The combined effect of subcutaneous granulocyte- colony stimulating factor and myocardial contrast echocardiography with intravenous infusion of sulfur hexafluoride on post-infarction left ventricular function, the RIGENERA 2.0 trial: study protocol for a randomized controlled trial.

Background: Several clinical trials and recent meta-analyses have demonstrated that administration of recombinant human granulocyte-colony stimulating factor (G-CSF) is safe and, only in patients with large acute myocardial infarction (AMI), is associated with an improvement in left ventricular ejection fraction. Moreover, the mobilization and engraftment of the bone marrow-derived cells may differ significantly among patients, interfering with the restoration of left ventricular function after treatment. Therefore, the clinical potential application of the G-CSF has not yet been fully elucidated.

Methods/design: The RIGENERA 2.0 trial is a multicenter, phase II, placebo-controlled, randomized, open-label, with blinded evaluation of endpoints (PROBE) trial in which 120 patients with an acute ST-elevation myocardial infarction (STEMI) undergoing successful revascularization but with residual myocardial dysfunction will be enrolled. In cases where there is a left ventricular ejection fraction (LVEF) ≤ 45% the patient will be electronically randomized (1:1 ratio) to receive either subcutaneous recombinant human G-CSF (group 1) or placebo (group 2) both added on top of optimal standard of care. Both groups will undergo myocardial contrast echocardiography with intravenous infusion of sulfur hexafluoride (MCE) whilst undergoing the echocardiogram. The primary efficacy endpoint is the evaluation of the LVEF at 6 months after AMI assessed by cardiac magnetic resonance. Secondary efficacy endpoints are the evaluation of LVEF at 6 months after AMI assessed by echocardiography, left ventricular end-diastolic volume (LVEDV) and left ventricular end-systolic volume (LVESV) assessed by cardiac magnetic resonance and echocardiography at 6 months, together with the incidence of major adverse clinical events (MACE) defined as death, myocardial infarction, sustained cardiac arrhythmias, cardiogenic shock, stroke and re-hospitalization due to heart failure at 1 year.

Discussion: The RIGENERA 2.0 trial will test whether G-CSF administration and MCE, through the enhancement of the bone marrow-derived cells homing in the myocardium, determines an improvement in regional and global contractile function, myocardial perfusion and infarct extension in patients with large AMI. The results of the present study are expected to envision routine clinical use of this safe, affordable and reproducible approach in patients with successful revascularization after AMI.

Trial Registration: ClinicalTrials.gov: NCT02502747 (29 June 2015); EudraCT: 2015-002189-21 (10 July 2015).