Introduction: Real-world data are needed to evaluate treatment implementation, outcomes and costs of care in haemophilia patients switching prophylaxis from standard half-life (SHL) to extended half-life (EHL) clotting factor concentrates (CFCs).

Aim: We characterised treatment regimens, annual bleeding rate (ABR), adherence and costs in a nationwide Finnish haemophilia A (HA) and B (HB) cohort on prophylaxis, including non-switchers and switchers from SHL to EHL CFC.

Methods: This retrospective register study of adult patients with HA and HB was performed in University Hospitals during 2016-2021. Clinical and healthcare data were captured from electronic health records and national healthcare registers.

Results: Majority, 74% of HA and 71% of HB patients, switched from SHL to EHL. Thereafter, weekly mean infusions of CFC decreased (FVIII SHL 2.8, EHL 2.2; FIX SHL 1.6, EHL 0.9; p < 0.001). The mean annual consumption (international units, IU) increased by 18% from 219,534 per HA patient during SHL to 258,317 during EHL (p < 0.05) and declined per HB patient by 28% from 221,685 to 160,209 (p < 0.01). ABR appeared to decline after the switch in HA (mean SHL 2.8, EHL 0.9) and HB (SHL 1.6, EHL 0.8), while treatment adherence improved in HA from 81% to 95% (p < 0.01). The mean annual total costs of care in HA were €176,979 for SHL and €195,760 for EHL. In HB, the costs increased from €180,930 to €236,208 (p < 0.01).

Conclusions: Majority of patients on prophylaxis switched to EHL. The switch alleviated the infusion regimen, tended to lower bleeding rates and improved adherence with somewhat increased costs.