Abstract Body (Do not enter title and authors here): Background
Zalunfiban is a subcutaneous glycoprotein IIb/IIIa inhibitor developed for administration at first medical contact in patients with ST segment elevation myocardial infarction (STEMI) intended to undergo primary percutaneous coronary intervention. Whether its use improves clinical outcomes remains unknown.

Methods
We conducted an international, randomized, double-blind, placebo-controlled trial involving participants with STEMI and symptom onset within 4 hours. Participants were randomly assigned in a 1:1:1 ratio to receive a single subcutaneous dose of zalunfiban (0.11 mg/kg or 0.13 mg/kg) or placebo at first medical contact. The primary efficacy end point was a seven-point hierarchically ranked clinical composite 30 day outcome: all-cause death, stroke, recurrent myocardial infarction, acute stent thrombosis, new-onset heart failure or rehospitalization for heart failure, infarct size or no event. Odds ratios adjusted for prespecified risk factors were used to compare the pooled zalunfiban groups with placebo (See Figure Design)

Results
A total of 2465 participants underwent randomization and were either assigned to zalunfiban 0.11mg/kg, to zalunfiban 0.13 mg/kg or to placebo. Inclusion was complete on May 13, 2025. Database lock is expected the end of August 2025. Results of the primary efficacy, primary safety and key secondary outcome measures will be presented at the meeting.

Funding
Funded by CeleCor Therapeutics, ClinicalTrials.gov number, NCT04825743