BioMarin Pharmaceuticals released positive results from its global 3-year phase 3 study of valoctocogene roxaparvovec (Roctavian) for patients with hemophilia A. With 134 participants, GENEr8-1 is the largest phase 3 study on gene therapy for hemophilia to date.

“We continue to learn more about the durability, safety and efficacy of valoctocogene roxaparvovec,” said Steven Pipe, MD, professor of pediatrics and pathology at the University of Michigan, Ann Arbor, and an investigator on the study.

“I am encouraged to see the consistent clinical response and the significant number of study participants who remain off prophylaxis after 3 years. This shows the potential transformative impact of this single treatment event for people with severe hemophilia A.”

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The main findings include a reduction of 80% from baseline in the mean annualized bleeding rate and a 94% reduction in the use of factor VIII over 3 years. By the end of year 3, 92% of the participants were off factor VIII prophylaxis and the remainder were able to safely return to prophylaxis.

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The ongoing study is evaluating the superiority of a 6e13 vg/kg dose of valoctocogene roxaparvovec in 134 participants compared with standard factor VIII prophylaxis. A prior study of 112 participants assessed bleeding episodes, factor VIII usage, and health-related quality of life over a 6-month period prior to the administration of valoctocogene roxaparvovec in the GENEr8-1 study.

BioMarin is sponsoring multiple ongoing gene therapy studies in hemophilia A, including several phase 1/2 studies of valoctocogene roxaparvovec as combination therapy or therapy for individuals with pre-existing adeno-associated virus serotype 5 (AAV5) antibodies or active or prior factor VIII inhibitors.


BioMarin announces stable and durable annualized bleed control for Roctavian™ in largest phase 3 gene therapy study in adults with severe hemophilia A; 134-participant study met all primary and secondary efficacy endpoints at 3-year analysis. News release. BioMarin Pharmaceutical Inc; January 8, 2023.