Sierra Oncology, Inc. researches, develops, and commercializes therapies for the treatment of patients with hematology and oncology needs. Its lead drug candidate, momelotinib, is a selective and orally-bioavailable JAK1, JAK2, and ACVR1 inhibitor that has two completed Phase 3 trials for the treatment of myelofibrosis. The company also develops SRA737, an orally bioavailable small molecule inhibitor of Checkpoint kinase 1; and SRA141, an orally bioavailable small molecule inhibitor of cell division cycle 7 kinase. 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 based in San Mateo, California.