Trial of Rivaroxaban vs. Aspirin in Stroke Prevention Terminated
Background on Ischemic Strokes
Ischemic strokes occur when blood vessels in the brain become blocked by blood clots. Approximately 20% of these strokes are classified as embolic, which means the clot originates from another part of the body before traveling to the brain. Due to the high risk of recurrence associated with ischemic strokes, aspirin is commonly prescribed to mitigate this risk.
Purpose of the Trial
A large-scale trial, funded by Bayer and Janssen, aimed to compare the effectiveness of rivaroxaban—a blood thinner used in patients with atrial fibrillation—with aspirin for preventing recurrent embolic strokes. Key findings from the study were reported in the BMJ and originally published in the New England Journal of Medicine.
Trial Design and Early Termination
The trial enrolled a total of 7,213 patients and was designed to last for two years. Participants who had recently experienced an ischemic stroke were assigned to receive either rivaroxaban or aspirin during the treatment period. However, after 11 months, the trial was halted prematurely due to unfavorable risk-benefit outcomes.
Results of the Study
The study found no significant difference in stroke prevention between the two treatments. Specifically, strokes recurred in 5.1% of patients taking rivaroxaban, compared to 4.8% in the aspirin group. More concerning, patients taking rivaroxaban experienced a markedly higher risk of major bleeding, with rates of 1.8% versus 0.7% for those on aspirin.
Future Research
Although this trial was terminated, ongoing studies are exploring other anticoagulants in comparison to aspirin for stroke prevention.
References
(1) Wise J. Anticoagulant trial to prevent recurrent stroke stops early because of risk of bleeding. BMJ. 2018. doi:10.1136/bmj.k2160.
(2) Hart R, Sharma M, Mundl H, et al. Rivaroxaban for stroke prevention after embolic stroke of undetermined source. New England Journal of Medicine. 2018. doi:10.1056/NEJMoa1802686.