Dual Antiplatelet TOPIC study

Benefit of switching dual antiplatelet therapy after acute coronary syndrome: the TOPIC (timing of platelet inhibition after acute coronary syndrome) randomized study  

European Heart Journal (2017)  doi:10.1093/eurheartj/ehx175

Objective: To evaluate the benefit of switching dual antiplatelet therapy (DAPT) from aspirin plus a newer P2Y12 blocker (ticagrelor/prasugrel) to aspirin plus clopidogrel 1 month after ACS.

Methods:

  • An open-label, monocentric, and randomized trial at Timone Hospital, Marseille, France.
  • 646 patients (admitted with ACS requiring PCI, on aspirin and a newer P2Y12 blocker and without adverse event at 1 month) were randomised to switch to aspirin and clopidogrel (switched DAPT, n=323) or continuation of their drug regimen (unchanged DAPT, n=323).
  • The primary outcome : A composite of cardiovascular death, urgent revascularization, stroke and bleeding Bleeding Academic Research Consortium (BARC) >2 at 1 year
    post ACS. This combination of both ischaemic and bleeding events was defined as “net clinical benefit”.
  • Follow up : 1 year

Results:

  •  1 year follow up was performed for 316 (98.1%) patients in the switched DAPT group and 318 (98.5%) in the unchanged DAPT group. Median Duration: 359 days
  • Mean Age: 60 years. 43% patients were on ticagrelor, 57% on prasugrel.
  • 40% patients had STEMI, 60% had either unstable angina or NSTEMI
  • Drug Eluting Stents were used in 91% patients, 96% PCI done by radial route
  • The rate of primary endpoint (“Net Clinical Benefit”) was significantly less in switched DAPT group (13.4%) Vs unchanged DAPT group 26.3% (HR 95%CI 0.48 (0.34–0.68),
    P< 0.01) (Figure below)

  • No difference in both groups for ischemic events (switched DAPT Vs Unchanged DAPT ; 9.3% Vs 11.5%, P=0.36)
  • BARC Bleedings > 2 was 70% lower in switched DAPT group (4%) Vs Unchanged DAPT group (14.9%) p < 0.01
  • No difference between both groups for unplanned revascularization, TIMI major bleeding,
  • No difference between both groups for stent thrombosis, CV death and stroke (events very less)
  • All end points are mentioned in the table below

Conclusion:

In patients on aspirin + ticagrelor/prasugrel without an adverse event in 1st month following an ACS treated with PCI, switching DAPT  to aspirin + clopidogrel may reduce the risk of bleeding recurrence without increased risk of ischaemic events.

Limitations of the study

  • Single Center, open label study
  • Study size was small and not decisive for Stent Thrombosis or Total Mortality

Link to article

https://academic.oup.com/eurheartj/article/3827697/Benefit-of-switching-dual-antiplatelet-therapy