Prehospital treatment with zalunfiban (RUC-4) in patients with ST- elevation myocardial infarction undergoing primary percutaneous coronary intervention: Rationale and design of the CELEBRATE trial.

BACKGROUND: Early and complete restoration of target vessel patency in ST-elevation myocardial infarction (STEMI) is associated with improved outcomes. Oral P2Y12 inhibitors have failed to demonstrate either improved patency or reduced mortality when administered in the prehospital setting. Thus, there is a need for antiplatelet agents that achieve prompt and potent platelet inhibition, and that restore patency in the prehospital setting. Zalunfiban, a novel subcutaneously administered glycoprotein IIb/IIIa inhibitor designed for prehospital administration, has shown to achieve rapid, high-grade platelet inhibition that exceeds that of P2Y12 inhibitors. Whether prehospital administration of zalunfiban can improve clinical outcome is unknown. HYPOTHESIS: The present study is designed to assess the hypothesis that a single, prehospital injection of zalunfiban given in the ambulance, in addition to standard-of-care in patients with STEMI with intent to undergo primary percutaneous coronary intervention (PCI) will improve clinical outcome compared to standard-of-care with placebo. STUDY DESIGN: The ongoing CELEBRATE trial (NCT04825743) is a phase 3, randomized, double-blinded, placebo-controlled, international trial. Patients with STEMI intended to undergo primary PCI will receive treatment with a single subcutaneous injection containing either zalunfiban dose 1 (0.110 mg/kg), zalunfiban dose 2 (0.130 mg/kg) or placebo, and the study drug will be administered in the ambulance before transportation to the hospital. A target of 2499 patients will be randomly assigned to one of the treatment groups in a 1:1:1 ratio, ie, to have approximately 833 evaluable patients per group. The primary efficacy outcome is a ranked 7-point scale on clinical outcomes. The primary safety outcome is severe or life-threatening bleeding according to the Global Use of Strategies to Open Occluded Coronary Arteries (GUSTO) criteria. SUMMARY: The CELEBRATE trial will assess whether a single prehospital subcutaneous injection of zalunfiban in addition to standard-of-care in patients with STEMI with intent to undergo primary PCI will result in improved clinical outcome.

Prepercutaneous coronary intervention Zalunfiban dose-response relationship to target vessel blood flow at initial angiogram in st-elevation myocardial infarction - A post hoc analysis of the cel-02 phase IIa study.

BACKGROUND: Zalunfiban (RUC-4) is a novel, subcutaneously administered glycoprotein IIb/IIIa inhibitor (GPI) designed for prehospital treatment to initiate reperfusion in the infarct-related artery (IRA) before primary percutaneous coronary intervention in patients with ST-elevation myocardial infarction (STEMI). Since GPIs have been reported to rapidly reperfuse IRAs, we assessed whether there was a dose-dependent relationship between zalunfiban treatment and angiographic reperfusion indices and thrombus grade of the IRA at initial angiogram in patients with STEMI. METHODS: This was a post hoc analysis from the open-label Phase IIa study that investigated the pharmacodynamics, pharmacokinetics, and tolerability of three doses of zalunfiban - 0.075, 0.090 and 0.110 mg/kg - in STEMI patients. This analysis explored dose-dependent associations between zalunfiban and three angiographic indices of the IRA, namely coronary and myocardial blood flow and thrombus burden. Zalunfiban was administered in the cardiac catheterization laboratory prior to vascular access, ∼10 to 15 minutes before the initial angiogram. All angiographic data were analyzed by a blinded, independent, core laboratory. RESULTS: Twentyfour out of 27 STEMI patients were evaluable for angiographic analysis (0.075 mg/kg [n=7], 0.090 mg/kg [n=9], and 0.110 mg/kg [n=8]). TIMI flow grade 2 or 3 was seen in 1/7 patients receiving zalunfiban at 0.075 mg/kg, in 6/9 patients receiving 0.090 mg/kg, and in 7/8 patients receiving 0.110 mg/kg (ptrend = 0.004). A similar trend was observed based on TIMI flow grade 3. Myocardial perfusion was also related to zalunfiban dose (ptrend = 0.005) as reflected by more frequent TIMI myocardial perfusion grade 3. Consistent with the dose-dependent trends in greater coronary and myocardial perfusion, TIMI thrombus ≥4 grade was inversely related to zalunfiban dose (ptrend = 0.02). CONCLUSION: This post hoc analysis found that higher doses of zalunfiban administered in the cardiac catheterization lab prior to vascular access were associated with greater coronary and myocardial perfusion, and lower thrombus burden at initial angiogram in patients with STEMI undergoing primary percutaneous coronary intervention.

Prehospital Tirofiban Increases the Rate of Disrupted Myocardial Infarction in Patients with ST-Segment Elevation Myocardial Infarction: Insights From the On-TIME 2 Trial.

BACKGROUND: In patients with ST-segment elevation myocardial infarction (STEMI), prehospital tirofiban significantly improved myocardial reperfusion. However, its impact on the rate of disrupted myocardial infarction (MI), particularly in the context of high-sensitive cardiac troponin (hs-cTn) assays, is still unclear. METHODS: The On-TIME 2 (The Ongoing Tirofiban In Myocardial infarction Evaluation 2) trial randomly assigned STEMI patients to prehospital tirofiban or placebo before transportation to a percutaneous coronary intervention (PCI) centre. In this post hoc analysis, we evaluated STEMI patients that underwent primary PCI and had measured hs-cTn levels. Troponin T levels were collected at 18-24 h and 72-96 h after PCI. Disrupted MI was defined as peak hs-cTn T levels ≤10 times the upper limit of normal (≤140 ng/L). RESULTS: Out of 786 STEMI patients, 47 (6%) had a disrupted MI. Disrupted MI occurred in 31 of 386 patients (8.0%) in the tirofiban arm and in 16 of 400 patients (4.0%) in the placebo arm (p=0.026). After multivariate adjustment, prehospital tirofiban remained independently associated with disrupted MI (OR 2.03; 95% CI 1.10 to 3.87; P= 0.027). None of the patients with disrupted MI died during the one-year follow-up, compared to a mortality rate of 2.6% among those without disrupted MI. CONCLUSION: Among STEMI patients undergoing primary PCI, the use of prehospital tirofiban was independently associated with a higher rate of disrupted MI. These results, highlighting a potential benefit, underscore the need for future research focusing on innovative pretreatment approaches which may increase the rate of disrupted MI.

Temporary omission of oral anticoagulation in atrial fibrillation patients undergoing percutaneous coronary intervention: rationale and design of the WOEST-3 randomised trial.

The optimal antithrombotic management of atrial fibrillation (AF) patients who require oral anticoagulation (OAC) undergoing percutaneous coronary intervention (PCI) remains unclear. Current guidelines recommend dual antithrombotic therapy (DAT; OAC plus P2Y12 inhibitor - preferably clopidogrel) after a short course of triple antithrombotic therapy (TAT; DAT plus aspirin). Although DAT reduces bleeding risk compared to TAT, this is counterbalanced by an increase in ischaemic events. Aspirin provides early ischaemic benefit, but TAT is associated with an increased haemorrhagic burden; therefore, we propose a 30-day dual antiplatelet therapy (DAPT; aspirin plus P2Y12 inhibitor) strategy post-PCI, temporarily omitting OAC. The study aims to compare bleeding and ischaemic risk between a 30-day DAPT strategy following PCI and a guideline-directed therapy in AF patients requiring OAC. WOEST-3 (ClinicalTrials.gov: NCT04436978) is an investigator-initiated, international, open-label, randomised controlled trial (RCT). AF patients requiring OAC who have undergone successful PCI will be randomised within 72 hours after PCI to guideline-directed therapy (edoxaban plus P2Y12 inhibitor plus limited duration of aspirin) or a 30-day DAPT strategy (P2Y12 inhibitor plus aspirin, immediately discontinuing OAC) followed by DAT (edoxaban plus P2Y12 inhibitor). With a sample size of 2,000 patients, this trial is powered to assess both superiority for major or clinically relevant non-major bleeding and non-inferiority for a composite of all-cause death, myocardial infarction, stroke, systemic embolism or stent thrombosis. In summary, the WOEST-3 trial is the first RCT temporarily omitting OAC in AF patients, comparing a 30-day DAPT strategy with guideline-directed therapy post-PCI to reduce bleeding events without hampering efficacy.

Parenteral Antiplatelet Drugs in ST-Elevation Myocardial Infarction: Current Status and Future Directions.

Oral inhibitors of the platelet P2Y12 receptor are indispensable in the treatment of ST-elevation myocardial infarction (STEMI), improving outcomes and even reducing mortality in some studies. However, these drugs are limited by delayed absorption and suboptimal platelet inhibition at the time of primary percutaneous coronary intervention. Despite efforts to achieve faster and more sustained platelet inhibition, strategies such as prehospital administration, higher loading doses, and crushed formulations have not led to improved coronary reperfusion. Parenteral glycoprotein IIb/IIIa inhibitors act sooner and are more potent than oral P2Y12 inhibitors, but their use has been limited by the increased risk of major bleeding and thrombocytopenia. Hence, there is a clinical need to refine drugs that deliver rapid, effective, yet safe platelet inhibition in the setting of STEMI. Novel parenteral antiplatelet drugs, such as cangrelor, selatogrel, and zalunfiban, have been recently developed to achieve rapid, potent antiplatelet effects while preserving hemostasis. We provide a description of currently available parenteral antiplatelet agents and of those in clinical development for prehospital administration in STEMI patients.

Critical Analysis of Thrombocytopenia Associated With Glycoprotein IIb/IIIa Inhibitors and Potential Role of Zalunfiban, a Novel Small Molecule Glycoprotein Inhibitor, in Understanding the Mechanism(s).

Thrombocytopenia is a rare but serious complication of the intravenous glycoprotein IIb/IIIa (GPIIb/IIIa; integrin αIIbß3) receptor inhibitors (GPIs), abciximab, eptifibatide, and tirofiban. The thrombocytopenia ranges from mild (50 000-100 000 platelets/µL), to severe (20 000 to <50 000/µL), to profound (<20 000/µL). Profound thrombocytopenia appears to occur in <1% of patients receiving their first course of therapy. Thrombocytopenia can be either acute (<24 hours) or delayed (up to ~14 days). Both hemorrhagic and thrombotic complications have been reported in association with thrombocytopenia. Diagnosis requires exclusion of pseudothrombocytopenia and heparin-induced thrombocytopenia. Therapy based on the severity of thrombocytopenia and symptoms may include drug withdrawals and treatment with steroids, intravenous IgG, and platelet transfusions. Abciximab-associated thrombocytopenia is most common and due to either preformed antibodies or antibodies induced in response to abciximab (delayed). Readministration of abciximab is associated with increased risk of thrombocytopenia. Evidence also supports an immune basis for thrombocytopenia associated with the 2 small molecule GPIs. The latter bind αIIbß3 like the natural ligands and thus induce the receptor to undergo major conformational changes that potentially create neoepitopes. Thrombocytopenia associated with these drugs is also immune-mediated, with antibodies recognizing the αIIbß3 receptor only in the presence of the drug. It is unclear whether the antibody binding depends on the conformational change and whether the drug contributes directly to the epitope. Zalunfiban, a second-generation subcutaneous small molecule GPI, does not induce the conformational changes; therefore, data from studies of zalunfiban will provide information on the contribution of the conformational changes to the development of GPI-associated thrombocytopenia.

Dual versus triple antithrombotic therapy after percutaneous coronary intervention: the prospective multicentre WOEST 2 Study.

BACKGROUND: For patients on oral anticoagulants (OAC) undergoing percutaneous coronary intervention (PCI), European guidelines have recently changed their recommendations to dual antithrombotic therapy (DAT; P2Y12 inhibitor and OAC) without aspirin. AIMS: The prospective WOEST 2 registry was designed to obtain contemporary real-world data on antithrombotic regimens and related outcomes after PCI in patients with an indication for OAC. METHODS: In this analysis, we compare DAT (P2Y12 inhibitor and OAC) to triple antithrombotic therapy (TAT; aspirin, P2Y12 inhibitor, and OAC) on thrombotic and bleeding outcomes after one year. Clinically relevant bleeding was defined as Bleeding Academic Research Consortium classification (BARC) grade 2, 3, or 5; major bleeding as BARC grade 3 or 5. Major adverse cardiac and cerebrovascular events (MACCE) was defined as a composite of all-cause mortality, myocardial infarction, stent thrombosis, ischaemic stroke, and transient ischaemic attack. RESULTS: A total of 1,075 patients were included between 2014 and 2021. Patients used OAC for atrial fibrillation (93.6%) or mechanical heart valve prosthesis (4.7%). Non-vitamin K oral anticoagulants (NOAC) were prescribed in 53.1% and vitamin K antagonists in 46.9% of patients. At discharge, 60.9% received DAT, and 39.1% TAT. DAT was associated with less clinically relevant and similar major bleeding (16.8% vs 23.4%; p<0.01 and 7.6% vs 7.7%, not significant), compared to TAT. The difference in MACCE between the two groups was not statistically significant (12.4% vs 9.7%; p=0.17). Multivariable adjustment and propensity score matching confirmed these results. CONCLUSIONS: Dual antithrombotic therapy is associated with a substantially lower risk of clinically relevant bleeding without a statistically significant penalty in ischaemic events.