Predicting Human Bioavailability of Subcutaneously Administered Fusion Proteins and Monoclonal Antibodies

Abstract

AbstractThere has been an increasing trend towards subcutaneous (SC) delivery of fusion proteins and monoclonal antibodies (mAbs) in recent years versus intravenous (IV) administration. The prediction of bioavailability is one of the major barriers in clinical translation of SC administered therapeutic proteins due to a lack of reliable in vitro and preclinical in vivo predictive models. In this study, we explored the relationships between human SC bioavailability and physicochemical or pharmacokinetic properties of 20 Fc-or albumin-fusion proteins and 98 monoclonal antibodies. An inverse linear correlation was observed between human SC bioavailability and human intravenous clearance (CL) or isoelectric point (pI). The bioavailability of fusion proteins is more correlated with pI while the bioavailability of mAbs is more correlated with CL. A mAbs with intravenous CL < 4 mL/day/kg is likely to have SC bioavailability > 60%. Multivariate regression models were developed using intravenous CL and pI of a training set (N = 59) as independent variables. The predictive models were validated with an independent test set (N = 33). A linear regression model resulted in 27 among 33 (82%) predictions within 0.8-to 1.2-fold deviations. Overall, this study demonstrated that CL- and pI-based multivariate regression models could be used to predict human SC bioavailability of fusion proteins and mAbs.