Results Compare With Findings in Adults
The results are similar to those reported among adults in the previous XTEND-1 phase 3 study, which was the basis for US Food and Drug Administration (FDA) approval of the drug in 2023 for routine prevention and on-demand treatment for the control of bleeding episodes, in addition to perioperative surgery for adults.
That approval was extended to children as well at the time, based on earlier interim results from the XTEND-Kids trial.
The annualized bleeding rate among adult patients treated with efanesoctocog alfa decreased from 2.96 to 0.69 over the 52 weeks, which was a significantly greater improvement compared with prestudy prophylaxis with conventional factor VIII prophylaxis (P < .001).
In children and adults alike, the decreased bleeding events were accompanied by improvements in physical health, pain, and joint health.
“Weekly prophylaxis with efanesoctocog alfa has the potential to provide long-term preservation of joint health,” the authors conclude.
Commenting in an editorial published concurrently with the study, Pratima Chowdary, MD, of the Katharine Dormandy Haemophilia and Thrombosis Centre, Royal Free Hospital, London, England, underscored the need for a longer duration of prophylaxis, particularly in children.
“In children, the factor VIII protein has a shorter half-life than in adults, and intravenous administration of coagulation factors is particularly challenging, owing to poor venous access,” she explains.
“In this context, a notable outcome in [the study] is the achievement of once-weekly prophylaxis in children with sustained factor VIII levels through the week, which augurs well for protection in the context of delayed or missed doses.”
Dr. Chowdary adds that limitations include that “the study participants had pre-existing tolerance of factor VIII, because only those with previous exposure to factor VIII and without inhibitors were eligible for enrollment.”
“As such, immunogenicity needs to be assessed in other patients, especially those with no previous treatment with factor VIII.”
Further commenting to this news organization, Dr. Chowdary emphasized “the key takeaway for patients with hemophilia is that the notion of a single, lifelong treatment is outdated.”
“Regular reviews and adjustments to prophylaxis are necessary to ensure optimal control of hemophilia, aiming for zero bleeds each year,” Dr. Chowdary noted.
Furthermore, “the treatment regimen to achieve this must also align with the life goals of both patients and their parents,” she said.
The study was supported by Sanofi and Sobi. The authors’ and Dr. Chowdary’s disclosures are published with the study and editorial, respectively.