Subcutaneous zalunfiban, an investigational glycoprotein IIb/IIIa (integrin αIIbβ3) inhibitor, significantly improved early coronary reperfusion and reduced the likelihood of worse 30-day clinical outcomes when administered at first medical contact in patients with ST-elevation myocardial infarction (STEMI), according to results from the Phase 2 CELEBRATE trial published in NEJM Evidence.

In the international, double-blind study, 2,467 patients with suspected STEMI were randomised to receive a single pre-hospital injection of zalunfiban (0.11 mg/kg or 0.13 mg/kg) or placebo. Treatment with zalunfiban significantly improved the trial’s hierarchical primary efficacy endpoint, which ranked death, stroke, recurrent myocardial infarction, stent thrombosis, heart failure, infarct size, and absence of events through 30 days (adjusted odds ratio 0.79; 95% CI 0.65–0.98; P=0.028).

Angiographic analyses showed faster coronary blood flow prior to intervention in the zalunfiban groups, with a significantly lower corrected frame count in the infarct-related artery compared with placebo. Rates of GUSTO severe or life-threatening bleeding were similar between groups, although mild-to-moderate bleeding occurred more frequently with zalunfiban.

Zalunfiban was designed for subcutaneous administration in the pre-hospital setting, addressing long-standing limitations of intravenous GP IIb/IIIa inhibitors, which require catheter-lab delivery and specialised monitoring. The findings support the concept that very early platelet inhibition, initiated before hospital arrival, can improve myocardial reperfusion without a corresponding increase in major bleeding risk.

The molecule underlying zalunfiban (RUC-4) was originally discovered at The Rockefeller University. It was identified by Barry S. Coller and colleagues in the university’s Laboratory of Blood and Vascular Biology as a next-generation small-molecule glycoprotein IIb/IIIa (αIIbβ3) inhibitor and later developed clinically by CeleCor Therapeutics, a company Coller co-founded. CeleCor is positioning zalunfiban as a first-in-class, pre-hospital antiplatelet therapy for acute coronary syndromes, with further studies expected to define its role alongside contemporary reperfusion and antithrombotic strategies.