PTC Therapeutics’ vatiquinone has chalked up back-to-back failures. Weeks after reporting that the drug candidate failed to move the needle in Friedreich's ataxia, the biotech has revealed the prospect was no better than placebo in a rare seizure disorder.
The latest data come from a clinical trial that enrolled 68 children with mitochondrial disease associated seizures (MDAS), a rare disease for which there are no approved disease modifying treatments. PTC bet vatiquinone could improve outcomes by targeting an enzyme that regulates the energetic and oxidative stress pathways that underpin MDAS seizures. The bet failed.
Vatiquinone was no better than placebo at reducing observable motor seizures over 24 weeks of dosing, causing the study to miss its primary endpoint. PTC saw “evidence of treatment effect in reducing seizure frequency in the overall study population and in the largest subgroup of children with Leigh syndrome.” In the subgroup, the biotech reported “benefit” in a life-threatening seizure type and hospitalizations.
Those bright spots were too dim to persuade PTC to pursue further development. While the biotech is yet to share data from the trial, it has already concluded that the results fall short of the bar needed to justify advancing vatiquinone in MDAS.
“While we are disappointed with the results of the study, we hope that there are learnings that can benefit the development of other therapies for patients with mitochondrial disease, who remain without approved treatments for this highly morbid and fatal set of diseases,” PTC CEO Matthew Klein said in a statement.
The setback comes one month after PTC reported that vatiquinone failed in Friedreich's ataxia. At the time of the earlier failure, PTC highlighted “signals of clinical benefit” and outlined plans to talk to regulators about a potential path to approval. The biotech reiterated its intent to discuss bringing the drug candidate to market in Friedreich's ataxia in its statement about the failure in MDAS.