T3CAD
(2026)Objective
To evaluate the efficacy and safety of a tocotrienol-rich vitamin E complex (HOV12020) for preventing clinical progression in patients with CADASIL, the most common monogenic small vessel disease with no available disease-modifying therapy.
Study Summary
• Bayesian analysis showed low posterior probability of benefit, meeting predefined futility criteria
• No significant differences in secondary endpoints or exploratory MRI measurements
• HOV12020 was well tolerated with excellent safety profile and no excess of adverse events
Intervention
Tocotrienol-rich vitamin E complex (HOV12020) — one capsule (285 mg total tocotrienols and tocopherols) twice daily (total 570 mg/day) for 24 months, vs vitamin-E–stripped soybean oil placebo.
Inclusion Criteria
Age 45-75 years; genetically or biopsy-confirmed CADASIL; ≥1 prevalent lacune on MRI; confluent white matter hyperintensities (Fazekas grade 2 or 3); MMSE ≥15; modified Rankin Scale 0-3.
Study Design
Arms: HOV12020 tocotrienol-rich vitamin E complex 570 mg/day (n=25) vs Placebo (n=26)
Patients per Arm: HOV12020: 25; Placebo: 26
Outcome
• No significant differences in secondary clinical endpoints
• No significant differences in exploratory MRI markers of disease progression
• Excellent safety profile with no excess adverse events vs placebo
Bottom Line
In patients with symptomatic CADASIL, 24 months of tocotrienol-rich vitamin E (HOV12020) did not reduce stroke, disability, or cognitive decline; Bayesian analysis confirmed futility. The compound is unlikely to confer benefit in advanced CADASIL, though it was very well tolerated.
Major Points
- First randomised, placebo-controlled preventive intervention trial in CADASIL
- Treatment failure (composite of stroke, disability progression, or cognitive decline) occurred in 68.0% on HOV12020 vs 61.5% on placebo over 24 months
- Bayesian analysis met predefined futility criteria — low posterior probability of treatment benefit
- Placebo event rate (61.5%) far exceeded the 40% initially expected, indicating rapid progression in symptomatic CADASIL
- No significant differences in secondary clinical endpoints or exploratory MRI markers
- Excellent safety and tolerability — no excess adverse events vs placebo
- Demonstrates feasibility of Bayesian small-sample designs in rare, slowly progressive cerebrovascular diseases
- Findings suggest future trials should target earlier disease stages in CADASIL
Study Design
- Study Type
- Single-centre, randomised, double-blind, placebo-controlled, pilot/phase 2 trial with Bayesian analysis framework
- Randomization
- Yes
- Blinding
- Double-blind — participants, investigators, outcome assessors, and data analysts blinded; placebo identical in appearance and administration schedule to active treatment
- Sample Size
- 51
- Follow-up
- 24 months
- Centers
- 1
- Countries
- France
Primary Outcome
Definition: Treatment failure within 24 months, defined as occurrence of at least one of: (1) centrally adjudicated stroke event; (2) increase in modified Rankin Scale ≥1 point to a score ≥2 attributable to CADASIL; or (3) cognitive decline defined as ≥4-point increase in VADAS-Cog score
| Control | Intervention | HR/OR | P-value |
|---|---|---|---|
| 61.5% (placebo) | 68.0% (HOV12020) | - |
Limitations & Criticisms
- Small single-centre sample (n=51) limits power for definitive efficacy conclusions outside the Bayesian futility framework
- Placebo event rate (61.5%) far exceeded the 40% expected, suggesting enrollment of more advanced disease than anticipated — limits ability to detect benefit
- Authors acknowledge findings apply to advanced-stage CADASIL; earlier disease stages may still respond
- Single-centre French cohort may limit generalisability
- 24-month duration may be insufficient for a slowly progressive disease
Citation
eClinicalMedicine 2026;94:103853. Published Online 30 March 2026.