Merck faces FDA delay for C. diff antibody amid trial data concerns

Kenneth Frazier, Merck CEO

The FDA is not happy with Merck’s ($MRK) monoclonal antibody Clostridium difficile candidate and is demanding more data and analyses from its trials before it can move on any approval.

It’s not as damaging as a complete response letter, but the regulator’s need for more info represents a major amendment to Merck’s original BLA for bezlotoxumab--which will now delay its initial PDUFA goal by 3 months to Oct. 23.

Trials for the drug, which is not a traditional antibiotic but designed as a mAb to prevent the recurrence of C. difficile infection by binding to and neutralizing the C. difficile toxin B, have already been chided by an FDA expert panel.

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Last month the regulator’s advisory group questioned the Big Pharma giant for its small trial size despite the patient population being huge, with others seeing shortcomings in the data. The panel did vote 10-5 (with one abstention) for a recommendation, but most seemed to harbor differing levels of reservation.

The FDA has now specifically asked for the submission of new data and analyses from the MODIFY I and MODIFY II trials, the two studies Merck submitted for its BLA. The drug’s original PDUFA date was set for tomorrow.

“Merck looks forward to continuing to work with the FDA on the review of the bezlotoxumab BLA,” the company said in a brief update posted this morning.

The drug was in-licensed from Medarex, which is now owned by Bristol-Myers Squibb ($BMY), and the University of Massachusetts Medical School back in 2009.

- check out Merck’s statement

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