PB0687 - Real-world efficacy of extended half-life Factor VIII in patients with haemophilia A on prophylaxis

Background: Standard half-life Factor VIII (FVIII) products were previously the standard of care as prophylaxis in Haemophilia A with requiring alternate day administration. Recently, extended half-life (EHL) FVIII has been licensed to improve adherence and convenience for patients. Two products available in the United Kingdom are 1. Esperoct (turoctocog alfa pegol), a PEGylated recombinant FVIII, and 2. Elocta (efmoroctocog alfa), a rFVIII-Fc fusion protein. While the ASPIRE trial (Elocta) and Pathfinder (Esperoct) trial demonstrated ABR of < 1 and 1.2 respectively, evidence in the real-world setting are useful to validate the findings.

Aims: To review the management, real-world outcomes and concordance of patients receiving EHL FVIII outside of the clinical trial setting.

Methods: A single centre, retrospective audit of clinical notes and laboratory results for all patients (children and adults) currently receiving EHL FVIII. Data were collected on patient demographics, annualised bleed rates (ABR), surgery and the presence of FVIII inhibitors.

Results: 44 patients are on EHL FVIII at St Thomas’ Hospital Haemophilia comprehensive care centre, which treats a total of 370 patients with Haemophilia A of any severity. 18 patients use Esperoct and 26 use Elocta with an average age of 41.5 years and 21 years respectively. Treatment time on Esperoct was 25 months (stdev 25.8) and Elocta 45.2 months (stdev 25.9), with the majority infusing twice weekly. The ABR for Esperoct was 1.2 and for Elocta 0.92. Major and minor surgical procedures were performed with no bleeding. Pharmacokinetic studies have been difficult during the pandemic but 14/18 (77.8%) troughs were done with Esperoct and 26/26 with Elocta. No inhibitors were identified with either EHL FVIII.

Conclusion(s): In a large cohort, EHL FVIII have demonstrated good efficacy data at minimising ABRs in the real-world setting, providing adequate haemostasis during surgical procedures whilst reducing the infusional burden for patients.