Pfizer  announced that CIFFREO, a Phase 3 global, multicenter, randomized, double-blind, placebo-controlled study evaluating the investigational mini-dystrophin gene therapy, fordadistrogene movaparvovec, in ambulatory patients with Duchenne muscular dystrophy (DMD) did not meet its primary endpoint of improvement in motor function among boys 4 to 7 years of age treated with the gene therapy compared to placebo. The primary endpoint in the final analysis was assessed by change in the North Star Ambulatory Assessment (NSAA) at one year after treatment. Key secondary endpoints, including 10-meter run/walk velocity and time to rise from floor velocity, also did not show a significant difference between participants treated with fordadistrogene movaparvovec and placebo.

The overall safety profile of fordadistrogene movaparvovec in the CIFFREO trial was manageable, with mostly mild to moderate adverse events, and treatment-related serious adverse events generally responding to clinical management.

“We are extremely disappointed that these results did not demonstrate the relative improvement in motor function that we had hoped. We plan to share more detailed results from the study at upcoming medical and patient advocacy meetings, with the goal of ensuring that learnings from this trial can help improve future clinical research and development of treatment options that can improve care for boys living with Duchenne muscular dystrophy,” said Dan Levy, MD, PhD, Development Head for Duchenne muscular dystrophy, Pfizer. “We are grateful for the boys, their families, advocates, and the investigators who have participated in this research and the continuing effort to advance treatment options for this debilitating disease.”

Pfizer will continue to closely monitor all participants enrolled in the study and is evaluating appropriate next steps for the program.