The Safety and Efficacy of Full Versus Reduced Dose Betrixaban in the Acute Medically Ill VTE (Venous Thromboembolism) Prevention with Extended Duration Betrixaban (APEX) Trial
Bibliographic record
Abstract
Abstract Background: The exposure of all the currently licenced DOACs is increased in renal impairment and by certain drug interactions. The Acute Medically Ill VTE (Venous Thromboembolism) Prevention with Extended Duration Betrixaban (APEX) trial assessed the safety and efficacy of extended-duration thromboprophylaxis using betrixaban versus standard dosing of enoxaparin among acutely ill medical patients. The full 80 mg dose of betrixaban was halved to 40 mg among subjects with severe renal insufficiency (calculated creatinine clearance <30ml/min), or receiving a concomitant strong P-glycoprotein (P-gp) inhibitor. Objectives and Methods: The goal of this analysis is to assess the efficacy and safety of full (80 mg) and reduced dose (40 mg) betrixaban relative to enoxaparin in the APEX trial. Subjects were stratified into the two dose groups prior to randomization according to the pre-specified dosing criteria. The primary efficacy outcome was the composite of asymptomatic proximal and symptomatic venous thromboembolism (proximal or distal deep-vein thrombosis, symptomatic nonfatal pulmonary embolism, or death from venous thromboembolism). The principal safety outcome was major bleeding. Results: The median concentration of betrixaban among subjects administered the 80 mg dose was higher than that of the 40 mg dose (19 ng/ml vs 11 ng/ml, p<0.0001). In the primary analysis Cohort 1 (the elevated D-dimer +ve patients), the primary efficacy outcome was significantly reduced among subjects treated with 80 mg of extended dose betrixaban vs enoxaparin [6.3% (95/1516) vs 8.4% (130/1549), RRR = 0.26 (0.04-0.42), p=0.023]. A similar reduction was observed in the entire modified Intention to Treat (mITT) population [4.87% (122/2506) vs 7.06% (181/2562), RRR = 0.30 (0.13 - 0.44), p=0.001]. In contrast, among subjects receiving 40 mg of betrixaban there was no significant difference in the primary outcomes compared with enoxaparin across Cohorts 1, 2, and 3. There was no excess of major bleeding associated with administration of either the full 80 mg dose or the reduced 40 mg dose of betrixaban as compared with enoxaparin. Conclusion: For extended duration prophylaxis against VTE in hospitalized medically ill patients, the full 80 mg dose of extended duration betrixaban achieves higher serum concentrations than the 40 mg dose and is associated with improved efficacy across all cohorts relative to standard dose enoxaparin, without an excess risk of major bleeding. Based upon the approximate halving of plasma concentrations in this analysis and the lack of improvement in clinical outcomes, the reduced 40 mg dose may have been excessively downwardly adjusted. Conversely, the 80 mg dose was efficacious in all cohorts, including cohort 1. The inclusion of the 40 mg dose in the primary analysis may explain at least in part the marginal statistical result in the original report. Disclosures Cohen: Takeda: Consultancy; Medscape: Speakers Bureau; XO1: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria, Speakers Bureau; Daiichi Sankyo: Consultancy, Honoraria, Speakers Bureau; Portola: Consultancy, Honoraria, Speakers Bureau; Bristol-Myers Squibb: Consultancy, Honoraria, Speakers Bureau; NHS: Membership on an entity's Board of Directors or advisory committees; Lifeblood: Membership on an entity's Board of Directors or advisory committees; Department of Health: Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline: Consultancy, Speakers Bureau; Bayer: Consultancy, Honoraria, Speakers Bureau; Sanofi: Consultancy, Honoraria; Janssen: Consultancy; Aspen: Consultancy, Speakers Bureau; Boehringer Ingelheim: Consultancy, Speakers Bureau; Colation to Prevent Venous Thromboembolism: Other: Founder; Leo Pharma: Consultancy; UK Government Health Select Committee: Membership on an entity's Board of Directors or advisory committees; Johnson & Johnson: Consultancy, Honoraria, Speakers Bureau; ONO: Consultancy, Honoraria. Goldhaber:Portola: Consultancy. Hull:Portola: Consultancy. Hernandez:Portola: Consultancy. Gold:Portola Pharmaceuticals: Employment. Wiens:Portola: Employment, Equity Ownership. Harrington:Portola: Consultancy. Gibson:Portola: Consultancy.
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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 | 0.003 | 0.003 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.002 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.003 | 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".