Exploring optimal administration timing of pegylated recombinant human granulocyte colony-stimulating factor for chemotherapy-induced neutropenia in early breast cancer treated with pharmorubicin and endoxan: a prospective randomized controlled clinical trial.

Background: Pegylated recombinant human granulocyte colony-stimulating factor (PEG-rhG-CSF) is a treatment for preventing febrile neutropenia (FN) in patients with early breast cancer. However, the optimal injection timing of PEG-rhG-CSF after chemotherapy is obscure. The trial was designed to explore the best administration timing of PEG-rhG-CSF when breast cancer patients could benefit most.

Methods: Patients with early breast cancer were randomly assigned to receive a preventive injection on the 7th or 3rd day following chemotherapy. The experimental group (n = 80) received PEG-rhG-CSF treatment on day 7 after chemotherapy, whereas the control group (n = 80) received it on day 3. The occurrence of grades 3-4 neutropenia and FN in the first cycle was the primary endpoint. The secondary endpoint was the frequency of PEG-rhG-CSF dose reduction.

Results: In comparison to the control group, the experimental group exhibited higher white blood cell count (WBC) and absolute neutrophil count (ANC) on the 9th and 13th days following chemotherapy (P < 0.05). Additionally, the incidence of grade 3-4 neutropenia was significantly lower in the experimental group (P = 0.038). Furthermore, a greater proportion of patients in the experimental group met the criteria for reducing the PEG-rhG-CSF dose compared to the control group (69.74% vs. 35.06%, P < 0.001).

Conclusions: In comparison with PEG-rhG-CSF injection on day 3 after chemotherapy, the incidence of grade 3-4 myelosuppression is lower, and the safety is more manageable after the injection on day 7. This approach potentially allows for a wider adoption of PEG-rhG-CSF dose reduction, leading to a consequential decrease in overall medical costs for patients.

Trial Registration: Clinical Trials: NCT04477616. Registered July 16, 2020.