Weight-Based Pembrolizumab Dosing at 4 mg/kg Every 6 Weeks Leads to Exposures Below Approved Doses with Unestablished Efficacy: A Pharmacokinetic Model-Based Simulation Analysis

Pharmacokinetic modeling suggests pembrolizumab 4 mg/kg Q6W IV results in reduced exposures with an uncertain impact upon efficacy. Participants with lower body weight were increasingly impacted, with meaningful exposure reductions below the clinically established threshold doses of 400 mg Q6W, 200 mg Q3W, and 2 mg/kg Q3W IV. In the absence of robust clinical data on pembrolizumab efficacy at doses with exposures below those of the approved dosing regimens, weight-based dosing at 4 mg/kg Q6W poses a potential risk to treatment efficacy.