Crucial questions remain
NEW ORLEANS – In STEMI patients who aren’t able to undergo primary PCI, ticagrelor after fibrinolytic therapy offered no advantages over clopidogrel – a less potent and less costly antiplatelet agent – in rates of cardiovascular events or bleeding though 12 months of follow-up in the TREAT trial.
Bruce Jancin/MDedge News
Dr. Otavio Berwanger
“In terms of efficacy, it is appropriate to interpret TREAT statistically as a neutral trial,” Otavio Berwanger, MD, PhD, advised at the annual meeting of the American College of Cardiology.
TREAT (Ticagrelor in patients with ST-elevation myocardial infarction treated with pharmacological thrombolysis) was a 10-country, 152-site, randomized, open-label clinical trial of 3,799 STEMI (ST-elevation MI) patients treated with fibrinolytic therapy followed an average of 11 hours later by a loading dose of either ticagrelor (Brilinta) or clopidogrel, then 12 months of standard-dose maintenance therapy of their designated potent antiplatelet drug. The adherence rate was 90% at 12 months. Participating countries included Russia, China, Brazil, Australia, and Canada, but not the United States.
The primary efficacy endpoint was the 12-month composite of death from a vascular cause, MI, stroke, severe recurrent ischemia, TIA, or another arterial thrombotic event. The rate was 8% in the ticagrelor group and 9.1% with clopidogrel, a 12% relative risk reduction in favor of ticagrelor that was not statistically significant. But then, TREAT was underpowered to show a difference in efficacy. However, the 12% relative risk reduction mirrors that seen in the earlier PLATO trial of 18,624 patients with acute coronary syndrome who were randomized to ticagrelor or clopidogrel in conjunction with primary PCI, a difference that was statistically significant because of PLATO’s much larger size (N Engl J Med. 2009 Sep 10;361[11]:1045-57).
TREAT was sufficiently powered to assess safety. There was no significant between-group difference in TIMI major bleeding, the primary safety endpoint. However, the rate of total bleeding events was significantly higher in the ticagrelor arm, by a margin of 10.25% versus 6.15%. Moreover, the rate of TIMI clinically significant bleeding requiring medical attention was also higher in the ticagrelor group – 5.2% versus 3.8% – and the TIMI minimal bleeding rate of 5.85% in the ticagrelor group was more than double that in the clopidogrel arm, reported Dr. Berwanger of the Heart Hospital Research Institute in São Paolo.
These 12-month outcomes echo those previously reported at the 30-day mark in TREAT (JAMA Cardiol. 2018 May 1;3[5]:391-9).
Discussant C. Michael Gibson, MD, put TREAT in perspective: “Here we’re looking to see if there are differences between two thienopyridine inhibitors. There’s nothing really that important on the efficacy side, although there was 1.5% missingness in the study. And there was a higher number of total bleeds with ticagrelor.
“Some of the junior members of the audience may not be all that familiar with fibrinolysis. In the era where it was more prominent, reocclusion occurred in 5%-8% of patients. When it did occur, it led to a tripling of mortality. It’s important to note that the first study of a thienopyridine inhibitor added to lytics was CLARITY, almost 15 years ago, showing a reduction in death, MI, or reocclusion down from about 15% to 7% [N Engl J Med 2005; 352:1179-89]. So it should be very clear to the audience that reocclusion is a problem and the addition of a thienopyridine inhibitor improves that,” explained Dr. Gibson, professor of medicine at Harvard Medical School, Boston.
The TREAT trial was funded by AstraZeneca. Dr. Berwanger reported receiving research grants from and serving as a consultant to that company and half a dozen others.
Simultaneously with the presentation, the TREAT study was published online (J Am Coll Cardiol. 2019 Mar 12. doi: 10.1016/j.jacc.2019.03.011).