What the trial was testing
The XTEND-KIDS enrolled 74 patients with hemophilia. The study was sponsored by Bioverativ, a Sanofi company 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
Sixty-four percent of kids had no bleeding episodes at all over the course of a year.
The New England journal of medicine · 2024 · NCT04759131
These findings — that no bleeding episodes for an entire year on weekly injections — were published in the The New England journal of medicine and represent the headline result of the study.
Researchers tracked outcomes across 74 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
If your child has severe hemophilia A, this once-a-week injection might mean far fewer bleeds and less time dealing with treatment. Most kids in this study didn't bleed at all. This treatment is FDA-approved and available now. Talk to your hematologist about whether it's right for your child.
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.