U.S. Food and Drug Administration (FDA) for its Duchenne muscular dystrophy (DMD) gene therapy treatment, PF-06939926.
PF-06939926 is currently being evaluated to determine its safety and efficacy in boys with DMD. In May, the company reported promising preliminary results from a Phase Ib study of the gene therapy asset. Data from nine boys with DMD between the ages of six and 12 showed “encouraging efficacy and manageable safety events,” Pfizer said. As BioSpace reported at the time, PF-06939926 demonstrated durable and statistically significant improvements in multiple efficacy endpoints measured 12 months following infusion. These included sustained levels of mini-dystrophin expression and improvements on the North Star Ambulatory Assessment (NSAA) rating scale.
Although the efficacy is promising, there were three serious adverse events in the study. Two appeared to be immune reactions related to complement activation. While they were severe, all three events were fully resolved within two weeks.
PF-06939926 is an investigational, recombinant adeno-associated virus serotype 9 (rAAV9) capsid carrying a shortened version of the human dystrophin gene (mini-dystrophin) under the control of a human muscle-specific promotor. The rAAV9 capsid was chosen as the delivery vector because of its potential to target muscle tissue, Pfizer said.