Insight

Aug 25, 2025, 14:53

Wolfgang Miesbach: New Study on AAV5 Antibodies in Haemophilia B Gene Therapy

Wolfgang Miesbach, Head of the Department of Haemostaseology and the Haemophilia Center of Medical Clinic 2 and Professor of Medicine at Frankfurt University Hospital, shared a post on LinkedIn:

“New study on AAV5 antibodies in haemophilia B gene therapy. We just published in Molecular Therapy – Methods and Clinical Development on how AAV5 antibodies behave over time in adults with haemophilia B.
This analysis is based on the HOPE-B phase 3 trial with 67 patients in the US and Europe.

Importantly, for etranocogene dezaparvovec, AAV5 NAb positivity is not a strict contraindication. But very high titers may reduce transduction efficiency. That’s why NAb screening is an essential part of assessing eligibility for commercial gene therapy.

Key findings:

48% of patients had neutralizing antibodies (NAbs) at screening (median titer 58; range 9–3440)
Levels remained stable over 8 months (median variation 25%; range 2–154%)
Strong correlation between NAbs and IgG (r=0.96)
Fewer than 5% switched from negative to positive
~10% seroreverted from positive to negative

NAb positivity was more frequent in patients ≥50 years (p=0.0065)

Why this matters?
NAb test results were consistent over months. Screening can be done up to 8 months before gene therapy infusion, giving more flexibility for clinical planning.

Thanks to Robert Klamroth and Sandra Le Quellec for leading this work, and to CSL for supporting the study.”

Title: Natural history of preexisting AAV5 antibodies in adults with hemophilia B during the lead-in of the etranacogene dezaparvovec phase 3 study

Authors: Robert Klamroth, Michael Recht, Nigel S. Key, Wolfgang Miesbach, Steven W. Pipe, Radoslaw Kaczmarek, Douglass Drelich, Blanca Salazar, Sandra Le Quellec, Paul E. Monahan, Nicholas Galante, Paul van der Valk, Jacqueline Tarrant

Read the Full Article.

Wolfgang Miesbach

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Blanca Salazar Douglass Drelich Jacqueline Tarrant Michael Recht Nicholas Galante Nigel S. Key Paul E. Monahan Paul van der Valk Radoslaw Kaczmarek Robert Klamroth Sandra Le Quellec Steven W. Pipe Wolfgang Miesbach

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