First Interim Analysis of Clinical Outcomes in Adults and Adolescents With Severe Hemophilia A Receiving Efanesoctocog Alfa Prophylaxis in XTEND-ed, a Phase 3 Long-term Extension Study
Bibliographic record
Abstract
Introduction: Efanesoctocog alfa (formerly BIVV001) is a first-in-class high-sustained factor VIII (FVIII) replacement therapy designed to decouple FVIII from endogenous von Willebrand factor. In the Phase 3 XTEND-1 study (NCT04161495), once-weekly efanesoctocog alfa demonstrated superior bleed protection over prior prophylaxis, was well tolerated, and provided FVIII activity within the normal to near-normal (>40%) range for most of the week. The aim is to evaluate long-term safety and efficacy of efanesoctocog alfa in adults/adolescents with severe hemophilia A from XTEND-ed (NCT04644575). Method: Previously treated patients (≥12 years old) who completed XTEND-1 (Arm A/B) could continue once-weekly efanesoctocog alfa (50 IU/kg) prophylaxis in the multicenter, open-label, long-term XTEND-ed study. The primary endpoint is incidence of FVIII inhibitor development. Secondary endpoints include annualized bleed rates (ABRs), efficacy for bleed treatment, and safety. XTEND-ed was approved by local ethics committees; participants provided informed consent. First interim analysis data cut: June 8, 2023. Results: A total of 146 patients (including 1 female) rolled over from XTEND-1 to XTEND-ed (12–17 years, n=21; 18–64 years, n=120;≥65 years, n=5). Mean (range) treatment duration in XTEND-ed was 82.5 (14.1–103.6) weeks. FVIII inhibitors were not detected. Mean (standard deviation) ABR during XTEND-ed for patients from XTEND-1 Arms A and B was 0.72 (1.26) and 0.42 (0.89), respectively (6-monthly data: [ Fig. 1 ]), thus maintaining the low mean ABRs observed in the parent study (Arm A: 0.71; Arm B: 0.69). Most (94%; 142/151) bleeding episodes resolved with 1 injection of efanesoctocog alfa; response was rated by participants as excellent/good for 88% (108/123) of bleeds. Overall, 108 (74%) participants experienced≥1 treatment-emergent adverse event (TEAE) and 17 (12%) 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) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.003 | 0.004 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.003 |
| Insufficient payload (model declined to judge) | 0.004 | 0.001 |
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".