The effectiveness of oxaliplatin in children has not been established. Oxaliplatin has been tested in 2 Phase 1 and 2 Phase 2 trials in 235 patients ages 7 months to 22 years with solid tumors (see below) and no significant activity observed.
In a Phase 1/2 study, oxaliplatin was administered as a 2-hour intravenous infusion on Days 1, 8 and 15 every 4 weeks (1 cycle), for a maximum of 6 cycles, to 43 patients with refractory or relapsed malignant solid tumors, mainly neuroblastoma and osteosarcoma. Twenty eight pediatric patients in the Phase 1 study received oxaliplatin at 6 dose levels starting at 40 mg/m2 with escalation to 110 mg/m2. The dose limiting toxicity (DLT) was sensory neuropathy at the 110 mg/m2 dose. Fifteen patients received oxaliplatin at a dose of 90 mg/m2 intravenous in the Phase 2 portion of the study. At this dose, paresthesia (60%, G3/4: 7%), fever (40%, G3/4: 7%) and thrombocytopenia (40%, G3/4: 27%) were the main adverse reactions. No responses were observed.
In a second Phase 1 study, oxaliplatin was administered to 26 pediatric patients as a 2-hour intravenous infusion on day 1 every 3 weeks (1 cycle) at 5 dose levels starting at 100 mg/m2 with escalation to 160 mg/m2, for a maximum of 6 cycles. In a separate cohort, oxaliplatin 85 mg/m2 was administered on day 1 every 2 weeks, for a maximum of 9 doses. Patients had metastatic or unresectable solid tumors mainly neuroblastoma and ganglioneuroblastoma. No responses were observed. The DLT was sensory neuropathy at the 160 mg/m2 dose. Based on these studies, oxaliplatin 130 mg/m2 as a 2-hour intravenous infusion on day 1 every 3 weeks (1 cycle) was used in subsequent Phase II studies. A dose of 85 mg/m2 on day 1 every 2 weeks was also found to be tolerable.
In one Phase 2 study, 43 pediatric patients with recurrent or refractory embryonal CNS tumors received oxaliplatin 130 mg/m2 every 3 weeks for a maximum of 12 months in absence of progressive disease or unacceptable toxicity. In patients < 10 kg the oxaliplatin dose used was 4.3 mg/kg. The most common adverse reactions reported were leukopenia (67%, G3/4: 12%), anemia (65%, G3/4: 5%), thrombocytopenia (65%, G3/4: 26%), vomiting (65%, G3/4: 7%), neutropenia (58%, G3/4: 16%) and sensory neuropathy (40%, G3/4: 5%). One partial response was observed.
In a second Phase 2 study, 123 pediatric patients with recurrent solid tumors, including neuroblastoma, osteosarcoma, Ewing sarcoma or peripheral PNET, ependymoma, rhabdomyosarcoma, hepatoblastoma, high grade astrocytoma, Brain stem glioma, low grade astrocytoma, malignant germ cell tumor and other tumors of interest received oxaliplatin 130 mg/m2 every 3 weeks for a maximum of 12 months or 17 cycles. In patients < 12 months old the oxaliplatin dose used was 4.3 mg/kg. The most common adverse reactions reported were sensory neuropathy (52%, G3/4: 12%), thrombocytopenia (37%, G3/4: 17%), anemia (37%, G3/4: 9%), vomiting (26%, G3/4:4%), ALT increased (24%, G3/4: 6%), AST increased (24%, G3/4: 2%), and nausea (23%, G3/4: 3%). Two partial responses were observed.
The pharmacokinetic parameters of ultrafiltrable platinum have been evaluated in 105 pediatric patients during the first cycle. The mean clearance in pediatric patients estimated by the population pharmacokinetic analysis was 4.7 L/h. The inter-patient variability of platinum clearance in pediatric cancer patients was 41%. Mean platinum pharmacokinetic parameters in ultrafiltrate were Cmax of 0.75 ± 0.24 mcg/mL, AUC0–48 of 7.52 ± 5.07 mcg∙h/mL and AUCinf of 8.83 ± 1.57 mcg∙h/mL at 85 mg/m2 of oxaliplatin and Cmax of 1.10 ± 0.43 mcg/mL, AUC0–48 of 9.74 ± 2.52 mcg∙h/mL and AUCinf of 17.3 ± 5.34 mcg∙h/mL at 130 mg/m2 of oxaliplatin.