Dosing celecoxib in pediatric patients with juvenile rheumatoid arthritis.

The objective was to derive dosing recommendations for the use of celecoxib in patients with juvenile rheumatoid arthritis (JRA) using pharmacokinetic (PK) and exposure-response data. PK and efficacy data from a randomized, double-blind, 12-week study of celecoxib dosed at 3 and 6 mg/kg twice a day (bid) as an investigational suspension formulation in 152 JRA patients aged 2 to 17 years, PK data from 36 adult RA patients, and relative bioavailability data in healthy adults comparing suspension or capsule sprinkles with the commercial capsule were analyzed. Typical oral clearance (L/h) values were 40% and 24% lower in patients weighing 10 and 25 kg, respectively, compared with a 70-kg patient. Longitudinal, logistic pharmacodynamic models incorporating linear effects of dose/area under the plasma concentration-time curve (AUC) over 0 to 12 hours (AUC(0-12)) suggested that the percentage of responders increased with celecoxib exposure. Systemic exposures (AUC) were similar for the suspension, capsule sprinkles, and intact capsule. Administration of a 50-mg bid capsule (or sprinkles) for patients weighing 10 to 25 kg and 100 mg bid for patients >25 kg was predicted to yield similar exposures and response rates as those observed in the JRA trial. Doses and dosage forms not studied in the JRA trial were approved based on the results of this analysis.