FDA hits trap door button on Merck's weak ridaforolimus bid

In another self-inflicted wound for Merck, the FDA has handed back its new drug application for ridaforolimus, saying the pharma giant will need to run additional clinical trials to test its effectiveness on sarcomas before it can issue an approval.

The decision couldn't have come as a surprise to Merck ($MRK), or Ariad ($ARIA), which licensed the drug out. The FDA staff review raised serious concerns about exposing patients to the side effects of the drug while offering just a few weeks of added progression-free survival. And the agency's panel of experts gave a thumbs-down on the application by a lopsided 13-to-one vote against approval.

Ridaforolimus isn't finished yet, though. Merck is studying the drug in other tumor types. And Ariad is completely focused on ponatinib for chronic myeloid leukemia. A few days ago Ariad reported at ASCO that ponatinib registered a significant response among patients in a clinical study. Ponatinib stands a much better chance at the regulatory agencies as Ariad looks to make the big transition from a research-only outfit to a company with marketing operations in the U.S. and Europe.

Perhaps the biggest implication for the CRL rejection is for Merck, which has failed to impress the industry either with its late-stage pipeline or its R&D savvy. One of its next big drugs in the pipeline is the sleep therapy suvorexant, which faces some major league competition if it makes it to a crowded market. Merck, though, remains committed to a program into which it has already invested heavily.

"Merck remains confident in the potential of ridaforolimus," said Eric Rubin, M.D., vice president, Clinical Research Oncology, Merck. "We will continue to work closely with the FDA to define potential paths forward for this investigational therapy."

- here's the press release