Positive CNS Biomarker and Clinical Effects at Month 12 in Huntington's Disease Patients: Interim PIVOT-HD Results

PTC Therapeutics, Inc. has announced interim findings from their Phase 2 PIVOT-HD trial evaluating PTC518, an investigational drug for Huntington's disease (HD). The 12-month data reveals that PTC518 effectively lowers mutant huntingtin (mHTT) protein levels in both blood and cerebrospinal fluid (CSF) in a dose-dependent manner. The study also showed positive trends in clinical assessments such as Total Motor Score (TMS) and Composite Unified Huntington's Disease Rating Scale (cUHDRS), suggesting that PTC518 may help in slowing the progression of motor symptoms in HD patients. The treatment has been well-tolerated and safe over the 12-month period.

Dr. Matthew B. Klein, CEO of PTC Therapeutics, highlighted that the evidence of central nervous system (CNS) biomarker changes and early clinical effects at the 12-month mark supports the potential of PTC518 as a promising disease-modifying therapy for HD. The durability of mHTT reduction was notable, with a decrease of 22% and 43% in blood levels for the 5mg and 10mg doses, respectively. In the CSF, similar reductions of 21% and 43% were observed for the respective doses. Moreover, PTC518 treatment resulted in a noticeable slowing of motor symptom progression, as indicated by the TMS scores.

Additionally, PTC announced that the U.S. Food and Drug Administration (FDA) has lifted the partial clinical hold on the PIVOT-HD program after reviewing the interim data. This decision paves the way for further development and evaluation of PTC518.

PTC has scheduled a conference call and webcast for June 20th at 8:00 am EDT to discuss these findings. Participants are advised to register and dial in 15 minutes prior to the call. The webcast will be accessible on the Investor section of PTC's website, and a replay will be available for 30 days after the call.

PTC518 is part of PTC's splicing platform technology aimed at treating Huntington's disease. This orally administered small molecule targets the production of the mutated Huntingtin protein responsible for neuronal damage in HD. The drug's ability to penetrate the blood-brain barrier, its selectivity, titratability, and lack of efflux are key differentiating factors.

Huntington's disease is a rare, genetic disorder affecting the central nervous system, caused by a defective gene that produces an abnormal Huntingtin protein. This mutated protein is toxic to neurons, leading to their damage and death. HD typically manifests in individuals in their 30s or 40s, although symptoms can appear earlier, known as Juvenile HD, or even in children under 10, referred to as infantile HD. The disease primarily impacts the brain, resulting in abnormal movements, speech, swallowing and walking difficulties, and various behavioral, cognitive, and motor symptoms. Currently, there is no cure for HD, and no drugs have been approved to delay its onset or progression.

PTC Therapeutics is a global biopharmaceutical company focused on discovering and developing treatments for rare disorders. Its mission is to provide innovative therapies to patients with limited treatment options, leveraging its scientific and clinical expertise and global commercial infrastructure. PTC continues to invest in a diverse pipeline of transformative medicines to maximize value for all stakeholders.