AACR 2023 – not so fast for Keytruda in biliary tract cancer

Merck & Co looked like it might match Astrazeneca with a first-line biliary track cancer approval, but full results from the Keynote-966 study have added uncertainty. Keynote-966, testing Keytruda plus chemo, was toplined positive for overall survival versus chemo in January, but data just presented at AACR raise fresh questions. Though on a cross-trial basis the all-important OS result looks similar to that seen in Astra’s registrational Topaz-1 study of Imfinzi plus chemo, the numerical PFS benefit in Keynote-966 is not statistically significant. More puzzlingly, there is no remission rate benefit at all in the Merck trial, which also saw a greater rate of severe adverse events overall and a numerically higher rate of treatment-related deaths than Topaz-1. It was already clear that Imfinzi’s win in Topaz-1 was borderline, but with no immunotherapies approved first line the FDA gave the Astra drug a swift green light last September. Whether the agency will be similarly generous to Keytruda is now the question.