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Apixaban Shows Similar Safety and Efficacy to Standard Care for Paediatric VTE
In a randomised trial of 229 children with venous thromboembolism, recurrent VTE or VTE-related mortality occurred in 2.6% of patients receiving apixaban and 2.7% receiving standard-of-care anticoagulation, with clinically relevant bleeding rates of 1.3% and 1.4% respectively. The overall safety and efficacy profiles were numerically comparable across both groups, though the descriptive design of the study precludes formal inferential conclusions.
What Was Studied
This trial investigated whether a fixed-dose-by-bodyweight-tier oral apixaban regimen is safe and effective for treating venous thromboembolism in patients younger than 18 years, including neonates. The primary efficacy outcome was a composite of recurrent VTE and VTE-related mortality during a 12-week main treatment phase, and the primary safety outcome was a composite of major and clinically relevant non-major bleeding events over the same period.
How It Was Studied
This was a prospective, open-label, multicentre, randomised, controlled descriptive trial conducted across 120 sites in 14 countries. A total of 229 paediatric patients with investigator-confirmed VTE were randomly assigned 2:1 to receive oral apixaban (n=155) or standard-of-care anticoagulation (n=74), which could comprise unfractionated heparin, low-molecular-weight heparin, or vitamin K antagonists per local practice. Randomisation was stratified by age, with the study population spanning from neonates (27 days or younger) through adolescents up to 18 years. Apixaban dosing was weight-tiered and age-specific, ranging from 0.1 mg twice daily in neonates to 10 mg twice daily (induction) and 5 mg twice daily (maintenance) in patients weighing 35 kg or more. The main treatment phase lasted 12 weeks, with an optional 6–12-week extension available for eligible apixaban-treated patients who required continued anticoagulation.
What Was Observed
- Recurrent VTE rates were nearly identical across arms. The composite primary efficacy endpoint was reached by 4 of 155 apixaban patients (2.6%, 95% CI 0.8–6.7) and 2 of 74 standard-of-care patients (2.7%, 95% CI 0.2–9.9). All events in both groups were recurrent VTE; no VTE-related deaths occurred. The wide confidence intervals in both arms reflect the limited sample size and preclude any definitive comparison.
- Clinically relevant bleeding was rare and no major bleeding was recorded in either group. The primary safety composite endpoint occurred in 2 of 152 apixaban-treated patients (1.3%, 95% CI 0.1–5.0) and 1 of 73 standard-of-care patients (1.4%, 95% CI 0.0–8.1). All bleeding events were classified as clinically relevant non-major, with zero major bleeding events in either arm during the main phase.
- General adverse event burden was similar between groups. Any-grade adverse events were reported in 86% of apixaban-treated patients versus 84% of standard-of-care patients. The most frequently reported events were headache (16% vs 15%), epistaxis (16% vs 19%), and vomiting (13% vs 5%). Three treatment-related serious adverse events occurred in the apixaban group — two cases of haematochezia and one of cerebral venous sinus thrombosis — and none in the standard-of-care group.
- No treatment-related deaths were recorded in either arm across the full study duration, which spanned a median of 83 days in both groups.
Why This Matters
The abstract notes an increasing incidence of VTE in children alongside a recognised absence of evidence-based treatment guidelines for direct oral anticoagulants in this population. This trial is designed to address that gap directly by evaluating a structured, weight-tiered dosing regimen across all paediatric age groups, including neonates, who represent a particularly underserved and pharmacologically complex subgroup. The findings provide prospective randomised data that may support the development of paediatric anticoagulation guidelines and broaden available treatment options for clinicians managing VTE in children.
How to Read This Result
Because this was a descriptive trial not formally powered for hypothesis testing, and because confidence intervals in both arms are wide — particularly in smaller age subgroups such as neonates (n=16) — the numerically similar rates between apixaban and standard care should be interpreted as hypothesis-generating rather than as confirmation of equivalence or non-inferiority.
Limitations
The study was descriptive by design and was not statistically powered to test superiority or non-inferiority, which substantially limits the strength of any inferential conclusions. The 2:1 randomisation ratio and overall sample size of 229 patients produce wide confidence intervals, reducing the precision of both efficacy and safety estimates. The open-label design introduces the possibility of performance or assessment bias, since neither patients nor clinicians were masked to treatment. Finally, the optional extension phase was available only to apixaban-treated patients, creating a structural asymmetry between the two arms that may complicate longer-term interpretation.