Efficacy and safety of balugrastim compared with pegfilgrastim in patients with breast cancer receiving chemotherapy

Abstract

Background: Recombinant granulocyte colony-stimulating factors (G-CSFs) reduce the incidence and duration of chemotherapy-induced neutropenia and febrile neutropenia when given as adjunct therapy to patients receiving myelosuppressive chemotherapy. Balugrastim is a long-acting G-CSF composed of a genetic fusion between recombinant human serum albumin and G-CSF. We compared the efficacy and safety of balugrastim and pegfilgrastim, a long-acting pegylated recombinant G-CSF, in patients with breast cancer who were scheduled to receive chemotherapy.

Patients and methods: In this double-blind randomized phase III trial, patients with ≥ 1.5 × 10(9) neutrophils/L were randomly assigned to subcutaneous injections of balugrastim 40 mg (n = 153) or pegfilgrastim 6 mg (n = 151). The primary efficacy end point was the duration of severe neutropenia (DSN) (days with an absolute neutrophil count [ANC] < 0.5 × 10(9) cells/L) during cycle 1. Efficacy analyses were performed in the per-protocol (PP) population. In a separate open-label single-arm study, newly recruited patients (n = 77) received balugrastim 40 mg and were included in the safety analysis.

Results: The mean DSN in cycle 1 was 1.1 days in the balugrastim group and 1.0 days in the pegfilgrastim group (95% confidence interval [CI], -0.13-0.37). Two and 4 patients, respectively, had febrile neutropenia during cycle 1. Twenty percent of patients in the balugrastim group and 19% in the pegfilgrastim group had adverse events (AEs) considered to be related to study medication; 3.9% and 4.7% of patients, respectively, experienced serious AEs.

Conclusions: This study demonstrates the comparable safety and efficacy profile of balugrastim and pegfilgrastim and the noninferiority of balugrastim for reduction in DSN. There were no unexpected safety events.

Trial registration: ClinicalTrials.gov NCT01126190.

Keywords: Balugrastim; Breast cancer; Neutropenia; Pegfilgrastim; Recombinant granulocyte colony-stimulating factor.