Fig. 1: Phenotypic and dysmorphic features of patient 1 (A and B),...

First NHS Patient Treated With CSL Behring's Haemophilia B Gene Therapy Hemgenix

The first patient in the UK has been treated by the NHS with CSL Behring's haemophilia B gene therapy Hemgenix (etranacogene dezaparvovec).

The patient from the North East of England was treated at Guys & St Thomas's NHS Foundation Trust in London and may no longer require regular infusions to help their blood clot.

Affecting more than 2,000 people in the UK, haemophilia B is a genetic bleeding disorder resulting from missing or insufficient levels of clotting factor IX (FIX).

Patients with severe cases of the disease currently require lifelong treatment with intravenous FIX, which can still leave them vulnerable to breakthrough bleeds and pain in the days before infusions.

CSL's Hemgenix addresses the underlying genetic cause of haemophilia B by enabling the body to continuously produce FIX, and is the only one-time gene therapy to be approved in the UK for adults with severe or moderately severe haemophilia B without a history of FIX inhibitors.

Pu-Lin Luo, consultant haematologist at Guy's and St Thomas', said: "This is a big step forward in our ability to manage haemophilia B and could change the lives of some of our patients. It is also a testament to the advancement of cell and gene therapies in the UK and these are exciting times."

CSL Behring said it will continue to work "closely and collaboratively" with the selected gene therapy centres to ensure that further eligible patients across the country will be able to access Hemgenix.

The National Institute for Health and Care Excellence's decision to recommend Hemgenix for use on the NHS in June 2024 was supported by positive results from the late-stage HOPE-B trial, in which a single infusion of Hemgenix demonstrated significant increases in mean FIX activity levels of 36.9% at 18 months.

These increases were sustained at 36.7% at 24 months and 38.6% at 36 months and led to an adjusted annualised bleed rate reduction of 64% at 24 and 36 months post-dose compared to the six-month lead-in period.

CSL Behring also presented updated results from the ongoing trial in February this year.

Data presented at this year's Annual Congress of the European Association for Haemophilia and Allied Disorders showed that mean factor IX activity levels remained at near normal levels of 37% through four years post-treatment, and mean adjusted annualised bleeding rate for all bleeds was reduced by approximately 90% from lead-in to year four.

Marstacimab Improved Key Bleeding Outcomes In Hemophilia A Or B

Primary and secondary end points were demonstrated in a phase 3 trial of subcutaneous marstacimab as treatment for patients with hemophilia A or B.

Phase 3 results highlighted the continued positive results of marstacimab (Hympavzi; Pfizer) when treating patients with hemophilia A or B. The phase 3 trial met its primary and secondary end points of improving key bleeding outcomes when compared with on-demand treatment.1

Hemophilia is a rare genetic blood disease that affects approximately 33,000 people in the US.2 The condition is characterized by a clotting factor deficiency. This causes a delay in blood clotting that increases the risk of bruising and bleeding in those living with the condition. Joint scarring and damage are also possible due to the increased risk of painful bleeding inside the joints.1 Replacing the clotting factors in the blood is used as the primary treatment for those with hemophilia, with life expectancy estimated to be the same as those without hemophilia when patients are treated regularly.2

Marstacimab was effective in reducing annual bleeding rate in individuals living with hemophiliaImage credit: jarun011 - stock.Adobe.Com

Marstacimab is a once-weekly subcutaneous treatment that has received regulatory approvals in both the US and in Europe for patients with hemophilia A without factor VIII inhibitors or hemophilia B without factor IX inhibitors.1 The treatment was the first medicine for hemophilia that was approved when administered in a prefilled, auto-injector pen and the first once-weekly prophylactic treatment for people living with hemophilia B specifically.3 The approval came based on the preliminary results of the BASIS trial (NCT03938792) which found that the annualized bleeding rate (ABR) was reduced by 35% compared with prophylaxis and 92% when compared with on-demand treatment. Adverse reactions included headache, injection site reactions, and pruritus. The results published today build on the relationships already established in the preliminary findings of the data used for the initial approval of marstacimab.

The BASIS study was a phase 3, open-label, multicenter study that aimed to test the efficacy of marstacimab in patients with severe hemophilia of factor VIII activity of less than 1% or moderately severe to severe hemophilia B of factor IX activity of less than 2%.1 All 48 participants of the study were aged between 12 and 75 years and were living with hemophilia with inhibitors. All participants were treated for 12 months either on marstacimab or an on-demand intravenous regimen with bypassing agents. Participants received prophylaxis during the treatment period. The primary end point was the measurement of the ABR after 12 months with marstacimab compared with on-demand replacement therapy.

The phase 3 trial results showed that treatment with marstacimab led to "a statistically significant and clinically relevant reduction in [ABR] of treated bleeds in people living with severe hemophilia A or hemophilia B with inhibitors." Marstacimab reduced ABR over 12 months by 93% (1.39 vs 19.78 for on-demand therapy). Spontaneous bleeds, joint bleeds, target joint bleeds, and total bleeds all had superior results when patients used marstacimab.

"These encouraging results demonstrate HYMPAVZI's potential to help people living with hemophilia A or B with inhibitors, meeting an important need for patients with antibodies that neutralize most factor-based prophylactic options used to manage bleeding episodes," said Michael Vincent, MD, PhD, the chief inflammation and immunology officer at Pfizer.

These results build on the positive results found when using marstacimab in patients with hemophilia B and also provide positive results in patients with hemophilia A, offering promise in long-term treatments for both conditions.

References

1. Pfizer announces positive topline phase 3 results for HYMPAVZI in hemophilia A or B with inhibitors. News release; Pfizer. June 26, 2025. Accessed June 26, 2025.

2. Hemophilia. Cleveland Clinic. Updated November 14, 2022. Accessed June 25, 2025. Https://my.Clevelandclinic.Org/health/diseases/14083-hemophilia

3. Caffrey M. FDA approves marstacimab, first weekly sub-q option for hemophilia B. AJMC®. October 11, 2024. Accessed July 25, 2025. Https://www.Ajmc.Com/view/fda-approves-marstacimab-first-weekly-sub-q-option-for-hemophilia-b

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Revolutionizing Diagnosis: India's Affordable Test Kit For Hemophilia And Von Willebrand Disease

An innovative and affordable point-of-care test kit has been developed by the National Institute of Immunohaematology to diagnose genetic bleeding disorders like hemophilia A and Von Willebrand Disease in India. This new testing kit represents a significant shift from the existing costly and complex diagnostic procedures that are currently available only in a handful of tertiary facilities.

Dr. Rucha Patil, a scientist at the Mumbai-based institute, emphasized its importance due to the widespread underdiagnosis and limited healthcare access in India. The test, priced at just Rs 582, offers a more accessible alternative compared to lab-based procedures costing around Rs 2,086.

The initiative is also receiving international attention, with the World Federation for Hemophilia expressing interest. Its integration into India's primary health centers could vastly improve early detection and patient outcomes for the estimated 1.5 lakh people with hemophilia, of whom only 27,000 are currently diagnosed.

(With inputs from agencies.)

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