In animal models, G-CSF based progenitor cell mobilization combined with a DPP4 inhibitor leads to increased homing of bone marrow derived progenitor cells to the injured myocardium via the SDF1/CXCR4 axis resulting in improved ejection fraction and survival after acute myocardial infarction (AMI).After successful revascularization in AMI, 174 patients were randomized 1:1 in a multi-centre, prospective, placebo-controlled, parallel group, double blind, phase III efficacy and safety trial to treatment with G-CSF and Sitagliptin (GS) or placebo. Diabetic and non-diabetic patients were included in our trial. The primary efficacy endpoint hierarchically combined global left and right ventricular ejection fraction changes from baseline to 6months of follow-up (ΔLVEF, ΔRVEF), as determined by cardiac MRI.At follow-up ΔLVEF as well as ΔRVEF did not differ between the GS and placebo group. Patients in the placebo group had a similar risk for a major adverse cardiac event within 12months of follow-up as compared to patients under GS.Progenitor cell therapy comprising the use of G-CSF and Sitagliptin after successfully revascularized acute myocardial infarction fails to show a beneficial effect on cardiac function and clinical events after 12months. (EudraCT: 2007–003,941-34; ClinicalTrials.gov: NCT00650143, funding: Heinz-Nixdorf foundation).