Effectiveness and Safety Outcomes in Patients with Hemophilia a Receiving Antihemophilic Factor (Recombinant) for at Least 5 Years in a Real-World Setting: 6-Year Interim Analysis of the Ahead International and German Studies

Introduction: Long-term effectiveness and safety data in patients treated in routine clinical practice settings can be captured from real-world studies. The international (INT) and German (GER) Antihemophilic factor (recombinant; rAHF) Hemophilia A (HA) outcome Database (AHEAD) studies assess long-term effectiveness and safety outcomes in patients with moderate HA (factor VIII level 1–5%) or severe HA (factor VIII <1%) receiving rAHF (ADVATE^®; Baxalta US Inc., a Takeda company, Lexington, MA, USA) in routine clinical practice.

Methods: These are non-interventional, prospective, long-term, multicenter studies (INT: NCT02078427; GER: DRKS 00000556). Key outcomes include Gilbert scores (primary endpoint; pain scored 0–3; bleeding scored 0–3, and physical exam scored 0–12), annualized bleeding rates (ABRs) by disease severity, and adverse events (AEs). Findings reported here are from the 6-year interim analysis (data cut-off: July 15, 2019), and focus on patients who have received rAHF prophylaxis or on-demand (OD) treatment for ≥5 years in the studies. All data are reported for the safety analysis set (SAS), which comprised patients who passed screening and were assigned to a treatment group or regimen in the INT study, or were enrolled and have received ≥1 dose of rAHF since study enrollment in the GER study.

Results: At the time of analysis, the INT study SAS comprised 707 patients, 156 of whom had received ≥5 years of rAHF treatment during the study. The GER study SAS comprised 382 patients, 231 of whom had received ≥5 years of rAHF treatment. Average Gilbert scores (all joints) were consistently low (years 1–6: median 0–1.0; mean 0–1.3) for both children aged 2 to <12 years and adolescents aged 12 to <18 years receiving rAHF prophylaxis within both studies. In the INT study, average Gilbert scores were lower with prophylaxis than with OD therapy in adults (aged ≥18 years) throughout the observation period (years 1–6: median: 0.9–1.4 [n=8–25] vs 1.4–6.3 [n=2–8], respectively; mean: 1.4–2.2 vs 2.1–6.3; respectively); significant differences (P<0.05) between mean values were observed for years 3, 4, and 6. In the GER study, average Gilbert scores were slightly higher with prophylaxis than with OD in adults (years 1–6: median: 0.7–2.2 [n=12–37] vs 0.3–1.4 [n=2–15], respectively; mean: 1.0–2.7 vs 0.5–2.2, respectively; P-values not available). In the INT study, ABRs were consistently lower in patients receiving rAHF prophylaxis than in those receiving rAHF OD, irrespective of disease severity (Table). A similar trend was observed in the GER study in patients with severe HA, whereas ABRs were similar for both treatment regimens in patients with moderate HA. In both studies, greater proportions of patients with moderate or severe HA receiving rAHF prophylaxis had 0 bleeds than those receiving rAHF OD (Table). In the INT study, 842 AEs were reported in 116/156 (74.4%) patients, including 2 treatment-related serious AEs in 2 (1.3%) patients. In the GER study, 1321 AEs were reported in 197/231 (85.3%) patients, including 29 treatment-related serious AEs in 14 (6.1%) patients.

Conclusions: These findings in patients receiving rAHF for ≥5 years in a real-world setting corroborate previous data on the long-term efficacy and tolerability of rAHF in patients with moderate or severe HA. rAHF demonstrated effectiveness in maintaining joint health (as measured by Gilbert scores) in adult patients.