Mechanistic Physiologically Based Pharmacokinetic Models in Development of Therapeutic Monoclonal Antibodies

Abstract

Physiologically based pharmacokinetic (PBPK) models, with integrating the structural, in silico , and in vitro physicochemical data of drugs and the physiological and anatomical features of the body, provide a realistic characterization of the systemic disposition of drugs. Therapeutic monoclonal antibodies (mAbs), as the fastest growing class of new therapeutic molecules, hold great promise for the treatment of a variety of diseases. This chapter first presents the background and history of PBPK models, and then details the principles and methods of PBPK modelling for mAbs. A number of factors should be particularly considered for antibodies in developing PBPK models: distribution space, extravasation, lymphatic distribution, and specific target binding. Then, the chapter discusses the challenges in PBPK modelling, by considering the physiological parameters, extravasation mechanisms, and FcRn function. The chapter also highlights two situations where the minimal PBPK model enacts target‐mediated drug disposition (TMDD) in either plasma or interstitial space.

A Physiologically Based Pharmacokinetic Framework for Quantifying Antibody Distribution Gradients from Tumors to Tumor-Draining Lymph Nodes

“… a L organ (organ-specific lymph flow), 0.2% of organ blood flow [ 25 , 26 ]; b V ISF,PT (PT interstitial fluid volume), 20% of total organ/tissue volume; σ V (vascular reflection coefficient). Organ-specific parameters that were shared by all organ systems include: σ L (lymphatic reflection coefficient) = 0.2 [ 27 ]; L aff (afferent lymph flow) = 0.004 L/h [ 28 ]; L eff (efferent lymph flow) = 0.004 L/h [ 28 ]; V ISF, TDLN (TDLN interstitial fluid volume) = 0.0000584 L, 20% of volume of average LN [ 28 ]; [FcRn] (FcRn concentration in endothelial cells) = 40 uM [ 29 ].…”

“… a L organ (organ-specific lymph flow), 0.2% of organ blood flow [ 25 , 26 ]; b V ISF,PT (PT interstitial fluid volume), 20% of total organ/tissue volume; σ V (vascular reflection coefficient). …”