- Dose-dependent benefit on cUHDRS in Stage 2 participants compared to matched natural history cohort, with 52% slowing at 10 mg dose -

- Continued evidence of favorable safety profile - 

- Novartis initiated global Phase 3 INVEST-HD study of votoplam -

- PTC will host a conference call to discuss results today, April 28, at 4:30 pm ET - 

WARREN, N.J., April 28, 2026 /PRNewswire/ -- PTC Therapeutics, Inc. (NASDAQ:PTCT) today reported positive topline results from the 24-month interim analysis of the PIVOT-HD long-term extension study, with favorable dose-dependent effects on disease progression for Stage 2 Huntington's disease (HD) patients following 24 months of votoplam treatment compared to an external natural history cohort.