Long-term Outcomes With Efanesoctocog Alfa Prophylaxis for Previously Treated Children With Severe Hemophilia A, an Interim Analysis of the Phase 3 XTEND-ed Study
Bibliographic record
Abstract
Introduction: Efanesoctocog alfa (formerly BIVV001) is a first-in-class high-sustained factor VIII (FVIII) replacement therapy designed to overcome the von Willebrand factor–imposed half-life ceiling. Once-weekly efanesoctocog alfa 50 IU/kg was well tolerated and provided highly effective bleed protection and factor activity within normal to near-normal levels (>40%) for 3 days, and of ~10% at Day 7, in children with severe hemophilia A in the XTEND-Kids study (NCT04759131). The aim is to evaluate long-term data on safety and efficacy of efanesoctocog alfa in previously treated children with severe hemophilia A in the XTEND-ed study (NCT04644575). Method: XTEND-ed is a multicenter, open-label study that enrolled participants from previous Phase 3 studies, including children<12 years of age who received weekly efanesoctocog alfa prophylaxis for≤52 weeks in XTEND-Kids, and continue weekly 50 IU/kg prophylaxis in XTEND-ed. The primary endpoint is the occurrence of FVIII inhibitors. Secondary endpoints include annualized bleed rates (ABRs), efficacy for bleed treatment, and safety. Participants provided informed consent and XTEND-ed was approved by applicable ethics committees. First Interim Analysis Data cut: June 8, 2023. Results: Seventy-one of 74 males (96%) rolled over from XTEND-Kids to XTEND-ed. The mean (standard deviation [SD]) efficacy period was 35.8 (14.1) weeks. No FVIII inhibitors were detected. The mean (SD) ABR was 0.70 (1.27; 6-monthly data: [ Fig. 1 ]), thus maintaining the low mean ABR observed in the parent study (0.88). Most bleeds (86%; 30/35) resolved with a single dose of efanesoctocog alfa 50 IU/kg, with 96% (23/24) of hemostatic responses rated as excellent or good. Overall, 43 (61%) participants experienced≥1 treatment-emergent adverse event (TEAE) and 2 (3%) experienced≥1 serious TEAE ([ Fig. 2 ]). Fig. 1
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.004 | 0.003 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.002 | 0.004 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".