EINSTEIN Jr
(2019)Objective
Rivaroxaban versus standard anticoagulation in children with acute venous thromboembolism.
Study Summary
Intervention
Bodyweight-adjusted rivaroxaban (20 mg equivalent adult dose) given once or twice daily vs. standard anticoagulation (initial LMWH or UFH, then continued with LMWH, UFH, or VKA) for 3 months (or 1 month for catheter-related VTE).
Inclusion Criteria
Children aged <18 years with acute symptomatic or asymptomatic VTE confirmed by imaging. Excluded high bleeding risk, severe renal or hepatic dysfunction, or short life expectancy.
Study Design
Arms: Rivaroxaban vs. Standard Anticoagulation
Patients per Arm: Rivaroxaban: 335, Standard Therapy: 165
Outcome
Bottom Line
In 500 children (0-17yr) with acute VTE, bodyweight-adjusted rivaroxaban resulted in similar recurrent VTE (1% vs 3%; HR 0.40; 0.11-1.41) vs standard anticoagulation, with no increase in major bleeding (0% vs 1%). Rivaroxaban produced significantly greater clot resolution (complete 38% vs 26%; OR 1.70; P=0.012). First completed phase 3 DOAC trial in children. Oral suspension developed for young children.
Major Points
- Recurrent VTE: 1% (4/335) rivaroxaban vs 3% (5/165) standard (HR 0.40; 0.11-1.41).
- No major bleeding in rivaroxaban arm (0%) vs 2 in comparator (1%). CRNM bleeding 3% vs 1%.
- Significantly greater clot resolution: complete 38% vs 26% (OR 1.70; 95% CI 1.11-2.58; P=0.012).
- Net clinical benefit (recurrent VTE + major bleed): 1% vs 4% (HR 0.30; 0.08-0.93).
- First completed phase 3 DOAC trial in children — largest pediatric anticoagulation trial (500 children, 107 hospitals, 28 countries).
- Novel oral suspension (1 mg/mL) for children <6yr eliminates parenteral anticoagulation/lab monitoring.
- Bodyweight-adjusted dosing targeting adult 20mg-equivalent exposure: once/twice/thrice daily based on weight.
- 97% first-episode VTE; 51% non-catheter-related, 27% catheter-related, 22% cerebral vein/sinus thrombosis.
- Not formally powered for non-inferiority (upper CI 1.41 exceeds standard margins).
- Bayer/Janssen funded. Led to regulatory approval of rivaroxaban for pediatric VTE.
Study Design
- Study Type
- Randomized, open-label, multicenter, active-controlled, phase 3 trial
- Randomization
- Yes
- Blinding
- Open-label with blinded outcome adjudication
- Sample Size
- 335
- Follow-up
- 3 months (6 months in children <2y with catheter-related VTE)
- Centers
- 107
- Countries
- Europe, North America, South America, Asia
Primary Outcome
Definition: Symptomatic recurrent VTE
| Control | Intervention | HR/OR | P-value |
|---|---|---|---|
| 3/121 (2.5%) | 4/335 (1.2%) | 0.33 (0.03–3.16) | NS |
Limitations & Criticisms
- Open-label design could introduce bias despite blinded adjudication
- Relatively short treatment/follow-up duration
- Event rates were low, limiting statistical power for rare outcomes
- No power to assess superiority
Citation
Lancet Haematol. 2019 Jan;6(1):e89–e98