- PTC Therapeutics, which in February saw its treatment for Duchenne muscular dystrophy (DMD) snubbed by the Food and Drug Administration, on Monday revealed the regulator had denied the company's appeal of the initial refuse to file decision.
- Perhaps emboldened by the recent success of Sarepta with Exondys 51 (eteplirsen), PTC said that a proper assessment of its drug Translarna (ataluren) would require a full review from the FDA, including an advisory committee meeting with input from patient advocates.
- PTC intends to further escalate its appeal to the next level of the FDA's dispute resolution. But investors took little solace in the company's persistence, pushing PTC stock down by over 25% in early trading Monday.
PTC is having no luck in convincing the FDA to review its DMD drug.
The U.S. regulator issued a refuse to file letter in February, judging the initial application "not sufficiently complete," according to a statement from the company at the time.
Prior to filing, the New Jersey-based biopharma had conducted a double-blind, placebo controlled Phase 3 study of ataluren, but the drug failed to show a statistically significant improvement in the 6-minute walk test. PTC decided to move ahead anyway, citing benefits seen among pre-specified subgroups.
A month after receiving the refuse to file letter, PTC laid off nearly a fifth of its workforce.
Now the FDA has rejected PTC's first appeal of that February decision. Despite the further setback, PTC said it would continue its efforts to win a review from the regulator.
"This is an iterative process and the company anticipates that multiple cycles of appeals to progressively higher levels of the FDA may be required," the company said in a statement.
It appears PTC hopes to capitalize on Sarepta's recent success in winning a conditional approval for its DMD treatment. The company's statement argued ataluren should be granted a full review, just as Sarepta and BioMarin received.
Sarepta was able to convince the FDA to approve Exondys 51 despite shaky clinical evidence, boosted by strong patient advocacy efforts throughout the review process. PTC may be itching to make a similar case, although the urgency and pressure on the FDA would be less after approval of Exondys 51.
Ataluren is designed to treat DMD patients with nonsense mutation forms of the muscle-wasting disease, a different patient population than the estimated 13% of DMD patients for which Exondys 51 is approved.
PTC is also running into difficulties in Europe, where ataluren received conditional approval in 2014 subject to annual renewal. After delaying ataluren's annual review this year, European regulators have filed a request for supplemental information, including one "major objection," PTC said. The objection is tied to the efficacy and overall risk-benefit of ataluren.
If PTC is granted an extension of its conditional approval, the company believes it would be required to conduct a new clinical trial of its drug.
PTC said it expects European regulators to make a decided on renewal of ataluren's approval before the end of 2016.