Merck, Daiichi Withdraw US Approval Request for Lung Cancer Drug

Merck and Daiichi Sankyo have withdrawn their U.S. marketing application for patritumab deruxtecan, an antibody-drug conjugate developed for treating EGFR-mutated non-small cell lung cancer, after Phase 3 trial results failed to show significant overall survival improvement. The withdrawal followed discussions with the FDA and was unrelated to a previous Complete Response Letter concerning third-party manufacturing inspections. Despite this setback, both companies remain confident in the broader development program for patritumab deruxtecan, which includes ongoing clinical trials across multiple cancer types. Analysts maintain a positive outlook on Merck's stock, with an average target price suggesting a notable upside from current levels. This decision underscores the challenges in advancing new cancer therapies despite earlier promising Phase 2 results. Merck and Daiichi Sankyo continue to explore biomarker analyses to identify patients who might benefit from the drug in future studies.