Discussant Gilles Montalescot, MD, PhD, called ISAR-REACT 5 a “fascinating” study. He elaborated: “It is a pragmatic study to answer a pragmatic question. It’s not a drug trial; really, it’s more a strategy trial, with a comparison of two drugs and two strategies.”
Bruce Jancin/MDedge News
Dr. Gilles Montalescot
In ISAR-REACT 5, ticagrelor was utilized in standard fashion: Patients, regardless of their ACS type, received a 180-mg loading dose as soon as possible after randomization, typically about 3 hours after presentation. That was also the protocol in the prasugrel arm, but only in patients with STEMI, who quickly got a 60-mg loading dose. In contrast, patients without STEMI or with unstable angina didn’t get a loading dose of prasugrel until they’d undergone coronary angiography and their coronary anatomy was known. That was the ISAR-REACT 5 strategy in light of an earlier study, which concluded that giving prasugrel prior to angiography in such patients led to increased bleeding without any improvement in clinical outcomes.
The essence of ISAR-REACT 5 lies in that difference in treatment strategies and the impact it had on outcomes. “The one-size-fits-all strategy – here, with ticagrelor – was inferior to an individualized strategy, here with prasugrel,” observed Dr. Montalescot, professor of cardiology at the University of Paris VI and director of the cardiac care unit at Paris-Salpetriere Hospital.
The study results were notably consistent, favoring prasugrel over ticagrelor numerically across the board regardless of whether a patient presented with STEMI, without STEMI, or with unstable angina. Particularly noteworthy was the finding that this was also true in terms of the individual components of the 1-year composite endpoint. Dr. Montalescot drew special attention to the large subset of patients who had presented with STEMI and thus received the same treatment strategy involving a loading dose of their assigned P2Y12 inhibitor prior to angiography. This allowed for a direct head-to-head comparison of the clinical efficacy of the two antiplatelet agents in STEMI patients. The clear winner here was prasugrel, as the composite event rate was 10.1% in the ticagrelor group, compared with 7.9% in the prasugrel group.
“ISAR-REACT 5 is a landmark study which is going to impact our practice and the next set of guidelines to come in 2020,” the interventional cardiologist predicted.
Dr. Schuepke reported having no financial conflicts regarding the ISAR-REACT 5 study, sponsored by the German Heart Center and the German Center for Cardiovascular Research.
Simultaneous with her presentation of ISAR-REACT 5, the study results were published online (N Engl J Med. 2019 Sep 1. doi: 10.1056/NEJMoa1908973).