Sarepta Therapeutics has announced the discontinuation of its vesleteplirsen program, a next-generation exon 51-skipping therapy intended for Duchenne muscular dystrophy (DMD), following discussions with the FDA and an internal risk-benefit assessment. This decision was revealed during the company's third-quarter earnings call, with CEO Doug Ingram citing the evolving DMD treatment landscape, including the approval and subsequent success of Elevidys, as a key factor.
The Phase II MOMENTUM study assessed vesleteplirsen in patients aged 8 to 21 years amenable to exon 51 skipping. While initial data were positive, cases of hypomagnesemia, or abnormally low magnesium levels, emerged and persisted even after treatment cessation. According to Sarepta's head of R&D, Louise Rodino-Klapac, the FDA indicated that the accelerated approval pathway was not open for vesleteplirsen based on the available data.
Impact on Sarepta's Strategy
Jefferies analysts suggest that the discontinuation of vesleteplirsen will have minimal impact on Sarepta's stock, as it potentially increases the sales upside for Elevidys and Exondys. This strategic shift underscores Sarepta's focus on its approved therapies and their expanded applications within the DMD market.
Elevidys' Commercial Success
Elevidys, the first gene therapy approved for DMD, reported a net revenue of $181 million in the third quarter, surpassing previous guidance. Including sales from Roche, Sarepta's commercialization partner outside the U.S., Elevidys generated $190.5 million for the quarter. This represents a 49% growth over Q3 2023, according to Jefferies. Mizuho’s Uy Ear described the results as "undisputedly a strong start to commercializing the expanded Elevidys label."
Elevidys' Approval History and Data
Elevidys initially received accelerated approval from the FDA in June 2023 for ambulatory DMD patients aged 4 to 5 years. A year later, this was converted to full approval with an expanded label covering ambulatory patients 4 years and older, as well as accelerated approval for non-ambulatory patients. However, the initial approval faced scrutiny due to questions regarding its efficacy, particularly after the gene therapy failed to meet the primary functional endpoint in its confirmatory trial in October 2023. Recent presentations at the World Muscle Society meeting in Prague highlighted the need for more data, especially concerning the newer patient populations included in the expanded label.
Financial Performance
Sarepta reported total revenue of $467.2 million for the third quarter, a significant increase from $331.8 million in the same period in 2023. This financial performance reflects the growing impact of Elevidys on Sarepta's overall revenue stream.
