ITALIC Shows Noninferiority of 6-Month DAPT in Good Aspirin Responders

CHICAGO, IL—Patients implanted with newer-generation drug-eluting stents (DES) can expect no difference in bleeding and thrombotic events whether they receive 6 or 24 months of dual antiplatelet therapy (DAPT), according to results of the ITALIC/ITALIC+ study presented on November 16, 2014, at the American Heart Association Scientific Sessions. Results also demonstrated the noninferiority of shorter treatment in patients both with and without acute coronary syndromes (ACS).

The study was simultaneously published in the Journal of the American College of Cardiology.

Martine Gilard, MD, PhD, of CHU de la Cavale Blanch (Brest, France), and colleagues enrolled 2,031 patients who had previously undergone PCI with at least 1 Xience V DES (Abbott Vascular) at 70 sites in Europe and the Middle East from November 2008 to November 2013. Patients were pretreated with aspirin and clopidogrel. While good aspirin responders (n = 1,894) were randomized to 6 months (n = 953) or 24 months (n = 941) of DAPT (99% clopidogrel) followed by aspirin alone, those with aspirin resistance (n = 137) were treated with DAPT at a duration decided upon by their clinician. 

Procedural success was achieved in 99% of patients, and slightly less than half were treated for more than 1 lesion. One-quarter of patients in the short-term treatment arm did not adhere to 6 months of therapy, with 8.9% continuing treatment longer. Of the long-term arm, only 5.4% discontinued treatment before 24 months.

Among aspirin responders, the primary composite endpoint (death, MI, emergency TVR, stroke, or TIMI major bleeding within 12 months) was similar between the study groups. There were also no differences in major or minor bleeding, stent thrombosis, or any of the individual components of the primary endpoint (table 1). Hence, noninferiority criteria were met for 6- vs 24-month DAPT (0.11%; 95% CI: -1.04 to 1.26; P for noninferiority = .0002). 

Results were confirmed in subgroups of patients both with and without ACS (P for interaction = .305). 

The trial was prematurely terminated due to low enrollment. However, the event rate was half of what was originally predicted (3%). 

In commentary following the presentation, Gilles Montalescot, MD, PhD, of Pitié-Salpêtrière Hospital (Paris, France), said results from ITALIC “tell us these studies are difficult to conduct and no study itself is conclusive.” However, he added, it will add to the growing body of data that will help clinicians make appropriate decisions for their patients.

Event Rates ‘Very Low’ Even with Aspirin Resistance 

“Crossover from dual to single antiplatelet therapy after 6 months is possible in good aspirin responders. However, in the present aspirin-resistant group, the rate of adverse events was also very low,” Dr. Gilard and colleagues write, citing the 1.5% overall event rate and individual event rates similar to those of the randomized groups.

This was “probably due to over-treatment of patients known to be resistant to aspirin. The role of ASA resistance monitoring in clinical practice should be questioned,” they add.
  

Source:
Gilard M, Barragan P, Al Noryani A, et al. Six-month versus 24-month dual antiplatelet therapy after implantation of drug eluting stents in patients non-resistant to aspirin: ITALIC, a randomized multicenter trial. J Am Coll Cardiol. 2014;Epub ahead of print.

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