Page 1

SAREPTA THERAPEUTICS Sarepta Therapeutics Announces First Quarter 2021 Financial Results and Recent Corporate Developments 5/5/21 • Net product sales for the first quarter 2021 of $ 124.9 million , a 24 % increase over the same quarter of prior year CAMBRIDGE , Mass . , May 05 , 2021 ( GLOBE NEWSWIRE ) -- Sarepta Therapeutics , Inc. ( NASDAQ : SRPT ) , the leader in precision genetic medicine for rare diseases , today reported financial results for the first quarter of 2021 . " In the first quarter , we obtained FDA approval for and launched our third RNA therapy for Duchenne , AMONDYS 45TM ( casimersen ) . The first AMONDYS 45 patient was treated within the first week of approval . Serving the community with EXONDYS 51 , VYONDYS 53 , and AMONDYS 45 , we achieved net product revenue of $ 124.9 million , a 24 % increase over the same quarter in 2020 , " stated Doug Ingram , Sarepta's president and CEO . " We also made significant strides in the advancement of our pipeline . Two days ago we announced positive results for the 30 mg / kg cohort of SRP - 5051 , our lead PPMO candidate . As we reported , after a median of only 12 - weeks and three doses , the PPMO showed a significant dose - dependent increase in expression , exhibiting an 18 times greater level of exon skipping and nearly an order of magnitude greater level of dystrophin production as compared to EXONDYS 51 , the currently approved standard of care for those with Duchenne amenable to exon 51 skipping . SRP - 5051 achieved this in about half the time as EXONDYS 51 and with only about 12 % of the dose exposure . " Mr. Ingram continued , “ Also in the first quarter we reported positive data from our ongoing study of SRP - 9003 , our investigational gene therapy for limb - girdle muscular dystrophy Type 2E at the 2021 Muscular Dystrophy Association Annual Clinical and Scientific Conference , reporting robust expression , a good safety profile , good durability to two years , and significantly better functional results than age - matched natural history . For SRP - 9001 , our investigational gene therapy for Duchenne , we have gained invaluable and proprietary insight from the read out of Part 1 of Study 102 which we have used to refine the protocol of our next trial , Study 301. We remain on track to report data in the second quarter from Study 103 ( ENDEAVOR ) , our open - label study evaluating the performance of our commercially representative SRP - 9001 material . " First Quarter 2021 and Recent Corporate Developments : • Reported positive clinical results from Phase 2 MOMENTUM study of SRP - 5051 in patients with Duchenne muscular dystrophy amenable to skipping exon 51 : These results were from the 30 mg / kg arm of Part A of the MOMENTUM study ( Study 5051-201 ) , a global , Phase 2 , multi - ascending dose clinical trial of SRP - 5051 , Sarepta's next - generation peptide phosphorodiamidate morpholino oligomer ( PPMO ) treatment for patients with Duchenne muscular dystrophy amenable to skipping exon 51. Strong , dose - dependent exon - skipping and dystrophin expression results with monthly dosing of SRP - 5051 were observed in ambulant and non - ambulant Duchenne patients when compared to earlier dosing cohorts in Part A and a control group who received weekly dosing of eteplirsen . Hypomagnesemia was identified in patients taking SRP - 5051 . Cases have resolved with oral magnesium supplementation and an analysis of all available data indicate that the hypomagnesemia is monitorable and manageable . Part A of MOMENTUM is now complete , and the Company is engaging regulatory agencies to outline nex steps for the program . Part B of MOMENTUM is intended to be a pivotal trial supporting an accelerated approval in the United States . The full results will be presented at a future medical meeting . Results from the 30 mg / kg dose cohort : • In biopsies taken at 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 ) . o This correlates to a > 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 a weekly 30 mg / kg dose of eteplirsen at 24 weeks ( mean exon skipping of 0.59 % , n = 16 ) . • At 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 % ) . • Sarepta's investigational gene therapy , SRP - 9003 being developed for the treatment of limb - girdle muscular dystrophy Type 2E ( LGMD2E / R4 ) , showed sustained expression and functional improvements at two years after administration : At the 2021 Muscular Dystrophy Association ( MDA ) Annual Clinical and Scientific Conference held in March , the Company presented the first expression data from biopsies of participants in Cohort 1 ( low - dose cohort ) taken two years after a single administration of SRP - 9003 . The results showed sustained protein expression in muscle tissue . In functional outcomes assessments taken two years following treatment in Cohort 1 and one year after treatment in Cohort 2 ( high - dose cohort ) , patients continued to demonstrate stability in their NSAD ( North Star Assessment for Dysferlinopathies )