Attribution of the discrepancy between ELISA and LC-MS/MS assay results of a PEGylated scaffold protein in post-dose monkey plasma samples due to the presence of anti-drug antibodies

Development and Validation of an ADA-Tolerant Assay for Quantification of an Exatecan-Based ADC in Monkey Plasma

BACKGROUND

The development of an anti-drug antibody (ADA)-tolerant pharmacokinetic (PK) assay is important when the drug exposure is irrelevant to toxicity in the presence of ADA. We aimed to develop and validate an ADA-tolerant assay for an exatecan-based antibody-drug conjugate (ADC) in monkey plasma.

RESULTS

The assay tolerated 5.00 µg/mL of ADA at 12 µg/mL of ADC. Its accuracy and precision results satisfied the acceptance criteria. Furthermore, the assay was free from hook and matrix effects and exhibited good dilutional linearity. Additionally, the ADC in plasma samples was stable under different storage conditions.

METHOD

An ADA-tolerant ADC assay was configured with an anti-payload antibody for capture, and a drug-target protein combined with a horseradish peroxidase (HRP)-labeled antibody against a drug-target-protein tag for detection. Samples were firstly acidified to dissociate drug and ADA complexes, and to convert the carboxylate form to the lactone form of exatecan molecules; then, the ADAs in the samples were removed with a naked antibody-coated microplate. The treated samples were further incubated with coated anti-payload antibody and captured ADC molecules were quantified by the detection reagent. The developed assay was optimized and validated against regulatory guidelines.

CONCLUSIONS

The assay met both methodological and sample-related ADA tolerance requirements, and was applicable to a nonclinical study in cynomolgus monkeys.

A picogram BA-ELISA quantification assay for rLj-RGD3, a platelet fibrinogen receptor antagonist, in the rat plasma and its application to a pharmacokinetic study

rLj-RGD3, a new member of the RGD (Arginine-Glycine-Aspartate)-motif toxin protein family obtained from Lampetra japonica by means of recombinant DNA techniques, has been demonstrated to be a platelet fibrinogen receptor antagonist and holds potential as a drug candidate for a specific indication. The present article reports an innovative validated highly sensitive and specific biotin-avidin enzyme linked immunosorbent assay (BA-ELISA) to provide a bio-analytical method for pharmacokinetic (PK) studies of rLj-RGD3. The concentration of picogram level rLj-RGD3 in rat plasma was measured using the developed double sandwich BA-ELISA assay, which used two mouse anti-rLj-RGD3 monoclonal antibodies that recognize different epitopes for capture and detection. This method was verified to be highly specific (blank plasma did not interfere with detection), precise (RSD <15%), and accurate (86%-113%). Absolute recovery was in the 94%-119% range. The calibration curve showed good linearity within the 50 to 1600 pg/mL range. The LOQ was as low as 50 pg/mL. The above validated assay was successfully employed to assess PK of rLj-RGD3 in rats. After i.v. and s.c. dosing with 30 μg/kg, the rLj-RGD3 plasma concentration declined bi-exponentially with time. This decay was best fitted to a two-compartment model. In conclusion, the BA-ELISA method described here meets all requirements for PK studies of rLj-RGD3 with an effective pharmacological dose in the μg/kg BW range.

Therapeutic drug monitoring of immune checkpoint inhibitors: based on their pharmacokinetic properties and biomarkers

As a new means of oncology treatment, immune checkpoint inhibitors (ICIs) can improve survival rates in patients with resistant or refractory tumors. However, there are obvious inter-individual differences in the unsatisfactory response rate, drug resistance rate and the occurrence of immune-related adverse events (irAE). These questions have sparked interest in researchers looking for a way to screen sensitive populations and predict efficacy and safety. Therapeutic drug monitoring (TDM) is a way to ensure the safety and effectiveness of medication by measuring the concentration of drugs in body fluids and adjusting the medication regimen. It has the potential to be an adjunctive means of predicting the safety and efficacy of ICIs treatment. In this review, the author outlined the pharmacokinetic (PK) characteristics of ICIs in patients. The feasibility and limitations of TDM of ICIs were discussed by summarizing the relationships between the pharmacokinetic parameters and the efficacy, toxicity and biomarkers.

Sex Differences in Intestinal P-Glycoprotein Expression in Wistar versus Sprague Dawley Rats

Wistar and Sprague Dawley are the most common strains of rat used in pharmaceutical research and are used interchangeably in pre-clinical drug development. No studies have assessed whether Wistar and Sprague Dawley rats are equivalent in the gastrointestinal factors that influence oral drug absorption, specifically in relation to intestinal transporters. Enzyme-linked immunosorbent assay (ELISA) and liquid chromatography–tandem mass spectrometry (LC-MS/MS) are two reliable methods for quantifying intestinal protein levels with their own distinct advantages and limitations. In this study, P-glycoprotein (P-gp), a key efflux transporter, was quantified using ELISA and LC-MS/MS along the complete intestinal tract of male and female Wistar and Sprague Dawley rats. This work presents that Sprague Dawley rats have innately higher baseline P-gp expression than Wistar rats. Significant sex differences in P-gp expression were identified in the jejunum, ileum and colon between male and female Wistar rats using both techniques, with males exhibiting higher P-gp levels. Sprague Dawley rats showed no sex differences in P-gp expression through ELISA and LC-MS/MS. Both methods demonstrated similar trends for P-gp quantification, but ELISA could offer faster data acquisition. Our findings report significant sex differences between the strains and highlight that Wistar and Sprague Dawley rats are not equivalent in their P-gp expression. As humans exhibit distinct sex differences in intestinal P-gp levels, Wistar rats may therefore be a more suitable pre-clinical animal strain to model oral drug absorption of P-gp substrates in male and female subjects.

Heat pre-treatment can abolish anti-drug antibody interference in ligand binding pharmacokinetic assays

Anti-drug antibodies (ADAs) can interfere with ligand binding assays (LBAs) by binding to epitopes recognized by the assay antibodies or by preventing assay antibody binding through steric hindrance. This can lead to underestimation of total drug concentration in pharmacokinetic (PK) samples which can confound decisions during drug development. We hypothesized that ADA interference in LBAs can be removed by sample heat pre-treatment. We heat pre-treated ADA-spiked samples by incubating them in a shallow water bath at 56–100 °C for 5–30 min prior to measuring the samples by a traditional electrochemiluminescence (ECL) assay. Heat pre-treatment at minimum 85 °C for 5 min completely removed the ADA interference. We then compared the analyte concentrations measured with and without heat pre-treatment of blood samples from toxicology studies performed for two different analytes in 60 cynomolgus monkeys and 29 minipigs, respectively. The overall difference in measured concentration of ADA-positive samples was significantly different from the overall difference in measured concentration of ADA-negative samples. For the cynomolgus monkey study samples, the ADA titer was determined, and the difference in measured concentration, when comparing heat pre-treatment to no heat pre-treatment, was significantly correlated to the ADA titer. Additionally, heat pre-treatment removed parallelism issues observed in a subset of study samples. Our data suggest that sample heat pre-treatment can abolish ADA interference in an LBA and could serve as a tool to assess the degree of ADA interference and the total drug concentration in a PK sample. Of note, before utilizing this strategy on a new analyte, it is necessary to assess whether heat pre-treatment negatively affects the detection of the analyte by the assay antibodies.

REGEN-COV® antibody cocktail bioanalytical strategy: comparison of LC-MRM-MS and immunoassay methods for drug quantification

Aim: In response to the COVID-19 pandemic, Regeneron developed the anti-SARS-CoV-2 monoclonal antibody cocktail, REGEN-COV^® (RONAPREVE^® outside the USA). Drug concentration data was important for determination of dose, so a two-part bioanalytical strategy was implemented to ensure the therapy was rapidly available for use. Results & methodology: Initially, a liquid chromatography-multiple reaction monitoring-mass spectrometry (LC-MRM-MS) assay, was used to analyze early-phase study samples. Subsequently, a validated electrochemiluminescence (ECL) immunoassay was implemented for high throughput sample analysis for all samples. A comparison of drug concentration data from the methods was performed which identified strong linear correlations and for Bland-Altman, small bias. In addition, pharmacokinetic data from both methods produced similar profiles and parameters. Discussion & conclusion: This novel bioanalytical strategy successfully supported swift development of a critical targeted therapy during the COVID-19 public health emergency.

Liquid chromatography-mass spectrometry method for the quantification of an anti-sclerostin monoclonal antibody in cynomolgus monkey serum

Liquid chromatography tandem mass spectrometry (LC-MS/MS) has gradually become a promising alternative to ligand binding assay for the bioanalysis of biotherapeutic molecules, due to its rapid method development and high accuracy. In this study, we established a new LC-MS/MS method for the determination of the anti-sclerostin monoclonal antibody (SHR-1222) in cynomolgus monkey serum, and compared it to a previous electrochemiluminescence method. The antibody was quantified by detecting the surrogate peptide obtained by trypsin digestion. The surrogate peptide was carefully selected by investigating its uniqueness, stability and MS response. The quantitative range of the proposed method was 2.00-500 μg/mL, and this verified method was successfully applied to the toxicokinetic assessment of SHR-1222 in cynomolgus monkey serum. It was found that the concentrations of SHR-1222 in cynomolgus monkeys displayed an excellent agreement between the LC-MS/MS and electrochemiluminescence methods (ratios of drug exposure, 0.8-1.0). Notably, two monkeys in the 60 mg/kg dose group had abnormal profiles with a low detection value of SHR-1222 in their individual sample. Combining the high-level anti-drug antibodies (ADAs) in these samples and the consistent quantitative results of the two methods, we found that the decreased concentration of SHR-1222 was due to the accelerated clearance mediated by ADAs rather than the interference of ADAs to the detection platform. Taken together, we successfully developed an accurate, efficient and cost-effective LC-MS/MS method for the quantification of SHR-1222 in serum samples, which could serve as a powerful tool to improve the preclinical development of antibody drugs.

LC-MS/MS analysis of lesional and normally looking psoriatic skin reveals significant changes in protein metabolism and RNA processing

Background

Plaque psoriasis is a chronic autoimmune disorder characterized by the development of red scaly plaques. To date psoriasis lesional skin transcriptome has been extensively studied, whereas only few proteomic studies of psoriatic skin are available.

Aim

The aim of this study was to compare protein expression patterns of lesional and normally looking skin of psoriasis patients with skin of the healthy volunteers, reveal differentially expressed proteins and identify changes in cell metabolism caused by the disease.

Methods

Skin samples of normally looking and lesional skin donated by psoriasis patients (n = 5) and samples of healthy skin donated by volunteers (n = 5) were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). After protein identification and data processing, the set of differentially expressed proteins was subjected to protein ontology analysis to characterize changes in biological processes, cell components and molecular functions in the patients’ skin compared to skin of the healthy volunteers. The expression of selected differentially expressed proteins was validated by ELISA and immunohistochemistry.

Results

The performed analysis identified 405 and 59 differentially expressed proteins in lesional and normally looking psoriatic skin compared to healthy control. In normally looking skin of the patients, we discovered decreased expression of KNG1, APOE, HRG, THBS1 and PLG. Presumably, these changes were needed to protect the epidermis from spontaneous activation of kallikrein-kinin system and delay the following development of inflammatory response. In lesional skin, we identified several large groups of proteins with coordinated expression. Mainly, these proteins were involved in different aspects of protein and RNA metabolism, namely ATP synthesis and consumption; intracellular trafficking of membrane-bound vesicles, pre-RNA processing, translation, chaperoning and degradation in proteasomes/immunoproteasomes.

Conclusion

Our findings explain the molecular basis of metabolic changes caused by disease in skin lesions, such as faster cell turnover and higher metabolic rate. They also indicate on downregulation of kallikrein-kinin system in normally looking skin of the patients that would be needed to delay exacerbation of the disease. Data are available via ProteomeXchange with identifier PXD021673.

The role of ligand-binding assay and LC-MS in the bioanalysis of complex protein and oligonucleotide therapeutics

Ligand-binding assay (LBA) and LC-MS have been the preferred bioanalytical techniques for the quantitation and biotransformation assessment of various therapeutic modalities. This review provides an overview of the applications of LBA, LC-MS/MS and LC-HRMS for the bioanalysis of complex protein therapeutics including antibody-drug conjugates, fusion proteins and PEGylated proteins as well as oligonucleotide therapeutics. The strengths and limitations of LBA and LC-MS, along with some guidelines on the choice of appropriate bioanalytical technique(s) for the bioanalysis of these therapeutic modalities are presented. With the discovery of novel and more complex therapeutic modalities, there is an increased need for the biopharmaceutical industry to develop a comprehensive bioanalytical strategy integrating both LBA and LC-MS.

Designing an enzyme-linked immunosorbent assay for detection of anti-penicillin antibodies levels in various species of animals in Khuzestan province, Iran

The penicillin allergy is being increasingly recognized as a significant public health problem. Immunological responses to penicillin and other beta-lactam antibiotics are classified as immediate and non-immediate responses. This research aimed to develop an enzyme-linked immunosorbent assay (ELISA) for the detection of the reactive antibody value against penicillin in various species of animals. The serum samples were collected from nine species (forty mature animals in each species) including horse, dog, goat, sheep, buffalo, cattle, donkey, chicken, and fish. The concentrations of total antibody and immunoglobulin M (IgM) against penicillin were detected using an in-house ELISA test. The total anti-penicillin antibodies concentration from high to low in animals was as chicken, horse, fish, donkey, dog, goat, sheep, buffalo, and cattle, respectively. In cattle and sheep, the level of anti-penicillin IgM (APM) was significantly higher than non-IgM antibodies (APNM). Moreover, levels of APNM were very low in chicken and fish serums; no difference was seen regarding these values in buffalo and goat. The other species had significantly lower APM than the APNM. The ani-penicillin antibody levels in the noted animals were successfully detected using the developed ELISA. Most of the species have anti-penicillin antibodies; however, they have reactive antibodies with differences in levels and isotypes.

A novel LC-MS/MS approach to the pharmacokinetic study of free and bound aflibercept simultaneously

To comprehensively evaluate the pharmacokinetic (PK) characteristics of aflibercept, we established a liquid chromatography with tandem mass spectrometry (LC-MS/MS) method to determine the concentration of vascular endothelial growth factor (VEGF)-A-bound aflibercept and free aflibercept. A specific sample preparation method of nano-surface and molecular-orientation limited (nSMOL) proteolysis was performed to extract both free and bound aflibercept from plasma. The tryptic peptides unique to aflibercept and VEGF-A were selected to quantify the amounts of total aflibercept and aflibercept-VEGF complex, respectively. The method was validated by evaluating its selectivity, linearity, precision, accuracy, extraction recovery, matrix effect, and stability. It was then successfully used to quantify total and bound aflibercept concentrations in cynomolgus monkey plasma, while indirectly obtaining the concentration of free aflibercept by subtraction. The PK results of this LC-MS/MS method are comparable to the traditional enzyme-linked immunosorbent assay (ELISA) results. It is thus a reliable and complementary method for the PK evaluation of aflibercept. Graphical abstract.

Determination of the concentration range for 267 proteins from 21 lots of commercial human plasma using highly multiplexed multiple reaction monitoring mass spectrometry

Multiple reaction monitoring (MRM) is a key tool for biomarker validation and the translation of potential biomarkers into the clinic.

From Synthesis to Characterization of Site-Selective PEGylated Proteins

Covalent attachment of therapeutic proteins to polyethylene glycol (PEG) is widely used for the improvement of its pharmacokinetic and pharmacological properties, as well as the reduction in reactogenicity and related side effects. This technique named PEGylation has been successfully employed in several approved drugs to treat various diseases, even cancer. Some methods have been developed to obtain PEGylated proteins, both in multiple protein sites or in a selected amino acid residue. This review focuses mainly on traditional and novel examples of chemical and enzymatic methods for site-selective PEGylation, emphasizing in N-terminal PEGylation, that make it possible to obtain products with a high degree of homogeneity and preserve bioactivity. In addition, the main assay methods that can be applied for the characterization of PEGylated molecules in complex biological samples are also summarized in this paper.

Six-step workflow for the quantification of therapeutic monoclonal antibodies in biological matrices with liquid chromatography mass spectrometry - A tutorial

The promising pipeline of therapeutic monoclonal antibodies (mAbs) demands robust bioanalytical methods with swift development times for pharmacokinetic studies. Over the past decades ligand binding assays were the methods of choice for absolute quantification. However, the production of the required anti-idiotypic antibodies and ligands limits high-throughput method development for sensitive, accurate, and reproducible quantification of therapeutic mAbs. In recent years, high-resolution liquid chromatography tandem mass-spectrometry (LC-MS) systems have enabled absolute quantification of therapeutic mAbs with short method development times. These systems have additional benefits, such as a large linear dynamic range, a high specificity and the option of multiplexing. Here, we briefly discuss the current strategies for the quantification of therapeutic mAbs in biological matrices using LC-MS analysis based on top-down and middle-down quantitative proteomics. Then, we present the widely used bottom-up method in a six-step workflow, which can be used as guidance for quantitative LC-MS/MS method development of mAbs. Finally, strengths and weaknesses of the bottom-up method, which currently provides the most benefits, are discussed in detail.

Glu-C, an alternative digestive enzyme for the quantitative LC–MS/MS analysis of an IgG-based antibody biotherapeutic

Aim: LC–MS/MS bottom-up quantitation of proteins has become increasingly popular with trypsin as the most commonly used protease. However, trypsin does not always yield suitable surrogate peptides. An alternative enzyme, Glu-C, was used to generate surrogate peptides for quantifying a bispecific IgG1 biotherapeutic antibody in preclinical matrices.  Materials and methods: IgG1 was quantified by pellet digestion using an Acquity UPLC coupled  with a Xevo TQ-S mass spectrometer.  Results: Two generic LC–MS/MS methods (heavy and light chain) were developed which afforded acceptable precision and accuracy, and an lower limit of quantitation of 1 μg/ml in three preclinical matrices. A small nonsignificant bias was observed when cynomolgus serum LC–MS/MS results were compared with electrochemiluminescent immunoassay data. Conclusion: Glu-C was successfully used as an alternative digestion enzyme for bottom-up quantitation of an IgG1 in matrices from multiple preclinical species, with good agreement with electrochemiluminescent immunoassay data.

Quantification of CSF cystatin C using liquid chromatography tandem mass spectrometry

BACKGROUND

Cystatin C (CST3), a ubiquitously expressed cysteine protease inhibitor, is implicated in several neurological diseases. Here, we have developed an accurate CST3 measurement system based on liquid chromatography tandem mass spectrometry (LC-MS/MS).

METHODS

LC-MS/MS based measurement for CSF CST3 was validated by determination of assay precision, accuracy and recovery. The values were compared with those measured by immunoassay. Glycosylation of CST3 in CSF was analyzed by Western blotting and lectin blotting.

RESULTS

Measuring standard CST3 by LC-MS/MS produced a linear standard curve that correlated with assigned values (r²=0.99). Both intra- and inter-assay variation was <10%. Although showed a correlation, the average CST3 concentration measured by LC-MS/MS was significantly higher than that of immunoassay. Western blotting showed the presence of a 25KDa species along with CST3 monomer (14KDa) in CSF. The volume of 25KDa species was decreased by deglycosylation. Lectin blotting revealed a 25KDa glycosylated protein in sialidase-treated CSF, which was decreased by deglycosylation. However, deglycosylation did not alter CST3 concentration measured by immunoassay.

CONCLUSIONS

Our results suggest that LC-MS/MS-based CST3 measurement is a robust method with higher detection ability. Such method could be useful for the diagnosis and monitoring of neurological diseases.

Novel strategy using tryptic peptide immunoaffinity-based LC–MS/MS to quantify denosumab in monkey serum

Aim: Denosumab is a recombinant fully human IgG2 that has a high affinity and specificity for human RANKL. Commercially available RANKL labeled with an Fc fragment cannot be used to establish an indirect ELISA. To characterize denosumab pharmacokinetic a robust and accuracy method should be developed urgently. Results: In this study, an immunoaffinity enrichment method coupled with LC–MS/MS was established. The LC–MS/MS method acquired a linear range from 0.1 to 30 μg/ml. The intra- and inter-run precision (CV%) was within 11.5 and 10.5%, respectively. More importantly, the LC–MS/MS pharmacokinetic data were consistent with ELISA. Conclusion: This approach accelerated the quantification, reduced the costs and provided an alternative in case of lacking the special antigen to denosumab or a RANKL-biotinylated reagent.

Reagent-free LC–MS/MS-based pharmacokinetic quantification of polyhistidine-tagged therapeutic proteins

Aim: Immobilized metal ion affinity chromatography is widely employed for purifying polyhistidine-tagged recombinant proteins from cell lysates. The technique can be applied for quantification of therapeutic proteins in biological matrices by LC–MS/MS. Results: A protein reagent-free workflow was developed for quantifying polyhistidine-tagged proteins by LC–MS/MS. The workflow includes target protein enrichment by immobilized metal ion affinity chromatography, on-bead trypsin digestion and quantification of signature peptides by LC–MS/MS. It was applied to quantify a 6×His-tagged protein in a mouse pharmacokinetic study with assay sensitivity of 10.0 ng/ml and linearity up to 10,000 ng/ml. Conclusion: The protein reagent-free workflow developed herein can overcome reagent limitation and serve as a viable approach for quantifying polyhistidine-tagged therapeutic proteins to support discovery pharmacokinetic and pharmacodynamic studies.

2016 White Paper on recent issues in bioanalysis: focus on biomarker assay validation (BAV): (Part 2 – Hybrid LBA/LCMS and input from regulatory agencies)

The 2016 10th Workshop on Recent Issues in Bioanalysis (10th WRIB) took place in Orlando, Florida with participation of close to 700 professionals from pharmaceutical/biopharmaceutical companies, biotechnology companies, contract research organizations, and regulatory agencies worldwide. WRIB was once again a 5-day, weeklong event – A Full Immersion Week of Bioanalysis including Biomarkers and Immunogenicity. As usual, it is specifically designed to facilitate sharing, reviewing, discussing and agreeing on approaches to address the most current issues of interest including both small and large molecules involving LCMS, hybrid LBA/LCMS, and LBA approaches, with the focus on biomarkers and immunogenicity. This 2016 White Paper encompasses recommendations emerging from the extensive discussions held during the workshop, and is aimed to provide the bioanalytical community with key information and practical solutions on topics and issues addressed, in an effort to enable advances in scientific excellence, improved quality and better regulatory compliance. This White Paper is published in 3 parts due to length. This part (Part 2) discusses the recommendations for Hybrid LBA/LCMS and regulatory inputs from major global health authorities. Parts 1 (small molecule bioanalysis using LCMS) and Part 3 (large molecule bioanalysis using LBA, biomarkers and immunogenicity) have been published in the Bioanalysis journal, issues 22 and 23, respectively.

Quantification of a bifunctional drug in the presence of an immune response: a ligand-binding assay specific for ‘active’ drug

Aim: During development of biologics, safety and efficacy assessments are often hampered by immune responses to the treatment. The raised antidrug antibodies (ADA) might interfere with the bioanalytical method and complicate result interpretation if non-fully characterized bioanalytical methods were applied. Methods: Here, we report an approach to characterize a ligand-binding assay (LBA) for the quantification of active drug exposure of a bifunctional therapeutic protein in the presence of antidrug antibodies, by correlating LBA results with those of a cell-based PK assay. Results: A clear correlation between both assays could be observed when monoclonal and polyclonal antibodies against the toxin moiety of the drug were used as ADA surrogates, and results were confirmed with human ADA-positive sera. Conclusion: The observed correlation between the LBA-based and cell-based PK assay indicated the suitability of the developed LBA for the determination of active drug exposure in the presence of an immune response.

Pharmacokinetic and pharmacodynamic considerations for the next generation protein therapeutics

Increasingly sophisticated protein engineering efforts have been undertaken lately to generate protein therapeutics with desired properties. This has resulted in the discovery of the next generation of protein therapeutics, which include: engineered antibodies, immunoconjugates, bi/multi-specific proteins, antibody mimetic novel scaffolds, and engineered ligands/receptors. These novel protein therapeutics possess unique physicochemical properties and act via a unique mechanism-of-action, which collectively makes their pharmacokinetics (PK) and pharmacodynamics (PD) different than other established biological molecules. Consequently, in order to support the discovery and development of these next generation molecules, it becomes important to understand the determinants controlling their PK/PD. This review discusses the determinants that a PK/PD scientist should consider during the design and development of next generation protein therapeutics. In addition, the role of systems PK/PD models in enabling rational development of the next generation protein therapeutics is emphasized.

2014 White Paper on recent issues in bioanalysis: a full immersion in bioanalysis (Part 2 - hybrid LBA/LCMS, ELN & regulatory agencies' input)

The 2014 8th Workshop on Recent Issues in Bioanalysis (8th WRIB), a 5-day full immersion in the evolving field of bioanalysis, took place in Universal City, California, USA. Close to 500 professionals from pharmaceutical and biopharmaceutical companies, contract research organizations and regulatory agencies worldwide convened to share, review, discuss and agree on approaches to address current issues of interest in bioanalysis. The topics covered included both small and large molecules, and involved LCMS, hybrid LBA/LCMS, LBA approaches and immunogenicity. From the prolific discussions held during the workshop, specific recommendations are presented in this 2014 White Paper. As with the previous years' editions, this paper acts as a practical tool to help the bioanalytical community continue advances in scientific excellence, improved quality and better regulatory compliance. Due to its length, the 2014 edition of this comprehensive White Paper has been divided into three parts for editorial reasons. This publication (Part 2) covers the recommendations for Hybrid LBA/LCMS, Electronic Laboratory Notebook and Regulatory Agencies' Input. Part 1 (Small molecules bioanalysis using LCMS) was published in the Bioanalysis issue 6(22) and Part 3 (Large molecules bioanalysis using LBA and Immunogenicity) will be published in the Bioanalysis issue 6(24).

Development and validation of an LC-MS/MS assay for the quantitation of a PEGylated anti-CD28 domain antibody in human serum: overcoming interference from antidrug antibodies and soluble target

AIM

To support drug development of a PEGylated anti-CD28 domain antibody, a sensitive and robust LC-MS/MS assay was developed for the first in-human multiple ascending dose study.

MATERIALS & METHODS

The procedure consists of a protein precipitation with acidified acetonitrile, followed by trypsin digestion of the supernatant. A surrogate peptide from the complementarity determining region was quantified with an LC-MS/MS assay using a stable isotope-labeled internal standard with flanking amino acids. An acid dissociation step was found to be essential to achieve full analyte recovery in the presence of antidrug antibodies and soluble target CD28.

RESULTS & CONCLUSION

The fully validated LC-MS/MS assay demonstrates good accuracy (% deviation ≤6.3) and precision (%CV ≤5.2) with an lower limit of quantitation of 10 ng/ml.

High-sensitivity quantitation of a Nanobody® in plasma by single-cartridge multidimensional SPE and ultra-performance LC–MS/MS

Background: A major challenge in protein quantitation based on enzymatic digestion of complex biological samples and subsequent LC–MS/MS analysis of a signature peptide is dealing with the high complexity of the matrix after digestion, which can reduce sensitivity considerably. Results: Using single cartridge multidimensional SPE, sufficient selectivity was introduced to allow quantitation in 50 µl of plasma down to 10.0 ng/ml (˜0.3 nM). An inhouse prepared 18O-labeled signature peptide was used as the internal standard. The procedure was validated for human and rabbit plasma. Conclusion: The developed SPE procedure allowed the sensitive and selective LC–MS/MS quantitation of the Nanobody® without the use of antibodies. When appropriate precautions are taken, the 18O-labeled peptide is a practical and economical alternative to custom synthesis.

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.

An exploratory universal LC–MS/MS assay for bioanalysis of hinge region-stabilized human IgG4 mAbs in clinical studies

Background: Due to the increasing number of monoclonal antibody (mAb) drug candidates entering clinical development, bioanalytical laboratories can benefit from generic liquid chromatography–tandem mass spectrometry (LC–MS/MS) assays capable of quantifying a variety of human mAb-based therapeutic drug candidates in plasma/serum samples from clinical studies. Results: We have developed and evaluated an exploratory LC–MS/MS assay capable of quantifying hinge region-stabilized IgG4 therapeutic mAb drugs and drug candidates in clinical samples. The exploratory assay is based upon a single ‘universal IgG4’ surrogate peptide. Conclusion: The novel exploratory LC–MS/MS assay reported herein, upon further refinement and full validation, is predicted to enable bioanalytical scientists to quantify all hinge region-stabilized human IgG4 therapeutic mAbs in human studies without having to develop a new assay for every new stabilized IgG4 mAb entering clinical development.

The integration of ligand binding and LC-MS-based assays into bioanalytical strategies for protein analysis

Both LBAs and LC–MS-based assays are reviewed and summarized for applications in quantitative protein analysis. A strategy for platform selection is proposed based on several factors that contribute to the complexities of bioanalysis of biologics. Protein types, multiple co-existing forms, post-translational modifications, and affinities to ADA, targets, and endogenous proteins need to be considered when selecting the most appropriate platform. Other factors, such as intended use of data, assay sensitivity, available reagents, and multiple analytes also impact on the choice of bioanalytical platform. At BMS, strategies for the seamless integration of both platforms are being implemented to provide not only PK/PD data of the molecules but also useful information of the amino acid structure and functional relationship of the proteins.

A white paper--consensus and recommendations of a global harmonization team on assessing the impact of immunogenicity on pharmacokinetic measurements

The Global Bioanalysis Consortium (GBC) set up an international team to explore the impact of immunogenicity on pharmacokinetic (PK) assessments. The intent of this paper is to define the field and propose best practices when developing PK assays for biotherapeutics. We focus on the impact of anti-drug antibodies (ADA) on the performance of PK assay leading to the impact on the reported drug concentration and exposure. The manuscript describes strategies to assess whether the observed change in the drug concentration is due to the ADA impact on drug clearance rates or is a consequence of ADA interference in the bioanalytical method applied to measure drug concentration. This paper provides the bioanalytical scientist guidance for developing ADA-tolerant PK methods. It is essential that the data generated in the PK, ADA, pharmacodynamic and efficacy/toxicity evaluations are viewed together. Therefore, the extent for the investigation of the PK sensitivity to the presence of ADA should be driven by the project needs and risk based.

Application and challenges in using LC–MS assays for absolute quantitative analysis of therapeutic proteins in drug discovery

As more protein therapeutics enter the drug-discovery pipeline, the traditional ligand-binding assay (LBA) faces additional challenges to meet the rapid and diverse bioanalytical needs in the early drug-discovery stage. The high specificity and sensitivity afforded by LC–MS, along with its rapid method development, is proving invaluable for the analysis of protein therapeutics in support of drug discovery. LC–MS not only serves as a quantitative tool to complement LBA in drug discovery, it also provides structural details at a molecular level, which are used to address issues that cannot be resolved using LBA alone. This review will describe the key benefits and applications, as well as the techniques and challenges for applying LC–MS to support protein quantification in drug discovery.

Development of a validated liquid chromatography tandem mass spectrometry assay for a PEGylated adnectin in cynomolgus monkey plasma using protein precipitation and trypsin digestion

A liquid chromatography tandem mass spectrometry (LC-MS/MS) method has been developed and validated for a PEGylated adnectin therapeutic protein in cynomolgus monkey plasma. The validated method was performed using protein precipitation coupled with trypsin digestion, followed by LC-MS/MS detection of a surrogate peptide generated from the PEGylated adnectin protein. A tryptic peptide generated from a PEGylated adnectin protein analog was used as the internal standard to standardize the digestion, extraction, and quantitation processes. The protein precipitation extraction of the protein from cynomolgus plasma was performed using an acidic 2-propanol organic solution. Following the extraction, the supernatant was removed and a 45min trypsin digestion was performed at 60°C on the supernatant layer. The linear dynamic range of the assay was 50.0-25,000ng/mL. Chromatographic separation was performed with an Acquity BEH C18 (1.7μm particle size, 2.1mm×50mm) column using gradient elution. The assay proved to have robust accuracy, precision, and stability for the representative surrogate peptide of the PEGylated adnectin protein being evaluated. The validated method was implemented as a high throughput assay for a PEGylated adnectin protein using a similar PEGylated adnectin therapeutic protein as the internal standard that can be used for future monkey toxicokinetic (TK) studies.

Theoretical considerations and practical approaches to address the effect of anti-drug antibody (ADA) on quantification of biotherapeutics in circulation

Continuous improvement in bioanalytical method development is desired in order to ensure the quality of the data and to better support pharmacokinetic (PK) and safety studies of biotherapeutics. One area that has been getting increasing attention recently is in the assessment of "free" and "total" analyte and the impact of the assay format on those assessments. To compliment these considerations, the authors provide a critical review of available literature and prospectively explore methods to mitigate the potential impact of anti-drug antibody on PK assay measurement. This challenge is of particular interest and importance since biotherapeutic drugs often elicit an immune response, and thus may have a direct impact on quantification of the drug for its PK and safety evaluations.

Identification of oxidative stress related proteins as biomarkers for lung cancer and chronic obstructive pulmonary disease in bronchoalveolar lavage

Lung cancer (LC) and chronic obstructive pulmonary disease (COPD) commonly coexist in smokers, and the presence of COPD increases the risk of developing LC. Cigarette smoke causes oxidative stress and an inflammatory response in lung cells, which in turn may be involved in COPD and lung cancer development. The aim of this study was to identify differential proteomic profiles related to oxidative stress response that were potentially involved in these two pathological entities. Protein content was assessed in the bronchoalveolar lavage (BAL) of 60 patients classified in four groups: COPD, COPD and LC, LC, and control (neither COPD nor LC). Proteins were separated into spots by two dimensional polyacrylamide gel electrophoresis (2D-PAGE) and examined by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF/TOF). A total of 16 oxidative stress regulatory proteins were differentially expressed in BAL samples from LC and/or COPD patients as compared with the control group. A distinct proteomic reactive oxygen species (ROS) protein signature emerged that characterized lung cancer and COPD. In conclusion, our findings highlight the role of the oxidative stress response proteins in the pathogenic pathways of both diseases, and provide new candidate biomarkers and predictive tools for LC and COPD diagnosis.