Recommendations for the Assessment and Management of Pre-existing Drug-Reactive Antibodies During Biotherapeutic Development

Biosimilars and immunogenicity: a matter of concern?

INTRODUCTION

Biosimilars have transformed treatment modalities across various medical fields such as oncology, rheumatology, and immunology. Despite their potential for reducing healthcare costs, concerns persist regarding their ability to induce an immune response, which could affect efficacy and safety. This review critically evaluates the current evidence on the immunogenicity of biosimilars and discusses the regulatory frameworks guiding their approval and monitoring.

AREAS COVERED

This review includes studies from databases like Scopus, PubMed, Web of Science, and ScienceDirect, published up to April 2024. It explores the 'totality of the evidence' approach used by regulatory bodies like the FDA and EMA, detailing analytical, preclinical, and clinical assessments that ensure biosimilars' similarity to their reference products in terms of structure, function, and clinical outcomes. The review also addresses the challenges and limitations in current research methodologies and the implications of immunogenicity on therapeutic efficacy and patient safety.

EXPERT OPINION

While substantial evidence confirms the safety and efficacy of biosimilars, the review emphasizes the need for continuous regulatory vigilance and advanced methodologies in post-marketing surveillance to capture long-term immunogenicity data effectively. It advocates for integrating cutting-edge analytical techniques and personalized medicine to better manage immunogenic risks associated with biological therapies.

Development of a validated novel bead extraction method for the detection of anti-PEG antibodies in human serum

AIMS

Polyethylene glycol (PEG) is used in many applications including drug development. Due to exposure to environmental products, there is a high prevalence of preexisting anti-PEG antibodies in the global human population. The presence of anti-PEG antibodies is a concern for potentially reducing the efficacy of therapeutics after administration and represents a risk of safety events after exposure to PEGylated drug products. We developed and validated a creative and sensitive method for the detection of anti-PEG antibodies in human serum to support clinical programs for PEGylated drugs.

METHODS

In this method, biotin-PEG streptavidin beads were used to extract anti-PEG antibodies from human serum for analysis in an anti-PEG ELISA assay. The same serum sample was analyzed in an anti-drug antibody assay.

RESULTS

The anti-PEG antibody assay was validated with a screening cut point of 1.41 normalized signal, confirmatory cut point of 32.2% inhibition, sensitivity of 7.81 ng/mL and sufficient reproducibility, selectivity, and drug tolerance in accordance with the FDA 2019 Immunogenicity guidance.

CONCLUSION

This method of removal of anti-PEG antibodies enables the use of a single sample to detect anti-drug and anti-PEG antibodies to support drug development programs.

Comparability of Elezanumab Safety, Tolerability, and Pharmacokinetics in Healthy Japanese, Chinese, and White Participants

Elezanumab is a fully human monoclonal antibody, which is directed against repulsive guidance molecule A. The safety, tolerability, pharmacokinetics (PK), and immunogenicity of elezanumab were assessed in 2 Phase 1 clinical studies. The objective of this study was to assess the PK, safety, tolerability, and immunogenicity following intravenous infusion of elezanumab in healthy adult Japanese, Han Chinese, and Caucasian participants as well as Western participants from the single-ascending-dose study. Elezanumab exposures were approximately 20% higher in Japanese and Han Chinese participants compared to White participants without controlling for body weight. After statistically controlling for body weight by including it as a covariate, the PK of elezanumab in White participants were comparable to those in Japanese and Han Chinese participants. The clinical implications of these exposure differences are yet to be determined. All adverse events were assessed by the investigator as having no reasonable possibility of being related to the study drugs and were mild in severity. No positive immunogenicity effect was observed that impacted elezanumab exposure or safety.

Paving the way for future gene therapies: A case study of scientific spillover from delandistrogene moxeparvovec

Gene therapies have potential to improve outcomes of severe diseases after only a single administration. Novel therapies are continually being developed using knowledge gained from prior successes, a concept known as scientific spillover. Gene therapy advancement requires extensive development at each stage: preclinical work to create and evaluate vehicles for delivery of the therapy, design of clinical development programs, and establishment of a large-scale manufacturing process. Pioneering gene therapies are generating spillover as investigators confront myriad issues specific to this treatment modality. These include frameworks for construct engineering, dose evaluation, patient selection, outcome assessment, and safety monitoring. Consequently, the benefits of these therapies extend beyond offering knowledge for treating any one disease to establishing new platforms and paradigms that will accelerate advancement of future gene therapies. This impact is even more profound in rare diseases, where developing therapies in isolation may not be possible. This review describes some instances of scientific spillover in healthcare, and specifically gene therapy, using delandistrogene moxeparvovec (SRP-9001), a gene therapy recently approved by the US Food and Drug Administration for the treatment of ambulatory pediatric patients aged 4-5 years with Duchenne muscular dystrophy with a confirmed mutation in the DMD gene, as a case study.

Neutralizing Antibody Validation Testing and Reporting Harmonization

Evolving immunogenicity assay performance expectations and a lack of harmonized neutralizing antibody validation testing and reporting tools have resulted in significant time spent by health authorities and sponsors on resolving filing queries. A team of experts within the American Association of Pharmaceutical Scientists' Therapeutic Product Immunogenicity Community across industry and the Food and Drug Administration addressed challenges unique to cell-based and non-cell-based neutralizing antibody assays. Harmonization of validation expectations and data reporting will facilitate filings to health authorities and are described in this manuscript. This team provides validation testing and reporting strategies and tools for the following assessments: (1) format selection; (2) cut point; (3) assay acceptance criteria; (4) control precision; (5) sensitivity including positive control selection and performance tracking; (6) negative control selection; (7) selectivity/specificity including matrix interference, hemolysis, lipemia, bilirubin, concomitant medications, and structurally similar analytes; (8) drug tolerance; (9) target tolerance; (10) sample stability; and (11) assay robustness.

Ravulizumab pharmacokinetics and pharmacodynamics in patients with generalized myasthenia gravis

INTRODUCTION

The terminal complement C5 inhibitor ravulizumab has a long elimination half-life, allowing maintenance dosing every 8 weeks. In the 26-week, double-blind, randomized, placebo-controlled period (RCP) of the CHAMPION MG study, ravulizumab provided rapid and sustained efficacy and was well tolerated in adults with anti-acetylcholine receptor antibody-positive (AChR Ab+) generalized myasthenia gravis (gMG). This analysis evaluated the pharmacokinetics (PK), pharmacodynamics (PD), and potential immunogenicity of ravulizumab in adults with AChR Ab+ gMG.

METHODS

Data were analyzed from 86 patients who received ravulizumab in the CHAMPION MG RCP. Ravulizumab dosing was weight-based: initial loading dose of 2400/2700/3000 mg on Day 1 and maintenance doses of 3000/3300/3600 mg on Day 15 and then every 8 weeks. PK parameters were estimated from serum ravulizumab concentrations determined pre- and post-dose; PD effects of ravulizumab on serum free C5 concentrations were measured; and immunogenicity was assessed using anti-drug antibody and neutralizing-antibody assays.

RESULTS

Target serum ravulizumab concentrations (> 175 µg/mL) were achieved immediately after the first ravulizumab dose (within 30 min of infusion completion) and maintained throughout the 26-week treatment period irrespective of patient body weight. Following the final maintenance dose, mean Cmax was 1548 µg/mL and Ctrough 587 µg/mL; no meaningful differences were noted among body-weight categories. Inhibition of serum free C5 was immediate, complete (< 0.5 μg/mL), and sustained throughout treatment in all patients. No treatment-emergent anti-drug antibodies were observed.

CONCLUSIONS

PK/PD evidence supports the use of ravulizumab every 8 weeks for immediate, complete, and sustained inhibition of terminal complement C5 in adults with AChR Ab+ gMG.

TRIAL REGISTRATION

ClinicalTrials.gov ID: NCT03920293 (April 18, 2019).

Anti-drug Antibody Sample Testing and Reporting Harmonization

A clear scientific and operational need exists for harmonized bioanalytical immunogenicity study reporting to facilitate communication of immunogenicity findings and expedient review by industry and health authorities. To address these key bioanalytical reporting gaps and provide a report structure for documenting immunogenicity results, this cross-industry group was formed to establish harmonized recommendations and a develop a submission template to facilitate agency filings. Provided here are recommendations for reporting clinical anti-drug antibody (ADA) assay results using ligand-binding assay technologies. This publication describes the essential bioanalytical report (BAR) elements such as the method, critical reagents and equipment, study samples, results, and data analysis, and provides a template for a suggested structure for the ADA BAR. This publication focuses on the content and presentation of the bioanalytical ADA sample analysis report. The interpretation of immunogenicity data, including the evaluation of the impact of ADA on safety, exposure, and efficacy, is out of scope of this publication.

Interference in a Neutralizing Antibody Assay for Odronextamab, a CD20xCD3 Bispecific mAb, from Prior Rituximab Therapy and Possible Mitigation Strategy

A cell-based assay was developed to detect neutralizing anti-drug antibodies (NAbs) against odronextamab, a CD20xCD3 bispecific monoclonal antibody (mAb) under investigation for treatment of CD20+ B cell malignancies. In this assay, odronextamab bridges between two cell types, CD20-expressing HEK293 cells and CD3-expressing Jurkat T cells that generate a luciferase signal upon CD3 clustering. Patient samples containing NAbs directed to either arm of the bispecific drug block the odronextamab bridge formation between the cell lines thus preventing the generation of the luciferase signal. We determined that other anti-CD20 therapeutics also block bridge formation, resulting in false-positive results. In patient samples from odronextamab clinical trials, approximately 30% of baseline samples had a strong false-positive NAb signal that correlated with the presence of prior rituximab (anti-CD20) therapy. We determined that rituximab interference can be minimized by the addition of anti-rituximab antibodies in the NAb assay. Understanding and mitigating the impact of prior biologic exposure is increasingly important for implementing a successful bioanalytical strategy to support clinical drug development, especially in the immuno-oncology field.

Graphical Abstract

Odronextamab neutralizing antibody assay, interference, and mitigation. A Design of the odronextamab neutralizing antibody (NAb) assay where anti-CD20xCD3 drug bridges between CD20-expressing HEK293 cells and Jurkat T cells expressing an NFAT response element and luciferase reporter. True NAb prevents odronextamab from bridging between target and effector cells, thus preventing the expression of luciferase. B Interference with odronextamab from other anti-CD20 therapeutic antibodies (e.g., rituximab) from prior disease treatment generates a false-positive NAb result. Assay interference can be mitigated with an anti-idiotypic antibody against the interfering therapy.

A randomized, placebo-controlled clinical trial evaluating olipudase alfa enzyme replacement therapy for chronic acid sphingomyelinase deficiency (ASMD) in adults: One-year results

PURPOSE

This trial aimed to assess the efficacy and safety of olipudase alfa enzyme replacement therapy for non-central nervous system manifestations of acid sphingomyelinase deficiency (ASMD) in adults.

METHODS

A phase 2/3, 52 week, international, double-blind, placebo-controlled trial (ASCEND; NCT02004691/EudraCT 2015-000371-26) enrolled 36 adults with ASMD randomized 1:1 to receive olipudase alfa or placebo intravenously every 2 weeks with intrapatient dose escalation to 3 mg/kg. Primary efficacy endpoints were percent change from baseline to week 52 in percent predicted diffusing capacity of the lung for carbon monoxide and spleen volume (combined with splenomegaly-related score in the United States). Other outcomes included liver volume/function/sphingomyelin content, pulmonary imaging/function, platelet levels, lipid profiles, and pharmacodynamics.

RESULTS

Least square mean percent change from baseline to week 52 favored olipudase alfa over placebo for percent predicted diffusing capacity of the lung for carbon monoxide (22% vs 3.0% increases, P = .0004), spleen volume (39% decrease vs 0.5% increase, P < .0001), and liver volume (28% vs 1.5% decreases, P < .0001). Splenomegaly-related score decreased in both groups (P = .64). Other clinical outcomes improved in the olipudase alfa group compared with the placebo group. There were no treatment-related serious adverse events or adverse event-related discontinuations. Most adverse events were mild.

CONCLUSION

Olipudase alfa was well tolerated and associated with significant and comprehensive improvements in disease pathology and clinically relevant endpoints compared with placebo in adults with ASMD.

Immunogenicity assessment of bispecific antibody-based immunotherapy in oncology

With increasing numbers of bispecific antibodies (BsAbs) and multispecific products entering the clinic, recent data highlight immunogenicity as an emerging challenge in the development of such novel biologics. This review focuses on the immunogenicity risk assessment (IgRA) of BsAb-based immunotherapies for cancer, highlighting several risk factors that need to be considered. These include the novel scaffolds consisting of bioengineered sequences, the potentially synergistic immunomodulating mechanisms of action (MOAs) from different domains of the BsAb, as well as several other product-related and patient-related factors. In addition, the clinical relevance of anti-drug antibodies (ADAs) against selected BsAbs developed as anticancer agents is reviewed and the advances in our knowledge of tools and strategies for immunogenicity prediction, monitoring, and mitigation are discussed. It is critical to implement a drug-specific IgRA during the early development stage to guide ADA monitoring and risk management strategies. This IgRA may include a combination of several assessment tools to identify drug-specific risks as well as a proactive risk mitigation approach for candidate or format selection during the preclinical stage. The IgRA is an on-going process throughout clinical development. IgRA during the clinical stage may bridge the gap between preclinical immunogenicity prediction and clinical immunogenicity, and retrospectively guide optimization efforts for next-generation BsAbs. This iterative process throughout development may improve the reliability of the IgRA and enable the implementation of effective risk mitigation strategies, laying the foundation for improved clinical success.

Anti-drug Antibody Validation Testing and Reporting Harmonization

Evolving immunogenicity assay performance expectations and a lack of harmonized anti-drug antibody validation testing and reporting tools have resulted in significant time spent by health authorities and sponsors on resolving filing queries. Following debate at the American Association of Pharmaceutical Sciences National Biotechnology Conference, a group was formed to address these gaps. Over the last 3 years, 44 members from 29 organizations (including 5 members from Europe and 10 members from FDA) discussed gaps in understanding immunogenicity assay requirements and have developed harmonization tools for use by industry scientists to facilitate filings to health authorities. Herein, this team provides testing and reporting strategies and tools for the following assessments: (1) pre-study validation cut point; (2) in-study cut points, including procedures for applying cut points to mixed populations; (3) system suitability control criteria for in-study plate acceptance; (4) assay sensitivity, including the selection of an appropriate low positive control; (5) specificity, including drug and target tolerance; (6) sample stability that reflects sample storage and handling conditions; (7) assay selectivity to matrix components, including hemolytic, lipemic, and disease state matrices; (8) domain specificity for multi-domain therapeutics; (9) and minimum required dilution and extraction-based sample processing for titer reporting.

Safety, Tolerability, Pharmacokinetics, and Immunogenicity of a Monoclonal Antibody (SCTA01) Targeting SARS-CoV-2 in Healthy Adults: a Randomized, Double-Blind, Placebo-Controlled, Phase I Study

SCTA01 is a novel monoclonal antibody with promising prophylactic and therapeutic potential for COVID-19. This study aimed to evaluate the safety, tolerability, pharmacokinetics (PK) and immunogenicity of SCTA01 in healthy adults. This was a randomized, double-blind, placebo-controlled, dose escalation phase I clinical trial. Healthy adults were randomly assigned to cohort 1 (n = 5; 3:2), cohort 2 (n = 8; 6:2), cohort 3, or cohort 4 (both n = 10; 8:2) to receive SCTA01 (5, 15, 30, and 50 mg/kg, respectively) versus placebo. All participants were followed up for clinical, laboratory, PK, and immunogenicity assessments for 84 days. The primary outcomes were the dose-limiting toxicity (DLT) and maximal tolerable dose (MTD), and the secondary outcomes included PK parameters, immunogenicity, and adverse events (AE). Of the 33 participants, 18 experienced treatment-related AEs; the frequency was 52.0% (13/25) in participants receiving SCTA01 and 62.5% (5/8) in those receiving placebo. All AEs were mild. There was no serious AE or death. No DLT was reported, and the MTD of SCTA01 was not reached. SCTA01 with a dose range of 5 to 50 mg/kg had nearly linear dose-proportional increases in Cmax and AUC parameters. An antidrug antibody response was detected in four (16.0%) participants receiving SCTA01, with low titers, between the baseline and day 28, but all became negative later. In conclusion, SCTA01 up to 50 mg/kg was safe and well-tolerated in healthy participants. Its PK parameters were nearly linear dose-proportional. (This study has been registered at ClinicalTrials.gov under identifier NCT04483375.).

One-year results of a clinical trial of olipudase alfa enzyme replacement therapy in pediatric patients with acid sphingomyelinase deficiency

PURPOSE

To assess olipudase alfa enzyme replacement therapy for non-central nervous system manifestations of acid sphingomyelinase deficiency (ASMD) in children.

METHODS

This phase 1/2, international, multicenter, open-label trial (ASCEND-Peds/NCT02292654) administered intravenous olipudase alfa every 2 weeks with intrapatient dose escalation to 3 mg/kg. Primary outcome was safety through week 64. Secondary outcomes included pharmacokinetics, spleen and liver volumes, lung diffusing capacity (DLCO), lipid profiles, and height through week 52.

RESULTS

Twenty patients were enrolled: four adolescents (12-17 years), nine children (6-11 years), and seven infants/early child (1-5 years). Most adverse events were mild or moderate, including infusion-associated reactions (primarily urticaria, pyrexia, and/or vomiting) in 11 patients. Three patients had serious treatment-related events: one with transient asymptomatic alanine aminotransferase increases, another with urticaria and rash (antidrug antibody positive [ADA+]), and a third with an anaphylactic reaction (ADA+) who underwent desensitization and reached the 3 mg/kg maintenance dose. Mean splenomegaly and hepatomegaly improved by >40% (p < 0.0001). Mean % predicted DLCO improved by 32.9% (p = 0.0053) in patients able to perform the test. Lipid profiles and elevated liver transaminase levels normalized. Mean height Z-scores improved by 0.56 (p < 0.0001).

CONCLUSION

In this study in children with chronic ASMD, olipudase alfa was generally well-tolerated with significant, comprehensive improvements in disease pathology across a range of clinically relevant endpoints.

Development of a Highly Specific Anti-drug Antibody Assay in Support of a Nanoparticle-based Therapeutic

PEGylated biotherapeutics can elicit anti-PEG (polyethylene glycol) immune responses in patients treated with this category of drugs. While anti-PEG antibody assays for this class of biotherapeutics have become a common element of the clinical immunogenicity testing strategy, the overall antibody incidence induced by the nanoparticle (NP) delivery system (such as ACCURINS®) has not been fully studied to date. To support the immunogenicity assessment of one of Pfizer's NP-based therapeutics, consisting of gedatolisib (GEDA) encapsulated in ACCURINS® (GEDA-NP), we developed an anti-GEDA-NP antibody (ADA) assay on the MSD platform for the detection of GEDA-NP induced ADA in human serum. The focus of our strategy was on developing a clinically relevant ADA assay and systematically addressing assay interference through rigorous assay optimization. Our efforts led to a fit-for-purpose assay for the detection of anti-GEDA-NP ADA in serum samples obtained from breast cancer patients. Results from method qualification indicated robust assay performance, as highlighted by inter and intra-assay precision within 25% CV for all controls, and reproducible response profiles across multiple runs during the assessment of assay cut points with breast cancer samples. The assay sensitivity was between 4.3 ng/mL and 123 ng/mL for surrogate positive controls of IgG and IgM isotypes, respectively. Additionally, assay interference from nonspecific matrix proteins and circulating drug was addressed, which ensured accurate assessment of ADA incidence that can be attributed to GEDA-NP.

Analysis of regulatory guidance on antidrug antibody testing for therapeutic protein products

Therapeutic proteins have the potential to induce unwanted immune responses. The potential impact of immunogenicity on pharmacokinetics, pharmacodynamics, safety and efficacy are well established. Here, we analyze key aspects of current US FDA and EMA guidelines on the development and validation of antidrug antibody assays. Although FDA and EMA guidance documents are in harmony on most points, EMA allows greater leeway for scientific judgement, while FDA recommends specific approaches that may not be appropriate in some situations. Many white papers suggest approaches different from the guidance documents, however, these can conflict with each other and are themselves only scientifically valid in certain situations. Here, we indicate when alternatives to guidance may be needed and what those approaches might be.

Anti-drug Antibody Assay Validation: Improved Reporting of the Assay Selectivity via Simpler Positive Control Recovery Data Analysis

Anti-drug antibody (ADA) assay selectivity is evaluated during assay validation to assess the potential for individual matrices to interfere with detection of ADA. While current EMA and FDA guideline documents suggest comparative analysis with and without matrix, they do not provide specific recommendations on the acceptance criteria such as an acceptable percent positive control (PC) recovery range or positive rate. Industry has adopted an approach where recovery of PC spiked sample is expected to fall within ± 20% (80 to 120%) vs. that for the PC material spiked in negative control matrix or assay buffer. Here, it is proposed that ADA assay selectivity evaluated using a qualitative assessment of PC recovery vs. a PK-like quantitative method may be more appropriate. The PC recovery test should focus on the reliability of the method to detect the low PC level in individual samples and avoid false-negative ADA reporting. Therefore, it is proposed that assessment of high PC level as well as the assessment of quantitative percent recovery (within ± 20%) should not be included in the test. The recovery test may be viewed as acceptable should a pre-selected number of individual samples (for example at least 8 or 9 out of 10) prepared at the low PC concentration of the assay score as ADA positive.

Randomized phase I clinical trial of anti-α-synuclein antibody BIIB054

BACKGROUND

Pathological and genetic evidence implicates toxic effects of aggregated α-synuclein in the pathophysiology of neuronal dysfunction and degeneration in Parkinson's disease. Immunotherapy targeting aggregated α-synuclein is a promising strategy for delaying disease progression.

OBJECTIVE

This study (NCT02459886) evaluated the safety, tolerability, and pharmacokinetics of BIIB054, a human-derived monoclonal antibody that preferentially binds to aggregated α-synuclein, in healthy volunteers and participants with Parkinson's disease.

METHODS

A total of 48 healthy volunteers (age 40-65, 19 women) and 18 Parkinson's disease participants (age 47-75, 5 women, Hoehn and Yahr stage ≤2.5) were in the study. Volunteers were enrolled into 6 single-dose cohorts of BIIB054 (range 1-135 mg/kg) or placebo, administered intravenously; Parkinson's disease participants received a single dose of BIIB054 (15 or 45 mg/kg) or placebo. All participants were evaluated for 16 weeks with clinical, neuroimaging, electrocardiogram, and laboratory assessments. Serum and cerebrospinal fluid BIIB054 concentrations were measured. BIIB054/α-synuclein complexes were measured in plasma.

RESULTS

Most adverse events were mild and assessed by investigators as unrelated to the study drug. Pharmacokinetic parameters for volunteers and the Parkinson's disease participants were similar. BIIB054 serum exposure and maximum concentrations were dose proportional during the dose range studied. In volunteers and the Parkinson's disease participants, the serum half-life of BIIB054 was 28 to 35 days; the cerebrospinal fluid-to-serum ratio ranged from 0.13% to 0.56%. The presence of BIIB054/α-synuclein complexes in plasma was confirmed; all Parkinson's disease participants showed almost complete saturation of the BIIB054/α-synuclein complex formation.

CONCLUSIONS

BIIB054 has favorable safety, tolerability, and pharmacokinetic profiles in volunteers and Parkinson's disease participants, supporting further clinical development. © 2019 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.

2018 White Paper on Recent Issues in Bioanalysis: focus on flow cytometry, gene therapy, cut points and key clarifications on BAV (Part 3 - LBA/cell-based assays: immunogenicity, biomarkers and PK assays)

The 2018 12^th Workshop on Recent Issues in Bioanalysis took place in Philadelphia, PA, USA on April 9-13, 2018 with an attendance of over 900 representatives from pharmaceutical/biopharmaceutical companies, biotechnology companies, contract research organizations and regulatory agencies worldwide. WRIB was once again a 5-day full immersion in bioanalysis, biomarkers and immunogenicity. As usual, it was specifically designed to facilitate sharing, reviewing, discussing and agreeing on approaches to address the most current issues of interest including both small- and large-molecule bioanalysis involving LCMS, hybrid LBA/LCMS and LBA/cell-based assays approaches. This 2018 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. Due to its length, the 2018 edition of this comprehensive White Paper has been divided into three parts for editorial reasons. This publication (Part 3) covers the recommendations for large molecule bioanalysis, biomarkers and immunogenicity using LBA and cell-based assays. Part 1 (LCMS for small molecules, peptides, oligonucleotides and small molecule biomarkers) and Part 2 (hybrid LBA/LCMS for biotherapeutics and regulatory agencies' inputs) are published in volume 10 of Bioanalysis, issues 22 and 23 (2018), respectively.