By Colin Kellaher


The Food and Drug Administration has turned away a proposed lung-cancer drug from Daiichi Sankyo and Merck due to concerns about a third-party manufacturer.

The companies late Wednesday said the FDA issued a so-called complete response letter for their application seeking accelerated approval of patritumab deruxtecan, indicating the agency won't approve the application in its current form.

Merck and Daiichi Sankyo said the FDA cited findings from an inspection of a third-party manufacturing plant, and that the agency didn't identify any issues with the efficacy or safety data the companies submitted for patritumab deruxtecan, a proposed antibody-drug conjugate to treat certain patients with EGFR-mutated non-small cell lung cancer.

Antibody-drug conjugates, known as ADCs, work like a guided missile by pairing antibodies with toxic agents to fight cancer.

Merck and Daiichi Sankyo last year agreed to jointly develop and commercialize patritumab deruxtecan and two other potential ADCs in a deal worth up to $22 billion.

An FDA green light would have made patritumab deruxtecan the first approved therapy that targets the HER3 protein, which is highly expressed across a variety of solid tumors.

Merck and Daiichi Sankyo said they will work closely with the FDA and the unidentified manufacturer to address the agency's feedback as quickly as possible.

In a research note, Citi analyst Hidemaru Yamaguchi said he thinks addressing the issues at the manufacturer would result in an FDA nod for patritumab deruxtecan, with an approval likely in August or September in the best case and by year-end at the worst.

The FDA earlier this week turned away a proposed AbbVie product for controlling motor fluctuations in patients with advanced Parkinson's disease due to concerns about one of that company's third-party manufacturers.


Write to Colin Kellaher at colin.kellaher@wsj.com


(END) Dow Jones Newswires

06-27-24 0650ET