Gene therapy for hemophilia b shows promise in Long-Term study

NCT ID NCT05360706

First seen Jun 24, 2026 · Last updated Jun 27, 2026 · Updated 2 times

Summary

This study follows 9 adults with severe or moderately severe hemophilia B who received a one-time gene therapy (AAV5-hFIX) to help their bodies produce clotting factor IX. Researchers are checking if the treatment remains safe and effective for up to 10 years after the initial dose. The goal is to see if this gene therapy can reduce or prevent bleeding episodes over the long term.

What this could mean

Our plain-language read of the trial. This is informational only — not medical advice or a prediction.

Active substance

gene therapy (AAV5-hFIX) to produce clotting factor IX

What this could lead to

If successful, this could show that a single gene therapy treatment provides long-lasting control of bleeding episodes, reducing or eliminating the need for regular factor IX infusions.

What could go wrong

This is a small extension study with only 9 participants, so results may not apply to everyone. Long-term safety concerns, such as liver effects or loss of effectiveness over time, are still being monitored.

Disclaimer Read more

This is a summary of the original study . Summaries may miss details or leave out important information. Before applying or accepting participation, make sure you have read and understood the full study. Curemydisease.com takes no responsibility whatsoever for anything missed, misunderstood, or acted upon as a result of our summary — we know it does not capture everything.

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Conditions

The condition(s) this trial relates to.

hemophilia B

As listed by the trial registrant

The condition terms exactly as the trial's registrant entered them.

Contacts and locations

Locations

  • Amsterdam UMC - Locatie AMC

    Amsterdam, Netherlands

  • Erasmus MC

    Rotterdam, Netherlands

  • Groningen UMC

    Groningen, Netherlands

  • Universitaetsklinikum Frankfurt - Klinikum der Johann Wolfgang Goethe Universitae

    Frankfurt, Germany

  • Universitair Medisch Centrum Utrecht

    Utrecht, Netherlands

  • Vivantes Klinikum im Friedrichshain

    Berlin, Germany