Cisplatin pharmacokinetics and pharmacodynamics in patients with squamous-cell carcinoma of the head/neck or esophagus.

The pharmacokinetics of total platinum (Pt) in plasma and cisplatin (CDDP)-DNA adducts in different cell types were described in ten patients with squamous-cell carcinoma of the head/neck or esophagus after their first cycle of chemotherapy containing a CDDP dose of 100 mg/m2. Nephrotoxicity was studied in terms of urinary excretion of marker proteins (protein HC, IgG, and albumin). Pharmacodynamic relationships between pharmacokinetic parameters and toxicity were investigated. A population-based model with limited sampling was found feasible for producing pharmacokinetic information, in accordance with literature data. The kinetics of two normal cell types with different turnover (lymphocytes and buccal cells) appeared to have different kinetic profiles of CDDP-DNA adducts. Analysis of urinary excretion of marker proteins (protein HC, albumin, and IgG) showed that the nephrotoxicity was displayed first as tubular damage and later as impaired glomerular barrier function. There were indications that tubular nephrotoxicity may be predicted by pharmacokinetic parameters of plasma Pt. We found older patients to have a lower Pt clearance and more extensive early tubular damage. There was no correlation between CDDP-DNA adducts in normal cells and nephrotoxicity. Larger studies are warranted to define the pharmacokinetic window of CDDP. Limited sampling for analysis of CDDP pharmacokinetics may then be a possible avenue for individualizing the dose and, thus, improving the clinical use of the drug.