If anyone still doubted that KRAS inhibition was a hot area they might have been disabused of this view today. Mirati, a company yet to generate any clinical data with its KRAS inhibitor MRTX849, surged 9%, putting its market cap close to $4bn, on the vague disclosure of further remissions in subjects treated with its rival, Amgen’s AMG 510. On its six-month earnings call last night Amgen disclosed that it had seen responses to AMG 510 in colorectal and appendiceal cancer patients. This adds to the remissions (five in total, four confirmed) in 10 NSCLC subjects that Amgen reported at Asco last month (Asco 2019 – KRAS chase heats up with Amgen data, June 4, 2019). True, the Mirati bull thesis is strengthened by Amgen’s validation of KRAS’s “druggability”, but the more cancers that AMG 510 is shown to work in the higher the bar is raised for competitors. Mirati is expected to unveil the first clinical data with MRTX849 by the end of the year, while in 2020 Johnson & Johnson might do likewise for its KRAS G12C inhibitor ARS-3248.