An open-label, randomized study comparing lipegfilgrastim with filgrastim in pediatric patients receiving chemotherapy for Ewing sarcoma or rhabdomyosarcoma

This study compared efficacy and safety of lipegfilgrastim with filgrastim in pediatric patients. Children and adolescents receiving chemotherapy (4 cycles) for Ewing sarcoma or rhabdomyosarcoma were randomized 1:1 to lipegfilgrastim (100 µg/kg) once per cycle or filgrastim (5 µg/kg), once daily for ≥ 5 days for up to 14 days or until absolute neutrophil count (ANC) recovery. In 39 evaluable patients, no meaningful difference was observed between lipegfilgrastim and filgrastim treatment groups in duration of severe neutropenia (DSN; mean [standard deviation]) in cycle 1 (2.7 [2.25] vs. 2.5 [2.09] days); least squares mean treatment difference (lipegfilgrastim minus filgrastim) 1.0 day (95% CI: -0.21,2.26) or cycles 2-4, duration of very severe neutropenia in cycles 1-4, incidence of severe neutropenia (85% vs. 84%) or very severe neutropenia (70% vs. 68%). The incidence of febrile neutropenia was numerically lower with lipegfilgrastim (35%) vs. filgrastim (42%). Mean area under the curve of ANC until day 15 in cycle 1 was numerically higher with lipegfilgrastim vs. filgrastim (105 × 10⁹/L*days vs. 84 × 10⁹/L*days). There were no meaningful differences between treatment groups, in cycles 1-4, in mean ANC nadir values, or time to ANC nadir or ANC recovery. Mean administration of lipegfilgrastim was less than filgrastim (4 vs. 31.7 times). No unexpected safety signals were observed. Lipegfilgrastim demonstrated comparable efficacy and tolerability to filgrastim in reducing duration and incidence of neutropenia. A reduced dosing frequency of once per cycle could be particularly beneficial for children, enhancing convenience and improving adherence.