A Study of Acute Myocardial Infarction Using FDY-5301

The purpose of this study is to evaluate the safety and effectiveness of an experimental drug called FDY-5301 as a possible treatment to reduce the size of the injury to the heart caused by the heart attack. An experimental drug is one that is being tested and is not approved by the United States Food and Drug Administration (FDA).

A heart attack occurs when a heart (coronary) artery supplying blood to the heart muscle becomes blocked and the heart muscle is injured. You will be having a cardiac catheterization procedure to clear the blockage in your coronary artery that caused your heart attack. This procedure works well but may not completely prevent some injury to the heart muscle which occurs when the blood supply is initially restored to the heart. This is known as "reperfusion injury".

FDY-5301 is a single intravenous injection. About 80 subjects are expected to participate in this study at about 20 research sites in the United States and Europe. Each subject's participation is expected to last about 6 months after receiving the study drug.

Subjects who meet all inclusion criteria will be randomly assigned to one of 4 study groups. Three groups will receive FDY-5301 (low, intermediate, or high dose) and 1 group will receive a placebo.The study drug (FDY-5301 or placebo) will be given through a vein (intravenously) during the catheterization procedure. This is a double-blind study so neither the patient nor study personnel will know whether the dose is active drug or placebo until the end of the study.

Inclusion criteria

• 18-80 year old male subjects
• 18 to 80 year old female subjects who are not of child-bearing potential.
• Accepted for Primary PCI with diagnosis of first STEMI, based on clinical and ECG criteria (ST-elevation at the J-point in two contiguous leads with the cut-off points: ≥0.2 millivolt (mV) in men or ≥0.15 mV in women in leads V2-V3 and/or ≥0.1 mV in other leads), within 12 hours of symptom onset.

Written informed consent prior to study participation (either by the subject or a legally authorized representative of the subject)

Exclusion criteria

• Previous myocardial infarction
• Left bundle branch block (LBBB)
• Previous coronary artery bypass graft surgery (CABG)
• Major hemodynamic instability or uncontrolled ventricular arrhythmias
• Known contraindication to CMR
• Patients with known thyroid disease
• Subjects with past or current renal impairment requiring dialysis
• Pregnant or females of child bearing potential
• Body weight > 120 kg or Body Mass Index (BMI) > 35 kg/m2
• Use of investigational drugs or devices within 30 days prior to enrollment into the study.
• Life expectancy of less than 1 year due to non-cardiac pathology
• Any clinically significant abnormality identified at the time of screening that in the judgment of the Investigator or any sub-Investigator would preclude safe completion of the study