A Tiered Approach for Characterization to Ensure Quality, Reproducibility, and Long-Term Stability of Critical Reagents in Regulated Bioanalysis to Support PK/ADA/NAb Assays for Biologics and Vaccines Programs

Immunocapture LC-MS methods for pharmacokinetics of large molecule drugs

Implementation of immunocapture LC-MS methods to characterize the pharmacokinetic profile of large molecule drugs has become a widely used technique over the past decade. As the pharmaceutical industry strives for speediness into clinical development without jeopardizing quality, robust assays with generic application across the pipeline are becoming instrumental in bioanalysis, especially in early-stage development. This review highlights the capabilities and challenges involved in hybrid immunocapture LC-MS techniques and its continued applications in nonclinical and clinical pharmacokinetic assay design. This includes a comparison of LC-MS-based approaches to conventional ligand-binding assays and the driving demands in large molecule drug portfolios including growing sensitivity requirements and the unique challenges of new modalities requiring innovation in the bioanalytical laboratory.

Human Cyclophilin B Nuclease Activity Revealed via Nucleic Acid-Based Electrochemical Sensors

Human cyclophilin B (CypB) is oversecreted by pancreatic cancer cells, making it a potential biomarker for early-stage disease diagnosis. Our group is motivated to develop aptamer-based assays to measure CypB levels in biofluids. However, human cyclophilins have been postulated to have collateral nuclease activity, which could impede the use of aptamers for CypB detection. To establish if CypB can hydrolyze electrode-bound nucleic acids, we used ultrasensitive electrochemical sensors to measure CypB's hydrolytic activity. Our sensors use ssDNA and dsDNA in the biologically predominant d-DNA form, and in the nuclease resistant l-DNA form. Challenging such sensors with CypB and control proteins, we unequivocally demonstrate that CypB can cleave nucleic acids. To our knowledge, this is the first study to use electrochemical biosensors to reveal the hydrolytic activity of a protein that is not known to be a nuclease. Future development of CypB bioassays will require the use of nuclease-resistant aptamer sequences.

Prediction of frozen virus stability based on degradation mechanisms, real-time data and modeling

Aim: Critical virus reagents in regulated bioanalytical assays require stability monitoring. Although stability at ultralow frozen temperatures is generally assumed, published data are limited and real-time studies are time consuming. Materials & methods: The authors reviewed literature data, typical mechanisms of molecular degradation, glass transition temperatures of commonly used buffers and available real-time storage data to model frozen virus reagent stability. Results: Storage at ultralow temperatures below the glass transition temperature was critical for virus stability. Modeling of real-time data suggested that virus potency remained within 0.5 log10 of its starting potency at a probability of >99, 90 and 73% after 10, 20 and 30 years, respectively. Conclusion: The study supports the practice of virus storage at -70°C or below for 20–30 years.

Critical reagents for ligand-binding assays: process development methodologies to enable high-quality reagents

Development of biotherapeutics require pharmacokinetic/pharmacodynamic (PK/PD) and immunogenicity assays that are frequently in a ligand-binding assay (LBA) format. Conjugated critical reagents for LBAs are generated conjugation of the biotherapeutic drug or anti-drug molecule with a label. Since conjugated critical reagent quality impacts LBA performance, control of the generation process is essential. Our perspective is that process development methodologies should be integrated into critical reagent production to understand the impact of conjugation reactions, purification techniques and formulation conditions on the quality of the reagent. In this article, case studies highlight our approach to developing process conditions for different molecular classes of critical reagents including antibodies and a peptide. This development approach can be applied to the generation of future conjugated critical reagents.

The importance of quality critical reagents for the entire developmental lifecycle of a biopharmaceutical: a pharmacokinetic case study

Background: High-quality critical reagents are essential to the successful support of biotherapeutic drug development regardless of the analytical platform used for support. The lack of such a reagent, early in the development lifecycle of a biotherapeutic can have detrimental impact on resource and translation of data across development phases. Results: Here, a pharmacokinetic assay case study is shared that illustrates what can occur when there is a lack of a reproducible and sustainable critical reagent early in the development lifecycle of a biotherapeutic. Various assay formats and critical reagents, as well as reagents generation programs, were initiated to find a reagent and assay format which was fit for purpose. Conclusions: Identification of appropriate critical reagents early in the development lifecycle of a biotherapeutic as advantageous.