Background and Purpose—The results of the Sarpogrelate-Aspirin Comparative Clinical Study for Efficacy and Safety in Secondary Prevention of Cerebral Infarction (S-ACCESS), a randomized double-blind study of sarpogrelate (selective 5-HT_2A receptor antagonist) versus aspirin in 1510 Japanese patients, have been reported. But S-ACCESS failed to demonstrate noninferiority of sarpogrelate to aspirin for preventing the recurrence of cerebral infarction. Here we compare the characteristics of sarpogrelate and aspirin in various subgroups.

Methods—Subgroups were predefined from patients' baseline characteristics. Hazard ratio (HR) and 95% confidence interval (CI) for sarpogrelate versus aspirin were calculated for primary (cerebral infarction) and secondary (serious vascular events) end points. Interactions between treatment effects and subgroup variables were examined by post hoc analysis.

Results—No significant difference in outcome between sarpogrelate and aspirin was found across multiple predefined subgroups. In post hoc analysis, a qualitative treatment interaction with diabetes mellitus was detected (P=0.166 for recurrence of cerebral infarction; P=0.098 for serious vascular events). HR for the recurrence of cerebral infarction with sarpogrelate versus that with aspirin was 0.87 (95% CI: 0.48 to 1.60) in diabetic patients and 1.51 (95% CI: 0.98 to 2.31) in nondiabetic patients. For serious vascular events, the corresponding HRs were 0.73 (95% CI: 0.42 to 1.25) and 1.28 (95% CI: 0.89 to 1.83).

Conclusions—No specific baseline characteristic resulting in a significant difference between the effects of sarpogrelate and aspirin was identified. Aspirin was superior in most subgroups, except diabetics. Sarpogrelate may be a useful treatment option for Japanese patients with diabetes.