The impact of generic clopidogrel bisulfate on platelet inhibition in patients with coronary artery stents: Results of the ACCEL-GENERIC study

Abstract

Background/Aims: In patients with coronary artery stents, the cost of clopidogrel has been cited as a factor in the premature discontinuation of therapy. Thus, the introduction of lower-cost generic clopidogrel may increase patient compliance. However, platelet inhibition by generic clopidogrel has not been compared to the original clopidogrel formulation in patients with coronary artery stents. & Methods: We prospectively enrolled 20 patients receiving chronic therapy with the original clopidogrel bisulfate (Plavix®). After assessing patient compliance with Plavix®, maintenance therapy was switched to generic clopidogrel bisulfate Plavitor®).Platelet reactivity was assessed at baseline and 30-day after the switch using conventional aggregometry and the VerifyNow P2Y12 assay. & Results: All patients completed maintenance therapy with Plavitor®. Before and after switching therapy maximal (36.5 ± 7.9% vs. 39.8 ± 16.2%, p = 0.280) and late platelet aggregation (23.5 ± 10.9% vs. 29.1 ± 18.3%, p = 0.156) with 5 μmol/L adenosine diphosphate (ADP) stimulus did not differ. Likewise, 20 μmol/L ADP-induced platelet aggregation and P2Y12 reaction unit in patients on Plavitor® therapy was comparable to that in patients on Plavix® therapy. However, Bland-Altman analysis showed wide limits of agreement between measured platelet reactivity on Plavix® vs. Plavitor® therapies. & Conclusions: Among patients on Plavix® maintenance therapy with coronary stents, replacement with Plavitor® shows a comparable inhibition of ADP-induced platelet aggregation. However, due to poor inter-therapy agreement, between two regimens, physicians may be cautious when introducing generic clopidogrel bisulfate.