April 28 (Reuters) - Pfizer Inc said on Thursday it would open the first U.S. trial sites for its experimental gene therapy for a muscle-wasting disorder, after the Food and Drug Administration lifted its hold on a late-stage study.
The FDA had put Pfizer's trial request on hold after the death of a patient in another early-stage study of the therapy for Duchenne muscular dystrophy (DMD), which was also paused.
Pfizer said the regulatory clearance came after data reviews and tweaks to the trial to include a seven-day hospitalization period to closely monitor patients receiving the gene therapy.
The late-stage study had been underway in 11 countries before it was halted. So far, Pfizer has received clearance from countries including the United Kingdom, Canada and Taiwan to restart the late-stage study, the drugmaker said.
DMD is caused by changes in a gene, which result in the absence of protein called dystrophin involved in keeping muscle cells intact. It mostly affects boys.
Pfizer's therapy is designed to deliver a shortened version of the human dystrophin gene.
The drugmaker expects nearly all sites for the global late-stage study to open by the end of June.