Abstract Number: LB 01.4
Meeting: ISTH 2022 Congress
Theme: Hemophilia and Rare Bleeding Disorders » Hemophilia - Clinical
Background: Efanesoctocog alfa is a new class of factor VIII (FVIII) replacement designed to overcome the von Willebrand factor-imposed half-life ceiling.
Aims: To evaluate the efficacy, safety, and pharmacokinetics of efanesoctocog alfa in previously treated patients, ≥12 years, with severe hemophilia A.
Methods: After informed consent, patients on prior FVIII prophylaxis entered Arm A (52 weeks once-weekly intravenous efanesoctocog alfa prophylaxis [50 IU/kg]) (NCT04161495). Patients receiving prior on-demand therapy entered Arm B (26 weeks on-demand efanesoctocog alfa [50 IU/kg], then 26 weeks once-weekly prophylaxis [50 IU/kg]). A subset had enrolled in a 12-month observational pre-study. Primary endpoint was Arm A annualized bleed rate (ABR). Secondary endpoints included observational pre-study versus on-study intra-patient ABR (key secondary), bleed treatment, physical health, pain, joint health, pharmacokinetics, and safety.
Results: One female and 132 males enrolled in Arm A; 26 males in Arm B. Arm A mean (SD) and median (IQR) ABR were 0.71 (1.43) and 0.00 (0.00–1.04), respectively. Intra-patient ABR comparison demonstrated superior bleed protection with efanesoctocog alfa versus prior FVIII prophylaxis (P< 0.001; Figure). Most bleeds (96.7%) resolved with one efanesoctocog alfa injection, and 94.9% of responses were rated excellent/good. Once-weekly efanesoctocog alfa provided high sustained factor activity (Figure) consistent with earlier studies. Efanesoctocog alfa prophylaxis was associated with significant improvements from baseline in physical health (P=0.0001), pain (P=0.0276), and joint health (P=0.0101) at Week 52 (Table). Inhibitor development to FVIII was not detected. The most common treatment-emergent adverse events ( >5% of participants overall) were headache, arthralgia, fall, and back pain.
Conclusion(s): Once-weekly efanesoctocog alfa prophylaxis was well-tolerated, provided superior bleed protection to prior prophylaxis, and showed clinically meaningful improvements in physical health, pain, and joint health. Efanesoctocog alfa prophylaxis provided high sustained factor activity within normal to near-normal levels ( >40%) for most of the week and >10% at Day 7.
Funding: Sanofi and Sobi.
To cite this abstract in AMA style:
von Drygalski A, Chowdary P, Kulkarni R, Susen S, Konkle B, Oldenburg J, Matino D, Klamroth R, Weyand A, Jimenez Yuste V, Nogami K, Poloskey S, Winding B, Willemze A, Knobe K. Efficacy, Safety, and Pharmacokinetics of Once-Weekly Efanesoctocog Alfa (BIVV001) Prophylaxis in Previously Treated Patients With Severe Hemophilia A: Results From the Phase 3 XTEND-1 Study [abstract]. https://abstracts.isth.org/abstract/efficacy-safety-and-pharmacokinetics-of-once-weekly-efanesoctocog-alfa-bivv001-prophylaxis-in-previously-treated-patients-with-severe-hemophilia-a-results-from-the-phase-3-xtend-1-study/. Accessed March 21, 2024.« Back to ISTH 2022 Congress
ISTH Congress Abstracts - https://abstracts.isth.org/abstract/efficacy-safety-and-pharmacokinetics-of-once-weekly-efanesoctocog-alfa-bivv001-prophylaxis-in-previously-treated-patients-with-severe-hemophilia-a-results-from-the-phase-3-xtend-1-study/