Merck (NYSE: MRK) stock fell during intraday trading Friday after the FDA declined to approve a lung cancer drug developed in partnership with Daiichi Sankyo.
On Wednesday, the U.S. Food and Drug Administration (FDA) issued a Complete Response Letter (CRL) regarding the Biologics License Application (BLA) seeking accelerated approval for patritumab deruxtecan (HER3-DXd), co-developed by Daiichi Sankyo (OTC: DSKYF) (OTC: DSNKY) and Merck & Co Inc (NYSE: MRK). The application sought accelerated approval for use in adult patients with locally advanced or EGFR-mutated metastatic non-small cell lung cancer (NSCLC) previously treated with two or more systemic therapies.
The CRL is based on findings from an inspection of a third-party manufacturing facility and did not raise concerns regarding the efficacy or safety data submitted for patritumab deruxtecan.
Daiichi Sankyo and Merck are jointly developing patritumab deruxtecan, a first-in-class HER3-directed DXd antibody-drug conjugate (ADC). The FDA had previously granted Priority Review to the BLA for patritumab deruxtecan in December.
The BLA submission was based on primary findings from the pivotal phase 2 HERTHENA-Lung01 trial, involving 225 patients. Results from the trial showed an objective response rate (ORR) of 29.8%. The ORR included one complete response and 66 partial responses, with a median duration of response (DoR) lasting 6.4 months.
Dr. Ken Takeshita, Global Head of R&D at Daiichi Sankyo, expressed commitment to collaborating closely with the FDA and the third-party manufacturer to address the feedback. He underscored their determination to make patritumab deruxtecan available as the first HER3-directed therapy for patients with previously treated EGFR-mutated NSCLC.
Merck (NYSE: MRK) Stock Price Action
MRK stock declined 4.64% on Friday, closing at $123.80, marking a 5.29% decrease for the week. The trading volume was 57,055,456 shares, significantly higher than the average daily volume of 8.28 million.
