BAY 81‐8973 demonstrated efficacy, safety and joint status improvement in patients with severe haemophilia A in the LEOPOLD I extension for ≤2 years

Objectives BAY 81‐8973 (Kovaltry®), a full‐length, unmodified, recombinant human factor VIII, provided excellent bleeding control for patients with haemophilia A in the pivotal 1‐year LEOPOLD I trial. The LEOPOLD I extension evaluated long‐term efficacy and safety of BAY 81‐8973 prophylaxis. Methods After completing LEOPOLD I, patients continued receiving 20‒50 IU/kg BAY 81‐8973 two‐ or three‐times weekly in the extension. Outcomes included annualised bleeding rate (ABR) and haemostasis during surgery. Results Fifty‐five patients aged 12‐65 years participated in the extension. Median (range) exposure days during the 2‐year total study period was 309 (115‐355). No patient switched regimens. Median (Q1; Q3) ABR for all bleeds was 2.0 (1.0; 6.1) during the pivotal study, 2.0 (0.0; 5.2) during the extension, and 2.0 (0.5; 5.5) combined. The proportion of joint bleeds affecting target joints decreased (pivotal study: 90.9%, extension: 60.0%). Haemostasis was assessed as excellent/good in all five major surgeries. One serious adverse event (myocardial infarction) occurred in a patient with cardiovascular risk factors. No patients developed inhibitors. Conclusions BAY 81‐8973 prophylaxis efficacy outcomes in the pivotal study were maintained or, in the case of joint protection, improved during the extension, with a safety and tolerability profile consistent with previous experience.