PTC Therapeutics (PTCT) Earnings Call Presentation

Efficacy & Biomarkers - PTC518 treatment resulted in dose-dependent blood HTT lowering in both Stage 2 and Stage 3 subjects, with reductions of -23.4% and -39.1% in Stage 2, and -23.3% and -36.1% in Stage 3 at Month 12[13] - Favorable trends of NfL lowering were observed in Stage 2 subjects, with a -6.5% change from baseline to Month 12 in the PTC518 5 mg group and -2.8% in the 10 mg group[15] - At Month 24, dose-dependent NfL lowering from baseline was observed, with a -9.0% change in the PTC518 10 mg group (p=0.03) and -13.9% in the 5mg group (p=0.12)[32] - Compared to a propensity-matched natural history control, PTC518 showed a favorable effect on cUHDRS at Month 24[28] Safety & Tolerability - PTC518 treatment showed a favorable safety and tolerability profile at Month 12, with similar adverse event profiles across all treatment groups and disease stages, including placebo[19, 20, 21] - No treatment-related SAEs nor NfL spikes were reported at Month 24, and PTC518 was well-tolerated with no dose-limiting toxicities[35] Clinical Trends - Early signals of favorable effect on clinical scales were observed in Stage 2 subjects at Month 12[18] - Dose-dependent clinical trends of disease slowing relative to matched natural history were observed at Month 24[37] Study Design & Endpoints - The study met the primary endpoint of blood HTT protein lowering at Week 12, with durable dose-dependent lowering at Month 12[9, 13] - The PIVOT-HD study included a 12-week placebo-controlled phase followed by a 48-month open-label extension study[7] Natural History Comparison - A natural history comparative analysis utilizing the ENROLL-HD disease registry identified 1,045 subjects matched to the enrollment criteria of PIVOT-HD[26]