Time-varying clearance (CL) has been recently recognized in U.S. Food and Drug Administration drug labels for oncology monoclonal antibodies. Pembrolizumab population CL at steady state decreased about 20% from the first dose, and individual CL changes varied from 75% decrease to 25% increase, which were correlating with disease conditions. From mechanism of action perspective, this research explored the longitudinal covariate effect on pembrolizumab CL based on data from a phase II/III clinical trial in patients with non-small cell lung cancer. Time courses of sum of the longest tumor dimensions, lymphocyte count, albumin, and lactate dehydrogenase were first characterized separately, and the post hoc parameters of each individual patient were fixed in the subsequent semimechanistically based modeling analysis. Pembrolizumab time-varying CL was assumed to be associated with the patient's sum of the longest tumor dimensions, lymphocyte count, albumin, and lactate dehydrogenase, and tumor-related pembrolizumab CL was assumed to be a fraction of total pembrolizumab CL in the semimechanistically based modeling.
Keywords: longitudinal covariate effect; pembrolizumab; semimechanistically based modeling; time-varying clearance; tumor-related clearance.
Published by Elsevier Inc.