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.

Real-World Effectiveness of rFIXFc Prophylaxis in Patients with Haemophilia B Switched from Standard Half-Life Therapy in Three European Countries

“…Although this was not evaluated in the current study, previous real-world data have shown adherence to be an important consideration when physicians consider switching patients to rFIXFc [ 25 ], and that adherence rates improve after switching [ 17 , 19 ]. Other previously published real-world data have shown that rFIXFc may help to improve QoL, not only as consequence of a reduced treatment burden but also by reducing pain and improving activities of daily living [ 13 ].…”

“…Clinical trials evaluate drugs in an environment that controls for external ‘real-life’ factors and, as such, are limited by, for example, restrictions in the study population and mandated dose/treatment intervals. Data on the real-world effectiveness and usage of rFIXFc prophylaxis in a clinical setting are beneficial to add to the evidence from clinical trials in routine clinical practice, and a number of real-world evaluations of rFIXFc have been performed [ 13 – 20 ].…”

Recombinant factor IX Fc for the treatment of hemophilia B

“…51 Patients who switch to rFIXFc also experience improvements in quality of life, mood, activities of daily living, physical functioning, social functioning, and pain, which are limited in patients who remain on SHL therapy. 44,47 It is possible, although very rare, for inhibitor development to occur in a patient switching to rFIXFc prophylaxis, as reported in an isolated case study of an 82-year-old man with severe hemophilia B switching from SHL rFIX prophylaxis (see Supporting Information for further details). 57…”

“…1 Multiple papers have described outcomes among patients who switched to rFIXFc prophylaxis, with very consistent findings in clinical trials and in real-world clinical settings (Table S2). 11,[42][43][44][45][46][47][48][49][50][51][52][53][54][55][56] Typically, patients switching to rFIXFc prophylaxis experience reductions in injection frequency: the most common post-switch rFIXFc dose interval is 7 days, but intervals of 10 or 14 days are also seen. 11,42,43,45,46,[49][50][51][53][54][55][56] Factor consumption is also reduced after switching, generally by 26%-50%, to around 40-60 IU/kg/week.…”

“…Indeed, in a prospective registry study in Norway, >90% of patients receiving rFIXFc prophylaxis (median dose: 35 IU/kg once‐weekly) experienced zero bleeds during 3 years of follow‐up 51 . Patients who switch to rFIXFc also experience improvements in quality of life, mood, activities of daily living, physical functioning, social functioning, and pain, which are limited in patients who remain on SHL therapy 44,47 …”