FDA Grants Priority Review to Hemophilia A With Factor VIII Inhibitors Drug

Emicizumab prophylaxis is designed to bring together factors IXa and X to restore the blood clotting process.

The FDA granted Priority Review to emicizumab prophylaxis, a once-weekly subcutaneous treatment for adults, adolescents, and children with hemophilia A with factor VIII.

The Biologics License Application for emicizumab prophylaxis is based on findings from the phase 3 HAVEN 1 study and interim results from the Phase 3 HAVEN 2 study, according to a press release.

HAVEN 1 is a randomized, multicenter, open-label phase 3 study evaluating the safety, efficacy, and pharmacokinetics of emicizumab prophylaxis in adults and adolescents 12 years and older with hemophilia A with inhibitors to factor VIII.

A total of 109 patients previously treated with bypassing agents (BPAs) on-demand or as prophylaxis were included in the study. Patients previously treated with on-demand BPAs were randomized 2:1 to receive either emicizumab prophylaxis (Arm A) or no prophylaxis (Arm B). Participants previously treated with prophylactic BPAs received emicizumab prophylaxis (Arm C).

The primary endpoint was the number of treated bleeds over time with emicizumab prophylaxis compared with no prophylaxis, according to the release. Secondary endpoints included all bleed rate, joint bleed rate, spontaneous bleed rate, target joint bleed rate, health-related quality of life/health status (HRQoL), and intra-patient comparison to bleed rate on the prior prophylaxis regimen with BPAs or no prophylaxis.

The results of the study showed a clinically meaningful and statistically significant reduction of 87% in treated bleeds with emicizumab prophylaxis compared with on-demand BPAs. All the secondary endpoints were positive, including a statistically significant reduction of 79% in treated bleeds.

The most common adverse events were local injection site reactions, headache, fatigue, upper respiratory infection, and joint pain.

The single-arm, multicenter, open-label phase 3 HAVEN 2 study evaluated the safety, efficacy and pharmacokinetics of once-weekly subcutaneous administration of emicizumab prophylaxis.

After a median of 12 weeks of treatment, the interim analysis included 19 children younger than 12 years with hemophilia A with inhibitors to factor VIII and who require treatment with BPAs.

Interim results were consistent with the positive results from the HAVEN1 study. After 12 weeks, the findings showed only 1 of 19 children receiving emicizumab prophylaxis reported a treated bleed. No joint or muscle bleeds were observed.

“Genentech has a history of developing innovative antibody therapies to address some of the highest unmet medical needs,” Sandra Horning, MD, chief medical officer and head of Global Product Development at Genentech, said in the release. “Results of our phase 3 study in adults and adolescents as well as early phase 3 results in children showed that emicizumab has significant potential to help people with hemophilia A with inhibitors, who face major challenges in preventing and treating bleeds. We are working with the FDA to hopefully bring this new prophylactic treatment option to the hemophilia A inhibitor community as soon as possible.”

A decision on approval from the FDA is expected by February 23, 2018, according to the release.