Design and rationale of the CLEAR SYNERGY (OASIS 9) trial: A 2x2 factorial randomized controlled trial of colchicine versus placebo and spironolactone vs placebo in patients with myocardial infarction

Background: Patients experiencing myocardial infarction (MI) remain at high risk of future major adverse cardiovascular events (MACE). While low-dose colchicine and spironolactone have been shown to decrease post-MI MACE, more data are required to confirm their safety and efficacy in an unselected post-MI population. Therefore, we initiated the CLEAR SYNERGY (OASIS 9) trial to address these uncertainties.

Methods: The CLEAR SYNERGY trial is a 2 × 2 factorial randomized controlled trial of low-dose colchicine 0.5 mg daily versus placebo and spironolactone 25 mg daily versus placebo in 7,062 post-MI participants who were within 72 hours of the index percutaneous coronary intervention (PCI). We blinded participants, healthcare providers, research personnel, and outcome adjudicators to treatment allocation. The primary outcome for colchicine is the first occurrence of the composite of cardiovascular death, recurrent MI, stroke, or unplanned ischemia-driven revascularization. The coprimary outcomes for spironolactone are (1) the composite of the total numbers of cardiovascular death or new or worsening heart failure and (2) the first occurrence of the composite of cardiovascular death, new or worsening heart failure, recurrent MI or stroke. We finished recruitment with 7,062 participants from 104 centers in 14 countries on November 8, 2022, and plan to present the results in the fall of 2024.

Conclusions: CLEAR SYNERGY is a large international randomized controlled trial that will inform the effects of low-dose colchicine and spironolactone in largely unselected post-MI patients who undergo PCI. (ClinicalTrials.gov Identifier: NCT03048825).