ABSTRACT
PURPOSE: We investigated nilotinib exposure in pediatric patients with chronic myeloid leukemia (CML) or Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL) resistant to, relapsed on, refractory to, or intolerant of previous treatment. PATIENTS AND METHODS: Fifteen patients (aged 1-<18 years) with CML resistant to or intolerant of imatinib and/or dasatinib (n = 11) or Ph+ ALL relapsed on or refractory to standard therapy (n = 4) enrolled in this phase I study. Nilotinib (230 mg/m2 twice daily; equivalent to the adult 400-mg twice-daily dose) was administered orally in 12 or 24 cycles of 28 days. The primary objective was to characterize the pharmacokinetics of nilotinib in pediatric patients. RESULTS: The area under the concentration-time curve at steady state was slightly lower in pediatric patients versus adults (14,751.4 vs. 17,102.9 ng/h/mL); the geometric mean ratio (GMR; pediatric:adult) was 0.86 [90% confidence interval (CI), 0.70-1.06]. Body surface area-adjusted systemic clearance was slightly higher in pediatric versus adult patients (GMR, 1.30; 90% CI, 1.04-1.62). Nilotinib was generally well tolerated. The most common adverse events were headache, vomiting, increased blood bilirubin, and rash. Three patients with CML achieved major molecular response, and three with Ph+ ALL achieved complete remission. CONCLUSIONS: Nilotinib 230 mg/m2 twice daily in pediatric patients provided a pharmacokinetics and safety profile comparable with the adult reference dose; clinical activity was demonstrated in both CML and Ph+ ALL. This dose is recommended for further evaluation in pediatric patients. The safety profile was consistent with that in adults.
Subject(s)
Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/metabolism , Precursor Cell Lymphoblastic Leukemia-Lymphoma/drug therapy , Precursor Cell Lymphoblastic Leukemia-Lymphoma/metabolism , Pyrimidines/pharmacokinetics , Pyrimidines/therapeutic use , Adolescent , Child , Child, Preschool , Drug Administration Schedule , Drug Resistance, Neoplasm , Female , Fusion Proteins, bcr-abl/genetics , Fusion Proteins, bcr-abl/metabolism , Humans , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/pathology , Male , Precursor Cell Lymphoblastic Leukemia-Lymphoma/genetics , Precursor Cell Lymphoblastic Leukemia-Lymphoma/pathology , Protein Kinase Inhibitors/pharmacokinetics , Protein Kinase Inhibitors/therapeutic use , Tissue DistributionABSTRACT
PURPOSE: Activating KIT mutations are part of the pathogenesis of systemic mastocytosis (SM). Nilotinib is a tyrosine kinase inhibitor that potently inhibits activated forms of KIT. This phase 2, open-label, single-arm study (CAMN107A2101; www.clinicaltrials.gov NCT00109707) evaluated nilotinib in patients with SM. METHODS: Patients with SM [aggressive SM (ASM), indolent SM, or other] received nilotinib 400 mg twice daily. C-findings were collected retrospectively to assess response using criteria proposed after trial initiation. Response was evaluated using improvements in laboratory findings (for all patients) and ASM response criteria (for the ASM subgroup). RESULTS: In 61 patients enrolled, the median nilotinib exposure was 232 days (range 3-1274 days) with a median follow-up of 34.7 months. In patients with ASM (n = 37), the overall response rate was 21.6 %. In the eight responders, all of whom had a KIT D816V mutation at any time, mast cell infiltration and tryptase level decreased by 70 % and 29.8 %, respectively; absolute neutrophil count increased by 94.7 %. Laboratory parameters also improved in the non-ASM subgroups. Overall survival at 24 months was 81.2 % (95 % CI 70.6-91.8 %) with median survival not yet reached. New or worsening grade 3/4 hematologic adverse events (AEs) included thrombocytopenia (10.3 %), anemia (10.0 %), and neutropenia (6.9 %). The most common grade 3/4 nonhematologic drug-related AEs were diarrhea (6.6 %) and headache (4.9 %). Eleven patients (9 with ASM, 2 with MCL) died, 10 due to progressive disease; 7 deaths occurred ≥28 days after treatment discontinuation. CONCLUSIONS: Nilotinib 400 mg twice daily was effective in some patients with SM, including patients with mutated KIT D816V.
