• Domagrozumab Ph II study did not meet primary endpoint
• Pfizer is also developing a gene therapy, PF-06939926, for DMD
• PF-06939926 has orphan status in the US and Europe

Pfizer Inc. (NYSE: PFE) announced on 8/30/18 that it is terminating two ongoing clinical studies evaluating domagrozumab (PF-06252616) for the treatment of Duchenne muscular dystrophy (DMD): a Phase 2 safety and efficacy study (B5161002) and an open-label extension study (B5161004). The Phase 2 study (B5161002), did not meet its primary efficacy endpoint, which was to demonstrate a difference in the mean change from baseline in 4 Stair Climb (in seconds) following one year of treatment with domagrozumab as compared to placebo in patients with DMD. Further evaluation of the totality of evidence including secondary endpoints did not support a significant treatment effect. The decision comes after a thorough review of data available at the time of the primary analysis, which evaluated all study participants after one year of treatment, as well as those participants who were in the trial beyond one year. The studies were not terminated for safety reasons. Pfizer will continue to review the data to better understand any insights they may provide, and will share results with the scientific and patient community.

“We are disappointed by these results and while we are not progressing with the studies, the data will contribute to a greater understanding of this disease and we will evaluate the total data set to see if there is a place for this medicine in muscular diseases,” said Seng Cheng, PhD, Senior Vice President and Chief Scientific Officer, Pfizer Rare Disease Research Unit. “We are extremely grateful to all those involved with this trial, especially the boys who participated, and their families.”

Pfizer is continuing research in DMD and rare neuromuscular diseases, with the goal of bringing therapies to patients with unmet needs. The company’s continued partnership with advocacy associations and the community is critical to finding innovative therapies for these diseases.

In addition to its domagrozumab program, Pfizer has one ongoing clinical trial in DMD with a gene therapy, PF-06939926, which is an investigational, recombinant AAV9 capsid carrying a truncated or shortened version of the human dystrophin gene (mini-dystrophin) under the control of a human muscle specific promotor. PF-06939926 was granted Orphan Drug and Pediatric Rare Disease Designations by the FDA and Orphan Medical Product Designation by the European Medicines Agency in May 2017.