Update on Pfizer’s DAYLIGHT Gene Therapy Trial for Duchenne

The Duchenne muscular dystrophy community recently faced a profound loss—a young participant in Pfizer’s Phase 2 DAYLIGHT study (for boys 2 years to less than 4 years of age) passed away due to cardiac arrest, over a year after receiving an investigational micro-dystrophin gene therapy aimed at treating Duchenne. At CureDuchenne, we are devastated to learn of this heartbreaking loss and our hearts go out to this young boy’s family and all those touched by this tragedy. 


Insight into Pfizer’s DAYLIGHT Trial

Pfizer’s micro-dystrophin gene therapy trial has been investigating the effects of fordadistrogene movaparvovec, a gene therapy that holds promise for altering the debilitating course of Duchenne.  

The gene therapy candidate is also being tested in another late-stage DMD study, called CIFFREO, in DMD boys 4 to less than 8 years of age. While Pfizer has decided to pause dosing associated with the cross-over portion of the CIFFREO study, the company anticipates beginning the primary analysis of the Phase 3 CIFFREO trial at the end of this month and sharing top-line results relatively soon.

Focus on Safety in Clinical Trials

The untimely loss occurred more than one year after the initial administration of the gene therapy, highlighting the importance of long-term follow-up of clinical trial participants. Following this tragic event, Pfizer has implemented a temporary pause in certain aspects of the trial to conduct a thorough review and ensure the utmost safety for all participants. This pause reflects the rigorous safety protocols that govern clinical research, particularly in trials involving vulnerable populations such as young children with Duchenne.

Support and Resources for the Duchenne Community

Any loss within our Duchenne community deeply affects us all. At CureDuchenne, we understand the emotional toll such news can take and are committed to supporting each family during this difficult time. If you are feeling overwhelmed or have questions about the implications of this event for new or ongoing clinical trials in Duchenne, please reach out. You are not alone, and together, we can navigate these challenges.

Looking Forward with Hope and Determination

The mission to find effective treatments for Duchenne muscular dystrophy continues. We are forever grateful to the broader Duchenne community for their critical participation in clinical trials and recognize that substantial advances to treatment require Biopharma/community partnerships to drive innovation.

As we mourn the loss of a young hero, we are reminded of the critical importance of our mission. CureDuchenne is committed to the development of safe and effective therapies and will work tirelessly to support families every step of the way in their journey. Our thoughts are with the family of the young boy, and we are here to support the community in every way possible.

To schedule a 1:1 with CureDuchenne’s experts, click here.

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