Sierra Oncology, Inc. is a clinical-stage drug development company. It develops and markets drugs for the treatment of cancer. The product pipeline consists of SRA737 and SRA141. SRA737 is an orally bioavailable small molecule inhibitor of Checkpoint kinase 1, a key cell cycle checkpoint and central regulator of the DNA Damage Response network. SRA141 is an orally available small molecule inhibitor of cell division cycle 7kinase. Sierra Oncology, Inc., formerly known as ProNAi Therapeutics, Inc., is headquatered in Vancouver, Canada.