Bleeding events and maintenance dose of prasugrel: BLESS pilot study

OBJECTIVE To evaluate changes in residual platelet reactivity (RPR) over time, and bleeding and ischaemic events rate using 5 vs 10 mg maintenance dose (MD) regimens of prasugrel 1 month after acute coronary syndrome (ACS). BACKGROUND The optimal level of RPR with prasugrel may change over time after an ACS. METHODS After 60 mg loading dose of prasugrel (T0) followed by 10 mg/day for 1 month, patients were randomised to receive prasugrel 10 mg/day (n=95, group A) or 5 mg/day MD (n=98, group B) up to 1 year. RPR was assessed at T0, 37 (T1) and 180 days (T2). The primary end point was Bleeding Academic Research Consortium (BARC) bleeding events ≥2 between 1 and 12 months, and the secondary composite end point was cardiac death, myocardial infarction, stroke and definite/probable stent thrombosis. RESULTS From T0 to T1, RPR significantly increased in both groups A and B and the increase was higher for group B (δ ADP 10 µmol: 13.8%±14.7% vs 23.5%±19.2%, p=0.001). At T2 a lower rate of high RPR patients were found in group A (2.6% vs13.3%; p=0.014). The BARC type ≥2 bleeding occurred in 12.6% of group A versus 4.1% of group B (OR 0.29, 95% CI 0.09 to 0.94) and secondary end point in 2.1% vs 1.0% (p=0.542), respectively, without stent thrombosis. CONCLUSIONS RPR increases shifting from 60 mg loading dose to 10 mg/day prasugrel MD with a further increase of RPR reducing prasugrel MD to 5 mg 1 month after ACS. Clinical value of these pharmacodynamic findings should be proved in larger clinical trials. TRIAL REGISTRATION NUMBER NCT01790854.