CHK1 is an important kinase in DNA damage response pathways (DDR). The drug candidate, CCT245737 (now known as SRA737), was identified and developed at The Institute of Cancer Research, London in collaboration with Sareum Ltd. SRA737 has potent anti-tumour activity when given in combination with clinically relevant chemotherapeutics, radiation or as a single agent. It is orally bioavailable, has a favourable toxicology and cardiovascular profile and has the potential to be the best-in-class CHK1 inhibitor. It has been shown to significantly enhance the genotoxic effects of gemcitabine in vitro and in vivo. Two Phase I clinical trials started at the Royal Marsden Hospital in 2016 to investigate SRA737 in combination with standard of care chemotherapy and as a single agent. CPF acquired worldwide rights to SRA737 in September 2013 and the compound was partnered with Sierra Oncology in September 2016. Under the terms of the agreement, Sierra Oncology paid an upfront payment of US$7.0 million And additional payments in the aggregate amount of up to US$321.5 million will become payable upon achievement of certain development, regulatory and commercial milestones. Sierra Oncology will also pay high single to low double digit royalties on net sales.