Phase 1 study of novel anti-platelet agent to overcome pharmacogenomic limitations of clopidogrel

AIMS: Clopidogrel is the most commonly prescribed thienopyridine as part of dual anti-platelet therapy for the treatment of cardiovascular diseases. However, clopidogrel responsiveness shows variability based on CYP2C19 polymorphism. Therefore, we planned a study with an objective of evaluating safety, tolerability, pharmacodynamics and pharmacokinetics of a novel thienopyridine antiplatelet agent AT-10 in healthy Indian subjects compared with standard dosage regimen of clopidogrel based on their CYP2C19 genotyping. METHODS: Two CYP2C19 genotype-based groups were identified, that is, poor metabolisers and extensive metabolisers, with 20 subjects in each group (n=40) for participating in a randomised, two-period, crossover study. Each study period lasted 6 days including administration of loading and maintenance doses of AT-10 (40 mg/10 mg) or clopidogrel (300 mg/75 mg). The pharmacokinetics and pharmacodynamics were assessed on day 1 and day 6 at several time intervals. RESULTS: Overall result of pharmacodynamic parameters showed that mean %inhibition of platelet aggregation between AT-10 and clopidogrel in all subjects at 6 hours postdose (loading dose) (AT-10: clopidogrel; 73.30% vs 18.53%) and 6 hours postdose on day 6 (maintenance dose) (AT-10: clopidogrel; 83.41% vs 51.19 %) obtained from the AT-10 group was significantly higher than the clopidogrel group. Further, %inhibition of platelet aggregation from AT-10 treatment in poor metaboliser group was significantly higher than the clopidogrel treatments in extensive metaboliser group.Overall pharmacokinetic comparison in all subjects indicates that AT-10 gives greater exposure to active Metabolite H4 than clopidogrel. CONCLUSION: AT-10 showed better inhibition of platelet aggregation in poor metabolizers as compared to Clopidogrel. AT-10 may emerge as a potential alternative to Clopidogrel as an anti-platelet drug. It can be further developed in clinical studies for the unmet medical needs in management of CVDs and overcome the pharmacogenomic limitations of Clopidogrel. TRIAL REGISTRATION NUMBER: Clinical Trial Registry-India URL: http://ctri.nic.in. REGISTRATION NUMBER: CTRI/2021/03/032206.