Effect of ZaStaprazan on Platelet Reactivity of Clopidogrel After PercuTaneous CoronAry InteRvention (EZ-STAR)

Effect of ZaStaprazan on Platelet Reactivity of Clopidogrel After PercuTaneous CoronAry InteRvention: A Randomized Double-Blind Pilot Study (EZ-STAR)

The purpose of this study is to evaluate the clinical utility of zastaprazan compared to proton pump inhibitors (PPIs) in patients receiving dual antiplatelet therapy (DAPT) including clopidogrel after percutaneous coronary intervention (PCI), by comparing their effects on platelet reactivity.

Study Overview

• Status: Recruiting
• Conditions: Chronic Coronary Syndrome
• Intervention / Treatment: Drug: Rabeprazole; Drug: Zastaprazan

Detailed Description

This study aims to evaluate the impact of zastaprazan on platelet reactivity when co-administered with clopidogrel and to identify differences in potential drug-drug interactions compared to conventional Proton Pump Inhibitors (PPIs). Through this, we intend to propose an optimal combination strategy that simultaneously addresses antiplatelet efficacy and gastrointestinal protection.

Notably, as rabeprazole is known to have a lower degree of CYP2C19 inhibition among PPIs, this study will specifically compare zastaprazan with rabeprazole to evaluate and confirm the comparative effects on platelet reactivity.

• Study Type: Interventional
• Enrollment (Estimated): 100
• Phase: Phase 4

Contacts and Locations

• Study Contact: Name: Yongcheol Kim, MD, PhD; Phone Number: +82-031-5189-8967; Email: yongcheol@yuhs.ac

Study Locations

• South Korea
  • Gyeonggi-do
    • Yongin-si, Gyeonggi-do, South Korea, 16995
      • Recruiting
      • Yongin Severance Hospital, Yonsei University
      • Contact: Yongcheol Kim, MD; Phone Number: +823151898967; Email: yongcheol@yuhs.ac

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Age 19 years or older at the time of providing informed consent.
2. Patients with Chronic Coronary Syndrome (CCS) who have undergone Percutaneous Coronary Intervention (PCI) and agreed to participate in the study.
3. Patients who are required to maintain dual antiplatelet therapy (DAPT) including clopidogrel for at least 6 months after PCI.
4. Patients who have voluntarily provided written informed consent to participate in this clinical study.

Exclusion Criteria:

1. History of hypersensitivity to P-CABs, PPIs, benzimidazoles, aspirin, clopidogrel, or any of the excipients in the study drugs.
2. History of or planned surgery that may affect gastric acid secretion, such as upper gastrointestinal resection, acid suppression surgery, or gastric mucosal resection. (However, patients who have undergone simple perforation repair of the stomach or duodenum, appendectomy, cholecystectomy, hysterectomy, or endoscopic/laparoscopic resection of benign tumors are eligible).
3. Diagnosis of Zollinger-Ellison syndrome or inflammatory diseases (e.g., pancreatitis, or inflammatory bowel diseases such as Crohn's disease or ulcerative colitis).
4. Currently receiving HIV protease inhibitors (atazanavir, nelfinavir) or rilpivirine-containing products.
5. Abnormal blood chemistry values within 4 weeks prior to screening: AST, ALT, ALP, or total bilirubin > 3 times the upper limit of normal (ULN). Estimated Glomerular Filtration Rate (eGFR) < 30 mL/min/1.73m², calculated using the IDMS-traceable MDRD equation.
6. Recent Medication Use: Use of medications expected to affect the study results, such as P2Y12 inhibitors (other than the prescribed clopidogrel), within 2 weeks prior to baseline.
7. Pregnant or lactating women, or women with a positive pregnancy test.
8. Patients with hereditary problems such as galactose intolerance, Lapp lactase deficiency, or glucose-galactose malabsorption.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: zastaprazan 20mg; Participants receive zastaprazan 20mg and Placebo matching Pariet 10mg tablet 10mg.	Drug: Rabeprazole; Participants will receive Rabeprazole [10 mg] orally once daily for [6month] in addition to standard dual antiplatelet therapy (DAPT) including clopidogrel (75 mg/day).
Experimental: Pariet 10mg; Participants receive Pariet 10mg and Placebo matching zastaprazan 20mtablet 10mg.	Drug: Zastaprazan; Participants will receive Zastaprazan [20 mg] orally once daily for [6 month] in addition to standard dual antiplatelet therapy (DAPT) including clopidogrel (75 mg/day).

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Assessment of platelet reactivity using P2Y12 Reaction Units (PRU) by the VerifyNow assay at 1 month	Assessment of platelet reactivity using P2Y12 Reaction Units (PRU) by the VerifyNow assay at 1 month	1 month

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Platelet Reactivity	Change in Platelet Reactivity	1 month, 3 months, and 6 months
Proportion of Participants Achieving Platelet Reactivity Within the Therapeutic Range	Change in Platelet Reactivity	1 month
Incidence of Major Adverse Cardiovascular Events (MACE)	Composite of cardiovascular death, myocardial infarction, or stroke.	6 month
Incidence of Individual Components of Major Adverse Cardiovascular Events (MACE)	Cardiovascular death, myocardial infarction, and stroke evaluated separately.	6 month
Incidence of Coronary Revascularization	Incidence of Coronary Revascularization	6 month
All-cause Mortality	All-cause Mortality	6 month
Incidence of Upper Gastrointestinal (GI) Bleeding	Incidence of Upper Gastrointestinal (GI) Bleeding	6 month
Incidence of Bleeding Events According to BARC Criteria (Types 2, 3, or 5)	Incidence of Bleeding Events According to BARC Criteria (Types 2, 3, or 5)	6 month
Incidence of Adverse Drug Reactions (ADRs)	Incidence of Adverse Drug Reactions (ADRs)	6 month

Collaborators and Investigators

• Sponsor: Yonsei University
• Collaborators: Jeil Pharmaceutical Co., Ltd.

Study record dates

Study Major Dates

• Study Start (Actual): April 2, 2026
• Primary Completion (Estimated): July 12, 2028
• Study Completion (Estimated): July 12, 2028

Study Registration Dates

• First Submitted: March 4, 2026
• First Submitted That Met QC Criteria: March 11, 2026
• First Posted (Actual): March 13, 2026

Study Record Updates

• Last Update Posted (Actual): April 24, 2026
• Last Update Submitted That Met QC Criteria: April 22, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: Chronic Coronary Syndrome; zastaprazan
• Additional Relevant MeSH Terms: 2-Pyridinylmethylsulfinylbenzimidazoles; Sulfoxides; Sulfur Compounds; Organic Chemicals; Pyridines; Heterocyclic Compounds, 1-Ring; Heterocyclic Compounds; Benzimidazoles; Heterocyclic Compounds, 2-Ring; Heterocyclic Compounds, Fused-Ring; Rabeprazole
• Other Study ID Numbers: 9-2025-0234

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No