What the trial was testing
The trial enrolled 15 patients with hemophilia. The study was sponsored by Pfizer and tracked outcomes across the full group of patients who matched the trial's eligibility profile.
It was initial testing (phase 2). 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
The annual bleeding rate dropped from 11 episodes per year to less than 1 after gene therapy.
The New England journal of medicine · 2017 · NCT02484092
These findings — that nine patients had no bleeding episodes after receiving the one-time gene therapy treatment — were published in the The New England journal of medicine and represent the headline result of the study.
Researchers tracked outcomes across 15 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 was an initial testing study with 10 patients. The gene therapy (fidanacogene elaparvovec) later received FDA approval in 2024 under the brand name Beqvez for adults with moderate to severe hemophilia B. Ask your doctor if this treatment might be right for you.
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
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
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.