An Open-Label Multicenter Safety, Tolerability, and Efficacy Study of Recombinant Granulocyte Colony-Stimulating Factor in the Prevention of Neutropenic Complications in Breast Cancer Patients

The primary objective of this open-label, two chemotherapy arm, phase 4 study was to evaluate the safety and efficacy of newly developed recombinant granulocyte colony-stimulating factor (rG-CSF) used to prevent neutropenia-related complications in patients with metastatic breast cancer treated with docetaxel (75 mg/m2) and doxorubicin (50 mg/m2) or docetaxel (100 mg/m2) alone. Material and Methods. A total of 50 patients who were treated with a maximum of 6 cycles of either docetaxel-doxorubicin (36 patients) or docetaxel alone (14 patients) every 21 days were recruited from 3 centers in Lithuania. All the patients received study medication rG-CSF at a dosage of 5 μg/kg per day (Sicor Biotech UAB, Teva Group) from day 2 of each cycle and continued for minimum 5 days or until absolute neutrophil count reached ≥1.5×109/L. Results. A total of 611 adverse events were reported. Most of them were related to myelotoxic chemotherapy. Two patients withdrew due to adverse events (neuropathy and bone pain). One patient died possibly because of pulmonary thromboembolism. The most frequently reported adverse events related to study drug in the docetaxel-doxorubicin and docetaxel groups were leukocytosis (22% and 21%, respectively), bone pain (19% and 21%, respectively), and headache (8% and 14%, respectively). The incidence of grade 4 neutropenia in both the groups was 47% and 29%, respectively, in all cycles and 42% and 21%, respectively, in cycle 1. The incidence of febrile neutropenia was 8% in cycle 1 and 14% across all cycles. The mean duration of febrile neutropenia was 2.1 days (SD, 1.9) in cycle 1 and 2.14 days (SD 2.0) across all cycles in both the treatment groups. Conclusion. This study provide data that the study drug rG-CSF has the expected safety and could be an efficacious medication to decrease the risk of febrile neutropenia and related complications of myelosuppressive chemotherapy in patients with metastatic breast cancer.