Antibodies are a highly successful class of biological drugs, with over 50 such molecules approved for therapeutic use and hundreds more currently in clinical development. Improvements in technology for the discovery and optimization of high-potency antibodies have greatly increased the chances for finding binding molecules with desired biological properties; however, achieving drug-like properties at the same time is an additional requirement that is receiving increased attention. In this work, we attempt to quantify the historical limits of acceptability for multiple biophysical metrics of "developability." Amino acid sequences from 137 antibodies in advanced clinical stages, including 48 approved for therapeutic use, were collected and used to construct isotypematched IgG1 antibodies, which were then expressed in mammalian cells. The resulting material for each source antibody was evaluated in a dozen biophysical property assays. The distributions of the observed metrics are used to empirically define boundaries of drug-like behavior that can represent practical guidelines for future antibody drug candidates.monoclonal antibody | developability | biophysical properties | manufacturability | nonspecificity T arget binding is the predominant first concern in development of any drug. However, once a lead molecule attains the desired potency of biological modification, a suite of characteristics termed "developability" assumes critical importance. For monoclonal antibodies, these properties include high-level expression, high solubility, covalent integrity, conformational and colloidal stability, low polyspecificity, and low immunogenicity. The high cost of failing any of these criteria at a late stage in drug development has led to considerable efforts at predicting developability on the basis of sequence motifs and experimentally determined biophysical properties (1-15).In a landmark study of small-molecule drugs over 2,000 molecules with United States Adopted Names (USAN) designations and known to have oral availability were collected and computationally analyzed (16). A simple set of thresholds, encapsulated as the "Lipinski rule of fives," was formulated and has been used by many to prioritize small molecules for entry into clinical development. To date, analogous guiding principles for antibody drugs have not emerged-we therefore endeavor here to do so. By analogy to the Lipinski effort, we first collected the sequences of antibodies that had reached at least phase-2 trials and had USAN or WHO International Nonproprietary Names (INN) designations (137 in total as of the start of this project). As a common basis for comparison of intrinsic variable domain phenotypes we expressed each antibody as the human IgG1 isotype and formulated them in simple Hepes-buffered saline. Each antibody was then subjected to a battery of 12 different biophysical assays in common use for developability assessment.Unexpectedly, for many of the measures the distribution of values was not symmetrically Gaussian, but instead was lon...

(2014) High-throughput screening for developability during early-stage antibody discovery using self-interaction nanoparticle spectroscopy, mAbs, 6:2, 483-492,

Enzymes that catalyze efficient macrocyclization or site-specific ligation of peptides and proteins can enable tools for drug design and protein engineering. Here we describe a protocol to use butelase 1, a recently discovered peptide ligase, for high-efficiency cyclization and ligation of peptides and proteins ranging in size from 10 to >200 residues. Butelase 1 is the fastest known ligase and is found in pods of the common medicinal plant Clitoria ternatea (also known as butterfly pea). It has a very simple C-terminal-specific recognition motif that requires Asn/Asp (Asx) at the P1 position and a dipeptide His-Val at the P1' and P2' positions. Substrates for butelase-mediated ligation can be prepared by standard Fmoc (9-fluorenylmethyloxycarbonyl) chemistry or recombinant expression with the minimal addition of this tripeptide Asn-His-Val motif at the C terminus. Butelase 1 achieves cyclizations that are 20,000 times faster than those of sortase A, a commonly used enzyme for backbone cyclization. Unlike sortase A, butelase is traceless, and it can be used for the total synthesis of naturally occurring peptides and proteins. Furthermore, butelase 1 is also useful for intermolecular ligations and synthesis of peptide or protein thioesters, which are versatile activated intermediates necessary for and compatible with many chemical ligation methods. The protocol describes steps for isolation and purification of butelase 1 from plant extract using a four-step chromatography procedure, which takes ∼3 d. We then describe steps for intramolecular cyclization, intermolecular ligation and butelase-mediated synthesis of protein thioesters. Butelase reactions are generally completed within minutes and often achieve excellent yields.

(2015) High throughput cross-interaction measures for human IgG1 antibodies correlate with clearance rates in mice, mAbs, 7:4, 770-777, DOI: 10.1080/19420862.2015 To link to this article: https://doi.org/10. 1080/19420862.2015 Keywords: high throughput screening, developability, monoclonal antibody, PK, clearance, cross-interaction, self-interaction, non-specificity, stickinessAbbreviations: mAb, monoclonal antibody; PSR, poly specificity reagent; SMP, soluble membrane proteins; CSI-BLI, clone self-interaction-biolayer interferometry; CIC, cross-interaction chromatography; SEC, size exclusion chromatography; AC-SINS, affinity capture self-interaction nanoparticle spectroscopy; SEC, size exclusion chromatographyAlthough improvements in technology for the isolation of potential therapeutic antibodies have made the process increasingly predictable, the development of biologically active monoclonal antibodies (mAbs) into drugs can often be impeded by developability issues such as poor expression, solubility, and promiscuous cross-reactivity. Establishing early stage developability screening assays capable of predicting late stage behavior is therefore of high value to minimize development risks. Toward this goal, we selected a panel of 16 monoclonal antibodies (mAbs) representing different developability profiles, in terms of self-and cross-interaction propensity, and examined their downstream behavior from expression titer to accelerated stability and pharmacokinetics in mice. Clearance rates showed significant rank-order correlations to 2 cross-interaction related assays, with the closest correlation to a non-specificity assay on the surface of yeast. Additionally, 2 self-association assays correlated with each other but not to mouse clearance rate. This case study suggests that combining assays capable of high throughput screening of self-and cross-interaction early in the discovery stage could significantly lower downstream development risks.

Radicals at work: Radical‐mediated thiol‐ene addition of the thiol group of Cys to N‐vinylacetamide gives acetyl‐thialysine (KSAc), a near‐perfect mimic of acetyl‐lysine (see picture). The reaction is highly efficient with near quantitative conversion obtained in short reaction times. The generated KSAc is functionally identical or similar to its native counterpart.