initial  Phase  1/2  NIH  trial,  eight  patients  (referred  to  as  Cohort A)  were  followed  for  3  to
7  years. Among  Cohort A,  seven  patients  aged  3  to  23  years  increased  host  T  cells  chimerism  from  0-2%  to  28-93%  and  had  normal  T  cell  proliferation
response. These seven patients also normalized their IgM levels, and four of these patients were able to discontinue immunoglobulin replacement therapy. In
addition,  gradual  clinical  benefit  was  observed  in  the  clearance  of  chronic  norovirus  and  associated  abdominal  complaints,  malabsorption,  and  growth
retardation, with six of seven affected patients being cured of their disease. Five of six patients resolved their protein-losing enteropathy.

While the Cohort A results were impressive, the relatively inefficient transduction of hematopoietic stem/progenitor cells (“HSPCs”) required large quantities of
vector. This resulted in relatively low vector copy number in myeloid cells in some patients, with delayed immune cell recovery and persistent clinical disease,
especially  in  the  last  patient  treated  (patient  8).  To  address  this,  NIH  developed  a  refined  enhanced  transduction  (“ET”)  procedure  and  incorporated  two
transduction enhancers: LentiBOOST™ 1mg/mL and dimethyl prostaglandin 2 (dmPGE2; 1µM).

In addition to the Cohort A results, the NIH presentation at the 2019 ASH Annual Meeting included data from six ET patients (referred to as Cohort B) treated
from February to June 2019, including re-treatment of patient 8. Prior to undergoing gene therapy, the patients, who were aged 12 to 36 years, had significant
problems  with  donor  T  cell  infiltration  of  liver,  bone  marrow  and  kidneys  and  had  nearly  absent  B  and  NK  cells.  The  ET  procedure  achieved  much  greater
transduction efficiencies than were observed in Cohort A, with greater than 10-fold less vector, and resulted in faster immune reconstitution and more significant
clinical benefit by 3 months. As noted by the investigators, longer follow-up will be required to know if the increased vector marking using the ET regimen will
prove to be stable and safe long term.

In all NIH patients, the low-dose, nonmyeloablative busulfan pretreatment conditioning was well tolerated, and of a low enough intensity to avoid the need for
transfusions of red blood cells or platelets. No evidence of malignant transformation was observed.

Subsequent to the initiation of the NIH trial, eleven patients under two years old who had not previously undergone hematopoietic stem cell transplant (“HSCT”)
were treated with the ex-vivo gene therapy in a St. Jude/UCSF Phase 1/2 trial, resulting in highly encouraging results. Low-dose busulfan conditioning caused
non-hematologic adverse events in only two patients (mild mucositis; mucositis, hair loss), and no patients required blood product support. All 11 patients had
robust hematopoietic recovery within 3-4 weeks post cell infusion, and the nine patients who had a follow-up of greater than 3 months achieved normal-for-age
T-cell and natural killer (“NK”)-cell numbers within 3-4 months post gene therapy. Five patients were reported to have successfully discontinued intravenous
immunoglobulin  (“IVIG”)  therapy,  of  whom  3  responded  to  vaccines.  Median  vector  copy  number  (“VCN”)  at  12  months  post-gene  therapy  in  the  seven
patients  who  had  a  follow-up  of  greater  than  12  months  was  2.25  VCN/cell  (range:  1.24-3.03)  in  T  cells,  0.34  VCN/cell  (range:  0.23-1.25)  in  B  cells,  1.55
VCN/cell (range 1.27-3.39) in NK cells, and 0.08 VCN/cell (range: 0.03-0.76) in myeloid cells in peripheral blood, and 0.10 (range: 0.05-0.66) in CD34+ bone
marrow cells, respectively. With a median follow-up of 23.6 months, no evidence of malignant transformation was observed.

In a press release dated February 2, 2021, Mustang Bio provided a high-level update to the two ongoing phase 1 trials. That press release disclosed that all 11
patients enrolled on the St. Jude/USCF trial continued to do well, and 5 additional patients had been enrolled at the time of the most recent analysis in early
September 2020. At that time, follow-up for these 16 patients ranged from 3 months to 47 months. Similar to previous reports, the therapy continued to be well
tolerated in all patients, and stable vector marking was noted in all lineages, with successful engraftment of genetically-modified T-, B-, & NK-cells. All patients
cleared pre-existing infections, no new severe infections were noted, and all patients were outpatients. Finally, there was no evidence of malignant transformation
at a median follow up of 2 years.

The February 2, 2021, press release further disclosed that, of the 6 Cohort A patients who were alive at the time of the 2019 NIH data readout and who did not
undergo  repeat  therapy,  3  patients  were  able  to  discontinue  chronic  intravenous  immunoglobulin  (IVIG)  and  experienced  sustained  restoration  of  humoral
responses to immunization. The remaining 3 patients had reduced IVIG requirements. All chronic norovirus infections were resolved, and the quality of life of
all  patients  had  improved  significantly.  The  original  6  patients  in  Cohort  B  also  continued  to  do  well,  with  the  longest  follow-up  being  22  months.  Two
additional patients were successfully treated with transduction enhancers, for a total of 8 patients in Cohort B. As was the case in Cohort A, no serious adverse
events  related  to  treatment  were  reported  other  than  hematologic  related  to  low-dose  busulfan  conditioning,  and  there  was  no  evidence  of  malignant
transformation.

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CAR T Therapies for Hematologic Malignancies

MB-102 (CD123 CAR T cell Program for BPDCN, AML and high-risk MDS)

CD123  is  a  subunit  of  the  heterodimeric  interleukin-3-receptor  (“IL-3R”)  which  is  widely  expressed  on  human  hematologic  malignancies  including  blastic
plasmacytoid  dendritic  cell  neoplasm  (“BPDCN”)  and  acute  myeloid  leukemia  (“AML”).  In  addition,  CD123  can  be  found  on  the  surface  of  B  cell  acute
lymphoblastic leukemia (“B-ALL”), hairy cell leukemia, myelodysplastic syndrome (“MDS”), chronic myeloid leukemia (“CML”) and Hodgkin lymphoma.

Of  these  malignancies,  we  are  currently  investigating  CD123  as  a  target  for  adoptive  cellular  immunotherapy  in  BPDCN,  since  high  CD123  expression  is
associated with enhanced cell proliferation, increased resistance of these cells to apoptosis, and poor clinical prognosis. Depending on the early results in this
patient population, we may broaden the inclusion criteria to include AML and high-risk MDS (“hrMDS”). CD123 is overexpressed in the vast majority of cases
of AML and hrMDS and in essentially all cases of BPDCN.

Acute myeloid leukemia is a cancer of the myeloid line of blood cells characterized by rapid growth of abnormal white blood cells that accumulate in the bone
marrow. AML is the most common form of acute leukemia. Although AML is a relatively rare disease, there are approximately 20,000 new cases per year in the
U.S. and 10,000 deaths per year, accounting for approximately 1.8% of cancer deaths in the U.S. [Source: The Surveillance, Epidemiology, and End Results
(“SEER”) Program of the National Cancer Institute]. AML standard of care involves chemotherapy to induce remission followed by additional chemotherapy or
hematopoietic stem cell transplant. Allogeneic stem cell transplantation is the preferred treatment for AML following a second remission. It can lead to a 5-year
disease-free  survival  in  26%  of  patients.  Unfortunately,  however,  currently  only  about  half  of  relapsed  patients  are  able  to  achieve  a  second  remission  with
traditional chemotherapy agents. Patients who do not achieve a second remission are much less likely to benefit from transplantation and face a dismal outcome.

MDS is a heterogeneous group of malignant hematopoietic stem cell disorders characterized by dysplastic and ineffective blood cell production and a variable
risk of transformation to acute leukemia. Patients with MDS have varying reductions in the production of red blood cells, platelets, and mature granulocytes that
may also exhibit functional defects; these abnormalities often result in anemia, bleeding, and increased risk of infection. The precise incidence of de novo MDS
is  not  known;  conservative  estimates  from  cancer  databases  suggest  that  there  are  approximately  10,000  cases  diagnosed  annually  in  the  U.S.  The  actual
incidence of MDS is likely higher than that predicted by cancer databases, since the nonspecific symptoms may evade detection in early stages of the disease
and suspected cases may not undergo definitive testing (i.e., bone marrow biopsy) due to comorbidities. Investigations that have analyzed reimbursement claims
have estimated the incidence in the U.S. to be 30,000 to 40,000 new cases per year. MDS occurs most commonly in older adults, with a median age at diagnosis
in most series of ≥65 years and a male predominance.

MDS and AML lie along a disease continuum, with distinction between the two largely made based upon the percentage of myeloblasts, which are immature
cells with large nuclei, nucleoli, and a scant rim of dark blue cytoplasm, suggesting an underlying malignant hematologic disorder. In the current World Health
Organization (“WHO”) classification system, blast forms must account for less than 20% of the total cells of the bone marrow aspirate and peripheral blood in
order to meet the criteria for MDS.

MDS prognosis is often assessed using the revised International Prognostic Scoring System (“IPSS-R”), which takes into account cytogenetics, percentage of
bone marrow blasts, and the degree of anemia, thrombocytopenia, and neutropenia. This System categorizes patients into very low, low, intermediate, high, and
very high risk MDS. High risk and very high risk MDS are generally progressive in nature and can easily progress to AML. Treatment is stratified according to
medical fitness in a manner similar to that for older patients with AML. Patients who are medically fit or of intermediate fitness are generally evaluated soon
after diagnosis to determine their suitability for allogeneic hematopoietic cell transplantation. For patients who are not candidates for intensive treatment, care is
focused  on  relieving  symptoms  and  improving  the  quality  of  life  and  might  involve  lower  intensity  treatment,  for  example,  with  azacitidine,  decitabine,  or
targeted  therapy.  Patients  with  recurrent  or  refractory  higher  risk  MDS  may  be  encouraged  to  participate  in  clinical  trials.  Outside  of  a  clinical  trial,  the
management of patients with recurrent or refractory MDS is largely dependent on the patient’s prior therapy.

BPDCN is categorized by the WHO under AML. Most often, BPDCN presents with features of both lymphoma and leukemia. There is little data about BPDCN
and the only approved drug for this disease is tagraxofusp-erzs, which is indicated for the treatment of adult and pediatric patients with both treatment-naïve and
previously-treated  BPDCN.  The  average  age  at  diagnosis  is  60  to  70  years.  BPDCN  is  very  often  misdiagnosed  and  under-reported.  The  skin  is  the  most
frequently involved site of disease (80 percent of cases). However, BPDCN usually progresses with bone marrow involvement and a decrease in red blood cell,
white blood cell and platelet counts. The lymph nodes and spleen may also be involved. Common misdiagnoses for BPCDN include non-Hodgkin lymphoma
(“NHL”), AML, leukemia cutis [a nonspecific term used for cutaneous (skin) manifestation of any type of leukemia], melanoma (a type of skin cancer), and
lupus erythematosus (chronic

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inflammatory disease that occurs when the body’s immune system attacks its own tissues and organs). There are no data or randomized clinical trials that can
define the best first treatment for patients with BPDCN. In addition to the emerging use of tagraxofusp-erzs, which was approved by the FDA in December 2018,
treatment sometimes includes therapies that are used for AML, ALL, or lymphoma. The time for which a patient responds to these treatments is usually short.
After  a  relapse,  second  remissions  with  conventional  chemotherapy  are  difficult  to  achieve.  Allogeneic  hematopoietic  stem  cell  transplant  (“allo-SCT”),
especially if offered in first remission, may result in longer remissions. The current recommendation is for BPDCN patients to be evaluated for an allo-SCT as
soon as possible and to begin searching for a donor.

The use of CAR T immunotherapy in relapsed BPDCN, AML, and hrMDS patients may offer the potential to achieve a complete or longer lasting remission.
We have developed CD123-targeted CAR T cells designed to be activated, to proliferate, and to kill CD123-expressing tumor cells [Mardiros A  et al.  Blood.
2013;122(18):3138-3148].  The  therapy  is  designed  to  recognize  and  eliminate  malignant  cells,  leading  to  remission  in  patients  with  relapsed  or  refractory
BPDCN, AML, and hrMDS, and could serve as a bridge to potentially curative allogeneic stem cell transplant. The manufacturing process genetically modifies
T cells isolated from peripheral blood mononuclear cells in order to express a CD123-specific, hinge-optimized, CD28 co-stimulatory domain-expressing CAR.

In October 2020, we announced the dosing of the first patient in a multicenter Phase 1/2 clinical trial of MB-102 in patients with relapsed or refractory BPDCN
(Clinicaltrials.gov Identifier: NCT04109482). This is also the first clinical trial under a Mustang IND in which a patient was dosed with cells processed in our
manufacturing facility.  

MB-104 (CS1 CAR T for Multiple Myeloma and Light Chain Amyloidosis)

CS1 (also known as CD319, CRACC and SLAMF7) was identified as an NK cell receptor regulating immune functions. It is also expressed on B cells, T cells,
dendritic cells, NK-T cells, and monocytes. CS1 is overexpressed in multiple myeloma (“MM”)  and  light  chain  amyloidosis  (“AL”),  which  makes  it  a  good
target for immunotherapy. A humanized anti-CS1 antibody, elotuzumab (Empliciti™), has shown promising results in clinical studies. Despite great advances in
treatment, MM remains an incurable malignancy of plasma cells. AL is a protein deposition disorder that is a result of a plasma cell dysplasia, similar to MM.
Immunotherapy is an attractive approach for AL because of the low burden of disease. Our academic partners at COH have developed a novel second generation
CS1-specific CAR T cell therapy. In preclinical studies, they have demonstrated efficacy of these CAR T cells, both in vitro and in vivo, within the context of
clinically relevant models of MM and AL. COH is evaluating the safety of this CS1-specific CAR T cell therapy in a Phase 1 trial that commenced in the first
half of 2019 (ClinicalTrials.gov Identifier: NCT03710421). Once COH has established a safe and effective dose for MB-104 in this trial, we expect to file an
IND for a multicenter Phase 1/2 trial for the treatment of patients with MM.

MB-106 (CD20 CAR T cell Program for B cell non-Hodgkin lymphoma (NHL) and chronic lymphocytic leukemia (CLL))

CD20 is a promising target for immunotherapy of B-cell malignancies. CD20 is a B-cell lineage-specific phosphoprotein that is expressed in high, homogeneous
density on the surface of more than 95% of B-cell NHL and CLL. CD20 is stable on the cell surface with minimal shedding or internalization upon binding
antibody  and  is  present  at  only  nanomolar  levels  as  soluble  antigen.  It  is  well  established  as  an  effective  immunotherapy  target,  with  extensive  studies
demonstrating improved tumor responses and survival of B-NHL patients treated with rituximab and other anti-CD20 antibodies. Importantly, CD20 continues
to be expressed on the lymphoma cells of most patients with relapsed B-NHL despite repetitive rituximab treatments, and loss of CD20 expression is not a major
contributor to treatment resistance. Thus, there is strong rationale for testing CD20 CAR T cells as an immunotherapy for NHL.

More than 70,000 new cases of NHL are diagnosed each year in the United States, and more than 19,000 patients die of this group of diseases annually. Most
forms  of  NHL  including  follicular  lymphoma,  mantle  cell  lymphoma,  marginal  zone  lymphoma,  lymphoplasmacytic  lymphoma,  and  small  lymphocytic
lymphoma,  which  account  collectively  for  ~45%  of  all  cases  of  NHL,  are  incurable  with  available  therapies,  except  for  allogenic  hematopoietic  stem  cell
transplant  (“allo-SCT”).  However,  many  NHL  patients  are  not  suitable  candidates  for  allo-SCT,  and  this  treatment  is  also  limited  by  significant  rates  of
morbidity and mortality due to graft-versus-host disease. Aggressive B-cell lymphomas such as diffuse large B-cell lymphoma account for 30-35% of NHL. The
majority  of  patients  with  aggressive  B-NHL  are  successfully  treated  with  combination  chemotherapy,  but  a  significant  proportion  relapse  or  have  refractory
disease, and the outcome of these patients is poor. Innovative new treatments are therefore urgently needed.

Chronic  lymphocytic  leukemia/small  lymphocytic  lymphoma  (CLL/SLL)  is  a  mature  B  cell  neoplasm  characterized  by  a  progressive  accumulation  of
monoclonal  B  lymphocytes.  CLL  is  considered  to  be  identical  (i.e.,  one  disease  with  different  manifestations)  to  the  non-Hodgkin  lymphoma  SLL.  The
malignant cells seen in CLL and SLL have identical pathologic and immunophenotypic features. The term CLL is used when the disease manifests primarily in
the blood, whereas the term SLL is used when involvement is primarily nodal.

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CLL/SLL is the most common leukemia in adults in Western countries, accounting for approximately 25 to 35 percent of all leukemias in the United States. It is
estimated that 21,250 new cases of CLL/SLL will be diagnosed in the United States in 2021. CLL/SLL is considered to be mainly a disease of older adults, with
a median age at diagnosis of approximately 70 years; however, it is not unusual to make this diagnosis in younger individuals (e.g., from 30 to 39 years of age).
The incidence increases rapidly with increasing age. The natural history of CLL is extremely variable, with survival times from initial diagnosis that range from
approximately 2 to 20 years, and a median survival of approximately 10 years.

Most patients will have a complete or partial response to initial therapy. However, conventional therapy for CLL is not curative and most patients experience
relapse. In addition, many patients will require a change in therapy due to intolerance. Patients with CLL are generally elderly with a median age older than 70
years, and due to the relatively benign course of the disease in the majority of patients, only selected patients are candidates for intensive treatments such as
HCT. Innovative new treatments with a favorable safety profile are therefore urgently needed for patients with relapsed and refractory disease.

Fred Hutch has an open IND for a Phase 1/2 clinical study to evaluate the anti-tumor activity and safety of administering CD20 directed CAR T cells (MB-106)
to patients with relapsed or refractory B-cell NHL or chronic lymphocytic leukemia (ClinicalTrials.gov Identifier: NCT03277729). Secondary endpoints include
safety  and  toxicity,  preliminary  antitumor  activity  as  measured  by  overall  response  rate  and  complete  remission  rate,  progression-free  survival,  and  overall
survival. The trial will also assess CAR T cell persistence and determine the potential immunogenicity of the cells, and Mustang together with Fred Hutch will
determine a recommended Phase 2 dose. Fred Hutch intends to enroll approximately 30 subjects on the trial, which is being led by principal investigator Mazyar
Shadman, M.D., M.P.H., Assistant Member of Fred Hutch’s Clinical Research Division. This IND was submitted on February 24, 2017, with Fred Hutch as the
sponsor.

The IND was amended in 2019 to incorporate an optimized manufacturing process that had been developed in collaboration with Mustang. Due to the expected
increased potency of the CAR-T cells, the dose in the first cohort treated with this optimized manufacturing process was reduced back to the cohort 1 dose of 3.3
x 105  CAR  T  cells/kg.  The  first  patient  treated  in  this  cohort  had  follicular  lymphoma  that  had  relapsed  after  initial  therapy,  maintenance  therapy,  and  two
salvage regimens. She achieved a complete response (CR) on Day 28, and no cytokine release syndrome or neurologic toxicity was observed. While this initial
success using the optimized MB-106 process is important, additional clinical testing is necessary, and accrual to the trial continues.

In December 2020, at the 62nd American Society of Hematology Annual Meeting, Mustang and Fred Hutch announced interim data in patients with relapsed or
refractory B-cell NHL from the ongoing Phase 1/2 clinical trial of MB-106 at Fred Hutch. Data presented by Fred Hutch reported on an initial seven patients
treated  without  response  and  without  significant  CAR  T  cell  expansion  or  persistence. Among  these  7  patients  there  was  one  occurrence  of  cytokine  release
syndrome (CRS; grade 3 – unexplained alkaline phosphatase elevation in the setting of fever), and there were no occurrences of immune effector cell-associated
neurotoxicity syndrome (ICANS). Subsequently the trial was put on hold while Fred Hutch collaborated with Mustang to undertake a major modification in the
cell manufacturing process.

Following IND amendment to implement this modified cell processing, 9 patients – 7 with follicular lymphoma and 2 with mantle cell lymphoma – were treated
at 4 different dose levels ranging from 1 x 105 CAR T cells/kg to 3.3 x 106 CAR T cells/kg. The overall response rate was 89% (8/9), the complete response rate
was 44% (4/9), and there was good expansion and persistence of CAR T cells. All complete responses were ongoing at the time of data disclosure. One patient
experienced a grade 1 episode of CRS, and no patients experienced ICANS. Mustang plans to file an IND at the end of the first quarter of 2021 to enable the
initiation of a multicenter Phase 1/2 trial of MB-106.

CAR T Therapies for Solid Tumors

MB-101 (IL13Rα2 CAR T Cell Program for Glioblastoma)

GBM is the most common brain and central nervous system (“CNS”) cancer, accounting for 45.2% of malignant primary brain and CNS tumors, 54% of all
gliomas, and 16% of all primary brain and CNS tumors. More than 13,000 new glioblastoma cases were predicted in the U.S. for 2020. Malignant brain tumors
are the most common cause of cancer-related deaths in adolescents and young adults aged 15-39 and the most common cancer occurring among 15-19 year-olds
in the U.S. While GBM is a rare disease [(2-3 cases per 100,000 persons per year in the U.S. and European Union (“EU”)], it is quite lethal, with five-year
survival rates historically under 10%. Standard of care therapy consists of maximal surgical resection, radiation and chemotherapy with temozolomide, which,
while rarely curative, is shown to extend median overall survival from 4.5 to 15 months. GBM remains difficult to treat due to the inherent resistance of the
tumor to conventional therapies.

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Immunotherapy  approaches  targeting  brain  tumors  offer  promise  over  conventional  treatments.  IL13Rα2  is  an  attractive  target  for  CAR  T  therapy,  as  it  has
limited expression in normal tissue but is overexpressed on the surface of greater than 50% of GBM tumors. CAR T cells are designed to express membrane-
tethered IL-13 receptor ligand (“IL-13”) mutated at a single site (glutamic acid at position 13 to a tyrosine; E13Y) with high affinity for IL13Rα2 and reduced
binding to IL13Rα1 in order to reduce healthy tissue targeting (Kahlon KS et al. Cancer Research. 2004;64:9160-9166).

We are developing an optimized CAR T product incorporating enhancements in CAR T design and T cell engineering to improve antitumor potency and T cell
persistence. We include a second-generation hinge-optimized CAR containing mutations in the IgG4 linker to reduce off-target Fc interactions (Jonnalagadda M
et al. Molecular Therapy. 2015;23(4):757-768.). We also include the 4-1BB (CD137) co-stimulatory signaling domain for improved survival and maintenance of
CAR T cells. Finally, we incorporate the extracellular domain of CD19 as a selection/tracking marker. In order to further improve persistence, either central
memory T-cells (TCM; Arms  1  –  4)  or  enriched  CD62L+  naïve  and  memory  T  cells  (TN/MEM; Arm  5)  are  isolated  and  enriched.  The  manufacturing  process
limits ex vivo expansion, which is designed to reduce T cell exhaustion and maintain a TCM or TN/MEM phenotype. These CAR modified TCM and TN/MEM cells
are shown to be more potent and persistent than earlier generations of CAR T cells, based on experiments with CAR Ts in mouse xenograft models of GBM.

Our academic partners at COH have an open IND to assess the feasibility and safety of using TCM or TN/MEM  enriched  IL13Rα2-specific  CAR  engineered  T
cells  for  clinical  study  participants  with  recurrent/refractory  malignant  glioma  (ClinicalTrials.gov  Identifier:  NCT02208362).  This  IND  was  submitted  in
October 2014, with COH as the sponsor. COH has enrolled and treated 65 patients as of December 31, 2020. In the annual meeting of the American Association
for Cancer Research in April 2018, our collaborators at COH presented the preliminary data for patients enrolled on Arm 2 of the protocol (the “Intracavitary
Arm”).  The  investigators  reported  that  the  CAR  T  cells  were  well-tolerated,  meaning  that  no  dose-limiting  toxicities  had  been  seen  to  date.  In  2016  the
investigators  reported  on  a  patient  that  they  determined  had  a  complete  response  to  treatment  based  on  the  imaging  and  clinical  features  set  forth  by  the
Response Assessment in Neuro-Oncology Criteria (“RANO”). This result was published as a case report in the New England Journal of Medicine (Brown CE et
al. NEJM. 2016;375:2561-9). As described in the paper, a patient with recurrent multifocal glioblastoma received multiple infusions of IL13Rα2-specific CAR T
cells  over  220  days  through  two  intracranial  delivery  routes  –  infusions  into  the  resected  tumor  cavity  followed  by  infusions  into  the  ventricular  system.
Intracranial infusions of IL13Rα2-targeted CAR T cells were not associated with any toxic effects of grade 3 or higher. After CAR T-cell treatment, regression
of all intracranial and spinal tumors was observed, along with corresponding increases in levels of cytokines and immune cells in the cerebrospinal fluid. This
clinical response was sustained for 7.5 months after the initiation of CAR T-cell therapy; however, the patient’s disease eventually recurred at four new locations
that were distinct and non-adjacent to the original tumors, and biopsy of one of these lesions showed decreased expression of IL13Rα2. With enrollment in this
Phase 1 study nearly complete, COH has established the recommended Phase 2 dose, schedule and route of administration, as well as optimal T cell selection.
Results from this study have laid the foundation for 3 new MB-101 studies:

1. MB-101  with  or  without  nivolumab  and  ipilimumab  in  treating  patients  with  recurrent  or  refractory  glioblastoma  (currently  enrolling  patients;

ClinicalTrials.gov Identifier: NCT04003649);

2. MB-101  in  treating  patients  with  recurrent  or  refractory  glioblastoma  with  a  substantial  component  of  leptomeningeal  disease  (currently  enrolling

patients; ClinicalTrials.gov Identifier: NCT04661384);

3. MB-101 in combination with the C134 oncolytic virus (MB-108) in treating patients with recurrent or refractory glioblastoma (IND filing expected in the

fourth quarter of 2021).

MB-103 (HER2 CAR T for GBM & Metastatic Breast Cancer to Brain)

HER2/neu  (“HER2”)  is  a  growth-promoting  protein  on  the  outside  of  all  breast  cells.  Breast  cancer  cells  with  higher  than  normal  levels  of  HER2  are  called
HER2-positive (“HER2+”). These cancers tend to grow and spread faster than other breast cancers. Breast cancer is the most commonly diagnosed cancer in
women, with over 42,000 women in the United States expected to die from advanced metastatic disease in 2020. Approximately 20% to 25% of breast cancers
overexpress HER2, which is an established therapeutic target of both monoclonal antibodies (mAbs) and receptor tyrosine kinase inhibitors. With the advent of
effective mAbs directed against HER2, the median overall survival of patients with metastatic HER2+ breast cancer has improved. However, management of
metastatic disease in the brain and/or CNS – observed in up to 50% of HER2+ breast cancer patients – continues to be a clinical challenge in large part due to the
inability of mAbs to sufficiently cross the blood-brain barrier. Although small-molecule inhibitors of HER2 exist and have been clinically approved, their single-
agent  efficacy  in  the  context  of  metastatic  disease  to  the  brain  has  been  limited.  While  HER2-targeted  therapy  in  combination  with  conventional  agents  has
shown some promise for the treatment of patients with metastatic breast cancer, control of brain metastases remains a significant unmet clinical need, as most
patients  survive  less  than  two  years  following  CNS  involvement.  Recent  advances  in  cellular  immunotherapy  approaches  have  underscored  the  potential  for
potent antitumor immune responses and clinical benefit against solid cancers, and these approaches may be effective in the treatment of HER2+ cancers – in
particular breast cancer – that have metastasized to

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the brain. Likewise, HER2 has been suggested as a suitable target for GBM, wherein elevated HER2 protein levels have been correlated with impaired survival.

CAR-based T-cell immunotherapy is being actively investigated for the treatment of solid tumors, including HER2+ cancers. Our academic partners at COH
have developed a second-generation HER2-specific CAR T-cell for the treatment of brain and/or leptomeningeal metastases from HER2+ cancers, as well as for
the treatment of refractory/relapsed HER2+ GBM. COH’s preclinical data demonstrate effective targeting of breast cancer brain metastases with intraventricular
delivery of CAR T cells expressing HER2-CARs that contain the 4-1BB costimulatory domain. COH is evaluating the safety of this HER2-specific CAR T cell
therapy  in  two  Phase  1  clinical  trials  that  commenced  in  the  fourth  quarter  of  2018  (ClinicalTrials.gov  Identifier:  NCT03389230  for  HER2+  GBM;
ClinicalTrials.gov Identifier: NCT03696030 for HER2+ brain metastases).

MB-105 (PSCA CAR T for Prostate & Pancreatic Cancers)

PSCA is a glycosylphosphatidylinositol-anchored cell membrane glycoprotein. In addition to being highly expressed in the prostate it is also expressed in the
bladder, placenta, colon, kidney, and stomach. This gene is upregulated in a large proportion of prostate cancers and is also detected in cancers of the bladder and
pancreas. The gene includes a polymorphism that results in an upstream start codon in some individuals; this polymorphism is thought to be associated with a
risk for certain gastric and bladder cancers. Prostate cancer may be amenable to T cell-based immunotherapy since several tumor antigens, including prostate
stem-cell antigen (“PSCA”), are widely overexpressed in metastatic disease. Our academic partners at COH have developed a second-generation PSCA-specific
CAR T cell therapy that has demonstrated robust in vitro and in vivo anti-tumor activity in patient-derived, clinically relevant, bone-metastatic prostate cancer
xenograft models. COH is evaluating the safety of this PSCA-specific CAR T cell therapy in a Phase 1 trial treating patients with PSCA+ metastatic castration-
resistant prostate cancer (ClinicalTrials.gov Identifier: NCT03873805).

In October 2020,we announced initial data from the Phase 1 clinical trial in patients with PSCA-positive castration-resistance prostate cancer (“CRPC”). In a
presentation at the 2020 Annual Prostate Cancer Foundation Scientific Retreat, the COH principal investigator reported results from a highly refractory patient
treated with MB-105 who experienced a 94 percent reduction in prostate-specific antigen (“PSA”), near complete reduction of measurable soft tissue metastasis
by computerized tomography, and improvement in bone metastases by magnetic resonance imaging. We believe additional data could potentially be provided in
the second half of 2021.

Technology to Convert GBM from an Immunologically Cold Tumor to an Immunologically Hot Tumor

MB-108 (HSV-1 oncolytic virus C134)

C134 is a next-generation oncolytic herpes simplex virus (“oHSV”) that is conditionally replication competent; that is, it can replicate in tumor cells, but not in
normal cells, thus killing the tumor cells directly through this process. Replication of C134 in the tumor itself not only kills the infected tumor cells but causes
the tumor cell to act as a factory to produce new virus. These virus particles are released as the tumor cell dies and can then proceed to infect other tumor cells in
the vicinity and continue the process of tumor kill. In addition to this direct oncolytic activity, the virus promotes an immune response against surviving tumor
cells,  which  increases  the  antitumor  effect  of  the  therapy.  The  virus  expresses  a  gene  from  another  virus  from  the  same  overall  virus  family,  human
cytomegalovirus,  that  allows  it  to  replicate  better  in  the  tumor  cells  than  its  first-generation  predecessors.  However,  the  virus  has  also  been  genetically
engineered to minimize the production of any toxic effects for the patient receiving the therapy.

To improve this virus over its first-generation predecessors, modifications have focused on improving viral replication and spread within the tumor bed and on
enhancing  bystander  damage  to  uninfected  tumor  cells.  These  effects  cumulatively  should  result  in  converting  an  immunologically  cold  tumor  to  an
immunologically hot tumor, which Mustang anticipates will increase the efficacy of its IL13Rα2-directed CAR T for the treatment of GBM.

UAB is the clinical trial site for the Phase 1 trial of MB-108, and the site has initiated a Phase 1 trial that began enrolling patients in 2019 (ClinicalTrials.gov
Identifier:  NCT03657576).  The  primary  objective  of  this  study  is  to  determine  the  safety  and  tolerability  of  stereotactic  intracerebral  injections  of  escalating
doses of MB-108 and to determine the maximally tolerated dose (“MTD”) of the oncolytic virus. Secondary objectives are to obtain preliminary information
about the potential benefit of MB-108 in the treatment of patients with recurrent malignant gliomas, including relevant data on markers of efficacy, including
time to tumor progression and patient survival. In 2021, we intend to combine MB-108 with MB-101 to potentially enhance efficacy in treating GBM. This trial
has been on clinical hold since October 2020 due to toxicity at the highest dose level, and UAB expects FDA clearance in the first half of 2021 in order to resume
enrolling patients at a lower dose level. As a result of this clinical hold, as well as COVID-19 virus-related accrual delays in 2020, we expect that IND filing for
the combination trial of MB-108 with MB-101 will be delayed until the fourth quarter of 2021.

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INTELLECTUAL PROPERTY AND PATENTS

General

Our goal is to obtain, maintain and enforce patent protection for our products, formulations, processes, methods and other proprietary technologies, preserve our
trade secrets, and operate without infringing on the proprietary rights of other parties, both in the U.S. and in other countries. Our policy is to actively seek to
obtain, where appropriate, the broad intellectual property protection for our product candidates, proprietary information and proprietary technology through a
combination of contractual arrangements and patents, both in the U.S. and elsewhere in the world.

We  also  depend  upon  the  skills,  knowledge  and  experience  of  our  scientific  and  technical  personnel,  as  well  as  that  of  our  advisors,  consultants  and  other
contractors (“know-how”). To help protect our proprietary know-how which is not patentable, and for inventions for which patents may be difficult to enforce,
we rely on trade secret protection and confidentiality agreements to protect our interests. To this end, we require all employees, consultants, advisors and other
contractors  to  enter  into  confidentiality  agreements  which  prohibit  the  disclosure  of  confidential  information  and,  where  applicable,  require  disclosure  and
assignment to us of the ideas, developments, discoveries and inventions that they generate or make, and which are important to our business.

Patents and other proprietary rights are crucial to the development of our business. We will be able to protect our proprietary technologies from unauthorized
use  by  third  parties  only  to  the  extent  that  our  proprietary  rights  are  covered  by  valid  and  enforceable  patents,  supported  by  regulatory  exclusivity  or  are
effectively maintained as trade secrets. We have a few patents and patent applications related to our compounds and other technology, but we cannot guarantee
the scope of protection of the issued patents, or that such patents will survive a validity or enforceability challenge, or that any of the pending patent applications
will issue as patents.

Generally, patent applications in the U.S. are maintained in secrecy for a period of 18 months or more. There is even an opportunity under specific circumstances
to  keep  the  contents  of  patent  applications  hidden  until  the  patent  application  matures  to  an  issued  patent.  The  patent  positions  of  biotechnology  and
pharmaceutical companies are highly uncertain and involve complex legal and factual questions. Therefore, we cannot predict the breadth of claims allowed in
biotechnology  and  pharmaceutical  patents,  or  their  enforceability.  To  date,  there  has  been  no  consistent  policy  regarding  the  breadth  of  claims  allowed  in
biotechnology patents. Third parties or competitors may challenge or circumvent our patents or patent applications, if issued. If our competitors prepare and file
patent applications in the U.S. that claim technology also claimed by us, we may have to participate in interference or derivation proceedings declared by the
U.S. Patent and Trademark Office (“USPTO”) to determine priority of invention, which could result in substantial cost, even if the eventual outcome is favorable
to us. Because of the extensive time required for development, testing and regulatory review of a potential product, it is possible that before we commercialize
any of our products, any related patent may expire or remain in existence for only a short period following commercialization, thus reducing any advantage of
the patent. However, the life of a patent covering a product that has been subject to regulatory approval may have the ability to be extended through the patent
restoration program, although any such extension could still be minimal. Additionally, statutory caps impose further limitation on any such extensions.

If  a  patent  is  issued  to  a  third  party  containing  one  or  more  preclusive  or  conflicting  claims,  and  those  claims  are  ultimately  determined  to  be  valid  and
enforceable,  we  may  be  required  to  obtain  a  license,  if  available,  under  such  patent  or  to  develop  or  obtain  alternative  technology.  In  the  event  of  litigation
involving a third-party claim, an adverse outcome in the litigation could subject us to significant liabilities to such third party, require us to seek a license for the
disputed rights from such third party, and/or require us to cease use of the technology. Further, our breach of an existing license or failure to obtain a license to
technology required to commercialize our products may seriously harm our business. We also may need to commence litigation to enforce any patents issued to
us or to determine the scope and validity of third-party proprietary rights. Litigation would not only involve substantial costs but would also involve substantial
time commitments on the part of our key executives and research and development personnel.

In March 2015, we licensed intellectual property related to CAR T technology from COH. The intellectual property licensed thereunder includes two granted
U.S. patents and pending patent applications in a number of countries, including the U.S. and the EU, as well as pending patent applications in Japan, China,
South  Korea,  Australia  and  the  developing  world.  These  granted  patents  include  claims  directed  to  nucleic  acids  and  expression  vectors  encoding  CARs
targeting IL13Rα2 and CD123. The granted patents and any patents maturing from these pending applications will expire no sooner than October 2033. The
pending applications in these patent families also include various claims relating to CARs, T cells that express the CARs, methods of treatment utilizing the
CAR  T  cells  and  additional  specific  features  to  optimize  administration  of  CAR  T  cells,  targeting,  binding  specificity,  cell  stimulation  and  persistence.
Additional applications and pending claims from COH that we have rights to include the use of an optimized hinge region for many targeted CAR constructions,
along with compositions and methods to isolate and transfect T memory cells to improve cellular persistence, as well as applications and claims related to CS1-,
HER2-, and PSCA-targeted CARs.

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Also, in March 2015, we executed a sponsored research agreement with COH, pursuant to which research is performed in the laboratory of Drs. Stephen Forman
and Christine Brown. The sponsored research agreement gives us the right to first negotiation under specified maximum terms regarding any future inventions
arising from the laboratory.

In  May  2017,  we  licensed  intellectual  property  related  to  CAR  T  technology  for  targeting  CD20  from  Fred  Hutch.  The  intellectual  property  includes  an
international application under the Patent Cooperation Treaty (i.e., a PCT application), which has now entered the national stage of multiple countries including
the U.S., EU, Japan, China, and Canada, among others. These applications contain claims relating to various CD20-targeting CAR constructs and CAR T cells,
as  well  as  methods  of  making  and  using  the  same.  In  May  2018,  national  stage  applications  claiming  priority  to  the  PCT  application  were  filed  in  several
jurisdictions around the world, including the U.S. and Europe, in order to begin substantive examination of the claims. Patents maturing from these national stage
applications will expire no sooner than March 2037.

In March 2017, we licensed intellectual property related to antibodies and binding agents that specifically bind to PSCA from the University of California Los
Angeles (“UCLA”). The intellectual property includes multiple granted patents and pending applications from around the world including the U.S., EU, Japan,
China, and Canada. The granted patents and patents maturing from the pending applications will expire no sooner than March 2027.

In August  2018,  we  licensed  from  St.  Jude  Children’s  Research  Hospital  XSCID  Technology  related  to  an ex vivo  lentiviral  vector  gene  therapy  program  to
provide a normal copy of the IL2RG gene to patients born with XSCID.

In February 2019, we licensed Material and Technical Information related to the HSV-1 oncolytic virus C134 from Nationwide in Columbus, Ohio.

In August 2019, we licensed from CSL Behring (Calimmune) the CytegrityTM stable producer cell line developed and used by St. Jude. The CytegrityTM stable
producer cell line will be used to produce the viral vector for MB-107.

In September 2020, we entered into an exclusive, worldwide licensing agreement with SIRION Biotech for the rights to SIRION’s LentiBOOSTTM technology
for the development of MB-207.

In addition to the technology the company has in-licensed, Mustang has also developed its own proprietary intellectual property, both alone and in conjunction
with COH. In particular, Mustang filed a U.S. provisional application directed to optimized methods for manufacturing cell-based therapeutics, and Mustang and
COH, as co-applicants, filed a U.S. provisional application directed to methods of treating hematological cancers.

Other Intellectual Property Rights

We depend upon trademarks, trade secrets, knowhow and continuing technological advances to develop and maintain our competitive position. To maintain the
confidentiality of trade secrets and proprietary information, we require our employees, scientific advisors, consultants and collaborators, upon commencement of
a relationship with us, to execute confidentiality agreements and, in the case of parties other than our research and development collaborators, to agree to assign
their inventions to us. These agreements are designed to protect our proprietary information and to grant us ownership of technologies that are developed in
connection with their relationship with us. These agreements may not, however, provide protection for our trade secrets in the event of unauthorized disclosure
of such information.

In  addition  to  patent  protection,  we  may  utilize  orphan  drug  regulations  or  other  provisions  of  the  Food,  Drug  and  Cosmetic Act  of  1938,  as  amended  (the
“FDCA”), to provide market exclusivity for certain of our product candidates. Orphan drug regulations provide incentives to pharmaceutical and biotechnology
companies to develop and manufacture drugs for the treatment of rare diseases, currently defined as diseases that exist in fewer than 200,000 individuals in the
U.S., or diseases that affect more than 200,000 individuals in the U.S. but for which the sponsor does not realistically anticipate will generate a net profit. Under
these provisions, a manufacturer of a designated orphan drug can seek tax benefits, and the holder of the first approval of a designated orphan product from the
FDA will be granted a seven-year period of marketing exclusivity for such FDA approved orphan product.

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LICENSE, CLINICAL TRIAL AND SPONSORED RESEARCH AGREEMENTS

St. Jude Children’s Research Hospital

XSCID License

On August 2, 2018, the Company entered into an exclusive worldwide license agreement with St. Jude for the development of a first-in-class ex vivo lentiviral
gene therapy for the treatment of XSCID. The Company paid $1.0 million in consideration for the exclusive license in addition to an annual maintenance fee of
$0.1  million  (beginning  in  2019).  St.  Jude  is  eligible  to  receive  payments  totaling  $13.5  million  upon  the  achievement  of  five  development  and
commercialization milestones. Royalty payments in the mid-single digits are due on net sales of licensed products.

XSCID Non-interventional Services Agreement

In  December  2019,  the  Company  entered  into  a  Non-Interventional  Services Agreement  with  Children's  CGMP,  LLC  ("Children’s"),  an  affiliate  of  St.  Jude
Children's  Research  Hospital,  pursuant  to  which  Children’s  provides  lentiviral  vector  for  non-clinical  XSCID  research  purposes,  as  well  as  related  advisory
services. Pursuant to the agreement, we agreed to fund approximately $0.8 million upon execution of the agreement.

XSCID Data Transfer Agreement

In June 2020, the Company entered into a Data Transfer Agreement for the XSCID program (the “XSCID DTA”). Pursuant to the terms of the XSCID DTA, we
made an upfront payment of approximately $1.1 million and will reimburse St. Jude for additional costs in connection with the on-going investigator-initiated
study.

City of Hope

In February 2017, the Company and COH amended and restated their license agreement, dated March 17, 2015 (the “Original Agreement”), by entering into
three separate amended and restated exclusive license agreements, one relating to the CD123-directed CAR T program, one relating to the IL13Rα2-directed
CAR T program, and one relating to the Spacer technology (described below). The total potential consideration payable to COH by the Company, in equity or
cash, did not in the aggregate change materially from the Original Agreement. As of December 31, 2020, COH owns 845,385 shares of Class A common stock
and  448,203  shares  of  common  stock,  representing  approximately  1.8%  of  ownership,  and  has  the  right  to  appoint  a  director  to  the  Board  of  Directors  (the
“Board”). The Company considers COH to be a related party, due to the foregoing rights and ownership, as well as the high proportion of the Company’s assets
that are licensed from COH.

In addition, the Company entered into a sponsored research agreement with COH under which the Company has funded continued research in the amount of
$2.0 million per year, payable in four equal installments, through the first quarter of 2020. The research covered under this arrangement is for the IL13Rα2-
directed CAR T program, the CD123-directed CAR T program, and the Spacer technology.

CD123 License

In February 2017, the Company entered into an Amended and Restated Exclusive License Agreement with COH to acquire intellectual property rights pertaining
to patent rights related to the CD123-directed CAR T program (the “CD123 License”). Pursuant to the CD123 License, the Company and COH acknowledged
that  an  upfront  fee  had  already  been  paid  under  the  Original Agreement.  In  addition,  COH  is  eligible  to  receive  an  annual  maintenance  fee  of  $25,000  and
milestone payments totaling up to approximately $14.5 million, upon and subject to the achievement of certain milestones. Royalty payments in the mid-single
digits are due on net sales of licensed products. The Company is obligated to pay COH a percentage of certain revenues received in connection with a sublicense
ranging from the mid-teens to mid-thirties, depending on the timing of the sublicense in the development of any product. In addition, equity grants made under
the Original Agreement were acknowledged, and the anti-dilution provisions of the Original Agreement were carried forward.

CD123 CRA (AML and BPDCN)

In February 2017, the Company entered into a Clinical Research Support Agreement for CD123-directed CAR T program (the “CD123 CRA”). Pursuant to the
terms of the CD123 CRA, the Company made an upfront payment of approximately $19,000 and will contribute an

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additional  $97,000  per  patient  in  connection  with  the  on-going  investigator-initiated  study.  Further,  the  Company  agreed  to  fund  approximately  $76,000
annually pertaining to the clinical development of the CD123-directed CAR T therapy.

IL13Rα2 License

In February 2017, the Company entered into an Amended and Restated Exclusive License Agreement with COH to acquire intellectual property rights pertaining
to  patent  rights  related  to  the  IL13Rα2-directed  CAR  T  program  (the  “IL13Rα2  License”).  Pursuant  to  the  IL13Rα2  License,  the  Company  and  COH
acknowledged that an upfront fee had already been paid under the Original Agreement. In addition, COH is eligible to receive an annual maintenance fee of
$25,000 and milestone payments totaling up to approximately $14.5 million, upon and subject to the achievement of certain milestones. Royalty payments in the
mid-single digits are due on net sales of licensed products. The Company is obligated to pay COH a percentage of certain revenues received in connection with a
sublicense ranging from the mid-teens to mid-thirties, depending on the timing of the sublicense in the development of any product. In addition, equity grants
made under the Original Agreement were acknowledged, and the anti-dilution provisions of the Original Agreement were carried forward.

IL13Rα2 CRA (Glioblastoma)

In February 2017, the Company entered into a Clinical Research Support Agreement for the IL13Rα2-directed CAR T program (the “IL13Rα2 GBM CRA”).
Pursuant to the terms of the IL13Rα2 CRA, the Company made an upfront payment of approximately $9,000 and will contribute an additional $140,000 per
patient  in  connection  with  the  on-going  investigator-initiated  study.  Further,  the  Company  agreed  to  fund  approximately  $66,000  annually  pertaining  to  the
clinical development of the IL13Rα2-directed CAR T therapy.

IL13Rα2 CRA (Leptomeningeal Glioblastoma)

In  October  2020,  the  Company  entered  into  a  Clinical  Research  Support  Agreement  for  the  IL13Rα2-directed  CAR  T  program  for  adult  patients  with
leptomeningeal glioblastoma, ependymoma or medulloblastoma (the “IL13Rα2 Leptomeningeal CRA”). Pursuant to the terms of the IL13Rα2 Leptomeningeal
CRA, the Company made an upfront payment of approximately $29,000 and will contribute an additional $150,000 per patient in connection with the on-going
investigator-initiated  study.  Further,  the  Company  agreed  to  fund  approximately  $200,000  annually  pertaining  to  the  clinical  development  of  the  IL13Rα2-
directed CAR T therapy.

Sponsored Research Agreement - IL13Rα2 and C134 Combination

In October 2020, the Company entered into a Sponsored Research Agreement (“SRA”) with COH to conduct combination studies of a potential IL13Rα2 CAR
and C134 oncolytic virus therapy. Pursuant to the SRA, the Company will fund research in the amount of $0.3 million for the program, with an initial term of six
months.

Spacer License

In February 2017, the Company entered into an Amended and Restated Exclusive License Agreement with COH to acquire intellectual property rights pertaining
to patent rights related to Spacer (the “Spacer License”). Pursuant to the Spacer License, the Company and COH acknowledged that an upfront fee had already
been paid under the Original Agreement. In addition, COH will receive an annual maintenance fee of $10,000. No royalties are due if the Spacer technology is
used in conjunction with a CD123 CAR or an IL13Rα2 CAR, and royalty payments in the low single digits are due on net sales of licensed products if the Spacer
technology  is  used  in  conjunction  with  other  intellectual  property.  The  Company  is  obligated  to  pay  COH  a  percentage  of  certain  revenues  received  in
connection with a sublicense in the mid-thirties, but no such payments are due in connection with sublicenses that are granted in conjunction with the sublicense
of other CARs that are licensed from COH to the Company. In addition, equity grants made under the Original Agreement were acknowledged, and the anti-
dilution provisions of the Original Agreement were carried forward.

IV/ICV License

In February 2017, the Company entered into an exclusive license agreement (the “IV/ICV License”) with COH to acquire intellectual property rights in patent
applications  related  to  the  intraventricular  and  intracerebroventricular  methods  of  delivering  T  cells  that  express  CARs.  Pursuant  to  the  IV/ICV  License,  in
March 2017, the Company paid COH an upfront fee of $0.1 million. COH is eligible to receive a milestone payment totaling approximately $0.1 million, upon
and  subject  to  the  achievement  of  a  milestone,  and  an  annual  maintenance  fee.  Royalty  payments  in  the  low  single  digits  are  due  on  net  sales  of  licensed
products.  The  Company  is  obligated  to  pay  COH  a  percentage  of  certain  revenues  received  in  connection  with  a  sublicense  in  the  mid-thirties,  but  no  such
payments are due in connection with sublicenses that are granted in conjunction with the sublicense of other CAR T programs that are licensed from COH to the
Company.

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HER2 Technology License

On  May  31,  2017,  the  Company  entered  into  an  exclusive  license  agreement  (the  “HER2 Agreement”)  with  COH  for  the  use  of  HER2  CAR  T  technology
(“HER2 Technology”), which is currently being applied in the treatment of glioblastoma multiforme and in the treatment of HER2+ cancers – in particular breast
cancer  –  that  have  metastasized  to  the  brain.  Pursuant  to  the  HER2  Agreement,  the  Company  paid  an  upfront  fee  of  $0.6  million  and  owes  an  annual
maintenance fee of $50,000 (which began in 2019). In addition, COH is eligible to receive milestone payments totaling up to $14.9 million, upon and subject to
the achievement of certain milestones. Royalty payments in the mid-single digits are due on net sales of licensed products. The Company is obligated to pay
COH  a  percentage  of  certain  revenues  received  in  connection  with  a  sublicense  ranging  from  the  mid-teens  to  mid-thirties,  depending  on  the  timing  of  the
sublicense in the development of any product.

HER2 CRA (HER2+ glioblastoma and HER2+ brain metastases)

In September 2020, the Company entered into a Clinical Research Support Agreement for the HER2-directed CAR T program (the “HER2 CRA”). Pursuant to
the  terms  of  the  HER2  CRA,  the  Company  made  an  upfront  payment  of  approximately  $29,000  and  will  contribute  an  additional  $150,000  per  patient  in
connection  with  the  on-going  investigator-initiated  study.  Further,  the  Company  agreed  to  fund  approximately  $200,000  annually  pertaining  to  the  clinical
development of the HER2-directed CAR T therapy.

CS1 Technology License

On May 31, 2017, the Company entered into an exclusive license agreement (the “CS1 Agreement”) with COH for the use of CS1-specific CAR T technology
(“CS1 Technology”), which is currently being applied in the treatment of multiple myeloma. Pursuant to the CS1 Agreement, the Company paid an upfront fee
of $0.6 million and owes an annual maintenance fee of $50,000 (which began in 2019). In addition, COH is eligible to receive milestone payments totaling up to
$14.9 million, upon and subject to the achievement of certain milestones. Royalty payments in the mid-single digits are due on net sales of licensed products. The
Company  is  obligated  to  pay  COH  a  percentage  of  certain  revenues  received  in  connection  with  a  sublicense  ranging  from  the  mid-teens  to  mid-thirties,
depending on the timing of the sublicense in the development of any product.

CS1 CRA (multiple myeloma)

In June 2020, the Company entered into a Clinical Research Support Agreement for the CS1-directed CAR T program (the “CS1 CRA”). Pursuant to the terms of
the CS1 CRA, the Company made an upfront payment of approximately $32,000 and will contribute an additional $130,000 per patient in connection with the
on-going investigator-initiated study. Further, the Company agreed to fund approximately $200,000 annually pertaining to the clinical development of the CS1-
directed CAR T therapy.

PSCA Technology License

On  May  31,  2017,  the  Company  entered  into  an  exclusive  license  agreement  (the  “PSCA Agreement”)  with  COH  for  the  use  of  PSCA  CAR  T  technology
(“PSCA  Technology”),  which  is  currently  being  applied  in  the  treatment  of  PSCA+  metastatic  castration-resistant  prostate  cancer.  Pursuant  to  the  PSCA
Agreement,  the  Company  paid  an  upfront  fee  of  $0.3  million  and  owes  an  annual  maintenance  fee  of  $50,000  (which  began  in  2019).  In  addition,  COH  is
eligible to receive milestone payments totaling up to $14.9 million, upon and subject to the achievement of certain milestones. Royalty payments in the mid-
single digits are due on net sales of licensed products. The Company is obligated to pay COH a percentage of certain revenues received in connection with a
sublicense ranging from the mid-teens to mid-thirties, depending on the timing of the sublicense in the development of any product.

PSCA CRA

In October 2020, the Company entered into a Clinical Research Support Agreement for the PSCA-directed CAR T program (the “PSCA CRA”). Pursuant to the
terms of the PSCA CRA, the Company made an upfront payment of $33,000 and will contribute an additional $125,000 per patient in connection with the on-
going investigator-initiated study. Further, the Company agreed to fund approximately $200,000 annually pertaining to the clinical development of the PSCA-
directed CAR T therapy.

Manufacturing License

On  January  3,  2018,  the  Company  entered  into  a  non-exclusive  license  agreement  with  COH  to  acquire  patent  and  licensed  know-how  rights  related  to
developing, manufacturing, and commercializing licensed products. The Company paid $75,000 in consideration for the licenses

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to  the  patent  rights  and  the  licensed  know-how  in  addition  to  an  annual  maintenance  fee.  Royalty  payments  in  the  low-single  digits  are  due  on  net  sales  of
licensed products.

Sponsored Research Agreement - Manufacturing

On  January  3,  2018,  the  Company  entered  into  an  SRA  with  COH  to  optimize  and  develop  CAR  T  cell  processing  procedures.  Pursuant  to  the  SRA,  the
Company funded continued research in the amount of $0.9 million for the program, with an initial term of two (2) years. The SRA expired in January 2020.

University of California License

On March 17, 2017, the Company entered into an exclusive license agreement with the Regents of UCLA (the “UCLA License”) to acquire intellectual property
rights  in  patent  applications  related  to  the  engineered  anti-prostate  stem  cell  antigen  antibodies  for  cancer  targeting  and  detection.  Pursuant  to  the  UCLA
License, the Company paid UCLA the upfront fee of $0.2 million and owes an annual maintenance fee of $15,000 for the first two years, $25,000 for years
three and four, and $50,000 per year thereafter. In addition, UCLA is eligible to receive milestone payments totaling up to $14.3 million, upon and subject to the
achievement of certain milestones. Royalty payments in the mid-single digits are due on net sales of licensed products.

Fred Hutchinson Cancer Research Center

CD20 Technology License

Effective July 3, 2017, Mustang entered into an exclusive, worldwide licensing agreement with Fred Hutch for the use of a CAR T therapy related to autologous
T  cells  engineered  to  express  a  CD20-specific  chimeric  antigen  receptor  (the  “CD20  Technology  License”).  Pursuant  to  the  CD20  Technology  License,  the
Company  paid  Fred  Hutch  an  upfront  fee  of  $0.3  million  and  owes  an  annual  maintenance  fee  of  $50,000  on  each  anniversary  of  the  license  until  the
achievement by the Company of regulatory approval of a licensed product using the CD20 Technology. Additional payments are due for the achievement of
eleven development milestones totaling $39.1 million. Royalty payments in the mid-single digits are due on net sales of licensed products.

CD20 CTA (NHL and CLL)

Also, on July 3, 2017, in conjunction with the CD20 Technology License from Fred Hutch, Mustang entered into an investigator-initiated clinical trial agreement
(the “CD20 CTA”) to provide partial funding for a Phase 1/2 clinical trial at Fred Hutch evaluating the safety and efficacy of the CD20 Technology in patients
with relapsed or refractory B-cell non-Hodgkin lymphomas (“NHLs”). In connection with the CD20 CTA, the Company agreed to fund up to $5.3 million of
costs associated with the clinical trial, which commenced during the fourth quarter of 2017.

In November 2020, the CD20 CTA was amended to include additional funding of approximately $0.8 million for the treatment of five patients with chronic
lymphocytic leukemia (“CLL”).

Sponsored Research Agreement

On March 17, 2018, the Company entered into an SRA with Fred Hutch related to developing and optimizing processes and systems associated with CD20 cell
processing.  Pursuant  to  the  SRA,  the  Company  funded  continued  research  in  the  amount  of  $0.6  million  during  the  term  of  the  SRA,  which  expired  in
March 2019.

Nationwide Children’s Hospital License

On February 20, 2019, the Company entered into an exclusive worldwide license agreement with Nationwide for the development of an oncolytic virus (referred
to  by  Nationwide  as  C134;  now  referred  to  by  the  Company  as  MB-108)  for  the  treatment  of  glioblastoma  multiforme.  The  Company  paid  $0.2  million  in
consideration for the exclusive license. Nationwide is eligible to receive additional payments totaling $77.5 million upon the achievement of ten development
and commercialization milestones. Royalty payments in the low-single digits are due on net sales of licensed products.

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CSL Behring (Calimmune) License

On August 23, 2019, the Company entered into a non-exclusive license agreement with CSL Behring (Calimmune) for the CytegrityTM stable producer cell line
for the production of lentiviral gene therapy for the XSCID gene therapy program. The CytegritTM stable producer cell line will be used to produce the viral
vector for Mustang’s MB-107 and MB-207 lentiviral gene therapies for the treatment of XSCID. The Company paid $0.2 million in consideration for the license.
CSL Behring (Calimmune) is eligible to receive additional payments totaling $1.2 million upon the achievement of three development and commercialization
milestones. Royalty payments in the low-single digits are due on net sales of licensed products.

SIRION Biotech License

On October 6, 2020, the Company announced a licensing agreement under which we acquired technology rights from SIRION Biotech GmbH (“SIRION”) for
LentiBOOST™  technology  for  the  development  of  MB-207,  Mustang’s  lentiviral  gene  therapy  for  the  treatment  of  patients  with  XSCID,  who  have  been
previously treated with a hematopoietic stem cell transplantation (“HSCT”) and for whom re-treatment is indicated. LentiBOOST™ is SIRION’s proprietary
non-cytotoxic transduction enhancer for lentiviral vectors.

Under the terms of the agreement, SIRION will receive an undisclosed upfront payment and development and sales milestones, as well as royalties on future
product sales.

Minaris Regenerative Medicine Agreement

On November 23, 2020, we announced an agreement with Minaris Regenerative Medicine GmbH (“Minaris”) to enable technology transfer and GMP clinical
manufacturing in Europe of our MB-107 lentiviral gene therapy program for the treatment of XSCID. Under the terms of the agreement, Minaris will perform
technology transfer of the manufacturing and analytical processes, as well as their adoption to the European regulatory environment, for the GMP-compliant
manufacturing of the drug product at its site in Ottobrunn, Germany, with the goal of supplying clinical trials in Europe.

COMPETITION

Competition in the pharmaceutical and biotechnology industries is intense. Our competitors include pharmaceutical companies and biotechnology companies, as
well  as  universities  and  public  and  private  research  institutions.  In  addition,  companies  that  are  active  in  different  but  related  fields  represent  substantial
competition  for  us.  Many  of  our  competitors  have  significantly  greater  capital  resources,  larger  research  and  development  staffs  and  facilities  and  greater
experience in drug development, regulation, manufacturing and marketing than we do. These organizations also compete with us to recruit qualified personnel,
attract partners for joint ventures or other collaborations, and license technologies that are competitive with ours. To compete successfully in this industry, we
must identify novel and unique drugs or methods of treatment and then complete the development of those drugs as treatments in advance of our competitors.

The drugs that we are attempting to develop will have to compete with existing therapies. In addition, a large number of companies are pursuing the development
of pharmaceuticals that target the same conditions that we are targeting. Other companies have products or product candidates in various stages of pre-clinical or
clinical development, or with marketing approvals, to treat conditions for which we are also seeking to discover and develop product candidates. Some of these
potential competing drugs are further advanced in development than our product candidates and may be commercialized earlier.

The field of CAR T therapy is extremely active. Companies and partnerships currently engaged in clinical trials with CAR T modalities include Bristol Myers
Squibb, Novartis Pharmaceuticals/University of Pennsylvania, bluebird bio, Allogene Therapeutics, Cellectis, Gilead Sciences, Bellicum Pharmaceuticals, MD
Anderson/Ziopharm Oncology, Atara Biotherapeutics, Celyad, Autolus Therapeutics, Precigen and Precision BioSciences.

The gene therapy field is characterized by rapidly changing technologies, significant competition and a strong emphasis on intellectual property. We are aware of
companies  currently  engaged  in  developing  gene  therapies  in  various  indications,  including  Abeona  Therapeutics,  Adverum  Biotechnologies,  Astellas,
AVROBIO, Axovant Sciences, Biogen, bluebird bio, BioMarin Pharmaceutical, Homology Medicines, Krystal Biotech, MeiraGTx, Novartis Pharmaceuticals,
Orchard Therapeutics, Passage Bio, Prevail Therapeutics, REGENXBIO, Rocket Pharmaceuticals, Roche, Sangamo Therapeutics, Sarepta Therapeutics, Solid
Biosciences,  Ultragenyx  Pharmaceuticals,  uniQure  and  Voyager  Therapeutics,  as  well  as  several  companies  addressing  other  methods  for  delivering  or
modifying genes and regulating gene expression.

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EMPLOYEES

As of December 31, 2020, we had sixty-two full and part-time employees. None of our employees are represented by a labor union or covered under a collective
bargaining  agreement  and  we  consider  our  employee  relations  to  be  good.  Employees  of  Fortress  also  make  valuable  financial,  legal,  scientific  and  other
strategic contributions to Mustang on a regular basis.

SUPPLY AND MANUFACTURING

As  an  early  stage  development  company,  we  rely  on  our  research  partners  to  manufacture  or  have  manufactured  all  lentiviral  vectors  used  in  the  clinical
development programs currently in progress at COH, Fred Hutch, St. Jude, the NIH, and UAB under the IND applications filed by these institutions. UAB is the
clinical trial site for the Phase 1 trial of Nationwide’s C134 oncolytic virus (MB-108). We will continue to rely on our research partners to manufacture lentiviral
vectors for Mustang-IND trials until such time as material is available from our contract manufacturing organizations.

Pursuant  to  the  March  2015  Licensing  Agreement  with  COH,  we  have  the  right  to  make  and  have  made  the  cellular  products,  and  we  have  negotiated
Investigator-Initiated Clinical Research Support Agreements with COH and Fred Hutch which specify the cell processing costs and numbers of patients which
will be supplied under filed protocols. Our research partners have extensive experience manufacturing clinical materials for development studies, but we are
currently dependent on both their capacity limitations and continued operating success to manufacture viral vector and to process cells for all CAR T clinical
trials for which these partners hold the INDs, as well as to have manufactured oncolytic virus for the MB-108 investigator-IND clinical trial being conducted at
UAB.

We  have  limited  experience  in  processing  cells  for  clinical  or  commercial  purposes.  In  2018  we  opened  our  own  cell  processing  facility  in  Worcester,
Massachusetts, in order to manufacture and supply cellular product candidates for all clinical trials that will be conducted under IND applications to be filed by
us. In August 2019, the FDA approved our IND application to initiate a multi-center Phase 1/2 clinical trial of MB-102 (CD123 CAR T) and in January 2021,
the  FDA  approved  our  IND  application  to  initiate  a  multi-center  Phase  2  clinical  trial  of  MB-107  (XSCID). As  with  any  supply  program,  obtaining  raw
materials of the correct quality cannot be guaranteed, and we cannot ensure that we will be successful in this endeavor.

We expect to rely on contract manufacturing relationships for lentiviral vectors and for the MB-108 oncolytic virus, as well as for any non-CAR T products that
we  may  in-license  or  acquire  in  the  future  for  co-administration  with  our  CAR  T  products.  However,  there  can  be  no  assurance  that  we  will  be  able  to
successfully contract with such manufacturers on terms acceptable to us, or at all.

Contract manufacturers for these current and potential future non-CAR T products would be subject to ongoing periodic and unannounced inspections by the
FDA, the U.S. Drug Enforcement Administration (“DEA”) and corresponding state agencies to ensure strict compliance with the Current Good Manufacturing
Practice regulations (“cGMP”) and other state and federal regulations. Our contractors, if any, in Europe would face similar challenges from the numerous EU
and  member  state  regulatory  agencies  and  authorized  bodies.  We  do  not  have  control  over  third-party  manufacturers’  compliance  with  these  regulations  and
standards,  other  than  through  contractual  obligations.  If  they  are  deemed  out  of  compliance  with  cGMPs,  product  recalls  could  result,  inventory  could  be
destroyed, production could be stopped, and supplies could be delayed or otherwise disrupted.

If  we  need  to  change  manufacturers  for  these  current  and  potential  future  non-CAR  T  products  after  commercialization,  the  FDA  and  corresponding  foreign
regulatory agencies must approve these new manufacturers in advance, which will involve testing and additional inspections to ensure compliance with FDA
regulations  and  standards  and  may  require  significant  lead  times  and  delay.  Furthermore,  switching  manufacturers  may  be  difficult  because  the  number  of
potential manufacturers is limited. It may be difficult or impossible for us to find a replacement manufacturer quickly or on terms acceptable to us, or at all.

GOVERNMENT AND INDUSTRY REGULATIONS

Numerous  governmental  authorities,  principally  the  FDA  and  corresponding  state  and  foreign  regulatory  agencies,  impose  substantial  regulations  upon  the
clinical development, manufacture and marketing of our product candidates, as well as our ongoing research and development activities. None of our product
candidates has been approved for sale in any market in which we have marketing rights. Before marketing in the U.S., any drug that we develop must undergo
rigorous pre-clinical testing and clinical trials and an extensive regulatory approval process implemented by the FDA under the Food, Drug and Cosmetic Act
(“FDCA”). The FDA regulates, among other things, the pre-clinical and clinical testing, safety, efficacy, approval, manufacturing, record keeping, adverse event
reporting, packaging, labeling, storage, advertising, promotion, export, and the sale and distribution of biopharmaceutical products.

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The regulatory review and approval process is lengthy, expensive and uncertain. We are required to submit extensive preclinical and clinical data and supporting
information to the FDA for each indication or use to establish a product candidate’s safety and efficacy before we can secure FDA approval to market or sell a
product in the U.S. The approval process takes many years, requires the expenditure of substantial resources and may involve ongoing requirements for post-
marketing studies or surveillance. Before commencing clinical trials in humans, we must submit an IND to the FDA containing, among other things, preclinical
data, chemistry, manufacturing and control information, and an investigative plan. Our submission of an IND may not result in FDA authorization to commence
a clinical trial.

The FDA may permit expedited development, evaluation, and marketing of new therapies intended to treat persons with serious or life-threatening conditions for
which there is an unmet medical need under its fast track drug development programs. A sponsor can apply for fast track designation at the time of submission
of an IND, or at any time prior to receiving marketing approval of the new drug application (“NDA”) or biologics license application (“BLA”). To receive fast
track designation, an applicant must demonstrate:

●

●

●

that the therapy is intended to treat a serious or life-threatening condition;

that the therapy is intended to treat a serious aspect of the condition; and

that the therapy has the potential to address unmet medical needs, and this potential is being evaluated in the planned drug development program.

The FDA must respond to a request for fast track designation within 60 calendar days of receipt of the request. Over the course of development, a product in a
fast track development program must continue to meet the criteria for fast track designation. Sponsors of products in fast track drug development programs must
be  in  regular  contact  with  the  reviewing  division  of  the  FDA  to  ensure  that  the  evidence  necessary  to  support  marketing  approval  will  be  developed  and
presented in a format conducive to an efficient review. Sponsors of products in fast track drug development programs ordinarily are eligible for priority review
of a completed application in six months or less and also may be permitted to submit portions of an NDA or BLA to the FDA for review before the complete
application is submitted.

In accordance with the FDCA, sponsors of drugs for serious or life-threatening diseases that fill an unmet medical need may seek approval under the FDA’s
accelerated  approval  regulations.  Under  this  authority,  the  FDA  may  grant  marketing  approval  for  a  new  drug  product  on  the  basis  of  adequate  and  well-
controlled clinical trials establishing that the drug product has an effect on a surrogate endpoint that is reasonably likely, based on epidemiologic, therapeutic,
pathophysiologic, or other evidence, to predict clinical benefit or on the basis of an effect on a clinical endpoint other than survival or irreversible morbidity.
Approval will be subject to the requirement that the applicant study the drug further to verify and describe its clinical benefit where there is uncertainty as to the
relation of the surrogate endpoint to clinical benefit or uncertainty as to the relation of the observed clinical benefit to ultimate outcome. Post-marketing studies
are  usually  underway  at  the  time  an  applicant  files  the  NDA.  When  required  to  be  conducted,  such  post-marketing  studies  must  also  be  adequate  and  well-
controlled. The applicant must carry out any such post-marketing studies with due diligence. Many companies who have been granted the right to utilize an
accelerated approval approach have failed to obtain approval. Moreover, negative or inconclusive results from the clinical trials we hope to conduct or adverse
medical  events  could  cause  us  to  have  to  repeat  or  terminate  the  clinical  trials. Accordingly,  we  may  not  be  able  to  complete  the  clinical  trials  within  an
acceptable time frame, if at all, and, therefore, could not submit the NDA or BLA to the FDA or foreign regulatory authorities for marketing approval.

Clinical testing must meet requirements for institutional review board oversight, informed consent and good clinical practices, and must be conducted pursuant
to an IND, unless exempted.

For purposes of NDA or BLA approval, clinical trials are typically conducted in the following sequential phases:

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●

Phase 1: The drug is administered to a small group of humans, either healthy volunteers or patients, for the first time to test for safety, dosage tolerance,
absorption, metabolism, excretion and clinical pharmacology.

Phase 2:  Studies  are  conducted  on  a  larger  number  of  patients  to  assess  the  efficacy  of  the  product,  to  ascertain  dose  tolerance  and  the  optimal  dose
range, and to gather additional data relating to safety and potential adverse events.

Phase 3: Studies establish safety and efficacy in an expanded patient population.

Phase 4: Phase 4 post-marketing studies may be requested by the FDA to find out more about the drug’s long-term risks, benefits, and optimal use, or to
test the drug in different patient populations.

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The length of time necessary to complete clinical trials varies significantly and may be difficult to predict. Clinical results are frequently susceptible to varying
interpretations that may delay, limit or prevent regulatory approvals. Additional factors that can cause delay or termination of our clinical trials, or that may
increase the costs of these trials, include:

●

●

●

●

●

●

slow patient enrollment due to the nature of the clinical trial plan, the proximity of patients to clinical sites, the eligibility criteria for participation in the
study or other factors;

inadequately trained or insufficient personnel at the study site to assist in overseeing and monitoring clinical trials or delays in approvals from a study
site’s review board;

longer treatment time required to demonstrate efficacy or determine the appropriate product dose;

insufficient supply of the product candidates;

adverse medical events or side effects in treated patients; and

ineffectiveness of the product candidates.

In addition, the FDA, equivalent foreign regulatory authority, or a data safety monitoring committee for a trial may place a clinical trial on hold or terminate it if
it concludes that subjects are being exposed to an unacceptable health risk, or for futility. Any drug is likely to produce some toxicity or undesirable side effects
in animals and in humans when administered at sufficiently high doses and/or for a sufficiently long period of time. Unacceptable toxicity or side effects may
occur at any dose level at any time in the course of studies in animals designed to identify unacceptable effects of a product candidate, known as toxicological
studies, or clinical trials of product candidates. The appearance of any unacceptable toxicity or side effect could cause us or regulatory authorities to interrupt,
limit, delay or abort the development of any of our product candidates and could ultimately prevent approval by the FDA or foreign regulatory authorities for
any or all targeted indications.

Sponsors of drugs may apply for a special protocol assessment (“SPA”) from the FDA for studies intended to form the primary basis of an efficacy claim. The
SPA process is a procedure by which the FDA provides official evaluation and written guidance on the design and size of proposed protocols that are intended to
form the basis for an NDA or BLA. However, final marketing approval depends on the results of efficacy, the adverse event profile and an evaluation of the
benefit/risk of treatment demonstrated in the pivotal 3 trial. The SPA may only be changed through a written agreement between the sponsor and the FDA, or in
rare cases if the FDA becomes aware of a substantial scientific issue essential to product safety or efficacy the SPA can be rescinded.

Before receiving FDA approval to market a product, we must demonstrate that the product is safe and effective for its intended use by submitting to the FDA an
NDA or BLA containing the preclinical and clinical data that have been accumulated, together with chemistry and manufacturing and controls specifications and
information, and proposed labeling, among other things. The FDA may refuse to accept an NDA or BLA for filing if certain content criteria are not met and,
even after accepting an NDA or BLA, the FDA may require additional information, including clinical data, before approval for marketing a product.

Although uncommon, the FDA may request a Risk Evaluation and Mitigation Strategy, or REMS, as part of an NDA or BLA approval for products with serious
safety concerns to help ensure that the benefits of the product outweigh the risks. The REMS plan contains post-market obligations of the sponsor to train
prescribing physicians, monitor off-label drug use, and perhaps the conduct of Phase 4 follow-up studies and registries to ensure the continued safe use of the
drug.

As part of the approval process, the FDA must inspect and approve each manufacturing facility. Among the conditions of approval is the requirement that a
manufacturer’s  quality  control  and  manufacturing  procedures  conform  to  cGMP.  Manufacturers  must  expend  significant  time,  money  and  effort  to  ensure
continued compliance, and the FDA conducts periodic inspections to certify compliance. It may be difficult for our manufacturers or for us to comply with the
applicable cGMP, as interpreted by the FDA, and other FDA regulatory requirements. If we, or our contract manufacturers, fail to comply, then the FDA may
not allow us to market products that have been affected by the failure.

If the FDA grants approval, the approval will be limited to those conditions and patient populations for which the product is safe and effective, as demonstrated
through  clinical  studies  and  as  reflected  in  the  approved  labeling.  Further,  a  product  may  be  marketed  only  in  those  dosage  forms  and  for  those  indications
approved in the NDA or BLA. Certain changes to an approved NDA or BLA, including, with certain exceptions, any significant changes to labeling, may require
prior approval of a supplemental application before the drug may be marketed as changed. Any products that we manufacture or distribute pursuant to FDA
approvals are subject to continuing monitoring and

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regulation by the FDA, including compliance with cGMP and the reporting of adverse experiences with the drugs. The nature of marketing claims that the FDA
will permit us to make in the labeling and advertising of our products will generally be limited to those specified in FDA approved labeling, and the advertising
of our products will be subject to comprehensive monitoring and regulation by the FDA. Drugs whose review was accelerated may carry additional restrictions
on marketing activities, including the requirement that all promotional materials are pre-submitted to the FDA. Claims exceeding those contained in approved
labeling  will  constitute  a  violation  of  the  FDCA.  Violations  of  the  FDCA  or  regulatory  requirements  at  any  time  during  the  product  development  process,
approval  process,  or  marketing  and  sale  following  approval  may  result  in  agency  enforcement  actions,  including  withdrawal  of  approval,  recall,  seizure  of
products,  warning  letters,  injunctions,  fines  and/or  civil  or  criminal  penalties. Any  agency  enforcement  action  could  have  a  material  adverse  effect  on  our
business.

Failure  to  comply  with  applicable  federal,  state  and  foreign  laws  and  regulations  would  likely  have  a  material  adverse  effect  on  our  business.  In  addition,
federal, state and foreign laws and regulations regarding the manufacture and sale of new drugs are subject to future changes.

Other Healthcare Laws and Compliance Requirements

In the U.S., our activities are potentially subject to regulation by various federal, state and local authorities in addition to the FDA, including the Centers for
Medicare and Medicaid Services (formerly the Health Care Financing Administration), other divisions of the United States Department of Health and Human
Services (e.g., the Office of Inspector General), the United States Department of Justice and individual United States Attorney offices within the Department of
Justice, and state and local governments.

Pharmaceutical Coverage, Pricing and Reimbursement

In  the  U.S.  and  markets  in  other  countries,  sales  of  any  products  for  which  we  receive  regulatory  approval  for  commercial  sale  will  depend  in  part  on  the
availability of reimbursement from third-party payors, including government health administrative authorities, managed care providers, private health insurers
and  other  organizations.  Third-party  payors  are  increasingly  examining  the  medical  necessity  and  cost-effectiveness  of  medical  products  and  services,  in
addition to their safety and efficacy, and, accordingly, significant uncertainty exists as to the reimbursement status of newly approved therapeutics. Adequate
third-party  reimbursement  may  not  be  available  for  our  products  to  enable  us  to  realize  an  appropriate  return  on  our  investment  in  research  and  product
development. We are unable to predict the future course of federal or state health care legislation and regulations, including regulations that will be issued to
implement provisions of the health care reform legislation enacted in 2010, known as the Affordable Care Act. The Affordable Care Act and further changes in
the law or regulatory framework could have a material adverse effect on our business.

International Regulation

In addition to regulations in the U.S., there are a variety of foreign regulations governing clinical trials and commercial sales and distribution of any product
candidates. The approval process varies from country to country, and the time may be longer or shorter than that required for FDA approval.

Item 1A.

Risk Factors

Investing  in  our  Common  Stock  or  any  other  type  of  equity  or  debt  securities  we  may  offer  (together,  our  “Securities”)  involves  a  high  degree  of  risk.  The
following information sets forth risk factors that could cause our actual results to differ materially from those contained in forward-looking statements we have
made in this Form 10-K and those we may make from time to time. You should carefully consider the risks described below, in addition to the other information
contained in this Form 10-K, before making an investment decision. Our business, financial condition or results of operations could be harmed by any of these
risks. The risks and uncertainties described below are not the only ones we face. Additional risks not presently known to us or other factors not perceived by us
to present significant risks to our business at this time also may impair our business operations.

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Risks Related to Our Finances and Capital Requirements

We have incurred significant losses since our inception. We expect to incur losses for the foreseeable future and may never achieve or maintain profitability.
We  do  not  have  any  products  that  are  approved  for  commercial  sale  and  therefore  do  not  expect  to  generate  any  revenues  from  product  sales  in  the
foreseeable future, if ever.

We are an emerging growth company with a limited operating history. We have focused primarily on in-licensing and developing our product candidates, with
the goal of supporting regulatory approval for these product candidates. We have incurred losses since our inception in March 2015 and have an accumulated
deficit  of  $185.5  million  as  of  December  31,  2020.  We  expect  to  continue  to  incur  significant  operating  losses  for  the  foreseeable  future.  We  also  do  not
anticipate that we will achieve profitability for a period of time after generating material revenues, if ever. If we are unable to generate revenues, we will not
become profitable and may be unable to continue operations without continued funding.

Because of the numerous risks and uncertainties associated with developing pharmaceutical products, we are unable to predict the timing or amount of increased
expenses or when or if, we will be able to achieve profitability. Our net losses may fluctuate significantly from quarter to quarter and year to year. We anticipate
that our expenses will increase substantially if:

●

one  or  more  of  our  product  candidates  receive  regulatory  approval  and  are  approved  for  commercial  sale,  due  to  our  need  to  establish  the  necessary
commercial infrastructure to launch and commercialize this product candidate without substantial delays, including hiring sales and marketing personnel
and contracting with third parties for manufacturing, testing, warehousing, distribution, cash collection and related commercial activities;

● we are required by the FDA or foreign regulatory authorities to perform studies in addition to those currently expected;

●

there are any delays in completing our clinical trials or the development of any of our product candidates;

● we execute other collaborative, licensing or similar arrangements that require us to make payments to collaborators or licensors;

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●

●

there are variations in the level of expenses related to our future development programs;

there are any product liability or intellectual property infringement lawsuits in which we may become involved; and

there are any regulatory developments affecting product candidates of our competitors.

Our  ability  to  become  profitable  depends  upon  our  ability  to  generate  revenue.  To  date,  we  have  not  generated  any  revenue  from  our  development  stage
products, and we do not know when, or if, we will generate any revenue. Our ability to generate revenue depends on a number of factors, including, but not
limited to, our ability to:

●

obtain regulatory approval for one or more of our product candidates, or any future product candidate that we may license or acquire;

● manufacture  or  have  manufactured  commercial  quantities  of  one  or  more  of  our  product  candidates  or  any  future  product  candidate,  if  approved,  at

acceptable cost levels; and

●

develop a commercial organization and the supporting infrastructure required to successfully market and sell one or more of our product candidates or
any future product candidate, if approved.

Even if we do achieve profitability, we may not be able to sustain or increase profitability on a quarterly or annual basis. Our failure to become and remain
profitable would depress the value of our company and could impair our ability to raise capital, expand our business, maintain our research and development
efforts, diversify our product offerings or even continue our operations. A decline in the value of our company could also cause you to lose all or part of your
investment.

Our short operating history makes it difficult to evaluate our business and prospects.

We have only been conducting operations since our incorporation in March 2015. Our operations to date have been limited to preclinical operations and the in-
licensing of our product candidates. We have not yet demonstrated an ability to successfully complete clinical trials, obtain regulatory approvals, manufacture a
clinical scale or commercial scale product, or arrange for a third party to do so on our behalf, or conduct sales and marketing activities necessary for successful
product commercialization. Consequently, any predictions about our future

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performance may not be as accurate as they could be if we had a history of successfully developing and commercializing pharmaceutical products.

In addition, as a young business, we may encounter unforeseen expenses, difficulties, complications, delays and other known and unknown factors. We will need
to expand our capabilities to support commercial activities. We may not be successful in adding such capabilities.

We expect our financial condition and operating results to continue to fluctuate significantly from quarter to quarter and year to year due to a variety of factors,
many  of  which  are  beyond  our  control. Accordingly,  you  should  not  rely  upon  the  results  of  any  past  quarterly  period  as  an  indication  of  future  operating
performance.

We will require substantial additional funding which may not be available to us on acceptable terms, or at all. If we fail to raise the necessary additional
capital, we may be unable to complete the development and commercialization of our product candidates, or continue our development programs.

Our  operations  have  consumed  substantial  amounts  of  cash  since  inception.  We  expect  to  significantly  increase  our  spending  to  advance  the  preclinical  and
clinical development of our product candidates and launch and commercialize any product candidates for which we may receive regulatory approval, including
building  our  own  commercial  organizations  to  address  certain  markets.  We  will  require  additional  capital  for  the  further  development  and,  if  approved,
commercialization of our product candidates, as well as to fund our other operating expenses and capital expenditures. As of December 31, 2020, we had $98.8
million in cash and restricted cash. We cannot provide any assurance that we will be able to raise funds to complete the development of our product candidates.
Additionally, we may have to delay or terminate the development of certain product candidates if we are unable to secure additional funding; any such delay or
termination, or the announcement of any such delay or termination, may impact our potential growth and have a material adverse effect on the value of our debt
and equity securities.

We cannot be certain that additional funding will be available on acceptable terms, or at all. If we are unable to raise additional capital in sufficient amounts or
on terms acceptable to us, we may have to significantly delay, scale back or discontinue the development or, if approved, commercialization of one or more of
our product candidates. We may also seek collaborators for one or more of our current or future product candidates at an earlier stage than otherwise would be
desirable or on terms that are less favorable than might otherwise be available. Any of these events could significantly harm our business, financial condition
and prospects.

Our future funding requirements will depend on many factors, including, but not limited to:

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●

●

●

●

the timing, design and conduct of, and results from, preclinical studies and clinical trials for our product candidates;

the potential for delays in our efforts to seek regulatory approval for our product candidates, and any costs associated with such delays;

the costs of establishing a commercial organization to sell, market and distribute our product candidates;

the rate of progress and costs of our efforts to prepare for the submission of an NDA or BLA for any product candidates that we may in-license or acquire
in the future, and the potential that we may need to conduct additional clinical trials to support applications for regulatory approval;

the costs of filing, prosecuting, defending and enforcing any patent claims and other intellectual property rights associated with our product candidates,
including any such costs we may be required to expend if our licensors are unwilling or unable to do so;

the cost and timing of securing sufficient supplies of our product candidates from  our  contract  manufacturers  for  clinical  trials  and  in  preparation  for
commercialization;

the effect of competing technological and market developments;

the terms and timing of any collaborative, licensing, co-promotion or other arrangements that we may establish;

if one or more of our product candidates are approved, the potential that we may be required to file a lawsuit to defend our patent rights or regulatory
exclusivities from challenges by companies seeking to market generic versions of one or more of our product candidates; and

●

the success of the commercialization of one or more of our product candidates, if approved.

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Future capital requirements will also depend on the extent to which we acquire or invest in additional complementary businesses, products and technologies,
although we currently have no commitments or agreements relating to any of these types of transactions.

In order to carry out our business plan and implement our strategy, we anticipate that we will need to obtain additional financing from time to time and may
choose to raise additional funds through strategic collaborations, licensing arrangements, public or private equity or debt financing, bank lines of credit, asset
sales, government grants, or other arrangements. We cannot be sure that any additional funding, if needed, will be available on terms favorable to us or at all.
Furthermore, any additional equity or equity-related financing may be dilutive to our stockholders, and debt or equity financing, if available, may subject us to
restrictive  covenants  and  significant  interest  costs.  If  we  obtain  funding  through  a  strategic  collaboration  or  licensing  arrangement,  we  may  be  required  to
relinquish our rights to certain of our product candidates or marketing territories.

Our inability to raise capital when needed would harm our business, financial condition and results of operations, and could cause our stock value to decline or
require that we wind down our operations altogether.

Raising additional capital may cause dilution to our existing stockholders, restrict our operations or require us to relinquish proprietary rights.

Until such time, if ever, as we can generate substantial product revenue, we expect to finance our cash needs through a combination of equity offerings, debt
financings, grants and license and development agreements in connection with any collaborations. To the extent that we raise additional capital through the sale
of equity or convertible debt securities, your ownership interest will be diluted, and the terms of these securities may include liquidation or other preferences
that adversely affect your rights as a stockholder. Debt financing and preferred equity financing, if available, may involve agreements that include covenants
limiting or restricting our ability to take specific actions, such as incurring additional debt, making capital expenditures or declaring dividends.

If we raise additional funds through collaborations, strategic alliances or marketing, distribution or licensing arrangements with third parties, we may have to
relinquish  valuable  rights  to  our  technologies,  future  revenue  streams,  research  programs  or  product  candidates  or  grant  licenses  on  terms  that  may  not  be
favorable to us. If we are unable to raise additional funds through equity or debt financings when needed, we may be required to delay, limit, reduce or terminate
our product development or future commercialization efforts or grant rights to develop and market product candidates that we would otherwise prefer to develop
and market ourselves.

We  will  continue  to  incur  significant  increased  costs  as  a  result  of  operating  as  a  public  company,  and  our  management  will  be  required  to  devote
substantial time to new compliance initiatives.

As a public company, we incur significant legal, accounting and other expenses under the Sarbanes-Oxley Act of 2002, or the Sarbanes-Oxley Act, as well as
rules  subsequently  implemented  by  the  SEC,  and  the  rules  of  the  Nasdaq  Stock  Exchange.  These  rules  impose  various  requirements  on  public  companies,
including  requiring  establishment  and  maintenance  of  effective  disclosure  and  financial  controls  and  appropriate  corporate  governance  practices.  Our
management  and  other  personnel  have  devoted  and  will  continue  to  devote  a  substantial  amount  of  time  to  these  compliance  initiatives.  Moreover,  these
rules and regulations increase our legal and financial compliance costs and make some activities more time-consuming and costly. For example, these rules and
regulations make it more difficult and more expensive for us to obtain director and officer liability insurance, and we may be required to accept reduced policy
limits and coverage or incur substantially higher costs to obtain the same or similar coverage. As a result, it may be more difficult for us to attract and retain
qualified persons to serve on our board of directors, our board committees or as executive officers.

The Sarbanes-Oxley Act requires, among other things, that we maintain effective internal controls for financial reporting and disclosure controls and procedures.
As  a  result,  we  are  required  to  periodically  perform  an  evaluation  of  our  internal  controls  over  financial  reporting  to  allow  management  to  report  on  the
effectiveness of those controls, as required by Section 404 of the Sarbanes-Oxley Act. Additionally, our independent auditors are required to perform a similar
evaluation and report on the effectiveness of our internal controls over financial reporting. These efforts to comply with Section 404 and related regulations have
required, and continue to require, the commitment of significant financial and managerial resources. While we anticipate maintaining the integrity of our internal
controls  over  financial  reporting  and  all  other  aspects  of  Section  404,  we  cannot  be  certain  that  a  material  weakness  will  not  be  identified  when  we  test  the
effectiveness of our control systems in the future. If a material weakness is identified, we could be subject to sanctions or investigations by the SEC or other
regulatory  authorities,  which  would  require  additional  financial  and  management  resources,  costly  litigation  or  a  loss  of  public  confidence  in  our  internal
controls, which could have an adverse effect on the market price of our stock.

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Compliance  with  the  Sarbanes-Oxley  Act  of  2002  will  require  substantial  financial  and  management  resources  and  may  increase  the  time  and  costs  of
completing an acquisition.

A business that we identify as a potential acquisition target may not be in compliance with the provisions of the Sarbanes-Oxley Act regarding the adequacy of
internal controls. The development of the internal controls of any such entity to achieve compliance with the Sarbanes-Oxley Act may increase the time and costs
necessary  to  complete  any  such  acquisition.  Furthermore,  any  failure  to  implement  required  new  or  improved  controls,  or  difficulties  encountered  in  the
implementation of adequate controls over our financial processes and reporting in the future, could harm our operating results or cause us to fail to meet our
reporting obligations. Inferior internal controls could also cause investors to lose confidence in our reported financial information, which could have a negative
effect on the trading price of our securities.

Our ability to use our pre-change NOLs and other pre-change tax attributes to offset post-change taxable income or taxes may be subject to limitation.

We may, from time to time, carry net operating loss carryforwards (“NOLs”) as deferred tax assets on our balance sheet. Under Sections 382 and 383 of the
Internal  Revenue  Code  of  1986,  as  amended,  if  a  corporation  undergoes  an  “ownership  change”  (generally  defined  as  a  greater  than  50-percentage-  point
cumulative change (by value) in the equity ownership of certain stockholders over a rolling three-year period), the corporation’s ability to use its pre-change
NOLs and other pre-change tax attributes to offset its post-change taxable income or taxes may be limited. We may experience ownership changes in the future
as a result of shifts in our stock ownership, some of which changes are outside our control. As a result, our ability to use our pre-change NOLs and other pre-
change tax attributes to offset post-change taxable income or taxes may be subject to limitation.

Raising funds through lending arrangements may restrict our operations or produce other adverse results.

Our current Loan Agreement with Horizon, which we entered into in March 2019, contains a variety of affirmative and negative covenants, including required
financial  reporting,  limitations  on  certain  dispositions  of  assets,  limitations  on  the  incurrence  of  additional  debt  and  other  requirements.  To  secure  our
performance of our obligations under this Loan Agreement, we granted a security interest in substantially all of our assets, other than certain intellectual property
assets, to Horizon. Our failure to comply with the covenants in the Loan Agreement, the occurrence of a material impairment in our prospect of repayment or in
the perfection or priority of Horizon’s lien on our assets, as determined by Horizon, or the occurrence of certain other specified events could result in an event of
default  that,  if  not  cured  or  waived,  could  result  in  the  acceleration  of  all  or  a  substantial  portion  of  our  debt,  potential  foreclosure  on  our  assets  and  other
adverse results. Additionally, we are bound by certain negative covenants setting forth actions that are not permitted to be taken during the term of the Loan
Agreement without consent of Horizon, including, without limitation, incurring certain additional indebtedness, making certain asset dispositions, entering into
certain mergers, acquisitions or other business combination transactions or incurring any non-permitted lien or other encumbrance on our assets. The foregoing
prohibitions and constraints on our operations could result in our inability to: (i) acquire promising intellectual property or other assets on desired timelines or
terms;  (ii)  reduce  costs  by  disposing  of  assets  or  business  segments  no  longer  deemed  advantageous  to  retain;  (iii)  stimulate  further  corporate  growth  or
development through the assumption of additional debt; or (iv) enter into other arrangements that necessitate the imposition of a lien on corporate assets.

Risks Related to Our Business Strategy, Structure, and Organization

We currently have no products for sale. We are heavily dependent on the success of our product candidates, and we cannot give any assurances that any of
our product candidates will receive regulatory approval or be successfully commercialized.

To date, we have invested a significant portion of our efforts and financial resources in the acquisition and development of our product candidates. We have not
demonstrated our ability to perform the functions necessary for the successful acquisition, development or commercialization of the technologies we are seeking
to develop. As an early stage company, we have limited experience and have not yet demonstrated an ability to successfully overcome many of the risks and
uncertainties  frequently  encountered  by  companies  in  new  and  rapidly  evolving  fields,  particularly  in  the  biopharmaceutical  area.  Our  future  success  is
substantially  dependent  on  our  ability  to  successfully  develop,  obtain  regulatory  approval  for,  and  then  commercialize  such  product  candidates.  Most  of  our
product candidates are currently in early stage clinical trials. Our business depends entirely on the successful development and commercialization of our product
candidates, which may never occur. We currently have no drug products for sale, currently generate no revenues from sales of any drug products, and may never
be able to develop or commercialize a marketable product.

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The  successful  development,  and  any  commercialization,  of  our  technologies  and  any  product  candidates  that  may  occur  would  require  us  to  successfully
perform a variety of functions, including:

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developing our technology platform;

identifying, developing, formulating, manufacturing and commercializing product candidates;

entering into successful licensing and other arrangements with product development partners;

participating in regulatory approval processes, including ultimately gaining approval to market a drug product, which may not occur;

obtaining  sufficient  quantities  of  our  product  candidates  from  our  third-party  manufacturers  to  meet  clinical  trial  needs  and,  if  approved,  to  meet
commercial demand at launch and thereafter;

establishing and maintaining agreements with wholesalers, distributors and group purchasing organizations on commercially reasonable terms;

conducting sales and marketing activities including hiring, training, deploying and supporting our sales force and creating market demand for our product
candidates through our own marketing and sales activities, and any other arrangements to promote our product candidates that we may establish; and

● maintaining patent protection and regulatory exclusivity for our product candidates.

Our  operations  have  been  limited  to  organizing  our  company,  acquiring,  developing  and  securing  our  proprietary  technology  and  identifying  and  obtaining
preclinical data or clinical data for various product candidates. These operations provide a limited basis for you to assess our ability to continue to develop our
technology,  identify  product  candidates,  develop  and  commercialize  any  product  candidates  we  are  able  to  identify  and  enter  into  successful  collaborative
arrangements with other companies, as well as for you to assess the advisability of investing in our securities. Each of these requirements will require substantial
time, effort and financial resources.

Each  of  our  product  candidates  will  require  additional  clinical  development,  management  of  clinical  and  manufacturing  activities,  regulatory  approval  in  the
jurisdictions  in  which  we  plan  to  market  the  product,  obtaining  manufacturing  supply,  building  a  commercial  organization,  and  significant  marketing  efforts
before we generate any revenues from product sales, which may not occur. We are not permitted to market or promote any of our product candidates in the U.S.
or  any  other  jurisdiction  before  we  receive  regulatory  approval  from  the  FDA  or  comparable  foreign  regulatory  authority,  respectively,  and  we  may  never
receive such regulatory approval for any of our product candidates.

Our future growth depends in part on our ability to identify and acquire or in-license products, and if we do not successfully identify and acquire or in-
license related product candidates or integrate them into our operations, we may have limited growth opportunities.

An  important  part  of  our  business  strategy  is  to  continue  to  develop  a  pipeline  of  product  candidates  by  acquiring  or  in-licensing  products,  businesses  or
technologies that we believe are a strategic fit with our focus on ex vivo lentiviral gene therapy for rare genetic diseases and on novel combinations of CAR T
cells with immuno-oncology antibodies, other biologics, and small molecule kinase inhibitors. Future in-licenses or acquisitions, however, may entail numerous
operational and financial risks, including, but not necessarily limited to:

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exposure to unknown liabilities;

disruption of our business and diversion of our management’s time and attention to develop acquired products or technologies;

difficulty  or  inability  to  secure  financing  to  fund  development  activities  for  such  acquired  or  in-licensed  technologies  in  the  current  economic
environment;

incurrence of substantial debt or dilutive issuances of securities to pay for acquisitions;

higher than expected acquisition and integration costs;

increased amortization expenses;

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difficulty and cost in combining the operations and personnel of any acquired businesses with our operations and personnel;

impairment of relationships with key suppliers or customers of any acquired businesses due to changes in management and ownership; and

inability to retain key employees of any acquired businesses.

We have limited resources to identify and execute the acquisition or in-licensing of third-party products, businesses and technologies and integrate them into our
current infrastructure. In particular, we may compete with larger pharmaceutical companies and other competitors in our efforts to establish new collaborations
and  in-licensing  opportunities.  These  competitors  may  have  access  to  greater  financial  resources  than  us  and  may  have  greater  expertise  in  identifying  and
evaluating new opportunities. Moreover, we may devote resources to potential acquisitions or in-licensing opportunities that are never completed, or we may fail
to realize the anticipated benefits of such efforts.

Our approach to the development of our product candidates is unproven, and we do not know whether we will be able to develop any products of commercial
value.

Our products candidates are emerging technologies and, consequently, it is conceivable that such technologies may ultimately fail to develop into commercially
viable therapies to treat human patients with cancer or other diseases. One of the reasons for the lack of commercial viability could be our inability to obtain
regulatory approval for such technologies.

CAR T is a new approach to cancer treatment that presents significant challenges.

We  have  concentrated  much  of  our  research  and  development  efforts  on  CAR  T  technology,  and  our  future  success  is  highly  dependent  on  the  successful
development of T cell immunotherapies in general and our CAR T technology and product candidates in particular. Because CAR T is a new approach to cancer
immunotherapy and cancer treatment generally, developing and commercializing our product candidates subjects us to a number of challenges, including, but
not necessarily limited to:

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obtaining regulatory approval from the FDA and other regulatory authorities that may have very limited experience with the commercial development of
genetically modified T cell therapies for cancer;

developing and deploying consistent and reliable processes for engineering a patient’s T cells ex vivo and infusing the engineered T cells back into the
patient;

conditioning patients with chemotherapy in conjunction with delivering each of our products, which may increase the risk of adverse side effects of our
products;

educating medical personnel regarding the potential side effect profile of each of our products;

developing processes for the safe administration of these products, including long-term follow-up for all patients who receive our product candidates;

sourcing clinical and, if approved, commercial supplies for the materials used to manufacture and process our product candidates;

developing a manufacturing process and distribution network with a cost of goods that allows for an attractive return on investment;

establishing  sales  and  marketing  capabilities  after  obtaining  any  regulatory  approval  to  gain  market  acceptance,  and  obtaining  adequate  coverage,
reimbursement and pricing by third-party payors and government authorities; and

●

developing therapies for types of cancers beyond those addressed by our current product candidates.

We may expend our limited resources to pursue a particular product candidate or indication and fail to capitalize on product candidates or indications that
may be more profitable or for which there is a greater likelihood of success.

Because we have limited financial and managerial resources, we focus on research programs and product candidates that we identify for specific indications. As
a  result,  we  may  forego  or  delay  pursuit  of  opportunities  with  other  product  candidates  or  for  other  indications  that  later  prove  to  have  greater  commercial
potential. Our resource allocation decisions may cause us to fail to capitalize on viable commercial products or profitable market opportunities. Our spending on
current and future research and development programs and product candidates

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for specific indications may not yield any commercially viable products. If we do not accurately and/or effectively evaluate the commercial potential or target
market  for  a  particular  product  candidate,  we  may  relinquish  valuable  rights  to  that  product  candidate  through  collaboration,  licensing  or  other  royalty
arrangements in cases in which it would have been more advantageous for us to retain sole development and commercialization rights to such product candidate.

We  are  an  “emerging  growth  company”  and  a  "smaller  reporting  company,"  and  the  reduced  disclosure  requirements  applicable  to  emerging  growth
companies and smaller reporting companies may make our common stock less attractive to investors.

We are an “emerging growth company” as that term is used in the JOBS Act, and may remain an emerging growth company until the earlier of (1) the last day
of the fiscal year (a) following the fifth anniversary, in 2022, of the completion of the initial public offering of our common stock, (b) in which we have total
annual gross revenue of at least $1.07 billion, or (c) in which we are deemed to be a large accelerated filer, which means the market value of our outstanding
common stock that are held by non-affiliates exceeds $700 million as of the prior June 30, and (2) the date on which we have issued more than $1.0 billion in
non-convertible  debt  during  the  prior  three  year  period.  For  so  long  as  we  remain  an  emerging  growth  company,  we  are  permitted  and  intend  to  rely  on
exemptions  from  certain  disclosure  requirements  that  are  applicable  to  other  public  companies  that  are  not  emerging  growth  companies.  These  exemptions
include:

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being  permitted  to  provide  only  two  years  of  audited  financial  statements,  in  addition  to  any  required  unaudited  interim  financial  statements,  with
correspondingly reduced “Management’s Discussion and Analysis of Financial Condition and Results of Operations” disclosure in this Annual Report on
Form 10-K;

not being required to comply with any requirement that may be adopted by the Public Company Accounting Oversight Board regarding mandatory audit
firm rotation or a supplement to the auditor’s report providing additional information about the audit and the financial statements;

disclosure obligations regarding executive compensation; and

exemptions from the requirements of holding a nonbinding advisory vote on executive compensation and shareholder approval of any golden parachute
payments not previously approved.

Further,  Section  102(b)(1)  of  the  JOBS Act  exempts  emerging  growth  companies  from  being  required  to  comply  with  new  or  revised  financial  accounting
standards until private companies (that is, those that have not had a Securities Act registration statement declared effective or do not have a class of securities
registered under the Exchange Act) are required to comply with the new or revised financial accounting standards. The JOBS Act provides that a company can
elect to opt out of the extended transition period and comply with the requirements that apply to non-emerging growth companies but any such an election to opt
out is irrevocable. We have elected to opt out of such extended transition period which means that when a standard is issued or revised, and it has different
application dates for public or private companies, we, as an emerging growth company, will adopt the new or revised standard. This may make comparison of
our financial statements with another public company which has opted into using the extended transition period difficult or impossible because of the potential
differences in accountant standards used.

We are also a smaller reporting company, and we will remain a smaller reporting company until the fiscal year following the determination that our voting and
non-voting  common  shares  held  by  non-affiliates  is  more  than  $250  million  measured  on  the  last  business  day  of  our  second  fiscal  quarter,  or  our  annual
revenues are more than $100 million during the most recently completed fiscal year and our voting and non-voting common shares held by non-affiliates is more
than $700 million measured on the last business day of our second fiscal quarter. Similar to emerging growth companies, smaller reporting companies are able to
provide  simplified  executive  compensation  disclosure,  are  exempt  from  the  auditor  attestation  requirements  of  Section  404,  and  have  certain  other  reduced
disclosure obligations, including, among other things, being required to provide only two years of audited financial statements and not being required to provide
selected financial data, supplemental financial information or risk factors.

We have elected to take advantage of certain of the reduced reporting obligations available to us. We cannot predict whether investors will find our common
stock less attractive if we rely on these exemptions. If some investors find our common stock less attractive as a result, there may be a less active trading market
for our common stock and our stock price may be reduced or more volatile.

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Risks Inherent in Drug Development and Commercialization

Delays in the commencement or conduct of our clinical trials could result in increased costs and delay our ability to pursue regulatory approval.

The commencement or conduct of clinical trials can be delayed for a variety of reasons, including, but not necessarily limited to, delays in:

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obtaining regulatory approval to commence a clinical trial;

identifying, recruiting and training suitable clinical investigators;

reaching and preserving agreements on acceptable terms with prospective clinical research organizations (“CROs”) and trial sites, the terms of which can
be subject to extensive negotiation, may be subject to modification from time to time and may vary significantly among different CROs and trial sites;

obtaining sufficient quantities of a product candidate for use in clinical trials;

obtaining Institutional Review Board (“IRB”) or ethics committee approval to conduct a clinical trial at a prospective site;

developing and validating companion diagnostics on a timely basis, if required;

adding new clinical sites once a trial has begun;

change in the principal investigator or other key staff overseeing the clinical trial at a given site;

identifying, recruiting and enrolling patients to participate in a clinical trial; or

retaining (or replacing) patients who have initiated a clinical trial but who may withdraw due to adverse events from the therapy, insufficient efficacy,
fatigue with the clinical trial process, personal issues, or other reasons.

Any delays in the commencement of our clinical trials will delay our ability to pursue regulatory approval for product candidates. In addition, many of the factors
that cause, or lead to, a delay in the commencement of clinical trials may also ultimately lead to the denial of regulatory approval of a product candidate.

Suspensions or delays in the completion of clinical testing could result in increased costs and delay or prevent our ability to complete development of that
product or generate product revenues.

Once a clinical trial has begun, patient recruitment and enrollment may be slower than we anticipate due to the nature of the clinical trial plan, the proximity of
patients  to  clinical  sites,  the  eligibility  criteria  for  participation  in  the  study  or  other  factors.  Clinical  trials  may  also  be  delayed  as  a  result  of  ambiguous  or
negative  interim  results  or  difficulties  in  obtaining  sufficient  quantities  of  product  manufactured  in  accordance  with  regulatory  requirements  and  on  a  timely
basis. Further, a clinical trial may be modified, suspended or terminated by us, an IRB, an ethics committee or a data safety monitoring committee overseeing
the  clinical  trial,  any  clinical  trial  site  with  respect  to  that  site,  or  the  FDA  or  other  regulatory  authorities,  due  to  a  number  of  factors,  including,  but  not
necessarily limited to:

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failure to conduct the clinical trial in accordance with regulatory requirements or our clinical protocols;

inspection of the clinical trial operations or clinical trial site by the FDA or other regulatory authorities resulting in the imposition of a clinical hold;

stopping rules contained in the protocol;

unforeseen safety issues or any determination that the clinical trial presents unacceptable health risks; and

lack of adequate funding to continue the clinical trial.

Changes in regulatory requirements and guidance also may occur, and we may need to amend clinical trial protocols to reflect these changes. Amendments may
require us to resubmit clinical trial protocols to IRBs for re-examination, which may in turn impact the costs and timing

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of, and the likelihood of successfully completing, a clinical trial. If we experience delays in the completion of, or if we must suspend or terminate, any clinical
trial of any product candidate, our ability to obtain regulatory approval for that product candidate will be delayed, and the commercial prospects, if any, for the
product candidate may suffer as a result. In addition, many of these factors may also ultimately lead to the denial of regulatory approval of a product candidate.

Product candidates that we advance into clinical trials may not receive regulatory approval.

Pharmaceutical development has inherent risks. We will be required to demonstrate through well-controlled clinical trials that product candidates are effective
with a favorable benefit-risk profile for use in their target indications before seeking regulatory approvals for their commercial sale. Success in early clinical
trials  does  not  mean  that  later  clinical  trials  will  be  successful,  as  product  candidates  in  later-stage  clinical  trials  may  fail  to  demonstrate  sufficient  safety  or
efficacy  despite  having  progressed  through  initial  clinical  testing. Also,  we  may  need  to  conduct  additional  clinical  trials  that  are  not  currently  anticipated.
Companies frequently suffer significant setbacks in advanced clinical trials, even after earlier clinical trials have shown promising results. As a result, product
candidates that we advance into clinical trials may not receive regulatory approval.

In  addition,  even  if  our  product  candidates  were  to  obtain  approval,  regulatory  authorities  may  approve  any  such  product  candidates  or  any  future  product
candidate for fewer or more limited indications than we request, may not approve the price we intend to charge for our products, may grant approval contingent
on the performance of costly post-marketing clinical trials, or may approve a product candidate with a label that does not include the labeling claims necessary
or  desirable  for  the  successful  commercialization  of  that  product  candidate.  The  regulatory  authority  may  also  require  the  label  to  contain  warnings,
contraindications, or precautions that limit the commercialization of the product. In addition, the DEA (or foreign equivalent) may classify one or more of our
product candidates in scheduling under the Controlled Substances Act (or its foreign equivalent) that could impede such product’s commercial viability. Any of
these scenarios could impact the commercial prospects for one or more of our current or future product candidates.

Any  product  candidates  we  advance  into  clinical  development  are  subject  to  extensive  regulation,  which  can  be  costly  and  time  consuming,  cause
unanticipated delays or prevent the receipt of the required approvals to commercialize product candidates.

The  research  and  clinical  development,  testing,  manufacturing,  labeling,  storage,  record-keeping,  advertising,  promotion,  import,  export,  marketing  and
distribution of any product candidate, including our product candidates, is subject to extensive regulation by the FDA in the United States and by comparable
health authorities in foreign markets. In the United States, we are not permitted to market a product candidate until such product candidate’s Biologics License
Application (“BLA”) or NDA is approved by the FDA. The process of obtaining approval is uncertain, expensive, often spanning many years, and can vary
substantially based upon the type, complexity and novelty of the products involved. In addition to significant and expensive clinical testing requirements, our
ability to obtain marketing approval for product candidates depends on obtaining the final results of required non-clinical testing, including characterization of
the  manufactured  components  of  our  product  candidates  and  validation  of  our  manufacturing  processes.  The  FDA  may  determine  that  our  product
manufacturing processes, testing procedures or equipment and facilities are inadequate to support approval. Approval policies or regulations may change, and
the FDA has substantial discretion in the pharmaceutical approval process, including the ability to delay, limit or deny approval of a product candidate for many
reasons. Despite the time and expense invested in the clinical development of product candidates, regulatory approval is never guaranteed.

The FDA and other regulatory agencies can delay, limit or deny approval of a product candidate for many reasons, including, but not limited to:

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the FDA or comparable foreign regulatory authorities may disagree with the trial design or implementation of our clinical trials, including proper use of
clinical trial methods and methods of data analysis;

an inability to establish sufficient data and information to demonstrate to the satisfaction of the FDA that a product candidate is safe and effective for an
indication;

the FDA may not accept clinical data from trials conducted by individual investigators or in countries where the standard of care is potentially different
from that of the United States;

the results of clinical trials may not meet the level of statistical significance required by the FDA for approval;

the FDA may disagree with the interpretation of data from preclinical studies or clinical trials;

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the  FDA  may  determine  that  our  manufacturing  processes  or  facilities  or  those  of  third-party  manufacturers  with  which  we  or  our  respective
collaborators currently contract for clinical supplies and plan to contract for commercial supplies do not satisfactorily comply with CGMPs; or

the approval policies or interpretation of regulations of the FDA may significantly change in a manner rendering the clinical data insufficient for approval
or the product characteristics or benefit-risk profile unfavorable for approval.

With respect to foreign markets, approval procedures vary among countries and, in addition to the aforementioned risks, can involve additional product testing,
administrative review periods and agreements with pricing authorities. In addition, rapid drug and biological development during the COVID-19 pandemic has
raised questions about the safety and efficacy of certain marketed pharmaceuticals and may result in increased cautiousness by the FDA and comparable foreign
regulatory  authorities  in  reviewing  new  pharmaceuticals  based  on  safety,  efficacy  or  other  regulatory  considerations  and  may  result  in  significant  delays  in
obtaining  regulatory  approvals. Any  delay  in  obtaining,  or  inability  to  obtain,  applicable  regulatory  approvals  would  prevent  us  from  commercializing  our
product candidates.

Regulatory  approval  for  our  product  candidates  by  the  FDA,  or  any  similar  regulatory  authorities  outside  the  United  States,  is  limited  to  those  specific
indications and conditions for which clinical safety and efficacy have been demonstrated.

Any regulatory approval is limited to the indications for use and related treatment of those specific diseases and indications set forth in the approval for which a
product is deemed to be safe and effective by the FDA, or other similar regulatory authorities outside the United States. In addition to the regulatory approval
required for new drug products, new formulations or indications for an approved product also require regulatory approval. If we are not able to obtain regulatory
approval for any desired future indications for our products, our ability to effectively market and sell our products may be reduced and our business may be
adversely affected.

While physicians may choose to prescribe drugs for uses that are not described in the product’s labeling and for uses that differ from those tested in clinical
studies  and  approved  by  the  regulatory  authorities  (“off-label  uses”),  our  ability  to  promote  the  products  is  limited  to  those  indications  that  are  specifically
approved by the FDA, or similar regulatory authorities outside the United States. Such off-label uses are common across medical specialties and may constitute
an  appropriate  treatment  for  some  patients  in  certain  circumstances.  Regulatory  authorities  in  the  U.S.  generally  do  not  regulate  practice  of  medicine  or  the
behavior of physicians in their choice of treatments. Regulatory authorities do, however, restrict communications by pharmaceutical companies on the promotion
of  off-label  use.  If  our  promotional  activities  fail  to  comply  with  these  regulations  or  guidelines,  we  may  be  subject  to  compliance  or  enforcement  actions,
including Warning Letters, by these authorities. In addition, our failure to follow FDA laws, regulations and guidelines relating to promotion and advertising
may cause the FDA to suspend or withdraw an approved product from the market, request a recall or institute fines or penalties, or could result in disgorgement
of money, operating restrictions, corrective advertising, injunctions or criminal prosecution, any of which could harm our business.

If  any  of  our  product  candidates  is  approved  and  we  or  our  contract  manufacturer(s)  fail  to  produce  the  product,  or  components  of  the  product,  in  the
volumes that we require on a timely basis, or fail to comply with stringent regulations applicable to pharmaceutical drug manufacturers, we may face delays
in the commercialization of our product candidates or be unable to meet market demand, and may lose potential revenues.

The  manufacture  of  pharmaceutical  products  requires  significant  expertise  and  capital  investment,  including  the  development  of  advanced  manufacturing
techniques  and  process  controls,  and  the  use  of  specialized  processing  equipment.  We  may  enter  into  development  and  supply  agreements  with  contract
manufacturers for the completion of pre-commercialization manufacturing development activities and, if approved, the manufacture of commercial supplies for
one or more of our product candidates. Any termination or disruption of our relationships with our contract manufacturers may materially harm our business and
financial condition and frustrate any commercialization efforts for each respective product candidate.

All  of  our  contract  manufacturers  must  comply  with  strictly  enforced  federal,  state  and  foreign  regulations,  including  current  good  manufacturing  practice
(“cGMP”) requirements enforced by the FDA through its establishment inspection program. We are required by law to establish adequate oversight and control
over raw materials, components and finished products furnished by our third-party suppliers and contract manufacturers, but we have little control over their
compliance  with  these  regulations.  Any  failure  to  comply  with  applicable  regulations  may  result  in  fines  and  civil  penalties,  suspension  of  production,
restrictions on imports and exports, suspension or delay in product approval, product seizure or recall, or withdrawal of product approval, and would limit the
availability  of  our  product  and  customer  confidence  in  our  product. Any  manufacturing  defect  or  error  discovered  after  products  have  been  produced  and
distributed could result in even more significant consequences, including costly recalls, re-stocking costs, damage to our reputation and potential for product
liability claims.

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If  the  contract  manufacturers  upon  whom  we  may  rely  to  manufacture  one  or  more  of  our  product  candidates,  and  any  future  product  candidate  we  may  in-
license, fails to deliver the required commercial quantities on a timely basis at commercially reasonable prices, we would likely be unable to meet demand for
our products and we would lose potential revenues.

If  serious  adverse  or  unacceptable  side  effects  are  identified  during  the  development  of  one  or  more  of  our  product  candidates  or  any  future  product
candidate, we may need to abandon or limit our development of some of our product candidates.

If one or more of our product candidates or any future product candidate are associated with undesirable side effects or adverse events in clinical trials or have
characteristics that are unexpected, we may need to abandon their development or limit development to more narrow uses or subpopulations in which the adverse
events, undesirable side effects or other characteristics are less prevalent, less severe or more acceptable from a risk-benefit perspective. In our industry, many
compounds that initially showed promise in early stage testing have later been found to cause serious adverse events that prevented further development of the
compound.  In  the  event  that  our  clinical  trials  reveal  a  high  or  unacceptable  severity  and  prevalence  of  adverse  events,  our  trials  could  be  suspended  or
terminated,  and  the  FDA  or  comparable  foreign  regulatory  authorities  could  order  us  to  cease  further  development  or  deny  approval  of  one  or  more  of  our
product candidates or any future product candidate for any or all targeted indications. The FDA could also issue a letter requesting additional data or information
prior to making a final decision regarding whether or not to approve a product candidate. The number of requests for additional data or information issued by the
FDA in recent years has increased and has resulted in substantial delays in the approval of several new drugs. Adverse events or undesirable side effects caused
by one or more of our product candidates or any future product candidate could also result in the inclusion of unfavorable information in our product labeling or
in  denial  of  regulatory  approval  by  the  FDA  or  other  regulatory  authorities  for  any  or  all  targeted  indications,  which  would,  in  turn,  prevent  us  from
commercializing  and  generating  market  acceptance  and  revenues  from  the  sale  of  that  product  candidate. Adverse  events  or  side  effects  could  affect  patient
recruitment or the ability of enrolled patients to complete the trial and could result in potential product liability claims.

Additionally, if one or more of our product candidates or any future product candidate receives marketing approval and we or others later identify undesirable
side effects caused by this product, a number of potentially significant negative consequences could result, including:

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regulatory authorities may require the addition of unfavorable labeling statements, including specific warnings , black box warnings, adverse reactions,
precautions, and/or contraindications;

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regulatory authorities may suspend or withdraw their approval of the product, and/or require it to be removed from the market;

● we may be required to change the way the product is administered, conduct additional clinical trials or change the labeling of the product; or

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our reputation may suffer.

Any of these events could prevent us from achieving or maintaining market acceptance of any of our product candidates or any future product candidate or could
substantially increase our commercialization costs and expenses, which in turn could delay or prevent us from generating significant revenues, or any revenues,
from its sale.

Even  if  one  or  more  of  our  product  candidates  receives  regulatory  approval,  it  and  any  other  products  we  may  market  will  remain  subject  to  substantial
regulatory scrutiny.

If one or more of our product candidates that we may license or acquire is approved, the approved product candidate will be subject to ongoing requirements and
review  by  the  FDA  and  other  regulatory  authorities.  These  requirements  include  labeling,  packaging,  storage,  advertising,  promotion,  record-keeping  and
submission of safety and other post-market information and reports, registration and listing requirements, cGMP requirements relating to manufacturing, quality
control,  quality  assurance  and  corresponding  maintenance  of  records  and  documents,  requirements  regarding  the  distribution  of  samples  to  physicians  and
recordkeeping of the drug, and requirements regarding our presentations to and interactions with health care professionals.

The FDA, or other regulatory authorities, may also impose requirements for costly post-marketing studies or clinical trials and surveillance to monitor the safety
or efficacy of the product. The FDA and other applicable regulatory authorities closely regulates the post-approval marketing and promotion of drugs to ensure
drugs are marketed only for the approved indications and in accordance with the provisions of the approved labeling. The FDA and other applicable regulatory
authorities impose stringent restrictions on manufacturers’ communications regarding off-label use and if we do not market our products for only their approved
indications, we may be subject to enforcement action

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for off-label marketing. Violations of the FDCA relating to the promotion of prescription drugs may lead to investigations, civil claims, and/or criminal charges
alleging violations of federal and state health care fraud and abuse laws, as well as state consumer protection laws.

In addition, later discovery of previously unknown adverse events or other problems with our products, manufacturers or manufacturing processes, or failure to
comply with regulatory requirements, may yield various results, including:

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restrictions on such products, operations, manufacturers or manufacturing processes;

restrictions on the labeling or marketing of a product;

restrictions on product distribution or use;

requirements to conduct post-marketing studies or clinical trials;

● warning letters, untitled letters, import alerts, and/or inspection observations;

● withdrawal of the products from the market;

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refusal to approve pending applications or supplements to approved applications that we submit;

recall of products;

fines, restitution or disgorgement of profits;

suspension or withdrawal of marketing or regulatory approvals;

suspension of any ongoing clinical trials;

refusal to permit the import or export of our products;

product seizure; or

Injunctions, consent decrees, and/or the imposition of civil or criminal penalties.

The FDA’s policies may change, and additional government regulations may be enacted that could prevent, limit or delay regulatory approval of our product
candidates, or negatively affect those products for which we may have already received regulatory approval, if any. If we are slow or unable to adapt to changes
in  existing  requirements  or  the  adoption  of  new  requirements  or  policies,  or  if  we  are  not  able  to  maintain  regulatory  compliance,  we  may  be  subject  to  the
various actions listed above, including losing any marketing approval that we may have obtained.

We will need to obtain FDA approval of any proposed product brand names, and any failure or delay associated with such approval may adversely impact
our business.

A  pharmaceutical  product  cannot  be  marketed  in  the  U.S.  or  other  countries  until  we  have  completed  a  rigorous  and  extensive  regulatory  review  process,
including approval of a brand name. Any brand names we intend to use for our product candidates will require approval from the FDA regardless of whether we
have secured a formal trademark registration from the USPTO. The FDA typically conducts a review of proposed product brand names, including an evaluation
of  the  potential  for  confusion  with  other  product  names.  The  FDA  may  also  object  to  a  product  brand  name  if  it  believes  the  name  inappropriately  implies
medical  claims.  If  the  FDA  objects  to  any  of  our  proposed  product  brand  names,  we  may  be  required  to  adopt  an  alternative  brand  name  for  our  product
candidates.  If  we  adopt  an  alternative  brand  name,  we  would  lose  the  benefit  of  our  existing  trademark  applications  for  such  product  candidate  and  may  be
required to expend significant additional resources in an effort to identify a suitable product brand name that would qualify under applicable trademark laws, not
infringe the existing rights of third parties and be acceptable to the FDA. We may be unable to build a successful brand identity for a new trademark in a timely
manner or at all, which would limit our ability to commercialize our product candidates.

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Public concern regarding the safety of drug products could delay or limit our ability to obtain regulatory approval, result in the inclusion of unfavorable
information in our labeling, or require us to undertake other activities that may entail additional costs.

In light of widely publicized events concerning the safety risk of certain drug products, the FDA, members of the U.S. Congress, the Government Accountability
Office, medical professionals and the general public have raised concerns about potential drug safety issues. These events have resulted in the withdrawal of drug
products,  revisions  to  drug  labeling  that  further  limit  use  of  the  drug  products  and  the  establishment  of  risk  management  programs.  The  Food  and  Drug
Administration Amendments Act of 2007, or FDAAA, grants significant expanded authority to the FDA, much of which is aimed at improving the safety of drug
products  before  and  after  approval.  In  particular,  the  new  law  authorizes  the  FDA  to,  among  other  things,  require  post-approval  studies  and  clinical  trials,
mandate  changes  to  drug  labeling  to  reflect  new  safety  information  and  require  risk  evaluation  and  mitigation  strategies  for  certain  drugs,  including  certain
currently  approved  drugs.  It  also  significantly  expands  the  federal  government’s  clinical  trial  registry  and  results  databank,  which  we  expect  will  result  in
significantly increased government oversight of clinical trials. Under the FDAAA, companies that violate these and other provisions of the new law are subject
to substantial civil monetary penalties, among other regulatory, civil and criminal penalties. The increased attention to drug safety issues may result in a more
cautious approach by the FDA in its review of data from our clinical trials. Data from clinical trials may receive greater scrutiny, particularly with respect to
safety, which may make the FDA or other regulatory authorities more likely to require additional preclinical studies or clinical trials. If the FDA requires us to
conduct additional preclinical studies or clinical trials prior to approving any of our product candidates, our ability to obtain approval of this product candidate
will be delayed. If the FDA requires us to provide additional clinical or preclinical data following the approval of any of our product candidates, the indications
for which this product candidate is approved may be limited or there may be specific warnings or limitations on dosing, and our efforts to commercialize our
product candidates may be otherwise adversely impacted.

If  we  experience  delays  or  difficulties  in  the  enrollment  of  patients  in  clinical  trials,  our  receipt  of  necessary  regulatory  approvals  could  be  delayed  or
prevented.

We may not be able to initiate or continue clinical trials for one or more of our product candidates if we are unable to locate and enroll a sufficient number of
eligible patients to participate in these trials as required by the FDA or similar regulatory authorities outside the United States. Some of our competitors have
ongoing clinical trials for product candidates that treat the same indications that we are targeting for our product candidates, and patients who would otherwise
be  eligible  for  our  clinical  trials  may  instead  enroll  in  clinical  trials  of  our  competitors’  product  candidates. Available  therapies  for  the  indications  we  are
pursuing can also affect enrollment in our clinical trials. Patient enrollment is affected by other factors including, but not necessarily limited to:

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the severity of the disease under investigation;

the eligibility criteria for the study in question;

the perceived risks and benefits of the product candidate under study;

the efforts to facilitate timely enrollment in clinical trials;

the patient referral practices of physicians;

the number of clinical trials sponsored by other companies for the same patient population;

the ability to monitor patients adequately during and after treatment; and

the proximity and availability of clinical trial sites for prospective patients.

Our inability to enroll a sufficient number of patients for our clinical trials would result in significant delays and could require us to abandon one or more clinical
trials altogether. Enrollment delays in our clinical trials may result in increased development costs for our product candidates or future product candidates, which
would cause the value of our company to decline and limit our ability to obtain additional financing.

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If  our  competitors  develop  treatments  for  any  of  our  product  candidates’  target  indications  and  those  competitor  products  are  approved  more  quickly,
marketed more successfully or demonstrated to be more effective, the commercial opportunity for our product candidate will be reduced or eliminated.

The biotechnology and pharmaceutical industries are subject to rapid and intense technological change. We face, and will continue to face, competition in the
development and, if approved, marketing of our product candidates from academic institutions, government agencies, research institutions and biotechnology
and  pharmaceutical  companies.  There  can  be  no  assurance  that  developments  by  others  will  not  render  one  or  more  of  our  product  candidates  obsolete  or
noncompetitive.  Furthermore,  new  developments,  including  the  development  of  other  drug  technologies  and  methods  of  preventing  the  incidence  of  disease,
occur in the pharmaceutical industry at a rapid pace. These developments may render one or more of our product candidates obsolete or noncompetitive.

Competitors may seek to develop alternative formulations that do not directly infringe on our in-licensed patent rights. The commercial opportunity for one or
more of our product candidates could be significantly harmed if competitors are able to develop alternative formulations outside the scope of our in-licensed
patents. Compared to us, many of our potential competitors have substantially greater:

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capital resources;

development resources, including personnel and technology;

clinical trial experience;

regulatory experience;

expertise in prosecution of intellectual property rights; and

● manufacturing, distribution and sales and marketing experience.

As a result of these factors, our competitors may obtain regulatory approval of their products more rapidly than we are able to or may obtain patent protection or
other intellectual property rights that limit our ability to develop or commercialize one or more of our product candidates. Our competitors may also develop
drugs that are more effective, safe, useful and less costly than ours and may be more successful than us in manufacturing and marketing their products. Smaller
or early-stage companies may also prove to be significant competitors, particularly through collaborative arrangements with large and established companies.
We  will  also  face  competition  from  these  third  parties  in  establishing  clinical  trial  sites,  in  patient  registration  for  clinical  trials,  and  in  identifying  and  in-
licensing new product candidates.

Further,  generic  therapies  are  typically  sold  at  lower  prices  than  branded  therapies  and  are  generally  preferred  by  hospital  formularies  and  managed  care
providers of health services. We anticipate that, if approved, our product candidates will face increasing competition in the form of generic versions of branded
products of competitors, including those that have lost or will lose their patent exclusivity. In the future, we may face additional competition from a generic form
of our own candidates when the patents covering them begin to expire, or earlier if the patents are successfully challenged. If we are unable to demonstrate to
physicians and payers that the key differentiating features of our product candidates translate to overall clinical benefit or lower cost of care, we may not be able
to compete with generic alternatives.

If any of our product candidates are successfully developed but do not achieve broad market acceptance among physicians, patients, healthcare payors and
the medical community, the revenues that any such product candidates generate from sales will be limited.

Even if our product candidates receive regulatory approval, they may not gain market acceptance among physicians, patients, healthcare payors and the medical
community. Coverage and reimbursement of our product candidates by third-party payors, including government payors, generally would also be necessary for
commercial success. The degree of market acceptance of any approved products would depend on a number of factors, including, but not necessarily limited to:

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the efficacy and safety as demonstrated in clinical trials;

the timing of market introduction of such product candidate as well as competitive products;

the clinical indications for which the product is approved;

acceptance by physicians, major operators of cancer clinics and patients of the product as a safe and effective treatment;

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the safety of such product candidates seen in a broader patient group, (i.e., based on actual use);

the availability, cost and potential advantages of alternative treatments, including less expensive generic drugs;

the availability of adequate reimbursement and pricing by third-party payors and government authorities;

changes in regulatory requirements by government authorities for our product candidates;

the relative convenience and ease of administration of the product candidate for clinical practices;

the  product  labeling  or  product  insert  required  by  the  FDA  or  regulatory  authority  in  other  countries,  including  any  contradictions,  warnings,  drug
interactions, or other precautions;

changes in the standard of care for the targeted indications for our product  candidate  or  future  product  candidates,  which  could  reduce  the  marketing
impact of any labeling or marketing claims that we could make following FDA approval;

the approval, availability, market acceptance and reimbursement for a companion diagnostic, if any;

the prevalence and severity of adverse side effects; and

the effectiveness of our sales and marketing efforts.

If any product candidate that we develop does not provide a treatment regimen that is as beneficial as, or is not perceived as being as beneficial as, the current
standard  of  care  or  otherwise  does  not  provide  patient  benefit,  that  product  candidate,  if  approved  for  commercial  sale  by  the  FDA  or  other  regulatory
authorities, likely will not achieve market acceptance. Our ability to effectively promote and sell any approved products will also depend on pricing and cost-
effectiveness, including our ability to produce a product at a competitive price and our ability to obtain sufficient third-party coverage or reimbursement. If any
product  candidate  is  approved  but  does  not  achieve  an  adequate  level  of  acceptance  by  physicians,  patients  and  third-party  payors,  our  ability  to  generate
revenues from that product would be substantially reduced. In addition, our efforts to educate the medical community and third-party payors on the benefits of
our product candidates may require significant resources, may be constrained by FDA rules and policies on product promotion, and may never be successful.

Reimbursement  may  be  limited  or  unavailable  in  certain  market  segments  for  our  product  candidates,  which  could  make  it  difficult  for  us  to  sell  our
products profitably.

There is significant uncertainty related to the third-party coverage and reimbursement of newly approved drugs. Such third-party payors include government
health programs such as Medicare, managed care providers, private health insurers and other organizations. We intend to seek approval to market our product
candidates in the U.S., the EU and other selected foreign jurisdictions. Market acceptance and sales of our product candidates in both domestic and international
markets will depend significantly on the availability of adequate coverage and reimbursement from third-party payors for any of our product candidates and may
be affected by existing and future health care reform measures. Government and other third-party payors are increasingly attempting to contain healthcare costs
by  limiting  both  coverage  and  the  level  of  reimbursement  for  new  drugs  and,  as  a  result,  they  may  not  cover  or  provide  adequate  payment  for  our  product
candidates. These payors may conclude that our product candidates are less safe, less effective or less cost-effective than existing or future introduced products,
and third-party payors may not approve our product candidates for coverage and reimbursement or may cease providing coverage and reimbursement for these
product candidates.

Obtaining coverage and reimbursement approval for a product from a government or other third-party payor is a time consuming and costly process that could
require  us  to  provide  to  the  payor  supporting  scientific,  clinical  and  cost-effectiveness  data  for  the  use  of  our  products.  We  may  not  be  able  to  provide  data
sufficient to gain acceptance with respect to coverage and reimbursement. If reimbursement of our future products is unavailable or limited in scope or amount,
or if pricing is set at unsatisfactory levels, we may be unable to achieve or sustain profitability.

In  some  foreign  countries,  particularly  in  the  EU,  the  pricing  of  prescription  pharmaceuticals  is  subject  to  governmental  control.  In  these  countries,  pricing
negotiations with governmental authorities can take considerable time after the receipt of marketing approval for a product candidate. To obtain reimbursement
or pricing approval in some countries, we may be required to conduct additional clinical trials that compare the cost-effectiveness of our product candidates to
other available therapies. If reimbursement of our product candidates is unavailable or limited in scope or amount in a particular country, or if pricing is set at
unsatisfactory levels, we may be unable to achieve or sustain profitability of our products in such country.

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If  we  are  unable  to  establish  sales,  marketing  and  distribution  capabilities  or  to  enter  into  agreements  with  third  parties  to  market  and  sell  our  product
candidates, we may be unsuccessful in commercializing our product candidates, if they are approved.

We currently do not have a marketing or sales organization for the marketing, sales and distribution of pharmaceutical products. In order to commercialize any
approved product candidate, we would need to build marketing, sales, distribution, managerial and other non-technical capabilities or arrange for third parties to
perform these services, and we may be unsuccessful in doing so. In the event of successful development and regulatory approval of any of our current or future
product candidates, we expect to build a targeted specialist sales force to market or co-promote the product. There are risks involved with establishing our own
sales, marketing and distribution capabilities. For example, recruiting and training a sales force is expensive and time consuming and could delay any product
launch. If the commercial launch of a product candidate for which we recruit a sales force and establish marketing capabilities is delayed or does not occur for
any reason, we would have prematurely or unnecessarily incurred these commercialization expenses. This may be costly, and our investment would be lost if we
cannot retain or reposition our sales and marketing personnel.

Factors that may inhibit our efforts to commercialize our products on our own include, but are not necessarily limited to:

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our inability to recruit, train and retain adequate numbers of effective sales and marketing personnel;

the inability of sales personnel to obtain access to physicians or persuade adequate numbers of physicians to prescribe any future products;

the lack of complementary or other products to be offered by sales personnel, which may put us at a competitive disadvantage from the perspective of
sales efficiency relative to companies with more extensive product lines; and

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unforeseen costs and expenses associated with creating our own sales and marketing organization.

We  face  potential  product  liability  exposure,  and  if  successful  claims  are  brought  against  us,  we  may  incur  substantial  liability  for  one  or  more  of  our
product candidates or a future product candidate we may license or acquire and may have to limit their commercialization.

The use of one or more of our product candidates and any future product candidate we may license or acquire in clinical trials and the sale of any products for
which we obtain marketing approval expose us to the risk of product liability claims. For example, we may be sued if any product we develop allegedly causes
injury or is found to be otherwise unsuitable during clinical testing, manufacturing, marketing or sale. Any such product liability claims may include allegations
of defects in manufacturing, defects in design, a failure to warn of dangers inherent in the product, negligence, strict liability or a breach of warranties. Product
liability claims might be brought against us by consumers, health care providers or others using, administering or selling our products. If we cannot successfully
defend ourselves against these claims, we will incur substantial liabilities. Regardless of merit or eventual outcome, liability claims may result in:

● withdrawal of clinical trial participants;

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suspension or termination of clinical trial sites or entire trial programs;

decreased demand for any product candidates or products that we may develop;

initiation of investigations by regulators;

impairment of our business reputation;

costs of related litigation;

substantial monetary awards to patients or other claimants;

loss of revenues;

reduced resources of our management to pursue our business strategy; and

the inability to commercialize our product candidate or future product candidates.

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We will obtain limited product liability insurance coverage for any and all of our upcoming clinical trials. However, our insurance coverage may not reimburse
us or may not be sufficient to reimburse us for any expenses or losses we may suffer. Moreover, insurance coverage is becoming increasingly expensive, and, in
the future, we may not be able to maintain insurance coverage at a reasonable cost or in sufficient amounts to protect us against losses due to liability. When
needed we intend to expand our insurance coverage to include the sale of commercial products if we obtain marketing approval for one or more of our product
candidates in development, but we may be unable to obtain commercially reasonable product liability insurance for any products approved for marketing. On
occasion, large judgments have been awarded in class action lawsuits based on drugs that had unanticipated side effects. A successful product liability claim or
series of claims brought against us could cause our stock price to fall and, if judgments exceed our insurance coverage, could decrease our cash and adversely
affect our business.

Product candidates, even if successfully developed and commercialized, may be effective only in combating certain specific types of cancer, and the market
for drugs designed to combat such cancer type(s) may be small and unprofitable.

There  are  many  different  types  of  cancer,  and  a  treatment  that  is  effective  against  one  type  of  cancer  may  not  be  effective  against  another.  CAR  T  or  other
technologies we pursue may only be effective in combating specific types of cancer but not others. Even if one or more of our products proves to be an effective
treatment against a given type of cancer, the number of patients suffering from such cancer may be small, in which case potential sales from a therapy designed
to combat such cancer would be limited.

Our gene therapy product candidates are based on a novel technology, which makes it difficult to predict the time and cost of product candidate development
and subsequently obtaining regulatory approval.

We have concentrated a portion of our therapeutic product research and development efforts on our gene therapy platform, and our future success depends, in
part, on the successful development of this therapeutic approach. There can be no assurance that any development problems we experience in the future related
to our gene therapy platform will not cause significant delays or unanticipated costs, or that such development problems can be solved. We may also experience
delays in developing a sustainable, reproducible and commercial-scale manufacturing process or transferring that process to commercial partners, which may
prevent us from completing our clinical studies or commercializing our products on a timely or profitable basis, if at all.

In addition, the clinical study requirements of the FDA, the European Medicines Agency, or EMA, and other regulatory agencies and the criteria these regulators
use to determine the safety and efficacy of a product candidate vary substantially according to the type, complexity, novelty and intended use and market of the
potential  products.  The  regulatory  approval  process  for  novel  product  candidates  such  as  ours  can  be  more  expensive  and  take  longer  than  for  other,  better
known  or  more  extensively  studied  pharmaceutical  or  other  product  candidates.  Currently,  a  limited  number  of  gene  therapy  products,  including  CAR  T
therapies, have been approved by the FDA, the EMA and the European Commission. Given the few precedents of approved gene therapy products, it is difficult
to  determine  how  long  it  will  take  or  how  much  it  will  cost  to  obtain  regulatory  approvals  for  our  product  candidates  in  the  United  States,  the  EU  or  other
jurisdictions. Approvals by the EMA and the European Commission may not be indicative of what the FDA may require for approval.

Regulatory requirements governing the development of gene therapy products have changed frequently and may continue to change in the future. The FDA has
established the Office of Tissues and Advanced Therapies within the Center for Biologics Evaluation and Research, or CBER, to consolidate the review of gene
therapy and related products, and to advise the CBER on its review. The FDA can put an investigational new drug application, or IND, on clinical hold if the
information in an IND is not sufficient to assess the risks in pediatric patients. Before a clinical study can begin at any institution, that institution’s IRB and its
Institutional  Biosafety  Committee  will  have  to  review  the  proposed  clinical  study  to  assess  the  safety  of  the  study.  Moreover,  serious  adverse  events  or
developments in clinical trials of gene therapy product candidates conducted by others may cause the FDA or other regulatory bodies to initiate a clinical hold on
our clinical trials or otherwise change the requirements for approval of any of our product candidates.

These  regulatory  review  agencies,  committees  and  advisory  groups  and  the  new  requirements  and  guidelines  they  promulgate  may  lengthen  the  regulatory
review process, require us to perform additional or larger studies, increase our development costs, lead to changes in regulatory positions and interpretations,
delay  or  prevent  approval  and  commercialization  of  these  treatment  candidates  or  lead  to  significant  post-approval  studies,  limitations  or  restrictions. As  we
advance  our  product  candidates,  we  will  be  required  to  consult  with  these  regulatory  and  advisory  groups  and  comply  with  applicable  requirements  and
guidelines. If we fail to do so, we may be required to delay or discontinue development of our product candidates. Delay or failure to obtain, or unexpected costs
in  obtaining,  the  regulatory  approval  necessary  to  bring  a  potential  product  to  market  could  decrease  our  ability  to  generate  sufficient  product  revenue  to
maintain our business.

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Negative public opinion and increased regulatory scrutiny of the therapies that underpin many of our product candidates may damage public perception of
our product candidates or adversely affect our ability to conduct our business or obtain regulatory approvals for our product candidates.

Public perception may be influenced by claims that one or more of the therapies underpinning our product candidates, including without limitation gene therapy,
is unsafe, and such therapy may not gain the acceptance of the public or the medical community. In particular, the success of our gene therapy platforms will
depend  upon  physicians  specializing  in  the  treatment  of  those  diseases  that  our  product  candidates  target  prescribing  treatments  that  involve  the  use  of  our
product candidates in lieu of, or in addition to, existing treatments with which they are already familiar and for which greater clinical data may be available.
More restrictive government regulations or negative public opinion would have a negative effect on our business or financial condition and may delay or impair
the development and commercialization of our product candidates or demand for any products we may develop. Adverse events in our clinical trials, even if not
ultimately attributable to our product  candidates,  and  the  resulting  publicity,  could  lead  to  increased  governmental  regulation,  unfavorable  public  perception,
potential  regulatory  delays  in  the  testing  or  approval  of  our  potential  product  candidates,  stricter  labeling  requirements  for  those  product  candidates  that  do
obtain approval and/or a decrease in demand for any such product candidates. Concern about environmental spread of our products, whether real or anticipated,
may also hinder the commercialization of our products.

Risks Related to Reliance on Third Parties

We  rely,  and  expect  to  continue  to  rely,  on  third  parties  to  conduct  our  preclinical  studies  and  clinical  trials,  and  those  third  parties  may  not  perform
satisfactorily, including failing to meet deadlines for the completion of such trials or complying with applicable regulatory requirements.

We rely on our licensors to conduct some of our preclinical studies and some of our clinical trials for our product candidates and for future product candidates,
and we rely on third-party contract research organizations and site management organizations to conduct most of the remainder of our preclinical studies and all
the rest of our clinical trials. We expect to continue to rely on third parties, such as our licensors, contract research organizations, site management organizations,
clinical data management organizations, medical institutions and clinical investigators, to conduct some of our preclinical studies and all of our clinical trials.
The  agreements  with  these  third  parties  might  terminate  for  a  variety  of  reasons,  including  a  failure  to  perform  by  the  third  parties.  If  we  need  to  enter  into
alternative arrangements, that could delay our product development activities.

Our reliance on these third parties for research and development activities reduces our control over these activities but does not relieve us of our responsibilities.
For  example,  we  remain  responsible  for  ensuring  that  each  of  our  preclinical  studies  and  clinical  trials  are  conducted  in  accordance  with  the  general
investigational plan and protocols for the trial and for ensuring that our preclinical studies are conducted in accordance with good laboratory practices (“GLPs”)
as appropriate. Moreover, the FDA requires us to comply with standards, commonly referred to as good clinical practices (“GCPs”) for conducting, recording
and reporting the results of clinical trials to assure that data and reported results are credible and accurate and that the rights, integrity and confidentiality of trial
participants are protected. Regulatory authorities enforce these requirements through periodic inspections of trial sponsors, clinical investigators and trial sites. If
we  or  any  of  our  CROs  fail  to  comply  with  applicable  GCPs,  the  clinical  data  generated  in  our  clinical  trials  may  be  deemed  unreliable  and  the  FDA  or
comparable foreign regulatory authorities may require us to perform additional clinical trials before approving our marketing applications. We cannot assure you
that upon inspection by a regulatory authority, such regulatory authority will determine that any of our clinical trials complies with GCP regulations. In addition,
our  clinical  trials  must  be  conducted  with  product  produced  under  cGMP  regulations.  Our  failure  to  comply  with  these  regulations  may  require  us  to  repeat
clinical  trials,  which  would  delay  the  regulatory  approval  process.  We  also  are  required  to  register  ongoing  clinical  trials  and  post  the  results  of  completed
clinical trials on a government-sponsored database, ClinicalTrials.gov, within specified timeframes. Failure to do so can result in fines, adverse publicity and
civil and criminal sanctions.

The third parties with whom we have contracted to help perform our preclinical studies and/or clinical trials may also have relationships with other entities, some
of which may be our competitors. If these third parties do not successfully carry out their contractual duties, meet expected deadlines or conduct our preclinical
studies  or  clinical  trials  in  accordance  with  regulatory  requirements  or  our  stated  protocols,  we  will  not  be  able  to  obtain,  or  may  be  delayed  in  obtaining,
marketing approvals for our product candidates and will not be able to, or may be delayed in our efforts to, successfully commercialize our product candidates.

If any of our relationships with these third-party contract research organizations or site management organizations terminates, we may not be able to enter into
arrangements  with  alternative  contract  research  organizations  or  site  management  organizations  or  to  do  so  on  commercially  reasonable  terms.  Switching  or
adding  additional  contract  research  organizations  or  site  management  organizations  involves  additional  cost  and  requires  management  time  and  focus.  In
addition, there is a natural transition period when a new contract research organization or site management organization commences work. As a result, delays
could occur, which could compromise our ability to

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meet  our  desired  development  timelines.  Though  we  carefully  manage  our  relationships  with  our  contract  research  organizations  or  site  management
organizations, there can be no assurance that we will not encounter similar challenges or delays in the future. Forces beyond our control, including the impacts of
COVID-19, could disrupt the ability of our third-party CROs, site management organizations, clinical data management organizations, medical institutions, and
clinical investigators to conduct our preclinical studies and our clinical trials for our product candidates and for any future product candidate. For instance, the
developing situation in China and globally regarding the coronavirus disease outbreak has the potential to adversely impact our product development activities.
At this time, the impact of the coronavirus disease outbreak is not having a material adverse effect on our business, but no assurance can be given it will not in
the future if the situation persists.

We  are  currently  reliant  on  the  City  of  Hope  National  Medical  Center,  the  Fred  Hutchinson  Cancer  Research  Center,  St.  Jude  Children’s  Research
Hospital, and the University of Alabama at Birmingham for a substantial portion of our research and development efforts and the early clinical testing of
our product candidates.

A  substantial  portion  of  our  research  and  development  has  been  and  will  continue  to  be  conducted  by  COH,  Fred  Hutch,  St.  Jude,  and  UAB  pursuant  to  a
sponsored research agreement and/or clinical trial agreements with each of those parties. As a result, our future success is heavily dependent on the results of
research  and  development  efforts  of  Dr.  Stephen  Forman  and  his  laboratory  team  at  COH,  of  Dr.  Brian  Till  and  his  laboratory  team  at  Fred  Hutch,  of
Drs. Stephen Gottschalk and Ewelina Mamcarz at St. Jude, and of Dr. James M. Markert at UAB. We have limited control over the nature or timing of their
research and limited visibility into their day-to-day activities, and as a result can provide little assurance that their efforts will be successful.

We contract with third parties for the manufacture of our product candidates for preclinical and clinical testing and may also do so for commercialization, if
and when our product candidates are approved. This reliance on third parties increases the risk that we will not have sufficient quantities of our product
candidates  or  any  future  product  candidate  or  such  quantities  at  an  acceptable  cost,  which  could  delay,  prevent  or  impair  our  development  or
commercialization efforts.

We may rely on third-party manufacturers or third-party collaborators for the manufacture of commercial supply of one or more product candidates for which
our  collaborators  or  we  obtain  marketing  approval.  We  may  be  unable  to  establish  any  agreements  with  third-party  manufacturers  or  to  do  so  on  acceptable
terms. Even if we are able to establish agreements with third-party manufacturers, reliance on third-party manufacturers entails additional risks, including, but
not necessarily limited to:

●

reliance on the third party for regulatory compliance and quality assurance, while still being required by law to establish adequate oversight and control
over products furnished by that third party;

●

the possible breach of the manufacturing agreement by the third party;

● manufacturing  delays  if  our  third-party  manufacturers  are  unable  to  obtain  raw  materials  due  to  supply  chain  disruptions,  give  greater  priority  to  the
supply of other products over our product candidates or otherwise do not satisfactorily perform according to the terms of the agreement between us;

●

●

the possible misappropriation of our proprietary information, including our trade secrets and know-how; and

the possible termination or nonrenewal of the agreement by the third party at a time that is costly or inconvenient for us.

We  rely  on  our  third-party  manufacturers  to  produce  or  purchase  from  third-party  suppliers  the  materials  and  equipment  necessary  to  produce  our  product
candidates for our preclinical and clinical trials. Forces beyond our control, including the effects of the COVID-19 pandemic, could disrupt the global supply
chain and impact our or our third-party manufacturers’ ability to obtain raw materials or other products necessary to manufacture our product candidates. There
are a limited number of suppliers for raw materials and equipment that we use (or that are used on our behalf) to manufacture our drugs, and there may be a need
to assess alternate suppliers to prevent a possible disruption of the manufacture of the materials and equipment necessary to produce our product candidates for
our preclinical and clinical trials, and if approved, ultimately for commercial sale. We do not have any control over the process or timing of the acquisition of
these raw materials or equipment by our third-party manufacturers. Any significant delay in the supply of a product candidate, or the raw material components
thereof, for an ongoing preclinical or clinical trial due to the need to replace a third-party manufacturer could considerably delay completion of our preclinical or
clinical trials, product testing and potential regulatory approval of our product candidates. If our manufacturers or we are unable to purchase these raw materials
or  equipment  after  regulatory  approval  has  been  obtained  for  our  product  candidates,  the  commercial  launch  of  our  product  candidates  would  be  delayed  or
there would be a shortage in supply, which would impair our ability to generate revenues from the sale of our product candidates.

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The facilities used by contract manufacturers to potentially manufacture our product candidates must be approved by the FDA pursuant to inspections that will
be conducted after we submit an NDA or BLA to the FDA. We are required by law to establish adequate oversight and control over raw materials, components
and finished products furnished by our contract manufacturers, but we do not control  the  day-to-day  manufacturing  operations  of,  and  are  dependent  on,  the
contract manufacturers for compliance with cGMP regulations for manufacture of our product candidates. Third-party manufacturers may not be able to comply
with the cGMP regulations or similar regulatory requirements outside the United States. Our failure, or the failure of our third-party manufacturers, to comply
with applicable regulations could result in sanctions being imposed on us, including clinical holds, fines, injunctions, restrictions on imports and exports, civil
penalties,  delays,  suspension  or  withdrawal  of  approvals,  license  revocation,  seizures  or  recalls  of  product  candidates  or  products,  operating  restrictions  and
criminal prosecutions, any of which could significantly and adversely affect supplies of our products.

One or more of the product candidates that we may develop may compete with other product candidates and products for access to manufacturing facilities.
There are a limited number of manufacturers that operate under cGMP regulations and that might be capable of manufacturing for us. Any performance failure
on the part of our existing or future manufacturers could delay clinical development or marketing approval. We do not currently have arrangements in place for
redundant supply. If our current contract manufacturers cannot perform as agreed, we may be required to replace such manufacturers. We may incur added costs
and delays in identifying and qualifying any replacement manufacturers. The DEA restricts the importation of a controlled substance finished drug product when
the same substance is commercially available in the United States, which could reduce the number of potential alternative manufacturers for one or more of our
product candidates.

Future  dependence  upon  others  for  the  manufacture  of  our  product  candidates  or  products  may  adversely  affect  our  future  profit  margins  and  our  ability  to
commercialize any products that may receive marketing approval on a timely and competitive basis.

We also expect to rely on other third parties to distribute drug supplies for our clinical trials. Any performance failure on the part of our distributors could delay
clinical  development  or  marketing  approval  of  our  product  candidates  or  commercialization  of  our  products,  if  approved,  producing  additional  losses  and
depriving us of potential product revenue.

We rely on third parties to conduct all aspects of our lentiviral vector production and these third parties may not perform satisfactorily.

We  do  not  independently  conduct  our  lentiviral  vector  production  and  we  currently  rely,  and  expect  to  continue  to  rely,  on  third  parties  with  respect  to  the
manufacture of these items.

Our reliance on these third parties for manufacturing lentiviral vector reduces our control over these activities but will not relieve us of our responsibility to
ensure compliance with all required regulations and study protocols. For products that we develop and commercialize, we will remain responsible for ensuring
that  each  of  our  IND-enabling  studies  and  clinical  studies  is  conducted  in  accordance  with  the  study  plan  and  protocols,  and  that  our  lentiviral  vectors  are
manufactured in accordance with GMP as applied in the relevant jurisdictions.

If  these  third  parties  do  not  successfully  carry  out  their  contractual  duties,  meet  expected  deadlines,  conduct  our  studies  in  accordance  with  regulatory
requirements or our stated study plans and protocols, or manufacture our lentiviral vectors in accordance with GMP, we will not be able to complete, or may be
delayed in completing, the preclinical and clinical studies and manufacturing process validation activities required to support future IND, market authorization
application and BLA submissions and approval of our product candidates, or to support commercialization of our products, if approved. Many of our agreements
with these third parties contain termination provisions that allow these third parties to terminate their relationships with us at any time. If we need to enter into
alternative arrangements, our product development and commercialization activities could be delayed.

We may be forced to enter into an agreement with a different manufacturer, which we may not be able to do on reasonable terms, if at all. In some cases, the
technical skills required to manufacture lentiviral vector for our drug product candidates may be unique or proprietary to the original manufacturer, and we may
have difficulty or there may be contractual restrictions prohibiting us from, transferring such skills to a back-up or alternate supplier, or we may be unable to
transfer such skills at all. Any of these events could lead to clinical study delays or failure to obtain marketing approval or impact our ability to successfully
commercialize our product or any future products. Some of these events could be the basis for FDA action, including injunction, recall, seizure or total or partial
suspension of production.

We rely on clinical data and results obtained by third parties that could ultimately prove to be inaccurate or unreliable.

As part of our strategy to mitigate development risk, we seek to develop product candidates with well-studied mechanisms of action, and we utilize biomarkers to
assess potential clinical efficacy early in the development process. This strategy necessarily relies upon clinical data and other results obtained by third parties
that may ultimately prove to be inaccurate or unreliable. Further, such clinical data and results

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may be based on products or product candidates that are significantly different from our product candidates or any future product candidate. If the third-party
data  and  results  we  rely  upon  prove  to  be  inaccurate,  unreliable  or  not  applicable  to  our  product  candidates  or  future  product  candidate,  we  could  make
inaccurate assumptions and conclusions about our product candidates and our research and development efforts could be compromised.

We may need to license certain intellectual property from third parties, and such licenses may not be available or may not be available on commercially
reasonable terms.

A third party may hold intellectual property, including patent rights that are important or necessary to the development and commercialization of our products. It
may  be  necessary  for  us  to  use  the  patented  or  proprietary  technology  of  third  parties,  who  may  or  may  not  be  interested  in  granting  such  a  license,  to
commercialize our products, in which case we would be required to obtain a license from these third parties on commercially reasonable terms, or our business
could be harmed, possibly materially.

Collaborative  relationships  with  third  parties  could  cause  us  to  expend  significant  resources  and  incur  substantial  business  risk  with  no  assurance  of
financial return.

Establishing  strategic  collaborations  is  difficult  and  time-consuming.  Our  discussions  with  potential  collaborators  may  not  lead  to  the  establishment  of
collaborations  on  favorable  terms,  if  at  all.  Potential  collaborators  may  reject  collaborations  based  upon  their  assessment  of  our  financial,  regulatory  or
intellectual property position. In addition, there has been a significant number of recent business combinations among large pharmaceutical companies that have
resulted in a reduced number of potential future collaborators. Even if we successfully establish new collaborations, these relationships may never result in the
successful  development  or  commercialization  of  product  candidates  or  the  generation  of  sales  revenue.  To  the  extent  that  we  enter  into  collaborative
arrangements,  the  related  product  revenues  are  likely  to  be  lower  than  if  we  directly  marketed  and  sold  products.  Such  collaborators  may  also  consider
alternative product candidates or technologies for similar indications that may be available to collaborate on and whether such a collaboration could be more
attractive than the one with us for any future product candidate.

Risks Relating to Legislation and Regulation Affecting the Biopharmaceutical and Other Industries

We  are  subject  to  new  legislation,  regulatory  proposals  and  managed  care  initiatives  that  may  increase  our  costs  of  compliance  and  adversely  affect  our
ability to market our products, obtain collaborators and raise capital.

Legislative  and  regulatory  changes  to  the  healthcare  systems  of  the  United  States  and  certain  foreign  countries  could  impact  our  ability  to  sell  our  products
profitably. In particular, the Medicare Prescription Drug, Improvement, and Modernization Act of 2003 (“MMA”) changed the way Medicare covers and pays
for pharmaceutical products by revising the payment methodology for many products reimbursed by Medicare, resulting in lower rates of reimbursement for
many types of drugs, and added a prescription drug benefit to the Medicare program that involves commercial plans negotiating drug prices for their members. In
addition, this law provided authority for limiting the number of drugs that will be covered in any therapeutic class. Cost reduction initiatives and other provisions
of this law and future laws could decrease the coverage and price that we will receive for any approved products. While the MMA only applies to drug benefits
for Medicare beneficiaries, private payors often follow Medicare coverage policy and payment limitations in setting their own payment rates. Therefore, any
limitations in reimbursement that results from the MMA may result in reductions in payments from private payors.

Since 2003, there have been several other legislative and regulatory changes to the coverage and reimbursement landscape for pharmaceuticals.  In March 2010,
the Patient Protection and Affordable Care Act, as amended by the Health Care and Education Reconciliation Act of 2010, collectively, the “Affordable Care
Act” or “ACA,” was enacted in 2010 and made significant changes to the United States’ healthcare system. The ACA and any revisions or replacements of that
Act, any substitute legislation, and other changes in the law or regulatory framework could have a material adverse effect on our business.

Among the provisions of the ACA of importance to our potential product candidates are:

●

●

an  annual,  nondeductible  fee  on  any  entity  that  manufactures,  or  imports  specified  branded  prescription  drugs  and  biological  products,  apportioned
among these entities according to their market share in certain government healthcare programs;

an increase in the statutory minimum rebates a manufacturer must pay under the Medicaid Drug Rebate Program to 23.1% and 13.0% of the average
manufacturer price for branded and generic drugs, respectively;

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●

●

●

●

●

●

●

●

●

expansion  of  healthcare  fraud  and  abuse  laws,  including  the  federal  False  Claims  Act  and  the  federal  Anti-Kickback  Statute,  new  government
investigative powers and enhanced penalties for non-compliance;

a  new  Medicare  Part  D  coverage  gap  discount  program,  in  which  manufacturers  must  agree  to  offer  point-of-sale  discounts  off  negotiated  prices  of
applicable brand drugs to eligible beneficiaries during their coverage gap period, as a condition for a manufacturer’s outpatient drugs to be covered under
Medicare Part D;

extension  of  a  manufacturer’s  Medicaid  rebate  liability  to  covered  drugs  dispensed  to  individuals  who  are  enrolled  in  Medicaid  managed  care
organizations;

expansion of eligibility criteria for Medicaid programs by, among other things, allowing states to offer Medicaid coverage to additional individuals and
by adding new mandatory eligibility categories for certain individuals with income at or below 138% of the federal poverty level, thereby potentially
increasing a manufacturer’s Medicaid rebate liability;

expansion of the entities eligible to enroll in the 340B Drug Pricing Program to include certain critical access hospitals, freestanding cancer hospitals,
rural referral centers, and sole community hospitals, but exempting certain drugs from the ceiling price requirements for these covered entities;

the new requirements under the federal Open Payments program and its implementing regulations;

a new requirement to annually report drug samples that manufacturers and distributors provide to physicians;

a new regulatory pathway for the approval of biosimilar biological products, all of which will impact existing government healthcare programs and will
result in the development of new programs; and

a new Patient-Centered Outcomes Research Institute to oversee, identify priorities in, and conduct comparative clinical effectiveness research, along with
funding for such research.

The Supreme Court upheld the ACA in the main challenge to the constitutionality of the law in 2012. Specifically, the Supreme Court held that the individual
mandate and corresponding penalty was constitutional because it would be considered a tax by the federal government. The Supreme Court also upheld federal
subsidies for purchasers of insurance through federally facilitated exchanges in a decision released in June 2015.

At  the  end  of  2017,  Congress  passed  the  Tax  Cuts  and  Jobs Act,  which  repealed  the  penalty  for  individuals  who  fail  to  maintain  minimum  essential  health
coverage as required by the ACA. Following this legislation, Texas and 19 other states filed a lawsuit alleging that the ACA is unconstitutional as the individual
mandate was repealed, undermining the legal basis for the Supreme Court’s prior decision. On December 14, 2018, a Texas federal district court judge issued a
ruling declaring that the ACA in its entirety is unconstitutional. Upon appeal, the Fifth Circuit upheld the district court’s ruling that the individual mandate is
unconstitutional. However, the Fifth Circuit remanded the case back to the district court to conduct a more thorough assessment of the constitutionality of the
entire ACA despite the individual mandate being unconstitutional. The Supreme Court agreed to hear the case on appeal from the Fifth Circuit on March 2, 2020
and held oral arguments on November 10, 2020. While this lawsuit has no immediate legal effect on the ACA and its provisions, this lawsuit is ongoing and the
outcome may have a significant impact on our business.

The Bipartisan Budget Act of 2018, the “BBA,” which set government spending levels for Fiscal Years 2018 and 2019, revised certain provisions of the ACA.
Specifically, beginning in 2019, the BBA increased manufacturer point-of-sale discounts off negotiated prices of applicable brand drugs in the Medicare Part D
coverage  gap  from  50%  to  70%,  ultimately  increasing  the  liability  for  brand  drug  manufacturers.  Further,  this  mandatory  manufacturer  discount  applied  to
biosimilars beginning in 2019.

The 116th Congress explored legislation intended to address the cost of prescription drugs. Notably, the major committees of jurisdiction in the Senate (Finance
Committee, Health, Education, Labor and Pensions Committee, and Judiciary Committee), marked up legislation intended to address various elements of the
prescription drug supply chain. Proposals include a significant overhaul of the Medicare Part D benefit design, addressing patent “loopholes”, and efforts to cap
the increase in drug prices. The House Energy and Commerce Committee approved drug-related legislation intended to increase transparency of drug prices and
also  curb  anti-competitive  behavior  in  the  pharmaceutical  supply  chain.  In  addition,  the  House  Ways  &  Means  Committee  approved  legislation  intended  to
improve drug price transparency, including for drug manufacturers to justify certain price increases. The 117th Congress convened on January 3, 2021, and could
reintroduce many of the bills targeting drug prices. While we cannot predict what proposals may ultimately become law, the elements under consideration could
significantly change the landscape in which the pharmaceutical market operates.

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The Senate Committee on Health, Education, Labor, and Pensions (HELP) advanced the Lower Health Care Costs Act of 2019. Among other things, the bill is
intended  to  reduce  costs  in  the  United  States  health  sector.  The  bill  revises  certain  requirements  to  expedite  the  approval  of  generics  and  biosimilars.  It  also
limits prices that pharmacy benefit managers may charge health insurers or enrollees for prescription drugs. Although this bill still needs to pass the full Senate
and House of Representatives, it is worth noting the wide-ranging effects it could have on the health care sector.

On December 12, 2019, the House of Representatives passed broad legislation (H.R. 3, the Elijah E. Cummings Lower Drug Costs Now Act) that would, among
other provisions, require the Department of Health and Human Services (“HHS”) to negotiate drug prices and impose price caps and restructure the Medicare
Part  D  benefit,  imposing  more  financial  responsibility  on  certain  drug  manufacturers.  Failure  by  a  manufacturer  to  reach  an  agreement  with  HHS  on  the
negotiated  price  could  result  in  significant  penalties  for  prescription  drug  manufacturers.  In  addition,  S.  2543, the  Prescription  Drug  Pricing  Reduction  Act
would also, among other provisions, restructure the Medicare Part D benefit, but it would not authorize direct negotiation by the federal government. While we
cannot  predict  what  proposals  may  ultimately  become  law,  the  elements  under  consideration  could  significantly  change  the  landscape  in  which  the
pharmaceutical market operates.

The Trump Administration took several regulatory steps to redirect ACA implementation. The HHS finalized a Medicare hospital payment reduction for Part B
drugs acquired through the 340B Drug Pricing Program.  Under the Trump Administration, HHS finalized several proposals aimed at lowering drug prices for
Medicare  beneficiaries  and  increasing  price  transparency.  For  example,  the  Trump  Administration  issued  an  interim  final  rule  on  November  27,  2020
implementing  a  “Most  Favored  Nation”  payment  model  for  Part  B  drugs  that  applies  international  reference  pricing  to  determine  reimbursement  for  certain
drugs  paid  by  Medicare  Part  B.  The  interim  final  rule  was  enjoined  by  federal  courts  prior  to  its  implementation  date  of  January  1,  2021,  and  the  lawsuit  is
ongoing. In addition, HHS, in conjunction with the FDA, finalized four pharmaceutical importation pathways in September 2020: (1) regulations establishing
importation of pharmaceuticals from Canada by wholesalers and pharmacists; (2)  FDA guidance permitting manufacturers to import their own pharmaceuticals
that were originally intended for marketing in other countries; (3) a request for proposals from private sector entities to import prescription drugs for personal use
under existing statutory authority; and (4) a request for proposals from private sector entities to reimport insulin under existing statutory authority. Further, on
November  11,  2020,  the  Trump  Administration  issued  a  final  rule  that  changes  the  permissible  structure  of  drug  rebates  and  discounts  between  drug
manufacturers and third-party payors (including pharmacy benefit managers that negotiate drug prices on behalf of such third-party payors). This final rule, often
referred to as the “Rebate Rule,” could have significant direct and indirect impacts on drug pricing in both government and commercial markets. With respect to
price  transparency,  the  Trump Administration  promulgated  regulations  that  require  hospitals  and  third-party  payors  to  disclose  prices  of  items  and  services,
which may impact negotiated rates in the commercial market.

On January 20, 2021, Joe Biden was inaugurated as the 46th president of the United States. As a presidential candidate, Mr. Biden indicated support for several
policies aimed at lowering drug prices, including government price negotiation, drug importation, international reference pricing, and price increase controls.
The incoming Biden Administration may continue, modify, or repeal many of the drug pricing policies proposed and finalized by the Trump Administration.
While we cannot predict which policies the Biden Administration may support and enforce, the policies finalized in the months prior to the beginning of Mr.
Biden’s  term,  if  continued,  could  significantly  change  the  landscape  in  which  the  pharmaceutical  market  operates  and  significantly  impact  our  ability  to
effectively market and sell our products.

There  likely  will  continue  to  be  legislative  and  regulatory  proposals  at  the  federal  and  state  levels  directed  at  broadening  the  availability  of  healthcare  and
containing or lowering the cost of healthcare products and services. We cannot predict the initiatives that may be adopted in the future. The continuing efforts of
the  government,  insurance  companies,  managed  care  organizations  and  other  payors  of  healthcare  services  to  contain  or  reduce  costs  of  healthcare  may
adversely affect:

●

●

●

●

●

the demand for any products for which we may obtain regulatory approval;

our ability to set a price that we believe is fair for our products;

our ability to generate revenues and achieve or maintain profitability;

the level of taxes that we are required to pay; and

the availability of capital.

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In addition, governments may impose price controls, which may adversely affect our future profitability. In January 2020, President Trump signed into law the
U.S.-Mexico-Canada (USMCA) trade deal into law. As enacted, there are no commitments with respect to biological product intellectual property rights or data
protection, which may create an unfavorable environment across these three countries.

We expect that the ACA, as well as other healthcare reform measures that may be adopted in the future, may result in more rigorous coverage criteria and in
additional  downward  pressure  on  the  price  that  we  receive  for  any  approved  drug.  Any  reduction  in  reimbursement  from  Medicare  or  other  government
healthcare programs may result in a similar reduction in payments from private payors. The implementation of cost containment measures or other healthcare
reforms may prevent us from being able to generate revenue, attain profitability or commercialize our drugs.

Legislative  and  regulatory  proposals  have  been  made  to  expand  post-approval  requirements  and  restrict  sales  and  promotional  activities  for  pharmaceutical
products. We cannot be sure whether additional legislative changes will be enacted, or whether the FDA regulations, guidance or interpretations will be changed,
or what the impact of such changes on the marketing approvals of our product candidates, if any, may be. In addition, increased scrutiny by the U.S. Congress of
the FDA’s approval process may significantly delay or prevent marketing approval, as well as subject us to more stringent product labeling and post-marketing
testing and other requirements.

We cannot predict the likelihood, nature or extent of government regulation that may arise from future legislation or administrative or executive action,
either in the United States or abroad.

We  cannot  predict  the  likelihood,  nature  or  extent  of  how  government  regulation  that  may  arise  from  future  legislation  or  administrative  or  executive  action
taken  by  the  U.S.  presidential  administration  may  impact  our  business  and  industry.  In  particular,  the  prior Administration    took  several  executive  actions,
specifically through rulemaking and guidance, that could impact the pharmaceutical business and industry. Shortly after taking office in January 2021, President
Biden announced that his Administration would be freezing a number of the prior Administration’s drug pricing reforms, while others remain subject to both
executive orders or regulatory changes issued by the Department of Health and Human Services.  A few of the major administrative actions include:

● On  October  30,  2019,  the  Trump Administration  issued  an  advanced  notice  of  proposed  rulemaking  (“ANPRM”)  entitled, International  Pricing  Index
Model  for  Medicare  Part  B  Drugs.  This ANPRM  was  intended  to  solicit  feedback  on  a  potential  proposal  to  align  United  States  drug  prices  in  the
Medicare Part B program with international prices. It also solicited public feedback on a policy that would allowing private-sector vendors to negotiate
prices, take title to drugs, and improve competition for hospital and physician business. Although this is only a notice for a potential rule, it signals the
Administration’s desire to regulatorily influence the United States drug pricing system that could adversely affect the industry.

● On  November  15,  2019,  CMS  issued  a  proposed  rule  entitled, Transparency  in  Coverage  and  finalized  the Calendar  Year  (“CY”)  2020  Outpatient
Prospective Payment System (“OPPS”) & Ambulatory Surgical Center Price Transparency Requirements for Hospitals to Make Standard Charges Rule.
Together the rules would increase price transparency through health plans and in hospitals. The affects may influence consumer purchasing habits in the
health care sector as a whole. Although the transparency provisions are not yet in effect and the hospital price transparency requirements are subject to
litigation, there could be implications for the industry related to drug pricing if or when it is enacted.

● On  November  18,  2019,  CMS  issued  a  proposed  rule  entitled, Medicaid  Fiscal  Accountability  Regulation  (“MFAR”).  The  proposed  rule  would
significantly impact states’ ability to finance their Medicaid programs. If finalized, the MFAR could force states to restructure their Medicaid financing
that could disincentivize or change state prescription drug purchasing behavior that would adversely impact the industry.

● On December 18, 2019, the FDA issued a proposed rule entitled, Importation of Prescription Drugs. The proposed rule would allow the importation of
certain  prescription  drugs  from  Canada.  If  finalized,  states  or  other  non-federal  government  entities  would  be  able  to  submit  importation  program
proposals to FDA for review and authorization. This proposed rule could also influence pricing practices in the United States.

● On January 30, 2020, CMS issued a state waiver option entitled, Health Adult Opportunity (“HAO”). The HAO would allow states to restructure benefits
and coverage policies for their Medicaid programs. The HAO will provide states administrative flexibilities in exchange for a capped federal share. The
cap on the federal share is commonly referred to as a “block grant.” Importantly, the HAO allows states to set formularies that align with Essential Health
Benefit requirements while still requiring manufacturers to participate in the Medicaid Rebate Program. Depending on utilization of the HAO by states, it
could impact the industry – especially if states elect to use a formulary.

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● On  December  2,  2020,  CMS  issued  a  final  rule  entitled, Modernizing  and  Clarifying  the  Physician  Self-Referral  Regulations  and  on  the  same  day  the
HHS  Office  of  Inspector  General  finalized  a  similar  rule,  entitled Revisions  to  Safe  Harbors  Under  the  Anti-Kickback  Statute,  and  Civil  Monetary
penalty Rules Regarding Beneficiary Inducements. The rules are an effort to reform regulations dealing with anti-kickback and self-referral laws. These
rules allow certain financial arrangements that would otherwise violate anti-kickback and self-referral laws for providers that are participating in value-
based  payment  arrangements.  The  rule  could  impact  drug  purchasing  behavior  to  ensure  providers  are  within  their  budget  and/or  restructure  existing
payment structures between providers and manufacturers.

As  with  any  change  in  the  Executive  Office,  and  particularly  with  respect  to  changes  from  a  Republican Administration  under  former  President  Trump  to  a
Democratic Administration under President Biden, we expect there to be significant changes to existing rules, regulations and policies, the enactment of new
Executive Orders and other immediate or iterative political, legislative and administrative changes, affecting the pharmaceutical industry.  We cannot predict the
likelihood, nature or extent of government regulation that may arise from future legislation or administrative or executive action, either in the United States, or
based on similar governmental changes in other countries.

Changes  in  funding  for  the  FDA  and  other  government  agencies  could  hinder  their  ability  to  hire  and  retain  key  leadership  and  other  personnel,  or
otherwise prevent new products and services from being developed or commercialized in a timely manner, which could negatively impact our business or the
business of our partners.

The ability of the FDA to review and approve new products can be affected by a variety of factors, including government budget and funding levels, ability to
hire and retain key personnel, ability to accept the payment of user fees, and statutory, regulatory, and policy changes. Average review times at the agency have
fluctuated in recent years as a result. In addition, government funding of other government agencies that fund research and development activities is subject to
the political process, which is inherently fluid and unpredictable.

Disruptions at the FDA and other agencies may also slow the time necessary for new drugs to be reviewed and/or approved by necessary government agencies,
which  would  adversely  affect  our  business  or  the  business  of  our  partners.  For  example,  over  the  last  several  years,  including  for  35  days  beginning  on
December 22, 2018, the U.S. government has shut down several times and certain regulatory agencies, such as the FDA, have had to furlough nonessential FDA
employees and stop routine activities. If a prolonged government shutdown occurs, it could significantly impact the ability of the FDA to timely review and
process our regulatory submissions, which could have a material adverse effect on our business. If the timing of FDA’s review and approval of new products is
delayed,  the  timing  of  our  or  our  partners’  development  process  may  be  delayed,  which  could  result  in  delayed  milestone  revenues  and  materially  harm  our
operations or business.

The  COVID-19  pandemic  has  caused  consideration  disruptions  at  the  FDA,  namely  with  respect  to  diverting  the  FDA’s  attention  and  resources  to  facilitate
vaccine  development  and  ensure  rapid  review  and  emergency  use  authorization  of  vaccines  intended  to  prevent  COVID-19.    Back  in  March,  Dr.  Janet
Woodcock, the Director of the FDA’s Center for Drug Evaluation and Research, temporarily stepped away from her role to focus on the therapeutic aspects of
Operation Warp Speed, a major reorganization intended to better align the FDA’s activities with the national effort to develop COVID-19 countermeasures.  Dr.
Woodcock  was  later  named  Acting  Commissioner  of  the  FDA  on  January  20,  2021.    These  changes  to  leadership,  enhanced  focus  on  COVID-19
countermeasures, and the reorganization and rededication or critical resources, both at the FDA and within similar governmental authorities across the world, are
likely to impact the ability of new products and services from being developed or commercialized in a timely manner

Our  current  and  future  relationships  with  customers  and  third-party  payors  in  the  United  States  and  elsewhere  may  be  subject,  directly  or  indirectly,  to
applicable anti-kickback, fraud and abuse, false claims, transparency, health information privacy and security and other healthcare laws and regulations,
which could expose us to  criminal  sanctions,  civil  penalties,  contractual  damages,  reputational  harm,  administrative  burdens  and  diminished  profits  and
future earnings.

Healthcare providers, physicians and third-party payors in the U.S. and elsewhere will play a primary role in the recommendation and prescription of any product
candidates for which we obtain marketing approval. Our future arrangements with third-party payors and customers may expose us to broadly applicable fraud
and abuse and other healthcare laws and regulations, including, without limitation, the federal Anti-Kickback Statute and the federal False Claims Act, which
may constrain the business or financial arrangements and relationships through which we sell, market and distribute any product candidates for which we obtain
marketing approval. In addition, we may be subject to transparency laws and patient privacy regulation by the federal and state governments and by governments
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which we conduct our business. The applicable federal, state and foreign healthcare laws and regulations that may affect our ability to operate include, but are
not necessarily limited to:

●

●

the federal Anti-Kickback Statute, which prohibits, among other things, persons from knowingly and willfully soliciting, offering, receiving or providing
remuneration, directly or indirectly, in cash or in kind, to induce or reward, or in return for, either the referral of an individual for, or the purchase, order
or recommendation of, any good or service, for which payment may be made under federal and state healthcare programs, such as Medicare and
Medicaid;

federal civil and criminal false claims laws and civil monetary penalty laws, including the federal False Claims Act, which impose criminal and civil
penalties, including civil whistleblower or qui tam actions, against individuals or entities for knowingly presenting, or causing to be presented, to the
federal government, including the Medicare and Medicaid programs, claims for payment that are false or fraudulent or making a false statement to avoid,
decrease or conceal an obligation to pay money to the federal government; the federal Health Insurance Portability and Accountability Act of 1996
(“HIPAA”), which imposes criminal and civil liability for executing a scheme to defraud any healthcare benefit program or making false statements
relating to healthcare matters;

● HIPAA,  as  amended  by  the  Health  Information  Technology  for  Economic  and  Clinical  Health  Act  of  2009  (“HITECH”),  and  their  respective
implementing  regulations,  which  impose  obligations  on  covered  healthcare  providers,  health  plans,  and  healthcare  clearinghouses,  as  well  as  their
business associates that create, receive, maintain or transmit individually identifiable health information for or on behalf of a covered entity, with respect
to safeguarding the privacy, security and transmission of individually identifiable health information;

●

●

the federal Open Payments program, which requires manufacturers of certain approved drugs, devices, biologics and medical supplies for which payment
is  available  under  Medicare,  Medicaid  or  the  Children’s  Health  Insurance  Program,  with  specific  exceptions,  to  report  annually  to  the  Centers  for
Medicare & Medicaid Services (“CMS”), information related to “payments or other transfers of value” made to physicians, which is defined to include
doctors,  dentists,  optometrists,  podiatrists  and  chiropractors,  and  teaching  hospitals  and  applicable  manufacturers  and  applicable  group  purchasing
organizations to report annually to CMS ownership and investment interests held by the physicians and their immediate family members. Data collection
began on August 1, 2013, with requirements for manufacturers to submit reports to CMS by March 31, 2014, and 90 days after the end each subsequent
calendar year. Disclosure of such information was made by CMS on a publicly available website beginning in September 2014 and is annually updated;
and

analogous state and foreign laws and regulations, such as state anti-kickback and false claims laws, which may apply to sales or marketing arrangements
and claims involving healthcare items or services reimbursed by non-governmental third-party payors, including private insurers; state and foreign laws
that  require  pharmaceutical  companies  to  comply  with  the  pharmaceutical  industry’s  voluntary  compliance  guidelines  and  the  relevant  compliance
guidance promulgated by the federal government or otherwise restrict payments that may be made to healthcare providers; state and foreign laws that
require  drug  manufacturers  to  report  information  related  to  payments  and  other  transfers  of  value  to  physicians  and  other  healthcare  providers  or
marketing expenditures; and state and foreign laws governing the privacy and security of health information in certain circumstances, many of which
differ from each other in significant ways and often are not preempted by HIPAA, thus complicating compliance efforts.

Efforts to ensure that our business arrangements with third parties will comply with applicable healthcare laws and regulations may involve substantial costs. It
is  possible  that  governmental  authorities  will  conclude  that  our  business  practices  may  not  comply  with  current  or  future  statutes,  regulations  or  case  law
involving applicable fraud and abuse or other healthcare laws and regulations. If our operations are found to be in violation of any of these laws or any other
governmental  regulations  that  may  apply  to  us,  we  may  be  subject  to  significant  civil,  criminal  and  administrative  penalties,  including,  without  limitation,
damages,  fines,  imprisonment,  exclusion  from  participation  in  government  healthcare  programs,  such  as  Medicare  and  Medicaid,  and  the  curtailment  or
restructuring of our operations, which could have a material adverse effect on our business. If any of the physicians or other healthcare providers or entities with
whom  we  expect  to  do  business,  including  our  collaborators,  is  found  not  to  be  in  compliance  with  applicable  laws,  it  may  be  subject  to  criminal,  civil  or
administrative sanctions, including exclusions from participation in government healthcare programs, which could also materially affect our business.

If we fail to comply with environmental, health and safety laws and regulations, we could become subject to fines or penalties or incur costs that could harm
our business.

We  are  subject  to  numerous  environmental,  health  and  safety  laws  and  regulations,  including  those  governing  laboratory  procedures  and  the  handling,  use,
storage, treatment and disposal of hazardous materials and wastes. Our operations involve the use of hazardous and flammable

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materials, including chemicals and biological materials. Our operations also produce hazardous waste products. We generally contract with third parties for the
disposal  of  these  materials  and  wastes.  We  cannot  eliminate  the  risk  of  contamination  or  injury  from  these  materials. Although  we  believe  that  the  safety
procedures for handling and disposing of these materials comply with the standards prescribed by these laws and regulations, we cannot eliminate the risk of
accidental contamination or injury from these materials. In the event of contamination or injury resulting from our use of hazardous materials, we could be held
liable for any resulting damages, and any liability could exceed our resources. We also could incur significant costs associated with civil or criminal fines and
penalties for failure to comply with such laws and regulations.

Although we maintain workers’ compensation insurance to cover us for costs and expenses, we may incur due to injuries to our employees resulting from the use
of hazardous materials, this insurance may not provide adequate coverage against potential liabilities. We do not maintain insurance for environmental liability
or toxic tort claims that may be asserted against us in connection with our storage or disposal of biological, hazardous or radioactive materials.

In addition, we may incur substantial costs in order to comply with current or future environmental, health and safety laws and regulations. These current or
future laws and regulations may impair our research, development or production efforts. Our failure to comply with these laws and regulations also may result in
substantial fines, penalties or other sanctions.

Risks Related to Intellectual Property and Potential Disputes Thereof

If  we  are  unable  to  obtain  and  maintain  sufficient  patent  protection  for  our  technology  and  products,  our  competitors  could  develop  and  commercialize
technology and products similar or identical to ours, and our ability to successfully commercialize our technology and products may be impaired.

Our  success  depends,  in  large  part,  on  our  ability  to  obtain  patent  protection  for  product  candidates  and  their  formulations  and  uses.  The  patent  application
process is subject to numerous risks and uncertainties, and there can be no assurance that we or our partners will be successful in obtaining patents or what the
scope of an issued patent may ultimately be. These risks and uncertainties include, but are not necessarily limited to, the following:

●

patent applications may not result in any patents being issued, or the scope of issued patents may not extend to competitive product candidates and their
formulations and uses developed or produced by others;

● our competitors, many of which have substantially greater resources than us or our partners, and many of which have made significant investments in
competing technologies, may seek, or may already have obtained, patents that may limit or interfere with our abilities to make, use, and sell potential
product candidates, file new patent applications, or may affect any pending patent applications that we may have;

● there may be significant pressure on the U.S. government and other international governmental bodies to limit the scope of patent protection both inside

and outside the United States for disease treatments that prove successful as a matter of public policy regarding worldwide health concerns; and

● countries other than the United States may have patent laws less favorable to patentees than those upheld by U.S. courts, allowing foreign competitors a

better opportunity to create, develop and market competing products.

In addition, patents that may be issued or in-licensed may be challenged, invalidated, modified, revoked, circumvented, found to be unenforceable, or otherwise
may  not  provide  any  competitive  advantage.  Moreover,  we  may  be  subject  to  a  third-party  pre-issuance  submission  of  prior  art  to  the  USPTO,  or  become
involved in opposition, derivation, reexamination, inter partes review, post-grant review or interference proceedings challenging our patent rights or the patent
rights of others. The costs of these proceedings could be substantial, and it is possible that our efforts to establish priority of invention would be unsuccessful,
resulting in a material adverse effect on our U.S. patent positions. An adverse determination in any such submission, patent office trial, proceeding or litigation
could reduce the scope of, render unenforceable, or invalidate, our patent rights, allow third parties to commercialize our technologies or products and compete
directly  with  us,  without  payment  to  us,  or  result  in  our  inability  to  manufacture  or  commercialize  products  without  infringing  third-party  patent  rights.  In
addition, if the breadth or strength of protection provided by our patents and patent applications is threatened, it could dissuade companies from collaborating
with us to license, develop or commercialize current or future product candidates. Third parties are often responsible for maintaining patent protection for our
product candidates, at our and their expense. If that party fails to appropriately prosecute and maintain patent protection for a product candidate, our abilities to
develop  and  commercialize  products  may  be  adversely  affected,  and  we  may  not  be  able  to  prevent  competitors  from  making,  using  and  selling  competing
products. Such a failure to properly protect intellectual

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property rights relating to any of our product candidates could have a material adverse effect on our financial condition and results of operations. In addition,
U.S. patent laws may change, which could prevent or limit us from filing patent applications or patent claims to protect products and/or technologies or limit the
exclusivity periods that are available to patent holders, as well as affect the validity, enforceability, or scope of issued patents.

We and our licensors also rely on trade secrets and proprietary know-how to protect product candidates. Although we have taken steps to protect our and their
trade  secrets  and  unpatented  know-how,  including  entering  into  confidentiality  and  non-use  agreements  with  third  parties,  and  proprietary  information  and
invention assignment agreements with employees, consultants and advisers, third parties may still come upon this same or similar information independently.
Despite  these  efforts,  any  of  these  parties  may  also  breach  the  agreements  and  may  unintentionally  or  willfully  disclose  our  or  our  licensors’  proprietary
information, including our trade secrets, and we may not be able to identify such breaches or obtain adequate remedies. Enforcing a claim that a party illegally
disclosed or misappropriated a trade secret is difficult, expensive and time-consuming, and the outcome is unpredictable. In addition, some courts inside and
outside the United States are less willing or unwilling to protect trade secrets. Moreover, if any of our or our licensors’ trade secrets were to be lawfully obtained
or independently developed by a competitor, we and our licensors would have no right to prevent them, or those to whom they communicate it, from using that
technology or information to compete with us. If any of our or our licensors’ trade secrets were to be disclosed to or independently developed by a competitor,
our competitive positions would be harmed.

The patent prosecution process is expensive and time-consuming, and we may not be able to file and prosecute all necessary or desirable patent applications at a
reasonable  cost  or  in  a  timely  manner.  It  is  also  possible  that  we  will  fail  to  identify  any  patentable  aspects  of  our  research  and  development  output  and
methodology, and, even if we do, an opportunity to obtain patent protection may have passed. Given the uncertain and time-consuming process of filing patent
applications and prosecuting them, it is possible that our product(s) or process(es) originally covered by the scope of the patent application may have changed or
been modified, leaving our product(s) or process(es) without patent protection. If our licensors or we fail to obtain or maintain patent protection or trade secret
protection for one or more product candidates or any future product candidate we may license or acquire, third parties may be able to leverage our proprietary
information  and  products  without  risk  of  infringement,  which  could  impair  our  ability  to  compete  in  the  market  and  adversely  affect  our  ability  to  generate
revenues  and  achieve  profitability.  Moreover,  should  we  enter  into  other  collaborations  we  may  be  required  to  consult  with  or  cede  control  to  collaborators
regarding the prosecution, maintenance and enforcement of licensed patents. Therefore, these patents and applications may not be prosecuted and enforced in a
manner consistent with the best interests of our business.

The  patent  position  of  biotechnology  and  pharmaceutical  companies  generally  is  highly  uncertain,  involves  complex  legal  and  factual  questions  and  has  in
recent years been the subject of much litigation. In addition, no consistent policy regarding the breadth of claims allowed in pharmaceutical or biotechnology
patents has emerged to date in the U.S. The patent situation outside the U.S. is even more uncertain. The laws of foreign countries may not protect our rights to
the same extent as the laws of the U.S., and we may fail to seek or obtain patent protection in all major markets. For example, European patent law restricts the
patentability of methods of treatment of the human body more than U.S. law does. Publications of discoveries in the scientific literature often lag behind the
actual discoveries, and patent applications in the U.S. and other jurisdictions are typically not published until 18 months after a first filing, or in some cases not
at  all.  Therefore,  we  cannot  know  with  certainty  whether  we  or  our  licensors  were  the  first  to  make  the  inventions  claimed  in  patents  or  pending  patent
applications that we own or licensed, or that we or our licensors were the first to file for patent protection of such inventions. In the event that a third party has
also filed a U.S. patent application relating to our product candidates or a similar invention, depending upon the priority dates claimed by the competing parties,
we may have to participate in interference proceedings declared by the USPTO to determine priority of invention in the U.S. We might also become involved in
derivation proceedings in an event that a third party misappropriates one or more of our inventions and files their own patent application directed to such one or
more inventions. The costs of these proceedings could be substantial, and it is possible that our efforts to establish priority of invention (or that a third party
derived an invention from us) would be unsuccessful, resulting in a material adverse effect on our U.S. patent position. As a result, the issuance, scope, validity,
enforceability and commercial value of our patent rights are highly uncertain. Our pending and future patent applications may not result in patents being issued
which protect our technology or products, in whole or in part, or which effectively prevent others from commercializing competitive technologies and products.
Changes in either the patent laws or interpretation of the patent laws in the U.S. and other countries may diminish the value of our patents or narrow the scope of
our patent protection. For example, the federal courts of the U.S. have taken an increasingly dim view of the patent eligibility of certain subject matter, such as
naturally occurring nucleic acid sequences, amino acid sequences and certain methods of utilizing the same, which include their detection in a biological sample
and diagnostic conclusions arising from their detection. Such subject matter, which had long been a staple of the biotechnology and biopharmaceutical industry
to protect their discoveries, is now considered, with few exceptions, ineligible in the first instance for protection under the patent laws of the U.S. Accordingly,
we cannot predict the breadth of claims that may be allowed and remain enforceable in our patents or in those licensed from a third party.

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Even if our patent applications issue as patents, they may not issue in a form that will provide us with any meaningful protection, prevent competitors from
competing  with  us  or  otherwise  provide  us  with  any  competitive  advantage.  Our  competitors  may  be  able  to  circumvent  our  owned  or  licensed  patents  by
developing similar or alternative technologies or products in a non-infringing manner.

We also may rely on the regulatory period of market exclusivity for any of our biologic product candidates that are successfully developed and approved for
commercialization. Although this period in the United States is generally 12 years from the date of marketing approval (depending on the nature of the specific
product),  there  is  a  risk  that  the  U.S.  Congress  could  amend  laws  to  significantly  shorten  this  exclusivity  period.  Once  any  regulatory  period  of  exclusivity
expires, depending on the status of our patent coverage and the nature of the product, we may not be able to prevent others from marketing products that are
biosimilar to or interchangeable with our products, which would materially adversely affect our business.

We depend on our licensors to maintain and enforce the intellectual property covering certain of our product candidates. We have limited, if any, control
over the resources that our licensors can or will devote to securing, maintaining, and enforcing patents protecting our product candidates.

We depend on our licensors to protect the proprietary rights covering our product candidates and we have limited, if any, control over the amount or timing of
resources that they devote on our behalf, or the priority they place on, maintaining patent rights and prosecuting patent applications to our advantage. Moreover,
we have limited, if any, control over the strategies and arguments employed in the maintenance of patent rights and the prosecution of patent applications to our
advantage. Our licensors might become involved in disputes with one of their other licensees, and we or a portion of our licensed patent rights might become
embroiled in such disputes.

Our licensors, depending on the patent or application, are responsible for maintaining issued patents and prosecuting patent applications. We cannot be sure that
they will perform as required. Should they decide they no longer want to maintain any of the patents licensed to us, they are required to afford us the opportunity
to do so at our expense. If our licensors do not perform, and if we do not assume the maintenance of the licensed patents in sufficient time to make required
payments  or  filings  with  the  appropriate  governmental  agencies,  we  risk  losing  the  benefit  of  all  or  some  of  those  patent  rights.  Moreover,  and  possibly
unbeknownst to us, our licensors may experience serious difficulties related to their overall business or financial stability, and they may be unwilling or unable
to  continue  to  expend  the  financial  resources  required  to  maintain  and  prosecute  these  patents  and  patent  applications.  While  we  intend  to  take  actions
reasonably necessary to enforce our patent rights, we depend, in part, on our licensors to protect a substantial portion of our proprietary rights and to inform us of
the status of those protections and efforts thereto.

Our licensors may also be notified of alleged infringement and be sued for infringement of third-party patents or other proprietary rights. We may have limited,
if any, control or involvement over the defense of these claims, and our licensors could be subject to injunctions and temporary or permanent exclusionary orders
in the U.S. or other countries. Our licensors are not obligated to defend or assist in our defense against third-party claims of infringement. We have limited, if
any, control over the amount or timing of resources, if any, that our licensors devote on our behalf or the priority they place on defense of such third-party claims
of infringement.

Because of the uncertainty inherent in any patent or other litigation involving proprietary rights, we or our licensors may not be successful in defending claims of
intellectual property infringement alleged by third parties, which could have a material adverse effect on our results of operations. Regardless of the outcome of
any litigation, defending the litigation may be expensive, time-consuming and distracting to management.

Protecting our proprietary rights is difficult and costly, and we may be unable to ensure their protection.

The degree of future protection for our proprietary rights is uncertain, because legal means afford only limited protection and may not adequately protect our
rights or permit us to gain or keep our competitive advantage, in addition to being costly and time consuming to undertake. For example:

●

●

●

our licensors might not have been the first to make the inventions covered by each of our pending patent applications and issued patents;

our licensors might not have been the first to file patent applications for these inventions;

others may independently develop similar or alternative technologies or duplicate our product candidates or any future product candidate technologies;

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●

●

●

it is possible that none of the pending patent applications licensed to us will result in issued patents;

the scope of our issued patents may not extend to competitive products developed or produced by others;

the issued patents covering our product candidates or any future product candidate may not provide a basis for market exclusivity for active products,
may not provide us with any competitive advantages, or may be challenged by third parties;

● we may not develop additional proprietary technologies that are patentable; or

●

intellectual property rights of others may have an adverse effect on our business.

We  may  become  involved  in  lawsuits  to  protect  or  enforce  our  patents  or  other  intellectual  property,  which  could  be  expensive,  time  consuming  and
unsuccessful, and an unfavorable outcome in any litigation would harm our business.

Competitors may infringe our issued patents or other intellectual property. To counter infringement or unauthorized use, we may be required to file one or more
actions for patent infringement, which can be expensive and time consuming. Any claims we assert against accused infringers could provoke these parties to
assert counterclaims against us alleging that we infringe their patents; or provoke those parties to petition the USPTO to institute inter partes review against the
asserted patents, which may lead to a finding that all or some of the claims of the patent are invalid. In addition, in a patent infringement proceeding, a court may
decide that a patent of ours is invalid or unenforceable, in whole or in part, construe the patent’s claims narrowly or refuse to stop the other party from using the
technology at issue on the grounds that our patents do not cover the technology in question or as a matter of public policy. An adverse result in any litigation
proceeding could put one or more of our patents at risk of being invalidated, rendered unenforceable, or interpreted narrowly. Furthermore, adverse results on
U.S. patents may affect related patents in our global portfolio.

If we or our licensors are sued for infringing intellectual property rights of third parties, it will be costly and time consuming, and an unfavorable outcome
in that litigation would have a material adverse effect on our business.

Our  success  also  depends  on  our  ability,  and  the  abilities  of  any  of  our  respective  current  or  future  collaborators,  to  develop,  manufacture,  market  and  sell
product candidates without infringing the proprietary rights of third parties. Numerous U.S. and foreign issued patents and pending patent applications, which
are owned by third parties, exist in the fields in which we are developing products, some of which may be directed at claims that overlap with the subject matter
of our or our licensors’ intellectual property. Because patent applications can take many years to issue, there may be currently pending applications, unknown to
us, which may later result in issued patents that our product candidates or proprietary technologies may infringe. Similarly, there may be issued patents relevant
to  our  product  candidates  of  which  we  or  our  licensors  are  not  aware.  Publications  of  discoveries  in  the  scientific  literature  often  lag  behind  the  actual
discoveries, and patent applications in the U.S. and other jurisdictions are typically not published until 18 months after a first filing, or in some cases not at all.
Therefore, we cannot know with certainty whether we or such licensors were the first to make the inventions claimed in patents or pending patent applications
that we own or licensed, or that we and our licensors were the first to file for patent protection of such inventions. In the event that a third party has also filed a
U.S. patent application relating to our product candidates or a similar invention, depending upon the priority dates claimed by the competing parties, we may
have to participate in interference proceedings declared by the USPTO to determine priority of invention in the U.S. The costs of these proceedings could be
substantial, and it is possible that our efforts to establish priority of invention would be unsuccessful, resulting in a material adverse effect on our U.S. patent
position. As a result, the issuance, scope, validity, enforceability and commercial value of our or any of our licensors’ patent rights are highly uncertain.

There is a substantial amount of litigation involving patent and other intellectual property rights in the biotechnology and biopharmaceutical industries generally.
If a third party claims that we or any of our licensors, suppliers or collaborators infringe the third party’s intellectual property rights, we may have to, among
other things:

●

●

●

obtain additional licenses, which may not be available on commercially reasonable terms, if at all;

abandon  an  infringing  product  candidate  or  redesign  products  or  processes  to  avoid  infringement,  which  may  demand  substantial  funds,  time  and
resources and which may result in inferior or less desirable processes and/or products;

pay substantial damages, including the possibility of treble damages and attorneys’ fees, if a court decides that the product or proprietary technology at
issue infringes on or violates the third party’s rights;

●

pay substantial royalties, fees and/or grant cross-licenses to our product candidates; and/or

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●

defend litigation or administrative proceedings which may be costly regardless of outcome, and which could result in a substantial diversion of financial
and management resources.

Intellectual property litigation could cause us to spend substantial resources and distract our personnel from their normal responsibilities.

Even if resolved in our favor, litigation or other legal proceedings relating to intellectual property claims may cause us to incur significant expenses and could
distract our technical and management personnel from their normal responsibilities. In addition, there could be public announcements of the results of hearings,
motions or other interim proceedings or developments and if securities analysts or investors perceive these results to be negative, it could have a substantial
adverse  effect  on  the  price  of  our  common  stock.  Such  litigation  or  proceedings  could  substantially  increase  our  operating  losses  and  reduce  the  resources
available for development activities or any future sales, marketing or distribution activities. We may not have sufficient financial or other resources to conduct
such litigation or proceedings adequately. Some of our competitors may be able to sustain the costs of such litigation or proceedings more effectively than we
can  because  of  their  greater  financial  resources.  Uncertainties  resulting  from  the  initiation  and  continuation  of  patent  litigation  or  other  proceedings  could
compromise our ability to compete in the marketplace.

If  we  fail  to  comply  with  our  obligations  under  our  intellectual  property  licenses  and  third  party  funding  arrangements,  we  could  lose  rights  that  are
important to our business.

We are currently a party to license agreements with St. Jude, COH, Fred Hutch, UCLA, Nationwide and other institutions. In the future, we may become party to
licenses that are important for product development and commercialization. If we fail to comply with our obligations under current or future license and funding
agreements, our counterparties may have the right to terminate these agreements, in which event we might not be able to develop, manufacture or market any
product or utilize any technology that is covered by these agreements or may face other penalties under the agreements. Such an occurrence could materially and
adversely affect the value of a product candidate being developed under any such agreement or could restrict our drug discovery activities. Termination of these
agreements  or  reduction  or  elimination  of  our  rights  under  these  agreements  may  result  in  our  having  to  negotiate  new  or  reinstated  agreements  with  less
favorable terms, or cause us to lose our rights under these agreements, including our rights to important intellectual property or technology.

We may be subject to claims that our employees and/or consultants have wrongfully used or disclosed to us alleged trade secrets of their former employers
or other clients.

As is common in the biopharmaceutical industry, we rely on employees and consultants to assist in the development of product candidates, many of whom were
previously  employed  at,  or  may  have  previously  been  or  are  currently  providing  consulting  services  to,  other  biopharmaceutical  companies,  including  our
competitors or potential competitors. We may become subject to claims related to whether these individuals have inadvertently or otherwise used, disclosed or
misappropriated trade secrets or other proprietary information of their former employers or their former or current clients. Litigation may be necessary to defend
against these claims. Even if we are successful in defending these claims, litigation could result in substantial costs and be a distraction to management and/or the
employees or consultants that are implicated.

If we are unable to protect the confidentiality of our trade secrets, our business and competitive position would be harmed.

In addition to seeking patent protection for our product candidates or any future product candidate, we also rely on trade secrets, including unpatented know-
how, technology and other proprietary information, to maintain our competitive position, particularly where we do not believe patent protection is appropriate or
obtainable. However, trade secrets are difficult to protect. We limit disclosure of such trade secrets where possible but we also seek to protect these trade secrets,
in part, by entering into non-disclosure and confidentiality agreements with parties who do have access to them, such as our employees, our licensors, corporate
collaborators,  outside  scientific  collaborators,  contract  manufacturers,  consultants,  advisors  and  other  third  parties.  We  also  enter  into  confidentiality  and
invention or patent assignment agreements with our employees and consultants. Despite these efforts, any of these parties may breach the agreements and may
unintentionally  or  willfully  disclose  our  proprietary  information,  including  our  trade  secrets,  and  we  may  not  be  able  to  obtain  adequate  remedies  for  such
breaches.  Enforcing  a  claim  that  a  party  illegally  disclosed  or  misappropriated  a  trade  secret  is  difficult,  expensive  and  time-consuming,  and  the  outcome  is
unpredictable. In addition, some courts inside and outside the United States are less willing or unwilling to protect trade secrets. Moreover, if any of our trade
secrets were to be lawfully obtained or independently developed by a competitor, we would have no right to prevent them, or those to whom they communicate
it, from using that technology or information to compete with us. If any of our trade secrets were to be disclosed to or independently developed by a competitor,
our competitive position would be harmed.

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We  in-license  intellectual  property  pertaining  to  certain  product  candidates  from  third  parties.  As  such,  any  dispute  with  the  licensors  or  the  non-
performance of such license agreements may adversely affect our ability to develop and commercialize the applicable product candidates.

The types of disputes which may arise between us and the third parties from whom we license intellectual property include, but are not limited to:

●

●

●

●

●

the scope of rights granted under such license agreements and other interpretation-related issues;

the extent to which our technology and processes infringe on intellectual property of the licensor that is not subject to such license agreements;

the scope and interpretation of the representations and warranties made to us by our licensors, including those pertaining to the licensors’ right title and
interest in the licensed technology and the licensors’ right to grant the licenses contemplated by such agreements;

the sublicensing of patent and other rights under our license agreements and/or collaborative development relationships, and the rights and obligations
associated with such sublicensing, including whether or not a given transaction constitutes a sublicense under such license agreement;

the  diligence  and  development  obligations  under  license  agreements  (which  may  include  specific  diligence  milestones)  and  what  activities  or
achievements satisfy those diligence obligations;

● whether or not the milestones associated with certain milestone payment obligations have been achieved or satisfied;

●

●

●

●

the applicability or scope of indemnification claims or obligations under such license agreements;

the permissibility and advisability of, and strategy regarding, the pursuit of potential third-party infringers of the intellectual property that is the subject of
such license agreements;

the calculation of royalty, sublicense revenue and other payment obligations under such license agreements;

the extent to which license rights, if any, are retained by licensors under such license agreements;

● whether or not a material breach has occurred under such license agreements and the extent to which such breach, if deemed to have occurred, is or can

be cured within applicable cure periods, if any;

●

●

disputes regarding patent filing and prosecution decisions, as well as payment obligations regarding past and ongoing patent expenses;

intellectual  property  rights  resulting  from  the  joint  creation  or  use  of  intellectual  property  (including  improvements  made  to  licensed  intellectual
property) by our and our partners’ licensors and us and our partners; and

●

the priority of invention of patented technology.

In addition, the agreements under which we currently license intellectual property or technology from third parties are complex, and certain provisions in such
agreements may be susceptible to multiple interpretations or may conflict in such a way that puts us in breach of one or more agreements, which would make us
susceptible to lengthy and expensive disputes with one or more of such third-party licensing partners. The resolution of any contract interpretation disagreement
that may arise could narrow what we believe to be the scope of our rights to the relevant intellectual property or technology, or increase what we believe to be
our financial or other obligations under the relevant agreements, either of which could have a material adverse effect on our business, financial condition, results
of operations and prospects. Moreover, if disputes over intellectual property that we have licensed prevent or impair our ability to maintain our current licensing
arrangements on commercially acceptable terms, we may be unable to successfully develop and commercialize the affected product candidates, which could
have a material adverse effect on our business, financial conditions, results of operations and prospects.

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Fortress controls a voting majority of our common stock.

Risks Relating to Our Control by Fortress Biotech Inc.

Pursuant to the terms of the Class A Preferred Stock held by Fortress, Fortress is entitled to cast, for each share of Class A Preferred held by Fortress, the number
of votes that is equal to one and one-tenth (1.1) times a fraction, the numerator of which is the sum of (A) the shares of outstanding common stock and (B) the
whole  shares  of  common  stock  into  which  the  shares  of  outstanding  Class  A  common  shares  and  the  Class  A  Preferred  Stock  are  convertible  and  the
denominator  of  which  is  the  number  of  shares  of  outstanding  Class A  Preferred  Stock. Accordingly,  Fortress  is  able  to  control  or  significantly  influence  all
matters requiring approval by our stockholders, including the election of directors and the approval of mergers or other business combination transactions. The
interests  of  Fortress  may  not  always  coincide  with  the  interests  of  other  stockholders,  and  Fortress  may  take  actions  that  advance  its  own  interests  and  are
contrary to the desires of our other stockholders. Moreover, this concentration of voting power may delay, prevent or deter a change in control of us even when
such a change may be in the best interests of all stockholders, could deprive our stockholders of an opportunity to receive a premium for their common stock as
part of a sale of Mustang or our assets, and might affect the prevailing market price of our common stock.

Fortress has the right to receive a significant grant of shares of our common stock annually which will result in the dilution of your holdings of common
stock upon each grant, which could reduce their value.

Under the terms of the Second Amended and Restated Founders Agreement, which became effective July 22, 2016, Fortress will receive a grant of shares of our
common stock equal to two and one-half percent (2.5%) of the gross amount of any equity or debt financing. Additionally, the Class A Preferred Stock, as a
class, will receive an annual dividend on January 1st, payable in shares of common stock in an amount equal to two and one-half percent (2.5%) of our fully-
diluted outstanding capital stock as of the business day immediately prior to January 1st of such year. Fortress currently owns all outstanding shares of Class A
Preferred Stock. These share issuances to Fortress and any other holder of Class A Preferred Stock will dilute your holdings in our common stock and, if the
value of Mustang has not grown proportionately over the prior year, would result in a reduction in the value of your shares. The Second Amended and Restated
Founders Agreement  has  a  term  of  15  years  and  renews  automatically  for  subsequent  one-year  periods  unless  terminated  by  Fortress  or  upon  a  Change  in
Control (as defined in the Second Amended and Restated Founders Agreement).

We might have received better terms from unaffiliated third parties than the terms we receive in our agreements with Fortress.

The agreements we have entered into with Fortress include a Management Services Agreement and the Founders Agreement. While we believe the terms of
these agreements are reasonable, they might not reflect terms that would have resulted from arm’s-length negotiations between unaffiliated third parties. The
terms of the agreements relate to, among other things, payment of a royalty on product sales and the provision of employment and transition services. We might
have received better terms from third parties because, among other things, third parties might have competed with each other to win our business.

The dual roles of our directors who also serve in similar roles with Fortress could create a conflict of interest and will require careful monitoring by our
independent directors.

We share some directors with Fortress which could create conflicts of interest between the two companies in the future. While we believe that the Founders
Agreement and the Management Services Agreement were negotiated by independent parties on both sides on arm’s length terms, and the fiduciary duties of
both parties were thereby satisfied, in the future situations may arise under the operation of both agreements that may create a conflict of interest. We will have
to be diligent to ensure that any such situation is resolved by independent parties. In particular, under the Management Services Agreement, Fortress and its
affiliates are free to pursue opportunities which could potentially be of interest to Mustang, and they are not required to notify Mustang prior to pursuing such
opportunities. Any such conflict of interest or pursuit by Fortress of a corporate opportunity independent of Mustang could expose us to claims by our investors
and creditors and could harm our results of operations.

General Risks

Major public health issues, and specifically the pandemic caused by the spread of COVID-19, could have an adverse impact on our financial condition and
results of operations and other aspects of our business.

In December 2019, a novel strain of coronavirus, COVID-19, was first detected in Wuhan, China, and has since spread around the world. On March 11, 2020,
the  World  Health  Organization  declared  that  the  rapidly  spreading COVID-19 outbreak  had  evolved  into  a  pandemic.  In  response  to  the  pandemic,  many
governments around the world are implementing a variety of measures to reduce the spread of COVID-

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19,  including  travel  restrictions  and  bans,  instructions  to  residents  to  practice  social  distancing,  quarantine  advisories,  shelter-in-place  orders  and  required
closures of non-essential businesses.

The  COVID-19  pandemic  has  negatively  impacted  the  global  economy,  disrupted  global  supply  chains,  and  created  significant  volatility  and  disruption  of
financial markets. Although COVID-19 has not had a material adverse effect on our business to date, no assurance can be given that it will not in the future if the
situation persists or worsens. The extent to which the coronavirus impacts our business and operating results will depend on future developments that are highly
uncertain and cannot be accurately predicted, including new information that may emerge concerning the coronavirus and the actions to contain the coronavirus
or treat its impact, among others.

Should  the  coronavirus  continue  to  spread,  our  business  operations  could  be  delayed  or  interrupted.  For  instance,  our  clinical  trials  may  be  affected  by  the
pandemic. Site initiation, participant recruitment and enrollment, participant dosing, distribution of clinical trial materials, study monitoring and data analysis
may  be  paused  or  delayed  due  to  changes  in  hospital  or  university  policies,  federal,  state  or  local  regulations,  prioritization  of  hospital  resources  toward
pandemic efforts, or other reasons related to the pandemic. If the coronavirus continues to spread, some participants and clinical investigators may not be able to
comply  with  clinical  trial  protocols.  For  example,  quarantines  or  other  travel  limitations  (whether  voluntary  or  required)  may  impede  participant  movement,
affect sponsor access to study sites, or interrupt healthcare services, and we may be unable to conduct our clinical trials. Infections and deaths related to the
pandemic may disrupt the United States’ and other countries’ healthcare and healthcare regulatory systems. Such disruptions could divert healthcare resources
away from, or materially delay FDA or other regulatory review and/or approval with respect to, our clinical trials. It is unknown how long these disruptions
could continue, were they to occur. Any elongation or de-prioritization of our clinical trials or delay in regulatory review resulting from such disruptions could
materially affect the development and study of our product candidates.

We currently rely on third parties, such as contract laboratories, contract research organizations, medical institutions and clinical investigators to conduct these
studies  and  clinical  trials.  If  these  third  parties  themselves  are  adversely  impacted  by  restrictions  resulting  from  the  coronavirus  outbreak,  we  will  likely
experience delays and/or realize additional costs. We also rely on third parties for the manufacture of our product candidates for preclinical and clinical testing.
Disruptions  to  the  global  supply  chain  could  impact  our  or  our  third-party  manufacturers’  ability  to  obtain  raw  materials  or  other  products  necessary  to
manufacture and distribute our product candidates. As a result, our efforts to obtain regulatory approvals for, and to commercialize, our product candidates may
be delayed or disrupted.

The potential economic impact brought by and the duration of the pandemic may be difficult to assess or predict, however it has already caused, and is likely to
result in further, significant disruption of global financial markets, which may reduce our ability to access capital either at all or on favorable terms. In addition,
a recession, depression or other sustained adverse market event resulting from the spread of the coronavirus could materially and adversely affect our business
and the value of our common stock.

The ultimate impact of the current pandemic, or any other health epidemic, is highly uncertain and will depend on future developments that cannot be predicted
with confidence, such as the duration of the outbreak, the severity of COVID-19, and the effectiveness of actions to contain and treat for COVID-19. Although,
as  of  the  date  of  this Annual  Report  on  Form  10-K,  we  do  not  expect  any  material  impact  on  our  long-term  activity,  we  do  not  yet  know  the  full  extent  of
potential delays or impacts on our business, our clinical trials, our research programs, healthcare systems or the global economy as a whole, which could have a
material adverse effect on our business, financial condition and results of operations and cash flows.

The ability of the Company’s employees and consultants to work may be significantly impacted by the coronavirus.

The  Company’s  employees  and  consultants  are  being  affected  by  the  COVID-19  pandemic.  Substantially  all  of  our  office  and  management  personnel  are
working  remotely,  and  the  Company  may  need  to  enact  further  precautionary  measures  to  help  minimize  the  risk  of  our  employees  being  exposed  to  the
coronavirus. COVID-19 may also compromise the ability of independent contractors who perform consulting services for us to deliver services or deliverables in
a satisfactory or timely manner.  Further, our management team is focused on mitigating the adverse effects of the COVID-19 pandemic, which has required and
will continue to require a large investment of time and resources, thereby diverting their attention from other priorities that existed prior to the outbreak of the
pandemic. If these conditions worsen, or last for an extended period of time, the Company’s ability to manage its business may be impaired, and operational
risks, cybersecurity risks and other risks facing the Company even prior to the pandemic may be elevated.

We may not be able to manage our business effectively if we are unable to attract and retain key personnel.

We may not be able to attract or retain qualified management and commercial, scientific and clinical personnel in the future due to the intense competition for
qualified personnel among biotechnology, pharmaceutical and other businesses. If we are not able to attract and

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retain  necessary  personnel  to  accomplish  our  business  objectives,  we  may  experience  constraints  that  will  significantly  impede  the  achievement  of  our
development objectives, our ability to raise additional capital and our ability to implement our business strategy.

Our  employees,  consultants,  or  third-party  partners  may  engage  in  misconduct  or  other  improper  activities,  including  but  not  necessarily  limited  to
noncompliance  with  regulatory  standards  and  requirements  or  internal  procedures,  policies  or  agreements  to  which  such  employees,  consultants  and
partners are subject, any of which could have a material adverse effect on our business.

We  are  exposed  to  the  risk  of  employee  fraud  or  other  misconduct.  Misconduct  by  employees,  consultants,  or  third-party  partners  could  include  intentional
failures to comply with FDA regulations, provide accurate information to the FDA, comply with cGMPs, comply with federal and state healthcare fraud and
abuse laws and regulations, report financial information or data accurately, comply with internal procedures, policies or agreements to which such employees,
consultants or partners are subject, or disclose unauthorized activities to us. In particular, sales, marketing and business arrangements in the healthcare industry
are  subject  to  extensive  laws  and  regulations  intended  to  prevent  fraud,  kickbacks,  self-dealing  and  other  abusive  practices.  These  laws  and  regulations  may
restrict  or  prohibit  a  wide  range  of  pricing,  discounting,  marketing  and  promotion,  sales  commission,  customer  incentive  programs  and  other  business
arrangements. Employee, consultant, or third-party misconduct could also involve the improper use of information obtained in the course of clinical trials, which
could result in regulatory sanctions and serious harm to our reputation, as well as civil and criminal liability. The precautions we take to detect and prevent this
activity  may  not  be  effective  in  controlling  unknown  or  unmanaged  risks  or  losses  or  in  protecting  us  from  governmental  investigations  or  other  actions  or
lawsuits stemming from a failure to be in compliance with such laws or regulations. If any such actions are instituted against us, and we are not successful in
defending ourselves or asserting our rights, those actions could have a significant impact on our business and results of operations, including the imposition of
significant fines or other civil and/or criminal sanctions.

We receive a large amount of proprietary information from potential or existing licensors of intellectual property and potential acquisition target companies, all
pursuant to confidentiality agreements. The confidentiality and proprietary invention assignment agreements that we have in place with each of our employees
and consultants prohibit the unauthorized disclosure of such information, but such employees or consultants may nonetheless disclose such information through
negligence  or  willful  misconduct. Any  such  unauthorized  disclosures  could  subject  us  to  monetary  damages  and/or  injunctive  or  equitable  relief.  The  notes,
analyses  and  memoranda  that  we  have  generated  based  on  such  information  are  also  valuable  to  our  businesses,  and  the  unauthorized  disclosure  or
misappropriation of such materials by our employees and consultants could significantly harm our strategic initiatives – especially if such disclosures are made
to our competitors.

We rely on information technology, and any internet or internal computer system failures, inadequacies, interruptions or compromises of our systems or the
security of confidential information could damage our reputation and harm our business.

Although a significant portion of our business is conducted using traditional methods of contact and communications such as face-to-face meetings, our business
is  increasingly  dependent  on  critical,  complex  and  interdependent  information  technology  systems,  including  internet-based  systems,  to  support  business
processes as well as internal and external communications. We could experience system failures and degradations in the future. We cannot assure you that we
will be able to prevent an extended and/or material system failure if any of the following or similar events occurs:

●

●

●

●

●

human error;

subsystem, component, or software failure;

a power or telecommunications failure;

hacker attacks, cyber-attacks, software viruses, security breaches, unauthorized access or intentional acts of vandalism; or

terrorist acts or war.

If any of the foregoing events were to occur, our business operations could be disrupted in ways that would require the incurrence of substantial expenditures to
remedy. Any system failure, accident or security breach that causes interruptions in our operations could result in a material disruption of our drug development
programs.  For  example,  the  loss  of  clinical  trial  data  from  completed  clinical  trials  for  one  or  more  of  our  product  conducts  could  result  in  delays  in  our
regulatory approval efforts and significantly increase our costs to recover or reproduce the data. To the extent that any disruption or security breach were to result
in a loss of, or damage to, our data and applications, or inappropriate/unauthorized disclosure of confidential or proprietary information (including trade secrets),
we could incur liability and our business and financial condition could be harmed.

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The occurrence of a catastrophic disaster could damage our facilities beyond insurance limits, or we could lose key data which could cause us to curtail or
cease operations.

We are vulnerable to damage and/or loss of vital data from natural disasters, such as earthquakes, tornadoes, power loss, fire, health epidemics and pandemics,
floods and similar events, as well as from accidental loss or destruction. If any disaster were to occur, our ability to operate our businesses could be seriously
impaired.  We  have  property,  liability  and  business  interruption  insurance  that  may  not  be  adequate  to  cover  losses  resulting  from  disasters  or  other  similar
significant  business  interruptions,  and  we  do  not  plan  to  purchase  additional  insurance  to  cover  such  losses  due  to  the  cost  of  obtaining  such  coverage. Any
significant  losses  that  are  not  recoverable  under  our  insurance  policies  could  seriously  impair  our  business,  financial  condition  and  prospects. Any  of  the
aforementioned  circumstances,  including  without  limitation  the  emerging  COVID-19  virus,  may  also  impede  our  employees’  and  consultants’  abilities  to
provide  services  in-person  and/or  in  a  timely  manner;  hinder  our  ability  to  raise  funds  to  finance  our  operations  on  favorable  terms  or  at  all;  and  trigger
effectiveness of “force majeure” clauses under agreements with respect to which we receive goods and services, or under which we are obligated to achieve
developmental  milestones  on  certain  timeframes.  Disputes  with  third  parties  over  the  applicability  of  such  “force  majeure”  clauses,  or  the  enforceability  of
developmental milestones and related extension mechanisms in light of such business interruptions, may arise and may become expensive and time-consuming.

Our stock may be subject to substantial price and volume fluctuations due to a number of factors, many of which are beyond our control and may prevent
our stockholders from reselling our common stock at a profit.

The market prices for securities of biotechnology and pharmaceutical companies have historically been highly volatile, and the market has from time to time
experienced significant price and volume fluctuations that are unrelated to the operating performance of particular companies.

The market price of our common stock is likely to be highly volatile and may fluctuate substantially due to many factors, including:

●

announcements concerning the progress of our efforts to obtain regulatory approval for and commercialize our product candidates or any future product
candidate,  including  any  requests  we  receive  from  the  FDA  for  additional  studies  or  data  that  result  in  delays  in  obtaining  regulatory  approval  or
launching these product candidates, if approved;

● market conditions in the pharmaceutical and biotechnology sectors or the economy as a whole;

●

●

●

●

●

●

●

●

●

●

●

price and volume fluctuations in the overall stock market;

the failure of one or more of our product candidates or any future product candidate, if approved, to achieve commercial success;

announcements of the introduction of new products by us or our competitors;

developments concerning product development results or intellectual property rights of others;

litigation or public concern about the safety of our potential products;

actual fluctuations in our quarterly operating results, and concerns by investors that such fluctuations may occur in the future;

deviations in our operating results from the estimates of securities analysts or other analyst comments;

additions or departures of key personnel;

health  care  reform  legislation,  including  measures  directed  at  controlling  the  pricing  of  pharmaceutical  products,  and  third-party  coverage  and
reimbursement policies;

developments concerning current or future strategic collaborations; and

discussion of us or our stock price by the financial and scientific press and in online investor communities.

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We may become involved in securities class action litigation that could divert management’s attention and harm our business.

The stock markets have from time to time experienced significant price and volume fluctuations that have affected the market prices for the common stock of
biotechnology and pharmaceutical companies. These broad market fluctuations may cause the market price of our stock to decline. In the past, securities class
action litigation has often been brought against a company following a decline in the market price of its securities. This risk is especially relevant for us because
biotechnology and biopharmaceutical companies have experienced significant stock price volatility in recent years. We may become involved in this type of
litigation in the future. Litigation often is expensive and diverts management’s attention and resources, which could adversely affect our business.

Item 1B.       Unresolved Staff Comments

None.

Item 2.        Properties

Our corporate and executive office is located at 377 Plantation Street, Worcester, MA 01605.

On October 27, 2017, we entered into a lease agreement with WCS - 377 Plantation Street, Inc., a Massachusetts nonprofit corporation (“Landlord”). Pursuant to
the terms of the lease agreement, we agreed to lease 27,043 sf from the Landlord, located at 377 Plantation Street in Worcester, MA (the “Facility”), through
November  2026,  subject  to  additional  extensions  at  our  option.  Base  rent,  net  of  abatements  of  $0.6  million  over  the  lease  term,  totals  approximately  $3.6
million, on a triple-net basis.

The Facility became operational for the production of personalized CAR T and gene therapies in 2018.

Item 3.      Legal Proceedings

We are not involved in any litigation that we believe could have a material adverse effect on our financial position or results of operations. There is no action,
suit,  proceeding,  inquiry  or  investigation  before  or  by  any  court,  public  board,  government  agency,  self-regulatory  organization  or  body  pending  or,  to  the
knowledge of our executive officers, threatened against or affecting our company or our officers or directors in their capacities as such.

Item 4.        Mine Safety Disclosures

Not applicable

Item 5.      Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities

Market information

PART II

Our common stock has been quoted on the NASDAQ Global Market since August 22, 2017, under the symbol “MBIO.” Prior to this there was no public market
for our common stock.

Securities Authorized for Issuance Under Equity Compensation Plans

On November 30, 2017, we filed a registration statement on Form S-8 under the Securities Act registering the common stock issued, issuable or reserved for
issuance under our 2016 Plan. That registration statement became effective immediately upon filing, and shares covered by the registration statement are eligible
for sale in the public markets, subject to grant of the underlying awards, vesting provisions and Rule 144 limitations applicable to our affiliates.

Holders of Record

As of December 31, 2020,  there were approximately 113 holders of record of our common stock and one holder of record for our Class A common stock. The
actual number of stockholders of our common shares is greater than this number of record holders and includes

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stockholders who are beneficial owners, but whose shares are held in street name by brokers and other nominees. This number of holders of record also does not
include stockholders whose shares may be held in trust by other entities.

Dividends

We have never paid or declared any cash dividends on our common stock, and we do not anticipate paying any cash dividends on our common stock in the
foreseeable  future.  We  intend  to  retain  all  available  funds  and  any  future  earnings  to  fund  the  development  and  expansion  of  our  business.  Any  future
determination to pay dividends will be at the discretion of our board of directors and will depend upon a number of factors, including our results of operations,
financial condition, future prospects, contractual restrictions, restrictions imposed by applicable law and other factors our board of directors deems relevant.

Recent Sales of Unregistered Securities

None.

Item 6.       Reserved

Item 7.       Management’s Discussion and Analysis of the Results of Operations

Statements in the following discussion and throughout this report that are not historical in nature are “forward-looking statements.” You can identify forward-
looking  statements  by  the  use  of  words  such  as  “expect,”  “anticipate,”  “estimate,”  “may,”  “will,”  “should,”  “intend,”  “believe,”  and  similar  expressions.
Although we believe the expectations reflected in these forward-looking statements are reasonable, such statements are inherently subject to risk and we can
give no assurances that our expectations will prove to be correct. Actual results could differ from those described in this report because of numerous factors,
many of which are beyond our control. These factors include, without limitation, those described under Item 1A “Risk Factors.” We undertake no obligation to
update  these  forward-looking  statements  to  reflect  events  or  circumstances  after  the  date  of  this  report  or  to  reflect  actual  outcomes.  Please  see  “Forward-
Looking Statements” at the beginning of this Form 10-K.

The following discussion of our financial condition and results of operations should be read in conjunction with our financial statements and the related notes
thereto and other financial information appearing elsewhere in this Form 10-K. We undertake no obligation to update any forward-looking statements in the
discussion of our financial condition and results of operations to reflect events or circumstances after the date of this report or to reflect actual outcomes.

Overview

Mustang  Bio,  Inc.  (“Mustang,”  “We,”  “Us”  or  the  “Company”)  is  a  clinical-stage  biopharmaceutical  company  focused  on  translating  today’s  medical
breakthroughs in cell and gene therapies into potential cures for hematologic cancers, solid tumors and rare genetic diseases. We aim to acquire rights to these
technologies by licensing or otherwise acquiring an ownership interest in the technologies, funding their research and development and eventually either out-
licensing or bringing the technologies to market.

Our pipeline is currently focused in three core areas: gene therapy programs for rare genetic disorders, chimeric antigen receptor (“CAR”) engineered T cell
(“CAR  T”)  therapies  for  hematologic  malignancies  and  CAR  T  therapies  for  solid  tumors.  For  each  therapy  we  have  partnered  with  world  class  research
institutions. For our gene therapy program, we have partnered with St. Jude Children’s Research Hospital (“St. Jude”) in the development of a first-in-class ex
vivo  lentiviral  treatment  of  X-linked  severe  combined  immunodeficiency  (“XSCID”)  and  for  our  CAR  T  therapies  we  have  partnered  with  the  City  of  Hope
National Medical Center (“COH”), Fred Hutchinson Cancer Research Center (“Fred Hutch”) and Nationwide Children’s Hospital (“Nationwide”).

Gene Therapy

In partnership with St. Jude and the National Institutes of Health (“NIH”), our gene therapy program is being conducted under an exclusive license to develop a
potentially  curative  treatment  for  XSCID,  a  rare  genetic  immune  system  condition  also  known  as  bubble  boy  disease  in  which  affected  patients  do  not  live
beyond  infancy  without  treatment.  This  first-in-class ex  vivo  lentiviral  gene  therapy  is  currently  in  two  Phase  1/2  clinical  trials  involving  two  different
autologous cell products: a multicenter trial of the MB-107 product in newly diagnosed infants sponsored by St. Jude and a single-center trial of the MB-207
product in previously transplanted patients sponsored by the NIH.

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In May 2020, we submitted an Investigational New Drug (“IND”) application with the FDA to initiate a registrational multicenter Phase 2 clinical trial of MB-
107 in newly diagnosed infants with XSCID who are under the age of two. In response, the FDA identified Chemistry, Manufacturing, and Control (“CMC”)
hold issues that Mustang satisfactorily addressed in a December 2020 submission to the FDA, and the CMC hold was removed in January 2021. The trial is
expected to enroll 10 patients who, together with 15 patients enrolled in the current multicenter trial led by St. Jude, will be compared with 25 matched historical
control  patients  who  have  undergone  hematopoietic  stem  cell  transplant  (“HSCT”).  The  primary  efficacy  endpoint  will  be  event-free  survival  and  we  are
targeting topline data from the trial in the second half of 2022.

We  further  expect  to  file  an  IND  in  the  second  quarter  of  2021  for  a  registrational  multicenter  Phase  2  clinical  trial  of  lentiviral  gene  therapy  in  previously
transplanted XSCID patients (MB-207). We anticipate enrolling 20 patients, and we are targeting topline data for this trial in the first half of 2023.

CAR T Therapies

Our  pipeline  of  CAR  T  therapies  is  being  developed  under  exclusive  licenses  from  several  world  class  research  institutions.  Our  strategy  is  to  license  these
technologies, support preclinical and clinical research activities by our partners and transfer the underlying technology to our cell processing facility located in
Worcester, Massachusetts, to conduct our own clinical trials.

We are developing CAR T therapies for hematologic malignancies in partnership with COH targeting CD123 (MB-102) and CS1 (MB-104) and with Fred Hutch
targeting CD20 (MB-106). Phase 1 clinical trials sponsored by COH for MB-102 and MB-104 and by Fred Hutch for MB-106 are underway. In the third quarter
of 2019 the FDA approved our IND application to initiate a multi-center Phase 1/2 clinical trial of MB-102, and our clinical trial began enrollment in 2020 for
the treatment of patients with blastic plasmacytoid dendritic cell neoplasm. We expect to file an IND for MB-106 in the first quarter of 2021 and to initiate our
own Phase 1/2 clinical trial shortly thereafter for the treatment of patients with non-Hodgkin lymphoma and chronic lymphocytic leukemia. We plan to file an
IND for a multicenter Phase 1/2 trial for MB-104 for the treatment of patients with multiple myeloma once COH has established a safe and effective dose.

We are also developing CAR T therapies for solid tumors in partnership with COH targeting  IL13Rα2  (MB-101),  HER2  (MB-103)  and  PSCA  (MB-105).  In
addition, we have partnered with Nationwide for the C134 oncolytic virus (MB-108) in order to enhance the activity of MB-101 for the treatment of patients with
glioblastoma  multiforme  (“GBM”).  Phase  1  clinical  trials  sponsored  by  COH  for  MB-101,  MB-103  and  MB-105  are  underway.  A  Phase  1  clinical  trial
sponsored by the University of Alabama at Birmingham (“UAB”) for MB-108 began during the third quarter of 2019 and, in the fourth quarter of 2021, we plan
to file an IND for the combination of MB-101 and MB-108 for the treatment of patients with GBM. We also plan to file INDs and initiate our own clinical trials
for MB-103 for the treatment of patients with metastatic breast cancer to brain and for MB-105 for the treatment of patients with prostate and pancreatic cancer.

Recent Events

MB-106 (CD20 CAR T for Non-Hodgkin Lymphoma and Chronic Lymphocytic Leukemia)

In  February  2020,  we  announced  that  the  first  subject  treated  with  the  optimized  MB-106  (CD20-targeted,  autologous  CAR  T  cell  therapy)  manufacturing
process, developed in collaboration with Fred Hutch, achieved a complete response at the lowest starting dose in an ongoing Phase 1/2 clinical trial. The trial is
evaluating the safety and efficacy of MB-106 in subjects with relapsed or refractory B-cell non-Hodgkin lymphomas and chronic lymphocytic leukemia.

In December 2020, at the 62nd American Society of Hematology Annual Meeting, Mustang and Fred Hutch announced interim data in patients with relapsed or
refractory B-cell NHL from the ongoing Phase 1/2 clinical trial of MB-106 at Fred Hutch. Data presented by Fred Hutch reported on an initial seven patients
treated  without  response  and  without  significant  CAR  T  cell  expansion  or  persistence. Among  these  7  patients  there  was  one  occurrence  of  cytokine  release
syndrome (CRS; grade 3 – unexplained alkaline phosphatase elevation in the setting of fever), and there were no occurrences of immune effector cell-associated
neurotoxicity syndrome (ICANS). Subsequently the trial was put on hold while Fred Hutch collaborated with Mustang to undertake a major modification in the
cell manufacturing process.

Following IND amendment to implement this modified cell processing, 9 patients – 7 with follicular lymphoma and 2 with mantle cell lymphoma – were treated
at 4 different dose levels ranging from 1 x 105 CAR T cells/kg to 3.3 x 106 CAR T cells/kg. The overall response rate was 89% (8/9), the complete response rate
was 44% (4/9), and there was good expansion and persistence of CAR T cells. All complete responses were ongoing at the time of data disclosure. One patient
experienced a grade 1 episode of CRS, and no patients experienced ICANS. Mustang plans to file an IND at the end of the first quarter of 2021 to enable the
initiation of a multicenter Phase 1/2 trial of MB-106.

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MB-107 and MB-207 (Ex vivo Lentiviral Therapy for X-linked Severe Combined Immunodeficiency (XSCID))

In May 2020, we submitted an IND application with the FDA to initiate a registrational multi-center Phase 2 clinical trial of MB-107 in newly diagnosed infants
with XSCID who are under the age of two. In response, the FDA identified CMC hold issues that we satisfactorily addressed in a December 2020 submission to
the FDA, and the CMC hold was removed in January 2021. The trial is expected to enroll 10 patients who, together with 15 patients enrolled in the current
multicenter trial led by St. Jude, will be compared with 25 matched historical control patients who have undergone hematopoietic stem cell transplant (“HSCT”).
The primary efficacy endpoint will be event-free survival and potential topline data from the trial are expected in the fourth quarter of 2022.

In  August  2020,  we  announced  that  the  FDA  has  granted  Rare  Pediatric  Disease  Designation  to  MB-107  and  MB-207.  The  FDA  previously  granted
Regenerative Medicine Advanced Therapy designation to MB-107 for the treatment of XSCID in newly-diagnosed infants in August 2019. Additionally, the
European Medicines Agency granted Advanced Therapy Medicinal Product classification to MB-107 in April 2020.

The FDA grants Rare Pediatric Disease Designation for serious and life-threatening diseases that primarily affect children ages 18 years or younger and affect
fewer than 200,000 people in the United States. If Mustang’s BLA is approved, the company may be eligible to receive a priority review voucher, which can be
redeemed to obtain priority review for any subsequent marketing application and may be sold or transferred. This program is intended to encourage development
of new drugs and biologics for the prevention and treatment of rare pediatric diseases.

In September 2020, we announced that the FDA has granted Orphan Drug Designation to MB-107 and MB-207. The FDA grants Orphan Drug Designation to
drugs and biologics that are intended for the safe and effective treatment, diagnosis or prevention of rare diseases or disorders that affect fewer than 200,000
people  in  the  U.S.  Orphan  Drug  Designation  provides  certain  incentives,  such  as  tax  credits  toward  the  cost  of  clinical  trials  and  prescription  drug  user  fee
waivers. If a product holding Orphan Drug Designation receives the first FDA approval for the disease in which it has such designation, the product is entitled to
seven years of market exclusivity, which is independent from intellectual property protection.

In October 2020, we in-licensed LentiBOOST™ technology from SIRION Biotech GmbH for the development of MB-207.

In November 2020, we signed an agreement with Minaris Regenerative Medicine GmbH to enable technology transfer and GMP clinical manufacturing of the
MB-107 lentiviral gene therapy program for the treatment of XSCID in Europe.

Also in November 2020, we announced that the European Commission issued a positive opinion on its application for Orphan Drug Designation for the MB-107
lentiviral gene therapy for the treatment of XSCID.

MB-102 (CD123-targeted CAR T cell therapy)

In  October  2020,  we  announced  that  the  first  patient  has  been  dosed  in  a  Mustang-sponsored,  open  label,  multicenter  Phase  1/2  clinical  trial  to  evaluate  the
safety and efficacy of MB-102 in patients with relapsed or refractory BPDCN. Study sites include City of Hope, where the CAR T cell therapy was initially
developed and where the clinical data were generated to support Mustang’s current multicenter trial, Dana-Farber Cancer Institute, Duke University and MD
Anderson Cancer Center.

The Phase 1 portion of the trial will determine the maximum tolerated dose of MB-102 for the Phase 2 portion of the trial. Safety will be assessed at each dose
level before proceeding to the next. Depending on the efficacy and safety profile of MB-102 in the Phase 1 portion of the trial, relapsed or refractory AML and
demethylation resistant hrMDS may be added to the later dose escalation cohorts. The Phase 2 portion of the trial may be divided into as many as three arms to
evaluate the efficacy of MB-102 in relapsed or refractory BPDCN (Arm 1), relapsed or refractory AML (Arm 2) and demethylation resistant hrMDS (Arm 3).
The primary outcome that will be studied is the response rate at day 28 post infusion in all arms. Secondary outcome measures include duration of response,
progression-free survival, overall survival and incidence of treatment-emergent adverse events, which will be followed for up to three years.

MB-101 (IL13Rα2-targeted CAR T cell therapy)

In December 2020, we announced that a Phase 1 single-center, two-arm clinical trial was initiated to establish the safety and feasibility of administering MB-
101 to patients with leptomeningeal brain tumors (e.g., glioblastoma, ependymoma or medulloblastoma).

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MB-105 (PSCA CAR T for Prostate & Pancreatic Cancers)

In  October  2020,  we  announced  that  one  patient’s  experience  on  the  Phase  1  trial  of  MB-105  was  presented  at  the  virtual  27th  Annual  Prostate  Cancer
Foundation Scientific Retreat. In a 73-year-old male patient with PSCA-positive metastatic castrate-resistant prostate cancer who was treated with MB-105 and
lymphodepletion (a standard CAR T pre-conditioning regimen) after failing eight prior therapies, MB-105 demonstrated on day 28 a 94 percent reduction in
prostate-specific  antigen  (PSA),  near  complete  reduction  of  measurable  soft  tissue  metastasis  by  computerized  tomography,  and  improvement  in  bone
metastases by magnetic resonance imaging. The therapy was associated with cytokine release syndrome, which was clinically managed with tocilizumab (anti-
IL-6 receptor antibody), and hemorrhagic cystitis requiring transfusion which clinically resolved in 30 days.

SIRION Biotech GmbH – LentiBOOSTTM

On  September  30,  2020,  Mustang  entered  into  an  exclusive,  worldwide  licensing  agreement  with  SIRION  Biotech  (“SIRION”)  for  the  rights  to  SIRION’s
LentiBOOSTTM technology for the development of MB-207, Mustang’s lentiviral gene therapy for the treatment of previously transplanted XSCID patients (the
“SIRION Technology License”). Pursuant to the SIRION Technology License, the Company paid a one-time upfront fee of €0.1 million ($0.1 million) during
the  year  ended  December  31,  2020.  In  addition,  five  future  development  milestone  payments  totaling  up  to  approximately  €4.7  million  ($5.5  million)  in  the
aggregate are due upon achievement of certain milestones. Additional milestone payments totaling up to €3.5 million ($4.1 million) in the aggregate are due in
connection with the achievement of three commercial milestones, and low single digit royalties are due on aggregate cumulative worldwide net sales of licensed
products.
Registration Statements

On  October  23,  2020,  the  Company  filed  a  shelf  registration  statement  No.  333-249657  on  Form  S-3  (the  “2020  S-3”),  which  was  declared  effective  on
December  4,  2020.  Under  the  2020  S-3,  the  Company  may  sell  up  to  a  total  of  $100.0  million  of  its  securities. As  of  December  31,  2020,  approximately
$85.7 million of the 2020 S-3 remains available for sales of securities.

Term Loan

On March 29, 2019 (the “Closing Date”), the Company entered into a $20.0 million Loan Agreement with Horizon (the “Loan Agreement”), the proceeds of
which were used to provide the Company with additional working capital to continue development of its gene and cell therapies. In accordance with the Loan
Agreement, $15.0 million of the $20.0 million loan was funded on the Closing Date, with the remaining $5.0 million fundable upon the Company achieving
certain predetermined milestones. On September 30, 2020, the Company repaid in full all amounts that were outstanding under the Loan Agreement.

At-the-Market Offering

On July 13, 2018, the Company filed a shelf registration statement No. 333-226175 on Form S-3, as amended on July 20, 2018 (the “2018 S-3”), which was
declared effective in August 2018. Under the 2018 S-3, the Company may sell up to a total of $75.0 million of its securities. In connection with the 2018 S-3, the
Company entered into an At-the-Market Issuance Sales Agreement (the “ATM Agreement”) with B. Riley Securities, Inc. (formerly B. Riley FBR, Inc.), Cantor
Fitzgerald & Co., National Securities Corporation, and Oppenheimer & Co. Inc. (each an “Agent” and collectively, the “Agents”), relating to the sale of shares
of common stock. Under the ATM Agreement, the Company pays the Agents a commission rate of up to 3.0% of the gross proceeds from the sale of any shares
of common stock. On December 31, 2020, the ATM Agreement was amended to add H.C. Wainwright & Co., LLC as an Agent.

During the year ended December 31, 2020, the Company issued approximately 17.6 million shares of common stock at an average price of $3.40 per share for
gross  proceeds  of  $59.8  million  under  the ATM Agreement.  In  connection  with  these  sales,  we  paid  aggregate  fees  of  approximately  $1.1  million  for  net
proceeds of approximately $58.7 million.

Public Offering of Common Stock

On June 11, 2020, we announced the pricing of an underwritten public offering, whereby we sold 10,769,231 shares of common stock, (plus a 30-day option to
purchase up to an additional 1,615,384 shares of common stock, which was partially exercised) at a price of $3.25 per share for gross proceeds of approximately
$37.2  million,  before  deducting  underwriting  discounts  and  commissions  and  offering  expenses.  In  connection  with  the  public  offering,  the  Company  paid
aggregate fees of approximately $2.4 million for net proceeds of approximately $34.8 million.

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Authorized Shares

On November 11, 2020, the Company’s Board adopted resolutions of the Board to ratify, approve and recommend stockholder approval of an amendment to the
Company’s Amended  and  Restated  Certificate  of  Incorporation,  as  amended,  to  revise Article  IV,  Section A  thereof  in  order  to  effect  an  increase  in  the
authorized number of shares of the Company’s common stock, par value $0.0001, from 85 million to 125 million (the “Amendment”). On November 11, 2020,
the Company received approval of the Amendment by written consent in lieu of a meeting from the holders of a majority of issued and outstanding shares of the
Company’s common and preferred stock. The increase in authorized shares to 125 million became effective on December 4, 2020.

To  date,  we  have  not  received  approval  for  the  sale  of  our  product  candidates  in  any  market  and,  therefore,  have  not  generated  any  product  sales  from  our
product candidates. In addition, we have incurred substantial operating losses since our inception, and expect to continue to incur significant operating losses for
the foreseeable future and may never become profitable. As of December 31, 2020, we have an accumulated deficit of $185.5 million.

We  are  a  majority-controlled  subsidiary  of  Fortress  Biotech,  Inc.  (“Fortress”). As  a  “Controlled  Company”  we  rely  on  the  exemption  provided  by  Nasdaq
Listing Rule 5615(c)(2), which permits us to maintain less than a majority of independent directors on our board.

Critical Accounting Policies and Use of Estimates

See Note 2 to our Financial Statements.

Results of Operations

Comparison of the Years Ended December 31, 2020 and 2019

($in thousands)
Operating expenses:

Research and development
Research and development – licenses acquired
General and administrative

Total operating expenses
Loss from operations

Other income (expense)

Interest income
Interest expense

Total other income (expense)
Net Loss

Research and Development Expenses

For the year ended December 31, 

2020

2019

Change

$

%

$

$

 37,237
 10,064
 9,505
 56,806
 (56,806)

 708
 (3,917)
 (3,209)
 (60,015)

$

$

 30,042
 6,273
 9,570
 45,885
 (45,885)

$

 7,195  
 3,791  
 (65) 
 10,921  
 (10,921)  

 24 %
 60 %
 (1)%
 24 %
 24 %

 1,263
 (1,767)
 (504)
 (46,389)

 (555) 
 (2,150) 
 (2,705) 
$  (13,626)  

 (44)%
 122 %
 537 %
 29 %

Research and development expenses primarily consist of personnel related expenses, including salaries, benefits, travel, and other related expenses, stock-based
compensation, payments made to third parties for license, sponsored research and milestone costs related to in-licensed products and technology, payments made
to  third  party  contract  research  organizations  for  preclinical  and  clinical  studies,  investigative  sites  for  clinical  trials,  consultants,  the  cost  of  acquiring  and
manufacturing clinical trial materials, costs associated with regulatory filings, laboratory costs and other supplies.

Research and development expense increased by approximately $7.2 million from $30.0 million for the year ended December 31, 2019 to $37.2 million for the
year  ended  December  31,  2020.  The  increase  in  research  and  development  expense  for  the  year  ended  December  31,  2020  was  primarily  attributable  to  the
following:

●

$2.9 million for increased research and development employee compensation costs, including stock compensation, as we continue to increase research
and development headcount to support development of our clinical programs;

●

$2.5 million for increased lentiviral vector manufacturing to support Mustang-sponsored clinical trials;

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●

●

●

$1.6 million for increased costs for sponsored research and clinical trial agreements with our academic partners;

approximately $1.4 million for increased other costs including consulting, outside services, laboratory supplies and depreciation; and

offset by approximately $1.2 million for decreased costs for third-party contract research organizations.

Research and development expenses - licenses acquired increased by $3.8 million from $6.3 million for the year ended December 31, 2019 to $10.1 million for
the year ended December 31, 2020. The increase in research and development expenses - licenses acquired for the year ended December 31, 2020 was primarily
attributable to the following:

● Approximately $2.7 million for the annual stock dividend to Fortress;

●

●

●

●

$1.3 million related to our licenses with COH;

$0.3 million related to our CD20 license with Fred Hutch;

$0.1 million related to our LentiBOOSTTM license with SIRION; and

offset by approximately $0.5 million for decreased costs related to our licenses with Nationwide, UCLA and CSL Behring (Calimmune).

We expect our research and development activities to increase as we develop our existing product candidates and potentially acquire new product candidates,
reflecting increasing costs associated with the following:

●

●

●

●

●

●

employee-related expenses, which include salaries and benefits;

license fees and milestone payments related to in-licensed products and technology;

expenses  incurred  under  agreements  with  contract  research  organizations,  investigative  sites  and  consultants  that  conduct  our  clinical  trials  and  our
preclinical activities;

facility expenses, which include rent, utilities and maintenance costs;

the cost of acquiring and manufacturing clinical trial materials; and

costs associated with non-clinical activities, and regulatory approvals.

General and Administrative Expenses

General  and  administrative  expenses  consist  primarily  of  salaries  and  related  expenses,  including  stock-based  compensation,  for  executives  and  other
administrative personnel, recruitment expenses, professional fees and other corporate expenses, including investor relations, legal activities including patent fees,
and facilities-related expenses.

General and administrative expense decreased by approximately $0.1 million from $9.6 million for the year ended December 31, 2019 to $9.5 million for the
year ended December 31, 2020. The decrease in general and administrative expense for the year ended December 31, 2020 was primarily attributable to the
following:

●

$0.9 million for increased general and administrative employee compensation costs, including stock compensation, due primarily to additional headcount
to support the Company’s continued growth;

●

offset by approximately $1.0 million for decreased costs primarily for legal and professional fees, consulting fees and state taxes.

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We anticipate general and administrative expenses will increase in future periods, reflecting continued and increasing costs associated with:

●

●

●

●

support of our expanded research and development activities, including additional product candidates entering the clinic;

stock compensation granted to key employees and non-employees;

support of business development activities; and

increased professional fees and other costs associated with the regulatory requirements and increased compliance associated with being a publicly traded
company.

Other Income (Expense)

Other income (expense) consists primarily of interest income earned on cash balances and short-term investments and interest expense on the Company’s notes
payable.  For  the  year  ended  December  31,  2020  and  2019,  total  other  income  (expense)  were  approximately  $3.2  million  and  $0.5  million  of  expense,
respectively.  The  $2.7  million  increase  in  other  income  (expense)  for  the  year  ended  December  31,  2020  was  primarily  attributable  to  $1.6  million  of  debt
discount amortization, debt prepayment penalties of $0.6 million and lower interest income of $0.6 million.

Liquidity and Capital Resources

The Company has incurred substantial operating losses and expects to continue to incur significant operating losses for the foreseeable future and may never
become profitable. As of December 31, 2020, the Company had an accumulated deficit of $185.5 million.

The  Company  has  funded  its  operations  to  date  primarily  through  the  sale  of  equity  and  its  venture  debt  financing  agreement  (the  "Loan Agreement")  with
Horizon Technology Finance Corporation ("Horizon"), herein referred to as the "Horizon Notes." In September 2020, we repaid the Horizon Notes in full all
amounts  that  were  outstanding  under  the  loan  agreement,  which  was  comprised  of  $15.0  million  face  value  of  the  outstanding  notes,  $112,500  accrued  and
unpaid interest, a $750,000 loan termination fee and prepayment penalties of $550,000. The Company expects to continue to use the proceeds from previous
financing transactions primarily for general corporate purposes, including financing the Company’s growth, developing new or existing product candidates, and
funding  capital  expenditures,  acquisitions  and  investments.  The  Company  currently  anticipates  that  its  cash  and  cash  equivalents  balances  at  December  31,
2020, are sufficient to fund its anticipated operating cash requirements for at least one year from the date of this Form 10-K.

From January 1, 2021 through March 18, 2021, the Company issued approximately 10.6 million shares of common stock at an average price of $4.24 per share
for gross proceeds of $44.9 million under the ATM Agreement.

The Company will be required to expend significant funds in order to advance the development of its product candidates. The Company will require additional
financings  through  equity  and  debt  offerings,  collaborations  and  licensing  arrangements  or  other  sources  to  fully  develop,  prepare  regulatory  filings,  obtain
regulatory  approvals  and  commercialize  its  existing  and  any  new  product  candidates.  If  the  Company  is  unable  to  arrange  for  such  financings,  or  unable  to
arrange  for  them  on  terms  acceptable  to  the  Company,  the  Company’s  current  development  plans  and  plans  for  expansion  of  its  facility  and  general  and
administrative infrastructure will be curtailed.

Cash Flows for the Years Ended December 31, 2020 and 2019

($in thousands)
Statement of cash flows data:
Total cash (used in) provided by:

Operating activities
Investing activities
Financing activities

Net change in cash, cash equivalents and restricted cash

67

For the year ended December 31, 

2020

2019

$

$

 (37,319)
 (4,412)
 78,122
 36,391

$

$

 (33,581)
 13,909
 65,116
 45,444

    
       
  
 
    
  
 
 
 
 
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Operating Activities

Net  cash  used  in  operating  activities  was  $37.3  million  for  the  year  ended  December  31,  2020,  compared  to  $33.6  million  for  the  year  ended  December  31,
2019. Net cash used in operating activities for the year ended December 31, 2020, was primarily due to approximately $60.0 million in net loss, partially offset
by  $7.6  million  of  common  shares  issuable  for  Founders  shares,  $3.1  million  change  in  operating  assets  and  liabilities,  $3.0  million  of  non-cash  stock
compensation expenses, $2.5 million of research and development-licenses acquired, $2.4 million of equity fee on issuance of common shares to Fortress, $2.3
million of accretion of debt discount and $1.7 million of depreciation expense.

Net cash used in operating activities for the year ended December 31, 2019, was primarily due to approximately $46.4 million in net loss, partially offset by $4.9
million  of  common  shares  issuable  for  Founders  shares,  $2.7  million  of  non-cash  stock  compensation  expenses,  $1.7  million  of  equity  fee  on  issuance  of
common shares to Fortress, $1.4 million of research and development-licenses acquired, $1.3 million of depreciation expense and $0.7 million of accretion of
debt discount.

Investing Activities

Net cash used in investing activities was $4.4 million for the year ended December 31, 2020, representing $2.5 million in purchases of research and development
licenses and $1.9 million in purchases of fixed assets.

Net cash provided by investing activities was $13.9 million for the year ended December 31, 2019, representing our $17.6 million in maturities of certificates of
deposits, offset by $1.4 million in purchases of research and development licenses and $2.3 million in purchases of fixed assets.

Financing Activities

Net cash provided by financing activities was $78.1 million during the year ended December 31, 2020, gross proceeds of $59.8 million, net of offering costs of
$1.1 million, from the Mustang ATM; gross proceeds of $37.2 million, net of offering costs of $2.4 million, from our June 2020 underwritten public offering
and $0.3 million raised from the issuance of the Company’s common shares in connection with the ESPP, partially offset by the prepayment of the Horizon
Notes of $15.7 million.

Net cash provided by financing activities was $65.1 million during the year ended December 31, 2019, due to net proceeds of $13.6 million from the Horizon
Notes; gross proceeds of $22.5 million, net of offering costs of $0.5 million, from the Mustang ATM; and gross proceeds of $31.6 million, net of offering costs
of $2.1 million, from our May 2019 underwritten public offering.

Item 7A.     Quantitative and Qualitative Disclosures About Market Risks

Not applicable.

Item 8.       Financial Statements and Supplementary Data.

The information required by this Item is set forth in the financial statements and notes thereto beginning at page F-1 of this Annual Report on Form 10-K.

Item 9.      Changes in and Disagreements with Accountants on Accounting and Financial Disclosure.

Not applicable.

Item 9A.      Controls and Procedures.

Disclosure Controls and Procedures

Controls and Procedures

Disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) are designed only to provide reasonable assurance that they will
meet  their  objectives.  Under  the  supervision  and  with  the  participation  of  our  management,  including  our  principal  executive  officer  and  principal  financial
officer, we conducted an evaluation of the effectiveness, as of December 31, 2020, of the design

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and operation of our disclosure controls and procedures, as such term is defined in Exchange Act Rules 13a-15(e) and 15d-15(e). Based on this evaluation, our
principal executive officer and principal financial officer have concluded that, as of such date, our disclosure controls and procedures are effective to ensure that
information required to be disclosed by us in our Exchange Act reports is recorded, processed, summarized, and reported within the time periods specified in the
SEC’s rules and forms, and that such information is accumulated and communicated to our management, including our principal executive officer and principal
financial officer, as appropriate to allow timely decisions regarding required disclosure.

Internal Control over Financial Reporting

Management’s Report on Internal Control over Financial Reporting.

Our  management  is  responsible  for  establishing  and  maintaining  adequate  internal  control  over  financial  reporting,  as  such  term  is  defined  in  Exchange Act
Rules 13a-15(f) and 15d-15(f). Internal control over financial reporting refers to the process designed by, or under the supervision of, our principal executive
officer and principal financial officer, and effected by our Board of Directors, management and other personnel, to provide reasonable assurance regarding the
reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles,
and includes those policies and procedures that:

(1) pertain to the maintenance of records that in reasonable detail accurately and fairly reflect the transactions and dispositions of our assets;

(2) provide  reasonable  assurance  that  transactions  are  recorded  as  necessary  to  permit  preparation  of  financial  statements  in  accordance  with  generally
accepted  accounting  principles  (“GAAP”),  and  that  our  receipts  and  expenditures  are  being  made  only  in  accordance  with  authorization  of  our
management and directors; and

(3) provide reasonable assurance regarding prevention or timely detection of unauthorized acquisitions, use or disposition of our assets that could have a

material effect on the financial statements.

Internal  control  over  financial  reporting  has  inherent  limitations.  Internal  control  over  financial  reporting  is  a  process  that  involves  human  diligence  and
compliance  and  is  subject  to  lapses  in  judgment  and  breakdowns  resulting  from  human  failures.  Internal  control  over  financial  reporting  also  can  be
circumvented by collusion or improper management override. Because of such limitations, there is a risk that material misstatements may not be prevented or
detected on a timely basis by internal control over financial reporting. However, these inherent limitations are known features of the financial reporting process.
Therefore, it is possible to design into the process safeguards to reduce, though not eliminate, this risk.

Our management assessed the effectiveness of our internal control over financial reporting as of December 31, 2020. In making the assessment, management
used the criteria set forth by the Committee of Sponsoring Organizations of the Treadway Commission (“COSO”) in Internal Control - Integrated Framework
(2013).

Based  on  our  assessment,  our  management  has  concluded  that,  as  of  December  31,  2020,  our  internal  controls  over  financial  reporting  were  effective  based
upon those criteria.

Changes in Internal Controls over Financial Reporting.

There were no changes in our internal control over financial reporting during our most recent fiscal quarter that have materially affected, or are reasonably likely
to materially affect, our internal control over financial reporting.

Item 9B.     Other Information

None.

Item 10.     Directors, Executive Officers and Corporate Governance

PART III

The information required by this Item is incorporated herein by reference from our Proxy Statement for our 2021 Annual Meeting of Stockholders.

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Table of Contents

Item 11.     Executive Compensation

The information required by this Item is incorporated herein by reference from our Proxy Statement for our 2021 Annual Meeting of Stockholders.

Item 12.     Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters

The information required by this Item is incorporated herein by reference from our Proxy Statement for our 2021 Annual Meeting of Stockholders.

Item 13.      Certain Relationships and Related Transactions, and Director Independence.

The information required by this Item is incorporated herein by reference from our Proxy Statement for our 2021 Annual Meeting of Stockholders.

Item 14.     Principal Accounting Fees and Services.

The information required by this Item is incorporated herein by reference from our Proxy Statement for our 2021 Annual Meeting of Stockholders.

PART IV

Item 15.     Exhibits, Financial Statement Schedules.

(a) Financial Statements.

The following financial statements are filed as part of this Form 10-K:

Report of Independent Registered Public Accounting Firm

Financial Statements:
Balance Sheets as of December 31, 2020 and 2019
Statements of Operations for the Years Ended December 31, 2020 and 2019
Statements of Changes in Stockholders’ Equity for the Years Ended December 31, 2020 and 2019
Statements of Cash Flows for the Years Ended December 31, 2020 and 2019
Notes to Financial Statements

F-2

F-3
F-4
F-5
F-6
F-7 - F-30

(b) Exhibits.

Exhibit No.
3.1

3.2

3.3

Amended and Restated Certificate of Incorporation of Mustang Bio, Inc. (formerly Mustang Therapeutics, Inc.), dated July 26, 2016. *
Filed as Exhibit 3.1 on the Company’s Form 1012G filed on July 28, 2016.

Description

  Certificate of Amendment of the Amended and Restated Certificate of Incorporation of Mustang Bio, Inc., dated June 14, 2018. *
  Filed as Exhibit 3.1 on the Company’s Form 10-Q filed on August 13, 2018. 

  Certificate of Amendment of the Amended and Restated Certificate of Incorporation of Mustang Bio, Inc., dated September 30, 2019. *
  Filed as Exhibit 3.1 on the Company’s Form 8-K filed on September 30, 2019.

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Exhibit No.

Description

3.4

3.5

4.1

4.2

4.3

10.1

10.2

10.3

10.4

10.5

10.6

10.7

10.8

10.9

10.10

10.11

Certificate of Amendment of the Amended and Restated Certificate of Incorporation of Mustang Bio, Inc., dated
December 4, 2020. *
Filed as Exhibit 3.1 on the Company’s Form 8K filed on December 4, 2020.

  Bylaws of Mustang Bio, Inc. *

Filed as Exhibit 3.2 on the Company’s Form 1012G filed on July 28, 2016.

Specimen certificates evidencing shares of common stock, Class A common stock and Class A preferred stock. *
Filed as Exhibit 4.1 on the Company’s Form 1012G filed on July 28, 2016.

Form of warrant agreement.*
Filed as Exhibit 4.2 on the Company’s Form 1012G filed on July 28, 2016.

  Description of Securities of Mustang Bio, Inc. **

Second Amended and Restated Founders Agreement between Fortress Biotech, Inc. and Mustang Bio, Inc., dated July 26, 2016. *
Filed as Exhibit 10.1 on the Company’s Form 1012G filed on July 28, 2016.

Management Services Agreement between Fortress Biotech, Inc. and Mustang Bio, Inc., dated March 13, 2015. *
Filed as Exhibit 10.2 on the Company’s Form 1012G filed on July 28, 2016.

Future Advance Promissory Note to Fortress Biotech, Inc., dated May 5, 2016. *
Filed as Exhibit 10.3 on the Company’s Form 1012G filed on July 28, 2016.

Promissory Note to NSC Biotech Venture Fund I, LLC, dated July 5, 2016. *
Filed as Exhibit 10.4 on the Company’s Form 1012G filed on July 28, 2016.

Common Stock Warrant issued by Mustang Bio, Inc. to NSC Biotech Venture Fund I, LLC, dated July 5, 2016. *
Filed as Exhibit 10.5 on the Company’s Form 1012G filed on July 28, 2016.

License Agreement by and between Mustang Bio, Inc. and City of Hope, dated March 17, 2015. #
Filed as Exhibit 10.6 on the Company’s Form 1012G filed on July 28, 2016.

Sponsored Research Agreement by and between Mustang Bio, Inc. and City of Hope, dated March 17, 2015. *
Filed as Exhibit 10.7 on the Company’s Form 1012G filed on July 28, 2016.

Mustang Bio, Inc. 2016 Incentive Plan. †*
Filed as Exhibit 10.8 on the Company’s Form 1012G filed on July 28, 2016.

Non-Employee Directors Compensation Plan. †*
Filed as Exhibit 10.9 on the Company’s Form 1012G filed on July 28, 2016.

Agreement with Chord Advisors, LLC, dated April 8, 2016. *
Filed as Exhibit 10.10 on the Company’s Form 1012G filed on July 28, 2016.

Agreement with Caribe BioAdvisors, LLC, dated January 1, 2017.
Filed as Exhibit 10.11 on the Company’s Form 10K filed on March 31, 2017.

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Exhibit No.
10.12

Exclusive License Agreement with The Regents of the University of California, dated March 17, 2017. #
Filed as Exhibit 10.4 on the Company’s Form 10Q filed on August 14, 2017.

Description

10.13

  Exclusive License Agreement - IV/ICV with City of Hope, dated February 17, 2017. #

Filed as Exhibit 10.5 on the Company’s Form 10Q filed on August 14, 2017.

10.14

  Amended and Restated Exclusive License Agreement - CD123 with City of Hope, dated February 17, 2017. #

Filed as Exhibit 10.14 on the Company’s Form 10K filed on March 31, 2017.

10.15

  Amended and Restated Exclusive License Agreement - IL13Ra2 with City of Hope, dated February 17, 2017. #

Filed as Exhibit 10.15 on the Company’s Form 10K filed on March 31, 2017.

10.16

  Amended and Restated Exclusive License Agreement - Spacer with City of Hope, dated February 17, 2017. #

Filed as Exhibit 10.16 on the Company’s Form 10K filed on March 31, 2017.

10.17

  Employment Agreement between Manuel Litchman and Mustang Bio, Inc., made effective as of April 24, 2017

Filed as Exhibit 10.1 on the Company’s Form 8K filed on April 24, 2017.

10.18

  License Agreement dated May 31, 2017 by and between Mustang Bio, Inc. and City of Hope (CSI). #

Filed as Exhibit 10.1 on the Company’s Form 10Q/A filed on November 14, 2017.

10.19

  License Agreement dated May 31, 2017 by and between Mustang Bio, Inc. and City of Hope (PSCA). #

Filed as Exhibit 10.2 on the Company’s Form 10Q/A filed on November 14, 2017.

10.20

  License Agreement dated May 31, 2017 by and between Mustang Bio, Inc. and City of Hope (HER2). #

Filed as Exhibit 10.3 on the Company’s Form 10Q/A filed on November 14, 2017.

10.21

  Lease Agreement, by and between the Company and WCS - 377 Plantation Street, Inc., dated October 27, 2017.

Filed as Exhibit 10.1 on the Company’s Form 10Q filed on November 14, 2017.

10.22

  Venture Loan and Security Agreement, dated March 29, 2019, by and between the Company and Horizon Technology Finance Corporation. *

Filed as Exhibit 10.1 on the Company’s Form 8K filed on April 4, 2019.

10.23

  Mustang Bio, Inc. 2019 Employee Stock Purchase Plan†*

Filed as Exhibit 10.1 on the Company’s Form 10-Q filed on August 9, 2019.

23.1

24.1

31.1

31.2

Consent of Independent Registered Public Accounting Firm, BDO USA, LLP

  Power of Attorney (included on signature page).

  Certification of President and Chief Executive Officer, pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.

  Certification of Principal Financial Officer, pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.

72

 
 
 
   
 
   
 
   
 
   
 
   
 
   
 
   
 
   
 
   
 
   
 
   
 
   
 
   
 
   
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Exhibit No.
32.1

32.2

101

104

Certification of President and Chief Executive Officer, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the
Sarbanes-Oxley Act of 2002.

Description

Certification of Principal Financial Officer, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act
of 2002.

The following financial information from Mustang Bio, Inc.’s Annual Report on Form 10-K for the year ended December 31, 2020, formatted
in Inline Extensible Business Reporting Language (iXBRL): (i) the Balance Sheets, (ii) the Statements of Operations, (iii) the Statement of
Stockholders’ Equity, (iv) the Statements of Cash Flows, and (v) Notes to the Financial Statements (filed herewith).
Cover Page Interactive Data File (formatted as Inline XBRL and contained in exhibit 101)

#     Confidential treatment has been granted with respect to omitted portions of this exhibit.

†     Indicates management contract or compensatory plan or arrangement.

*     Previously Filed.

**   Filed herewith.

Item 16.      Form 10-K Summary.

None.

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INDEX TO FINANCIAL STATEMENTS

Report of Independent Registered Public Accounting Firm
Balance Sheets as of December 31, 2020 and 2019
Statements of Operations for the Years Ended December 31, 2020 and 2019
Statements of Changes in Stockholders’ Equity for the Years Ended December 31, 2020 and 2019
Statements of Cash Flows for the Years Ended December 31, 2020 and 2019
Notes to Financial Statements

F-2
F-3
F-4
F-5
F-6
F-7 – F-30

F-1

Table of Contents

Report of Independent Registered Public Accounting Firm

Shareholders and Board of Directors
Mustang Bio, Inc.
New York, New York

Opinion on the Financial Statements

We  have  audited  the  accompanying  balance  sheets  of  Mustang  Bio,  Inc.  (the  “Company”)  as  of  December  31,  2020  and  2019,  the  related  statements  of
operations, stockholders’ equity, and cash flows for each of the two years in the period ended December 31, 2020, and the related notes (collectively referred to
as the “financial statements”). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Company at December
31, 2020 and 2019, and the results of its operations and its cash flows for each of the two years in the period ended December 31, 2020, in conformity with
accounting principles generally accepted in the United States of America.

Basis for Opinion

These  financial  statements  are  the  responsibility  of  the  Company’s  management.  Our  responsibility  is  to  express  an  opinion  on  the  Company’s  financial
statements based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (“PCAOB”)
and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of
the Securities and Exchange Commission and the PCAOB.

We  conducted  our  audits  in  accordance  with  the  standards  of  the  PCAOB.  Those  standards  require  that  we  plan  and  perform  the  audit  to  obtain  reasonable
assurance about whether the financial statements are free of material misstatement, whether due to error or fraud. The Company is not required to have, nor were
we  engaged  to  perform,  an  audit  of  its  internal  control  over  financial  reporting. As  part  of  our  audits  we  are  required  to  obtain  an  understanding  of  internal
control over financial reporting but not for the purpose of expressing an opinion on the effectiveness of the Company’s internal control over financial reporting.
Accordingly, we express no such opinion.

Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing
procedures that respond to those risks. Such procedures included examining, on a test  basis,  evidence  regarding  the  amounts  and  disclosures  in  the  financial
statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall
presentation of the financial statements. We believe that our audits provide a reasonable basis for our opinion.

 We have served as the Company's auditor since 2016.

/s/ BDO USA, LLP

Boston, Massachusetts
March 24, 2021

F-2

 
  
  
  
 
 
 
 
 
Table of Contents

MUSTANG BIO, INC.
BALANCE SHEETS
(in thousands, except for share and per share amounts)

December 31, 
2020

December 31, 
2019

ASSETS
Current Assets:

Cash and cash equivalents
Other receivables - related party
Prepaid expenses and other current assets

Total current assets

Property, plant and equipment, net
Fixed assets - construction in process
Restricted cash
Other assets
Operating lease right-of-use asset, net
Total Assets

LIABILITIES AND STOCKHOLDERS’ EQUITY
Current Liabilities:

Accounts payable and accrued expenses
Payables and accrued expenses - related party
Short-term notes payable
Operating lease liabilities - short-term

Total current liabilities

Notes payable
Operating lease liabilities - long-term
Total Liabilities

Commitments and Contingencies

Stockholders’ Equity
Preferred stock ($0.0001 par value), 2,000,000 shares authorized, 250,000 shares of Class A preferred
stock issued and outstanding as of December 31, 2020 and December 31, 2019, respectively
Common Stock ($0.0001 par value), 125,000,000 shares authorized

Class A common shares, 845,385 shares issued and outstanding as of December 31, 2020 and
December 31, 2019, respectively
Common shares, 70,920,693 and 39,403,519 shares issued and outstanding as of December 31, 2020
and December 31, 2019, respectively

Common stock issuable, 2,103,122 and 1,206,667 shares as of December 31, 2020 and
December 31, 2019, respectively
Additional paid-in capital
Accumulated deficit
Total Stockholders’ Equity
Total Liabilities and Stockholders’ Equity

$

$

$

$

$

$

$

97,804
15
1,715
99,534

7,529
499
1,000
250
1,088
109,900

8,747
490
—
278
9,515

—
1,950
11,465

—

—

7

61,413
19
1,631
63,063

6,779
1,157
1,000
250
1,196
73,445

5,668
596
1,250
257
7,771

12,179
1,843
21,793

—

—

4

7,939
275,963
(185,474)
98,435
109,900

$

4,923
172,184
(125,459)
51,652
73,445

The accompanying notes are an integral part of these financial statements.

F-3

    
    
 
   
  
 
   
  
 
 
 
 
 
 
 
  
 
  
 
 
 
 
 
 
 
 
 
  
 
  
 
  
 
  
 
  
 
  
 
 
 
 
 
  
 
  
 
 
 
  
 
  
 
  
 
  
 
  
 
  
 
  
 
  
 
 
 
  
 
  
 
 
 
 
 
 
 
 
 
 
 
 
Table of Contents

MUSTANG BIO, INC.
STATEMENTS OF OPERATIONS
(in thousands, except for share and per share amounts)

Operating expenses:

Research and development
Research and development – licenses acquired
General and administrative

Total operating expenses
Loss from operations

Other income (expense)

Interest income
Interest expense

Total other income (expense)
Net Loss

Net loss per common share outstanding, basic and diluted

For the year ended December 31, 

2020

2019

$

$

$

$

37,237
10,064
9,505
56,806
(56,806)

708
(3,917)
(3,209)
(60,015) $

30,042
6,273
9,570
45,885
(45,885)

1,263
(1,767)
(504)
(46,389)

(1.14) $

(1.29)

Weighted average number of common shares outstanding, basic and diluted

52,588,781

36,061,811

The accompanying notes are an integral part of these financial statements.

F-4

    
    
 
    
  
 
 
 
 
 
 
 
 
 
  
 
  
 
  
 
  
 
 
 
 
 
 
 
 
  
 
  
 
  
 
 
Class A Common Shares
     Amount

Shares
1,000,000

$
—  
—  

Common Shares

Shares
26,610,183

$
—  

     Amount
$
3
—  
—  

Common
Stock
Issuable
2,085
4,923
(2,085)

Additional
Paid-in
     Capital

Accumulated
Deficit

Total
Stockholders’
Equity 

$

113,378

$
—  

2,085

(79,070)

$
—  
—  

36,396
4,923
—

Table of Contents

MUSTANG BIO, INC.
STATEMENTS OF STOCKHOLDERS’ EQUITY
(in thousands, except share amounts)

Class A Preferred Stock
     Amount

     Shares

Balances at December 31, 2018
Common stock issuable - Founders Agreement
Issuance of common shares - Founders Agreement  
Issuance of common shares - Equity fee on
Horizon Notes to Fortress Biotech
Issuance of warrants - Horizon Notes
Conversion of Class A common shares to
common shares
Issuance of common shares, net of offering costs -
At-the-Market Offering
Issuance of common shares - Equity fee on At-the-
Market Offering
Issuance of common shares, net of offering costs -
Public Offering
Issuance of common shares - Equity fee on Public
Offering
Stock-based compensation expenses
Exercise of warrants
Net loss
Balances at December 31, 2019
Common stock issuable - Founders Agreement
Issuance of common shares - Founders Agreement  
Issuance of common shares, net of offering costs -
At-the-Market Offering
Issuance of common shares - Equity fee on At-the-
Market Offering
Issuance of common shares, net of offering costs -
Public Offering
Issuance of common shares - Equity fee on Public
Offering
Issuance of common shares under ESPP
Stock-based compensation expenses
Exercise of warrants
Net loss
Balances at December 31, 2020

250,000

$
—  
—  

—
—

—

—

—

—

—
—  
—  
—  
$
—  
—  

250,000

—

—

—

—
—
—  
—  
—  
$

250,000

—  
—  
—  

—
—

—

—

—

—

—
—  
—  
—  
—  
—  
—  

—

—

—

—
—
—  
—  
—  
—  

—
—

(154,615)

—

—

—

—
—  
—  
—  
$
—  
—  

845,385

—

—

—

—
—
—  
—  
—  
$

845,385

—  
—  
—  

—
—

—

—

—

—

—
—  
—  
—  
—  
—  
—  

—

—

—

—
—
—  
—  
—  
—  

709,314

108,069
—

154,615

3,506,222

87,656

7,906,250

197,656
30,341
93,213

39,403,519

—  
$
—  

1,206,667

17,579,097

342,773

11,455,604

286,390
140,856
502,788
2,999

—  
$

70,920,693

The accompanying notes are an integral part of these financial statements.

F-5

—
—

—

—

—

1

—
—

—

—

—

—

—
—  
—  
—  
4
$
—  
—  

—
—  
—  
—  
$

4,923
7,577
(4,923)

2

—

1

—

362

—

—
—
—  
—  
—  
$
7

—
—
—  
—  
—  
$

7,939

375
888

—

21,972

495

29,536

791
2,664

—  
—  
$
—  

172,184

4,923

58,595

1,152

34,841

932
349
2,987

—  
—  
$

275,963

—
—

—

—

—

—

—
—  
—  

(46,389)
(125,459)

$
—  
—  

—

—

—

—
—
—  
—  

(60,015)
(185,474)

$

375
888

—

21,972

495

29,537

791
2,664
—
(46,389)
51,652
7,577
—

58,597

1,514

34,842

932
349
2,987
—
(60,015)
98,435

    
    
    
    
    
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Table of Contents

MUSTANG BIO, INC.
STATEMENTS OF CASH FLOWS
(in thousands)

Cash Flows from Operating Activities:
Net loss
Adjustments to reconcile net loss to net cash used in operating activities:
Accretion of debt discount
Issuance of common shares - Equity fee on At-the-Market Offering to Fortress Biotech
Issuance of common shares - Equity fee on Public Offering to Fortress Biotech
Issuance of common shares - Equity fee on Horizon Notes to Fortress Biotech
Common shares issuable for Founders Agreement
Research and development - licenses acquired
Stock-based compensation expenses
Depreciation expense
Amortization of operating lease right-of-use assets

Changes in operating assets and liabilities:
Prepaid expenses and other current assets
Other receivables - related party
Accounts payable and accrued expenses
Payable and accrued expenses - related party
Lease liabilities

Net cash used in operating activities

Cash Flows from Investing Activities:

Maturity of certificate of deposit
Purchase of research and development licenses
Purchase of fixed assets

Net cash (used in) provided by investing activities

Cash Flows from Financing Activities:

Proceeds from Horizon Notes
Debt issuance costs
Proceeds from issuance of common shares - At-the-Market Offering
Offering costs for the issuance of common shares - At-the-Market Offering
Proceeds from issuance of common shares - Public Offering
Offering costs for the issuance of common shares - Public Offering
Repayment of notes payable
Proceeds from issuance of common shares under ESPP

Net cash provided by financing activities

Net change in cash, cash equivalents and restricted cash
Cash, cash equivalents and restricted cash, beginning of the period
Cash, cash equivalents and restricted cash, end of the period

Supplemental disclosure of cash flow information:
Cash paid for interest

Supplemental disclosure of noncash investing and financing activities:
Fixed assets (acquired but not paid)
Issuance of common shares - Founders Agreement
Offering costs for the issuance of common shares - At-the-Market Offering, in accounts payable and
accrued expenses
Issuance of warrants - Horizon Notes

For the year ended December 31, 
2019
2020

$

(60,015)

$

(46,389)

2,321
1,514
932
—
7,577
2,487
2,987
1,677
108

(84)
4
3,151
(106)
128
(37,319)

—
(2,487)
(1,925)
(4,412)

—
—
59,805
(1,124)
37,230
(2,388)
(15,750)
349
78,122

36,391
62,413
98,804

1,593

31
4,923

84
—

$

$

$
$

$
$

710
495
791
375
4,923
1,350
2,664
1,258
110

(558)
(19)
296
360
53
(33,581)

17,604
(1,350)
(2,345)
13,909

15,000
(1,393)
22,515
(543)
31,625
(2,088)
—
—
65,116

45,444
16,969
62,413

1,057

187
2,085

—
888

$

$

$
$

$
$

The accompanying notes are an integral part of these financial statements.

F-6

    
    
 
    
  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  
 
 
 
 
 
 
 
 
 
  
 
  
 
  
 
  
 
 
 
 
 
 
 
 
 
  
 
  
 
  
 
  
 
 
 
 
 
  
 
  
 
 
 
 
 
  
 
  
 
  
 
  
 
  
 
  
 
  
 
  
Table of Contents

Notes to Financial Statements

Note 1 - Organization and Description of Business

Mustang  Bio,  Inc.  (the  “Company”  or  “Mustang”)  was  incorporated  in  Delaware  on  March  13,  2015.  Mustang  is  as  a  clinical-stage
biopharmaceutical  company  focused  on  translating  today’s  medical  breakthroughs  in  cell  and  gene  therapy  into  potential  cures  for
hematologic cancers, solid tumors and rare genetic diseases. The Company may acquire rights to these technologies by licensing the rights
or otherwise acquiring an ownership interest in the technologies, funding their research and development and eventually either out-licensing
or bringing the technologies to market.

The Company is a majority-controlled subsidiary of Fortress Biotech, Inc. (“Fortress” or “Parent”).

Liquidity and Capital Resources

The  Company  has  incurred  substantial  operating  losses  and  expects  to  continue  to  incur  significant  operating  losses  for  the  foreseeable
future and may never become profitable. As of December 31, 2020, the Company had an accumulated deficit of $185.5 million.

The Company has funded its operations to date primarily through the sale of equity and its venture debt financing agreement (the "Loan
Agreement") with Horizon Technology Finance Corporation ("Horizon"), herein referred to as the "Horizon Notes." In September 2020, we
repaid the Horizon Notes in full all amounts that were outstanding under the loan agreement, which was comprised of $15.0 million face
value  of  the  outstanding  notes,  $112,500  accrued  and  unpaid  interest,  a  $750,000  loan  termination  fee  and  prepayment  penalties  of
$550,000.  The  Company  expects  to  continue  to  use  the  proceeds  from  previous  financing  transactions  primarily  for  general  corporate
purposes,  including  financing  the  Company’s  growth,  developing  new  or  existing  product  candidates,  and  funding  capital  expenditures,
acquisitions  and  investments.  The  Company  currently  anticipates  that  its  cash  and  cash  equivalents  balances  at  December  31,  2020,  are
sufficient to fund its anticipated operating cash requirements for at least one year from the date of this Form 10-K.

The Company will be required to expend significant funds in order to advance the development of its product candidates. The Company
will  require  additional  financings  through  equity  and  debt  offerings,  collaborations  and  licensing  arrangements  or  other  sources  to  fully
develop, prepare regulatory filings, obtain regulatory approvals and commercialize its existing and any new product candidates.In addition
to  the  foregoing,  based  on  the  Company’s  current  assessment,  the  Company  does  not  expect  any  material  impact  on  its  long-term
development timeline and its liquidity due to the worldwide spread of the COVID-19 virus. However, the Company is continuing to assess
the effect on its operations by monitoring the spread of COVID-19 and the actions implemented to combat the virus throughout the world.

Note 2 - Significant Accounting Policies

Basis of Presentation

The Company’s financial statements have been prepared in conformity with accounting principles generally accepted in the United States of
America (“GAAP”). The Company has no subsidiaries.

All inter-company transactions between Fortress and Mustang are classified as due from or due to related party in the financial statements.
The Company believes that the assumptions underlying the financial statements are reasonable.

Segments

Operating segments are defined as components of an enterprise about which separate discrete information is available for evaluation by the
chief  operating  decision  maker,  or  decision-making  group,  in  deciding  how  to  allocate  resources  and  in  assessing  performance.  The
Company views its operations and manages its business in one operating and reporting segment.

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Use of Estimates

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the
reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the
reported amounts of expenses during the reporting period. Actual results could differ from those estimates.

Cash and Cash Equivalents

The Company considers all short-term investments with an original maturity of three months or less when purchased to be cash equivalents.
Cash and cash equivalents at December 31, 2020 and 2019, consisted of cash and money market funds in institutions in the United States.
Balances at certain institutions have exceeded Federal Deposit Insurance Corporation (“FDIC”) insured limits.

Other Receivables – Related Party

Other  receivables  includes  amounts  due  to  the  Company  from  Fortress  and  Journey  Medical  Corporation,  both  related  parties,  and  is
recorded at the invoiced amount.

Restricted Cash

The Company records cash held in an escrow account as a security deposit for the manufacturing facility in Worcester, Massachusetts, as
restricted cash. The Company had $1.0 million in restricted cash as of December 31, 2020 and 2019, respectively. The Facility initiated cell
processing operations for personalized CAR T and gene therapies in 2018.

Property, plant and equipment, net

Property and equipment, net, which consists mainly of laboratory equipment, are carried at cost less accumulated depreciation. Depreciation
is computed over the estimated useful lives of the respective assets, generally five years, using the straight-line method.

Property and equipment - Construction in Process

In connection with the Company’s cell processing facility, the Company incurred costs for the design and construction of the facility and the
purchase  of  equipment;  $0.5  million  and  $1.2  million  are  recorded  in  fixed  assets  -  construction  in  process  on  the  balance  sheet  at
December 31, 2020 and 2019, respectively. Upon completion of the facility’s construction, all costs associated with the buildout will be
recorded as leasehold improvements and amortized over the shorter of the estimated useful lives or the term of the respective leases, upon
the improvement being placed in service.

Research and Development Costs

Research and development costs are expensed as incurred. Advance payments for goods and services that will be used in future research
and development activities are expensed when the activity has been performed or when the goods have been received rather than when the
payment is made. Upfront and milestone payments due to third parties that perform research and development services on the Company’s
behalf will be expensed as services are rendered or when the milestone is achieved.

Research  and  development  costs  primarily  consist  of  personnel  related  expenses,  including  salaries,  benefits,  travel,  and  other  related
expenses,  stock-based  compensation,  payments  made  to  third  parties  for  license  and  milestone  costs  related  to  in-licensed  products  and
technology, payments made to third party contract research organizations for preclinical and clinical studies, investigative sites for clinical
trials, consultants, the cost of acquiring and manufacturing clinical trial materials, costs associated with regulatory filings, laboratory costs
and other supplies.

In  accordance  with  Accounting  Standards  Codification  (“ASC”)  730-10-25-1, Research  and  Development, costs  incurred  in  obtaining
technology licenses are charged to research and development expense if the technology licensed has not reached commercial feasibility and
has no alternative future use. The licenses purchased by the Company require

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Table of Contents

substantial completion of research and development, regulatory and marketing approval efforts to reach commercial feasibility and has no
alternative  future  use. Accordingly,  the  total  purchase  price  for  the  licenses  acquired  is  reflected  as  research  and  development  -  licenses
acquired in the Company’s Statements of Operations.

Annual Stock Dividend

In  July  2016,  in  connection  with  the Amended  and  Restated Articles  of  Incorporation,  the  Company  issued 250,000  Class A  preferred
shares to Fortress. The Class A preferred shares entitle the holder to a stock dividend equal to 2.5% of the fully diluted outstanding equity of
the  Company  (“The Annual  Stock  Dividend”).  The Annual  Stock  Dividend  was  part  of  the  consideration  payable  for  formation  of  the
Company and the identification of certain assets, including the license contributed to Mustang by Fortress (see Note 4).

In June 2018, in connection with the Amended and Restated Articles of Incorporation, the Company amended the annual stock dividend
due date from March 13th to January 1st.

Pursuant to the Amended and Restated Articles of Incorporation, the Company issued 1,206,667 shares of common stock to Fortress for the
Annual Stock Dividend, representing 2.0%, on a pro rata basis, of the fully-diluted outstanding equity of Mustang on January 1, 2020. This
was  shown  in  the  Statement  of  Stockholders’  Equity  at  December  31,  2019,  as  Common  stock  issuable  –  Founders  Agreement.  The
Company  recorded  an  expense  of  approximately  $4.9  million  in  research  and  development  -  licenses  acquired  related  to  these  issuable
shares during the year ended December 31, 2019.

Pursuant to the Amended and Restated Articles of Incorporation, the Company issued 2,001,490 shares of common stock to Fortress for the
Annual Stock Dividend, representing 2.5% of the fully-diluted outstanding equity of Mustang on January 1, 2021. This was shown in the
Statement  of  Stockholders’  Equity  at  December  31,  2020  as  Common  stock  issuable  -  Founders Agreement.  The  Company  recorded  an
expense  of  approximately  $7.6  million  in  research  and  development  –  licenses  acquired  related  to  these  issuable  shares  during  the  year
ended December 31, 2020.

Fair Value Measurement

The  Company  follows  accounting  guidance  on  fair  value  measurements  for  financial  assets  and  liabilities  measured  at  fair  value  on  a
recurring basis. Under the accounting guidance, fair value is defined as an exit price, representing the amount that would be received to sell
an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. As such, fair value is a
market-based  measurement  that  should  be  determined  based  on  assumptions  that  market  participants  would  use  in  pricing  an  asset  or  a
liability.

The accounting guidance requires fair value measurements be classified and disclosed in one of the following three categories:

Level 1:    Quoted prices in active markets for identical assets or liabilities.

Level  2:        Observable  inputs  other  than  Level  1  prices,  for  similar  assets  or  liabilities  that  are  directly  or  indirectly  observable  in  the

marketplace.

Level  3:        Unobservable  inputs  which  are  supported  by  little  or  no  market  activity  and  that  are  financial  instruments  whose  values  are
determined  using  pricing  models,  discounted  cash  flow  methodologies,  or  similar  techniques,  as  well  as  instruments  for  which  the
determination of fair value requires significant judgment or estimation.

The fair value hierarchy also requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when
measuring fair value. Assets and liabilities measured at fair value are classified in their entirety based on the lowest level of input that is
significant to the fair value measurement. The Company’s assessment of the significance of a particular input to the fair value measurement
in its entirety requires management to make judgments and consider factors specific to the asset or liability.

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Leases

Effective  January  1,  2019,  the  Company  accounts  for  its  leases  under ASC  842, Leases.  Under  this  guidance,  arrangements  meeting  the
definition of a lease are classified as operating or financing leases and are recorded on the balance sheet as both a right of use asset and lease
liability, calculated by discounting fixed lease payments over the lease term at the rate implicit in the lease or the Company's incremental
borrowing rate. Lease liabilities are increased by interest and reduced by payments each period, and the right of use asset is amortized over
the lease term. For operating leases, interest on the lease liability and the amortization of the right of use asset result in straight-line rent
expense over the lease term. Variable lease expenses are recorded when incurred. In calculating the right of use asset and lease liability, the
Company elects to combine lease and non-lease components. The Company excludes short-term leases having initial terms of 12 months or
less from the new guidance as an accounting policy election and recognizes rent expense on a straight-line basis over the lease term.

Stock-Based Compensation

The  Company  expenses  stock-based  compensation  to  employees  over  the  requisite  service  period  based  on  the  estimated  grant-date  fair
value of the awards and forfeiture rates.

 For  stock-based  compensation  awards  to  non-employees,  prior  to  the  adoption  of  ASU  2018-07  on  January  1,  2019,  the  Company
remeasured the fair value of the non-employee awards at each reporting period prior to vesting and finally at the vesting date of the award.
Changes  in  the  estimated  fair  value  of  these  non-employee  awards  were  recognized  as  compensation  expense  in  the  period  of  change.
Subsequent to the adoption of ASU 2018-07, the Company recognizes non-employee compensation costs over the requisite service period
based on a measurement of fair value for each stock award.

The  Company  estimates  the  fair  value  of  stock  option  grants  using  the  Black-Scholes  option  pricing  model  or  409a  valuations,  as
applicable. The assumptions used in calculating the fair value of stock-based awards represent management’s best estimates and involve
inherent uncertainties and the application of management’s judgment.

Income Taxes

The Company records income taxes using the asset and liability method. Deferred income tax assets and liabilities are recognized for the
future tax effects attributable to temporary differences between the financial statement carrying amounts of existing assets and liabilities
and their respective income tax bases, and operating loss and tax credit carryforwards. The Company establishes a valuation allowance if
management  believes  it  is  more  likely  than  not  that  the  deferred  tax  assets  will  not  be  recovered  based  on  an  evaluation  of  objective
verifiable  evidence.  For  tax  positions  that  are  more  likely  than  not  of  being  sustained  upon  audit,  the  Company  recognizes  the  largest
amount of the benefit that is greater than 50% likely of being realized. For tax positions that are not more likely than not of being sustained
upon audit, the Company does not recognize any portion of the benefit.

Net Loss per Share

Net loss per share is computed by dividing net loss by the weighted average number of common shares outstanding during the period less
unvested  restricted  stock.  Since  dividends  are  declared,  paid  and  set  aside  among  the  holders  of  shares  of  common  stock  and  Class A
common shares pro-rata on an as-if-converted basis, the two-class method of computing net loss per share is not required. Diluted net loss
per share does not reflect the effect of shares of common stock to be issued upon the exercise of warrants or outstanding Class A preferred
shares, as their inclusion would be anti-dilutive.

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The table below summarizes potentially dilutive securities that were not considered in the computation of diluted net loss per share because
they would be anti-dilutive.

Warrants
Options
Class A Preferred Shares
Unvested restricted stock awards
Unvested restricted stock units
Total

Comprehensive Loss

For the year ended December 31, 

2020
5,402,670  
1,141,675  
250,000  
302,114  
1,468,559  
8,565,018  

2019
5,405,669
1,241,675
250,000
299,060
1,112,417
8,308,821

The Company has no components of other comprehensive loss, and therefore, comprehensive loss equals net loss.

Recently Adopted Accounting Pronouncements

In December 2019, the FASB issued ASU 2019-12, “Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes”,  which  is
intended to simplify various aspects related to accounting for income taxes. The ASU removes certain exceptions to the general principles
in Topic 740 and also clarifies and amends existing guidance to improve consistent application. This guidance is effective for fiscal years,
and interim periods within those fiscal years, beginning after December 15, 2020, with early adoption permitted. The Company’s adoption
of this standard on January 1, 2020, did not have a material impact on its financial statements and related disclosures.

In  August  2018,  the  FASB  issued  ASU  2018-13,  “Fair  Value  Measurement  (Topic  820),  -  Disclosure  Framework  -  Changes  to  the
Disclosure  Requirements  for  Fair  Value  Measurement”,  which  makes  a  number  of  changes  meant  to  add,  modify  or  remove  certain
disclosure  requirements  associated  with  the  movement  amongst  or  hierarchy  associated  with  Level  1,  Level  2  and  Level  3  fair  value
measurements. This guidance is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019.
The  Company’s  adoption  of  this  standard  on  January  1,  2020,  did  not  have  a  material  impact  on  its  financial  statements  and  related
disclosures.

In  June  2018,  the  FASB  issued ASU  2018-07,  “Improvements  to  Nonemployee  Share-Based  Payment  Accounting”,  which  simplifies  the
accounting  for  share-based  payments  granted  to  nonemployees  for  goods  and  services.  Under  the ASU,  most  of  the  guidance  on  such
payments  to  nonemployees  would  be  aligned  with  the  requirements  for  share-based  payments  granted  to  employees.  The  changes  take
effect for public companies for fiscal years starting after December 15, 2018, including interim periods within that fiscal year. For all other
entities, the amendments are effective for fiscal years beginning after December 15, 2019, and interim periods within fiscal years beginning
after December 15, 2020. Early adoption is permitted, but no earlier than an entity’s adoption date of Topic 606. The Company adopted
ASU No. 2018-07 as of January 1, 2019. The adoption of this update did not have a material impact on the Company’s financial statements.

In  July  2017,  the  FASB  issued ASU  2017-11,  “Earnings  Per  Share  (Topic  260),  Distinguishing  Liabilities  from  Equity  (Topic  480)  and
Derivatives and Hedging (Topic 815): I. Accounting for Certain Financial Instruments with Down Round Features; II. Replacement of the
Indefinite Deferral for Mandatorily Redeemable Financial Instruments of Certain Nonpublic Entities and Certain Mandatorily Redeemable
Noncontrolling  Interests  with  a  Scope  Exception”.  Part  I  of  this  update  addresses  the  complexity  of  accounting  for  certain  financial
instruments with down round features. Down round features are features of certain equity-linked instruments (or embedded features) that
result in the strike price being reduced on the basis of the pricing of future equity offerings. Current accounting guidance creates cost and
complexity for entities that issue financial instruments (such as warrants and convertible instruments) with down round features that require
fair value measurement of the entire instrument or conversion option. Part II of this update addresses the difficulty of navigating Topic 480,
Distinguishing  Liabilities  from  Equity,  because  of  the  existence  of  extensive  pending  content  in  the  FASB  Accounting  Standards
Codification. This pending content is the result of the indefinite deferral of accounting requirements about mandatorily redeemable financial
instruments  of  certain  nonpublic  entities  and  certain  mandatorily  redeemable  noncontrolling  interests.  The  amendments  in  Part  II  of  this
update do not have an accounting effect. This ASU

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is  effective  for  fiscal  years,  and  interim  periods  within  those  years,  beginning  after  December  15,  2018.  The  adoption  of  this ASU  on
January 1, 2019, did not have a material impact on the Company’s financial statements.

In  February  2016,  the  FASB  issued  ASU  2016-02,  “Leases  (Topic  842)”  in  order  to  increase  transparency  and  comparability  among
organizations by, among other provisions, recognizing lease assets and lease liabilities on the balance sheet for those leases classified as
operating  leases  under  previous  GAAP.  For  public  companies, ASU  2016-02  is  effective  for  fiscal  years  beginning  after  December  15,
2018  (including  interim  periods  within  those  periods),  using  a  modified  retrospective  approach  and  early  adoption  is  permitted.  In
transition, entities may also elect a package of practical expedients that must be applied in its entirety to all leases commencing before the
adoption date, unless the lease is modified, and permits entities to not reassess (a) the existence of a lease, (b) lease classification or (c)
determination of initial direct costs, as of the adoption date, which effectively allows entities to carry forward accounting conclusions under
previous U.S. GAAP. In July 2018, the FASB issued ASU 2018-11, Leases (Topic 842): Targeted Improvements, which provides entities
an optional transition method to apply the guidance under Topic 842 as of the adoption date, rather than as of the earliest period presented.
The Company adopted Topic 842 on January 1, 2019, using the optional transition method to apply the new guidance as of January 1, 2019,
rather than as of the earliest period presented, and elected the package of practical expedients described above. Based on the analysis, on
January 1, 2019, the Company recorded right of use assets of approximately $1.2 million, lease liability of approximately $2.0 million and
eliminated deferred rent of approximately $0.7 million.

Recent Accounting Pronouncements

In  June  2016,  the  FASB  issued ASU  2016-13, “Financial  Instruments  –  Credit  Losses”.  The ASU  sets  forth  a  “current  expected  credit
loss” (CECL) model which requires the Company to measure all expected credit losses for financial instruments held at the reporting date
based on historical experience, current conditions, and reasonable supportable forecasts. This replaces the existing incurred loss model and
is applicable to the measurement of credit losses on financial assets measured at amortized cost and applies to some off-balance sheet credit
exposures. This ASU is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years,
with early adoption permitted. Recently, the FASB issued the final ASU to delay adoption for smaller reporting companies to calendar year
2023. The Company is currently assessing the impact of the adoption of this ASU on its financial statements.

Note 3 - License, Clinical Trial and Sponsored Research Agreements

Research and Development Expenses – All Licenses

For the years ended December 31, 2020 and 2019, the Company recorded the following expense in research and development for licenses
acquired:

($ in thousands)
City of Hope National Medical Center

CD123
CS1
IL13Rα2
Spacer
PSCA
HER2

CSL Behring (Calimmune)
UCLA
Fred Hutchinson Cancer Research Center - CD20
Nationwide Children's Hospital - C134
SIRION Biotech LentiBOOSTTM
Fortress PIK Dividend
Total

F-12

For the year ended December 31, 

2020

2019

$

$

334
200
333
333
200
500
170
—
300
—
117
7,577
10,064

$

$

250
200
—
—
200
—
200
300
—
200
—
4,923
6,273

    
    
Table of Contents

License Agreements

City of Hope

CD123 License (MB-102)

In  February  2017,  the  Company  entered  into  an Amended  and  Restated  Exclusive  License Agreement  with  the  City  of  Hope  National
Medical  Center  (“COH”)  to  acquire  intellectual  property  rights  pertaining  to  CD123  -specific  chimeric  antigen  receptor  (“CAR”)
engineered  T  cell  (“CAR  T”)  technology.  Pursuant  to  this  agreement,  the  Company  and  COH  acknowledged  that  an  upfront  fee  was
previously  paid.  In  addition,  COH  is  eligible  to  receive  an  annual  maintenance  fee  of  $25,000  and  milestone  payments  totaling  $14.5
million upon the achievement of certain milestones. Royalty payments in the mid-single digits are due on net sales of licensed products.

For the year ended December 31, 2020, the Company expensed a non-refundable milestone payment of $0.3 million in connection with our
public underwritten offerings. For the year ended December 31, 2019, the Company expensed a non-refundable milestone payment of $0.3
million upon the twelfth patient dosed in a Phase 1 clinical study of the CD123-directed CAR T.

CS1 License (MB-104)

In  May  2017,  the  Company  entered  into  an  exclusive  license  agreement  with  the  COH  for  the  use  of  CS1-specific  CAR  T  technology.
Pursuant to this agreement, the Company paid an upfront fee of $0.6 million and pays an annual maintenance fee of $50,000. Additional
payments are due for the achievement of ten development milestones totaling $14.9 million, and royalty payments in the mid-single digits
are due on net sales of licensed products.

For the year ended December 31, 2020, the Company expensed a non-refundable milestone payment of $0.2 million upon issuance of the
first  patent  related  to  the  CS1  CAR  T  technology.  For  the  year  ended  December  31,  2019,  the  Company  expensed  a  non-refundable
milestone payment of $0.2 million upon the first patient dosed in a Phase 1 clinical study of the CS1-directed CAR T.

IL13Rα2 License (MB-101)

In  February  2017,  the  Company  entered  into  an Amended  and  Restated  Exclusive  License Agreement  with  COH  to  acquire  intellectual
property  rights  pertaining  to  IL13Rα2-specific  CAR  T  technology.  Pursuant  to  this  agreement,  payments  are  due  for  the  achievement
of eight development milestones totaling $14.5 million; additional payments are due upon the occurrence of certain one-time; events and
royalty payments as a percentage of revenue in the mid-single digits are due on net sales of licensed products.  

For the year ended, December 31, 2020, the Company expensed a non-refundable milestone payment of $0.3  million  in  connection  with
Mustang’s public underwritten offerings. There was no expense recorded for the year ended December 31, 2019.

IV/ICV License

On  February  17,  2017,  the  Company  entered  into  an  exclusive  license  agreement  (the  “IV/ICV  Agreement”)  with  COH  to  acquire
intellectual property rights in patent applications related to the intraventricular and intracerebroventricular methods of delivering T cells that
express CARs. Pursuant to the IV/ICV Agreement, we paid COH an upfront fee of $0.1 million in March 2017. COH is eligible to receive
up to approximately $0.1 million in milestone payments upon the achievement of a certain milestone as well as an annual maintenance fee.
Royalty payments in the low-single digits are due on net sales of licensed products and services. During the years ended December 31, 2020
and 2019, there was no expense in connection with the IV/ICV Agreement.

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Spacer License

In  February  2017,  the  Company  entered  into  an Amended  and  Restated  Exclusive  License Agreement  with  COH  to  acquire  intellectual
property rights pertaining to Spacer patent rights. Pursuant to this agreement, payments are due upon the occurrence of certain one-time
events and royalty payments as a percentage of revenue in the low single digits are due on net sales of licensed products.

For  the  year  ended  December  31,  2020,  the  Company  expensed  a  non-refundable  milestone  payment  of  $0.3  million  in  connection  with
Mustang’s public underwritten offerings. There was no expense recorded for the year ended December 31, 2019.

PSCA License (MB-105)

In May 2017, the Company entered into an exclusive license agreement with COH for the use of prostate stem cell antigen (“PSCA”) CAR
T  technology  to  be  used  in  the  treatment  of  prostate  cancer,  pancreatic  cancer  and  other  solid  tumors.  Pursuant  to  this  agreement,  the
Company  paid  an  upfront  fee  of  $0.3  million  and  pays  an  annual  maintenance  fee  of  $50,000.  Additional  payments  are  due  for    the
achievement  of ten development milestones totaling $14.9 million, and royalty payments in the mid-single digits are due on net sales of
licensed products.

For the year ended December 31, 2020, the Company expensed a non-refundable milestone payment of $0.2 million upon issuance of the
first  patent  related  to  the  PCSA  CAR  T  technology.  For  the  year  ended  December  31,  2019,  the  Company  expensed  a  non-refundable
milestone payment of $0.2 million upon the first patient dosed in a Phase 1 clinical study of PSCA.

HER2 License (MB-103)

On May 31, 2017, the Company entered into an exclusive license agreement with the COH for the use of human epidermal growth factor
receptor  2  (“HER2”)  CAR  T  technology,  which  will  initially  be  applied  in  the  treatment  of  glioblastoma  multiforme.  Pursuant  to  this
agreement,  the  Company  paid  an  upfront  fee  of  $0.6  million  and  pays  an  annual  maintenance  fee  of  $50,000  (which  began  in  2019).
Additional payments are due for the achievement of ten development milestones totaling $14.9 million, and royalty payments in the mid-
single digits are due on net sales of licensed products.

For the year ended, December 31, 2020, the Company expensed a non-refundable milestone payment of $0.5 million in connection with the
12th patient treated in the Phase 1 clinical study of HER2 CAR T technology at COH. There was no expense recorded for the year ended
December 31, 2019.

CSL Behring (Calimmune) License

On August  23,  2019,  the  Company  entered  into  a  non-exclusive  license  agreement  with  CSL  Behring  (Calimmune,  Inc.)  (“Calimmune
License”) for the rights to the CytegrityTM stable producer cell line for the production of viral vector for our lentiviral gene therapy program
for the treatment of XSCID (MB-107 and MB-207). We previously licensed the XSCID gene therapy program from St. Jude Children’s
Research Hospital, Inc. (“St. Jude”) in August 2018. Pursuant to the terms of the Calimmune License, the Company paid an upfront fee of
$0.2 million. CSL Behring is eligible to receive additional payments totaling $1.2 million upon the achievement of three development and
commercialization milestones. Royalty payments in the low-single digits are due on net sales of licensed products.

For  the  year  ended  December  31,  2020,  the  Company  expensed  a  non-refundable  milestone  payment  of  $0.2  million  due  upon  the  first
anniversary  of  the  Calimmune  license.  For  the  year  ended  December  31,  2019,  upon  the  execution  of  the  Calimmune  License,  the
Company recorded research and development expense of $0.2 million.

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University of California Los Angeles License

On  March  17,  2017,  the  Company  entered  into  an  exclusive  license  agreement  with  the  Regents  of  the  University  of  California  at  Los
Angeles (“UCLA License”) to acquire intellectual property rights in patent applications related to engineered anti-prostate stem cell antigen
antibodies for cancer targeting and detection. In September 2019, COH commenced its Phase 1 clinical trial resulting in the achievement of
a  development  milestone,  and  the  Company  recorded  an  expense  of  $0.3  million  in  the  Statements  of  Operations  for  the  year  ended
December 31, 2019. There was no expense recorded for the year ended December 31, 2020.

Fred Hutchinson Cancer Research Center - CD20 License (MB-106)

On July 3, 2017, the Company entered into an exclusive, worldwide licensing agreement with Fred Hutchinson Cancer Research Center
(“Fred  Hutch”)  for  the  use  of  a  CAR  T  therapy  related  to  autologous  T  cells  engineered  to  express  a  CD20-specific  chimeric  antigen
receptor  (“CD20  Technology  License”).  Pursuant  to  the  CD20  Technology  License,  the  Company  paid  Fred  Hutch  an  upfront  fee  of
$0.3 million and will owe an annual maintenance fee of $50,000 on each anniversary of the license until the achievement by the Company
of  regulatory  approval  of  a  licensed  product  using  CD20  Technology.  Additional  payments  are  due  for  the  achievement
of  eleven  development  milestones  totaling  $39.1  million  and  royalty  payments  in  the  mid-single  digits  are  due  on  net  sales  of  licensed
products.

For the year ended December 31, 2020, the Company expensed a non-refundable milestone payment of $0.3 million in connection with the
twelfth patient treated in the Phase 1 clinical study of CD20 CAR T technology at Fred Hutch. There was no expense recorded for the year
ended December 31, 2019.

Nationwide Children’s Hospital – C134 License (MB-108)

In February 2019, the Company announced that it partnered and entered into an exclusive worldwide license agreement with Nationwide
Children’s Hospital (“Nationwide”) to develop their C134 oncolytic virus (MB-108) for the treatment of glioblastoma multiforme (“GBM”).
We intend to combine MB-108 with MB-101 (IL13Rα2-specific CAR T) to potentially enhance efficacy in treating GBM. The Company
paid $0.2  million  in  consideration  for  the  license  to  exclusive,  worldwide  rights  to  develop  and  commercialize  products  that  incorporate
data, know-how and/or patents related to MB-108 that were developed at Nationwide. Additional payments are due to Nationwide upon
achievement of development and commercialization milestones totaling $152.8 million. Royalty payments in the low-single digits are due
on net sales of licensed products.

For  the  year  ended  December  31,  2019,  the  Company  recorded  an  expense  of  $0.2  million  in  connection  with  this  license.  There  was no
expense recorded for the year ended December 31, 2020.

SIRION Biotech GmbH - LentiBOOSTTM

In  October  2020,  we  announced  a  licensing  agreement  with  SIRION  Biotech  (“SIRION”)  for  the  rights  to  SIRION’s  LentiBOOSTTM
technology for the development of MB-207, our lentiviral gene therapy for the treatment of previously transplanted XSCID patients (the
“SIRION  Technology  License”).  Pursuant  to  the  SIRION  Technology  License,  the  Company  paid  SIRION  a  one-time  upfront  fee
o f $0.1  million  (€0.1  million).  In  addition, five  future  development  milestone  payments  totaling  up  to  approximately $5.6  million
(€4.7 million) in the aggregate are due upon achievement of certain milestones. Additional milestone payments totaling up to $4.1 million
(€3.5  million)  in  the  aggregate  are  due  in  connection  with  the  achievement  of three  commercial  milestones  and  low-  to  mid-single  digit
royalties are due on aggregate cumulative worldwide net sales of licensed products.

For the year ended December 31, 2020, the Company expensed an up-front payment of $0.1  million.  There  was no  expense  recorded  for
the year ended December 31, 2019.

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St. Jude Children’s Research Hospital License (MB-107 and MB-207)

On August 2, 2018, the Company entered into an exclusive worldwide license agreement with St. Jude for the development of a first-in-
class ex vivo lentiviral gene therapy for the treatment of X-linked severe combined immunodeficiency (“XSCID”). The Company paid $1.0
million in consideration for the exclusive license in addition to an annual maintenance fee of $0.1 million (which began in 2019). St. Jude is
eligible to receive payments totaling $13.5 million upon the achievement of five development and commercialization milestones. Royalty
payments in the mid-single digits are due on net sales of licensed products. During the years ended December 31, 2020 and 2019, there
were no expenses recorded in connection with this license.

Harvard College License

On November 20, 2017, the Company entered into an exclusive, worldwide license agreement with the President and Fellows of Harvard
College (the “Harvard Agreement”) for the use of gene editing, via the use of CRISPR/Cas9, to be used in enhancing the efficacy of CAR T
cell  therapies  for  solid  tumor  indications  and  to  generate  universal  off  the  shelf  CAR  T  cell  therapies  for  both  liquid  and  solid  tumor
indications.  Pursuant  to  the  Harvard  Agreement,  we  paid  Harvard  College  an  upfront  fee  of  $0.3  million  and  will  owe  an  annual
maintenance fee of $25,000 and $50,000 for calendar years 2018 and 2019, respectively, and $100,000 for each subsequent calendar year
during the term of the agreement. Additional payments are due for the achievement of  seven development milestones totaling $16.7 million
and royalty payments in the low-single digits are due on the net sales of licensed products. During the years ended December 31, 2020 and
2019, we recorded no expense in connection with the Harvard Agreement. The Harvard Agreement was terminated in January 2020.

Research and Development Expenses - Sponsored Research and Clinical Trial Agreements

For the year ended December 31, 2020 and 2019, the Company recorded the following expense in research and development for sponsored
research and clinical trial agreements:

($ in thousands)
City of Hope National Medical Center

CD123
IL13Rα2
CS1
HER2
PSCA
Manufacturing

Fred Hutchinson Cancer Research Center - CD20
St. Jude Children's Research Hospital - XSCID
Beth Israel Deaconess Medical Center - CRISPR
Total

City of Hope

Sponsored Research Agreement

For the year ended December 31, 
2019
2020

500
433
530
885
1,519
204
—
1,804
1,842
—
7,717

2,000
1,202
876
—
—
—
457
762
777
69
6,143

In March 2015, the Company entered into a Sponsored Research Agreement (“SRA”) with COH in which the Company funded continued
research in the amount of $2.0 million per year, payable in four equal installments, through the first quarter of 2020. The research covered
under this arrangement is for IL13Rα2, CD123 and the Spacer technology. For the years ended December 31, 2020 and 2019, the Company
recorded $0.5 million and $2.0 million, respectively, in research and development expenses in the Statements of Operations pursuant to the
terms of this agreement.

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CD123 (MB-102) Clinical Research Support Agreement

In February 2017, the Company entered into a Clinical Research Support Agreement for CD123 (the “CD123 CRA”). Pursuant to the terms
of the CD123 CRA the Company made an upfront payment of $19,450 and will contribute an additional $97,490 per patient in connection
with the on-going investigator-initiated study. Further, the Company agreed to fund approximately $ 0.2 million over three years pertaining
to  the  clinical  development  of  CD123.  For  the  years  ended  December  31,  2020  and  2019,  the  Company  recorded  $0.4  million  and  $1.2
million, respectively, in research and development expenses in the Statements of Operations pursuant to the terms of this agreement.

IL13Rα2 (MB-101) Clinical Research Support Agreements

In  February  2017,  the  Company  entered  into  a  clinical  research  support  agreement  for  IL13Rα2  (the  “IL13Rα2  CRA”).  Pursuant  to  the
terms of the IL13Rα2 CRA the Company made an upfront payment of approximately $9,300 and will contribute an additional $0.1 million
related  to  patient  costs  in  connection  with  the  on-going  investigator-initiated  study.  Further,  the  Company  agreed  to  fund  approximately
$0.2  million  over three years  pertaining  to  the  clinical  development  of  IL13Rα2.  For  the  years  ended  December  31,  2020  and  2019,  the
Company  recorded  $0.5  million  and  $0.9  million,  respectively,  in  research  and  development  expenses  under  the  IL13Rα2  CRA  in  the
Statements of Operations pursuant to the terms of this agreement.

In October 2020, the Company entered into a Clinical Research Support Agreement for the IL13Rα2-directed CAR T program for adult
patients with leptomeningeal glioblastoma, ependymoma or medulloblastoma (the “IL13Rα2 Leptomeningeal CRA”). Pursuant to the terms
of the IL13Rα2 Leptomeningeal CRA, the Company made an upfront payment of approximately $29,000 and will contribute an additional
$0.1 million per patient in connection with the on-going investigator-initiated study. Further, the Company agreed to fund approximately
$0.2 million annually pertaining to the clinical development of the IL13Rα2-directed CAR T therapy.

CS1 (MB-104) Clinical Research Support Agreement

In  June  2020,  the  Company  entered  into  a  clinical  research  support  agreement  with  COH  in  connection  with  an  Investigator-sponsored
study conducted under an Institutional Review Board-approved, investigator-initiated protocol entitled: “Phase I Study to Evaluate Cellular
Immunotherapy  Using  Memory-Enriched  T  Cells  Lentivirally  Transduced  to  Express  a  CS1-Targeting,  Hinge-Optimized,  41BB-
Costimulatory Chimeric Antigen Receptor and a Truncated EGFR Following Lymphodepleting Chemotherapy in Adult Patients with CS1+
Multiple Myeloma.” The CAR T being studied under this protocol has been designated as MB-104. Under the terms of the agreement we
will reimburse COH for costs associated with this trial not to exceed $2.4 million. The agreement will expire upon the delivery of a final
study  report  or  earlier.  During  the  year  ended  December  31,  2020,  the  Company  recorded  $0.9  million  in  research  and  development
expenses in the Statements of Operations pursuant to the terms of this agreement.

HER2 (MB-103) Clinical Research Support Agreement

In  September  2020,  the  Company  entered  into  a  clinical  research  support  agreement  with  COH  in  connection  with  an  Investigator-
sponsored  study  conducted  under  an  Institutional  Review  Board-approved,  investigator-initiated  protocol  entitled:  “Phase  I  Study  of
Cellular Immunotherapy using Memory-Enriched T Cells Lentivirally Transduced to Express a HER2-Specific, Hinge-Optimized, 41BB-
Costimulatory  Chimeric  Receptor  and  a  Truncated  CD19  for  Patients  with  Recurrent/Refractory  Malignant  Glioma.”  The  CAR  T  being
studied under this protocol has been designated as MB-103. Under the terms of the agreement the Company will pay COH $29,375 upon
execution  and  will  reimburse  COH  for  costs  associated  with  this  trial  not  to  exceed  $3.0  million.  The  agreement  will  expire  upon  the
delivery  of  a  final  study  report  or  earlier.  For  the  year  ended  December  31,  2020,  the  Company  recorded  $1.5  million  in  research  and
development expenses in the Statements of Operations pursuant to the terms of this agreement.

PSCA (MB-105) Clinical Research Support Agreement

In October 2020, the Company entered into a clinical research support agreement with COH in connection with an Investigator-sponsored
study  conducted  under  an  Institutional  Review  Board-approved,  investigator-initiated  protocol  entitled:  “A  Phase  1b  study  to  evaluate
PSCA-specific chimeric antigen receptor (CAR)-T cells for patients with metastatic

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castration resistant prostate cancer.” The CAR T being studied under this protocol has been designated as MB-105. Under the terms of the
agreement the Company will pay COH $33,000 upon execution and will reimburse COH for costs associated with this trial not to exceed
$2.3 million.  The agreement will expire upon the delivery of a final study report or earlier. For the year ended December 31, 2020, the
Company  recorded  $0.2  million  in  research  and  development  expenses  in  the  Statements  of  Operations  pursuant  to  the  terms  of  this
agreement.

Sponsored Research Agreement - Manufacturing

On January 3, 2018, the Company entered into an SRA with COH to optimize and develop CAR T cell processing procedures. Pursuant to
the  SRA,  the  Company  will  fund  continued  research  in  the  amount  of  $0.9  million  for  the  program,  which  has  an  initial  term  of two
(2)  years.  For  the  year  ended  December  31,  2020  and  2019,  the  Company  recorded nil  and  $0.5  million,  respectively,  in  research  and
development expenses in the Statements of Operations pursuant to the terms of this agreement.

Fred Hutchinson Cancer Research Center

CD20 Clinical Trial Agreement

On July 3, 2017, in conjunction with the CD20 Technology License from Fred Hutch, we entered into an investigator-initiated clinical trial
agreement (“CD20 CTA”) to provide partial funding for a Phase 1/2 clinical trial at Fred Hutch evaluating the safety and efficacy of the
CD20 Technology in patients with relapsed or refractory B-cell non-Hodgkin lymphomas. In connection with the CD20 CTA, the Company
agreed  to  fund  up  to  $5.3  million  of  costs  associated  with  the  clinical  trial,  which  commenced  during  the  fourth  quarter  of  2017.  In
November 2020, the CD20 CTA was amended to include additional funding of approximately $ 0.8 million for the treatment of five patients
with  chronic  lymphocytic  leukemia.  For  the  years  ended  December  31,  2020  and  2019,  the  Company  recorded  $1.8  million  and  $0.6
million, respectively, in research and development expenses in the Statements of Operations pursuant to the terms of this agreement.

Sponsored Research Agreement - Manufacturing

On  March  17,  2018,  the  Company  entered  into  an  SRA  with  Fred  Hutch  related  to  developing  and  optimizing  processes  and  systems
associated with CD20 cell processing. Pursuant to the SRA, the Company funded research in the amount of $0.6 million during the term of
the SRA, which expired in March 2019. For the years ended December 31, 2020 and 2019, the Company recorded expense of nil and $0.2
million, respectively, in research and development expenses in the Statements of Operations pursuant to the terms of this agreement.

XSCID (MB-107) Data Transfer Agreement with St. Jude Children’s Research Hospital

In  June  2020,  the  Company  entered  into  a  Data  Transfer Agreement  with  St.  Jude  under  which  we  will  reimburse  St.  Jude  for  costs
associated with St. Jude’s clinical trial for the treatment of infants with XSCID.  Pursuant to the terms of this agreement we paid an upfront
fee of $1.1 million in July 2020, and will continue to reimburse St. Jude for costs incurred in connection with this clinical trial. For the years
ended December 31, 2020 and 2019, the Company recorded $1.8 million and nil, respectively, in research and development expenses in the
Statements of Operations pursuant to the terms of this agreement.

XSCID (MB-107) Non-Interventional Services Agreement with Children’s CGMP

In December 2019, Mustang entered into a Non-Interventional Services Agreement with Children's CGMP, LLC ("Children’s"), an affiliate
of St. Jude Children's Research Hospital, pursuant to which Children’s provides lentiviral vector for non-clinical XSCID research purposes,
as well as related advisory services. We agreed to fund approximately $0.8 million upon execution of the agreement, which was recorded in
research  and  development  expenses  for  the  year  ended  December  31,  2019,  in  the  Company's  Statements  of  Operations  pursuant  to  the
terms of this agreement.

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CRISPR Sponsored Research Agreement with Beth Israel Deaconess Medical Center, Inc.

On  November  28,  2017,  the  Company  entered  into  an  SRA  with  Beth  Israel  Deaconess  Medical  Center  Inc.  (“BIDMC”)  to  perform
research relating to gene editing, via the use of CRISPR/Cas9, to be used in enhancing the efficacy of CAR T cell therapies for solid tumor
indications and to generate universal off-the-shelf CAR T cell therapies for both liquid and solid tumor indications. The Company agreed to
fund  approximately  $0.8  million  over  a three-year  period.  For  the  year  ended  December  31,  2020  and  2019,  the  Company  recorded
approximately nil and $0.1  million,  respectively,  in  research  and  development  expenses  in  the  Statements  of  Operations  pursuant  to  the
terms of this agreement.

In January 2019, the Company terminated the SRA with BIDMC due to the departure of key personnel from BIDMC.

Note 4 - Related Party Agreements

Founders Agreement and Management Services Agreement with Fortress

Effective March 13, 2015, the Company entered a Founders Agreement with Fortress, which was amended and restated on May 17, 2016,
and again on July 26, 2016 (the “Mustang Founders Agreement”). The Mustang Founders Agreement provides that, in exchange for the time
and capital expended in the formation of Mustang and the identification of specific assets the acquisition of which result in the formation of
a  viable  emerging  growth  life  science  company,  Fortress  loaned  $2.0  million,  representing  the  up-front  fee  required  to  acquire  the
Company’s license agreement with COH. The Mustang Founders Agreement has a term of  15 years, which upon expiration automatically
renews for successive one-year periods unless terminated by Fortress and the Company or a Change in Control (as defined in the Mustang
Founders Agreement) occurs. Concurrently with the second amendment on July 26, 2016, to the Mustang Founders Agreement, Fortress
entered into an Exchange Agreement whereby Fortress exchanged its 7.25 million Class B Common shares for 7.0 million common shares
and 250,000 Class A Preferred shares. Class A Preferred Stock is identical to common stock other than as to voting rights, conversion rights
and the PIK Dividend right (as described below). Each share of Class A Preferred Stock will be entitled to vote the number of votes that is
equal to one and one-tenth (1.1)  times  a  fraction,  the  numerator  of  which  is  the  sum  of  (A)  the  shares  of  outstanding  Mustang  common
stock  and  (B)  the  whole  shares  of  Mustang  common  stock  into  which  the  shares  of  outstanding  Class A  Common  Stock  and  Class A
Preferred Stock are convertible and the denominator of which is the number of shares of outstanding Class A Preferred Stock. Thus, the
Class A  Preferred  Stock  will  at  all  times  constitute  a  voting  majority.  Each  share  of  Class A  Preferred  Stock  is  convertible,  at  Fortress’
option,  into one  fully  paid  and  nonassessable  share  of  Mustang  common  stock,  subject  to  certain  adjustments. As  holders  of  Class A
Preferred  Stock,  Fortress  will  receive  on  each  January  1  (each  a  “PIK  Dividend  Payment  Date”)  until  the  date  all  outstanding  Class A
Preferred Stock is converted into common stock or redeemed (and the purchase price is paid in full), pro rata per share dividends paid in
additional fully paid and nonassessable shares of common stock (“PIK Dividends”) such that the aggregate number of shares of common
stock  issued  pursuant  to  such  PIK  Dividend  is  equal  to  two  and  one-half  percent  (2.5%)  of  Mustang’s  fully-diluted  outstanding
capitalization on the date that is one (1) business day prior to any PIK Dividend Payment Date.

As additional consideration under the Mustang Founders Agreement, Mustang will also: (i) pay an equity fee in shares of common stock,
payable within five (5) business days of the closing of any equity or debt financing for Mustang that occurs after the effective date of the
Mustang Founders Agreement and ending on the date when Fortress no longer has majority voting control in the Company’s voting equity,
equal to two and one-half (2.5%) of the gross amount of any such equity or debt financing; and (ii) pay a cash fee equal to four and one-
half percent (4.5%) of the Company’s annual net sales, payable on an annual basis, within ninety (90) days of the end of each calendar year.
In the event of a Change in Control, the Company will pay a one-time change in control fee equal to five (5x) times the product of (A) net
sales for the twelve (12) months immediately preceding the change in control and (B) four and one-half percent (4.5%) (see Note 9).

Effective  as  of  March  13,  2015,  the  Company  entered  into  a  Management  Services Agreement  (the  “MSA”)  with  Fortress,  pursuant  to
which Fortress renders advisory and consulting services to the Company. The MSA has an initial term of  five years  and  is  automatically
renewed for successive five-year terms unless terminated in accordance with its provisions. Services provided under the MSA may include,
without limitation, (i) advice and assistance concerning any and all aspects of the Company’s operations, clinical trials, financial planning
and  strategic  transactions  and  financings  and  (ii)  conducting  relations  on  behalf  of  the  Company  with  accountants,  attorneys,  financial
advisors  and  other  professionals  (collectively,  the  “Services”).  The  Company  is  obligated  to  utilize  clinical  research  services,  medical
education, communication and

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marketing  services  and  investor  relations/public  relation  services  of  companies  or  individuals  designated  by  Fortress,  provided  those
services are offered at market prices. However, the Company is not obligated to take or act upon any advice rendered from Fortress and
Fortress shall not be liable for any of its actions or inactions based upon their advice. Fortress and its affiliates, including all members of the
Company’s Board of Directors, have been contractually exempt from fiduciary duties to the Company relating to corporate opportunities. In
consideration  for  the  Services,  the  Company  will  pay  Fortress  an  annual  consulting  fee  of  $0.5  million  (the  “Annual  Consulting  Fee”),
payable in advance in equal quarterly installments on the first business day of each calendar quarter in each year, provided, however, that
such Annual Consulting Fee shall be increased to $1.0 million for each calendar year in which the Company has net assets in excess  of
$100 million at the beginning of the calendar year. For the years ended December 31, 2020 and 2019, the Company recorded expense of
$0.5 million and $0.5 million, respectively, related to this agreement.

For  the  year  ended  December  31,  2020,  the  Company  issued 342,773  shares  of  common  stock  and  recorded 101,632  shares  issuable  to
Fortress,  which  equaled 2.5%  of  the  gross  proceeds  of  $59.8  million  from  the  sale  of  shares  of  common  stock  under  Mustang’s At-the-
Market Offering. The Company recorded an expense of approximately $1.5 million in general and administrative expenses related to these
shares for the year ended December 31, 2020.

For the year ended December 31, 2020, the Company issued 286,390 shares of common stock to Fortress, which equaled 2.5% of the gross
proceeds of $37.2 million from the sale of shares of common stock, before deducting underwriting discounts and commissions and offering
expenses under Mustang’s Public Offering. The Company recorded an expense of approximately $0.9 million in general and administrative
expenses related to these shares for the year ended December 31, 2020.

Under the terms of the Second Amended and Restated Founders Agreement, which became effective July 22, 2016, Fortress will receive a
grant  of  shares  of  our  common  stock  equal  to  two  and  one-half  percent  (2.5%)  of  the  gross  amount  of  any  equity  or  debt  financing.  In
March  2019,  the  Company  issued 108,069  shares  of  common  stock  to  Fortress,  which  equaled 2.5%  of  the  gross  funded  amount  of  the
Horizon Notes. The Company recorded an expense of approximately $0.4 million in general and administrative expenses related to these
shares during the year ended December 31, 2019.

For the year ended December 31, 2019, the Company issued 87,656 shares of common stock to Fortress, which equaled 2.5% of the gross
proceeds of $22.5 million from the sale of shares of common stock under Mustang’s At-the-Market Offering. The Company recorded an
expense of approximately $0.5 million in general and administrative expenses related to these shares during the year ended December 31,
2019.

For the year ended December 31, 2019, the Company issued 197,656 shares of common stock to Fortress, which equaled 2.5% of the gross
proceeds of $31.6 million from the sale of shares of common stock, before deducting underwriting discounts and commissions and offering
expenses under Mustang’s Public Offering. The Company recorded an expense of approximately $0.8 million in general and administrative
expenses related to these shares during the year ended December 31, 2019.

Payables and Accrued Expenses Related Party

In the normal course of business Fortress pays for certain expenses on behalf of the Company. Such expenses are recorded as Payables and
accrued expenses - related party and are reimbursed to Fortress in the normal course of business.

Director Compensation

Dr. Rosenwald

Pursuant to the terms of the Director Compensation Plan, Dr. Rosenwald will receive a cash fee of $50,000 per year paid quarterly and an
annual stock award of the greater of (i) a number of shares of common stock having a fair market value on the grant date of $50,000  or
(ii) 10,000 shares of common stock, which shares shall vest and become non-forfeitable on the third anniversary of the grant date, subject to
continued service on the Board on such date. For the year ended December 31, 2020, the Company recognized $113,000 in expense in its
Statements  of  Operations  related  to  the  director  compensation,  including  approximately  $63,000  in  expense  related  to  equity  incentive
grants of 50,000 restricted shares. For the year ended December 31, 2019, the Company recognized $102,000 in expense in its Statements
of Operations

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related  to  the  director  compensation,  including  approximately  $52,000  in  expense  related  to  equity  incentive  grants  of 34,000  restricted
shares.

Mr. Weiss - Advisory Agreement with Caribe BioAdvisors, LLC

The Board of the Company by unanimous written consent approved and authorized the execution of an advisory agreement dated January 1,
2017 (the “Advisory Agreement”), with Caribe BioAdvisors, LLC (the “Advisor”), owned by Michael S. Weiss, the Chairman of the Board,
to provide the board advisory services of Mr. Weiss as Chairman of the Board. Pursuant to the Advisory Agreement, the Advisor will be
paid an annual cash fee of $60,000, paid quarterly and an annual stock award of the greater of (i) a number of shares of common stock
having a fair market value on the grant date of $50,000  or  (ii) 10,000 shares of common stock, which shares shall vest and become non-
forfeitable on the third anniversary of the grant date, subject to continued service on the Board on such date. For the year ended December
31,  2020,  the  Company  recognized  $122,000  in  expense  in  its  Statements  of  Operations  related  to  the  advisory  agreement,  including
approximately $62,000 in expense related to equity incentive grants of 50,000 restricted shares. For the year ended December 31, 2019, the
Company  recognized  $105,000  in  expense  in  its  Statements  of  Operations  related  to  the  advisory  agreement,  including  approximately
$45,000 in expense related to equity incentive grants of 34,000 restricted shares.

Note 5 - Property and Equipment

Mustang’s property and equipment consisted of the following:

($ in thousands)
Computer equipment
Furniture and fixtures
Machinery and equipment
Leasehold improvements
Construction in process
Total property and equipment
Less: accumulated depreciation
Property and equipment, net

     Estimated Useful      December 31,       December 31, 

Life (in years)
3
5
5
9
N/A

2020

2019

$

$

68
181
5,748
5,099
499
11,595
(3,567)
8,028

$

$

53
145
4,594
3,877
1,157
9,826
(1,890)
7,936

Mustang’s  depreciation  expense  for  the  years  ended  December  2020  and  2019  was  approximately  $1.7  million  and  $1.3  million,
respectively, and was recorded in research and development expense in the Statements of Operations.

Note 6 - Accounts Payable and Accrued Expenses

At December 31, 2020 and 2019, accounts payable and accrued expenses consisted of the following:

($ in thousands)
Accounts payable
Research and development
Accrued compensation
Other
Total accounts payable and accrued expenses

F-21

December 31, 
2020

December 31, 
2019

$

$

3,518
2,862
2,009
358
8,747

$

$

1,877
1,760
1,496
535
5,668

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
    
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Note 7 - Commitments and Contingencies

Leases

On  October  27,  2017,  the  Company  entered  into  a  lease  agreement  with  WCS  -  377  Plantation  Street,  Inc.,  a  Massachusetts  nonprofit
corporation. Pursuant to the terms of the lease agreement, we agreed to lease 27,043 square feet from the landlord, located at 377 Plantation
Street in Worcester, MA (the “Facility”), through November 2026, subject to additional extensions at the Company’s option. Base rent, net
of abatements of $0.6 million over the lease term, totals approximately $3.6 million, on a triple-net basis.

The terms of the lease also require that we post an initial security deposit of $0.8 million, in the form of $0.5 million letter of credit and
$0.3 million in cash, which increased to $1.3 million ($1.0 million letter of credit, $0.3 million in cash) on November 1, 2019. After the
fifth lease year, the letter of credit obligation is subject to reduction.

The Facility began operations for the production of personalized CAR T and gene therapies in 2018.

The Company leases office space and copiers under agreements classified as operating leases that expire on various dates through 2026.
The Company’s lease liabilities result from the lease of its Facility in Massachusetts, which expires in 2026, and its copier, which expires in
2021. Such leases do not require any contingent rental payments, impose any financial restrictions, or contain any residual value guarantees.
Certain of the Company’s leases include renewal options and escalation clauses; renewal options have not been included in the calculation
of the lease liabilities and right of use assets as the Company is not reasonably certain to exercise the options. The Company does not act as
a lessor or have any leases classified as financing leases. At December 31, 2020, the Company had operating lease liabilities of $2.2 million
and right of use assets of $1.1 million, which were included in the Balance Sheet.

The following summarizes quantitative information about the Company’s operating leases:

($ in thousands)
Lease cost

Operating lease cost
Variable lease cost

Total

($ in thousands)
Operating cash flows from operating leases
Weighted-average remaining lease term – operating leases
Weighted-average discount rate – operating leases

Maturities of our operating leases, excluding short-term leases, are as follows:

($ in thousands)
Year ended December 31, 2021
Year ended December 31, 2022
Year ended December 31, 2023
Year ended December 31, 2024
Year ended December 31, 2025
Thereafter
Total
Less present value discount
Operating lease liabilities

F-22

For the Year Ended

December 31, 
2020

December 31, 
2019

  $

  $

330   $
470
800   $

312
684
996

For the Year Ended

December 31, 
2020

December 31, 
2019

  $

  $

76
5.8
9.0 %

148
4.3
9.0 %

$

$

467
476
489
503
516
439
2,890
(662)
2,228

    
    
    
    
    
    
 
    
      
 
    
 
 
 
 
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Note 8 - Notes Payable

On March 29, 2019 (the “Closing Date”), the Company entered into a $20.0 million Loan Agreement with Horizon, the proceeds of which
provided the Company with additional working capital to continue development of its gene and cell therapies. In accordance with the Loan
Agreement, $15.0 million of the $20.0 million loan was funded on the Closing Date, with the remaining $5.0 million fundable upon the
Company achieving certain predetermined milestones.

Each  advance  under  the  Horizon  Loan Agreement  will  mature 42 months  from  the  first  day  of  the  month  following  the  funding  of  the
advance. The first three advances will mature on October 1, 2022 (the “Loan Maturity Date”). Each advance accrues interest at a per annum
rate of interest equal to 9.00% plus the amount by which the one-month LIBOR Rate, as reported in the Wall Street Journal, exceeds 2.50%.
The Loan Agreement provides for interest-only payments commencing May 1, 2019, through and including October 1, 2020. The interest-
only  period  may  be  extended  to April  1,  2021,  if  the  Company  satisfies  the  Interest  Only  Extension  Milestone  (as  defined  in  the  Loan
Agreement). Thereafter, commencing May 1, 2021, amortization payments will be payable monthly in  eighteen  installments  of  principal
and interest. At its option, upon ten business days’ prior written notice to Horizon, the Company may prepay all or any portion greater than
or equal to $500,000 of each of the outstanding advances by paying the entire principal balance (or portion thereof) and all accrued and
unpaid interest, subject to a prepayment charge of 4.0% of the then outstanding principal balance of each advance if such advance is prepaid
on or before the Loan Amortization Date (as defined in the Loan Agreement),  3% if such advance is prepaid after the Loan Amortization
Date applicable to such Loan, but on or prior to twelve months following the Loan Amortization Date, and 2% thereafter. In addition, a
final  payment  equal  to  $250,000  for  each  advance  (i.e.,  $750,000  in  aggregate  with  respect  to  the  initial  $15.0  million)  is  due  on  the
maturity date or other date of payment in full. Amounts outstanding during an event of default shall be payable on demand and shall accrue
interest at an additional rate of 5.0% per annum of the past due amount outstanding.

Each  advance  of  the  loan  is  secured  by  a  lien  on  substantially  all  of  the  assets  of  the  Company,  other  than  Intellectual  Property  and
Excluded Collateral (in each case as defined in the Loan Agreement), and contains customary covenants and representations, including a
liquidity covenant, financial reporting covenant and limitations on dividends, indebtedness, collateral, investments, distributions, transfers,
mergers or acquisitions, taxes, corporate changes, deposit accounts, and subsidiaries.

The events of default under the Loan Agreement include, among other things, without limitation, and subject to customary grace periods,
(1)  the  Company's  failure  to  make  any  payments  of  principal  or  interest  under  the  Loan  Agreement,  promissory  notes  or  other  loan
documents, (2) the Company’s breach or default in the performance of any covenant under the Loan Agreement, (3) the occurrence of a
material  adverse  change,  (4)  the  Company  making  a  false  or  misleading  representation  or  warranty  in  any  material  respect,  (5)  the
Company’s insolvency or bankruptcy, (6) certain attachments or judgments on the Company’s assets, (7) the occurrence of any material
default under certain agreements or obligations of the Company involving indebtedness in excess of $250,000, or (8) failing to maintain
certain minimum monthly cash balances which range from approximately $8 to $13 million over the term of the loan ($13.0 million as of
December 31, 2020). If an event of default occurs, Horizon is entitled to take enforcement action, including acceleration of amounts due
under the Loan Agreement.

The Loan Agreement also contains warrant coverage of 5% of the total amount funded. Four warrants (the “Warrants”) were issued by the
Company to Horizon to purchase a combined 288,184 shares of the Company’s common stock with an exercise price of $3.47  and  a  fair
value of $0.9 million. The Warrants are exercisable for ten years from the date of issuance. Horizon may exercise the Warrants either by (a)
cash  or  check  or  (b)  through  a  net  issuance  conversion.  The  shares  of  the  Company’s  common  stock  will,  upon  request  by  Horizon,  be
registered and freely tradable following a period of six months after issuance.

The Company paid Horizon an initial commitment fee of $0.2 million and reimbursed Horizon for $30,000 of legal fees in connection with
the  Loan  Agreement.  The  Company  incurred  approximately  $1.2  million  of  legal  and  other  direct  costs  in  connection  with  the  Loan
Agreement.

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All fees, warrants and costs paid to Horizon and all direct costs incurred by the Company are recognized as a debt discount to the funded
loans and are amortized to interest expense using the effective interest method over the term of the Loan Agreement.

Amortization of the debt discount associated with the funded loans was approximately $2.3  million  and  $0.7  million  for  the  years  ended
December 31, 2020 and 2019, respectively, and was included in interest expense in the Statements of Operations.

On  September  30,  2020,  the  Company  repaid  the  amount  outstanding  under  the  Horizon  Notes  in  full,  which  was  comprised  of  $15.0
million face value of the outstanding notes, $0.1 million in accrued and unpaid interest, a $0.8 million final payment fee and prepayment
penalties of $0.6  million.  For  the  year  ended  December  31,  2020,  the  Company  recorded  interest  expense  of  approximately  $2.1  million
related to the early repayment of the Horizon Notes.

($ in thousands)
Horizon Notes (1)(2)
Discount on notes payable

Total notes payable
Less: current portion

Long-term notes payable

December 31, 
2020

     December 31,      
2019

     Interest Rate     

Maturity

  $

  $

  $

—   $
—
—   $
—
—   $

15,750
(2,321)
13,429
(1,250)
12,179

9.00 % October - 2022

(1) Balance includes $0.75 million final payment fee
(2)

Interest rate is 9.00% plus one-month LIBOR Rate in excess of 2.5%

Note 9 - Stockholders’ Equity

Common Stock

The  Company,  in  accordance  with  its  certificate  of  incorporation,  as  amended  in  November  2020,  which  was  retroactively  applied,  is
authorized  to  issue  (i) 125,000,000  common  shares  with  a  par  value  of  $0.0001  per  share,  of  which 1,000,000  shares  are  designated  as
Class A  Common  Stock  and  the  remainder  are  undesignated  Common  Stock,  and  (ii)  2,000,000  shares  of  Preferred  Stock, 250,000  of
which are designated as Class A Preferred Stock and the remainder are undesignated Preferred Stock (see below Stock Issuances to Fortress
and Note 4).

In connection with the Company’s formation, Fortress subscribed for 7,000,000 shares of the Class B Common Stock and 2,000,000 shares
of the Company’s Common Stock, pursuant to the Founders Agreement. Fortress paid the par value of $ 900 in 2016. The fair value of the
Company’s common shares approximated par value as no licenses had been transferred at that time. Dividends, if and when declared, are to
be distributed pro-rata to the Class A, B and Common Stockholders.

The  holders  of  Common  Stock  are  entitled  to one  vote  per  share  of  Common  Stock  held.  The  holders  of  Class A  Common  Stock  are
entitled to the number of votes equal to the number of whole shares of Common Stock into which the shares of Class A Common Stock
held by such holder are convertible and for a period of ten years from its issuance, the holders of the Class A Common Stock have the right
to appoint one member of the board of directors of Mustang; to date, the holders of Class A Common Stock have not yet appointed such
director.

The Class B Common Stockholders are entitled, for each share of Class B Common Stock held, to a number of votes equal to 1.1 times a
fraction, the numerator of which is the sum of (A) the shares of outstanding Common Stock and (B) the whole shares of Common Stock
into which the shares of outstanding Class A Common Stock and the Class B Common Stock are convertible and the denominator of which
is the number of shares of outstanding Class B common shares.

In April  2019,  COH  converted 137,608  shares  of  the  Company’s  Class A  common  stock  to 137,608  shares  of  the  Company’s  common
stock.  In  November  2019,  COH  converted 17,007  shares  of  the  Company’s  Class A  common  stock  to 17,007  shares  of  the  Company’s
common stock for a total of 154,615 Class A common stock converted into the Company’s common stock in 2019.

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On August 16, 2019, the Company’s Board adopted resolutions of the Board to ratify, approve and recommend stockholder approval of an
amendment to the Company’s Amended and Restated Certificate of Incorporation, as amended, to revise Article IV, Section A thereof in
order  to  effect  an  increase  in  the  authorized  number  of  shares  of  the  Company’s  common  stock,  par  value  $0.0001,  from 50,000,000  to
85,000,000 (the “Amendment”). On August 16, 2019, the Company received approval of the Amendment by written consent in lieu of a
meeting from the holders of a majority of issued and outstanding shares of the Company’s common and preferred stock. The increase in
authorized shares to 85,000,000 became effective on September 30, 2019.

On November 11, 2020, the Company’s Board adopted resolutions of the Board to ratify, approve and recommend stockholder approval of
an amendment to the Company’s Amended and Restated Certificate of Incorporation, as amended, to revise Article IV, Section A thereof in
order  to  effect  an  increase  in  the  authorized  number  of  shares  of  the  Company’s  common  stock,  par  value  $0.0001,  from 85,000,000  to
125,000,000 (the “Amendment”). On November 11, 2020, the Company received approval of the Amendment by written consent in lieu of
a meeting from the holders of a majority of issued and outstanding shares of the Company’s common and preferred stock. The increase in
authorized shares to 125,000,000 became effective on December 4, 2020.

At-the-Market Offering of Common Stock

On July 13, 2018, the Company filed a shelf registration statement No. 333-226175 on Form S-3 , as amended on July 20, 2018 (the “2018
S-3”),  which  was  declared  effective  in August  2018.  Under  the  2018  S-3,  the  Company  may  sell  up  to  a  total  of  $ 75.0  million  of  its
securities. In connection with the 2018 S-3, the Company entered into an At-the-Market Issuance Sales Agreement (the “ATM Agreement”)
with B. Riley Securities, Inc. (formerly B. Riley FBR, Inc.), Cantor Fitzgerald & Co., National Securities Corporation, and Oppenheimer &
Co. Inc. (each an “Agent” and collectively, the “Agents”), relating to the sale of shares of common stock. Under the ATM Agreement, the
Company  pays  the Agents  a  commission  rate  of  up  to 3.0%  of  the  gross  proceeds  from  the  sale  of  any  shares  of  common  stock.  On
December 31, 2020, the ATM Agreement was amended to add H.C. Wainwright & Co., LLC as an Agent.

During the year ended December 31, 2020, the Company issued approximately 17.6 million shares of common stock at an average price of
$3.40  per  share  for  gross  proceeds  of  $59.8  million  under  the  ATM  Agreement.  In  connection  with  these  sales,  the  Company  paid
aggregate fees of approximately $1.1 million for net proceeds of approximately $58.7 million.

During the year ended December 31, 2019, the Company issued approximately 3.5 million shares of common stock at an average price of
$6.42  per  share  for  gross  proceeds  of  $22.5  million  under  the  ATM  Agreement.  In  connection  with  these  sales,  the  Company  paid
aggregate fees of approximately $0.5 million for net proceeds of approximately $22.0 million.

Public Offering of Common Stock

On  June  11,  2020,  we  entered  into  an  underwriting  agreement  (the  “Underwriting  Agreement”)  with  Cantor  Fitzgerald  &  Co.,  as
representative  of  the  underwriters  named  therein  (each,  an  “Underwriter”  and  collectively  with  Cantor  Fitzgerald  &  Co.,  the
“Underwriters”). In connection with the Underwriting Agreement, we issued 10,769,231 shares of common stock (plus a 30-day option to
purchase up to an additional 1,615,384 shares of common stock, of which 686,373 were exercised) at a price of $3.25 per share for gross
proceeds of approximately $37.2 million, before deducting underwriting discounts and commissions and offering expenses. In connection
with the public offering, we paid aggregate fees of approximately $2.4 million for net proceeds of approximately $34.8 million. The shares
were sold under our S-3 registrations filed with the Securities and Exchange Commission. The offering closed on June 15, 2020, and the
over-allotment closed on June 25, 2020.

On April 30, 2019, the Company announced the pricing of an underwritten public offering, whereby we sold 6,875,000 shares of common
stock, (plus a 30-day option to purchase up to an additional 1,031,250 shares of common stock, which was fully exercised) at a price of
$4.00 per share for gross proceeds of approximately $31.6 million, before deducting underwriting discounts and commissions and offering
expenses.  In  connection  with  the  public  offering,  the  Company  paid  aggregate  fees  of  approximately  $2.1  million  for  net  proceeds  of
approximately $29.5 million. The shares were sold under the 2018 S-3, filed with the Securities and Exchange Commission. The offering
closed on May 2, 2019, and the over-allotment closing was on May 8, 2019.

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Registration Statements

On October 23, 2020, the Company filed a shelf registration statement No. 333-249657 on Form S-3 (the “2020 S-3”), which was declared
effective on December 4, 2020. Under the 2020 S-3, the Company may sell up to a total of $100.0 million of its securities. As of December
31, 2020, approximately $85.7 million of the 2020 S-3 remains available for sales of securities.

On August 16, 2019, the Company filed a shelf registration statement No. 333-233350 on Form S-3 (the “2019 S-3”), which was declared
effective on September 30, 2019. Under the 2019 S-3, the Company may sell up to a total of $75.0 million of its securities. As of December
31, 2020, the 2019 S-3 is no longer available for sales of securities.

Stock Issuances to Fortress

Under the terms of the Second Amended and Restated Founders Agreement, which became effective July 22, 2016, Fortress will receive a
grant of shares of our common stock equal to two and one-half percent (2.5%) of the gross amount of any equity or debt financing.

For  the  year  ended  December  31,  2020,  the  Company  issued 342,773  shares  of  common  stock  and  recorded 101,632  shares  issuable  to
Fortress,  which  equaled 2.5%  of  the  gross  proceeds  of  $59.8  million  from  the  sale  of  shares  of  common  stock  under  Mustang’s At-the-
Market Offering.

For the year ended December 31, 2020, the Company issued 286,390 shares of common stock to Fortress, which equaled 2.5% of the gross
proceeds of $37.2 million from the sale of shares of common stock, before deducting underwriting discounts and commissions and offering
expenses under Mustang’s Public Offering.

For the year ended December 31, 2019, the Company issued 108,069 shares of common stock to Fortress, which equaled 2.5% of the gross
funded amount of the Horizon Notes.

For the year ended December 31, 2019, the Company issued 87,656 shares of common stock to Fortress, which equaled 2.5% of the gross
proceeds of $22.5 million from the sale of shares of common stock under Mustang’s At-the-Market Offering.

For the year ended December 31, 2019, the Company issued 197,656 shares of common stock to Fortress, which equaled 2.5% of the gross
proceeds of $31.6 million from the sale of shares of common stock under Mustang’s Public Offering.

Equity Incentive Plan

The Company has in effect the 2016 Incentive Plan (the “Incentive Plan”). The Incentive Plan was adopted in 2016 by our stockholders and
the  compensation  committee  of  the  Company’s  board  of  directors  and  is  authorized  to  grant  stock-based  awards  to  directors,  officers,
employees and consultants. The plan initially authorized grants to issue up to 2,000,000 shares of authorized but unissued common stock
and expires 10 years from adoption and limits the term of each option to no more than 10 years from the date of grant.

In  June  2018,  the  Company’s  stockholders  approved  an  amendment  to  the  Incentive  Plan  to  increase  the  number  of  authorized  shares
issuable  by 3,000,000  shares,  for  a  total  of 5,000,000  shares.  Total  shares  available  for  the  issuance  of  stock-based  awards  under  the
Incentive Plan was 1,180,085 shares at December 31, 2020.

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Stock Options

The following table summarizes stock option activities for the year ended December 31, 2020 and 2019:

Outstanding at December 31, 2018
Options granted
Outstanding at December 31, 2019
Options forfeited
Outstanding at December 31, 2020
Options vested and exercisable at December 31, 2020

Weighted Average
Exercise Price

     Weighted Average

Remaining
Contractual Life (in
years)

5.73  
—  
5.73  
5.73  
5.73  
5.73  

8.31
—
7.31
—
6.31
6.31

Stock Options
1,241,675

$
—  

1,241,675
(100,000)
1,141,675
784,902

$

As of December 31, 2020, the Company had unrecognized stock-based compensation expense related to options of $0.1 million, which is
expected to be recognized over a weighted average period of approximately 0.8 year . Effective on January 1, 2017, the Company elected to
account for forfeited awards as they occur as permitted by ASU 2016-09. Ultimately, the actual expenses recognized over the vesting period
will  be  for  those  shares  that  vested.  Prior  to  making  this  election,  the  Company  estimated  a  forfeiture  rate  for  awards  at 0%,  as  the
Company did not have a significant history of forfeitures.

Restricted Stock Awards

Certain  employees  and  directors  have  been  awarded  restricted  stock.  The  restricted  stock  vesting  consists  of  milestone  and  time-based
vesting. The following table summarizes restricted stock award activities for the year ended December 31, 2020 and 2019:

Nonvested at December 31, 2018
Granted
Vested
Forfeited
Nonvested at December 31, 2019
Granted
Vested
Nonvested at December 31, 2020

Number of Shares
502,636
119,060
—
(322,636)
299,060
83,055
(80,001)
302,114

     Weighted Average
Grant Date Fair
Value

$

$

$

5.73
3.83
—
5.14
5.66
3.08
5.73
4.93

As  of  December  31,  2020,  the  Company  had  unrecognized  stock-based  compensation  expense  related  to  restricted  stock  of  $0.3  million,
which is expected to be recognized over a weighted average period of approximately 2.2 years.

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Restricted Stock Units

The following table summarizes restricted stock units’ activities for the year ended December 31, 2020 and 2019:

Nonvested at December 31, 2018
Granted
Forfeited
Vested
Nonvested at December 31, 2019
Granted
Forfeited
Vested
Nonvested at December 31, 2020

Number of Units
1,032,084
625,000
(344,750)
(199,917)
1,112,417
973,000
(205,125)
(411,733)
1,468,559

     Weighted Average
Grant Date Fair
Value

$

$

$

7.77
3.01
7.67
7.81
5.11
2.95
4.24
4.87
3.87

As  of  December  31,  2020,  the  Company  had  unrecognized  stock-based  compensation  expense  related  to  restricted  stock  units  of
approximately $2.6 million, which is expected to be recognized over a weighted average period of approximately 1.9 years.

The following table summarizes stock-based compensation expense for the years ended December 31, 2020 and 2019 (in thousands).

General and administrative
Research and development
Total stock-based compensation expense

Stock Warrants

For the year ended December 31, 

2020

2019

$

$

1,550
1,437
2,987

$

$

1,790
874
2,664

In connection with the Company’s offering of shares of common stock in a private placement, each investor received a warrant equal to
25% of the common shares purchased in connection with the offering. Further, National Securities Corporation received Placement Agent
Warrants.

A summary of warrant activities for years ended December 31, 2020 and 2019, is presented below:

Outstanding as of December 31, 2018
Granted
Exercised
Outstanding as of December 31, 2019
Cashless exercised
Outstanding as of December 31, 2020

Weighted Average
Exercise Price

     Weighted Average

Remaining
Contractual Life (in
years)

$

$

$

8.32  
3.47  
—  
8.20  
—  
8.21  

3.10
9.25
—
2.40
—
1.39

Warrants
5,210,698
288,184
(93,213)
5,405,669
(2,999)
5,402,670

Upon the exercise of warrants, the Company will issue new shares of Common Stock.

Employee Stock Purchase Plan

In connection with our Employee Stock Purchase Plan (“ESPP”), eligible employees of Mustang and Fortress can purchase the Company’s
Common Stock at the end of a predetermined offering period at 85% of the lower of the fair market value at the beginning or end of the
offering period.

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As of December 31, 2020, 140,856 shares have been purchased and 259,144 shares are available for future sale under the Company’s ESPP.

Note 10 - Income Taxes

The Company has accumulated net losses since inception and has not recorded an income tax provision or benefit during the years ended
December 31, 2020 and 2019.

A reconciliation of the statutory U.S. federal rate to the Company’s effective tax rate is as follows:

Statutory federal income tax rate
State taxes, net of federal tax benefit
Non-deductible items
Credits
Federal tax rate change
State tax rate change
Other
Change in valuation allowance
Income taxes provision (benefit)

For the year ended December 31,

2020

2019

21 %  
16 %  
(1)%  
4 %  
— %  
1 %  
— %  
(41)%  
—  

21 %
15 %
— %
3 %
— %
4 %
(2)%
(41)%
—

The components of the net deferred tax asset as of December 31, 2020 and 2019 are the following ($ in thousands):

Deferred tax assets:

Net operating loss carryovers
Stock compensation and other
Change in fair value of warrant liabilities
Amortization of license
Lease liability
Accruals and reserves
Startup costs
Debt issuance costs
Tax credits

Total deferred tax assets

Less: valuation allowance

Net deferred tax assets

Deferred tax liabilities:
Right of use asset

Total deferred tax assets, net

For the year ended December 31, 

2020

2019

$

$

$

45,090
2,444
59
12,804
825
504
7
—
5,743
67,476
(67,073)
403

$

$

27,446
2,037
57
9,454
746
519
7
21
2,746
43,033
(42,608)
425

(403)

— $

(425)
—

The  Company  has  determined,  based  upon  available  evidence,  that  it  is  more  likely  than  not  that  the  net  deferred  tax  asset  will  not  be
realized and, accordingly, has provided a full valuation allowance against its net deferred tax assets as of December 31, 2020 and 2019. A
valuation allowance of approximately $67.1 million and $42.6 million, respectively, was recorded for the years ended December 31, 2020
and 2019.

As of December 31, 2020, the Company had federal and state net operating loss carryforwards of approximately $133.3 million and $263.6
million, respectively. Approximately $109.6 million and $43,000 of the federal and state net operating loss carryforwards, respectively, can
be carried forward indefinitely. The remaining $ 23.7 million and $263.5 million of federal and state net operating loss carryforwards will
begin to expire, if not utilized, by 2035 and 2029, respectively. As of December 31, 2020, the Company had federal and state income tax
credits of approximately $4.8 million and $1.2

F-29

 
    
    
 
 
 
 
 
 
 
 
 
 
    
    
 
    
  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Table of Contents

million, respectively, which will begin to expire in 2033. Under the provisions of Section 382 of the Internal Revenue Code, a corporation
that undergoes an “ownership change”, as defined therein, is subject to limitations on its use of pre-change NOLs and income tax credits
carryforwards  to  offset  future  tax  liabilities.  The  Company  is  currently  evaluating  the  impact  of  Section  382  on  its  tax  attributes.  The
Company  has  recorded  a  full  valuation  allowance  on  all  of  its  deferred  tax  assets  as  it  believes  that  it  is  more  likely  than  not  that  the
deferred tax assets will not be realized regardless of whether an “ownership change” has occurred.

There are no significant items determined to be unrecognized tax benefits taken or expected to be taken in a tax return, in accordance with
ASC  740  “Income  Taxes”  (“ASC  740”),  which  clarifies  the  accounting  for  uncertainty  in  income  taxes  recognized  in  the  financial
statements, that have been recorded on the Company’s financial statements for the period ended December 31, 2020. The Company does
not anticipate a material change to unrecognized tax benefits in the next twelve months.

Additionally, ASC  740  provides  guidance  on  the  recognition  of  interest  and  penalties  related  to  income  taxes.  There  were no  interest  or
penalties related to income taxes that have been accrued or recognized as of and for the period ended December 31, 2020.

The  federal  and  state  tax  returns  for  the  years  ended  December  31,  2017,  2018,  and  2019  are  currently  open  for  examination  under  the
applicable federal and state income tax statutes of limitations.

In response to the COVID-19 pandemic, the Coronavirus Aid, Relief and Economic Security Act ("CARES Act") was signed into law on
March  27,  2020.  The  CARES Act,  among  other  things,  includes  tax  provisions  relating  to  refundable  payroll  tax  credits,  deferment  of
employer's  social  security  payments,  net  operating  loss  utilization  and  carryback  periods  and  modifications  to  the  net  interest  deduction
limitations. The CARES Act did not have a material impact on the Company’s income tax provision for 2020. The Company will continue
to evaluate the impact of the CARES Act on its financial position, results of operations and cash flows.

On  December  27,  2020,  the  President  of  the  United  States  signed  the  Consolidated  Appropriations  Act,  2021  (“Consolidated
Appropriations Act”) into law. The Consolidated Appropriations Act is intended to enhance and expand certain provisions of the CARES
Act, allows for the deductions of expenses related to the Payroll Protection Program funds received by companies, and provides an update
to  meals  and  entertainment  expensing  for  2021.  The  Consolidated Appropriations Act  did  not  have  a  material  impact  to  the  Company’s
income tax provision for 2020.

F-30

Table of Contents

Pursuant to the requirements of Section 12 of the Securities Exchange Act of 1934, the registrant has duly caused this Form 10-K to be
signed on its behalf by the undersigned, thereunto duly authorized.

SIGNATURES

Mustang Bio, Inc.

By: /s/ Manuel Litchman

Name: Manuel Litchman
Title: President and Chief Executive Officer

  March 24, 2021

POWER OF ATTORNEY

We, the undersigned directors and/or executive officers of Mustang Bio, Inc., hereby severally constitute and appoint Manuel Litchman,
acting singly, his or her true and lawful attorney-in-fact and agent, with full power of substitution and resubstitution, for him or her in any
and all capacities, to sign this Form 10-K and to file the same, with all exhibits thereto and other documents in connection therewith, with
the Securities and Exchange Commission, granting unto said attorney-in-fact and agent full power and authority to do and perform each and
every act and thing necessary or appropriate to be done in connection therewith, as fully for all intents and purposes as he or she might or
could do in person, hereby approving, ratifying and confirming all that said attorney-in-fact and agent, or his substitute, may lawfully do or
cause to be done by virtue hereof.

Pursuant to the requirements of the Securities Exchange Act of 1934, this Form 10-K has been signed below by the following persons on
behalf of the registrant and in the capacities and on the dates indicated.

Signature

Title

Date

/s/ Michael S. Weiss
Michael S. Weiss

/s/ Manuel Litchman
Manuel Litchman, M.D.

/s/ Lindsay A. Rosenwald
Lindsay A. Rosenwald, M.D.

/s/ Neil Herskowitz
Neil Herskowitz

/s/ Adam Chill
Adam Chill

/s/ Michael Zelefsky
Michael Zelefsky, M.D.

/s/ Brian Achenbach
Brian Achenbach

Executive Chairman of the Board

March 24, 2021

President and Chief Executive Officer

March 24, 2021

Director

Director

Director

Director

March 24, 2021

March 24, 2021

March 24, 2021

March 24, 2021

Senior Vice President of Finance & Corporate Controller

March 24, 2021

67

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
   
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
DESCRIPTION OF THE REGISTRANT’S SECURITIES
REGISTERED PURSUANT TO SECTION 12 OF THE 
SECURITIES EXCHANGE ACT OF 1934

DESCRIPTION OF CAPITAL STOCK

EXHIBIT 4.3

When used herein, the terms “Company,” “we,” “our,” and “us” refer to Mustang Bio, Inc.

Capital Stock

The  Company  is  authorized  to  issue  125,000,000  shares  of  common  stock  with  a  par  value  of  $0.0001  per  share,  of  which
1,000,000 shares are designated as Class A common stock and 2,000,000 of preferred stock at $0.0001 par value of which 250,000 are
designated as Class A preferred stock.

The holders of common stock are entitled to one vote per share of common stock held.

The undesignated preferred stock may be issued from time to time in one or more series. The Board of Directors is authorized
to  determine  or  alter  the  dividend  rights,  dividend  rate,  conversion  rights,  voting  rights,  rights  and  terms  of  redemption  (including
sinking fund provisions, if any), the redemption price or prices, the liquidation preferences and other designations, powers, preferences
and  relative,  participating,  optional  or  other  special  rights,  if  any,  and  the  qualifications,  limitations  and  restrictions  granted  to  or
imposed upon any wholly unissued series of preferred stock, and to fix the number of shares of any series of preferred stock (but not
below the number of shares of any such series then outstanding).

Class A Common Stock

The holders of Class A common stock are entitled to the number of votes equal to the number of whole shares of common
stock into which the shares of Class A common shares held by such holder are convertible. For a period of ten years from issuance, the
holders of the Class A common stock have the right to appoint one member of the board of directors of Mustang. To date, the holders
of Class A common stock have not yet appointed such director.

Class A Preferred Stock

The Class A Preferred Stock is identical to undesignated common stock other than as to voting rights, conversion rights, and

the PIK dividend right.

The holders of the outstanding shares of Class A Preferred Stock receive on each January 1 (each a “PIK Dividend Payment
Date”)  after  the  original  issuance  date  of  the  Class  A  Preferred  Stock  until  the  date  all  outstanding  Class  A  Preferred  Stock  is
converted into common stock or redeemed (and the purchase price is paid in full), pro rata per share dividends paid in additional fully
paid and non-assessable shares of common stock such that the aggregate number of shares of common stock issued pursuant to such
PIK dividend is equal to 2.5% of the Corporation’s fully-diluted outstanding capitalization on the date that is one business day prior to
any  PIK  Dividend  Payment  Date  (“PIK  Record  Date”).  In  the  event  the  Class A  Preferred  Stock  converts  into  common  stock,  the
holders shall receive all PIK dividends accrued through the date of such conversion. No dividend or other distribution shall be paid, or
declared and set apart for payment (other than dividends payable solely in capital stock on the capital stock) on the shares of common
stock until all PIK dividends on the Class A Preferred Stock shall have been paid or declared and set apart for payment. All dividends
are non-cumulative.

On  any  matter  presented  to  the  stockholders  for  their  action  or  consideration  at  any  meeting  of  stockholders  (or  by  written
consent of stockholders in lieu of meeting), each holder of outstanding shares of Class A Preferred Stock shall be entitled to cast for
each share of Class A Preferred Stock held by such holder as of the record date for determining stockholders entitled to vote on such
matter,  the  number  of  votes  that  is  equal  to  one  and  one-tenth  (1.1)  times  a  fraction,  the  numerator  of  which  is  the  sum  of  (A)  the
number of shares of outstanding common stock and (B) the whole shares of common stock in to which the shares of outstanding Class
A Common Stock and the Class A Preferred Stock are convertible,

1

and the denominator of which is number of shares of outstanding Class A Preferred Stock. Thus, the Class A Preferred Stock will at all
times constitute a voting majority.

Each share of Class A Preferred Stock is convertible, at the option of the holder, into one fully paid and nonassessable share of
common  stock,  subject  to  certain  adjustments.  If  the  Company,  at  any  time  effects  a  subdivision  or  combination  of  the  outstanding
common stock (by any stock split, stock dividend, recapitalization, reverse stock split or otherwise), the applicable conversion ratio in
effect  immediately  before  that  subdivision  is  proportionately  decreased  or  increased,  as  applicable,  so  that  the  number  of  shares  of
common  stock  issuable  on  conversion  of  each  share  of  Class A  Preferred  Stock  shall  be  increased  or  decreased,  as  applicable,  in
proportion  to  such  increase  or  decrease  in  the  aggregate  number  of  shares  of  common  stock  outstanding.  Additionally,  if  any
reorganization, recapitalization, reclassification, consolidation or merger involving the Company occurs in which the common stock
(but not the Class A Preferred Stock) is converted into or exchanged for securities, cash or other property, then each share of Class A
Preferred Stock becomes convertible into the kind and amount of securities, cash or other property which a holder of the number of
shares of common stock of the Company issuable upon conversion of one share of the Class A Preferred Stock immediately prior to
such  reorganization,  recapitalization,  reclassification,  consolidation  or  merger  would  have  been  entitled  to  receive  pursuant  to  such
transaction.

Additional Features

Other features of our capital stock include:

●

●

●

●

●

Dividend Rights. The holders of outstanding shares of our common stock, including Class A common stock, are entitled
to  receive  dividends  out  of  funds  legally  available  at  the  times  and  in  the  amounts  that  our  board  of  directors  may
determine. All dividends are non-cumulative.

Voting Rights . The holders of our common stock are entitled to one vote for each share of common stock held on all
matters submitted to a vote of the stockholders, including the election of directors. Our certificate of incorporation and
bylaws do not provide for cumulative voting rights.

No  Preemptive  or  Similar  Rights .  The  holders  of  our  common  stock  have  no  preemptive,  conversion,  or  subscription
rights, and there are no redemption or sinking fund provisions applicable to our common stock.

Right to Receive Liquidation Distributions. Upon our liquidation, dissolution, or winding-up, the assets legally available
for distribution to our stockholders would be distributable ratably among the holders of our common stock, including
Class A common stock, outstanding at that time after payment of other claims of creditors, if any.

Fully Paid and Non-Assessable. All of the outstanding shares of our common stock, including Class A common stock,
and the Class A Preferred Stock are duly issued, fully paid and non-assessable.

DESCRIPTION OF WARRANTS

The terms relating to any warrants to purchase shares of our common stock or preferred stock, in one or more series together

with other securities or separately, will include some or all of the following:

●

●

●

●

the title of the warrants;

the aggregate number of warrants offered;

the  designation,  number  and  terms  of  the  shares  of  common  stock  purchasable  upon  exercise  of  the  warrants  and
procedures by which those numbers may be adjusted;

the exercise price of the warrants;

2

●

●

●

●

●

●

●

●

the dates or periods during which the warrants are exercisable;

the designation and terms of any securities with which the warrants are issued;

if the warrants are issued as a unit with another security, the date on and after which the warrants and the other security
will be separately transferable;

if the exercise price is not payable in U.S. dollars, the foreign currency, currency unit or composite currency in which the
exercise price is denominated;

any minimum or maximum amount of warrants that may be exercised at any one time;

any terms relating to the modification of the warrants;

any terms, procedures and limitations relating to the transferability, exchange or exercise of the warrants; and

any other specific terms of the warrants.

3

DESCRIPTION OF DEBT SECURITIES

We  may  offer  debt  securities  which  may  be  senior,  subordinated  or  junior  subordinated  and  may  be  convertible.  Unless
otherwise specified, our debt securities will be issued in one or more series under an indenture to be entered into between us and a
trustee.  The  debt  securities  will  be  issued  under  an  indenture  to  be  entered  into  between  us  and  a  trustee.  The  terms  of  the  debt
securities will include those stated in the indenture and those made part of the indenture by reference to the Trust Indenture Act of
1939, as in effect on the date of the indenture. The indenture will be subject to and governed by the terms of the Trust Indenture Act of
1939.

The following description briefly sets forth certain general terms and provisions of the debt securities that we may offer.

Debt Securities

The aggregate principal amount of debt securities that may be issued under the indenture is unlimited. The debt securities may
be issued in one or more series as may be authorized from time to time pursuant to a supplemental indenture entered into between us
and the trustee or an order delivered by us to the trustee. Debt securities we offer will be subject to the following terms and conditions
of the series of debt securities being offered, to the extent applicable:

●

●

●

●

●

●

●

●

●

●

●

●

●

●

title and aggregate principal amount;

whether the debt securities will be senior, subordinated or junior subordinated;

applicable subordination provisions, if any;

provisions regarding whether the debt securities will be convertible or exchangeable into other securities or property of
the Company or any other person;

percentage or percentages of principal amount at which the debt securities will be issued;

maturity date(s);

interest rate(s) or the method for determining the interest rate(s);

whether interest on the debt securities will be payable in cash or additional debt securities of the same series;

dates on which interest will accrue or the method for determining dates on which interest will accrue and dates on which
interest will be payable;

whether the amount of payment of principal of, premium, if any, or interest on the debt securities may be determined
with reference to an index, formula or other method;

redemption,  repurchase  or  early  repayment  provisions,  including  our  obligation  or  right  to  redeem,  purchase  or  repay
debt securities under a sinking fund, amortization or analogous provision;

if other than the debt securities’ principal amount, the portion of the principal amount of the debt securities that will be
payable upon declaration of acceleration of the maturity;

authorized denominations;

form;

4

●

●

●

●

●

●

●

●

●

●

●

●

●

●

●

●

●

●

●

●

amount  of  discount  or  premium,  if  any,  with  which  the  debt  securities  will  be  issued,  including  whether  the  debt
securities will be issued as “original issue discount” securities;

the place or places where the principal of, premium, if any, and interest on the debt securities will be payable;

where the debt securities may be presented for registration of transfer, exchange or conversion;

the place or places where notices and demands to or upon the Company in respect of the debt securities may be made;

whether the debt securities will be issued in whole or in part in the form of one or more global securities;

if the debt securities will be issued in whole or in part in the form of a book-entry security, the depository or its nominee
with  respect  to  the  debt  securities  and  the  circumstances  under  which  the  book-entry  security  may  be  registered  for
transfer or exchange or authenticated and delivered in the name of a person other than the depository or its nominee;

whether a temporary security is to be issued with respect to such series and whether any interest payable prior to the
issuance of definitive securities of the series will be credited to the account of the persons entitled thereto;

the  terms  upon  which  beneficial  interests  in  a  temporary  global  security  may  be  exchanged  in  whole  or  in  part  for
beneficial interests in a definitive global security or for individual definitive securities;

the guarantors, if any, of the debt securities, and the extent of the guarantees and any additions or changes to permit or
facilitate guarantees of such debt securities;

any covenants applicable to the particular debt securities being issued;

any  defaults  and  events  of  default  applicable  to  the  debt  securities,  including  the  remedies  available  in  connection
therewith;

currency, currencies or currency units in which the purchase price for, the principal of and any premium and any interest
on, such debt securities will be payable;

time period within which, the manner in which and the terms and conditions upon which the Company or the purchaser
of the debt securities can select the payment currency;

securities exchange(s) on which the debt securities will be listed, if any;

whether any underwriter(s) will act as market maker(s) for the debt securities;

extent to which a secondary market for the debt securities is expected to develop;

provisions relating to defeasance;

provisions relating to satisfaction and discharge of the indenture;

any restrictions or conditions on the transferability of the debt securities;

provisions relating to the modification of the indenture both with and without the consent of holders of debt securities
issued under the indenture;

5

any addition or change in the provisions related to compensation and reimbursement of the trustee;

provisions, if any, granting special rights to holders upon the occurrence of specified events;

whether the debt securities will be secured or unsecured, and, if secured, the terms upon which the debt securities will be
secured and any other additions or changes relating to such security; and

any other terms of the debt securities that are not inconsistent with the provisions of the Trust Indenture Act (but may
modify, amend, supplement or delete any of the terms of the indenture with respect to such series of debt securities).

●

●

●

●

General

One or more series of debt securities may be sold as “original issue discount” securities. These debt securities would be sold at
a substantial discount below their stated principal amount, bearing no interest or interest at a rate which at the time of issuance is below
market  rates.  One  or  more  series  of  debt  securities  may  be  variable  rate  debt  securities  that  may  be  exchanged  for  fixed  rate  debt
securities.

Debt securities may be issued where the amount of principal and/or interest payable is determined by reference to one or more
currency  exchange  rates,  commodity  prices,  equity  indices  or  other  factors.  Holders  of  such  debt  securities  may  receive  a  principal
amount or a payment of interest that is greater than or less than the amount of principal or interest otherwise payable on such dates,
depending upon the value of the applicable currencies, commodities, equity indices or other factors.

The term “debt securities” includes debt securities denominated in U.S. dollars or, if applicable, in any other freely transferable

currency or units based on or relating to foreign currencies.

We expect most debt securities to be issued in fully registered form without coupons and in denominations of $1,000 and any
integral  multiples  thereof.  Subject  to  applicable  limitations,  debt  securities  that  are  issued  in  registered  form  may  be  transferred  or
exchanged at the principal corporate trust office of the trustee, without the payment of any service charge, other than any tax or other
governmental charge payable in connection therewith.

Global Securities

The  debt  securities  of  a  series  may  be  issued  in  whole  or  in  part  in  the  form  of  one  or  more  global  securities  that  will  be
deposited with, or on behalf of, a depositary. Global securities will be issued in registered form and in either temporary or definitive
form. Unless and until it is exchanged in whole or in part for the individual debt securities, a global security may not be transferred
except as a whole by the depositary for such global security to a nominee of such depositary or by a nominee of such depositary to such
depositary or another nominee of such depositary or by such depositary or any such nominee to a successor of such depositary or a
nominee of such successor.

Governing Law

The indenture and the debt securities shall be construed in accordance with and governed by the laws of the State of New York.

DESCRIPTION OF UNITS

We  may  issue,  in  one  more  series,  units  comprised  of  shares  of  our  common  stock,  preferred  stock,  warrants  to  purchase
common stock or preferred stock, debt securities or any combination of those securities. Each unit will be issued so that the holder of
the unit is also the holder of each security included in the unit. Thus, the holder of a unit will have the rights and obligations of a holder
of each included security. The unit agreement under which a unit is issued may provide that the securities included in the unit may not
be held or transferred separately, at any time or at any time before a specified date.

6

 
We  may  evidence  units  by  unit  certificates  that  we  issue  under  a  separate  agreement.  We  may  issue  the  units  under  a  unit
agreement between us and one or more unit agents. If we elect to enter into a unit agreement with a unit agent, the unit agent will act
solely as our agent in connection with the units and will not assume any obligation or relationship of agency or trust for or with any
registered holders of units or beneficial owners of units.

The terms of the series of units that may be offered will include:

●

●

●

the  designation  and  terms  of  the  units  and  of  the  securities  comprising  the  units,  including  whether  and  under  what
circumstances those securities may be held or transferred separately;

any provisions of the governing unit agreement that differ from those described herein; and

any provisions for the issuance, payment, settlement, transfer or exchange of the units or of the securities comprising the
units.

The other provisions regarding our common stock, preferred stock, warrants and debt securities as described in this exhibit will

apply to each unit to the extent such unit consists of shares of our common stock, warrants and/or debt securities.

7

Exhibit 23.1

Consent of Independent Registered Public Accounting Firm

Mustang Bio, Inc.
New York, New York

We  hereby  consent  to  the  incorporation  by  reference  in  the  Registration  Statements  on  Form  S-3  (Nos.  333-226175,  333-233350  and  333-
249657) and Form S-8 (Nos. 333-221819) of Mustang Bio, Inc. of our report dated March 24, 2021 relating to the financial statements, which
appears in this Form 10-K.

/s/ BDO USA, LLP
Boston, Massachusetts
March 24, 2021

 
 
 
 
CERTIFICATION PURSUANT TO

SECTION 302 OF THE SARBANES-OXLEY ACT OF 2002

EXHIBIT 31.1

I, Manuel Litchman, M.D., President and Chief Executive Officer (Principal Executive Officer), certify that:

(1)

I have reviewed this Annual Report on Form 10-K for the year ended December 31, 2020 of Mustang Bio, Inc. (the registrant);

(2) Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make
the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered
by this report;

(3) Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects,

the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

(4) The registrant’s other certifying officer(s) and I are responsible for establishing and maintaining disclosure controls and procedures (as defined
in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and
15d-15(f)) for the registrant and have:

(a) designed  such  disclosure  controls  and  procedures,  or  caused  such  disclosure  controls  and  procedures  to  be  designed  under  our
supervision,  to  ensure  that  material  information  relating  to  the  registrant  is  made  known  to  us  by  others  within  those  entities,
particularly during the period in which this report is being prepared;

(b) designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under
our  supervision,  to  provide  reasonable  assurance  regarding  the  reliability  of  financial  reporting  and  the  preparation  of  financial
statements for external purposes in accordance with generally accepted accounting principles;

(c) evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about
the  effectiveness  of  the  disclosure  controls  and  procedures,  as  of  the  end  of  the  period  covered  by  this  report  based  on  such
evaluation; and

(d) disclosed  in  the  report  any  change  in  the  registrant’s  internal  control  over  financial  reporting  that  occurred  during  the  registrant’s
most  recent  fiscal  quarter  (the  registrant’s  fourth  fiscal  quarter  in  the  case  of  an  annual  report)  that  has  materially  affected,  or  is
reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

(5) The  registrant’s  other  certifying  officer(s)  and  I  have  disclosed,  based  on  our  most  recent  evaluation  of  internal  control  over  financial
reporting,  to  the  registrant’s  auditors  and  the  audit  committee  of  the  registrant’s  board  of  directors  (or  persons  performing  the  equivalent
functions):

(a) all significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are
reasonably likely to adversely affect the registrant’s ability to record, process, summarize and report financial information; and

(b) any  fraud,  whether  or  not  material,  that  involves  management  or  other  employees  who  have  a  significant  role  in  the  registrant’s

internal control over financial reporting.

222
Dated: March 24, 2021

By: /s/ Manuel Litchman
  Manuel Litchman, M.D.

President and Chief Executive Officer
(Principal Executive Officer)

 
 
 
 
 
CERTIFICATION PURSUANT TO

SECTION 302 OF THE SARBANES-OXLEY ACT OF 2002 

EXHIBIT 31.2

I, Brian Achenbach, Senior Vice President of Finance & Corporate Controller (Principal Financial Officer), certify that:

(1)

I have reviewed this Annual Report on Form 10-K for the year ended December 31, 2020 of Mustang Bio, Inc. (the registrant);

(2) Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make
the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered
by this report;

(3) Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects,

the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

(4) The registrant’s other certifying officer(s) and I are responsible for establishing and maintaining disclosure controls and procedures (as defined
in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and
15d-15(f)) for the registrant and have:

(a) designed  such  disclosure  controls  and  procedures,  or  caused  such  disclosure  controls  and  procedures  to  be  designed  under  our
supervision,  to  ensure  that  material  information  relating  to  the  registrant  is  made  known  to  us  by  others  within  those  entities,
particularly during the period in which this report is being prepared;

(b) designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under
our  supervision,  to  provide  reasonable  assurance  regarding  the  reliability  of  financial  reporting  and  the  preparation  of  financial
statements for external purposes in accordance with generally accepted accounting principles;

(c) evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about
the  effectiveness  of  the  disclosure  controls  and  procedures,  as  of  the  end  of  the  period  covered  by  this  report  based  on  such
evaluation; and

(d) disclosed  in  the  report  any  change  in  the  registrant’s  internal  control  over  financial  reporting  that  occurred  during  the  registrant’s
most  recent  fiscal  quarter  (the  registrant’s  fourth  fiscal  quarter  in  the  case  of  an  annual  report)  that  has  materially  affected,  or  is
reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

(5) The  registrant’s  other  certifying  officer(s)  and  I  have  disclosed,  based  on  our  most  recent  evaluation  of  internal  control  over  financial
reporting,  to  the  registrant’s  auditors  and  the  audit  committee  of  the  registrant’s  board  of  directors  (or  persons  performing  the  equivalent
functions):

(a) all significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are
reasonably likely to adversely affect the registrant’s ability to record, process, summarize and report financial information; and

(b) any  fraud,  whether  or  not  material,  that  involves  management  or  other  employees  who  have  a  significant  role  in  the  registrant’s

internal control over financial reporting.

22
Dated: March 24, 2021

By: /s/ Brian Achenbach
Brian Achenbach
Senior Vice President of Finance & Corporate Controller
(Principal Financial Officer)  

 
 
 
 
 
 
CERTIFICATION PURSUANT TO 18 U.S.C. SECTION 1350

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002 

EXHIBIT 32.1

In connection with the Annual Report on Form 10-K of Mustang Bio, Inc. (the “Company”) for the period ended December 31, 2020, as filed
with  the  Securities  and  Exchange  Commission  on  the  date  hereof  (the  “Report”),  I,  Manuel  Litchman,  M.D.,  President  and  Chief  Executive
Officer, hereby certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that, to my
knowledge:

(1) The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

(2)  The  information  contained  in  the  Report  fairly  presents,  in  all  material  respects,  the  financial  condition  and  results  of  operations  of  the
Company as of, and for, the periods presented in the Report.

Dated: March 24, 2021

By: /s/ Manuel Litchman
  Manuel Litchman, M.D.,

President and Chief Executive Officer
(Principal Executive Officer)

 
 
 
 
 
 
CERTIFICATION PURSUANT TO 18 U.S.C. SECTION 1350

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

EXHIBIT 32.2

In connection with the Annual Report on Form 10-K of Mustang Bio, Inc. (the “Company”) for the period ended December 31, 2020, as filed
with the Securities and Exchange Commission on the date hereof (the “Report”), I, Brian Achenbach, Senior Vice President Finance & Corporate
Controller, hereby certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that, to my
knowledge:

(1) The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

(2)  The  information  contained  in  the  Report  fairly  presents,  in  all  material  respects,  the  financial  condition  and  results  of  operations  of  the
Company, as of, and for, the periods presented in the Report.

Dated: March 24, 2021

By: /s/ Brian Achenbach
Brian Achenbach
Senior Vice President of Finance & Corporate Controller
(Principal Financial Officer)