BioMarin has released updates on the ongoing clinical trial program for their investigational gene therapy valoctocogene roxaparvovec, which is intended for the treatment of adults with severe hemophilia A. The therapy employs adeno-associated viruses (AAVs) as vectors to carry the genetic codes that prompt the production of the factor VIII (FVIII) protein that is deficient in people with hemophilia A. AAVs are designed to safely deliver the genetic material into living cells to sustained therapeutic effect.
Initiated in 2015, the ongoing Phase 1/2 study to evaluate safety and efficacy of valoctocogene roxaparvovec includes 15 participants with hemophilia A who are now in long term observation following a one-time administration of the therapy. The new data includes updates on two study groups, one in which participants received a larger dose of the therapy and one in which participants received a smaller dose.
The four-year update for the large dose group and three-year update for the lower dose group showed that all participants remain off prophylactic FVIII treatment since receiving their dose of valoctocogene roxaparvovec. According to a recent BioMarin press release, cumulative mean annualized bleed rates (ABR) remain less than one in both groups and below pre-treatment baseline levels. The mean ABR in year four for the large dose group was 1.3, and the mean ABR in year three for the small dose group was 0.5. In addition, six of the seven participants in the large dose group and five of the six participants in the small dose group remain free of spontaneous bleeds over the course of the last year.
“It’s been a privilege to participate in this pioneering research and to observe how the patients on the study have done so much to improve our understanding of gene therapy research for hemophilia A. This additional data is an important step toward a potential first treatment of its kind for this devastating disease,” said Professor John Pasi, MB, ChB, PhD, from Barts and the London School of Medicine and Dentistry; chief investigator for the valoctocogene roxaparvovec Phase 1/2 study, and a principal investigator for the Phase 3 study. “Each year of data increases our knowledge of safety and efficacy and contributes to the growing body of scientific data on gene therapies in general and hemophilia A in particular.”
The Food and Drug Administration is currently reviewing the biologics license application for valoctocogene roxaparvovec.
The data have been submitted as a late-breaking abstract to the upcoming World Federation of Hemophilia (WFH) Virtual Summit to be held June 14-19, 2020.
Source: BioMarin press release dated May 31, 2020 and Clinical Development Update, June 2020