Antibody-mediated side effects of recombinant proteins

Escherichia coli and Pichia pastoris: microbial cell-factory platform for -full-length IgG production

Owing to the unmet demand, the pharmaceutical industry is investigating an alternative host to mammalian cells to produce antibodies for a variety of therapeutic and research applications. Regardless of some disadvantages, Escherichia coli and Pichia pastoris are the preferred microbial hosts for antibody production. Despite the fact that the production of full-length antibodies has been successfully demonstrated in E. coli, which has mostly been used to produce antibody fragments, such as: antigen-binding fragments (Fab), single-chain fragment variable (scFv), and nanobodies. In contrast, Pichia, a eukaryotic microbial host, is mostly used to produce glycosylated full-length antibodies, though hypermannosylated glycan is a major challenge. Advanced strategies, such as the introduction of human-like glycosylation in endotoxin-edited E. coli and cell-free system-based glycosylation, are making progress in creating human-like glycosylation profiles of antibodies in these microbes. This review begins by explaining the structural and functional requirements of antibodies and continues by describing and analyzing the potential of E. coli and P. pastoris as hosts for providing a favorable environment to create a fully functional antibody. In addition, authors compare these microbes on certain features and predict their future in antibody production. Briefly, this review analyzes, compares, and highlights E. coli and P. pastoris as potential hosts for antibody production.

Subvisible Particles in Solutions of Remicade in Intravenous Saline Activate Immune System Pathways in In Vitro Human Cell Systems

Among patients that receive Remicade® therapy, more than 20% have adverse infusion related reactions and approximately 50% have immunogenic responses.^1-3 Upon characterization of initial Remicade®-IV solution we observed a high concentration of subvisible particles that could inadvertently be delivered to patients. This solution was processed through the IV infusion system, mimicking the typical clinical administration setup - either with or without an in-line filter connected to the IV line. The samples generated thereafter were tested using various in vitro assays for activation of the innate immune system via cytokine release in whole blood and in peripheral blood mononuclear cell (PBMC) cultures, and activation of the Toll like receptors (TLRs). Activation of the adaptive immune system was evaluated by monitoring upregulation of surface receptors on dendritic cells (DCs) and CD4+ T cell proliferation in response to IV solution of Remicade®. Our results indicate that subvisible particles in Remicade®-saline solution have a significant role in activation of the immune system but there are extrinsic factors potentially contributed by the in-line filters or other process parameters that also contribute to immune system activation.

Biocompatibility and immunogenic response to recombinant honeybee silk material

If tolerated in biological environments, recombinant structural proteins offer the advantage that biological cues dictating cell attachment and material degradation can be modified as required for clinical application using genetic engineering. In this study, we investigate the biological response to materials generated from the recombinant honeybee silk protein, AmelF3, a structural protein that can be produced at high levels by fermentation in Escherichia coli. The protein can be readily purified from E. coli host cell proteins after transgenic production and fabricated into various material formats. When implanted subcutaneously according to International Standard ISO 10993 tests, materials generated from the purified recombinant protein were found to be noncytotoxic, inducing a transient weak immunogenic response and a chronic inflammatory response that resolved over time. While preliminary, this study supports the ongoing development of materials generated from this protein for biomedical applications. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 1763-1770, 2019.

Immunogenicity assessment of tbo-filgrastim in cancer patients receiving chemotherapy

AIM

This integrated analysis examined the immunogenicity of tbo-filgrastim and its potential clinical impact in three Phase III randomized studies in patients with breast cancer, lung cancer and non-Hodgkin lymphoma receiving chemotherapy.

RESULTS

Treatment-emergent antidrug antibodies (ADA) occurred in 3/213 (1.4%) breast cancer patients, 2/160 (1.3%) lung cancer patients and 1/63 (1.6%) patients with non-Hodgkin lymphoma. None of the treatment-emergent ADA showed cross-reactivity toward native granulocyte-colony stimulating factors or exhibited neutralizing activity against tbo-filgrastim. Among patients with treatment-emergent ADA, there was no treatment-related hypersensitivity or anaphylaxis and no evidence of loss of clinical efficacy.

CONCLUSION

Tbo-filgrastim has demonstrated low immunogenicity in cancer patients receiving chemotherapy and ADA response does not impact safety and efficacy in the patients.

Optical Detection of Degraded Therapeutic Proteins

The quality of therapeutic proteins such as hormones, subunit and conjugate vaccines, and antibodies is critical to the safety and efficacy of modern medicine. Identifying malformed proteins at the point-of-care can prevent adverse immune reactions in patients; this is of special concern when there is an insecure supply chain resulting in the delivery of degraded, or even counterfeit, drug product. Identification of degraded protein, for example human growth hormone, is demonstrated by applying automated anomaly detection algorithms. Detection of the degraded protein differs from previous applications of machine-learning and classification to spectral analysis: only example spectra of genuine, high-quality drug products are used to construct the classifier. The algorithm is tested on Raman spectra acquired on protein dilutions typical of formulated drug product and at sample volumes of 25 µL, below the typical overfill (waste) volumes present in vials of injectable drug product. The algorithm is demonstrated to correctly classify anomalous recombinant human growth hormone (rhGH) with 92% sensitivity and 98% specificity even when the algorithm has only previously encountered high-quality drug product.

Safety Evaluation of Lipid Nanoparticle-Formulated Modified mRNA in the Sprague-Dawley Rat and Cynomolgus Monkey

The pharmacology, pharmacokinetics, and safety of modified mRNA formulated in lipid nanoparticles (LNPs) were evaluated after repeat intravenous infusion to rats and monkeys. In both species, modified mRNA encoding the protein for human erythropoietin (hEPO) had predictable and consistent pharmacologic and toxicologic effects. Pharmacokinetic analysis conducted following the first dose showed that measured hEPO levels were maximal at 6 hours after the end of intravenous infusion and in excess of 100-fold the anticipated efficacious exposure (17.6 ng/ml) at the highest dose tested.²⁴ hEPO was pharmacologically active in both the rat and the monkey, as indicated by a significant increase in red blood cell mass parameters. The primary safety-related findings were caused by the exaggerated pharmacology of hEPO and included increased hematopoiesis in the liver, spleen, and bone marrow (rats) and minimal hemorrhage in the heart (monkeys). Additional primary safety-related findings in the rat included mildly increased white blood cell counts, changes in the coagulation parameters at all doses, as well as liver injury and release of interferon γ-inducible protein 10 in high-dose groups only. In the monkey, as seen with the parenteral administration of cationic LNPs, splenic necrosis and lymphocyte depletion were observed, accompanied with mild and reversible complement activation. These findings defined a well-tolerated dose level above the anticipated efficacious dose. Overall, these combined studies indicate that LNP-formulated modified mRNA can be administered by intravenous infusion in 2 toxicologically relevant test species and generate supratherapeutic levels of protein (hEPO) in vivo.

Microparticles and Nanoparticles Delivered in Intravenous Saline and in an Intravenous Solution of a Therapeutic Antibody Product

Intravenous (IV) infusion is used for administration of a large proportion of biologic therapeutics, including most monoclonal antibody products. In this study, we determined the subvisible particle levels in IV solutions and after the solutions were processed with an IV administration setup that mimicked the typical clinical method of administration. IV saline in bags manufactured by both Hospira and Baxter contained 1600-8000 microparticles/mL and 4-73 × 10⁶ nanoparticles/mL in solution. When IV immunoglobulin was diluted into the IV saline, 3700-23,000 microparticles/mL and 18-240 × 10⁶ nanoparticles/mL were detected. During processing of the solution through the IV system, in-line filters removed most microparticles. However, there were still 1-21 × 10⁶ nanoparticles/mL in IV saline and 7-83 × 10⁶ nanoparticles/mL in IV immunoglobulin diluted in saline. Finally, in samples processed through in-line filters, we found relatively large microparticles (20-60 μm) that were composed of protein or polycarbonate. These particles resulted from shedding of polycarbonate and sloughing off of protein films downstream from the filter membrane. Overall, the results document that even with in-line filters in place, high levels of subvisible particles are delivered to patients and there is a need for improved, more effective filters and IV solutions with lower particle levels.

Immunogenicity Assessment of Lipegfilgrastim in Patients with Breast Cancer Receiving Chemotherapy

Lipegfilgrastim is a long-acting, once-per-cycle, glycopegylated recombinant granulocyte colony-stimulating factor (G-CSF) used to prevent neutropenia in patients receiving myelosuppressive chemotherapy. This integrated analysis examined the immunogenicity of lipegfilgrastim and its potential clinical impact in two double-blind randomized studies (phases II and III) of patients with breast cancer receiving chemotherapy. Serum samples were analyzed using sequential assays for screening, confirmation, antibody titer, and characterization of antidrug antibodies (ADA). Neutropenia-related efficacy measures were reviewed for each ADA-positive patient. Among 255 patients receiving lipegfilgrastim (154 in phase II, 101 in phase III) and 155 patients receiving pegfilgrastim (54 in phase II, 101 in phase III), the incidence of treatment-emergent ADA was low and similar between the lipegfilgrastim (phase II: 1.3%; phase III: 1.0%) and pegfilgrastim (phase II: 1.9%; phase III: 1.0%) arms. None of the treatment-emergent ADA-positive samples exhibited neutralizing activity against lipegfilgrastim, pegfilgrastim, or glycosylated G-CSF in a cell-based neutralizing antibody assay. No changes were observed in neutropenia-related efficacy measures among ADA-positive patients, and no treatment-related hypersensitivity or anaphylaxis occurred. These results indicate that there is no apparent impact of ADA on lipegfilgrastim efficacy and safety.

Maillard reaction and immunogenicity of protein therapeutics

The recombinant DNA technology enabled the production of a variety of human therapeutic proteins. Accumulated clinical experience, however, indicates that the formation of antibodies against such proteins is a general phenomenon rather than an exception. The immunogenicity of therapeutic proteins results in inefficient therapy and in the development of undesired, sometimes life-threatening, side reactions. The human proteins, designed for clinical application, usually have the same amino acid sequence as their native prototypes and it is not yet fully clear what the reasons for their immunogenicity are. In previous studies we have demonstrated for the first time that interferon-β (IFN-β) pharmaceuticals, used for treatment of patients with multiple sclerosis, do contain advanced glycation end products (AGEs) that contribute to IFN-β immunogenicity. AGEs are the final products of a chemical reaction known as the Maillard reaction or glycation, which implication in protein drugs’ immunogenicity has been overlooked so far. Therefore, the aim of the present article is to provide a comprehensive overview on the Maillard reaction with emphasis on experimental data and theoretical consideration telling us why the Maillard reaction warrants special attention in the context of the well-documented protein drugs’ immunogenicity.

Neonatal Immune Tolerance Induction to Allow Long-Term Studies With an Immunogenic Therapeutic Monoclonal Antibody in Mice

The purpose of this study is to test the feasibility of neonatal immune tolerance induction in mice to enable long-term pharmacokinetic studies with immunogenic therapeutic monoclonal antibodies (mAb). Neonatal immune tolerance was induced by transfer of a mAb to neonatal mice via colostrum from nursing mother mice treated with two subcutaneous doses of a tolerogen starting within the first 24 h after delivery. Adalimumab and efalizumab were administered as tolerogens at various dose levels. Tolerance induction was evaluated in the offspring after reaching adulthood at 8 weeks of age. After a single intravenous injection of the same mAb as used for tolerance induction, the pharmacokinetics of the mAb and formation of anti-drug antibodies (ADA) in plasma were assessed using ELISA. Tolerance induction to adalimumab was achieved in a maternal dose-dependent manner. Adalimumab immune-tolerant offspring showed a slower adalimumab clearance (4.24 ± 0.32 mL/day/kg) as compared to the control group (12.09 ± 3.81 mL/day/kg). In the control group, accelerated clearance started 7 days after adalimumab dosing, whereas immune-tolerant offspring showed a log-linear terminal concentration-time course. In the offspring, the absence of predose ADA levels was indicative of successful tolerance induction. The second test compound efalizumab was not immunogenic in mice under our experimental conditions. Overall, the present study demonstrated the suitability of neonatal immune tolerance induction for a 4-week single dose study in adult mice with a human therapeutic mAb that is otherwise immunogenic in laboratory animals.

Modeling approach to investigate the effect of neonatal Fc receptor binding affinity and anti-therapeutic antibody on the pharmacokinetic of humanized monoclonal anti-tumor necrosis factor-α IgG antibody in cynomolgus monkey

PURPOSE

Several neonatal Fc receptor (FcRn) variants of an anti-tumor necrosis factor (TNF)-α humanized monoclonal IgG antibodies (mAbs) were developed but the effect of their differential FcRn binding affinities on pharmacokinetic (PK) behavior were difficult to be definitively measured in vivo due to formation of anti-therapeutic antibody (ATA). A semi-mechanistic model was developed to investigate the quantitative relationship between the FcRn binding affinity and PK of mAbs in cynomolgus monkey with the presence of ATA.

METHODS

PK and ATA data from cynomolgus monkeys which received a single intravenous dose of adalimumab, wild-type or two FcRn variant (N434H and N434A) anti-TNF-α mAbs were included in the analysis. Likelihood-based censored data handling method was used to include many PK observations with BQL values for model development. A fully integrated PK-ATA model was developed and used to fit simultaneously to the PK/ATA data.

RESULTS AND CONCLUSIONS

The PK and ATA time-profiles and effect of FcRn-binding affinity on PK of mAbs were well described by the model and the parameters were estimated with good precision. The model was used successfully to construct quantitative relationships between FcRn binding affinity and PK of anti-TNF-α mAbs in the presence of the ATA-mediated elimination and interferences.

Assessment of collagen-induced arthritis using cyanine 5.5 conjugated with hydrophobically modified glycol chitosan nanoparticles: correlation with 18F-fluorodeoxyglucose positron emission tomography data

OBJECTIVE

To evaluate the potential and correlation between near-infrared fluorescence (NIRF) imaging using cyanine 5.5 conjugated with hydrophobically modified glycol chitosan nanoparticles (HGC-Cy5.5) and (18)F-fluorodeoxyglucose-positron emission tomography ((18)F-FDG-PET) imaging of collagen-induced arthritis (CIA).

MATERIALS AND METHODS

We used 10 CIA and 3 normal mice. Nine days after the injecting collagen twice, microPET imaging was performed 40 minutes after the intravenous injection of 9.3 MBq (18)F-FDG in 200 µL PBS. One day later, NIRF imaging was performed two hours after the intravenous injection of HGC-cy5.5 (5 mg/kg). We assessed the correlation between these two modalities in the knees and ankles of CIA mice.

RESULTS

The mean standardized uptake values of (18)F-FDG for knees and ankles were 1.68 ± 0.76 and 0.79 ± 0.71, respectively, for CIA mice; and 0.57 ± 0.17 and 0.54 ± 0.20 respectively for control mice. From the NIRF images, the total photon counts per 30 mm(2) for knees and ankles were 2.32 ± 1.54 × 10(5) and 2.75 ± 1.51 × 10(5), respectively, for CIA mice, and 1.22 ± 0.27 × 10(5) and 0.88 ± 0.24 × 10(5), respectively, for control mice. These two modalities showed a moderate correlation for knees (r = 0.604, p = 0.005) and ankles (r = 0.464, p = 0.039). Moreover, both HGC-Cy5.5 (p = 0.002) and (18)F-FDG-PET (p = 0.005) imaging also showed statistically significant differences between CIA and normal mice.

CONCLUSION

NIRF imaging using HGC-Cy5.5 was moderately correlated with (18)F-FDG-PET imaging in the CIA model. As such, HGC-Cy5.5 imaging can be used for the early detection of rheumatoid arthritis.

Biochemical and biophysical characterization of humanized IgG1 produced in Pichia pastoris

The first full length IgG produced in Pichia pastoris was reported in late 1980. However, use of a wild-type Pichia expression system to produce IgGs with human-like N-linked glycans was not possible until recently. Advances in glycoengineering have enabled organisms such as Pichia to mimic human N-glycan biosynthesis and produce IgGs with human glycans on an industrial scale. Since there are only a few reports of the analytical characterization of Pichia-produced IgG, we summarize the results known in this field, and provide additional characterization data generated in our laboratories. The data suggest that Pichia-produced IgG has the same stability as that produced in Chinese hamster ovary (CHO) cells. It has similar aggregation profiles, charge variant distribution and oxidation levels as those for a CHO IgG. It contains human N-linked glycans and O-linked single mannose. Because of the comparable biophysical and biochemical characteristics, glycoengineered Pichia pastoris is an attractive expression system for therapeutic IgG productions.

Post-production protein stability: trouble beyond the cell factory

Being protein function a conformation-dependent issue, avoiding aggregation during production is a major challenge in biotechnological processes, what is often successfully addressed by convenient upstream, midstream or downstream approaches. Even when obtained in soluble forms, proteins tend to aggregate, especially if stored and manipulated at high concentrations, as is the case of protein drugs for human therapy. Post-production protein aggregation is then a major concern in the pharmaceutical industry, as protein stability, pharmacokinetics, bioavailability, immunogenicity and side effects are largely dependent on the extent of aggregates formation. Apart from acting at the formulation level, the recombinant nature of protein drugs allows intervening at upstream stages through protein engineering, to produce analogue protein versions with higher stability and enhanced therapeutic values.

Technology comparisons for anti-therapeutic antibody and neutralizing antibody assays in the context of an anti-TNF pharmacokinetic study

A single-dose cynomolgus monkey pharmacokinetic study was performed comparing two monoclonal anti-TNF antibodies (mAbs), GNExTNFvF and Humira. Normal pharmacokinetic profiles were observed over the first week of the study, followed by a rapid drop in serum mAb levels after day 8. In order to determine whether an anti-therapeutic antibody (ATA) response led to the abnormal clearance of antibody in this study, ATA assays were developed using two electrochemiluminescent technologies, BioVeris and Meso Scale Discovery (MSD). Characterization of the assays demonstrated that the two platforms gave similar sensitivities and tolerance to the presence of therapeutic antibody. Analysis of the cynomolgus monkey serum samples revealed that all animals developed significant ATA titers with log titer values of 2-4, with the BioVeris and MSD technologies giving very similar results. Immunodepletion studies confirmed the CDR-specificity of the ATA response for the GNExTNFvF-dosed cynos, although the Humira-dosed cynos showed both CDR-specific and human IgG1 framework-specific ATAs. To further characterize the ATA response, neutralizing antibody (NAb) assays were developed using two different approaches, flow cytometry and MSD. Flow cytometry and MSD cell-binding assays used Jurkat cells transfected with noncleavable TNF (huTNF(NC)). Neutralizing activity was assessed by the ability of ATA-positive serum samples to block the binding of biotinylated anti-TNF to huTNF(NC) Jurkat cells, showing that all but one animal developed neutralizing antibodies. Although both technologies displayed similar trends, the MSD approach showed greater differentiation between samples and could detect a broader range of neutralizing activities.

New preparations comprising recombinant human growth hormone: deliberations on the issue of biosimilars

Manufactured recombinant human GH (rhGH) has been available for more than 25 years. In the meantime, the GH produced by various manufacturers has been approved for application in replacement therapy in children and adults with GH deficiency or a number of disorders involving small stature in children. Until recently approval for each individual diagnosis was only granted after extensive studies on the long-term efficacy (e.g. adult height reached) and safety of the various products. Meanwhile, the European approving agency, the European Medicines Evaluation Agency (EMEA), has relinquished this restrictive stance. Thus, new rhGH preparations can count on gaining approval for existing indications even without conducting standard clinical studies of their efficacy and safety for each of these indications. The EMEA's reconsideration is apparently based on the rationale that recombinant GH can, in effect, be considered equivalent to the tried and tested preparations in wide use, provided certain specifications are met. The term 'biosimilars' was coined to denote the similarities between the products rather than their parity, as is the case with generics for instance. The higher complexity of biopharmaceuticals relates not only to the substances themselves but also to the manufacturing process. It is generally believed that modifications to a manufacturing process - which are a prerequisite for a patent - may cause modifications of the active substance which then may lead to different long-term effects. Thus, the term 'biosimilar' does not indicate that complex biopharmaceuticals deriving from the same substance are entirely identical, nor does the approval of a 'biosimilar' ensure this. The factual information provided here is offered towards clarification of some uncertainties and as a contribution towards resolving open questions relating to the topic of biosimilars. The final choice of product to be prescribed must be made by the informed, independent physician.

Toxicity as a result of immunostimulation by biologics

The immune system has evolved highly effective mechanisms of surveillance and defense against foreign pathogens, and is also thought to act in surveillance and suppression of cancer. Thus, a predominant goal of immune system-based therapies is to normalize or enhance the host immune response in the areas of infectious disease and oncology. This review considers general approaches used for therapeutic immunostimulation, alterations in immune response mechanisms that occur with these treatments and the syndromes that commonly arise as a result of these changes. Because nonclinical studies of these therapies are conducted in animal models as the basis for predicting potential human toxicities, this review also considers the value of nonclinical testing to predict human toxicity.

A role for protein misfolding in immunogenicity of biopharmaceuticals

For largely unknown reasons, biopharmaceuticals evoke potentially harmful antibody formation. Such antibodies can inhibit drug efficacy and, when directed against endogenous proteins, cause life-threatening complications. Insight into the mechanisms by which biopharmaceuticals break tolerance and induce an immune response will contribute to finding solutions to prevent this adverse effect. Using a transgenic mouse model, we here demonstrate that protein misfolding, detected with the use of tissue-type plasminogen activator and thioflavin T, markers of amyloid-like properties, results in breaking of tolerance. In wild-type mice, misfolding enhances protein immunogenicity. Several commercially available biopharmaceutical products were found to contain misfolded proteins. In some cases, the level of misfolded protein was found to increase upon storage under conditions prescribed by the manufacturer. Our results indicate that misfolding of therapeutic proteins is an immunogenic signal and a risk factor for immunogenicity. These findings offer novel possibilities to detect immunogenic protein entities with tPA and reduce immunogenicity of biopharmaceuticals.

Immunogenic and allergenic potentials of natural and recombinant innocuous proteins

A new aspect of protein immunogenic and allergenic properties has become important recently, when there is a higher chance that our immune system will be exposed to novel protein antigens and/or familiar protein antigens with an unprecedented high frequency and large amount. These proteins are innocuous, nontoxic, and noninvasive by themselves, and include various natural proteins from the environment and recombinant proteins from industry. The technical term allergenic has been used for such proteins and their abilities to induce specific IgE production and to cross-link IgE/Fc epsilonRI on the surface of mast cells and basophiles have been recognized. As for the environmental proteins, some physicochemical properties (solubility, stability, and permeability across a mucosal epithelium) of the proteins indirectly play important roles in their allergenic potential because they do not originate from invasive pathogens as vehicles. Indeed, several lines of experimental evidences have been accumulated indicating that all proteins are absorbed across mucosal epithelia by transcellular transport and/or through interstitial spaces among the epithelial cells but not at equal levels. Some animal models have been established for natural sensitization to some allergenic proteins by feeding or intragastric administration without an adjuvant and, in a few cases, some symptoms resembling human allergy and even anaphylaxis have been induced by oral challenge with the proteins. Sometimes, even to self-proteins, the immunogenic or allergenic potential is given by post-translational modifications and possibly by unknown structural/conformational alterations, when they are exogenous self-proteins, such as recombinant human proteins for drug use. Despite the accumulation of knowledge and the progress in analytical technology on protein allergenicity, it is still crucial to predict the allergenic potential of novel and unused proteins. However, some animal models are applicable for assessing the relative allergenic potential of processed proteins in comparison with that of native proteins in preclinical studies.

Factors of importance for a successful delivery system for proteins

Protein pharmaceuticals have matured into an important class of drugs, now comprising one in three novel drugs introduced on the market. However, significant gains are still to be made in reducing the costs of production, ensuring proper pharmacokinetics and efficacy, increasing patient compliance and convenience, and reducing side effects such as immunogenicity. This review summarises these issues and provides recent examples of methods to reduce costs, alter pharmacokinetics and increase patient compliance. It also discusses the increasing interest in understanding immunogenicity in order to prevent failure of the protein drug or serious life-threatening side effects due to autoimmunogenicity.