FDA Expands Approval of Alhemo for Hemophilia A and B Without Inhibitors

Novo Nordisk has announced the US Food and Drug Administration (FDA) approval of Alhemo (concizumab-mtci) for use as a once-daily subcutaneous prophylactic treatment in people 12 years and older with hemophilia A or B (HA/HB) without inhibitors. This approval expands on the initial indication granted in December 2024 for patients with inhibitors, positioning Alhemo as a versatile option for a broader spectrum of the hemophilia population. Prior to this development, many patients with HA/HB without inhibitors relied on intravenous infusions, often administered multiple times per week.

The expanded approval is grounded in data from the phase 3 explorer8 trial, which demonstrated significant reductions in the annualized bleeding rate (ABR) among patients using Alhemo as prophylaxis. Specifically, the study showed a 79% reduction in ABR in patients with hemophilia B and an 86% reduction in patients with hemophilia A without inhibitors, compared to those receiving no prophylaxis. These results underscore the clinical benefit of Alhemo in reducing both spontaneous and traumatic bleeding episodes. Further reinforcing these findings were reductions in average and median ABRs: patients with hemophilia B had average and median ABRs of 3.1 and 1.6, respectively, compared to 14.8 and 14.9 in the no prophylaxis group. For patients with hemophilia A, the average and median ABRs were 2.7 and 2.9, compared to 19.3 and 19.6 in the control group.

Alhemo operates by targeting and inhibiting tissue factor pathway inhibitor (TFPI), a protein that restricts blood clot formation. By blocking TFPI, Alhemo enhances thrombin generation, compensating for the absence or deficiency of clotting factors VIII or IX, regardless of the presence of inhibitors. This mechanism has allowed Alhemo® to stand out as the first therapy of its kind to be approved for both inhibitor-positive and inhibitor-negative patients.

The explorer8 trial enrolled 156 male patients with HA/HB without inhibitors. Participants were randomized to receive either on-demand treatment or daily Alhemo prophylaxis. The median treatment durations were 24.1 weeks for the on-demand group and 32.1 weeks for the prophylaxis group. An initial loading dose of 1 mg/kg was followed by a maintenance dose of 0.2 mg/kg per day, adjusted based on plasma drug concentrations. The most common adverse events reported were mild, with injection site reactions and headaches each occurring in 7% of patients.

"With today's approval of Alhemo for hemophilia A or B without inhibitors, more people living with these rare blood disorders now have a daily prophylaxis option that may help decrease their bleeding rates,” noted Allison P. Wheeler, MD, Scientific Director, Washington Center for Bleeding Disorders, Seattle, WA.

Reference

FDA approves Alhemo® as once-daily prophylactic treatment to prevent or reduce the frequency of bleeding episodes for adults and children 12 years of age and older with hemophilia A or B (HA/HB) without inhibitors. Press release. Published July 31, 2025. Accessed August 14, 2025. https://www.prnewswire.com/news-releases/fda-approves-alhemo-as-once-daily-prophylactic-treatment-to-prevent-or-reduce-the-frequency-of-bleeding-episodes-for-adults-and-children-12-years-of-age-and-older-with-hemophilia-a-or-b-hahb-without-inhibitors-302519177.html