1574P - Efficacy and safety of RGB-02, a proposed biosimilar pegfilgrastim to prevent chemotherapy-induced neutropenia: Results of a randomized, double-blind, phase III clinical study vs. reference pegfilgrastim in patients with breast cancer receiving docetaxel/doxorubicin

Abstract

Background: Treatment with recombinant human granulocyte-colony stimulating factor (G-CSF) is accepted standard for prevention of chemotherapy-induced neutropenia. RGB-02, a pegylated G-CSF (pegfilgrastim) developed by Gedeon Richter is a proposed biosimilar to the reference pegfilgrastim product Neulasta®. Here we are presenting the results of a randomized, comparative, double-blind, multicenter study to evaluate efficacy and safety of RGB-02 in breast cancer patients receiving cytotoxic regimen (EudraCT nr: 2013-003166-14). Methods: 239 women presenting with breast cancer were randomized to RGB-02 (n = 121) and to the reference pegfilgrastim, Neulasta® (n = 118). All patients received up to 6 cycles of docetaxel/doxorubicin and a once-per-cycle injection of a fixed 6 mg dose of pegfilgrastim. Primary endpoint was the duration of severe neutropenia (ANC < 0.5 x109/L) in Cycle 1 (2-sided CI interval 95%). Secondary endpoints included incidence and duration of severe neutropenia, incidence of febrile neutropenia, time to ANC recovery, depth of ANC nadir, and safety outcomes. Results: The mean duration of severe neutropenia in Cycle 1 was 1.7 (RGB-02) and 1.6 days (reference), with a difference (LS Mean) of 0.1 days (95% CI -0.2, 0.4). Therapeutic equivalence could be established as the CI for the difference in LS Mean lay entirely within the pre-defined range of ± 1 day. The incidence of severe neutropenia decreased from cycle 1 to 2 in both groups with no statistical significant differences, for RGB-02 from 84.6% (99 patients) to 54.1% (60 patients) and from 77.0% (87 patients) to 43.7% (45 patients) in the comparator group. Both groups were similar regarding mean time to ANC recovery with 3.4 ± 1.84 days (RGB-02) and 3.7 ± 1.88 days (reference) during Cycle 1. Safety profiles were comparable between groups. Conclusions: Therapeutic equivalence and similar safety profiles between RGB-02 and Neulasta® as once-per-cycle administration could be demonstrated. RGB-02 can provide a biosimilar alternative for the prevention of neutropenia. Clinical trial identification: EudraCT nr: 2013-003166-14 Legal entity responsible for the study: Gedeon Richter Plc. Funding: Gedeon Richter Plc. Disclosure: K. Horvat-Karajz, A. Illes: Employee of Gedeon Richter Plc. All other authors have declared no conflicts of interest.