What the trial was testing
The trial enrolled 10 patients with hemophilia. The study was sponsored by CSL Behring and tracked outcomes across the full group of patients who matched the trial's eligibility profile.
It was an early-stage trial — researchers are still confirming safety and getting an early look at how well the treatment works. 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
Spontaneous bleeding dropped by up to 70% after a single gene therapy treatment.
Blood · 2018 · NCT02396342
These findings — that patients in the higher-dose group had 70% fewer spontaneous bleeding episodes after treatment. — were published in the Blood and represent the headline result of the study.
Researchers tracked outcomes across 10 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 early-stage study with 10 patients and the treatment is not yet FDA-approved. The results were promising, but gene therapy for hemophilia B is still being studied. If you have hemophilia B, ask your doctor about open clinical trials or other approved treatment options.
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
Study to Provide Continued Access to Treatment for Patients Completing a Previous Trial With Efanesoctocog Alfa
This is a multinational, prospective, open-label, roll-over study in patients with haemophilia A, ≥6 years of age, who have completed participation in any of the parental studies with efanesoctocog alfa; XTEND-ed study (LTS16294), FREEDOM study (Sobi.BIVV001-001), PK comparison study (Sobi.BIVV001-003) or SHINE study (Sobi.BIVV001-004). The aim of the study is to provide patients with continuous benefit from efanesoctocog alfa treatment and to further continue clinical monitoring for safety and efficacy until efanesoctocog alfa is commercially available in each patient's respective country (or until March 2027, whichever comes first). The study starts with the Baseline Visit, which will be done in connection to the end of treatment at the EoT/EoS visit (or equivalent) in the respective parent study. Subsequent study visits (on site or phone call) will be done approximately every 13 weeks until End of Treatment. An End of Study safety phone call will be done 14 (+7) days after the End of Treatment Visit.
Phase 3 Clinical Project of Pegylated Recombinant Human Coagulation Factor VIII-Fc Fusion Protein
To evaluate the prophylactic efficacy of recombinant human coagulation factor Ⅷ-Fc fusion protein (FRSW117) for injection in patients with severe hemophilia A. To evaluate the safety of recombinant human coagulation factor Ⅷ-Fc fusion protein (FRSW117) for injection in patients with severe hemophilia A. Secondary purpose: To evaluate the efficacy of recombinant human coagulation factor Ⅷ-Fc fusion protein for injection (FRSW117) in hemostasis and surgical hemostasis in patients with severe hemophilia A. To evaluate the pharmacokinetic (PK) characteristics of recombinant human coagulation factor Ⅷ-Fc fusion protein (FRSW117) for injection in treated patients with severe hemophilia A. To evaluate the immunogenicity of recombinant human coagulation factor Ⅷ-Fc fusion protein (FRSW117) for injection in treated patients with severe hemophilia A.