A Systematic Evaluation of the Dosing Regimens for Approved Targeted Therapies and Immune Checkpoint Inhibitors in Metastatic Renal Cell Carcinoma From a Project OPTIMUS Perspective

Targeted therapies and immune checkpoint inhibitors (ICIs) have significantly improved survival outcomes in metastatic renal cell carcinoma (mRCC) but are often associated with high rates of adverse events, leading to dose reductions or treatment discontinuation. The FDA's recent initiative, Project OPTIMUS, emphasizes the importance of optimizing dosing regimens in oncology clinical development, and moves beyond the conventional maximum tolerated dose approach. In this study, we aimed to review and redefine the approved dosing strategies for targeted therapies and ICIs in mRCC from the Project OPTIMUS perspective, including pazopanib, axitinib, cabozantinib, sunitinib, everolimus, and nivolumab. A comprehensive summary of FDA clinical pharmacology reviews and clinical studies performed in routine clinical practice was conducted, alongside model-informed simulations of pharmacokinetic profiles with approved and alternative regimens. Results demonstrated that actual tolerated doses in clinical practice were 46.1% to 86% lower than the approved dosages, with up to 75% of patients requiring dose adjustments. Model-informed simulations suggested that for most targeted therapies, a 14%-50% dose reduction maintained comparable efficacy while improving tolerability. For nivolumab, simulations confirmed adequate drug exposure with the approved flat dose regimens, without an increase of adverse effects. In conclusion, we identified optimized dosing regimens that could improve drug tolerability while maintaining efficacy for approved targeted therapies and ICIs in mRCC. We suggest that these optimized dosing regimens should be considered for use in clinical practice and that the optimal exposure range should be included in drug labels to support pharmacokinetically guided dose individualization in clinical practice.