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BAY 81-8973 Demonstrates Long-Term Safety and Efficacy in Children With Severe Haemophilia A: Results From the LEOPOLD Kids Extension Study

Ljung R, Chan AKC, Ahuja SP, Mancuso ME, Marquez JFC, Volk F, Blanchette V, Kerlin BA et al.

European journal of haematology, 2025

82 participants

Abstract

Objectives: To report the long-term safety and efficacy of BAY 81-8973 in the LEOPOLD Kids extension phase.

Methods: Patients received BAY 81-8973 (25-50 IU/kg) at least twice weekly. The primary endpoint was safety, assessed in all patients who entered the extension phase (n = 82). Efficacy endpoints were assessed in patients without high-titre inhibitors/immune tolerance induction (n = 67).

Results: Children (n = 82) received BAY 81-8973 for a median of 3.1 years per patient and a median of 405 exposure days per patient. Long-term BAY 81-8973 treatment was well tolerated, with no cases of de novo inhibitor development in the extension phase. Annualised bleeding rates (ABRs) within 48 h of prophylaxis were low for all bleeds (median [IQR], 0.7 [0-1.9]; mean, 1.4 [SD, 2.1]) and for joint bleeds (median [IQR], 0 [0-0.7]; mean, 0.5 [SD, 1.1]) (n = 67). Twenty-one of 67 patients (31.3%) had zero bleeds within 48 h of prophylaxis; the treatment response was 'good'/'excellent' in 87.9% of bleeds, and most bleeds resolved with ≤ 2 BAY 81-8973 infusions (83.5%).

Conclusion: Long-term BAY 81-8973 treatment is well tolerated and maintains low ABRs for all bleeds and joint bleeds in children with severe haemophilia A.

Trial registration: ClinicalTrials.gov identifier: NCT01311648.

How strong is the evidence?

Evidence Hub reads this as a clinical trial, done in people. Its evidence level is 3 of 5 (Moderate · trial / cohort / secondary analysis). Trials without a large randomized design, cohorts and secondary analyses give moderate evidence. Reported size: 82 participants or records.

How the five levels of evidence work. The level is assigned automatically from the abstract and can be wrong, so check the paper.

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