Capricor shares soar as potential FDA lifeline revives Duchenne drug hopes

Cantor analyst Kristen Kluska called the FDA's willingness to review the new muscle data a "potentially positive surprise", noting the agency would have little reason to extend the deadline if it had already decided against approval.

Shares of Capricor were trading at $7.16 in the morning, though still down sharply from $19.70 before last month's FDA setbacks.

The U.S. Department of Health and Human Services, which oversees the FDA, did not immediately respond to a Reuters request for comment on the amended submission and potential new review timeline.

Roth Capital analysts said the FDA is likely to treat Capricor's resubmission as a "major amendment", extending the review timeline by about three months.

Capricor, which had $237.9 million in cash at the end of June, said it is pacing its commercial launch spending while it awaits regulatory clarity.

"Apparent regulatory pivot supports the upside case" for approval, said Oppenheimer analysts.

The panel echoed FDA staff concerns that Capricor had changed how it measured the trial's main outcomes, and questioned whether enrolled patients even had Duchenne-related cardiomyopathy, given their normal heart function at baseline.

Capricor Chief Executive Linda Marban said late on Thursday the company will submit an amendment with new 24-month data focused on improving upper limb muscle function, the main goal of its late-stage study.

Some panel members had been more receptive to the treatment's arm and hand function data than its contested heart benefits.

The FDA has said it is willing to review this new information and will push back its decision deadline once it gets the data, Marban said. The agency's decision was expected by August 22.