Merck, Daiichi Sankyo Say Biologics License Application Withdrawn For Patritumab Deruxtecan

Merck and Daiichi Sankyo have withdrawn their Biologics License Application for patritumab deruxtecan seeking accelerated approval after topline overall survival data from the HERTHENA-Lung02 phase 3 study did not meet statistical significance in EGFR-mutated non-small cell lung cancer patients; further biomarker analyses are being conducted to identify potential patient benefits.

Analysis

Merck & Co. (MRK) and Daiichi Sankyo (DSKYF) have announced the withdrawal of their Biologics License Application (BLA) for patritumab deruxtecan, which was under review by the U.S. Food and Drug Administration for accelerated approval. This significant decision was prompted by disappointing topline overall survival (OS) data from the confirmatory HERTHENA-Lung02 phase 3 study, where patritumab deruxtecan failed to demonstrate statistical significance in improving OS for patients with EGFR-mutated non-small cell lung cancer (NSCLC). This outcome represents a notable setback for the drug's development pipeline, particularly in this lung cancer indication, and follows direct discussions with the FDA. Despite this disappointment, Daiichi Sankyo, through its Global Head of R&D Ken Takeshita, has stated an intention to conduct further biomarker analyses to potentially identify specific patient cohorts who might still benefit from the treatment, aiming to guide its continued, albeit revised, development strategy in lung cancer. The general sentiment surrounding this news is strongly negative, with specific negative sentiment scores of -0.7 for both MRK and DSKYF, reflecting the market's reaction to the clinical trial failure and regulatory withdrawal.

Key Decisions for Investors

• Investors should anticipate potential near-term negative pressure on Merck (MRK) and Daiichi Sankyo (DSKYF) stock prices due to the failure of the HERTHENA-Lung02 trial and the subsequent withdrawal of the BLA for patritumab deruxtecan in this specific lung cancer indication.
• Monitor any forthcoming results from Daiichi Sankyo's planned biomarker analyses, as these will be crucial in determining if there is a viable, albeit narrower, path forward for patritumab deruxtecan in lung cancer, though the probability of success is now reduced.
• Re-evaluate the oncology pipeline valuations for both companies, considering the immediate impact of this clinical setback on projected timelines and revenue potential for patritumab deruxtecan in the EGFR-mutated NSCLC market.