Abstract P3-15-01: Primary G-CSF Prophylaxis during the First Two Cycles Only or Throughout All Chemotherapy Cycles in Breast Cancer Patients at Risk of Febrile Neutropenia: Final Results from a Phase III Trial of the Dutch Breast Cancer Trialists Group (BOOG)

Background: In patients at risk of febrile neutropenia (FN), the highest incidence of FN is seen during the first chemotherapy cycles. This observation questions the effectiveness of continued G-CSF prophylaxis during later chemotherapy cycles. Methods: We conducted a multicenter phase III study in breast cancer. Patients were randomized to primary G-CSF prophylaxis during the first two chemotherapy cycles only (experimental arm) or to primary G-CSF prophylaxis throughout all chemotherapy cycles (standard arm). Patients were eligible if treated with 3-weekly chemotherapy, being at risk of FN according to criteria of international guidelines. This was an equivalence study, aimed to include 230 patients, with FN as primary endpoint. Results: An independent Data Safety Monitoring Board recommended premature closure of the study because of an unacceptable increase in FN rate in the experimental arm. In total, 85 patients enrolled the experimental arm and 84 patients the standard arm till 15 th December 2009. Baseline characteristics were well belanced: age ≥65years in 93% versus 95%, ECOG PS of zero in 82% versus 88%, treated with docetaxel containing chemotherapy in (neo)-adjuvant setting in 97% versus 100%, respectively. At least one episode of FN was seen in 27 (32%) patients of the experimental arm compared with 4 (5%) patients in the standard arm (P Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P3-15-01.