Physical activity and bleeding outcomes among people with severe hemophilia on extended half‐life or conventional recombinant factors

BACKGROUND: Few have assessed physical activity (PA) and annual bleed rates (ABRs) among people with hemophilia on extended half‐life (EHL) factors (recombinant factor VIII Fc [rFVIIIFc]/recombinant factor IX Fc [rFIXFc]) and conventional factors (recombinant factor VIII [rFVIII]/recombinant factor IX [rFIX]). OBJECTIVE: To assess changes in PA and ABR at consecutive annual visits in individuals with severe hemophilia A and B (HA/HB) on prophylactic treatment with rFVIIIFc/rFIXFc versus rFVIII/rFIX. PATIENTS/METHODS: We conducted a retrospective chart review of 344 people with severe HA/HB (ages 6‐35) receiving prophylaxis with rFVIIIFc/rFIXFc (EHL factors) or rFVIII/rFIX (conventional factors) for ≥6 months in 2014‐2015. Differences in changes in outcomes from 2014 to 2015 were compared across the treatment groups. RESULTS: Baseline characteristics and adherence to the prophylactic regimen were similar across the treatment groups. Greater increase in weekly PA frequency and duration were observed among all EHL groups, except for children treated with rFIXFc. The increase in PA frequency was greater among the children on rFVIIIFc group, adults on rFVIIIFc group, and adults on rFIXFc group by 1.2, 1.2, and 1.4 events/week, respectively, compared to their rFVIII/rFIX counterparts. The increases in PA duration were 44, 60, and 80 min/wk greater among the children on rFVIIIFc, adults on rFVIIIFc, and adults on rFIXFc groups, respectively. Larger reductions in total ABR were observed in children and adults treated with rFVIIIFc compared to rFVIII (0.4 and 0.7 fewer bleeds). Larger reductions were also observed in spontaneous ABR in adult rFVIIIFc and rFIXFc groups (0.8 and 0.3 fewer bleeds, respectively). CONCLUSIONS: This study suggests that rFVIIIFc/FIXFc agents can positively impact PA while maintaining low ABRs.