NICE recommends Pfizer’s new once-weekly treatment for haemophilia B on NHS
pharmafile | May 22, 2025 | News story | Market Access, Research and Development | Haematology, Hympavzi, NHS, NICE, Pfizer, haemophilia B, marstacimab
Walton Oaks, 21st May 2025 – Pfizer Ltd announced today that the National Institute for Health and Care Excellence (NICE) has published final draft guidance which recommends Hympavzi ® (marstacimab) as an option for preventing bleeding episodes in people 12 years of age and older, weighing at least 35 kg, with severe haemophilia B (congenital factor IX [9] deficiency, factor 9 activity less than 1%), without factor 9 inhibitors (anti-factor antibodies).[1]
Discovered and developed by Pfizer scientists, marstacimab is the first once-weekly subcutaneous treatment administered via a pre-filled pen for severe haemophilia B to be routinely available on the NHS. It targets the Kunitz 2 domain of tissue factor pathway inhibitor (TFPI), which is a protein that can prevent blood clot formation. By inhibiting TFPI, the medicine can help to restore the body’s ability to stop bleeding.[2]
In the UK, there were more than 2,150 people living with haemophilia B in 2023/2024.[3] Of these, over 380 had severe haemophilia.3 The condition is usually inherited and predominantly affects men, although women can also have haemophilia.[4]
People with haemophilia lack certain proteins needed for blood clotting, meaning it can take longer than normal for bleeding to stop.4 They may also experience spontaneous bleeding in joints and muscles without having had an injury, which could lead to joint damage.4,[5]
Conan McIlwrath, Chair of the Haemophilia Society said: “A subcutaneous treatment option for severe haemophilia B is a positive development which will open up some much-needed choice for people living with the condition. This may hopefully help people move towards more individualised treatment plans, based on what best supports the life they choose to live.”
Eleanor Shelley, Head of Specialty Care, Pfizer UK said: “We have remained committed to researching and developing new treatment options for people living with haemophilia and are pleased that eligible people with severe haemophilia B will now have access to this treatment on the NHS.”
The medicine will be available in England from the end of June via interim funding through the Innovative Medicines Fund (IMF), until it becomes routinely available on the NHS.
The medicine has not been recommended by NICE for the treatment of haemophilia A, however Pfizer remains committed to working to make it available in the future.1 It is also currently under consideration by the Scottish Medicines Consortium (SMC) for use on the NHS in Scotland.
About haemophilia
Haemophilia is a family of rare genetic blood diseases caused by a clotting factor deficiency (FVIII in haemophilia A, FIX in haemophilia B), which prevents normal blood clotting. Haemophilia is diagnosed in early childhood and impacts more than 800,000 people worldwide.[6]
For decades, the most common treatment approach for haemophilia A and B has been factor replacement therapy, which replaces the missing clotting factors. [7] Factor replacement therapies increase the amount of clotting factor in the body to levels that improve clotting, resulting in less bleeding.7
There are a number of different aspects which may determine prophylaxis adherence, they may be patient related, condition related, treatment related, the type of healthcare system and socio-economic aspects.[8] In a patient/physician/specialist nurse survey across six European countries, lack of time for treatment and convenience were among the leading reasons for not using the prescribed amount of clotting factor or skipping treatment administration.[9]
About Hympavzi® (marstacimab)
The UK Medicines and Healthcare products Regulatory Agency (MHRA) granted marketing authorisation for marstacimab in April 2025 for routine prophylaxis of bleeding episodes in patients 12 years of age and older, weighing at least 35 kg, with:
- severe haemophilia A (congenital factor VIII deficiency, FVIII < 1%) without factor VIII inhibitors, or
- severe haemophilia B (congenital factor IX deficiency, FIX < 1%) without factor IX inhibitors.2
The marketing authorisation was based on results from BASIS, a global Phase 3, one-way, cross over, open-label, multicentre study to evaluate the efficacy and safety of marstacimab in 116 adolescent and adult, male participants (aged 12 years and older and ≥35kg) with severe haemophilia A without FVIII inhibitors or severe haemophilia B without FIX inhibitors who previously received “on-demand” (N = 33) or prophylactic (N = 83) treatment with FVIII or FIX.2
In the study, the annualised bleeding rate (ABR) for treated bleeds was 7.85 (95% CI 5.09, 10.61) for routine factor-based prophylaxis during the 6‑month observation period (N = 83) and 5.08 (95% CI 3.40, 6.77) for marstacimab prophylaxis during a 12‑month active treatment period (ATP) (N = 83).2
The most common adverse reactions reported in the study with marstacimab (which may affect more than 1 in 10 people) include reactions at the injection site.2 In addition, headaches, hypertension and pruritus have been reported as common adverse reactions (between 1 in 100 people to 1 in 10 people), and a rash is an uncommon adverse reaction (between 1 in 1000 people to 1 in 100 people).2
About Pfizer: Breakthroughs That Change Patients’ Lives
At Pfizer, we apply science and our global resources to bring therapies to people that extend and significantly improve their lives. We strive to set the standard for quality, safety and value in the discovery, development and manufacture of health care products, including innovative medicines and vaccines. Every day, Pfizer colleagues work across developed and emerging markets to advance wellness, prevention, treatments and cures that challenge the most feared diseases of our time. Consistent with our responsibility as one of the world’s premier innovative biopharmaceutical companies, we collaborate with health care providers, governments and local communities to support and expand access to reliable, affordable health care around the world. For more than 170 years, we have worked to make a difference for all who rely on us. In the UK, Pfizer has its business headquarters in Surrey and is a major supplier of medicines to the NHS. To learn more about our commitments, please visit us at www.pfizer.co.uk or follow us on X (@Pfizer_UK), Facebook (@PfizerUK) and Instagram (@pfizeruk).
References
[1] National Institute for Health and Care Excellence (NICE). Marstacimab for treating severe haemophilia A or severe haemophilia B in people 12 years and over [ID6342]. Available at: Project documents | Marstacimab for treating severe haemophilia A or severe haemophilia B in people 12 years and over [ID6342] | Guidance | NICE [Last accessed: May 2025]
[2] Electronic Medicines Compendium. Hympavzi 150 mg Solution for injection in pre-filled pen. Available at:https://www.medicines.org.uk/emc/product/100776/smpc/print [Last accessed May 2025]
[3] United Kingdom Haemophilia Centres Doctors’ Association. UKHCDO Annual Report 2024. Available at https://www.ukhcdo.org/wp-content/uploads/2024/12/UKHCDO-Annual-Report-2024-2023-24-Data.pdf [Last accessed May 2025]
[4] The Haemophilia Society. Bleeding Disorders: Haemophilia. Available at https://haemophilia.org.uk/bleeding-disorders/haemophilia-a-and-b/ [Last accessed May 2025]
[5] O’Hara J et al. The impact of severe haemophilia and the presence of target joints on health-related quality-of-life. Health Qual Life Outcomes. 2018 May 2;16(1):84.
[6] World Federation of Haemophilia. Global Report on the Annual Global Survey 2022. Available at https://www1.wfh.org/publications/files/pdf-2399.pdf [Last accessed May 2025]
[7] Franchini M, Mannucci PM. Past, present and future of haemophilia: a narrative review. Orphanet Journal of Rare Diseases. 2012;7,24.
[8] Thornburg and Duncan. Treatment adherence in hemophilia. Patient Preference and Adherence. 2017;11,1677–1686.
[9] De Moerloose P, et al. A survey of adherence to haemophilia therapy in six European countries: results and recommendations. Haemophilia. 2008;14(5):931-8.
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