As many in the community are aware, on Monday, September 28, Pfizer released a statement to the public announcing a change in their Phase III gene therapy trial for Duchenne. We applaud their efforts to inform the community about these events and about the changes to their protocol.  We appreciate their efforts to ensure the safety of the members of our community while advancing gene therapy trials.  Three serious adverse events, including myocarditis or inflammation of the heart tissue, occurred and were attributed to the study drug, fordadistrogene movaparvovec. The study’s External Data Monitoring Committee concluded that individuals with certain dystrophin variants (or mutations) in the dystrophin gene could be at higher risk for these adverse events after being treated with the study drug.

As a result, they have proposed a change in their study protocols which will exclude an individual with Duchenne with an exon deletion, duplication, insertion, or point mutation, affecting exons 9 through 13, or a deletion that affects both exon 29 and exon 30. Changes to the protocol are now being reviewed by regulatory and ethics committees.

Serious adverse events are very concerning and disappointing  in any drug trial in which there is much anticipation and hope.  However, understanding why these adverse events occurred and making changes to the protocol are critical to providing a safe and effective clinical trial experience as well as an ultimate treatment.  We expect to learn much from all sponsors conducting gene therapy clinical research in Duchenne.

This is difficult information for so many, especially boys and families currently participating in clinical trials and those hoping to enroll.  Events such as this remind us that we are in the exciting, yet early stages of gene therapy in Duchenne. Researchers have learned a great deal from those who have participated in trials and will continue to learn more as studies are optimized moving forward. We hope to learn more over the next several days and weeks and will share that information with the community.