BACKGROUND: Iron supplementation improves the erythropoiesis-stimulating agents' (ESAs) response in chemotherapy-related anemia. The primary aim of our study is to assess the efficacy of sucrosomial iron, a new oral iron formulation, in cancer patients with chemotherapy-induced anemia treated with ESAs. The secondary objectives included the efficacy into two subgroups of patients (iron replete and functional iron deficiency) between the two study arms, safety and the effect on transfusion need. METHODS: In this randomized, multicentre, open-label, phase III clinical trial, 60 cancer patients were enrolled. Each patient was randomly assigned (1:1) to receive 12 weeks of oral sucrosomial iron at the dose of 30 mg daily in combination with ESAs or no supplementation to ESA treatment. The endpoint considered for efficacy was the proportion of patients achieving complete hematological response at 12 weeks (increase in Hb > 2 g/dL from baseline, without RBC transfusions in the previous 28 days or achieving Hb ≥ 12 g/dL). RESULTS: There was a statistically significant association between oral sucrosomial iron supplementation in combination with ESAs and the achievement of a complete hematological response. This response was achieved within 12 weeks by 31% of patients in the control group and by 52% of patients supplemented with oral sucrosomial iron. A trend of greater response in sucrosomial iron arm was found in both subgroups. No difference was observed about safety and transfusion need. CONCLUSIONS: Sucrosomial iron is well tolerated and its combination with ESAs improves the hematological response in cancer patients with chemotherapy-related anemia. TRIAL REGISTRATION NUMBER AND DATE OF REGISTRATION: This study has been reviewed by the Institutional Ethics Committee of the IRCCS Policlinico San Matteo Foundation, Pavia, Italy (28/04/2015; prot. N. 20,150,002,059), and by the Institutional Ethics Committee of the other Italian oncological centers involved in this study.