Vincristine dosing, drug exposure and therapeutic drug monitoring in neonate and infant cancer patients

Background: The anticancer drug vincristine is associated with potentially dose-limiting side-effects, including neurotoxicity and myelosuppression. However, there currently exists a lack of published clinical pharmacology data relating to its use in neonate and infant patients. We report a study investigating vincristine dosing and drug exposure, alongside the feasibility and impact of a therapeutic drug monitoring treatment approach, in this chal-lenging patient population. Patients and methods: Vincristine pharmacokinetic data from a total of 57 childhood cancer patients, including 26 neonates and infants, were used to characterise a population pharmaco-kinetic model. Vincristine was administered at doses of 0.02-0.05 mg/kg or 0.75-1.5 mg/m(2) in neonates and infants aged < 1 year or <= 12 kg and doses of 1.5 mg/m(2) in older children. Results: A two-compartment model provided the best fit for the population analysis. There was no significant difference in vincristine clearance normalised for body surface area between neonates/infants and older children. Lower doses administered to neonates and infants re-sulted in significantly lower drug exposures (area under the curve [AUC]), compared with old -er children (p =0.047). Vincristine doses of < 0.05 mg/kg in neonates and infants resulted in significantly lower AUC values than observed in those receiving doses of >= 0.05 mg/kg (p <= 0.0001). Therapeutic drug monitoring was shown to be feasible, effective and well toler-ated in neonates and infants experiencing suboptimal drug exposures. Conclusion:Doses of < 0.05 mg/kg should not be used in neonate and infant patients becauseof a high risk of patients experiencing potentially suboptimal drug exposures. Therapeuticdrug monitoring approaches in neonates and infants are supported by the data generated, witha proposed target therapeutic window of 50e100mg/l*h. (C) 2021 The Authors. Published by Elsevier Ltd

Automated summary

This study investigated vincristine dosing, drug exposure, and the feasibility of therapeutic drug monitoring in neonate and infant patients. The results suggest that doses of <0.05mg/kg should not be used in this population due to a risk of suboptimal drug exposures, and therapeutic drug monitoring approaches are effective.