The design and rationale for the Acute Medically Ill Venous Thromboembolism Prevention with Extended Duration Betrixaban (APEX) study
Bibliographic record
Abstract
Randomized clinical trials have identified a population of acute medically ill patients who remain at risk for venous thromboembolism (VTE) beyond the standard duration of therapy and hospital discharge. The aim of the APEX study is to determine whether extended administration of oral betrixaban (35-42 days) is superior to a standard short course of prophylaxis with subcutaneous enoxaparin (10 ± 4 days followed by placebo) in patients with known risk factors for post-discharge VTE. Patients initially are randomized to receive either betrixaban or enoxaparin (and matching placebo) in a double dummy design. Following a standard duration period of enoxaparin treatment (with placebo tablets) or betrixaban (with placebo injections), patients receive only betrixaban (or alternative matching placebo). Patients are considered for enrollment if they are older than 40 years, have a specified medical illness, and restricted mobility. They must also meet the APEX criteria for increased VTE risk (aged ≥75 years, baseline D-Dimer ≥2× upper the limit of "normal", or 2 additional ancillary risk factors for VTE). The primary efficacy end point is the composite of asymptomatic proximal deep venous thrombosis, symptomatic deep venous thrombosis, non-fatal (pulmonary embolus) pulmonary embolism, or VTE-related death through day 35. The primary safety outcome is the occurrence of major bleeding. We hypothesize that extended duration betrixaban VTE prophylaxis will be safe and more effective than standard short duration enoxaparin in preventing VTE in acute medically ill patients with known risk factors for post hospital discharge VTE.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 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) | 0.000 | 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 teacher head, 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".