Effects of Renal Function on Pharmacokinetics of Recombinant Human Granulocyte Colony-Stimulating Factor in Lung Cancer Patients

Animal studies suggest that the kidney is involved in the elimination of recombinant human granulocyte colony-stimulating factor (rhG-CSF), which is used for patients with neutropenia during cancer chemotherapy. Since anticancer drugs induce nephrotoxicity, it is important to clarify the role of the kidney in the pharmacokinetics of rhG-CSF in cancer patients. Our study was designed to evaluate the relationship between the pharmacokinetics of rhG-CSF and renal function in lung cancer patients compared to the absolute neutrophil count (ANC). The pharmacokinetic studies were conducted with 25 lung cancer patients. Following chemotherapy using platinum-based compounds, a bolus 5 microg of rhG-CSF/kg of body weight was intravenously injected from the first day of leukopenia or neutropenia. Pharmacokinetic parameters were estimated by fitting the concentration in serum-time data to a two-compartment model according to the population pharmacokinetics and the Bayesian method. Creatinine clearance (CL(CR)) was predicted by the Cockcroft-Gault formula. rhG-CSF clearance (CL(G-CSF)) correlated significantly with the ANC (r = 0.613; P < 0.001) and CL(CR) (r = 0.632; P < 0.001). Multiple linear regression analysis showed that the combination of the ANC and CL(CR) accounted for 57.4% of the variation of CL(G-CSF). In patients with an ANC of <1,000/microl, CL(CR) accounted for 72.9% of the variation of CL(G-CSF) (P < 0.001). Our findings suggest that renal function and neutrophil counts correlate with CL(G-CSF) and that the role of renal function in eliminating rhG-CSF is important in lung cancer patients with neutropenia.