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.