Hemophilia is a rare genetic disorder affecting approximately 800,000 people worldwide. It impairs the blood’s ability to clot properly. Hemophilia occurs when there is a deficiency of clotting factor VIII (hemophilia A) or IX (hemophilia B), both of which are necessary to carry out the normal clotting cycle. When either is deficient or absent, bleeding times are prolonged. In clinical management, patients routinely receive intravenous infusions to replace the missing clotting factors.
The FDA has approved Alhemo (concizumab-mtci) as a prophylactic treatment for hemophilia A or B without inhibitors, for patients aged 12 years and older, administered once daily. Approved in December 2024 for patients with inhibitors, Alhemo provides a subcutaneous route for those preferring an alternative to intravenous infusion.
Dr. Anna Windle, Senior Vice President, Clinical Development, Medical and Regulatory Affairs from Novo Nordisk, spoke about the extended FDA approval and called it a milestone for patients living with hemophilia A or B who are seeking a new preventive treatment. The approval is particularly meaningful for patients struggling with hemophilia B with inhibitors to other treatments.
Alhemo is a monoclonal antibody that targets and inhibits tissue factor pathway inhibitor (TFPI), which is a protein that regulates blood clotting by inhibiting thrombin generation. By inhibiting TFPI, Alhemo increases the body’s production of thrombin, a key enzyme that facilitates blood clot formation. This mechanism allows it to work in patients without clotting factors VIII or IX or in patients who have developed inhibitors to standard therapies.
Allison P. Wheeler, Scientific Director -Washington Center for Bleeding Disorders, Seattle, WA, discussed the importance of individualized strategies for bleeding control and continued communication with providers. “The recent approval of Alhemo presents a valuable option for daily prophylaxis that has the potential to decrease bleeding episodes for more patients living with these rare blood disorders.”
FDA approval relied upon data from the pivotal phase 3 Explorer 8 trial, which evaluated Alhemo in patients 12 years and older with hemophilia A or B without inhibitors. The primary objective was to compare the annualized bleeding rate (ABR) in patients receiving Alhemo prophylaxis with that of patients receiving on-demand treatment with Factor VIII or IX. The results of which indicated a statistically significant reduction in ABR.
There was a 79% reduction (ABR ratio: 0.21; 95% CI: 0.10-0.45; p<0.0001) among hemophilia B patients, as compared with an 86% reduction (ABR ratio: 0.14; 95% CI: 0.07-0.29; p<0.0001) among hemophilia A patients. For hemophilia B patients receiving Alhemo, the average ABR was 3.1 (range: 1.9-5.0), and the median ABR was 1.6 (range: 0.0–4.8); for hemophilia B patients receiving on-demand, the average ABR was 14.8 (8.1-26.9), and the median ABR was 14.9 (3.3-22.1). For hemophilia A patients receiving Alhemo, the average ABR was 2.7 (range: 1.6-4.6), and the median ABR was 2.9 (range: 0.0-5.2); for hemophilia A patients receiving on-demand, the average ABR was 19.3 (11.3-33.0), and the median ABR was 19.6 (17.3-30.4).
Alhemo is available in prefilled pens for subcutaneous use in doses of 60 mg/1.5 mL, 150 mg/1.5 mL, and 300 mg/3 mL, administered with a 32-gauge, 4-mm needle. This convenient, customizable option supports treatment for patients with or without inhibitors. The most common side effects of Alhemo, seen in 7 percent of patients, were injection site reactions and headaches.
References: Novo nordisk. 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. Published July 31, 2025. Accessed August 01,2025. 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
