November 6, 2024
Dear Duchenne Community,
We are writing to share news of our decision to discontinue development of SRP-5051, also known as vesleteplirsen, our investigational peptide-conjugated PMO, or PPMO, to treat people with Duchenne who are amenable to exon 51 skipping. This means dosing in the MOMENTUM study, SRP-5051-201, has stopped.
When we set out to develop SRP-5051, our goal was to be able to offer people living with Duchenne and their families a safe and effective treatment option that would build upon our FDA-approved PMO exon skipping therapy. While we were encouraged by the dystrophin expression results with SRP-5051, early in the study a risk of hypomagnesemia (low blood magnesium levels) became known, an issue that was considered monitorable and manageable. In some participants we have now seen prolonged hypomagnesemia during the study and following treatment discontinuation. Additionally, some patients experienced decline in eGFR, a test that measures kidney function. Safety is our number one priority. Considerations about long-term safety and tolerability led to the decision to discontinue development of SRP-5051. Drug development is complex, and decisions like these are difficult. As every one of our programs progresses, we have to check in with ourselves and ask if the data continue to support our belief that this is the best we can do for patients and recognize that the answer may not always be yes.
We recognize this news may be deeply disappointing for the Duchenne community, especially those who have participated in studies of SRP-5051. We share in the disappointment that SRP-5051 will not be part of the solution for Duchenne families. As a committed partner to the Duchenne community, Sarepta remains steadfast in bringing forward safe therapeutic solutions, as fast and responsibly as possible. Below, please find answers to some questions that we anticipate from the community.
In closing and most importantly, we would like to acknowledge and express our deep appreciation to participants in this study, family members, and study teams for their contribution to this research. The time, collaboration, and commitment invested through every part of the SRP-5051 studies have been incredibly important and appreciated. While SRP-5051 is not moving forward, its learnings, which would not have been possible without the Duchenne community, will help propel the field forward.
Kindly,
The Sarepta Patient Affairs Team
[email protected]
Questions and Answers related to this announcement:
What are the next steps related to this study?
We learn something from every study in Duchenne. Over the coming months, participants will be scheduling their final visit, and MOMENTUM study activities will be winding down. Following this, we plan to share study results in a scientific forum to support advancement in the field of RNA-targeted therapies. We encourage study participants or family members who have questions about the next steps to reach out to their clinical study site.
Will you be sharing individual participant data with participants from the study?
In time, individual participant results will be shared with study doctors for their discussion with trial participants. Though we will try to move data sharing along as quickly as possible, the process is complex, involving multiple entities and a large amount of data, and will take time. Sharing individual participant data will follow the last participant’s last visit by about one year. We encourage study participants or family members who have questions about the next steps to reach out to their clinical study site.
Why didn’t Sarepta call families who are in the study to share the news?
All MOMENTUM clinical study sites have been informed of this decision, and the study teams are in the process of informing the study participants and families. Because MOMENTUM is a global study with clinical sites in several countries and across different time zones, communicating this news to families may take some time, and we acknowledge that members of the community might learn of this news at different times and in diverse ways. Consistent with guidelines on conducting clinical studies, as the study sponsor Sarepta does not have access to lists of participants and their contact information. Direct communication with trial participants and families is managed by the study doctors.
Does this impact your other programs (approved or investigational)?
The decision to discontinue this program has no impact on our other approved therapies and/or clinical study programs, including Sarepta’s PMO exon skipping therapies and Sarepta’s gene therapy. We believe the concerns are related to the specific cell penetrating peptide used in SRP-5051. There is no evidence of these safety concerns in the PMO program.