In a recent letter (read below) from Pfizer, it was revealed that a young boy participating in their gene therapy trial for Duchenne muscular dystrophy (DMD) has passed away. The trial, known as Daylight, aimed to study the effects of Pfizer's experimental gene therapy, called fordadistrogene movaparvovec, on boys aged 2 to 3 years old.

The boy had received the gene therapy in early 2023, but the details surrounding his death are still unclear. Pfizer is actively working with investigators to understand what happened.

As a precautionary measure, Pfizer has paused dosing for part of another trial, called CIFFREO, which involves boys with DMD aged 4 to under 8 years old. However, other trials evaluating the gene therapy will continue as planned.

Pfizer emphasizes that the safety of patients in their trials is their top priority, and they are committed to sharing more information with the medical community as it becomes available.

DMD is a rare genetic disease that primar...