What the trial was testing
The EXPLORER4/EXPLORER5 enrolled 36 patients with hemophilia. The study was sponsored by Novo Nordisk A/S 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
Patients on the daily injection had an estimated 3 to 7 bleeding episodes per year, down from their usual rates.
Blood · 2019 · NCT03196297
These findings — that far fewer bleeds than patients usually experience without daily prevention — were published in the Blood and represent the headline result of the study.
Researchers tracked outcomes across 36 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 treatment is still in mid-stage testing and not yet FDA-approved. If you have hemophilia and struggle with frequent bleeds despite current treatments, ask your doctor whether there are open trials for this injection or similar options. The results were strong enough that all participants chose to keep using it in the extended study.
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
The Efficacy and Safety of ZS801 in Chinese Hemophilia B Patients.
A non-randomized, open-label study to evaluate the safety, kinetics and efficacy of a single intravenous infusion of ZS801 in hemophilia B subjects with endogenous FIX ≤2%.
Tight Control of Treatment Adherence and Efficacy by Telemedicine for an Improved Personalized Management of Patients With Hemophilia
In patients with haemophilia, close monitoring of bleeding with optimal adherence to treatment, a personalised treatment programme and the possibility of early diagnosis of haemarthrosis are essential. The TEMPO project will help advance the state of the art in optimal adherence, rigorous monitoring, and accurate and early diagnosis and management of haemarthrosis by collecting and integrating big data in order to personalise the treatment regimen for each patient, as envisaged by the current model of personalised medicine.