Balugrastim(Teva Biopharmaceuticals USA, Inc.)

Balugrastim is a once-per-cycle, fixed-dose recombinant protein comprising human serum albumin and granulocyte colony-stimulating factor under development for prevention of severe neutropenia in cancer patients receiving myelosuppressive chemotherapy. This phase II, multicenter, active-controlled, dose-finding pilot study evaluated balugrastim safety and efficacy versus pegfilgrastim in breast cancer patients scheduled to receive myelosuppressive chemotherapy and investigated two doses with similar efficacy to pegfilgrastim for a subsequent phase III study. Patients received four cycles of doxorubicin/docetaxel chemotherapy and with each successive cycle were randomized sequentially to escalating doses of balugrastim [30 (n = 11), 40 (n = 21), or 50 mg (n = 20)] or a fixed dose of pegfilgrastim [6 mg (n = 26)] post-chemotherapy. Balugrastim doses were escalated as planned. The incidence of adverse events was similar among the balugrastim groups and between all balugrastim doses and pegfilgrastim. The most frequently reported adverse events were neutropenia, alopecia, and nausea. During cycle 1, severe neutropenia (absolute neutrophil count of <0.5 × 10(9)/L) occurred in 40, 67, and 50 % and febrile neutropenia occurred in 20.0, 9.5, and 10.0 % of patients receiving balugrastim 30, 40, and 50 mg, respectively; in patients receiving pegfilgrastim, 48 % experienced severe neutropenia and 8 % experienced febrile neutropenia. Duration of severe neutropenia (DSN) for each treatment group was 0.9, 1.6, 1.1, and 0.9 days, respectively. In the remaining three chemotherapy cycles, DSN was ≤1 day across all treatment groups. Balugrastim 50 mg was comparable to pegfilgrastim in terms of safety and overall efficacy in breast cancer patients receiving myelosuppressive chemotherapy.

To evaluate safety of balugrastim, a recombinant human serum albumin and granulocyte colony-stimulating factor (G-CSF), administered over a range of therapeutic doses in women with breast cancer receiving doxorubicin plus docetaxel chemotherapy.

The phase I, sequential dose-escalation first segment compared subcutaneous balugrastim 50, 150, 300, and 450 µg/kg during chemotherapy cycles 0-2. The randomized (2:2:1), open-label, phase IIa second segment compared balugrastim 300 or 450 µg/kg with pegfilgrastim 6 mg during chemotherapy cycles 1 and 2.

In the phase I segment, balugrastim was escalated to 450 µg/kg in 13 patients without dose-limiting toxicity. Three (9.7 %) of the 31 adverse events (AEs) reported in nine patients were grade 3 (agranulocytosis, vomiting, hypertension); none was grade 4. In the open-label phase IIa segment (N = 51), the majority of the 64 AEs reported in 31 (75.6 %) balugrastim-treated patients were grade 1 (59.4 %), with 39.1 % grade 2, 1.6 % grade 3 (one AE of vomiting), and none grade 4. Of the 16 AEs reported in seven (70.0 %) pegfilgrastim-treated patients, 87.5 % were grade 1, 6.3 % were grade 2, 6.3 % were grade 3 (one AE of thrombocytopenia), and none were grade 4. Overall, there were six bone pain AEs reported, one in the balugrastim 300 µg/kg group and five in the balugrastim 450 µg/kg group. No AEs in either study necessitated treatment interruption/discontinuation. The incidence and duration of grade 3-4 neutropenia were similar between balugrastim- and pegfilgrastim-treated patients.

Balugrastim was well tolerated in this small population of breast cancer patients.