Clinical outcome after stem cell mobilization with granulocyte-colony-stimulating factor after acute ST-elevation myocardial infarction: 5-year results of the STEMMI trial

BACKGROUND: Granulocyte-colony-stimulating factor (G-CSF) has been investigated in trials aiming to promote recovery of myocardial function after myocardial infarction. Long-term safety-data have never been reported. A few studies indicated an increased risk of in-stent re-stenosis. We aimed to investigate clinical events 5 years after inclusion into a randomized trial of G-CSF versus placebo. METHODS: Seventy-eight patients were randomized, from 2003-2005, to G-CSF or placebo after myocardial infarction. Four patients withdrew consent prior to study treatment and were excluded leaving 36 and 38 in the placebo- and G-CSF groups. Information about all hospital admittances of included patients until 2010 was extracted from a national register. The only censoring event was immigration. The events were combined into four prespecified endpoints: Time to (1) first hospital admittance (all cause), (2) first cardiovascular-related hospital admittance, (3) first major cardiovascular event, and (4) death. RESULTS: One patient (1%) was lost to follow-up. Four patients (4%) died in the follow-up period, three in the G-CSF group and one in the placebo group (p = 0.4). Hazard ratio for all cause hospital admittance was 0.7 (95% CI 0.38-1.29). The incidence of both new myocardial infarction (p = 1.0) and revascularization procedures (p = 0.4) were similar in the two groups. Survival analyses showed no differences in the occurrence of any of the four prespecified composite endpoints between the two groups (p = 0.6; 0.5; 0.8; 0.3). CONCLUSIONS: We found no indication of increased risk of adverse events up to 5 years after G-CSF treatment. These results support the continued investigation of G-CSF for cardiac therapy.