Pfizer’s gene therapy trial for Duchenne muscular dystrophy resulted in a young patient’s death. File
| Photo Credit: Reuters

A young patient died due to cardiac arrest after receiving Pfizer’s experimental gene therapy being tested in a mid-stage trial for a muscle-wasting disorder called Duchenne muscular dystrophy(DMD), the drugmaker told Reuters on May 7.

“A fatal serious adverse event was reported as cardiac arrest for a participant in the Phase 2 DAYLIGHT study,” a company spokesperson told Reuters in an emailed response.

The trial is testing boys two to three years of age with Duchenne muscular dystrophy (DMD), a genetic muscle wasting disorder in which most patients lack the protein dystrophin which keeps muscles intact. The disorder affects an estimated one-in-3,500 male births worldwide.

“The patient received the investigational gene therapy, fordadistrogene movaparvovec, in early 2023,” as per a statement from a community letter attributed to the drugmaker’s DMD gene therapy team and posted by a nonprofit advocacy group.

Pfizer did not immediately respond to a Reuters request seeking confirmation on the community letter attributed to the company.

All participants will be followed in the study, for five years after treatment with gene therapy, initiated in August 2022 and estimated to complete in early 2029, as per information updated by the company on a registry of clinical trials.

The company said, together with the independent external data monitoring committee, it is in the process of reviewing the data to understand the potential cause.

The gene therapy candidate is also being tested in the another late-stage DMD study, called CIFFREO, in patients in boys 4 to less than 8 years of age, as per pipeline updates on the drugmaker’s website.

There is not an impact to our expectation of having late-stage results, the company told Reuters in its email.

“We anticipate potentially beginning the primary analysis of the Phase 3 CIFFREO trial of fordadistrogene movaparvovec at the end of this month and sharing top-line results relatively soon,” it added.