No Significant Benefit With Colchicine Addition in Acute Myocardial Infarction

Acute and long-term colchicine use in acute myocardial infarction (MI) did not reduce cardiovascular death, MI, stroke, or ischemia-driven revascularization, according to results of the CLEAR SYNEGRY (OASIS 9) trial.

CLEAR SYNERGY is the largest trial examining the effect of colchicine for acute MI, and results were presented by study principle investigator Sanjit S. Jolly MD, MSc, at the Transcatheter Cardiovascular Therapeutics (TCT) 2024 annual scientific symposium of the Cardiovascular Research Foundation on October 29.

The study cohort comprised 7,062 participants with ST elevation MI (STEMI) or large non-STEMI (NSTEMI) across 14 countries and 104 treatment sites. Participants were randomly assigned within 72 hours of percutaneous coronary intervention to either colchicine or placebo; both cohorts were then randomly assigned to receive spironolactone or placebo.

Characteristics were similar across both cohorts: The mean age was 60.6 years, 18% had diabetes, and 9% had prior MI.

The trial was designed with 80% power to detect a 25% relative risk reduction in the primary outcome as assessed using a Cox proportional hazards model stratified by STEMI versus NSTEMI and spironolactone versus placebo.

At three-years median follow-up, the composite of cardiovascular death, recurrent MI, stroke, or ischemia-driven revascularization was not significantly different between the colchicine and placebo groups (9.1% vs 9.3%; hazard ratio [HR], 0.99; 95% CI, 0.85-1.16; P=.93).

There were no significant differences in any of the individual components of the composite endpoint. However, a significant reduction in C-reactive protein—an inflammation marker—was observed in the colchicine-receiving group. Adverse events were similar in both groups except that diarrhea was more common with colchicine than with placebo (10.2% vs 6.6%; P>.001).

“As the largest trial to date on this subject (649 outcome events), with significantly more events than previous studies, colchicine did not provide a significant benefit and its role in long-term post myocardial infarction use is uncertain,” Dr. Jolly concluded.