BioMarin Pharmaceutical Inc. announced that the Company presented positive results from a two-year analysis of the Phase 3 GENEr8-1 study and an overall safety update of valoctocogene roxaparvovec, an investigational gene therapy for the treatment of adults with severe hemophilia A, at the 15th Annual Virtual Congress of the European Association for Haemophilia and Allied Disorders (EAHAD). This is the largest global Phase 3 study to date for any gene therapy in hemophilia with 134 participants.
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In the GENEr8-1 Phase 3 study, Annualized Bleeding Rate (ABR) was significantly reduced by 4.1 treated bleeds per year (p-value <0.0001), or by 85% from a baseline mean of 4.8 (median 2.8), in the pre-specified primary analysis in participants from a prior non-interventional study (rollover population; N=112; median follow-up of 110 weeks). The percentage of participants with zero treated bleeds increased from 32% on prophylaxis at baseline to 82% during year 1 and 84% during year 2. The mean ABR was 0.8 (median 0.0) through the entire efficacy evaluation period, 0.9 (median 0.0) during year one, and 0.7 (median 0.0) during year two.
Across all participants in the rollover population (N=112), mean annualized Factor VIII infusion rate was reduced by 133 infusions per year (p-value <0.0001) or 98% from baseline. As of the two-year data cut, 95% of participants remain off Factor VIII prophylactic therapy.
“This data demonstrates sustained bleed control is possible at the lower limits of quantification of Factor VIII activity, which may be the start of understanding the durability of gene therapy in hemophilia A, particularly with valoctocogene roxaparvovec,” said Prof. Johnny Mahlangu, a study investigator and Professor in Haematology and Head of School of Pathology in the Faculty of Health Sciences of the University of the Witwatersrand in Johannesburg, South Africa. “I am pleased to see that a high level of study participants remains off prophylaxis reducing the burden of injecting themselves over a hundred times a year.”
“We are pleased to share these transformational data at EAHAD that show this important advance for more than 80% of study participants, who are bleed free and more than 95%, who do not require Factor VIII prophylactic therapy,” said Hank Fuchs, M.D., President of Worldwide Research and Development at BioMarin. “Such outcomes are not afforded by any currently available therapy.”