OBJECTIVES: TO compare efficacy and safety of lenograstim and filgrastim in stem cell mobilization in healthy donors (allogenic transplantation) and in oncological patients (autologous transplantation). METHODS: Comparison was based on randomized controlled trials (RCTs) identified by means of systematic review, carried out according to the Cochrane Collaboration guidelines. The most important medical databases were searched (EMBASE, MEDLINE, CENTRAL). Two reviewers independently selected trials, assessed their quality and extracted data. Meta-analysis of head-to-head trials was performed to compare lenograstim and filgrastim in stem cell mobilization in healthy donors and oncological patients. RESULTS: The results of 4 RCTs in healthy donors and 3 RCTs in oncological patients were included in the analysis. For healthy donors mobilization with lenograstim resulted in higher number of CD34+ cells harvested than mobilization with filgrastim (WMD=0.66 x 106 per kg of body weight [0.05; 1.26]). No differences between lenograstim and filgrastim were found in the number of donors requiring second apheresis (RR=0.91 [0.62; 1.35]). Adverse events rates were similar in both arms. Most common adverse events including bone pain and arthralgia. For oncological patients no differences in the number of patients that gained target CD34+ cells (>2x106) were found (RR=0.72 [0.33; 1.55]). Results for hematological recovery are inconsistent. No significant differences in the incidence of neutropenia were noted (RR=0.72 [0.50; 1.03]) whereas platelet transfusions were more frequent in filgrastim treated patients than in lenograstim group (RR=0.16 [0.04; 0.67]). The length of hospital stay after transplantation was similar in both groups. No significant differences regarding safety outcomes were reported. CONCLUSIONS: In healthy donors lenograstim is more potent than filgrastim in stem cell mobilization into peripheral blood and no differences in safety profiles between two drugs were noted. In oncological patients both drugs has similar impact on stem cell mobilization while lenograstim dicreases the risk of platelet transfusion. Acknowledgements: This analysis was supported by Sanofi-Aventis.