Strategies to minimize variability and bias associated with manual pipetting in ligand binding assays to assure data quality of protein therapeutic quantification

Automated ELISA for potency measurements of therapeutic antibodies and antibody fragments

Potency assays are essential for the development and quality control of biopharmaceutical drugs, but they are often a time limiting factor due to manual handling steps and consequently low analytical throughput. On the other hand, automation of potency assays can be challenging due to their complexity and the use of biological materials. ELISA (enzyme-linked immunosorbent assay) is widely used for potency determination and is a good candidate for automation as all ELISA types depend on the same basic steps: coating, blocking, sample incubation, detection, and signal measurement. Nevertheless, ELISA for relative potency measurements still require drug-specific development and assay validation thereby complicating automation efforts. To simplify potency testing by ELISA, we first developed a manual protocol generally applicable to different drugs and then adapted this protocol for automated measurements. We identified unexpected critical parameters which had to be adapted to transfer the manual ELISA to an automated liquid handling system and we demonstrated that gravimetric sample dilution is unnecessary with the automated protocol. Both manual and automated protocols were validated and compared using multiple biotherapeutics. The automated protocol showed similar or higher precision and accuracy when compared to the manual method.

Piston-driven automated liquid handlers

Laboratory capacities are often limited by time-consuming manual repetitive procedures rather than analysis time itself. While modern instruments are typically equipped with an autosampler, sample preparation often follows manual procedures including many labor-intensive, monotonous tasks. Particularly, for a high number of samples, well plates, and low microliter pipetting, manual preparation is error-prone often requiring repeated experiments. Sampling and sample preparation can account for greater analytical variability than instrument analysis. Repetitive tasks such as liquid handling benefit strongly from technological advances and led to the increasing applications of various automated liquid handlers (ALHs). In this review, we discuss the considerations for ALHs in the microliter range and highlight advantages and challenges when transforming from manual to automated workflows. We strongly focused on differences in liquid handling and outlined advantages due to sensor-controlled pipetting. ALHs can substantially improve costs-effectiveness and laboratory capacity. This is a consequence of increased efficiency, and throughput of laboratories while simultaneously raising data quality. Additionally, ALHs can improve safety, documentation of data, and sustainability. While automation requires careful consideration and resource demanding implementation, we believe it offers numerous advantages and can help to transform modern laboratories.

Research on accurate pipetting complementation model for high-throughput molecular detection platform

The incidence of infectious diseases has risen in recent years, leading to a significant surge in the demand for medical molecular detection. High-throughput molecular detection platforms play a crucial role in facilitating rapid and efficient molecular detection. Among the various techniques employed in high-throughput molecular detection, microliquid transfer stands out as one of the most frequently utilized methods. However, ensuring the accuracy of liquid transfer poses a challenge due to variations in the physical and chemical properties of different samples and reagents. In this study, a pipetting complementation model was developed specifically for the serum, paraffin oil, and throat swabs. The aim was to enhance the transfer accuracy of diverse liquids in the context of high-throughput molecular detection, ultimately ensuring detection reliability and stability. The experimental findings revealed notable improvements in pipetting accuracy after compensating for the three liquids. In particular, the pipetting error rates decreased by 52.5, 96, and 71.4% for serum, paraffin oil, and throat swabs, respectively. These results underscore the model's effectiveness in providing reliable support for the precise transfer of liquids on the high-throughput molecular detection platform.

Improving the performance and versatility of microfluidic thread electroanalytical devices by automated injection with electronic pipettes: a new and powerful 3D-printed analytical platform

Microfluidic cotton thread-based electroanalytical devices (μTEDs) are analytical systems with attractive features such as spontaneous passive flow, low cost, minimal waste production, and good sensitivity. Currently, sample injection in µTEDs is performed by hand using manual micropipettes, which have drawbacks such as inconstant speed and position, dependence of skilled analysts, and need of physical effort of operator during prolonged times, leading to poor reproducibility and risk of strain injury. As an alternative to these inconveniences, we propose, for the first time, the use of electronic micropipettes to carry out automated injections in µTEDs. This new approach avoids all disadvantages of manual injections, while also improving the performance, experience, and versatility of µTEDs. The platform developed here is composed by three 3D-printed electrodes (detector) attached to a 3D-printed platform containing an adjustable holder that keeps the electronic pipette in the same x/y/z position. As a proof-of-concept, both injection modes (manual and electronic) were compared using three model analytes (nitrite, paracetamol, and 5-hydroxytryptophan) on µTED with amperometric detection. As result, improved analytical performance (limits of detection between 2.5- and 5-fold lower) was obtained when using electronic injections, as well as better repeatability/reproducibility and higher analytical frequencies. In addition, the determination of paracetamol in urine samples suggested better precision and accuracy for automated injection. Thus, electronic injection is a great advance and changes the state-of-art of µTEDs, mainly considering the use of more modern and versatile electronic pipettes (wider range of pre-programmed modes), which can lead to the development of even more automated systems.

Assessing variations in manual pipetting: An under-investigated requirement of good laboratory practice

Pipettes are essential tools for biomedical and analytical laboratories, analogous to workstations for computer scientists. Variation in pipetting is a known unknown, as it is generally accepted that variations exist, but thus far, there have been limited studies on the extent of these variations in practice. In this mini-review, we highlight how manual pipetting is a key technique in the laboratory, and, although simple, inaccuracy and imprecision exist. If variations are not adequately addressed, errors can be compounded and consequently compromise data quality. Determination of the accuracy and precision of manual pipetting is straightforward, and here we review two common approaches that use gravimetry and spectrophotometry as readouts. We also provide detailed protocols for determination of accuracy and precision using manual single and multi-channel pipettes. These simple-to-use methods can be used by any laboratory for competency training and regular checks. Having a common protocol for evaluation of variation will also enable cross-laboratory comparison and potentially facilitate establishment of a reference value of acceptable ranges for operator error. Such a value could be of relevance to the scientific community for benchmarking and assuring good laboratory practice.

Use of capillary-mediated vitrification to produce thermostable, single-use antibody conjugates as immunoassay reagents

The performance of enzyme-linked immunoassays is directly dependent on the storage, handling, and long-term stability of the critical reagents used in the assay. Currently, antibody reagents are routinely stored as concentrated, multi-use, frozen aliquots. This practice results in material waste, adds complexity to laboratory workflows, and can compromise reagents via cross-contamination and freeze-thaw damage. While refrigeration or freezing can slow down many degradation processes, the freezing process itself can have damaging effects, including introduction of aggregation and microheterogeneity. To address these challenges, we evaluated the application of capillary-mediated vitrification (CMV) as a tool for storing antibody reagents in a thermostable, single-use format. CMV is a novel biopreservation method that enables vitrification of biological materials without freezing. Using an anti-human IgG-alkaline phosphatase conjugate as a model system, we prepared CMV-stabilized aliquots which were stored in a single-use format at temperatures ranging from 25 to 55 °C for up to 3 months. Each stabilized aliquot contained enough antibody to perform a single assay run. We evaluated the assay performance and functional stability of the CMV-stabilized reagents using a plate-based ELISA. Assays run using the CMV stabilized reagents exhibited good linearity and precision that was comparable to results obtained with a frozen control. Throughout the stability study, the maximum signal and EC50s observed for ELISAs run using CMV-stabilized reagents were generally consistent with those obtained using a frozen control. These results indicate that the CMV process has the potential to improve both reagent stability and long-term assay performance, while also reducing reagent waste and simplifying assay workflows.

Review of the Clinical Pharmacokinetics, Efficacy and Safety of Pembrolizumab

BACKGROUND

Treatment of various types of cancer has been improved significantly with the discovery of biologic drugs that act as immune checkpoint inhibitors (ICIs). Pembrolizumab is a humanized monoclonal anti-PD-1 antibody currently approved for the treatment of a wide range of tumors, with more indications still being investigated in ongoing clinical trials.

OBJECTIVE

The aim of this paper is to present all currently available data regarding pembrolizumab pharmacokinetic and pharmacodynamic characteristics. Also, the possibility of using predicative biomarkers to monitor patients during cancer treatment is discussed.

METHODS

Database research was carried out (PubMed, ScienceDirect). Information was gathered from original articles, the European Medicines Agency datasheets and results from clinical trials.

RESULTS

This review summarizes present-day knowledge about the pharmacokinetics, different modeling approaches and dosage regimens, efficacy and safety of pembrolizumab and therapeutic monitoring of disease progression.

CONCLUSION

This review points out consistent pharmacokinetic characteristics of pembrolizumab in various cancer patients, the lack of pharmacokinetic-pharmacodynamic/outcome relationships, the need of adequate biomarkers predicting treatment success. Hence, there is a clear necessity for more data and experience in order to optimize pembrolizumab treatment for each individual patient.

Evaluating and minimizing batch effects in metabolomics

Determining metabolomic differences among samples of different phenotypes is a critical component of metabolomics research. With the rapid advances in analytical tools such as ultrahigh-resolution chromatography and mass spectrometry, an increasing number of metabolites can now be profiled with high quantification accuracy. The increased detectability and accuracy raise the level of stringiness required to reduce or control any experimental artifacts that can interfere with the measurement of phenotype-related metabolome changes. One of the artifacts is the batch effect that can be caused by multiple sources. In this review, we discuss the origins of batch effects, approaches to detect interbatch variations, and methods to correct unwanted data variability due to batch effects. We recognize that minimizing batch effects is currently an active research area, yet a very challenging task from both experimental and data processing perspectives. Thus, we try to be critical in describing the performance of a reported method with the hope of stimulating further studies for improving existing methods or developing new methods.

Development of an Aptamer-Based Electrochemical Microfluidic Device for Viral Vaccine Quantitation

Global deployment of vaccines poses significant challenges in the distribution and use of the accompanying immunoassays, one of the standard methods for quality control of vaccines, particularly when establishing assays in countries worldwide to support testing/release upon importation. This work describes our effort toward developing an integrated, portable device to carry out affinity assays for viral particles quantification in viral vaccines by incorporating (i) aptamers, (ii) microfluidic devices, and (iii) electrochemical detection. We generated and characterized more than eight aptamers against multiple membrane proteins of cytomegalovirus (CMV), which we used as a model system and designed and fabricated electrochemical microfluidic devices to measure CMV concentrations in a candidate vaccine under development. The aptamer-based assays provided a half maximal effective concentration, EC₅₀, of 12 U/mL, comparable to that of an ELISA using a pair of antibodies (EC₅₀ 60 U/mL). The device measured relative CMV concentrations accurately (within ±10% bias) and precisely (11%, percent relative standard deviation). This work represents the critical first steps toward developing simple, affordable, and robust affinity assays for global deployment without the need for sensitive equipment and extensive analyst training.

Semi-automation of process analytics reduces operator effect

The aim of this study was to semi-automate process analytics for the quantification of common impurities in downstream processing such as host cell DNA, host cell proteins and endotoxins using a commercial liquid handling station. By semi-automation, the work load to fully analyze the elution peak of a purification run was reduced by at least 2.41 h. The relative standard deviation of results among different operators over a time span of up to 6 months was at the best reduced by half, e.g. from 13.7 to 7.1% in dsDNA analysis. Automation did not improve the reproducibility of results produced by one operator but released time for data evaluation and interpretation or planning of experiments. Overall, semi-automation of process analytics reduced operator-specific influence on test results. Such robust and reproducible analytics is fundamental to establish process analytical technology and get downstream processing ready for Quality by Design approaches.

Spectrophotometry in modular microfluidic architectures

Assays for chemical biomarkers are a vital component in the ecosystem of noninvasive disease state assessment, many of which rely on quantification by colorimetric reactions or spectrophotometry. While modern advances in microfluidic technology have enabled such classes of devices to be employed in medical applications, the challenge has persisted in adapting the necessary tooling and equipment to integrate spectrophotometry into a microfluidic workflow. Spectrophotometric measurements are common in biomarker assays because of straightforward acquisition, ease of developing the assay's mechanism of action, and ease of tuning sensitivity. In this work, 3D-printed, discrete microfluidic elements are leveraged to develop a model system for assaying hyaluronidase, a urinary biomarker of bladder cancer, via absorbance spectrometry of gold nanoparticle aggregation. Compared to laboratory microtiter plate-based techniques, the system demonstrates equivalent performance while remaining competitive in terms of resource and operation requirements and cost.

Field-compatible protocol for detecting tetracyclines with bioluminescent bioreporters without pipetting steps

Whole-cell bioreporters are living organisms and thus using them for detecting environmental contaminants would reflect biological effects of these pollutants. However, bioreporters are not widely used in field studies. Many of the bioreporter field protocols are suitable for liquid samples or include pipetting steps, which is a demanding task outside the laboratory. We present a bioreporter protocol without pipetting or sample type requirements. The protocol utilizes polyester swabs, commonly used in cleanroom technology. As an example contaminant, we used tetracycline and generated test samples with known concentrations up to the maximum tetracycline residue limit of milk set by the European Union (EU) regulation. The matrices of the test samples were Milli-Q water, milk and soil. The swabs were first dipped in the bioreporter cell cultures and then to test samples and luminescence was measured after incubation. The standard deviation of measurements from ten replicate swabs was in the same range as commonly in pipetting protocols (4-19%). The test samples with lowest tetracycline concentration (5 ng mL^-1 ) were distinguished from the control samples (0 ng mL^-1 tetracycline). Our results show that swabs can be used together with luminescent whole cell bioreporters, making it possible to conduct the measurements in field conditions.

Evaluation of a digital dispenser for direct curve dilutions in a vaccine potency assay

Dilutions are a common source of analytical error, both in terms of accuracy and precision, and a common source of analyst mistakes. When serial dilutions are used, errors compound, even when employing laboratory automation. Direct point dilutions instead of serial dilutions can reduce error but is often impractical as they require either large diluent volumes or very small sample volumes when performed with traditional liquid handling equipment. We evaluated preparation of dilution curves using a picoliter digital dispenser, the HP, Inc. / TECAN D300 which is capable of accurately delivering picoliter volumes directly into sample wells filled with assay diluent. Dilution linearity and variability of the direct dilutions were similar to or less than those generated with a traditional liquid handler as measured using a fluorophore assay and an ELISA used to measure vaccine potency. Minimum concentrations for detergent in the dispensed sample were identified but no correlation with detergent characteristics was observed. The tolerance to protein in the sample was evaluated as well with up to 5% BSA having no impact on dispense linearity and precision. We found the digital dispenser to reduce automation complexity while maintaining or improving assay performance in addition to facilitating complex plate lay-outs.

Reduction of dilution error in ELISAs using an internal standard

Background: Dilution bias is a major cause of immunoassay variability due to the lack of an internal standard to determine the true versus the expected dilution value. Methodology: We used an internal control to measure dilution bias in an ELISA. Acridine-orange was added at the first dilution step and monitored throughout dilutions. Assay results were corrected using the fluorescent signal ratio between samples and reference. Acridine dilution correlated with analyte-specific assay measurements (R2 = 0.987). Correction of assay results with the measured dilution factor improved both accuracy and precision resulting in a reduction of >50% %CV reduction. Conclusion: Dilution correction can significantly improve accuracy and precision of immunoassays. Additional control strategies may further mitigate other sources of variability.

Serum sample stability in ligand-binding assays: challenges in assessments of long-term, bench-top and multiple freeze–thaw

Chris Macaraeg has been a lead scientist for method development, validation, and study support intended for regulated pre-clinical/clinical studies within the Pharmacokinetics and Drug Metabolism department at Amgen Inc, Thousand Oaks, CA. He joined Amgen in 2006. His expertise also includes automation and method transfer to CROs. Chris received his BS degree in Physiological Science and Neuroscience from the University of California, Los Angeles, CA and MS in Forensic Science from Pace University, New York, NY.

Stability of therapeutic proteins in biological matrix is an important parameter to evaluate in bioanalytical support of regulated nonclinical or clinical studies. Despite industry guidance publications, many questions still arise as to how these practices are implemented to establish therapeutic protein stability in bioanalytical method validations. This article presents findings from long-term, bench-top and freeze–thaw stability assessments for three therapeutic monoclonal antibodies using either ELISA or electrochemiluminescent technology. Studies illustrate the principles and challenges in stability tests which represent scenarios that samples will likely encounter during sample analysis. Thoughtful consideration of each study requirements and a fit-for-purpose approach is essential in successful establishment of the sample stability parameters in method validation.

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.

Automating bioanalytical sample analysis through enhanced system integration

BACKGROUND

In the bioanalytical laboratory, challenges associated with manual, repetitive, labor-intensive processes can be addressed by powerful automated liquid handlers; however, their implementation has been difficult due to lack of efficient integration into laboratory workflows. Faster throughput is afforded to ligand binding assay (LBA) technologies via enhanced automation, but the upstream sample processing still remains a bottleneck. To be truly efficient, these technologies must be incorporated into a laboratory information management system (LIMS) to streamline data analysis and reporting.

RESULTS

Three off-the-shelf technologies that aid in improving bioanalytical laboratory efficiencies were utilized with minimal customization to streamline the sample analysis process. Information extracted via a sequence file from the LIMS run was utilized to perform the sample processing on the automated liquid handler. A file conversion tool converted the sequence files that allowed for sample processing and preparing the assay ready plate. The plate was then transferred to the LBA microfluidics platform to run the experiments. The integration was tested using a LBA PK assay that demonstrated good sample dilution and assay performance.

CONCLUSION

We successfully integrated LIMS with an automated liquid handler and a microfluidics platform to automate the sample analysis process in the bioanalytical laboratory. The utilization of off-the-shelf technologies with minimal customization requires minimal resources from laboratory scientists. It may be possible to implement this approach for other analytical platforms.

Laboratory automation of high-quality and efficient ligand-binding assays for biotherapeutic drug development

Background: Regulated bioanalytical laboratories that run ligand-binding assays in support of biotherapeutics development face ever-increasing demand to support more projects with increased efficiency. Laboratory automation is a tool that has the potential to improve both quality and efficiency in a bioanalytical laboratory. The success of laboratory automation requires thoughtful evaluation of program needs and fit-for-purpose strategies, followed by pragmatic implementation plans and continuous user support. Results: In this article, we present the development of fit-for-purpose automation of total walk-away and flexible modular modes. We shared the sustaining experience of vendor collaboration and team work to educate, promote and track the use of automation. Conclusion: The implementation of laboratory automation improves assay performance, data quality, process efficiency and method transfer to CRO in a regulated bioanalytical laboratory environment.

A generic template for automated bioanalytical ligand-binding assays using modular robotic scripts in support of discovery biotherapeutic programs

Background: Sample dilution and reagent pipetting are time-consuming steps in ligand-binding assays (LBAs). Traditional automation-assisted LBAs use assay-specific scripts that require labor-intensive script writing and user training. Results: Five major script modules were developed on Tecan Freedom EVO liquid handling software to facilitate the automated sample preparation and LBA procedure: sample dilution, sample minimum required dilution, standard/QC minimum required dilution, standard/QC/sample addition, and reagent addition. The modular design of automation scripts allowed the users to assemble an automated assay with minimal script modification. The application of the template was demonstrated in three LBAs to support discovery biotherapeutic programs. Conclusion: The results demonstrated that the modular scripts provided the flexibility in adapting to various LBA formats and the significant time saving in script writing and scientist training. Data generated by the automated process were comparable to those by manual process while the bioanalytical productivity was significantly improved using the modular robotic scripts.

Automate it: ligand-binding assay productivity in a discovery bioanalytical setting

In multiple industries, including the biopharmaceutical industry, automation is synonymous with increased productivity. Environments with high-throughput needs commonly employ automation for efficiency. However, in a discovery bioanalytical ligand-binding assay laboratory setting where the focus is not necessarily on sample analysis throughput, but instead on assay development and characterization, is automation applicable? Can automation enhance productivity when tasks are more customized than routine? In this Perspective we review the different categories of automation with ligand-binding assays with these questions in mind. In considering whether automation technology has progressed far enough to result in a positive return in investment in the discovery setting, the resource investment required to operate in this space was contrasted with the gain in productivity. In our opinion, technology advancements in automated technology platforms, and especially personal automation, have allowed these categories to strike the right balance for investment in the discovery laboratory setting.

Specific method validation and sample analysis approaches for biocomparability studies of denosumab addressing method and manufacture site changes

Manufacturing changes during a biological drug product life cycle occur often; one common change is that of the manufacturing site. Comparability studies may be required to ensure that the changes will not affect the pharmacokinetic properties of the drug. In addition, the bioanalytical method for sample analysis may evolve during the course of drug development. This paper illustrates the scenario of both manufacturing and bioanalytical method changes encountered during the development of denosumab, a fully human monoclonal antibody which inhibits bone resorption by targeting RANK Ligand. Here, we present a rational approach to address the bioanalytical method changes and provide considerations for method validation and sample analysis in support of biocomparability studies. An updated and improved ELISA method was validated, and its performance was compared to the existing method. The analytical performances, i.e., the accuracy and precision of standards and validation samples prepared from both manufacturing formulation lots, were evaluated and found to be equivalent. One of the lots was used as the reference standard for sample analysis of the biocomparability study. This study was sufficiently powered using a parallel design. The bioequivalence acceptance criteria for small molecule drugs were adopted. The pharmacokinetic parameters of the subjects dosed with both formulation lots were found to be comparable.

Validation and life-cycle management of a quantitative ligand-binding assay for the measurement of Nulojix®, a CTLA-4–Fc fusion protein, in renal and liver transplant patients

Background: Nulojix® is a fusion protein composed of the Fc portion of a human IgG1 linked to the extracellular modified domain of CTLA-4. Nulojix differs from another Bristol Myers Squibb product, Orencia® by two amino acids and was approved by the FDA on 15 June 2011 for the prophylaxis of organ rejection in adult patients receiving kidney transplant. Results: A sandwich ELISA utilizing two monoclonal antibodies against CTLA-4 was employed for Nulojix quantification and pharmacokinetic analysis. At least 17 analysts have qualified on the assay and contributed to reportable results over the last 7 years. In-study accuracy and precision demonstrate suitable performance: %bias within -4 to 4%, %CV ≤13% and total error within 6–15%. Incurred sample reanalysis was completed in applicable disease-state populations. The assay was automated and validated in additional clinical matrices (ascites and urine) and Nulojix quantification was validated in the presence of clinically relevant co-administered compounds. In 2011, the biotinylation procedure was modified meriting a regression change (quadratic to 4-parameter logistic) and associated partial validation. Conclusion: This long-term pharmacokinetic program provides a good example of the dynamic clinical environment and adaptation requirements of ligand-binding assays.

Method transfer for ligand-binding assays: recommendations for best practice

To support clinical trials, bioanalytical methods are often transferred from one laboratory to another. With the rising number of large-molecule therapeutic proteins submitted for US FDA approval, the demand for large-molecule bioanalytical support and, subsequently, method transfer increases. Ligand-binding assays are the methods most commonly used to quantify endogenous and therapeutic proteins for the assessment of biomarkers and pharmacokinetic parameters. The goal of this review is to provide an overview of ligand-binding assay method transfer, essential parameters for partial method validation and to lay out a strategy to increase the chance of success. The recommendations herein are based on a summary of current publications and the authors' specific experiences, to help increase workload efficiency, maintain positive collaborations with partners and meet program timelines.

Quality assessment of bioanalytical quantification of monoclonal antibody drugs

Monoclonal antibody biotherapeutics are developed to bind to a specific target to affect the target’s biological effect. Reliable measurements of monoclonal antibodies in biological fluids using ligand-binding assays are vital for understanding the pharmacokinetic and pharmacodynamic relationships for efficacy/safety evaluations and dose-regimen selection. The method should be properly characterized and demonstrate adequate assay performance to generate credible data for the right decision making at each specific stage, with considerations on the constraints of timeline, reagent availability and assay caveats. Quality assessment of the assay performance should be based on whether the method is ‘fit-for-use’ to meet the objectives of the study. The basic industrial requirements and recent trends in method and data quality of ligand-binding assays for drug exposure studies at various development stages are discussed.

Bioanalytical considerations in the comparability assessment of biotherapeutics

Comparison of biotherapeutic products before and after manufacturing changes is required to show that the products are highly similar. Besides in vitro assessment on the critical quality attributes and potency, biocomparability studies are sometimes required to demonstrate similarities in pharmacokinetic and pharmacodynamic characteristics. The complex and diverse nature of biotherapeutics requires multifaceted considerations in the biocomparability study design, bioanalytical measurements of drug concentrations and/or pharmacodynamic responses, immunogenicity analysis, data interpretation and decision making. A major perspective is to understand the structure and biological functions of the biotherapeutics in relation to the indication. Issues of a common standard and the importance of the use of ligand-binding assays that are sensitive to structural changes are discussed. It would not be possible to use the same process and one-size-fit-all criteria for biocomparability studies of all biologics. Previous examples from industry and our experience of the bioanalytical considerations for fit-for-purpose pharmacokinetic support and immunogenicity assessments are presented.