CeleBrate: Zalunfiban Administration at First Contact Improves STEMI Outcomes, With C. Michael Gibson, MD

Zalunfiban, a subcutaneous glycoprotein (GP) IIb/IIIa inhibitor in development by CeleCor Therapeutics for administration at first contact to patients with suspected ST-segment elevation myocardial infarction (STEMI), has met its primary efficacy and safety endpoints in the pivotal CeleBrate phase 3 trial.1

GPIIb/IIIa inhibitors are the most potent antiplatelet drugs, blocking platelet aggregation induced by all activators including thrombin, thromboxane A2, and ADP. Most GPIIb/IIIa inhibitors must be delivered by an intravenous injection followed by continuous intravenous delivery with an infusion pump. However, zalunfiban can be administered rapidly – during the CeleBrate trial, patients received the medication at home, in the ambulance, or at a hospital emergency department.1

The editorial team at HCPLive met with C. Michael Gibson, MD, an interventional cardiologist and the chief executive officer of the combined non-profit Baim and PERFUSE research institutes at Harvard Medical School, to discuss the implications of these data for the historically poor mortality rates in STEMI.

“When someone gets to the hospital, we do a great job getting them to the catheterization lab. It’s that time before they reach the hospital where we’re not doing as good of a job,” Gibson told HCPLive. “Sadly, about half the deaths from heart attacks occur before someone even reaches the hospital. So, our goal was to really get the ball moving before someone hits the hospital door.”

CeleBrate is a phase 3, prospective, blinded, randomized, placebo-controlled, international multicenter study conducted at 45 locations worldwide. Patients were screened in the ambulance based on available information; male patients aged ≥18 years and post-menopausal females ≥50 years, weighing between 52 and 130 kg and with STEMI presenting with persistent ischemic chest pain (>10 minutes) and new ≥2 mm ST-segment elevation in 2 adjacent ECG leads within 4 hours were eligible for inclusion. Patients who had systolic blood pressure <90 mmHg and heart rate >100 bpm, who were being currently treated with renal dialysis, oral anticoagulation, direct oral anticoagulants, or thrombolytic agents, or who had a known history of ischemic or hemorrhagic stroke or severe anemia were excluded.2

Patients enrolled in the trial were randomly assigned in a 1:1:1 ratio to a single subcutaneous dose of zalunfiban 0.11 mg/kg or 0.13 mg/kg, or placebo. The primary efficacy endpoint was a hierarchical proportional odds model ranking 7 endpoints from worst to best. These included all-cause death, stroke, recurrent myocardial infarction, acute stent thrombosis, new-onset or re-hospitalization for heart failure, larger infarct size, or no endpoint through 30 days.3

Ultimately, 2467 patients were included in the trial, with 853 receiving zalunfiban 0.11 mg/kg, 818 receiving zalunfiban 0.13 mg/kg, and 796 receiving placebo. The primary efficacy endpoint was substantially improved in the zalunfiban arm (adjusted odds ratio [OR], 0.79; 95% CI, 0.65-0.98; P = .028). Additionally, investigators observed no difference in the primary safety endpoint of GUSTO severe bleeding (1.2% vs 0.8%; P = .4); however, GUSTO mild to moderate bleeding was increased (6.4% vs 2.5%), as was access site bleeding (9.4% vs 4.4%). Coronary blood flow was significantly faster in the zalunfiban treated groups on arrival to the cardiac catheterization laboratory (median 109 vs 176 frames, P = .012).3

“A lot of people show up at a hospital that’s not equipped to do primary PCI, and they must be transferred. That often takes more than 2 hours from when they had symptoms,” Gibson said. “We’re not meeting the guideline recommendations in >80% of patients. This drug could really help improve outcomes in those patients, because it can increase the odds that the artery will be opened while you transfer that patient.”

In a press release regarding the study, CeleCor Therapeutics announced their intent to file a New Drug Application for zalunfiban with the US Food and Drug Administration in early 2026.2

References

1. CeleCor Therapeutics. Rapid zalunfiban treatment at 1st point of medical contact lowered risk of more severe heart damage in combination with other serious heart-attack complications. November 10, 2025. Accessed December 2, 2025. https://www.celecor.com/rapid-zalunfiban-treatment-at-1st-point-of-medical-contact-lowered-risk-of-more-severe-heart-damage-in-combination-with-other-serious-heart-attack-complications/

2. van ‘t Hof A, Gibson CM, Rikken S, et al. Zalunfiban at First Medical Contact in Patients with ST-Segment Elevation Myocardial Infarction. Presented at the American Heart Association’s Scientific Sessions 2025. New Orleans, Louisiana. November 8-10, 2025.

3. CeleCor Therapeutics. A Phase 3 Study of Zalunfiban in Subjects With ST-elevation MI (CELEBRATE). ClinicalTrials.gov Identifier: NCT04825743. Updated October 23, 2025. Accessed December 2, 2025. https://www.clinicaltrials.gov/study/NCT04825743