Infarct size is a major determinant of prognosis after myocardial infarction (MI). It has been reported that Cyclosporine A (CsA) administered immediately prior to percutaneous coronary intervention (PCI) significantly could reduce reperfusion injury and consequently infarct size in ST elevation MI (STEMI) patients.

CYCLE trial is a multicenter, controlled, randomized open label study, with blind assessment of endpoint measures. The objective is to determine whether a single i.v. dose of CsA within 6 hour onset of symptoms of STEMI in 444 patients, improves outcomes after successful primary PCI, by reducing myocardial injury associated to reperfusion.

The possibility of optimizing the results of an early and effective reopening of the occluded artery by reducing/avoiding the impact of the so-called reperfusion injury has been for many years one of the most elusive objectives of pharmacological research, with evolving hypothesis and targets.

A recently published trial has provided support to a line of investigation focused on the role of mitochondrial dysfunction, the so-called permeability transition, as cause of irreversible myocardial injury associated to reperfusion. In fact, a single dose of the widely used immunosuppressant agent, CsA, a potent inhibitor of mitochondrial permeability transition pore opening, was reported to limit ischemia-reperfusion injury in 50 patients with anterior MI who underwent primary PCI.

Since infarct size and left ventricular function are the main determinants of long-term morbidity and mortality, a single measure to limit infarct size is of potential clinical benefit. Therefore the results of the previously mentioned trial should be replicated in a larger sample size, before going on to a trial with clinical endpoints.

- Sample size

Assuming an incidence of the primary endpoint of 55% in the control group, we calculated that 444 patients (222 patients per group) will be required for the study to have 80% power to detect a 25% relative improvement (resulting in an endpoint frequency of 68.7% in the CsA group) with a 5% drop-out rate and a two-sided alpha level of 5%. The size of the trial will allow to investigate treatment benefit for the secondary endpoint hsTnT: assuming a concentration of 2.7 ng/mL on day 4 (common SD=2.1) in the control group, the study will have a 90% power to show a 25% reduction with CsA at a two-sided alpha level of 5%.

- Safety

Adverse events with intravenous CsA (i.e. anaphylactoid reactions/anaphylactic shock, acute renal failure, or hypertensive crisis) are reported to be very rare. In this trial, patients will receive only one iv dose of CsA, therefore we expect a low probability of adverse effects related to repeated administrations, i.e. acute renal failure or hypertensive crisis. Nonetheless a close monitoring of the safety of the single dose of CsA is foreseen with monthly examination of data of safety by the Steering Committee.

Inclusion Criteria:

• Male and female patients with large STEMI not older than 6 hours, defined as
• angina pectoris or equivalent symptoms of more than 20 minutes duration within last 6 hours, and
• ST elevation in at least 3 leads in anterior MI and/or a deviation in at least 4 leads in inferior MI,
• TIMI flow 0 or 1 in identified culprit artery
• Intended acute primary PCI
• Age ≥ 18 years
• Ability to understand the nature, scope, and possible consequences of the study participation/legal capacity
• Written informed consent

Exclusion Criteria:

• Left bundle branch block
• TIMI flow > 1 in the identified culprit artery
• Treatment with CsA within last 10 days
• Contraindication to CsA or history of allergic reaction to CsA
• Coronary anatomy not suitable for PCI
• Thrombolytic therapy within 24 h. before randomization
• Previous MI
• Previous CABG
• Severe renal or hepatic insufficiency
• Malignant tumor, not curatively treated
• Women with childbearing potential, esp. pregnant or nursing women
• Participation in another clinical or device trial within the previous 30 days