Recombinant factor IX‐Fc fusion protein in severe hemophilia B: Patient‐reported outcomes and health‐related quality of life

Abstract Introduction In 2017, all people with severe hemophilia B in Ireland switched to recombinant factor IX Fc fusion protein concentrate (rFIXFc) prophylaxis. Patient‐reported outcomes (PROs) and health‐related quality of life (HRQoL) are important to evaluate with new treatments. Aims To assess HRQoL in people with severe hemophilia B and their experience after switching to rFIXFc prophylaxis. Methods Participants completed a Patient Reported Outcomes Burden and Experience (PROBE) questionnaire on initiation and following two years of rFIXFc prophylaxis. The PROBE questionnaire has four domains: demographics, general health, haemophilia‐specific, and European Quality of Life 5‐Dimensions (EQ‐5D‐5L) questionnaire. Results Twenty‐three participants completed the questionnaire at both time points. The number of activities where chronic pain occurred and interfered with the activity was reduced by 25% and 33%, respectively (P < .001), following two years of rFIXFc prophylaxis. There was a 9% decrease in chronic pain during the second year of rFIXFc prophylaxis compared to baseline, but the rate remained high, at 74%. A 25% reduction in the number of affected activities of daily living (ADLs) was reported following 2 years of rFIXFc prophylaxis (P = .007). The most common health problems were arthritis, hypertension, anxiety/depression, and gingivitis. The median EQ‐5D‐5L score was similar following two years of rFIXFc prophylaxis, 0.76 (range, −0.01 to 0.95), compared to 0.77 (range, 0.36‐1) at baseline. Conclusion This study of real‐world patient experience using PROs demonstrates a reduction in chronic pain and improvement in ADLs in participants after switching to rFIXFc prophylaxis. It provides important insights into patient‐identified health care needs and living with severe hemophilia B