NEW YORK – Sarepta Therapeutics has discontinued development of SRP-5051, an investigational phosphorodiamidate morpholino oligomer it had been developing for treating Duchenne muscular dystrophy (DMD), the company said Wednesday.
Cambridge, Massachusetts-based Sarepta in January had said it would discuss the development program for SRP-5051, also known as vesleteplirsen, with the US Food and Drug Administration after a Phase II trial showed promising activity.
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 amenable to exon 51 skipping. With this therapy, Sarepta hoped to encourage production of a shorter, but functional, version of dystrophin, the abnormal or deficient protein in DMD patients.
However, the company said it decided to discontinue development of the drug based on "information available to date, including the risk-benefit of the program, feedback from the FDA, and the evolving therapeutic landscape for Duchenne." Sarepta in January had reported seven serious, treatment-related side effects in the Phase II trial, including four instances of hypomagnesemia, or low magnesium, and three cases of hypokalemia, or low potassium. Hypomagnesemia had occurred in previous studies of SRP-5051.
In June 2023, the FDA granted accelerated approval to another DMD therapeutic developed by Sarepta, Elevidys (delandistrogene moxeparvovec), making it the first gene therapy for DMD to reach the market. Although the regulator at the time limited the indication to patients between 4 and 5 years old, the FDA converted the accelerated approval to full approval this June and expanded the indicated age range to cover older patients. The move went against the concerns from some agency reviewers.
The expanded indication has benefited Sarepta financially. On Wednesday, the company reported $467.2 million in revenue for Q3 2024, up 41 percent from $331.8 million in the year-ago quarter. Sarepta attributed the year-over-year revenue increase primarily to Elevidys sales, which totaled $181.0 million in Q3 2024, more than what it was expecting. The company also recorded an additional $9.5 million in royalty revenue from Roche, which is commercializing the gene therapy outside of the US.
"Reflecting our detailed preparation and track record of commercial execution, the launch of Elevidys is proceeding to plan," Sarepta President and CEO Doug Ingram said in a statement. "At the same time, we have made important decisions regarding portfolio prioritization and have made great progress on our pipeline in the quarter."
He added that Sarepta expects to submit a biologics license application with the FDA, seeking approval of an investigational treatment for limb-girdle muscular dystrophy by mid-2025.
Sarepta posted $33.6 million in net income in Q3 2024, or $.34 per share, compared to a net loss of $40.9 million in the year-ago quarter, or $.46 per share. On a non-GAAP basis, the company's EPS was $.62.
As of Sept. 30, the company had $1.40 billion in cash, cash equivalents, and restricted cash and investments.