Wolfgang Miesbach: First AAV Gene Therapy Data in Adolescents With Haemophilia B
Wolfgang Miesbach, Head of the Hemostasis and Hemophilia Center at Department of Medicine II, University Hospital Frankfurt, shared a post on LinkedIn about a recent article by Feng Xue at el., published in Nature Medicine, adding:
“A first AAV gene therapy for haemophilia B in adolescents. Xue and colleagues report in Nature Medicine a multicentre phase 1 trial of BBM-H901 (dalnacogene ponparvovec, FIX-Padua, AAV843) in 11 boys aged 12–18 with severe or moderately severe haemophilia B, at 5 × 10¹² vg/kg — the adult dose:
No dose-limiting toxicity. One SAE, unrelated to the vector; transaminitis in one participant, resolved under immunosuppression.
Mean FIX:C at week 52: 41.8 IU/dL (SynthASil) but 26.4 IU/dL (Actin FSL) – a reagent ratio of 1.49, a reminder that the assay shapes the message.
ABR 13.9 to 0.5; 82% bleed-free; no target joints at week 52.
The kinetics are the interesting part. Adolescents peaked higher than adults (106 vs 98 IU/dL) yet fell further by week 52 (42 vs 55 IU/dL). Nearly three-quarters dropped early, at weeks 2–4, and four lost expression durably.
Hepatocyte proliferation in a growing liver, diluting episomal vector, is the obvious explanation – but unproven, and the single-cell data point instead to immune activation on glucocorticoid withdrawal.”
Title: Factor IX Padua AAV gene therapy in adolescents with hemophilia B: a phase 1 trial
Authors: Feng Xue, Ai Zhang, Mankai Ju, Xia Wu, Bingqi Xu, Xiaolei Pei, Yuhua Wang, Wei Liu, Aiguo Liu, Wei Jiang, Xinyue Dai, Yunfei Chen, Xiaofan Liu, Rongfeng Fu, Ting Sun, Wenjing Gu, Jing Zheng, Zengmin Du, Caifeng Yang, Xiao Xiao, Renchi Yang, Qun Hu, Lei Zhang

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