Results of a recent study demonstrate that while both ticagrelor and prasugrel effectively treat high on-treatment platelet reactivity, ticagrelor produced significantly higher platelet inhibition in patients with acute coronary syndrome exhibiting high on-treatment platelet reactivity while taking clopidogrel 24 hours after percutaneous coronary intervention.
The prospective, single-center, single-blind study included 44 patients with ACS who had high on-treatment platelet reactivity (HTPR) while on clopidogrel 24 hours post-PCI. The patients were randomly assigned to one of two group: ticagrelor (Brilinta, AstraZeneca) 90 mg twice daily or prasugrel (Effient, Eli Lilly) 10 mg once daily. Treatment was administered for 15 days with a crossover directly to the alternate treatment for another 15 days.
At the end of the two treatment periods, platelet reactivity was lower with ticagrelor (32.9 PRU; 95% CI, 18.7-47.2) compared with prasugrel (101.3 PRU; 95% CI: 86.8-115.7). A significant least squares mean difference of –68.3 PRU (95% CI: –88.6 to –48.1) was recorded. Researchers also reported that the HTPR rate was 0% with ticagrelor and 2.4% with prasugrel at the end of two treatment periods.
Other data revealed that no patients in either treatment group experienced a major bleeding event.
“In this first direct pharmacodynamic comparison of ticagrelor with prasugrel in ACS patients exhibiting HTPR while on clopidogrel post-PCI, we have demonstrated that ticagrelor provides stronger than prasugrel platelet inhibition. However, both agents effectively treated the phenomenon of HTPR in our population,” the researchers wrote in the study discussion.
The researchers cautioned that “the clinical squelae of [this] study are only speculative.” They said further research may help determine whether the pharmacodynamic differences observed in this study translate into differences in clinical safety or efficacy.
Disclosure: The study was supported by the Research Committee of the Patras University Medical School. Dr. Alexopoulos reports receiving speaker fees from AstraZeneca, Boehringer-Ingelheim, Pharmaserve/Eli Lilly & Co., and Sanofi-Aventis. All other researchers report no relevant financial disclosures.