Combined Antioxidant Therapy for Acute Myocardial Infarction (CAT-AMI)

Acute myocardial infarction (AMI) remains as a leading cause of morbidity and mortality worldwide. In patients with ST-segment elevation myocardial infarction (STEMI), early reperfusion with primary percutaneous coronary intervention (PCI) is the standard treatment to limit myocardial injury. However, reperfusion induces additional damage, referred to as ischemia-reperfusion injury (IRI), which has been estimated to account for up to 50% of final infarct size. Oxidative stress is a key mechanism in IRI and contributes to lipid peroxidation, inflammation, and regulated cell death pathways. Prior pharmacologic approaches directed at single components of this process have shown limited and inconsistent clinical benefit, supporting evaluation of multitarget strategies.

This study is a phase II, randomized, double-blind, placebo-controlled, parallel-group superiority trial designed to evaluate the efficacy and safety of a combined antioxidant therapy (CAT) in patients with acute STEMI undergoing primary PCI. CAT consists of ascorbate, N-acetylcysteine, and deferoxamine. These agents were selected to target complementary mechanisms relevant to IRI: reactive oxygen species scavenging, glutathione replenishment, redox modulation and inflammatory response, and iron chelation with inhibition of iron-dependent lipid peroxidation. The study will randomly assign participants in a 1:1 ratio to receive CAT or matching placebo in addition to guideline-based STEMI treatment.

The intervention will be initiated before reperfusion and maintained during primary PCI in order to ensure drug exposure during the early reperfusion phase. Both groups will receive standard-of-care treatment for STEMI, including primary PCI and guideline-directed medical therapy.

The trial is designed as a signal-seeking phase II study using infarct size as the primary efficacy endpoint. Infarct size measured by cardiac magnetic resonance (CMR) is a mechanistically relevant endpoint in cardioprotection trials and has established prognostic value. In this study, CMR will be performed during the index hospitalization to quantify infarct size as a percentage of left ventricular mass. Additional imaging variables, myocardial injury biomarkers, oxidative stress and inflammatory biomarkers, pharmacokinetic measurements, short-term clinical outcomes, and safety data will be collected to support interpretation of the primary analysis. These assessments include left ventricular systolic function, hs-cTnI, CK, CK-MB, plasma concentrations of the study drugs, and 30-day follow-up for clinical events and adverse events.

The planned sample size is 46 participants. The study is powered to detect a large between-group difference in infarct size, consistent with its exploratory phase II design. Accordingly, the trial is intended to determine whether CAT demonstrates a sufficiently large efficacy signal, together with an acceptable safety profile, to support further evaluation in a larger trial.

Safety monitoring will include systematic collection of adverse events and serious adverse events during hospitalization and through day 30. Events will be recorded using Medical Dictionary for Regulatory Activities (MedDRA) terminology.

This trial will provide phase II data on the efficacy, safety, pharmacokinetics, and mechanistic effects of a multitarget antioxidant strategy administered during primary PCI in patients with STEMI.