Influence of physiochemical properties on the subcutaneous absorption and bioavailability of monoclonal antibodies

Abstract

Many therapeutic monoclonal antibodies (mAbs) were initially developed for intravenous (IV) administration. As a means to improve mAb drug-ability and the patient experience, subcutaneous (SC) administration is an increasingly important delivery route for mAbs. Unlike IV administration, bioavailability limitations for antibodies have been reported following SC injection and can dictate whether a mAb is administered via this parenteral route. The SC bioavailability of antibodies has been difficult to predict, and it can be variable and partial, with values ranging from ~50% to 100%. The mechanisms leading to the incomplete bioavailability of some mAbs relative to others are not well understood. There are some limited data that suggest the physiochemical properties inherent to a mAb can contribute to its SC absorption, bioavailability, and in vivo fate. In this study, we evaluated the integrated influence of multiple mAb physiochemical factors on the SC absorption and bioavailability of six humanized mAbs in both rats and cynomolgus monkeys. We demonstrate the physiochemical properties of mAbs are critical to their rate and extent of SC absorption. The combination of high positive charge and hydrophobic interaction significantly reduced the rate of the evaluated mAb’s SC absorption and bioavailability. Reduction or balancing of both these attributes via re-engineering the mAbs restored desirable properties of the molecules assessed. This included reduced association with SC tissue, improvements in mAb absorption from the SC space and overall SC bioavailability. Our findings point to the importance of evaluating the relative balance between various physiochemical factors, including charge, hydrophobicity, and stability, to improve the SC drug-ability of mAbs for selecting or engineering mAbs with enhanced in vivo absorption and bioavailability following SC administration.

Discovery-stage identification of drug-like antibodies using emerging experimental and computational methods

“…Recent studies have also investigated individual problematic antibodies as well as larger sets of more diverse mAbs and revealed various physicochemical properties that are associated with poor PK profiles. 74,118,130 Evaluation of an extensive dataset of 61 antibodies and their measured clearance rates in cynomolgus monkeys confirmed previous reports that antibody IgG properties such as pI and hydrophobic index were weakly correlated with clearance values. 74 However, the sum of CDRs L1, L3, and H3 hydrophobic index scores and the charge of the variable regions at pH 5.5 were found to discriminate between antibodies with high and low clearance with 75-86% accuracy.…”

“…Based on previous studies that found connections between antibody properties and bioavailability, [132][133][134] six antibodies were recently investigated in depth. 130 Multiple antibody properties were found to affect subcutaneous bioavailability, including polyspecificity, aggregation propensity, and thermal stability. Additionally, antibody variants with reduced local positive charge, higher specificity, higher thermal stability, and reduced aggregation potential had more favorable measured bioavailability.…”

Pharmacokinetic Developability and Disposition Profiles of Bispecific Antibodies: A Case Study with Two Molecules

“…As a means to mitigate poor pharmacokinetics for mAbs, several studies have reported leveraging preclinical in vivo and in vitro physiochemical characterization-based PK developability strategies during the discovery process [ 8 , 9 , 10 ]. These approaches have been used to improve the probability of success by selecting or engineering mAbs with increased stability (physical, chemical, and thermal stabilities) and lower non-specific or unintended interactions [ 11 , 12 ]. Improving the stability and lowering the risk of unintended interactions, in turn provides enhanced human exposure profiles to support the intended dose and frequency of administration.…”

Impact of IgG subclass on molecular properties of monoclonal antibodies

“…Samples were eluted with a 20-minute linear gradient into 25 mM potassium phosphate, pH 6.8, 20% isopropanol. Hydrophobicity interaction potential (HIP%) was calculated based on % retention time over gradient as reported by Datta-Mannan et al 44 …”