Comparison of bioanalytical methods for the quantitation of PEGylated human insulin

Interindividual Variability in the Pharmacodynamic and Pharmacokinetic Characteristics of Recombinant Human Insulin and Insulin Aspart

PURPOSE

The present study compared the interindividual variability in the pharmacodynamic (PD) and pharmacokinetic (PK) properties of a short-acting recombinant human insulin to those of insulin aspart through manual euglycemic glucose clamp tests.

METHODS

Sixty healthy Chinese male volunteers were randomly assigned to receive human insulin or insulin aspart, administered via SC injection (0.2 U/kg). For the evaluation of interindividual variability in PD and PK properties (glucose infusion rate [GIR], insulin concentration [INS]) through euglycemic clamp studies, %CVs were calculated, and PK/PD interindividual variability was compared between the 2 groups.

FINDINGS

The differences between the human insulin and insulin aspart groups in interindividual variabilities in total AUCs of the GIR (19% vs 21%) and INS (14% vs 17%) were not significant. The interindividual variabilities in AUCgir_0-120min, early T_max50%, and AUCins_0-120min were lower in the insulin aspart group than in the human insulin group (22% vs 44%, 21% vs 35%, and 22% vs 28%, respectively; all, P ˂ 0.05), while the interindividual variabilities in the AUCs of GIR_120-600min and INS_120-600min were higher with insulin aspart than with human insulin (29% vs 20%, 51% vs 30%; both, P ˂ 0.05).

IMPLICATIONS

The overall interindividual variability with insulin aspart was similar to that with recombinant human insulin. Yet insulin concentration and metabolic effect during the declining period were more variable with insulin aspart compared to human insulin in these healthy male subjects.

Development and validation of an electrochemiluminescent ELISA for quantitation of oral insulin tregopil in diabetes mellitus serum

AIM

Tregopil, a novel PEGylated human insulin is in clinical development for oral delivery in diabetes treatment. The aim of the study was to develop and validate a sensitive and specific ELISA method for quantitating Tregopil in diabetes subjects on basal Glargine, since most commercially available insulin kits either do not detect Tregopil or show significant reactivity to Glargine.

METHODS

An electrochemiluminescent ELISA was developed and validated for Tregopil quantitation in diabetes serum.

RESULTS

The method has a LLOQ of 0.25 ng/ml, shows minimum cross-reactivity to Glargine and was successfully tested using a subset of samples from Tregopil-dosed Type 1 diabetes mellitus patients.

CONCLUSION

The ELISA method is sensitive and can be used to support accurate measurement of Tregopil with no cross-reactivity to Glargine and its metabolites in clinical studies.

A semi-universal assay platform to quantitate vaccines with potential applications for biotherapeutics

AIM

Biologics development often requires multiple immunoassays to evaluate both assay reagents and potential drug candidates resulting in extensive analytical development.

METHODOLOGY

We developed a semi-universal, 5-layer platform assay on Gyrolab using secondary antispecies or anti-isotype-specific capture and detection antibodies. We applied the assay to several multivalent vaccines.

RESULTS

Method performance exhibited a median accuracy of 110%, reproducibility of 9% CV and intermediate precision of 11% CV. System suitability criteria were met for 92.5% of the samples and only one out of 31 replicate samples exhibited a %CV greater than 20%.

CONCLUSION

The semi-universal Gyrolab assay allowed assay development without reagent labeling. The format could also be translated into a plate-based assay.

Measurement of Pre-Existing IgG and IgM Antibodies against Polyethylene Glycol in Healthy Individuals

Polyethylene glycol (PEG) is a biocompatible polymer that is often attached to therapeutic molecules to improve bioavailability and therapeutic efficacy. Although antibodies with specificity for PEG may compromise the safety and effectiveness of PEGylated medicines, the prevalence of pre-existing anti-PEG antibodies in healthy individuals is unclear. Chimeric human anti-PEG antibody standards were created to accurately measure anti-PEG IgM and IgG antibodies by direct ELISA with confirmation by a competition assay in the plasma of 1504 healthy Han Chinese donors residing in Taiwan. Anti-PEG antibodies were detected in 44.3% of healthy donors with a high prevalence of both anti-PEG IgM (27.1%) and anti-PEG IgG (25.7%). Anti-PEG IgM and IgG antibodies were significantly more common in females as compared to males (32.0% vs 22.2% for IgM, p < 0.0001 and 28.3% vs 23.0% for IgG, p = 0.018). The prevalence of anti-PEG IgG antibodies was higher in younger (up to 60% for 20 year olds) as opposed to older (20% for >50 years) male and female donors. Anti-PEG IgG concentrations were negatively associated with donor age in both females (p = 0.0073) and males (p = 0.026). Both anti-PEG IgM and IgG strongly bound PEGylated medicines. The described assay can assist in the elucidation of the impact of anti-PEG antibodies on the safety and therapeutic efficacy of PEGylated medicines.

Old to new ligand-binding assay method modifications

This article aims to address approaches to ensuring method changes for regulated ligand-binding assays of biologics drugs from old to newer formats and technology are properly understood, characterized and validated to meet current industry expectations and regulatory requirements. Sections in the chapter will include descriptions of different formats of ligand-binding assays, reasons that may drive updating of methods and procedures for qualifying method changes for immunoassays that are designed to support PK and immunogenicity analyses for clinical and nonclinical applications. Case studies from the authors’ experience, as well as literature references will be provided as examples of challenges, as well as providing guidance of when and how to provide smooth transitions of older methods to newer, more robust or sensitive methods as reagents or technology are available.

Use of generic LC–MS/MS assays to characterize atypical PK profile of a biotherapeutic monoclonal antibody

Background: The fully human monoclonal antibody mAb123, which binds to and neutralizes chemokine motif ligand-21 (CCL21) displays a faster clearance in cynomolgus monkey compared with typical IgG kinetics. A direct and an immunoaffinity LC–MS/MS assays were developed to compare with the previously established ligand-binding assays (LBAs). Results: A strong correlation of LC–MS/MS pharmacokinetic data with LBA data confirmed the rapid drug disposition of mAb123 is an intrinsic property of the molecule, rather than interference of anti-mAb123 antibodies in the LBA. Conclusion: The data illustrate that in cases of unexpected results from LBA, application of orthogonal bioanalytical techniques such as LC–MS/MS can help in in interpretation of pharmacokinetic as determined by LBAs.

Toward sensitive and accurate analysis of antibody biotherapeutics by liquid chromatography coupled with mass spectrometry

Remarkable methodological advances in the past decade have expanded the application of liquid chromatography coupled with mass spectrometry (LC/MS) analysis of biotherapeutics. Currently, LC/MS represents a promising alternative or supplement to the traditional ligand binding assay (LBA) in the pharmacokinetic, pharmacodynamic, and toxicokinetic studies of protein drugs, owing to the rapid and cost-effective method development, high specificity and reproducibility, low sample consumption, the capacity of analyzing multiple targets in one analysis, and the fact that a validated method can be readily adapted across various matrices and species. While promising, technical challenges associated with sensitivity, sample preparation, method development, and quantitative accuracy need to be addressed to enable full utilization of LC/MS. This article introduces the rationale and technical challenges of LC/MS techniques in biotherapeutics analysis and summarizes recently developed strategies to alleviate these challenges. Applications of LC/MS techniques on quantification and characterization of antibody biotherapeutics are also discussed. We speculate that despite the highly attractive features of LC/MS, it will not fully replace traditional assays such as LBA in the foreseeable future; instead, the forthcoming trend is likely the conjunction of biochemical techniques with versatile LC/MS approaches to achieve accurate, sensitive, and unbiased characterization of biotherapeutics in highly complex pharmaceutical/biologic matrices. Such combinations will constitute powerful tools to tackle the challenges posed by the rapidly growing needs for biotherapeutics development.