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HemophiliaMarch 2022Summary reviewed June 2026

A One-Time Gene Therapy Let Hemophilia Patients Make Their Own Clotting Factor

Researchers tested valoctocogene roxaparvovec, a one-time gene therapy, in 134 men with severe hemophilia A. After one year, patients made their own clotting factor and needed 99% less replacement treatment. Bleeding episodes dropped by 84%.

What the trial was testing

The GENER8-1 enrolled 144 patients with hemophilia. The study was sponsored by BioMarin Pharmaceutical and tracked outcomes across the full group of patients who matched the trial's eligibility profile.

It was a large trial designed to confirm whether the treatment works well enough for wider use. Trials at this stage are designed to produce evidence regulators and physicians can act on — not just observations to follow up later.

What the results showed

One year after gene therapy, patients needed 99% less clotting factor replacement.

The New England journal of medicine · 2022 · NCT03370913

These findings — that patients made their own factor VIII and barely needed infusions anymore — were published in the The New England journal of medicine and represent the headline result of the study.

Researchers tracked outcomes across 144 patients enrolled in the trial. The result was consistent enough across the group that the team felt confident reporting it.

What this means for patients

For patients with hemophilia, this result changes the calculus on what to ask their care team about. Whether it changes day-to-day care depends on factors like disease subtype, prior treatments, and where the patient is in their care journey.

What you can do now

This gene therapy was FDA-approved in June 2023 under the brand name Roctavian. It's designed for adults with severe hemophilia A who don't have antibodies against the virus used to deliver the therapy. Talk to your hemophilia treatment center about whether you're a candidate.

Eligibility for the treatments mentioned above depends on specific test results and clinical history. Bring this summary, the trial name, and your most recent labs or pathology report to your next visit.

Open hemophilia trials

RecruitingObservational study

ATHN Transcends: A Natural History Study of Non-Neoplastic Hematologic Disorders

In parallel with the growth of ATHN's clinical studies, the number of new therapies for all blood disorders is increasing significantly. Some of the recently FDA-approved therapies for congenital and acquired hematologic conditions have not yet demonstrated long-term safety and effectiveness beyond the pivotal trials that led to their approval. In addition, results from well controlled, pivotal studies often cannot be replicated once a therapy has been approved for general use.2,3,4,5 In 2019 alone, the FDA has issued approvals for 24 new therapies for congenital and acquired hematologic conditions.6 In addition, almost 10,000 new studies for hematologic diseases are currently registered on www.clinicaltrials.gov.7 With this increase in potential new therapies possible, it is imperative that clinicians and clinical researchers in the field of non-neoplastic hematology have a uniform, secure, unbiased, and enduring method to collect long-term safety and efficacy data. As emphasized in a recently published review, accurate, uniform and quality national data collection is critical in clinical research, particularly for longitudinal cohort studies covering a lifetime of biologic risk.8

Phoenix, Arizona, United States +24 more
RecruitingObservational study

World Bleeding Disorders Registry

The WBDR is an international observational disease registry of patients with hemophilia. It will provide a platform for a network of hemophilia treatment centres (HTCs) around the world to collect uniform and standardized patient data and guide clinical practice. With informed consent from the patient, the WBDR stores anonymous data about the person's disease, such as hemophilia type and severity, symptoms, and treatment.

Montreal, Quebec, Canada