ESOC 2021 | Ischemic benefit vs. hemorrhagic risk in the THALES dual antiplatelet therapy trial
S. Claiborne Johnston, MD, PhD, Dell Medical School, The University of Texas at Austin, Austin, TX, shares an update on the latest risk and benefit findings in the THALES trial, investigating the use of ticagrelor plus aspirin versus aspirin alone in patients with mild-to-moderate acute noncardioembolic ischemic stroke or high-risk transient ischemic attack (TIA). Previously reported primary results demonstrated a reduction of ischemic events with the use of dual antiplatelet therapy, but also an increase in the risk of major hemorrhage. To better understand the benefit and risk findings, net clinical impact was determined, defined as the combination of major ischemic events and major hemorrhage. Net clinical impact favored ticagrelor-aspirin, with a reduction of four major ischemic events for every one increase in major hemorrhage. This interview took place at the European Stroke Organisation Conference (ESOC), 2021.
Transcript (edited for clarity)
We had already published the primary results of the THALES trial and showed that there was a reduction in ischemic events but an increase in hemorrhagic events and there was confusion about that balance, and whether the balance was worthwhile. That the benefits outweighed the risk. And so we went back, and this is according to the regulatory authorities, they were requesting the same thing, and we disentangled the risk and benefit outcomes so that they were truly independent...
We had already published the primary results of the THALES trial and showed that there was a reduction in ischemic events but an increase in hemorrhagic events and there was confusion about that balance, and whether the balance was worthwhile. That the benefits outweighed the risk. And so we went back, and this is according to the regulatory authorities, they were requesting the same thing, and we disentangled the risk and benefit outcomes so that they were truly independent. Made sure they were associated with long-term impact. And then we looked at them in absolute terms so the absolute number that would be expected to be increased or decreased of those two events. And it was critical because people were confused about how to interpret the results.
The original trial showed that the benefits were substantial, in terms of reduction of ischemic events, and the risk of hemorrhage was smaller. And in the disentangled outcomes that we measured here, we found that was, actually, still the case. In fact, a little bit of a stronger effect, where, basically, we had a reduction of four major ischemic events for every one increased major hemorrhage. And that ratio stayed the same, whether we used any disability, or moderate disability, or worse to look at those events. So there wasn’t a difference in levels of disability between those two outcome events.
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Disclosures
Prof. Johnston reports the following disclosures:
My institution has received support from AstraZeneca for research and consulting related to the THALES trial. My institution received drug and placebo from Sanofi for the NIH-sponsored POINT trial.
