Conference Coverage

The TWILIGHT of aspirin post-PCI for ACS?


 

REPORTING FROM AHA 2019

– Downshifting to ticagrelor monotherapy after just 3 months of dual antiplatelet therapy is a winning strategy in high-risk patients who’ve undergone PCI for non-ST-elevation acute coronary syndrome, Usman Baber, MD, reported at the American Heart Association scientific sessions.

Dr. Usman Baber, a cardiologist at Icahn School of Medicine, New York Bruce Jancin/MDedge News

Dr. Usman Baber

He presented a prespecified subgroup analysis of the previously reported TWILIGHT study that was restricted to the 4,614 participants with non-ST-elevation ACS who underwent PCI, completed 3 months of dual antiplatelet therapy (DAPT) with ticagrelor and aspirin, and were then randomized double-blind to an additional 12 months on the same regimen or to ticagrelor plus placebo.

The key finding: After a year on ticagrelor monotherapy, the risk of clinically significant or major bleeding was reduced by 53%, compared with the DAPT group, and with no increased risk of ischemic major adverse cardiovascular events, said Dr. Baber, a cardiologist at the Icahn School of Medicine at Mount Sinai, New York.

This secondary analysis of the TWILIGHT study was carried out because none of the several prior studies of short-term DAPT followed by an aspirin-free strategy after PCI was double-blind. Nor did any include patients with non-ST-elevation ACS, he explained.

The TWILIGHT substudy included 2,494 participants with unstable angina and 2,120 with non-ST-elevation MI. Roughly two-thirds had four or more high-risk clinical or angiographic features, such as diabetes, chronic kidney disease, multivessel CAD, or left main lesions.

The primary study endpoint at month 15 – the rate of Bleeding Academic Research Consortium (BARC) type 2, 3, or 5 bleeding events – was 7.6% with ticagrelor plus aspirin, compared with 3.6% with ticagrelor plus placebo, for a highly significant 53% relative risk reduction in favor of ticagrelor monotherapy. The key secondary endpoint, a composite of all-cause mortality, MI, or stroke, occurred in roughly 4.4% of patients in each study arm.

Of note, ticagrelor monotherapy after 3 months of DAPT was associated with a similar 50%-60% reduction in the risk of BARC 2, 3, or 5 bleeding regardless of whether patients had 1-3, 4 or 5, or 6-9 prespecified high-risk clinical and angiographic features. Nor was the impact of ticagrelor monotherapy on ischemic events impacted by risk factor burden.

Discussant Michelle L. O’Donoghue, MD, observed that while the current practice of most cardiologists in patients undergoing stenting in the setting of ACS is 12 months of DAPT followed by discontinuation of the P2Y12 inhibitor and indefinite continuation of aspirin, mounting evidence suggests there’s a better approach.

Dr. Michelle L. O'Donoghue, cardiologist at Brigham and Women's Hospital and Harvard Medical School, Boston Bruce Jancin/MDedge News

Dr. Michelle L. O'Donoghue

Indeed, the new TWILIGHT findings in patients with non-ST-elevation ACS dovetail nicely with the results of three other recent studies of discontinuing aspirin after 1-3 months versus continuing DAPT with ticagrelor or another P2Y12 inhibitor plus aspirin. These studies, GLOBAL LEADERS (Lancet. 2018 Sep 15;392[10151]:940-9); SMART CHOICE (JAMA. 2019 Jun 25;321[24]:2428-37); and STOPDAPT-2 (JAMA. 2019 Jun 25;321[24]:2414-27) included patients undergoing PCI either for stable coronary disease or for ST-elevation MI, but not for non-ST-elevation ACS.

Dr. O’Donoghue, a cardiologist at Brigham and Women’s Hospital and Harvard Medical School, Boston, conducted a meta-analysis including the TWILIGHT ACS trial and the other three studies. In a total population of 29,205 patients, a strategy of dropping aspirin while continuing a P2Y12 inhibitor after 1-3 months of DAPT was associated with a 40% relative risk reduction in major bleeding events when compared with continued DAPT, with no indication of an increased risk of major adverse cardiovascular events. When she looked specifically at the nearly 14,000 post-ACS patients in the studies, the same consistency with respect to outcomes held true: an overall 51% reduction in bleeding, and – if anything – a favorable trend involving an 11% reduction in the risk of major adverse cardiovascular events, although this difference didn’t reach statistical significance.

“I believe that discontinuation of aspirin markedly reduces bleeding when stopped 1-3 months post PCI for patients initially started on DAPT,” Dr. O’Donoghue declared. “The evidence to date does not indicate that stopping aspirin leads to any increase in the risk of major adverse cardiovascular events. And these findings now extend to patients with ACS, including those with high-risk clinical and angiographic features.”

The important remaining questions, she added, include the best-choice P2Y12 inhibitor for early monotherapy post-PCI, whether the medication should be continued indefinitely past the 12-month mark, and whether aspirin might be safely discontinued even earlier than at 1-3 months.

“If you are thinking about establishing a clopidogrel monotherapy, you need to keep in mind that there exists significant interpatient variability in terms of pharmacodynamic response,” she noted, adding that platelet function testing or genotyping to identify clopidogrel resistance is worth considering in such patients.

The primary results of the full TWILIGHT study, which included 7,119 randomized patients, have been published (N Engl J Med. 2019 Sep 26. doi: 10.1056/NEJMoa1908419).

The TWILIGHT study was sponsored by AstraZeneca. Dr. Baber reported receiving honoraria from that company as well as Boston Scientific.

Dr. O’Donoghue reported receiving institutional research support from a handful of pharmaceutical companies.

SOURCE: Baber U. AHA late breaker.

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