Atara Biotherapeutics, Inc. is a clinical-stage biopharmaceutical company. Its segment is the business of developing and commercializing therapeutics. It has approximately two groups of product candidates, such as allogeneic or third-party derived antigen-specific T-cells, and molecularly targeted biologics. Its T-cell product candidates include Epstein Barr Virus-cytotoxic T lymphocytes (EBV-CTL), which is in Phase II clinical trials for malignancies associated with EBV; cytomegalovirus (CMV)-CTL, which is in Phase II clinical trials for CMV, and Wilms Tumor 1 (WT1)-CTL, which targets cancers expressing the antigen WT1. Its molecularly targeted product candidates include STM 434, which is in Phase I clinical trial of STM 434 for ovarian cancer and other solid tumors; ATA 777, a fully human antibody targeting Activin A; ATA M43, a fully human anti-Actin-related protein 2-A (ActR2A)/2B monoclonal antibody; STM 217; ActR2B5, and ATA 842, a humanized antibody targeting myostatin.