PTC Therapeutics has managed to slash through the regulatory jungle to find a path forward for Friedreich ataxia med vatiquinone after a pair of failures last year left the biotech reeling.
In a fourth-quarter earnings update Thursday afternoon, PTC executives briefed investors on the results of a type C meeting with the FDA where they pled their case for using a subscale called upright stability to show efficacy using data already collected in the phase 3 MOVE-FA trial.
FA is a rare degenerative disease that causes damage to the spinal cord, peripheral nerves and cerebellum region of the brain. The condition develops in children and teens and gets worse over time, leading to awkward movements and a loss of sensation.
PTC’s candidate for the disorder failed to move the needle on the modified Friedreich Ataxia Rating Scale (mFARS), which measures disease progression. The therapy had little impact on the lower and upper limbs, which led to the failure. Despite the primary endpoint miss, PTC saw a glimmer of efficacy in the data, pointing to the upright stability subscales.
That’s what executives took to the FDA meeting earlier this year, arguing that this data could be used for a new drug application.
CEO Matthew Klein, M.D., explained that since the MOVE-FA study started, there has been an advancement in the understanding of FA and the importance of the upright stability on an ambulant adolescent population. Even an FDA-funded study has shown that, so PTC took the agency’s own evidence to the meetings, he noted.
“We demonstrated significant benefits on the only thing you possibly could show significant benefit on disease progression, and that's the upright stability scale,” Klein said.
Discussions are continuing on the NDA, as well as whether the FDA will accept the application for a regular approval or on an accelerated basis. But after a bleak year and the double failures of vatiquinone in FA as well as a rare seizure disorder called mitochondrial disease-associated seizures (MDAS), PTC now has a path forward.
“What we're most excited about, obviously, is being able to have the potential to submit an NDA based on the MOVE-FA study and what is still a significant unmet need for pediatric and adolescent Friedreich ataxia patients,” Klein said.
PTC is expecting to file the NDA for vatiquinone in late 2024. Klein said an open-label trial is currently ongoing, which will be used to support the package and could also provide confirmatory evidence if the FDA agrees to the accelerated review. For that type of approval, companies can get an advanced go-ahead to market a drug based on biomarker data but must later provide confirmatory evidence to show benefit.
After the FA failure, announced in May 2023, PTC cut staff and conducted a pipeline prioritization. Then in June, vatiquinone failed again in MDAS, causing PTC to move on from the indication.
Beyond vatiquinone, PTC has a number of approved products and is planning to file an NDA for sepiapterin in phenylketonuria by the end of the third quarter this year. Enrollment is also underway for the phase 2 PIVOT-HD trial of PTC518 in Huntington's disease. Twelve-month interim data from that trial is expected in the second quarter.