Association between ticagrelor plasma concentration and bleeding events in Chinese patients with acute coronary syndrome

The effect of gene polymorphism on ticagrelor metabolism: an in vitro study of 22 CYP3A4 variants in Chinese Han population

Background

Ticagrelor is a novel oral antiplatelet agent which can selectively inhibit P2Y12 receptor. Bleeding and dyspnea are common adverse reactions of ticagrelor in clinic. The side effects of ticagrelor are correlated with the plasma concentration of ticagrelor.

Objective

This study aimed to evaluate the catalytic characteristics of 22 CYP3A4 alleles identified in the Chinese Han population on the metabolism of ticagrelor in vitro, focusing on the effect of CYP3A4 polymorphism on ticagrelor metabolism.

Methods

In this study, insect cells were used to express 22 CYP3A4 variants, which were then incubated with 1-50 µM ticagrelor at 37 °C for 30 minutes to obtain the metabolite (AR-C124910XX). AR-C124910XX was detected by UHPLC-MS/MS to calculate the kinetic parameters, including Km, Vmax and CLint.

Results

Compared to the wild-type, most CYP3A4 alleles exhibited significant differences in intrinsic clearance. The intrinsic clearance of CYP3A4*11, *18 and *33 was much higher than that of wild-type; four variants exhibited similar intrinsic clearance values as the wild-type enzyme; The remaining 14 variants showed significantly reduced intrinsic clearance values, ranging from 1.48% to 75.11% of the wild-type; CYP3A4*30 displayed weak or no activity.

Conclusion

This study conducted a comprehensive assessment of the effect of CYP3A4 variants on ticagrelor's metabolism. The results suggested that there is allele-specific activity towards ticagrelor in vitro. These findings can provide some insights and predictions for treatment strategies and risk assessments associated with ticagrelor in clinical practice.

Population Pharmacokinetic/Pharmacodynamic Models for P2Y12 Inhibitors: A Systematic Review and Clinical Appraisal Using Exposure Simulation

BACKGROUND AND OBJECTIVE

Recent research indicates a correlation between plasma concentration of P2Y12 inhibitors and clinical events, particularly bleeding, which significantly impeded their clinical therapeutic performance. It is therefore vital to delve into the factors that might affect the plasma concentration. The study aims to summarize population pharmacokinetics/pharmacodynamics (PopPKPD) models for commonly prescribed P2Y12 inhibitors (clopidogrel, prasugrel, and ticagrelor) and assess bleeding risk in specific individual groups.

METHODS

The PopPKPD models of P2Y12 inhibitors were collected and summarized based on predetermined inclusion and exclusion criteria. The collected models were replicated in simulations, which were used to assess factors affecting plasma concentrations of P2Y12 inhibitors. Simulation results for special populations were compared to therapeutic window based on reported exposure-effect relationships (PK/PD-related bleeding and thrombotic clinical outcomes) to predict bleeding risk in special populations with different dosing regimens and cumulative covariates.

RESULT

Finally, 12 studies were included for PK simulation, 7 of which that also included PD data were subjected to further analysis, with the majority being based on Phase I or II trials. Simulations showed that several covariates such as female gender, weight, elderly can significantly impact on exposure, with special populations reaching up to 179% of the general population. However, after dose adjustment, blood concentrations for special populations can reach approximately ±20% of general population exposure. Therefore, lowering the maintenance dose of ticagrelor from 90 to 60 mg bid was first recommended to reduce bleeding risk without significantly increasing ischemic risk, particularly in elderly, small-weight Asian females.

CONCLUSION

Lowering the maintenance dose of ticagrelor from 90 to 60 mg bid effectively reduces bleeding risk without increasing thrombotic infarction risk in elderly, small-weight Asian females.

Effectiveness of dual antiplatelet de-escalation therapy on the prognosis of patients with ST segment elevation myocardial infarction undergoing percutaneous coronary intervention

AIM

To investigate the effectiveness of de-escalation of ticagrelor (from ticagrelor 90 mg to clopidogrel 75 mg or ticagrelor 60 mg) on the prognosis of patients with ST segment elevation myocardial infarction (STEMI) undergoing percutaneous coronary intervention (PCI) after 3 months of oral dual antiplatelet therapy (DAPT).

METHODS

From March 2017 to August 2021, 1056 patients with STEMI in a single centre, through retrospective investigation and analysis, were divided into intensive (ticagrelor 90 mg), standard (clopidogrel 75 mg after PCI) and de-escalation groups (clopidogrel 75 mg or ticagrelor 60 mg after 3 months of treatment with 90 mg ticagrelor) based on the type and dose of P2Y₁₂ inhibitor 3 months after PCI, and the patients had a ≥ 12-month history of oral DAPT. The primary end point was major adverse cardiovascular and cerebrovascular events (MACCEs) during the 12-month follow-up period, including composite end points of cardiac death, myocardial infarction, ischaemia-driven revascularization and stroke. The major safety endpoint was bleeding events.

RESULTS

The results showed that during the follow-up period, there was no statistically significant difference in the incidence of MACCEs between the intensive and de-escalation groups (P > 0.05). The incidence of MACCEs in the standard treatment group was higher than that in the intensive treatment group (P = 0.014), but the incidence of bleeding events in the de-escalation group was significantly lower than that in the standard group (9.3% vs. 18.4%, χ²=7.191, P = 0.027). The Cox regression analysis showed that increases in haemoglobin (HGB) (HR = 0.986) and estimated glomerular filtration rate (eGFR) (HR = 0.983) could reduce the incidence of MACCEs, while old myocardial infarction (OMI) (P = 0.023) and hypertension (P = 0.013) were independent predictors of MACCEs.

CONCLUSION

For STEMI patients undergoing PCI, the de-escalation scheme of ticagrelor to clopidogrel 75 mg or ticagrelor 60 mg at 3 months after PCI was related to the reduction of bleeding events, especially minor bleeding events, without an increase in ischaemic events.