The small molecule, vatiquinone, had already flunked a Phase III trial, but the company pushed ahead with an approval bid anyway.
The FDA has rejected PTC Therapeutics’ vatiquinone, the company’s proposed treatment for Friedreich’s ataxia in children and adults.
In its complete response letter, the FDA stated that “substantial evidence of efficacy was not demonstrated” and that PTC would need an additional “adequate and well-controlled study” to support a resubmission, the company revealed in its press release Tuesday morning.
Shares of PTC are up about 6% in Tuesday morning trading.
Matthew Klein, the company’s CEO, said in a statement that PTC is planning to meet with the FDA to discuss potential next steps.
Friedreich’s ataxia is a rare neuromuscular disorder, stemming from a mutation in the frataxin gene that leads to mitochondrial dysfunction and cell death. Symptoms include loss of coordination and muscle strength, as well as difficulty speaking, swallowing and breathing. According to PTC, about 25,000 people have Friedreich’s ataxia globally.
Vataquinone is a small molecule that blocks some of the cellular pathways that go awry in patients with frataxin mutations. The drug had previously missed the mark in a Phase III, registration-directed trial back in 2023, failing to meet its primary endpoint of improving gait, stability and limb function after 72 weeks. Nevertheless, based on meeting some secondary endpoints like improving stability, PTC went ahead and sought registration with the FDA.
The only drug on the market for Friedreich’s ataxia is Skyclarys, approved in early 2023 when it was held by Reata Pharmaceuticals. Skyclarys, also a small molecule therapy, works by activating other cellular pathways to reduce the inflammation that Friedreich’s ataxia can cause. Following the drug’s approval, Biogen acquired Reata for about $7.3 billion.
PTC is the latest biotech to receive an FDA rejection in the rare disease space in recent weeks. Last month, Capricor Therapeutics was hit with a surprise CRL for its Duchenne muscular dystrophy asset deramiocel, while Ultragenyx’s UX111 for Sanfilippo syndrome type A also got turned away unexpectedly by the agency.
