Sarepta announces data from Part B of MOMENTUM study

Sarepta announced data from Part B of the MOMENTUM study, a global, Phase 2, multi-ascending dose clinical trial of SRP-5051 that enrolled patients aged 8 to 21 years. SRP-5051 is a next-generation peptide phosphorodiamidate morpholino oligomer, or PPMO, treatment for patients with Duchenne muscular dystrophy who are amenable to exon 51 skipping. Data from Part B of MOMENTUM found that at the higher, target dose, approximately 30 mg/kg dosed every four weeks, SRP-5051 resulted in mean dystrophin expression of 5.17%, and mean exon skipping of 11.11% at 28 weeks. Consistent dystrophin expression was seen in ambulatory and non-ambulatory participants at 28 weeks. Hypomagnesemia has previously been identified in patients taking SRP-5051 and was managed and monitored through prophylactic magnesium supplementation as part of the study protocol. High dose results at 28 weeks: 5.17% mean dystrophin expression as measured by western blot 4.53% mean change from baseline; Mean exon skipping of 11.11%, as measured by digital drop polymerase chain reaction and a mean change from baseline in exon skipping of 10.07%. The changes from baseline represent a 12.2-fold increase in dystrophin expression and a 24.6-fold increase in exon skipping compared to a weekly 30 mg/kg dose of eteplirsen at 24 weeks. Low dose results at 28 weeks: 2.81% mean dystrophin expression as measured by western blot;1.60% mean change from baseline; Mean exon skipping of 2.47%, as measured by ddPCR, and a mean change from baseline in exon skipping of 2.00%. The changes from baseline represent a 4.3-fold increase in dystrophin expression and a 4.9-fold increase in exon skipping compared to a weekly 30 mg/kg dose of eteplirsen at 24 weeks. There were seven serious, treatment-emergent adverse events in MOMENTUM Part B, four serious events of hypomagnesemia and three serious cases of hypokalemia. Hypomagnesemia has been seen in earlier clinical studies of SRP-5051 and, throughout MOMENTUM Part B, supplemental magnesium was administered prophylactically. No treatment-related discontinuations occurred in the study.