PTC Therapeutics got an unexpected jolt this morning as European regulators reversed course and recommended approval of its Duchenne Muscular dystrophy drug, ataluren (Translarna).
South Plainfield, NJ-based PTC (NASDAQ: PTCT) said this morning that the Committee for Medicinal Products for Human Use (CHMP)—an advisory panel of the European Medicines Agency (EMA)—has recommended conditional approval of ataluren, which would be used to treat a specific genetic subset of Duchenne patients aged five and older. The EMA will now review the CHMP’s opinion, and make a decision on the drug within a few months. Shares of PTC skyrocketed more than 80 percent in early trading, as the door has been opened to potentially sell ataluren in more than 28 countries.
Ataluren is designed to block the effects of so-called “nonsense mutations,” or single-point alterations in certain genes that stop patients from forming fully functioning versions of the proteins encoded by those genes. Such mutations are the catalyst for a number of genetic diseases, but PTC is initially targeting the ones that underlie Duchenne–a degenerative muscle disease—for some patients, and cystic fibrosis for others.
Ataluren, however, has already failed a few trials, and was previously rejected by the same regulators that recommended it today. In 2011, the drug flunked a mid-stage study in Duchenne patients. It also failed a study in a subset of cystic fibrosis patients. PTC still charged ahead into a Phase 3 study in patients with Duchenne, however, feeling that the previous trial helped give it the information needed to design a study to show that ataluren can produce statistically significant results. That phase 3 trial is expected to produce data next year.
So given that there’s no new data here, what caused the CHMP to change its mind? CEO Stuart Peltz didn’t really specifically answer that question on a conference call this morning—he spoke of talking with the agency about additional analyses, and the “consistency” of the drug’s data in various stages of the disease process, which helped get regulators “comfortable that there was truly a drug effect” that ataluren could be approved based on. But he did say the agency didn’t incorporate any information from PTC’s ongoing Phase 3 study as part of its decision.
The European Medicines Agency, meanwhile, said in its own statement that PTCs drug has shown “some evidence of efficacy…in slowing down the loss of walking ability” in patients with Duchenne—and that the company will have to provide “comprehensive” efficacy data from its ongoing Phase 3 study as part of conditional approval of the drug. Will this be enough for various countries in Europe provide reimbursement for the drug? That remains to be seen.