NIH Halts Arm of Clinical Trial Evaluating a Potential Stroke Treatment

Why It Matters

Stopping the rivaroxaban arm underscores the importance of rigorous safety oversight in stroke‑prevention research and may reshape anticoagulant strategies for intracranial atherosclerosis.

Key Takeaways

• NIH stops low-dose rivaroxaban arm for safety concerns
• DSMB cites increased adverse events and futility
• CAPTIVA still evaluates ticagrelor and clopidogrel combos
• Trial enrolls up to 1,683 stroke patients nationwide
• Results will guide future antithrombotic strategies

Pulse Analysis

Stroke remains a leading cause of disability, and clinicians constantly seek therapies that balance clot prevention with bleeding risk. The CAPTIVA study was designed to address this dilemma by testing two novel antithrombotic combinations against the standard clopidogrel‑aspirin regimen in patients with severe intracranial artery narrowing. By enrolling over a thousand participants across more than a hundred sites, the trial promised robust data on efficacy, safety, and real‑world applicability, positioning it as a potential benchmark for future stroke‑prevention protocols.

The Data Safety and Monitoring Board’s decision to discontinue the low‑dose rivaroxaban arm reflects the trial’s built‑in safeguards. Early signals of increased safety events—likely hemorrhagic complications—combined with futility analyses indicated that the 2.5 mg twice‑daily dose would not deliver a meaningful reduction in recurrent stroke. This outcome highlights the challenges of repurposing anticoagulants for intracranial atherosclerosis, where the therapeutic window is narrow and patient heterogeneity can amplify risks.

Beyond the immediate implications for rivaroxaban, the halt sends a broader message to pharmaceutical developers and academic investigators: rigorous, independent monitoring is essential for advancing stroke therapeutics. The remaining arms of CAPTIVA will still generate valuable comparative data on ticagrelor‑aspirin versus clopidogrel‑aspirin, informing guideline updates and future combination‑therapy trials. NIH’s transparent response reinforces confidence in federally funded research and underscores the agency’s role in protecting participants while steering the field toward safer, more effective interventions.

NIH halts arm of clinical trial evaluating a potential stroke treatment

Tuesday, February 10, 2026

The National Institutes of Health (NIH) has stopped an investigational treatment arm of the Comparison of Anti‑coagulation and Anti‑platelet Therapies for Intracranial Vascular Atherostenosis (CAPTIVA study), following a regular review by the Data Safety and Monitoring Board (DSMB). The DSMB is an independent group of experts that regularly check if the study is safe. NIH’s National Institute of Neurological Disorders and Stroke, the trial’s funder, accepted the DSMB recommendation that CAPTIVA discontinue the low‑dose rivaroxaban arm of the trial due to an increase in safety events and evidence of futility, a pre‑specified stopping point to enable the study to end if early results showed the treatment is unlikely to help people. Rivaroxaban is a U.S. Food and Drug Administration‑approved anticoagulant medication used to treat or prevent blood clots. All study sites that have active participants randomized to the discontinued arm have received instructions for drug discontinuation. Study participants who have completed their evaluation of the discontinued arm will be contacted by the site where they received treatment. Participant safety remains NIH’s top priority.

The CAPTIVA study is a large, two‑stage, double‑blind randomized trial in participants age 30 and older with a stroke attributed to 70‑99 % narrowing, or stenosis, of a major intracranial artery. The study is testing whether either of two new treatments works better than the current treatment to prevent another stroke. The study, part of NIH’s StrokeNet, is in the midst of enrolling and evaluating up to 1,683 volunteers at over 100 study sites over a four‑year period. Participants were randomized 1:1:1 to one year of treatment with:

1. Ticagrelor (180 mg loading dose, then 90 mg twice daily) plus aspirin (81 mg daily)

2. Low‑dose rivaroxaban (2.5 mg twice daily) plus aspirin (81 mg daily)

3. Clopidogrel (600 mg loading dose, then 75 mg daily) plus aspirin (81 mg daily)

In addition, participants will receive intensive risk‑factor management and lifestyle coaching. They will be evaluated at one month, four months, eight months, and one year after randomization into one of the study arms. At these intervals, participants will have their blood pressure checked, risk factors optimized and will be assessed for study outcomes.

CAPTIVA will not determine which new treatment is best. It will only show if either new treatment is better than what doctors currently use. Comparing the two new treatments directly would require many more patients. Nevertheless, CAPTIVA will provide important safety and efficacy data on both novel therapies.

The CAPTIVA Study and NIH’s StrokeNet are funded by NIH’s NINDS.

About the National Institute of Neurological Disorders and Stroke (NINDS):

NINDS is the nation’s leading funder of research on the brain and nervous system. The mission of NINDS is to seek fundamental knowledge about the brain and nervous system and to use that knowledge to reduce the burden of neurological disease. https://www.ninds.nih.gov

About the National Institutes of Health (NIH):

NIH, the nation's medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit https://www.nih.gov.