Calithera Biosciences, Inc., a clinical-stage bio-pharmaceutical company, focuses on the discovery and development of small molecule compounds for tumor metabolism and tumor immunology targets for the treatment of cancer in the United States. The company offers INCB001158, an orally bioavailable arginase inhibitor of arginase that is in Phase 1/2 clinical trial for the treatment of hematology and oncology. It is developing CB-280, an oral arginase inhibitor that has completed Phase 1b clinical trial for the treatment of cystic fibrosis and chronic airway infection and ATG-037, an orally-bioavailable small molecule inhibitor of CD73, as well as CB-668, an orally administered inhibitor of the enzyme IL4I1. The company has a license agreement with Mars, Inc. to develop and commercialize Symbioscience's portfolio of arginase inhibitors for use in human healthcare. It also has clinical trial collaboration with Pfizer to evaluate Pfizer's PARP inhibitor talazoparib and CDK4/6 inhibitor palbociclib, each in combination with telaglenasta. In addition, the company has a collaboration and license agreement with Incyte Corporation for the research, development, and commercialization of INCB001158, a small molecule arginase inhibitor for the treatment of hematology and oncology and a license agreement with Antengene Corporation Ltd. for the development and commercialization of CB-708. Calithera Biosciences, Inc. was incorporated in 2010 and is headquartered in South San Francisco, California.