Establishing in vitro in vivo correlations to screen monoclonal antibodies for physicochemical properties related to favorable human pharmacokinetics

Abstract

Implementation of in vitro assays that correlate with in vivo human pharmacokinetics (PK) would provide desirable preclinical tools for the early selection of therapeutic monoclonal antibody (mAb) candidates with minimal non-target-related PK risk. Use of these tools minimizes the likelihood that mAbs with unfavorable PK would be advanced into costly preclinical and clinical development. In total, 42 mAbs varying in isotype and soluble versus membrane targets were tested in in vitro and in vivo studies. MAb physicochemical properties were assessed by measuring non-specific interactions (DNA- and insulin-binding ELISA), self-association (affinity-capture self-interaction nanoparticle spectroscopy) and binding to matrix-immobilized human FcRn (surface plasmon resonance and column chromatography). The range of scores obtained from each in vitro assay trended well with in vivo clearance (CL) using both human FcRn transgenic (Tg32) mouse allometrically projected human CL and observed human CL, where mAbs with high in vitro scores resulted in rapid CL in vivo. Establishing a threshold value for mAb CL in human of 0.32 mL/hr/kg enabled refinement of thresholds for each in vitro assay parameter, and using a combinatorial triage approach enabled the successful differentiation of mAbs at high risk for rapid CL (unfavorable PK) from those with low risk (favorable PK), which allowed mAbs requiring further characterization to be identified. Correlating in vitro parameters with in vivo human CL resulted in a set of in vitro tools for use in early testing that would enable selection of mAbs with the greatest likelihood of success in the clinic, allowing costly late-stage failures related to an inadequate exposure profile, toxicity or lack of efficacy to be avoided.

Linear pharmacokinetic parameters for monoclonal antibodies are similar within a species and across different pharmacological targets: A comparison between human, cynomolgus monkey and hFcRn Tg32 transgenic mouse using a population-modeling approach

“…5). This trend has been observed previously with a larger dataset of mAbs 32 and suggests that the AC-SINS assay is a useful screening tool to de-select mAbs that have the potential for fast clearance in humans.…”

“…An AC-SINS assay was used to screen 11 of the mAbs in the dataset. An AC-SINS score of >11 has been associated with high self-association 32 . The AC-SINS scores for the subset of mAbs tested from this dataset ranged from 0 to 24, with 3 mAbs exhibiting higher than typical CL having scores of 11–24.…”

“…The mechanism of this non-specificity has not been fully elucidated, but could be in part due to hydrophobicity/ positive charged patches on mAbs 31 . To test this, an in vitro high throughput assay measuring non-specific binding was implemented and used to identify mAbs with increased risk of having fast CL in humans 32 . An AC-SINS assay was used to screen 11 of the mAbs in the dataset.…”

High-throughput retrieval of physical DNA for NGS-identifiable clones in phage display library

“…In conventional antibody drug discoveries, early screening and optimization steps focus on characteristics such as binding activity, potency, and stability for selection of lead constructs, while pharmacokinetic properties which can influence both efficacy and toxicity are typically characterized later in development and on a small number of lead monoclonal antibody constructs. Predicting pharmacokinetic properties of antibodies in the genotypebased screening can reduce the time needed for drug discovery and development by improving the lead monoclonal antibody selection process 33 . TrueRepertoire™ provides a highly accurate consensus sequence of the clones.…”

“…Using the consensus sequence and clonal frequency of the clones, characteristics of clones, including pharmacokinetics of antibodies, can be expected. Therefore, clones can be selected based on genotype-based screening results, and the selected clones can be retrieved by referring to the barcode information of the consensus sequence 7,33,34 . As a representative example of the genotype-based screening through TrueRepertoire™, charge distribution of antibodies can be analyzed by the consensus sequence of the clones, then clones expected to have poor pharmacokinetics can be excluded in the retrieval.…”