Shanghai, China, September 17, 2026 — Belief BioMed (BBM), an innovative biotechnology company focused on developing cutting-edge gene therapies, today announced that the data from the clinical studies for BBM-H901 (generic name: Dalmacogene Ponparvovec) in adolescents with hemophilia B, a gene therapy drug developed and manufactured by Belief BioMed, have been published in the authoritative international journal Nature Medicine (Impact Factor:52.5). The paper is titled "Factor IX Padua AAV gene therapy in adolescents with hemophilia B：a phase 1 trial" ¹.

Background

Hemophilia B is an inherited bleeding disorder caused by mutations in the F9 gene, which encodes coagulation factor IX (FIX). By delivering a functional copy of the F9 gene to restore production of FIX with normal clotting activity, gene therapy represents the only treatment approach with the potential to cure the disease. Hemophilia B gene therapies that use a liver-targeted adeno-associated virus (AAV) vector to deliver the gene for a hyperactive FIX variant (FIX-Padua) have shown encouraging efficacy in clinical trials. Three hemophilia B gene therapies have been approved worldwide to date ^2-3, among which BBM-H901 is the first AAV-based hemophilia B gene therapy to be developed and manufactured in Asia, by Belief BioMed. In 2019, a team led by Professor Lei Zhang and Professor Renchi Yang at the Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, launched the first clinical study of the therapy in patients with hemophilia B, providing preliminary evidence of its efficacy and safety in Chinese patients. The findings were published in 2022 in The Lancet Haematology ³ and The New England Journal of Medicine ⁴. Subsequent Phase I/II and Phase III clinical trials further confirmed the favorable efficacy and safety profile of BBM-H901, supporting its marketing approval by China's National Medical Products Administration (NMPA) in April 2025. It became the first gene therapy for hemophilia approved in China, indicated for the treatment of adults with moderate to severe hemophilia B (congenital factor IX deficiency). The results were published in Nature Medicine in January 2026 ⁵. Yet for a long time, no data on gene therapy for hemophilia in children or adolescents under 18 had been reported internationally, leaving it unclear whether these patients could benefit from such treatment.

On September 16, 2026, teams led by Lei Zhang and Renchi Yang at the Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Qun Hu at Tongji Hospital affiliated to Tongji Medical College of Huazhong University of Science & Technology, and Xiao Xiao at Belief BioMed jointly published online in Nature Medicine the results of a clinical trial in adolescents with hemophilia B. The study provides preliminary evidence that BBM-H901 is safe and effective in adolescent patients with hemophilia B, rapidly increasing FIX activity and substantially reducing the annualized bleeding rate (ABR), thereby supporting the use of gene therapy in children and adolescents with hemophilia B.

This study was a multicenter, single-arm, open-label clinical trial that enrolled 11 participants, 3 in the 16–17 age group, 4 in the 14–15 age group, and 4 in the 12–13 age group, all of whom received a dose of 5×10¹² vg/kg. The primary objective was to evaluate the safety and efficacy of BBM-H901 in adolescent patients.

Results

Safety: The gene therapy demonstrated a favorable safety profile. One serious adverse event (SAE) and two grade 3 adverse events (AEs) were reported, all of which were considered unrelated to the study drug. No inhibitor development or thrombotic events were observed. The most common AEs included elevated white blood cell counts, elevated neutrophil counts, and rash, all of which were associated with the use of glucocorticoids. One participant developed abnormal liver function tests and recovered after intensified immunosuppressive therapy and liver-protective treatment.

Efficacy: At week 52 after treatment, mean FIX:C was 41.8 (SD 30.1) IU/dL (measured by one-stage assay; the same assay applies to all values reported below). Notably, mean FIX:C peaked at 67.1 (SD 23.1) IU/dL as early as day 6 after gene therapy, enabling patients to rapidly discontinue replacement therapy. The annualized bleeding rate (ABR) was 0.50 (95% CI: 0.1–2.9), a marked reduction from 13.9 (95% CI: 0.6–27.2) before treatment. The mean annualized number of factor IX concentrate infusions decreased from 77.7 (SD 32.0) before treatment to 1.45 (SD 2.46) after treatment. Joint bleeding was also significantly reduced, with the number of target joints falling to zero.

Conclusions

This study is the first gene therapy trial for hemophilia B in adolescents conducted internationally, and demonstrates that gene therapy with the hyperactive FIX variant (FIX-Padua) is likewise safe and effective in Chinese adolescent patients. The therapy acts rapidly, allowing patients to benefit quickly from gene therapy, and is expected to broaden the eligible population for hemophilia B gene therapy. Through early intervention during this critical window, it holds the promise of preventing disability if treated during adolescence, freeing patients from the burden of frequent infusions required by conventional therapy, and thereby delivering long-term benefits that extend from adolescence into old age and transforming patients' quality of life across their lifetime.

References

1.         Xue, F., Zhang, A., Ju, M. et al. Factor IX Padua AAV gene therapy in adolescents with hemophilia B: a phase 1 trial. Nat Med (2026). https://doi.org/10.1038/s41591-026-04636-8

2.         Coppens, M., et al. Etranacogene dezaparvovec gene therapy for haemophilia B (HOPE-B): 24-month post-hoc efficacy and safety data from a single-arm, multicentre, phase 3 trial. Lancet Haematol 11, e265-e275 (2024).

3.         Xue, F., et al. Safety and activity of an engineered, liver-tropic adeno-associated virus vector expressing a hyperactive Padua factor IX administered with prophylactic glucocorticoids in patients with haemophilia B: a single-centre, single-arm, phase 1, pilot trial. Lancet Haematol 9, e504-e513 (2022).

4.         Xue, F., et al. Total Knee Arthroplasty after Gene Therapy for Hemophilia B. N Engl J Med 387, 1622-1624 (2022).

5.         Xue, F., et al. Factor IX-Padua AAV gene therapy in hemophilia B: phases 1/2 and 3 trials. Nat Med 32, 93-102 (2026).

About Belief BioMed

Belief BioMed Inc. (BBM) is a global biotech company that integrates the research and development, manufacturing and clinical application of gene therapy products. The company is committed to providing innovative and more effective gene therapies for severe genetic and chronic diseases through safe and efficient viral vector technology. BBM has developed hundreds of key vector technologies, including HEK293 cell suspension serum-free culture process and full-scale chromatography purification process, and has established a commercial production platform for gene therapy drugs. The company has been building up its capabilities in a variety of fields including novel AAV capsids targeting different tissues, efficient transgene expression cassette design, and advanced clinically applicable vector manufacturing process. It has also established an extensive R&D pipeline covering a wide range of unmet clinical needs in different therapeutic areas such as hemophilia, DMD, Parkinson's disease, osteoarthritis, etc. Several product pipelines have entered clinical studies or submitted IND filings. The Biologics License Application (BLA) of a gene therapy for the treatment of adult patients with hemophilia B, has been approved by the NMPA of China.

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