Real‐World Assessment of rVIII‐SingleChain for Prophylactic Treatment in People With Severe Hemophilia A in High‐Resource Settings

INTRODUCTION: rVIII-SingleChain has been approved and reimbursed in Taiwan since September 2020 as prophylaxis for severe hemophilia A. AIM: This study compared real-world outcomes of prophylactic treatment with rVIII-SingleChain versus other long-acting FVIII products in people with severe hemophilia A (PwSHA) in Taiwan. METHODS: A retrospective de-identified patient chart-review-based study was conducted in three hemophilia treatment centers in Taiwan (September 2019-August 2021). Data of PwSHA who used rVIII-SingleChain or other long-acting FVIII products for prophylaxis (for ≥12 weeks following 1 September 2020) were included. Current treatment regimen, factor consumption, and bleeding events (annualized bleeding rate [ABR], annualized joint bleeding rate [AjBR], annualized spontaneous bleeding rate [AsBR]) data were collected from medical records. RESULTS: Overall, 39 patients were enrolled (rVIII-SingleChain: n = 14; other long-acting FVIII products: n = 25). Median (IQR) factor VIII consumption (IU/kg/week) was: 97.7 (92.3-103.2) for rVIII-SingleChain and 81.4 (71.0-90.3) for other long-acting FVIII products; 11/14 patients (78.6%) and 23/25 patients (92.0%), respectively, were dosed ≤2 times/week. Median (IQR) bleeding rates of rVIII-SingleChain versus other long-acting FVIII products were: ABR, 0.0 (0.0-9.8) vs 2.0 (0.0-5.0); AsBR, 0.0 (0.0-3.3) vs 1.0 (0.0-4.0); and AjBR, 0.0 (0.0-7.6) vs 0.0 (0.0-5.0). Half-life (hr) was comparable between O and non-O blood type patients for rVIII-SingleChain (mean ± SD: 15.3 ± 6.3 vs 17.8 ± 2.2; p = 0.1243) and rurioctocog alfa pegol (15.3 ± NA vs 17.6 ± 2.8; p = 0.3711); but significantly higher in non-O than O blood type for efmoroctocog alfa (20.6 ± 3.6 vs 14.6 ± 3.9; p = 0.0292). CONCLUSION: rVIII-SingleChain prophylactic treatment demonstrated effective bleeding control in PwSHA in Taiwan, with low dosing frequency (≤2 times/week) in most PwSHA.