Comparative pharmacokinetics, safety, and tolerability of two sources of ch14.18 in pediatric patients with high-risk neuroblastoma following myeloablative therapy.

PURPOSE: Dinutuximab (Unituxin™; ch14.18), a monoclonal antibody against disialoganglioside, improved survival as part of post-consolidation therapy for high-risk neuroblastoma. United Therapeutics Corporation (UTC) assumed ch14.18 production from the National Cancer Institute (NCI); this study evaluates pharmacokinetic comparability, safety, and tolerability of UTC and NCI products. METHODS: In this randomized, two-sequence crossover study, 28 patients aged ≤8 years with high-risk neuroblastoma received equivalent ch14.18-UTC or ch14.18-NCI doses. Despite comparable protein content, nominal doses differed: 17.5 mg/m(2)/day (ch14.18-UTC) and 25 mg/m(2)/day (ch14.18-NCI). Patients received one product during therapy cycles 1 and 2, the other during cycles 3-5. Ch14.18 pharmacokinetic profile characterization used population modeling (NONMEM(®) version 7.2). A two-compartment model with first-order distribution and elimination processes described pharmacokinetic data. Estimated product parameters were normalized to UTC nominal dose. For pharmacokinetic comparability, the final model was used to estimate exposure ratios (UTC/NCI) and associated 90 % confidence intervals (CIs) for area under the curve from time zero to infinity (AUCinf) and maximum concentration (C max). All comparisons were based on a standardized single-dose regimen (17.5 mg/m(2) over 10 h). RESULTS: Final-model pharmacokinetic parameters were similar to previously published ch14.18-NCI parameters and comparable for UTC and NCI products. Products' systemic exposures were comparable, with 90 % CIs around ratios for AUCinf (0.96; 90 % CI 0.88-1.04) and C max (1.04; 90 % CI 0.98-1.11) within standard bioequivalence bounds (90 % CI 0.80-1.25). Products' adverse events were similar and consistent with those previously reported. CONCLUSIONS: Equivalent actual ch14.18-UTC and ch14.18-NCI doses produced comparable exposures, with no notable safety or tolerability differences.

Pharmacokinetics of the chimeric anti-GD2 antibody, ch14.18, in children with high-risk neuroblastoma.

PURPOSE: Ch14.18 improves survival in children with high-risk neuroblastoma but is associated with substantial toxicity. Ch14.18 pharmacokinetics were previously reported to be highly variable and characterized by a higher clearance in children than in adults, and a large volume of distribution. Identifying factors responsible for its variability could lead to alternative dosing strategies that reduce toxicity. METHODS: Plasma sampling was performed prior to, during, and for 25 days after four daily 10-h infusions of 25 mg/m(2) of ch14.18 administered with sargramostim. Ch14.18 concentrations were quantified with an electrochemiluminescence immunoassay, and pharmacokinetic parameters were derived using non-compartmental methods and from fitting a two-compartment model. Human anti-chimeric antibody (HACA) was measured before each course. RESULTS: Fourteen subjects (median age, 4.3 years) were enrolled; seven had sampling on two courses to assess intra-subject variability. Mean peak ch14.18 plasma concentration was 11 µg/mL, and disappearance was biexponential with half-life of 7 days. Mean trough (day 28) concentration was 0.2 µg/mL. Mean AUC0-∞ was 1,380 µg h/mL and was less variable than previously reported (CV 29 %). Intra-patient variability was also minimal, but one subject who developed HACA had a 41 % decrease in AUC 0-tlast from courses 1 to 3. Clearance (2 L/day m(2)) was fourfold higher in children than in adults and appeared to be age dependent. Steady state volume of distribution was 0.4 L/kg. Two-compartment model parameters were used to simulate alternative dosing schedules. CONCLUSIONS: Ch14.18 disposition in children is less variable than previously reported. Clearance is age dependent and more rapid in younger children.