(55) Initial Choice and Switching of P2Y12 Inhibitors Among Patients with Acute Coronary Syndrome (ACS) After Percutaneous Coronary Intervention (PCI)

Publication Number: 386

Background: Dual antiplatelet therapy with aspirin and a P2Y12 inhibitor (ticagrelor (TIC), prasugrel (PRAS), or clopidogrel (CLOP)) is critical for patients with ACS and PCI to prevent major adverse cardiovascular events (MACE) through platelet inhibition. Compared with CLOP, the more potent P2Y12 inhibitors, TIC/PRAS, were superior in reducing MACE in clinical trials but have a higher bleeding risk, which is more pronounced as the treatment duration extends. Thus, treatment recommendations consider de-escalation from TIC/PRAS to CLOPto reduce the bleeding risk during the maintenance stage. There are no recent data on the initial choice and switching/de-escalation of P2Y12 inhibitors after PCI in real-world settings.

Objectives: To describe the initial choice of P2Y12 inhibitors and switching rate and direction after PCI discharge.

Methods: We conducted a retrospective cohort study using IBM® MarketScan® Commercial claims data from 2009 to 2018. We included patients ≥ 18 years, diagnosed with ACS, discharged after PCI, without prior use of P2Y12 inhibitor in the past 12 months. The first P2Y12 inhibitor prescription had to be filled within 30 days after PCI discharge (index date). Patients were required to have at least 12-month continuous medical and pharmacy enrollment before the index date to assess eligibility criteria. They were followed for 12 months. A switching event was defined as the first-time change of P2Y12 inhibitors from the original choice during the 12 months maintenance period, which included escalation (CLOP –> PRAC/TIC), de-escalation (PRAS/TIC –>CLOP), and switch (PRAS –> TIC or vice versa). Patients had to stay on treatment (gaps between two prescriptions < 30 days) to be assessed for switching.

Results: 42,199 patients initiating P2Y12 inhibitors after PCI discharge were included. Use of CLOP decreased across the study period with a prevalence from 97.5% in 2009 to 32.3% in 2018. The preference for more potent inhibitors increased with prevalence from 2.5% (PRAS 2.5%, TIC 0%) in 2009 to 67.7% (PRAS 10.1%, TIC 57.6%) in 2018.
A total of 4,245 switching events were identified. The switching rate increased from 1.4% in 2009 to 15.9% in 2018, with stable escalation proportions of 1.3% in 2009 to 1.2% in 2018 among CLOP initiators. The de-escalation proportion for those initiating PRAS/TIC increased from 0.1% in 2009 to 13.0% in 2018. Switches within PRAS/TIC were uncommon with about 1% across 2009 to 2018.

Conclusions: More potent P2Y12 inhibitors are increasingly preferred as initial therapy following PCI. Switching increased over the study years, mainly due to de-escalation. Further studies on predictors of switching and real-world outcomes are needed.