A universal formula based on cystatin C to perform individual dosing of carboplatin in normal weight, underweight, and obese patients

2527 Background: It has recently been shown that it is possible to improve the prediction of carboplatin clearance by adding plasma cystatin C level (cysC), an endogenous marker of glomerular filtration rate, to the other patient characteristics routinely used for carboplatin individual dosing, namely serum creatinine (Scr), body weight (BW), age, and sex. This multi-center pharmacokinetic study was performed to evaluate prospectively the benefit of using cysC for carboplatin individual dosing. Methods: The 357 patients included in the study were receiving carboplatin as part of established protocols. A population pharmacokinetic analysis was performed using the NONMEM program. Seven covariates were studied: Scr, cysC, age, sex, BW, ideal body weight, and lean body mass. Results: The best covariate equation was: carboplatin clearance (mL/min) = 105. (Scr/75)-0.433. (cysC/1.00)-0.290 . (BW/65)+0.547 . (age/56)-0.351 . 0.855sex, with Scr in μmol/L, cysC in mg/L, BW in kg, age in years, and sex = 0 for male....