Reply to G.J. Veal et al

Abstract

I heartily agree with the insightful comments of Veal and Boddy regarding the need for appropriate planned population pharmacokinetic studies, especially in infants, to provide better data on which to base chemotherapy dosing. They also suggest real-time therapeutic drug monitoring to inform subsequent day carboplatin dose adjustments, a practice routinely used in the United Kingdom. However, from a practical standpoint, the chemotherapy regimen with the largest published experience in the United States uses a single dose of carboplatin in addition to vincristine and etoposide (CEV). Importantly, in a Children’s Hospital of Philadelphia retrospective analysis of 116 patients treated with CEV, no ototoxicity developed in patients with normal baseline hearing. CEV is also the regimen used by the Children’s Oncology Group in the largest prospective international trial of adjuvant chemotherapy for retinoblastoma after enucleation. Although therapeutic drug monitoring clearly has a role in multiday carboplatin regimens, especially in the setting of high-dose therapy, it is not a strategy that would be feasible with the most commonly used American systemic chemotherapeutic regimen for retinoblastoma.