C-Terminal Lysine Processing of IgG in Human Suction Blister Fluid: Implications for Subcutaneous Administration

• DOI: 10.1021/acs.molpharmaceut.2c00506
• Publication Date: 2022-09-16T17:25:16Z
• Authors: Luladey Ayalew; Phyllis Chan; Zhilan Hu; Amy Shen; Eileen Duenas; Whitney Kirschbrown; Arthur J. Schick; Yan Chen; Michael T. Kim
• Keywords: Critical quality attributes

C-terminal lysine (CTK) is often classified as a potential critical quality attribute for therapeutic antibodies being developed subcutaneous (SC) administration because of its to impact antibody SC bioavailability/pharmacokinetics (PK). This classification both inflates development costs and increases comparability risks antibodies. However, prior risk assessments CTK have not fully considered biotransformation in the space, which may play an important role given that circulating carboxypeptidases humans rapidly process on intravenously administered Here, biofluid derived from human space was investigated. The representative fluid sampled 10 healthy subjects using suction blister method. Glycosylated containing high levels (expressed carboxypeptidase D CRISPR/Cas9 knockout CHO cell line) incubated collected fluids (SBFs), recovered cognate antigen pulldowns, characterized remaining intact reduced liquid chromatography-mass spectrometry (LC-MS) analysis. processing (i.e., activity) evident all SBF exhibited first-order kinetics with rate constants 2.18 ± 0.57 d-1 (at 37 °C). PK simulations integrated pathways their associated were subsequently performed range clinically observed parameters antibodies, including atezolizumab- pertuzumab-specific parameters. content (even up 100%) outcomes such bioavailability Ctrough modest (<14%) combinations tested sensitivity study forms cornerstone data package derisking liability programs highlights usefulness considering during product criticality assessments.