Aptevo Therapeutics Inc., a clinical-stage biotechnology company, is working on developing immunotherapeutic candidates in the United States for various types of cancer. Its lead clinical candidate, APVO436, is a bispecific T-cell engaging antibody candidate, which is in Phase 1b clinical trials for acute myelogenous leukemia and myelodysplastic syndrome. The company has some preclinical candidates in the pipeline, such as ALG.APV-527, an investigational bispecific ADAPTIR candidate, which targets 4-1BB (CD137) and 5T4, a tumor antigen expressed in different types of cancers. Additionally, the company has developed APVO603, a dual agonist bispecific antibody that targets 4-1BB and OX40. The company is also working on APVO442, a bispecific candidate based on the ADAPTIR-FLEX platform technology, which enhances the biodistribution of drugs to PSMA-positive tumors for the treatment of prostate cancer. Aptevo Therapeutics Inc. has a collaboration and option agreement with Alligator Bioscience AB to develop ALG.APV-527. The company, headquartered in Seattle, Washington, was incorporated in 2016.