Sierra Oncology, Inc., a late-stage biopharmaceutical company, engages in researching, developing, and commercializing therapies for the treatment of patients with hematology and oncology needs. Its lead drug candidate, momelotinib, is a selective and orally bioavailable Janus kinase 1 (JAK 1), JAK2, and Activin A receptor type 1 (ACVR1) inhibitor. The company also develops SRA515, a selective bromodomain-containing protein 4 inhibitor; and SRA737, an orally bioavailable small molecule inhibitor of Checkpoint kinase 1. It has the license agreements with Carna Biosciences, Inc. to develop and commercialize SRA141, a small molecule kinase inhibitor targeting Cdc7; AstraZeneca AB; and CRT Pioneer Fund LP. The company was formerly known as ProNAi Therapeutics, Inc. and changed its name to Sierra Oncology, Inc. in January 2017. Sierra Oncology, Inc. was incorporated in 2003 and is headquartered in San Mateo, California.