2020 White Paper on Recent Issues in Bioanalysis: Vaccine Assay Validation, qPCR Assay Validation, QC for CAR-T Flow Cytometry, NAb Assay Harmonization and ELISpot Validation (Part 3 - Recommendations on Immunogenicity Assay Strategies, NAb Assays, Biosimilars and FDA/EMA Immunogenicity Guidance/Guideline, Gene & Cell Therapy and Vaccine Assays)

The 14^th edition of the Workshop on Recent Issues in Bioanalysis (14^th WRIB) was held virtually on June 15-29, 2020 with an attendance of over 1000 representatives from pharmaceutical/biopharmaceutical companies, biotechnology companies, contract research organizations, and regulatory agencies worldwide. The 14^th WRIB included three Main Workshops, seven Specialized Workshops that together spanned 11 days in order to allow exhaustive and thorough coverage of all major issues in bioanalysis, biomarkers, immunogenicity, gene therapy and vaccine. Moreover, a comprehensive vaccine assays track; an enhanced cytometry track and updated Industry/Regulators consensus on BMV of biotherapeutics by LCMS were special features in 2020. As in previous years, this year's WRIB continued to gather a wide diversity of international industry opinion leaders and regulatory authority experts working on both small and large molecules to facilitate sharing and discussions focused on improving quality, increasing regulatory compliance and achieving scientific excellence on bioanalytical issues. This 2020 White Paper encompasses recommendations emerging from the extensive discussions held during the workshop and is aimed to provide the Global 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 2020 edition of this comprehensive White Paper has been divided into three parts for editorial reasons. This publication (Part 3) covers the recommendations on Vaccine, Gene/Cell Therapy, NAb Harmonization and Immunogenicity). Part 1 (Innovation in Small Molecules, Hybrid LBA/LCMS & Regulated Bioanalysis), Part 2A (BAV, PK LBA, Flow Cytometry Validation and Cytometry Innovation) and Part 2B (Regulatory Input) are published in volume 13 of Bioanalysis, issues 4 and 5 (2020), respectively.

The enhanced immunopharmacology of VIB4920, a novel Tn3 fusion protein and CD40L antagonist, and assessment of its safety profile in cynomolgus monkeys

BACKGROUND AND PURPOSE

Inhibition of the T- and B-cell interaction through the CD40/CD40 ligand (L) axis is a favourable approach for inflammatory disease treatment. Clinical studies of anti-CD40L molecules in autoimmune diseases have met challenges because of thromboembolic events and adverse haemostasis. VIB4920 (formerly MEDI4920) is a novel CD40L antagonist and Tn3 fusion protein designed to prevent adverse haemostasis and immunopharmacology. We evaluated the pharmacokinetics, activity and toxicity of VIB4920 in monkeys.

EXPERIMENTAL APPROACH

Cynomolgus monkeys received i.v. or s.c. 5-300 mg·kg^-1 VIB4920 or vehicle, once weekly for 1 month (Studies 1 and 2) or 28 weeks (Study 3). VIB4920 exposure and bioavailability were determined using pharmacokinetic analyses, and immune cell population changes via flow cytometry. Pharmacological activity was evaluated by measuring the animals' capacity to elicit an immune response to keyhole limpet haemocyanin (KLH) and tetanus toxoid (TT).

KEY RESULTS

VIB4920 demonstrated linear pharmacokinetics at multiple doses. Lymphocyte, monocyte, cytotoxic T-cell and NK cell counts were not significantly different between treatment groups. B-cell counts reduced dose-dependently and the T-cell dependent antibody response to KLH was suppressed by VIB4920 dose-dependently. The recall response to TT was similar across treatment groups. No thromboembolic events or symptoms of immune system dysfunctionality were observed.

CONCLUSIONS AND IMPLICATIONS

VIB4920 demonstrated an acceptable safety profile in monkeys. VIB4920 showed favourable pharmacokinetics, dose-dependent inhibition of a neoantigen-specific immune response and no adverse effects on immune function following long-term use. Our data support the use of VIB4920 in clinical trials.

Generation, Characterization, and Quantitative Bioanalysis of Drug/Anti-drug Antibody Immune Complexes to Facilitate Dedicated In Vivo Studies

PURPOSE

Immunogenicity against biotherapeutics can lead to the formation of drug/anti-drug-antibody (ADA) immune complexes (ICs) with potential impact on safety and drug pharmacokinetics (PK). This work aimed to generate defined drug/ADA ICs, characterized by quantitative (bio) analytical methods for dedicated determination of IC sizes and IC profile changes in serum to facilitate future in vivo studies.

METHODS

Defined ICs were generated and extensively characterized with chromatographic, biophysical and imaging methods. Quantification of drug fully complexed with ADAs (drug in ICs) was performed with an acid dissociation ELISA. Sequential coupling of SEC and ELISA enabled the reconstruction of IC patterns and thus analysis of IC species in serum.

RESULTS

Characterization of generated ICs identified cyclic dimers, tetramers, hexamers, and larger ICs of drug and ADA as main IC species. The developed acid dissociation ELISA enabled a total quantification of drug fully complexed with ADAs. Multiplexing of SEC and ELISA allowed unbiased reconstruction of IC oligomeric states in serum.

CONCLUSIONS

The developed in vitro IC model system has been properly characterized by biophysical and bioanalytical methods. The specificity of the developed methods enable discrimination between different oligomeric states of ICs and can be bench marking for future in vivo studies with ICs.

Infusions of Large Synthetic HDL Containing Trimeric apoA-I Stabilize Atherosclerotic Plaques in Hypercholesterolemic Rabbits

BACKGROUND

Among strategies to reduce the remaining risk of cardiovascular disease, interest has focused on using infusions of synthetic high-density lipoprotein (sHDL).

METHODS

New Zealand rabbits underwent a perivascular injury at both carotids and were randomly allocated into 2 protocols: (1) a single-dose study, where rabbits were treated with a single infusion of sHDL containing a trimeric form of human apoA-I (TN-sHDL, 200 mg/kg) or with Placebo; (2) a multiple-dose study, where 4 groups of rabbits were treated 5 times with Placebo or TN-sHDL at different doses (8, 40, 100 mg/kg). Plaque changes were analysed in vivo by intravascular ultrasound. Blood was drawn from rabbits for biochemical analyses and cholesterol efflux capacity evaluation.

RESULTS

In both protocols, atheroma volume in the Placebo groups increased between the first and the second intravascular ultrasound evaluation. A stabilization or a slight regression was instead observed vs baseline in the TN-sHDL-treated groups (P < 0.005 vs Placebo after infusion). TN-sHDL treatment caused a sharp rise of plasma-free cholesterol levels and a significant increase of total cholesterol efflux capacity. Histologic analysis of carotid plaques showed a reduced macrophage accumulation in TN-sHDL-treated rabbits compared with Placebo (P < 0.05).

CONCLUSIONS

Our results demonstrate that acute and subacute treatments with TN-sHDL are effective in stabilizing atherosclerotic plaques in a rabbit model. This effect appears to be related to a reduced intraplaque accumulation of inflammatory cells. Besides recent failures in proving its efficacy, sHDL treatment remains a fascinating therapeutic option for the reduction of cardiovascular risk.

Effects of fat-to-sugar ratio in excess dietary energy on lipid abnormalities: a 7-month prospective feeding study in adult cynomolgus monkeys

BACKGROUND

Excess energy intake contributes to metabolic disorders. However, the relationship between excess sugar and fat in their contributions to metabolic abnormalities remains to be further elucidated. Here we conducted a prospective feeding experiment to evaluate effects of dietary fat-to-sugar ratio on diet-induced metabolic abnormalities in adult cynomolgus monkeys.

METHODS

Four groups of adult cynomolgus monkeys were fed regular chow plus emulsion with combinations of high sugar (HS) or low sugar (HS) and low fat (LF) or high fat (HF) for 7 months. Plasma levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglyceride (TG) and blood glucose were measured for all the four groups of animals during the experiment.

RESULTS

Plasma levels of TC and LDL-C gradually increased in all 4 diets groups, with the highest increase found in the LSHF group compared to the other three groups (P = 0.0018 and P = 0.0005 respectively). HF induced increased fasting glucose (P = 0.0077) and HS induced higher TG (P = 0.0227) respectively. Intriguingly, HSHF led to dramatically smaller magnitude of increase in LDL-C and TC levels compared to LSHF, while such difference was absent between the LSLF and LSHF groups. Our findings thus indicate interactive effects of HS and HF on TC and LDL-C. In addition, HF exhibited stronger effects on lipid abnormalities than HS.

CONCLUSIONS

In the current study, our prospective feeding experiment in adult cynomolgus monkeys revealed effects of different fat-to-sugar ratios on diet-induced metabolic abnormalities. Furthermore, our findings suggest that not only excess dietary energy but also the balance of dietary fat-to-sugar ratio matters in diet-induced lipid abnormalities.

Intravenous toxicity and toxicokinetics of an HDL mimetic, Fx-5A peptide complex, in cynomolgus monkeys

Fx-5A peptide complex (Fx-5A), a High Density Lipoproteins (HDL) mimetic, has been shown to reduce atherosclerosis. The safety and toxicokinetics of Fx-5A administered IV by 30 min infusion at 8, 25 or 75 mg/kg body weight or vehicle, once every other day for 27 days, were assessed in cynomolgus monkeys. The Fx-5A was well tolerated at all doses. At the highest dose, there were statistically significant effects on hematology and clinical chemistry parameters that were considered non-adverse. Dose-dependent recoverable non-adverse erythrocytes morphological changes (acanthocytes, echinocytes, spherocytes, microcytes, and/or schistocytes) were observed. Fx-5A was not hemolytic in in-vitro fresh NHP or human blood assay. There were no Fx-5A-related statistically significant changes for any cardiovascular function, ECG or respiratory parameters, when compared to control. In addition, there were no Fx-5A-related effects on organ weights, macroscopic or microscopic endpoints. Finally, Fx-5A exhibited sporadic non-appreciable detection of anti-Fx-5A antibodies and a dose-dependent linear toxicokinetics with T1/2 value ranges from 2.7 to 6.2 h. In conclusion, the No Observed Adverse Effect Level was considered to be 75 mg/kg/day with associated exposures average Cmax and AUC0-last of 453 μg/mL and 2232 h μg/mL, respectively, on Day 27.

Biomarkers for nonclinical infusion reactions in marketed biotherapeutics and considerations for study design

The observation of an infusion reaction (IR) in a nonclinical study can cause concern among investigators and regulators in the development of biotherapeutics. Biomarkers can be informative to determine whether the reactions are immune-mediated or test-article related and if there is a potential risk to human subjects. IRs encompass a broad range of adverse events with a variety of triggers; the focus of this paper is IRs due to cytokine release syndrome or immune complex formation and the associated biomarkers. Such reactions generally do not preclude clinical development or marketing approval, because it is widely accepted that immune-mediated reactions in nonclinical species are not predictive of human outcomes. Several US approved products (from 2004 to 2016) have documented IRs in nonclinical species. This review article discusses recent examples, the biomarkers evaluated, and implications for study design and conduct.

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Approved biotherapeutics have produced nonclinical infusion reactions (IRs).

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Nonclinical IRs after a first dose are associated with cytokine release.

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Nonclinical IRs after several doses are associated with ADA.

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ADA-mediated IRs may result in immune complex tissue deposition.

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Diagnosing nonclinical IRs requires a weight-of-evidence approach using biomarkers.