BACKGROUND: Preliminary data suggest that pegfilgrastim given on day 4 (P4) might be superior to pegfilgrastim on day 2 (P2) in reducing grade 4 leucopenia. METHODS: Patients with node-positive primary breast cancer receiving epirubicin-paclitaxel-cyclophosphamide chemotherapy were randomized to receive P2 versus P4. Primary endpoint was leucopenia grade 4, assuming a risk reduction of 50% with P4 from 50% in P2 to 25% with P4. RESULTS: Three-hundred fifty-one patients were randomized to P2 (n = 174) versus P4 (n = 177). The rate of leucopenia (grade 4) was 47.1% with P2 and 42.0% with P4 (p = 0.387), neutropenia (grade 3 + 4) was 47.9% versus 40.8% (p = 0.337), FN was 4.7% versus 8.0% (p = 0.271), and infections was 29.9% versus 25.4% (p = 0.404), respectively. CONCLUSION: This study failed to demonstrate that pegfilgrastim on day 4 was more efficacious than on day 2 with respect to grade 4 leucopenia (the primary endpoint), febrile neutropenia, or infections.
