OBJECTIVE: Dual antiplatelet therapy (DAPT) with aspirin and a P2Y12 receptor inhibitor is the cornerstone of treatment in patients with acute coronary syndromes (ACS) and in those undergoing percutaneous coronary intervention (PCI). In current clinical situation, availability of different oral P2Y12 inhibitors (clopidogrel, prasugrel, and ticagrelor) has enabled physicians to switch among therapies owing to specific clinical scenarios. Although optimum time, loading dose and interval of transition between P2Y12 inhibitors is still controversial and needs further evidence, switching between oral inhibitors frequently occurs in clinical practice for several reasons. DATA SOURCES: This review was based on data in articles published in PubMed up to June 2018, with the following keywords "antiplatelet therapy", "ACS", "PCI", "ticagrelor", and "clopidogrel". STUDY SELECTION: Original articles and critical reviews on de-escalation strategy in ACS patients after PCI were selected. References of the retrieved articles were also screened to search for potentially relevant papers. RESULTS: Safety concerns associated with switching between antiplatelet agents, has prompted the use of clopidogrel for patients with ACS especially after PCI as a de-escalation strategy. Practical considerations for de-escalating therapies in patients with ACS such as reducing dose of P2Y12 inhibitors or shortening duration of DAPT (followed by aspirin or P2Y12 receptor inhibitor monotherapy) as potential options are yet to be standardized and validated. CONCLUSIONS Current review will provide an overview of the pharmacology of common P2Y12 inhibitors, definitions of de-escalation and different de-escalating strategies and its outcomes, along with possible direction to be explored in de-escalation.
Acute Coronary Syndrome ; drug therapy ; therapy ; Aspirin ; therapeutic use ; Diamines ; therapeutic use ; Humans ; Percutaneous Coronary Intervention ; Platelet Aggregation Inhibitors ; therapeutic use ; Purinergic P2Y Receptor Antagonists ; therapeutic use ; Thiazoles ; therapeutic use

Acute Coronary Syndrome/drug therapy* ; Aged ; Clopidogrel/therapeutic use* ; Humans ; Percutaneous Coronary Intervention ; Platelet Aggregation Inhibitors/therapeutic use* ; Purinergic P2Y Receptor Antagonists/therapeutic use* ; Ticagrelor/therapeutic use* ; Treatment Outcome

INTRODUCTIONTicagrelor is a novel antiplatelet drug developed to reduce atherothrombosis. The PLATO trial compared ticagrelor and aspirin to clopidogrel and aspirin in patients with acute coronary syndromes (ACS). Ticagrelor was found to be superior in the primary composite endpoint of cardiovascular death, myocardial infarction or stroke, without increasing major bleeding events. The current study estimates the lifetime cost-effectiveness of ticagrelor relative to generic clopidogrel from a Singapore public healthcare perspective.

METHODSThis study used a two-part cost-effectiveness model. The first part was a 12-month decision tree (using PLATO trial data) to estimate the rates of major cardiovascular events, healthcare costs and health-related quality of life. The second part was a Markov model estimating lifetime quality-adjusted survival and costs conditional on events during the initial 12 months. Daily drug costs applied were SGD 1.05 (generic clopidogrel) and SGD 6.00 (ticagrelor). Cost per quality-adjusted life years (QALY) was estimated from a Singapore public healthcare perspective using life tables and short-term costs from Singapore, and long-term costs from South Korea. Deterministic and probabilistic sensitivity analyses were performed.

RESULTSTicagrelor was associated with a lifetime QALY gain of 0.13, primarily driven by lower mortality. The resulting incremental cost per QALY gained was SGD 10,136.00. Probabilistic sensitivity analysis indicated that ticagrelor had a > 99% probability of being cost-effective, given the lower recommended WHO willingness-to-pay threshold of one GDP/capita per QALY.

CONCLUSIONBased on PLATO trial data, one-year treatment with ticagrelor versus generic clopidogrel in patients with ACS, relative to WHO reference standards, is cost-effective from a Singapore public healthcare perspective.

Acute Coronary Syndrome ; drug therapy ; economics ; Adenosine ; analogs & derivatives ; economics ; therapeutic use ; Aspirin ; administration & dosage ; Clinical Trials as Topic ; Cost-Benefit Analysis ; Decision Trees ; Drug Costs ; Humans ; Markov Chains ; Platelet Aggregation Inhibitors ; administration & dosage ; economics ; Purinergic P2Y Receptor Antagonists ; administration & dosage ; economics ; Quality-Adjusted Life Years ; Republic of Korea ; Singapore ; Ticlopidine ; administration & dosage ; analogs & derivatives