Abstract
Proteins secreted into urine following tubular injury are being increasingly used as biomarkers of clinical and subclinical nephrotoxicity. In the present study, we sought to characterize the time-dependent urinary excretion of three promising biomarkers, kidney injury molecule-1 (KIM-1), calbindin, and trefoil factor 3 (TFF3), during two different chemotherapy cycles in 27 patients with solid tumors prescribed the anticancer drug cisplatin (≥25 mg/m(2)). Urinary biomarkers were evaluated at Days 3 and 10 during an initial and a subsequent cycle of cisplatin chemotherapy. Longitudinal analyses compared the mean difference estimations for biomarker concentrations during and across the initial and subsequent cycles of cisplatin treatment. Traditional biomarkers including serum creatinine, estimated glomerular filtration rate, and blood urea nitrogen were unchanged during and across both cycles of cisplatin therapy. In response to the initial cycle, urinary KIM-1 concentrations increased from baseline and remained elevated through a subsequent cycle of cisplatin chemotherapy. By comparison, urinary levels of calbindin were elevated 10 days after the initial cisplatin treatment, but largely unchanged by cisplatin exposure in a subsequent cycle. Early elevations in urinary TFF3 at 3 days after cisplatin administration were observed consistently in both the initial and subsequent cycle of cisplatin treatment. In conclusion, the longitudinal assessment of biomarker performance in the same cohort of oncology patients reveals different patterns of urinary excretion between initial and subsequent cycles of cisplatin-containing chemotherapy. These data add novel cycle-dependent insight to the growing literature addressing the ability of urinary biomarkers to detect subclinical renal injury in patients receiving cisplatin.