Keytruda’s liver success again raises the Asia question

Can a study conducted in Asian patients serve as the basis for a US approval? This is the question the FDA will answer when it reviews Keynote-394, a trial of Merck & Co’s Keytruda in Chinese, Malaysian, South Korean and Taiwanese liver cancer patients that was yesterday toplined positive. An affirmative answer would spell good news for Coherus, for instance, a company that will hope to challenge Keytruda’s US dominance in front-line lung cancer on the basis of a trial run exclusively in China. Some years ago Richard Pazdur, director of the FDA’s oncology division, courted Chinese companies with promises that China-only trials might suffice, and last month a separate company, Beyondspring, claimed to have been told by the FDA that this was possible as long as pharmacokinetic data for US and Asia patients were similar. Merck says that in Keynote-394 Keytruda beat placebo in extending overall survival of liver cancer patients who had failed Nexavar, and the result could formalise Keytruda’s accelerated approval in this setting. This approval risked being rescinded after the failure of Keynote-240, but an adcom’s decision to retain it, largely because Keynote-394 had yet to read out, could now be vindicated.