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SAREPTA THERAPEUTICS Sarepta Therapeutics Reports Positive Clinical Results from Phase 2 MOMENTUM Study of SRP - 5051 in Patients with Duchenne Muscular Dystrophy Amenable to Skipping Exon 51 5/3/21 • Results suggest a highly potent next - generation treatment that could offer greater efficacy with less frequent dosing • SRP - 5051 dosed monthly at 30 mg / kg delivered mean exon skipping of 10.79 % and mean dystrophin expression of 6.55 % , consistently higher than the other SRP - 5051 dosing cohorts at 12 weeks and weekly eteplirsen at 24 weeks • Sarepta's predictive model indicates that SRP - 5051 at 30 mg / kg will achieve greater than 10 % dystrophin with monthly chronic dosing CAMBRIDGE , Mass . , May 03 , 2021 ( GLOBE NEWSWIRE ) -- Sarepta Therapeutics , Inc. ( NASDAQ : SRPT ) , the leader in precision genetic medicine for rare diseases , today announced positive results from Part A of the MOMENTUM study ( Study 5051-201 ) , a global , Phase 2 , multi - ascending dose clinical trial of SRP - 5051 , its next - generation peptide phosphorodiamidate morpholino oligomer ( PPMO ) treatment for patients with Duchenne muscular dystrophy who are amenable to exon 51 skipping . In biopsies taken at a median of 12 weeks and after only three doses , results from Part A of MOMENTUM study found that the 30 mg / kg of SRP - 5051 dosed monthly resulted in 18 times the exon skipping and eight times the dystrophin production as eteplirsen , dosed weekly for 24 weeks . Exon - skipping and dystrophin production in the 30 mg / kg cohort were also consistently higher than the 20 mg / kg cohort of MOMENTUM . Hypomagnesemia was identified in patients taking SRP - 5051 . Cases have resolved with magnesium supplementation and an analysis of all available data indicate that the hypomagnesemia is monitorable and manageable . " We are pleased to report strong , dose - dependent exon - skipping and dystrophin expression results with monthly dosing of SRP - 5051 - in ambulant and non - ambulant patients . Even at an early timepoint of 12 weeks and after as few as only three doses , these data confirm the potential of Sarepta's next - generation PPMO platform to be a step order improvement over our current PMO platform , and to profoundly impact the course of Duchenne . While we saw exceptional expression after only a few initial doses , our models predict that we will exceed dystrophin expression levels of 10 % of normal or greater over time with SRP - 5051 , " said Doug Ingram , president and chief executive officer , Sarepta . " We are excited to have chosen our target dose for further development . Part A of MOMENTUM is now complete and Sarepta will work with great urgency to discuss the results with regulatory agencies and gain their insights , including the development path to support an accelerated approval of SRP - 5051 in the United States . " Results from the 30 mg / kg dose cohort : • In biopsies taken at a median of week 12 , 30 mg / kg of SRP - 5051 dosed monthly resulted in mean exon skipping of 10.79 % ( n = 4 ) . Exon skipping was measured by digital drop polymerase chain reaction ( ddPCR ) . • This correlates to > 4x increase in exon skipping compared to the 20 mg / kg cohort of SRP - 5051 at 12 weeks ( mean exon skipping of 2.57 % , n = 2 ) and an 18x increase in exon skipping compared to a weekly 30 mg / kg dose of eteplirsen at 24 weeks ( mean exon skipping of 0.59 % , n = 16 ) . • At a median of week 12 , 30 mg / kg of SRP - 5051 resulted in mean dystrophin production of 6.55 % of normal . Dystrophin expression was measured by western blot . o This is twice the dystrophin expression compared to the 20 mg / kg cohort at week 12 ( mean expression of 3.06 % ) and eight times that of the eteplirsen comparison group ( mean expression of 0.82 % ) . There were three serious , treatment - emergent adverse events in two patients in the 30 mg / kg cohort , including two cases of hypomagnesemia . The events were asymptomatic and have resolved with magnesium supplementation . Markers of kidney function have generally been normal and not shown any consistent relationship to the hypomagnesemia . Predictive modeling for dystrophin accumulation that includes assumptions of known turnover of dystrophin in the muscle and an analysis of data generated with the PPMO platform indicates that SRP - 5051 at 30 mg / kg is likely to deliver greater than 10 % dystrophin over time with monthly dosing . Full results will be presented at a future medical meeting . About MOMENTUM ( Study SRP - 5051-201 ) MOMENTUM is a multi - arm , ascending dose study designed to identify the maximum tolerated dose of SRP - 5051 , infused monthly . The study will enroll up to 24 patients , both ambulant and non - ambulant , between the ages of 7 to 21 at sites in the U.S. , Canada , Australia and European Union . The primary endpoint is safety , and secondary and exploratory endpoints include exon - skipping , dystrophin expression and tissue concentration . More information can be found on www.clinicaltrials.gov . About SRP - 5051 SRP - 5051 uses Sarepta's PPMO chemistry and exon - skipping technology to skip exon 51 of the dystrophin gene . SRP - 5051 is designed to bind to exon 51 of dystrophin pre - mRNA , resulting in exclusion of this exon during mRNA processing in patients with genetic mutations that are amenable to