- The Food and Drug Administration turned down Santhera Pharmaceuticals’ request for an accelerated approval of its Duchenne muscular dystrophy (DMD) drug, Raxone, the company announced Thursday.
- Santhera hoped to secure accelerated approval of the drug for patients not taking concomitant glucocorticoids, based on one phase 3 trial with another trial pending that the company claimed would confirm the drug's efficacy. The FDA decided to await the second trial results and a NDA, the company claimed.
- Santhera is one of several companies trying to develop drugs for DMD: a rare and degenerative muscular disease that halts the production of dystrophin and leads to progressively weaker muscles in patients, usually young men. However, unlike the best-known candidates (Sarepta's eteplirsen and BioMarin's drisapersen), Raxone is not a disease-modifying drug.
With the FDA's decision, Santhera joins a lengthening list of companies that have run into roadblocks in their attempt to develop a drug for the disease. BioMarin's drug was rejected by the FDA earlier this year and review of Sarepta's drug has been delayed after a negative review by an advisory panel. An application from another company, PTC Therapeutics, was turned away for being incomplete.
Santhera's drug, Raxone (idebenone), a small-molecule drug, is intended to improve lung function in DMD patients via its mitochondria-stimulating mode of action. Santhera will soon start enrolling patients for a second phase 3 study; however, results won't be available before the second half of 2019, meaning the drug most likely will not be approved before 2020.
Santhera had hoped to conduct the second study as a confirmatory trial following an accelerated approval, but the FDA wants it to be included as part of the new drug application submission process.
"While we are disappointed that the FDA does not support our plan to file an NDA for Raxone under subpart H for patients not using concomitant glucocorticoids, we now have clarity that successful completion of the SIDEROS trial will provide the necessary data to support NDA filing for Raxone in all DMD patients irrespective of the glucocorticoid use status,” said Thomas Meier, CEO of Santhera.
Meier indicated enrollment would begin in that trial shortly.
The European Medicines Agency, on the other hand, has agreed to review Raxone based on phase 2 evidence and a single phase 3 trial. Approval in Europe could happen as early as next year if regulators there find Santhera's data convincing.
Investors have been watching news on DMD treatments closely as the FDA continues its review of Sarepta's eteplirsen. Originally slated to decide on approval by May 26, the FDA has already missed its deadline. In June, Sarepta said the FDA had asked for more data on eteplirsen, raising some hopes that the new data could set up a more favorable decision.