Sarepta Therapeutics has announced the discontinuation of SRP-5051, an experimental drug for Duchenne muscular dystrophy (DMD), citing safety concerns and the shifting therapeutic landscape following the approval and strong sales of its gene therapy, Elevidys. The decision was revealed during a conference call with analysts on Wednesday, where company executives detailed the factors contributing to this strategic shift.
Factors Influencing the Decision
Chief Scientific Officer Louise Rodino-Klapac highlighted that safety concerns, feedback from the Food and Drug Administration (FDA), and the successful introduction of Elevidys all played a role in the decision to halt SRP-5051's development. SRP-5051, designed for DMD patients with exon 51 mutations, aimed to improve upon Sarepta's existing exon-skipping therapy, Exondys 51, but trials revealed persistent hypomagnesia (low magnesium levels) in some patients, even after treatment cessation.
Elevidys Sales Surge
Meanwhile, Elevidys, Sarepta's gene therapy for DMD, has experienced a significant revenue increase. Third-quarter sales reached $181 million, surpassing analyst estimates of $160 million, a substantial rise from the $122 million reported in the second quarter. This surge followed the FDA's decision in late June to expand Elevidys' label, making it accessible to a broader population of individuals with Duchenne muscular dystrophy. Sarepta also earned $9.5 million in royalties from Roche, which commercializes Elevidys outside the U.S.
Analyst Perspectives
Analysts view the discontinuation of SRP-5051 as disappointing but anticipate that Elevidys' commercial success will compensate for the loss. Leerink Partners analyst Joseph Schwartz projects that Elevidys sales could exceed $2 billion next year. William Blair analyst Sami Corwin supports Sarepta's decision to discontinue the PPMO franchise, given the promising trajectory of its gene therapy.
Impact on Exon-Skipping Drugs
Sarepta's existing exon-skipping drugs, including Exondys 51, are expected to maintain their growth trajectory, generating approximately $249 million in combined revenue during the third quarter. Analysts predict that competition from Elevidys will have a limited impact on these drugs until after next year. SRP-5051 was seen as a next-generation treatment to build on Exondys 51, utilizing an improved exon-skipping technology. While studies suggested SRP-5051 might be more effective than Exondys 51, the safety concerns ultimately led to its discontinuation.
