Post-PCI, clopidogrel monotherapy after 1 month reduces bleeding risk vs. 12-month DAPT
In a pooled cohort of the two STOPDAPT-2 trials, among patients who underwent PCI, switching from dual antiplatelet therapy to clopidogrel monotherapy after 1 month reduced bleeding risk compared with 12-month DAPT.
Clopidogrel monotherapy after 1 month was noninferior to 12-month DAPT for ischemic events and a composite of ischemic and bleeding events, according to a presentation at TCT 2021.
The analysis included 5,997 patients from the STOPDAPT-2 and STOPDAPT-2 ACS trials who were randomly assigned 1-month DAPT followed by clopidogrel monotherapy or 12-month DAPT after PCI with an everolimus-eluting stent (Xience series, Abbott).
“In the STOPDAPT-2 trial, clopidogrel monotherapy after 1-month DAPT was demonstrated to be noninferior to 12-month DAPT with aspirin and clopidogrel in terms of net clinical benefit, while it was inconclusive in the pooled ACS population from the STOPDAPT-2 and the STOPDAPT-2 ACS trials. However, given the event rates lower than anticipated, both the STOPDAPT-2 and STOPDAPT-2 ACS trials were underpowered,” Yuki Obayashi, MD, from Kyoto University Graduate School of Medicine in Japan, said during a press conference. “We sought to evaluate the safety and efficacy of clopidogrel monotherapy after 1-month DAPT relative to 12-month DAPT in the STOPDAPT-2 Total Cohort (the pooled population of the STOPDAPT-2 and the STOPDAPT-2 ACS) with an increased power, and to explore the treatment-by-subgroup interaction for ACS, [high bleeding risk] and complex PCI.”
The primary composite endpoint of CV death, MI, stroke, definite stent thrombosis and TIMI major or minor bleeding occurred in 2.84% of the 1-month DAPT group and 3.04% of the 12-month DAPT group at 1 year (HR = 0.94; 95% CI, 0.7-1.27; P for noninferiority = .001; P for superiority = .68), Obayashi said during the press conference.
The major secondary CV endpoint of CV death, MI, stroke and definite stent thrombosis occurred in 2.4% of the 1-month DAPT group and 1.97% of the 12-month DAPT group (HR = 1.24; 95% CI, 0.88-1.75), Obayashi said. However, he said, for the major secondary bleeding endpoint of TIMI major or minor bleeding, the 1-month DAPT group had a significantly lower rate than the 12-month DAPT group (0.5% vs. 1.31%; HR = 0.38; 95% CI, 0.21-0.7).
In a subgroup analysis comparing patients with ACS and patients with chronic coronary syndrome, there was no between-group interaction for the primary composite endpoint (P for interaction = .052), the major secondary CV endpoint (P for interaction = .08) and the major secondary bleeding endpoint (P for interaction = .4), though for both the primary endpoint and the major secondary CV endpoint, there was more favorability for the 1-month DAPT strategy in patients with chronic coronary syndrome, Obayashi said.
“The treatment-by-subgroup interaction was not significant for ACS and [chronic coronary syndrome],” he said during the press conference. “However, given a numerical increase in cardiovascular events with clopidogrel monotherapy after 1-month DAPT in ACS patients, further studies would be warranted to explore the optimal antithrombotic strategies in ACS patients.”
There was no interaction for any of the endpoints according to whether patients were at high bleeding risk or not, Ko Yamamoto, MD, also from Kyoto University Graduate School of Medicine, said during the press conference.
“The effects of 1-month DAPT relative to 12-month DAPT for cardiovascular and bleeding events were consistent regardless of bleeding risk,” Yamamoto said. “Nevertheless, the absolute benefit of 1-month DAPT relative to 12-month DAPT in reducing major bleeding was numerically greater in [high bleeding risk] patients than in non-[high bleeding risk] patients.”
There was also no interaction for any endpoint according to whether a patient underwent complex PCI or not, Yamamoto said during the press conference.
“The effects of 1-month DAPT relative to 12-month DAPT for cardiovascular and bleeding events were consistent regardless of complex PCI,” he said. “Complex PCI might not be an appropriate determinant for DAPT durations after PCI.”
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Obayashi Y, et al. Late-Breaking Clinical Science Session II, in Collaboration with The European Heart Journal. Presented at: TCT Scientific Symposium; Nov. 4-6, 2021; Orlando (hybrid meeting).