News Release: CLEAR SYNERGY Trial Finds No Cardiovascular Benefit of Colchicine Post-Myocardial Infarction

Introduction: The international CLEAR SYNERGY (OASIS 9) trial investigated the long-term cardiovascular effects of colchicine in patients undergoing percutaneous coronary intervention (PCI) following acute myocardial infarction (MI). Colchicine, an anti-inflammatory agent, had previously shown promise in reducing cardiovascular events in patients with coronary artery disease. This study aimed to evaluate whether colchicine could improve outcomes in a high-risk post-MI population.

Highlights:

• Study Design: Over 7,000 patients with acute MI (95% with STEMI) were enrolled and randomized to receive either colchicine 0.5 mg daily or placebo, in addition to standard care. The trial featured a 2×2 factorial design, also assessing spironolactone versus placebo.
• Primary Outcome: After a median follow-up of 3.5 years, the primary endpoint—a composite of cardiovascular death, MI, stroke, or ischemia-driven revascularization—occurred in 9.1% of the colchicine group and 9.3% of the placebo group (Hazard Ratio [HR] 0.99; 95% Confidence Interval [CI] 0.85-1.16; p=0.93), indicating no significant difference.
• Secondary Outcomes: There were no significant differences in individual components of the primary endpoint, including cardiovascular death (3.3% vs. 3.2%), MI (2.9% vs. 3.1%), or ischemia-driven revascularization (4.6% vs. 4.7%). All-cause mortality was slightly lower in the colchicine group but not statistically significant.
• Safety Profile: Colchicine was associated with a higher incidence of diarrhea (10.2% vs. 6.6%; p<0.001). Serious infections were similar between groups.
• Comparison with Previous Studies: The findings contrast with earlier trials like COLCOT and LoDoCo2, which reported cardiovascular benefits with colchicine in similar patient populations. Possible reasons for the discrepancy include differences in patient characteristics, study design, and the impact of external factors such as the COVID-19 pandemic.

Conclusion: The CLEAR SYNERGY trial concludes that routine use of colchicine following PCI for acute MI does not reduce the risk of major adverse cardiovascular events. These results suggest reevaluating the role of colchicine in post-MI management and may influence future guideline recommendations. Clinicians should consider these findings when prescribing colchicine, balancing the lack of cardiovascular benefit against the potential for gastrointestinal side effects.

Source: This research was conducted by the Population Health Research Institute and presented at the Transcatheter Cardiovascular Therapeutics (TCT) conference on October 29, 2024. Detailed results are available through the American College of Cardiology (https://www.acc.org/Latest-in-Cardiology/Clinical-Trials/2024/10/25/04/34/clear-synergy) and TCTMD (https://www.tctmd.com/news/colchicine-surprise-no-help-post-mi-large-clear-synergy-trial-shows).