Clinical data from spinal muscular atrophy program presented at 20th International WMS Congress

PTC Therapeutics, Inc. (NASDAQ: PTCT), today announced that clinical data from the company's joint development program with Roche and the SMA Foundation in spinal muscular atrophy (SMA) were presented at the 20^th International Congress of the World Muscle Society (WMS) in Brighton, U.K. Results from the first cohort of patients enrolled in the Phase 2 'MOONFISH' trial evaluating oral RG7800, a small molecule modifier of Survival Motor Neuron 2 (SMN2) splicing, were highlighted in a late breaking oral session. The presentation is titled "SMN2 splicing modifier RG7800 increases SMN protein in first study in SMA patients."

"We have now demonstrated, in two independent studies, that treatment with RG7800 shifts SMN2 splicing toward the production of full length SMN mRNA. Most importantly, in the MOONFISH trial we also observed relevant increases in SMN protein levels in whole blood in patients with SMA," said Stuart W. Peltz, Ph.D., Chief Executive Officer, PTC Therapeutics, Inc. "This is important because a two-fold increase of SMN protein levels has the potential to provide meaningful clinical benefit to SMA patients. SMA is a devastating disease with no marketed therapies currently available, and we remain focused on developing an oral therapy for the treatment of this disorder."

MOONFISH is a Phase 2 randomized, double-blind, placebo-controlled study investigating the safety, tolerability, pharmacokinetics and pharmacodynamics of RG7800 with a target enrollment of approximately 64 adult and pediatric patients with SMA. Results from the first cohort that included 13 adult and adolescent SMA patients demonstrated that SMN protein can be increased with RG7800, providing proof of mechanism for oral small molecule SMN2 splicing modifiers. Up to three-fold increases in the ratio of full length SMN2 mRNA to SMN2Δ7 mRNA and up to two-fold increases in SMN protein were observed versus baseline, as measured in whole blood. RG7800 was well tolerated over 12 weeks at a dose of 10 mg once daily.

RG7800 is an orally available small molecule being investigated for its ability to selectively modify the alternative splicing of the SMN2 gene, which is present both in healthy individuals and SMA patients, towards the production of full length mRNA. Preclinical studies in animal models of SMA demonstrated an increase in functional full length SMN protein levels with significant efficacy benefits on survival and motor function. In a Phase 1 clinical study in healthy volunteers, a dose-dependent effect on SMN2 alternative splicing was observed. Dosing in the Phase 2 MOONFISH trial was suspended in April 2015 as a precautionary measure, while a non-clinical safety finding observed in a longer-term animal study is investigated.