1032 Background: Limited data exist on the efficacy and safety of biological agents in elderly patients with aBC. This is essentially due to the lack of studies specifically targeting the older population and to strict inclusion criteria in clinical trials. B significantly improved the efficacy of 1st-line taxane therapy in two large, randomized phase III trials, E2100 and AVADO. Methods: In study MO19391, 1st-line B 10mg/kg q2w or 15mg/kg q3w + CT (primarily but not exclusively taxane monotherapy) was investigated in a broader, large aBC patient population, with the aim of understanding safety and efficacy in patients seen in routine clinical practice, including elderly patients. Results: A total of 2,027 patients were enrolled. Median age was 54 years (range 21–93); 359 patients (17.7%) were aged ≥65 years and 169 (8.3%) were ≥70 years. Baseline characteristics and safety and efficacy results according to age are shown below (Table). Conclusions: Treatment with B is feasible in elderly patients. Hypertension was the only grade 3 B-related side effect reported more frequently in the older than in the younger cohort. Efficacy was similar in the two subgroups. These results suggest that the combination of B with 1st-line CT shows a similar therapeutic index regardless of age. Data on compliance according to the different CT regimens, the impact of comorbidities on safety, and analyses in the subgroup of patients ≥70 years will be presented. [Table: see text] [Table: see text]