FDA Cancer Chief Pazdur Implicated in Replimune Drug Rebuff; Shares Drop 38%

The Food and Drug Administration’s top cancer-drug official, Richard Pazdur, intervened late in the agency’s review of Replimune Group’s experimental melanoma therapy RP1, contributing to the issuance of a Complete Response Letter that blocked the drug’s approval, according to officials cited by STAT. Pazdur’s involvement came after the departure of reviewer Vinay Prasad, who sources say played no substantive role in the final decision. The rejection stunned oncologists who had expected a favorable ruling based on trial data. Twenty-two melanoma specialists from several countries have sent an open letter to the FDA questioning the scientific basis for the decision and asking the agency to revisit the application. Investors reacted swiftly: Replimune shares plunged roughly 38% in pre-market trading on 4 Aug., erasing hundreds of millions of dollars in market value. The episode adds to scrutiny of internal turbulence at the FDA as stakeholders seek clarity on how future cancer-drug reviews will be handled.