A phase I study of different doses and frequencies of pegylated recombinant human granulocyte-colony stimulating factor(PEG rhG-CSF) in patients with standard-dose chemotherapy-induced neutropenia

Objective: The recommended dose of prophylactic pegylated recombinant human granulocyte-colony stimulating factor(PEG rhG-CSF) is 100 μg/kg once per cycle for patients receiving intense-dose chemotherapy.However, few data are available on the proper dose for patients receiving less-intense chemotherapy. The aim of this phase I study is to explore the proper dose and administration schedule of PEG rhG-CSF for patients receiving standard-dose chemotherapy.Methods:Eligible patients received 3-cycle chemotherapy every 3 weeks.No PEG rhG-CSF was given in the first cycle.Patients experienced grade 3 or 4 neutropenia would then enter the cycle 2 and 3.In cycle 2,patients received a single subcutaneous injection of prophylactic PEG rhG-CSF on d 3,and received half-dose subcutaneous injection in cycle 3 on d 3 and d 5,respectively.Escalating doses(30,60,100 and 200μg/kg)of PEG rhG-CSF were investigated.Results:A total of 26 patients were enrolled and received chemotherapy,in which 24 and 18 patients entered cycle 2 and cycle 3 treatment,respectively.In cycle 2,the incidence of grade 3 or 4 neutropenia for patients receiving single-dose PEG rhG-CSF of 30,60,100 and 200 μg/kg was 66.67%,33.33%,22.22% and 0,respectively,with a median duration less than 1(0–2)d.No grade 3 or higher neutropenia was noted in cycle 3 in all dose cohorts.Conclusions:The pharmacokinetic and pharmacodynamic profiles of PEG rhG-CSF used in cancer patients were similar to those reported,as well as the safety.Double half dose administration model showed better efficacy result than a single dose model in terms of grade 3 neutropenia and above.The single dose of 60 μg/kg,100 μg/kg and double half dose of 30 μg/kg were recommended to the phase Ⅱ study,hoping to find a preferable method for neutropenia treatment.