Protocol for Cilostazol Stroke Prevention Study for Antiplatelet Combination (CSPS.com): a randomized, open-label, parallel-group trial

RATIONALE AND AIMS Monotherapy with antiplatelet agents is only modestly effective in secondary prevention of ischemic stroke (IS), particularly in patients with multiple risk factors such as cervicocephalic arterial stenosis, diabetes, and hypertension. While dual antiplatelet therapy (DAPT) with aspirin and clopidogrel reduced IS recurrence, particularly in the early stages after IS, it increased the risk of bleeding. Compared with aspirin, cilostazol prevented IS recurrence without increasing the incidence of serious bleeds. In patients with intracranial arterial stenosis, no significant increase in bleeding events was observed for DAPT with cilostazol and aspirin, compared to that for aspirin monotherapy. DAPT involving cilostazol may therefore be safer than conventional DAPT. These findings prompted us to conduct the Cilostazol Stroke Prevention Study for Antiplatelet Combination (CSPS.com; ClinicalTrials.gov identifier: NCT01995370) to evaluate the safety and efficacy of DAPT involving cilostazol for secondary IS prevention, in comparison with that of antiplatelet monotherapy. DESIGN The CSPS.com is a multicenter, randomized, open-label, parallel-group trial. A total of 4000 high-risk patients with noncardioembolic IS will be randomized 8-180 days after onset to receive aspirin or clopidogrel monotherapy, or DAPT with cilostazol and aspirin or clopidogrel for at least one-year. STUDY OUTCOMES The primary outcome is IS recurrence. Secondary outcomes are composite occurrences of any stroke, death from any cause, myocardial infarction, vascular death, and other vascular events. DISCUSSION The CSPS.com is expected to provide evidence indicating whether secondary IS prevention in high-risk patients can be improved by using DAPT involving cilostazol.