BioMarin gene therapy shows positive Phase III results in hemophilia A

US biotech firm BioMarin Pharmaceutical (Nasdaq: BMRN) saw its shares close down 9.6% at $81.24 on Monday, after it announced positive top-line results from its ongoing global Phase III GENEr8-1 study of valoctocogene roxaparvovec, an investigational gene therapy for the treatment of adults with severe hemophilia A, which has been issued two brand names – Roctavian and ValRox.

This is the largest global Phase III study to date for any gene therapy in any indication, with 134 participants. All participants in the study received a single dose of valoctocogene roxaparvovec and completed a year or more of follow-up.

Data from the GENEr8-1 Phase III study with a mean follow-up of 71.6 weeks showed that in the pre-specified primary analysis for Annualized Bleeding Rate (ABR) a single dose of valoctocogene roxaparvovec significantly reduced ABR by 84% from a prospectively collected 4.8 (median 2.8) at baseline to 0.8 (median 0.0) bleeding episodes per year (p-value <0.0001), among a pre-specified group of prior participants in a non-interventional baseline observational study (rollover population; N=112). 80% of participants were bleed-free starting at week five after treatment.