Abstract 212: Andexanet Alfa, a Universal Antidote for Reversal of Anticoagulation of Factor Xa Inhibitors in Healthy Human Volunteers
Bibliographic record
Abstract
Introduction: Andexanet alfa (AnXa) is a recombinant modified fXa molecule that acts as a specific antidote for fXa inhibitors. We report clinical results in healthy subjects anticoagulated with apixaban (apix), rivaroxaban (riva), edoxaban (edox), or enoxaparin (enox), demonstrating rapid and sustained reversal of anticoagulation following administration of AnXa. Methods: These were Phase 2/3 randomized, double-blind, placebo-controlled studies in healthy subjects. In Phase 2, about153 subjects age18 - 45 were given one of the fXa inhibitors (apix 5 mg BID, riva 20 mg QD, edox 60 mg QD or enox 40 mg QD) for 6 days. AnXa or placebo (3:1 randomization) was given IV on Day 6, 3hrs after the last inhibitor dose (∼inhibitor Cmax). Safety was followed through Day 48. A range of AnXa doses (bolus or bolus+infusion) was evaluated by correction of biomarkers (anti-fXa activity, free inhibitor concentrations and thrombin generation (TG)). In Phase 3 (ANNEXA™), older subjects age 50 to 75 were dosed with apix (5 mg BID) or riva (20 mg QD) for 4 days. ANNEXA™-A had 63 subjects treated with apix. AnXa (400 mg bolus; 400 mg bolus plus 4 mg/min x 2hr infusion) or placebo (3:1 randomization) was given on Day 4, 3 hrs after the last apix dose. ANNEXA™-R had 82 subjects treated with riva. AnXa (800 mg bolus; 800 mg bolus plus 8 mg/min x 2hr infusion) or placebo (2:1) was given on Day 4, 4 hrs after the last riva dose. Safety was followed through Day 43. Results: About 298 healthy subjects were enrolled in the studies. AnXa demonstrated rapid and sustained reversal of both direct and indirect fXa inhibitors as measured by correction of biomarkers. The ANNEXA™ studies confirmed findings from Phase 2, and met all primary (reversal of anti-fXa) and secondary endpoints (reduction of free inhibitor concentration and restoration of TG) with high statistical significance. AnXa was well-tolerated with no serious adverse events, thrombotic events, or antibodies to fX or fXa reported. Conclusion: AnXa treatment results in rapid and sustained reversal of anticoagulation of fXa inhibitors. A Phase 3b/4 confirmatory study (ANNEXA-4) in patients with acute major bleeds is ongoing.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.010 | 0.002 |
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".