This morning, EP Vantage reported a temporary UK study halt in dosing after “one serious adverse event that could possibly be related to the investigational drug product” but the halt was for the UK only and did not include any other clinical trial which include Belgium, Czechia, France, Germany, Israel, Italy, Spain, Sweden, and the United States.

For our inquiry, we just got an official statement form Sarepta:

Study 4045-301 (ESSENCE) is a global, randomized double-blind, placebo-controlled study evaluating efficacy and safety in patients with Duchenne muscular dystrophy (DMD) amenable to skipping exons 45 or 53. Patients enrolled in the study at UK study sites have temporarily stopped dosing due to UK specific stopping rules, triggered by one serious adverse event (SAE) that could possibly be related to the investigational drug product. The study remains blinded and the adverse event observed is consistent with those seen in patients with DMD.

 The safety data from all patients in the ESSENCE trial were reviewed by an independent Data Monitoring Committee (DMC). The DMC deemed that dosing could continue for all patients.

 However, based on the UK specific stopping rules of the study, the Medicine and Healthcare products Regulatory Agency (MHRA) required that dosing stop at all UK sites. Sarepta is currently submitting an amendment to the MHRA. Following approval from the MHRA, dosing can be re-initiated at the UK sites.

The SAE affected a single patient, and it might be related to the drug, while hundreds of boys had no SAE with Eteplirsen and many with Golodirsen in the ESSENSE trial and the previous “Phase I/II Study of SRP-4053 in DMD Patients” as well, which made the decision of the independent DMC to let the dosing continue for all other patients.