BioMarin to Include Additional Phase 3 Trial for Hemophilia A Gene Therapy

An additional phase 3 study investigating the novel gene therapy BMN 270 for the treatment of hemophilia A will be added as part of BioMarin Pharmaceutical’s development plan for the drug.

Two separate studies will be conducted to examine the safety and efficacy of 2 different doses of BMN 270. According to Hemophilia News Today, both trials are expected to take off in the fourth quarter of 2017.

BMN 270 is a gene therapy designed to deliver the appropriate form of the faulty gene that causes hemophilia A, with the potential goal of returning the normal product of clotting Factor VIII.

“We now plan to move forward as rapidly as possible with 2 separate phase 3 studies with the 4e13 vg/kg and the 6e13 vg/kg doses,” Hank Fuchs, MD, president of Worldwide Research and Development at BioMarin, said in a press release. “By concurrently moving both of these doses into phase 3 development, we have the opportunity to determine if patients may be better served by having 1 or both of these doses commercially available.

“Given the low level of preexisting immunity to AAV5, we expect that approximately 90% of patients would be treatment candidates for BMN 270 based on [these] criteria.”

The decision to add an additional phase 3 study was based on positive results from the phase 1/2 study presented at the International Society on Thrombosis and Hemostasis 2017 Congress in Germany.

Investigators enrolled 15 patients into the ongoing, open-label study and received 4 different doses of BMN 270: either a single 4e13 vg/kg dose administered intravenously, a 6e13 vg/kg dose, or lower doses of the investigational therapy.

After 32 weeks of treatment, 3 of the 6 patients who received 4e13 vg/kg reached or nearly reached the normal range of Factor VIII activity levels. The remaining 3 patients who received the same dose completed 20 weeks upon treatment administration with a change in levels from severe to mild.

The mean annualized bleed rate of patients in the 4e13 vg/kg dose arm was reduced by 92%, and the mean annualized Factor VIII infusions were reduced by 97%.

At week 20 of post-treatment follow-up, all the participants who received the 6e13 vg/kg dose presented mean levels of Factor VIII within normal range, which were still presented by more than 50% a year later.

Investigators expect to include approximately 100 patients with severe hemophilia A in the upcoming phase 3 studies.