Ticagrelor-aspirin treatment effect in THALES strongest in ipsilateral stenosis
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In new data from the THALES trial of patients with prior stroke, the benefit of ticagrelor plus aspirin for secondary stroke prevention was greatest in those with ipsilateral atherosclerotic stenosis.
However, there was no interaction for the effect of ticagrelor (Brilinta, AstraZeneca) plus aspirin on stroke or death compared with aspirin alone between patients with and without ipsilateral atherosclerotic stenosis.
As Healio previously reported, in the main results of THALES, patients with minor stroke or high-risk transient ischemic attack assigned aspirin plus ticagrelor had reduced risk for stroke or death at 30 days compared with those assigned aspirin plus placebo. Based on those results, the FDA granted a new indication for secondary stroke prevention to ticagrelor.
Pierre Amarenco, MD, professor of neurology at the University of Paris and chair of the department of neurology, the Stroke Centre and the TIA Clinic at Bichat Hospital in Paris, presented an analysis of the results stratified by whether patients had ipsilateral atherosclerotic stenosis at the virtual American Heart Association Scientific Sessions. The analysis was simultaneously published in Stroke.
Among patients with ipsilateral atherosclerotic stenosis (n = 2,351; mean age, 67 years; 32% women), 7.9% of those assigned ticagrelor plus aspirin died or had a stroke at 30 days compared with 10.9% of those assigned aspirin alone (HR = 0.73; 95% CI, 0.56-0.96; P = .023; number needed to treat = 34), whereas among those without ipsilateral stenosis, 4.8% of those assigned ticagrelor plus aspirin met the primary endpoint vs. 5.3% of those assigned aspirin alone (HR = 0.89; 95% CI, 0.74-1.08; P = .23), Amarenco said at a press conference.
“The risk in the atherosclerotic group was double the risk of those without atherosclerotic disease,” he said. “However, the interaction was not significant, meaning that the overall result which we saw in the THALES trial also applies to the non-ipsilateral stenosis group.” The P value for interaction was .245.
In patients with ipsilateral stenosis, the ticagrelor-aspirin group had reduced risk for ischemic stroke (HR = 0.72; 95% CI, 0.55-0.95; P = .02), any stroke (HR = 0.72; 95% CI, 95% CI, 0.55-0.94; P = .02) and disabling stroke (HR = 0.72; 95% CI, 0.53-0.98; P = .038), and there was no significant interaction for those outcomes compared with patients without ipsilateral stenosis, Amarenco said.
In both those with and without ipsilateral stenosis, there was no difference between the treatment arms in 30-day death, he said.
GUSTO severe bleeding was more common in patients without ipsilateral stenosis than in those with it. In those without ipsilateral stenosis, the ticagrelor-aspirin group had elevated risk for severe bleeding (HR = 5.87; 95% CI, 2.04-16.9; P = .001).
The results are “concordant with prior studies suggesting that atherosclerotic disease carries a greater risk than other stroke subtypes without stenosis among patients with TIA or a minor ischemic stroke event on aspirin,” Amarenco said during the press conference. “Given both the SOCRATES and THALES results, targeting patients with atherosclerotic stenosis for dual therapy with ticagrelor and aspirin could yield a clinically meaningful relative and absolute risk reduction of stroke and death as compared to aspirin alone, with a number needed to treat of 34 and a number needed to harm of 951.”
“It’s clear that there is added benefit in patients with carotid atherosclerosis,” Louise McCullough, MD, PhD, Huffington Chair of Neurology at McGovern Medical School at UTHealth, said in a discussion during the press conference. “Would that benefit be greater than carotid revascularization? What about patients treated with [tissue plasminogen activator]? Those were excluded, as were patients who had thrombectomy. Is ticagrelor better than clopidogrel? It certainly seems this regimen could be a very good choice with atherosclerosis, just like clopidogrel may be a good choice in patients with peripheral vascular disease.”
Reference:
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Amarenco P, et al. LBS.07: Randomized trials – Brain, kidney and heart. Presented at: American Heart Association Scientific Sessions; Nov. 13-17, 2020 (virtual meeting).
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