Calithera Biosciences, Inc., a clinical-stage bio-pharmaceutical company, focuses on the discovery and development of small molecule drugs directed against tumor metabolism and tumor immunology targets for the treatment of cancer in the United States. Its lead product candidate is CB-839, an inhibitor of glutaminase, which is in Phase II clinical trial to treat solid tumors. The company also offers INCB001158, an oral inhibitor of arginase that is in Phase I/II clinical trial for the treatment of hematology and oncology. The company is also developing CB-280, an oral arginase inhibitor for the treatment of cystic fibrosis; and CB-708, an orally administered small molecule inhibitor of CD73. It has a license agreement with Mars, Inc. to develop and commercialize Symbioscience's portfolio of arginase inhibitors for use in human healthcare. The company also has clinical trial collaboration with Bristol-Myers Squibb Company to evaluate nivolumab in combination with CB-839. In addition, it