PTC Therapeutics, in partnership with Roche and the SMA Foundation, recently announced new results from their ongoing Phase 2 trial of RG7800, a small molecule splicing modifier for SMA. The presentation was made at last week’s World Muscle Congress in the United Kingdom.

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.

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. The company will provide the community with an update on the Moonfish trial and their SMN2 splicing modifier program by the end of this year, at the latest.

Previous Updates

Update on Clinical Development of RG7800 (5/7/15)

New Update on Clinical Development of RG7800 (9/1/15)