Merck, Daiichi Sankyo Withdraw FDA Application for HER3-Targeting ADC After Survival Endpoint Miss

Merck and Daiichi Sankyo have voluntarily withdrawn their FDA application for patritumab deruxtecan (HER3-DXd), an investigational antibody-drug conjugate (ADC) aimed at treating locally advanced or metastatic non-small cell lung cancer (NSCLC) with EGFR mutations12345.

The withdrawal comes after data from the Phase III HERTHENA-Lung02 trial showed the drug did not significantly improve overall survival compared to standard treatments1345.

The decision was also influenced by discussions with the FDA, though the companies did not specify agency feedback; they emphasized the move was unrelated to a previous manufacturing issue that led to a Complete Response Letter in June 2024135.

Patritumab deruxtecan is designed to target the HER3 protein, which is highly expressed in many solid tumors, but the trial's disappointing survival results led to the regulatory setback1345.

Merck and Daiichi Sankyo have not indicated if or when they plan to refile the application145.

Sources:

1. https://www.biospace.com/drug-development/merck-daiichi-sankyo-pull-nsclc-filing-for-adc-citing-underwhelming-survival-findings

2. https://www.morningstar.com/news/dow-jones/202505294119/merck-daiichi-sankyo-withdraw-application-seeking-fda-nod-for-adc

3. https://endpts.com/merck-daiichi-sankyo-scrap-fda-application-for-her3-adc-after-survival-miss/

4. https://www.biopharmadive.com/news/merck-daiichi-withdraw-fda-application-lung-cancer-patritumab-deruxtecan/749243/

5. https://www.geneonline.com/merck-and-daiichi-sankyo-withdraw-fda-application-for-her3-targeting-lung-cancer-drug-after-trial-failures/