6-beta-hydroxycortisol and Lung-Neoplasms

Docetaxel is metabolized by cytochrome P450 (CYP3A4) enzyme, and the area under the concentration-time curve (AUC) is correlated with neutropenia. We developed a novel method for estimating the interpatient variability of CYP3A4 activity by the urinary metabolite of exogenous cortisol (6-beta-hydroxycortisol [6-beta-OHF]). This study was designed to assess whether the application of our method to individualized dosing could decrease pharmacokinetic (PK) and pharmacodynamic (PD) variability compared with body-surface area (BSA) -based dosing.. Fifty-nine patients with advanced non-small-cell lung cancer were randomly assigned to either the BSA-based arm or individualized arm. In the BSA-based arm, 60 mg/m(2) of docetaxel was administered. In the individualized arm, individualized doses of docetaxel were calculated from the estimated clearance (estimated clearance = 31.177 + [7.655 x 10(-4) x total 6-beta-OHF] - [4.02 x alpha-1 acid glycoprotein] - [0.172 x AST] - [0.125 x age]) and the target AUC of 2.66 mg/L . h.. In the individualized arm, individualized doses of docetaxel ranged from 37.4 to 76.4 mg/m(2) (mean, 58.1 mg/m(2)). The mean AUC and standard deviation (SD) were 2.71 (range, 2.02 to 3.40 mg/L . h) and 0.40 mg/L . h in the BSA-based arm, and 2.64 (range, 2.15 to 3.07 mg/L . h) and 0.22 mg/L . h in the individualized arm, respectively. The SD of the AUC was significantly smaller in the individualized arm than in the BSA-based arm (P < .01). The percentage decrease in absolute neutrophil count (ANC) averaged 87.1% (range, 59.0 to 97.7%; SD, 8.7) in the BSA-based arm, and 87.4% (range, 78.0 to 97.2%; SD, 6.1) in the individualized arm, suggesting that the interpatient variability in percent decrease in ANC was slightly smaller in the individualized arm.. The individualized dosing method based on the total amount of urinary 6-beta-OHF after cortisol administration can decrease PK variability of docetaxel.

Topics: Aged; Antineoplastic Agents, Phytogenic; Area Under Curve; Body Surface Area; Carcinoma, Non-Small-Cell Lung; Cytochrome P-450 CYP3A; Cytochrome P-450 Enzyme System; Docetaxel; Drug Administration Schedule; Female; Humans; Hydrocortisone; Lung Neoplasms; Male; Middle Aged; Taxoids

An association between skin toxicity and outcome has been reported for NSCLC patients treated with erlotinib. Several explanations have been suggested, including pharmacokinetic and pharmacogenomic variability. The purposes of this study were to characterize erlotinib pharmacokinetic and to correlate drug serum and urine levels to toxicity and outcomes in advanced NSCLC patients.. Patients with stage IV NSCLC consecutively treated with erlotinib in second- or third-line were enrolled. Biological samples (blood, urine and tumor specimens) were collected. Erlotinib levels in serum and urine samples of all patients after 7 (T1) and 30 (T2) days of treatment were quantified by LC-MS/MS analysis, along with urinary 6β-hydroxycortisol/cortisol ratio, as marker of metabolic phenotype of the CYP3A4/5 enzyme.. 56 patients were recruited and for 46 all samples were available. At T1 erlotinib levels were 3.90 [2.13] μmol/l and 0.37 [2.90]μmol/mol creat in serum and urinary samples, respectively; at T2 drug concentrations were significantly lower (2.02 [4.05] μmol/l and 0.23 [4.47] μmol/mol creat, respectively). Patients with grade 3 skin toxicity showed serum T1 drug levels significantly higher than those with grade 0-2 (6.84 [2.28] vs. 3.08 [1.97] μmol/l, respectively, p=0.004) and had longer progression-free and overall survival. An inverse correlation between erlotinib serum levels and urinary 6β-hydroxycortisol/cortisol ratio was observed in patients with grade 3 skin toxicity.. These findings suggest that the pharmacokinetics and metabolism of erlotinib are related to skin toxicity and may support further studies where erlotinib dosing is tailored according to pharmacokinetic parameters.

Topics: Aged; Carcinogenesis; Carcinoma, Non-Small-Cell Lung; Erlotinib Hydrochloride; Female; Humans; Hydrocortisone; Lung Neoplasms; Male; Middle Aged; Neoplasm Staging; Quinazolines; Skin; Survival Analysis; Treatment Outcome