Nonintuitive Immunogenicity and Plasticity of Alpha-Synuclein Conformers: A Paradigm for Smart Delivery of Neuro-Immunotherapeutics

Despite the extensive research successes and continuous developments in modern medicine in terms of diagnosis, prevention, and treatment, the lack of clinically useful disease-modifying drugs or immunotherapeutic agents that can successfully treat or prevent neurodegenerative diseases is an ongoing challenge. To date, only one of the 244 drugs in clinical trials for the treatment of neurodegenerative diseases has been approved in the past decade, indicating a failure rate of 99.6%. In corollary, the approved monoclonal antibody did not demonstrate significant cognitive benefits. Thus, the prevalence of neurodegenerative diseases is increasing rapidly. Therefore, there is an urgent need for creative approaches to identifying and testing biomarkers for better diagnosis, prevention, and disease-modifying strategies for the treatment of neurodegenerative diseases. Overexpression of the endogenous α-synuclein has been identified as the driving force for the formation of the pathogenic α-synuclein (α-Syn) conformers, resulting in neuroinflammation, hypersensitivity, endogenous homeostatic responses, oxidative dysfunction, and degeneration of dopaminergic neurons in Parkinson's disease (PD). However, the conformational plasticity of α-Syn proffers that a certain level of α-Syn is essential for the survival of neurons. Thus, it exerts both neuroprotective and neurotoxic (regulatory) functions on neighboring neuronal cells. Furthermore, the aberrant metastable α-Syn conformers may be subtle and difficult to detect but may trigger cellular and molecular events including immune responses. It is well documented in literature that the misfolded α-Syn and its conformers that are released into the extracellular space from damaged or dead neurons trigger the innate and adaptive immune responses in PD. Thus, in this review, we discuss the nonintuitive plasticity and immunogenicity of the α-Syn conformers in the brain immune cells and their physiological and pathological consequences on the neuroimmune responses including neuroinflammation, homeostatic remodeling, and cell-specific interactions that promote neuroprotection in PD. We also critically reviewed the novel strategies for immunotherapeutic delivery interventions in PD pathogenesis including immunotherapeutic targets and potential nanoparticle-based smart drug delivery systems. It is envisioned that a greater understanding of the nonintuitive immunogenicity of aberrant α-Syn conformers in the brain's microenvironment would provide a platform for identifying valid therapeutic targets and developing smart brain delivery systems for clinically effective disease-modifying immunotherapeutics that can aid in the prevention and treatment of PD in the future.

Comparison of Protein-like Model Particles Fabricated by Micro 3D Printing to Established Standard Particles

Innovative analytical instruments and development of new methods has provided a better understanding of protein particle formation in biopharmaceuticals but have also challenged the ability to obtain reproducible and reliable measurements. The need for protein-like particle standards mimicking the irregular shape, translucent nature and near-to-neutral buoyancy of protein particles remained one of the hot topics in the field of particle detection and characterization in biopharmaceutical formulations. An innovative protein-like particle model has been developed using two photo polymerization (2PP) printing allowing to fabricate irregularly shaped particles with similar properties as protein particles at precise size of 50 µm and 150 µm, representative of subvisible particles and visible particles, respectively. A study was conducted to compare the morphological, physical, and optical properties of artificially generated protein particles, polystyrene spheres, ETFE, and SU-8 particle standards, along with newly developed protein-like model particles manufactured using 2PP printing. Our results suggest that 2PP printing can be used to produce protein-like particle standards that might facilitate harmonization and standardization of subvisible and visible protein particle characterization across laboratories and organizations.

Immunogenicity of Therapeutic Biological Modalities - Lessons from Hemophilia A Therapies

The introduction and development of biologics such as therapeutic proteins, gene-, and cell-based therapy have revolutionized the scope of treatment for many diseases. However, a significant portion of the patients develop unwanted immune reactions against these novel biological modalities, referred to as immunogenicity, and no longer benefit from the treatments. In the current review, using Hemophilia A (HA) therapy as an example, we will discuss the immunogenicity issue of multiple biological modalities. Currently, the number of therapeutic modalities that are approved or recently explored to treat HA, a hereditary bleeding disorder, is increasing rapidly. These include, but are not limited to, recombinant factor VIII proteins, PEGylated FVIII, FVIII Fc fusion protein, bispecific monoclonal antibodies, gene replacement therapy, gene editing therapy, and cell-based therapy. They offer the patients a broader range of more advanced and effective treatment options, yet immunogenicity remains the most critical complication in the management of this disorder. Recent advances in strategies to manage and mitigate immunogenicity will also be reviewed.

Characterizing Silicone Oil-Induced Protein Aggregation with Stimulated Raman Scattering Imaging

Particles in biopharmaceutical products present high risks due to their detrimental impacts on product quality and safety. Identification and quantification of particles in drug products are important to understand particle formation mechanisms, which can help develop control strategies for particle formation during the formulation development and manufacturing process. However, existing analytical techniques such as microflow imaging and light obscuration measurement lack the sensitivity and resolution to detect particles with sizes smaller than 2 μm. More importantly, these techniques are not able to provide chemical information to determine particle composition. In this work, we overcome these challenges by applying the stimulated Raman scattering (SRS) microscopy technique to monitor the C-H Raman stretching modes of the proteinaceous particles and silicone oil droplets formed in the prefilled syringe barrel. By comparing the relative signal intensity and spectral features of each component, most particles can be classified as protein-silicone oil aggregates. We further show that morphological features are poor indicators of particle composition. Our method has the capability to quantify aggregation in protein therapeutics with chemical and spatial information in a label-free manner, potentially allowing high throughput screening or investigation of aggregation mechanisms.

Protein Aggregates in Inhaled Biologics: Challenges and Considerations

Pulmonary delivery is the main route of administration for treatment of local lung diseases. Recently, the interest in delivery of proteins through the pulmonary route for treatment of lung diseases has significantly increased, especially after Covid-19 pandemic. The development of an inhalable protein combines the challenges of inhaled as well as biologic products since protein stability may be compromised during manufacture or delivery. For instance, spray drying is the most common technology for manufacture of inhalable biological particles, however, it imposes shear and thermal stresses which may cause protein unfolding and aggregation post drying. Therefore, protein aggregation should be evaluated for inhaled biologics as it could impact the safety and/or efficacy of the product. While there is extensive knowledge and regulatory guidance on acceptable limits of particles, which inherently include insoluble protein aggregates, in injectable proteins, there is no comparable knowledge for inhaled ones. Moreover, the poor correlation between in vitro setup for analytical testing and the in vivo lung environment limits the predictability of protein aggregation post inhalation. Thus, the purpose of this article is to highlight the major challenges facing the development of inhaled proteins compared to parenteral ones, and to share future thoughts to resolve them.

An Intercompany Perspective on Practical Experiences of Predicting, Optimizing and Analyzing High Concentration Biologic Therapeutic Formulations

Developing high-dose biologic drugs for subcutaneous injection often requires high-concentration formulations and optimizing viscosity, solubility, and stability while overcoming analytical, manufacturing, and administration challenges. To understand industry approaches for developing high-concentration formulations, the Formulation Workstream of the BioPhorum Development Group, an industry-wide consortium, conducted an inter-company collaborative exercise which included several surveys. This collaboration provided an industry perspective, experience, and insight into the practicalities for developing high-concentration biologics. To understand solubility and viscosity, companies desire predictive tools, but experience indicates that these are not reliable and experimental strategies are best. Similarly, most companies prefer accelerated and stress stability studies to in-silico or biophysical-based prediction methods to assess aggregation. In addition, optimization of primary container-closure and devices are pursued to mitigate challenges associated with high viscosity of the formulation. Formulation strategies including excipient selection and application of studies at low concentration to high-concentration formulations are reported. Finally, analytical approaches to high concentration formulations are presented. The survey suggests that although prediction of viscosity, solubility, and long-term stability is desirable, the outcome can be inconsistent and molecule dependent. Significant experimental studies are required to confirm robust product definition as modeling at low protein concentrations will not necessarily extrapolate to high concentration formulations.

Evaluation of a Raman Chemometric Method for Detecting Protein Structural Conformational Changes in Solution

Raman scattering shows promise as a powerful routine tool, to determine both secondary and the smaller tertiary structural changes that precede aggregation in both solutions and solids. A method was developed utilizing principal component analysis (PCA) of Raman spectra for detection of small, but meaningful, pH induced changes in tertiary protein structure linked to aggregate formation using α-lactalbumin solutions as a model. The sample preparation and spectral parameters, were optimized for a bulk Raman probe. Analysis of large regions (600-1850 cm^-1) yielded principal component (PC) scores useful for semi-quantitative comparison of protein conformation between formulations. PC loadings corresponded to specific structural peaks known to change with solution pH. PCA of circular dichroism (CD) spectra of dilute solutions yielded similar results. Sucrose is a common formulation excipient with a Raman spectrum that overlaps many protein peaks. With sucrose in the protein solution, the ability of PCA to discern protein structural changes from the Raman spectra was somewhat reduced. Analysis of a more limited spectral region (1530-1780 cm^-1) with negligible sucrose spectral contribution improved the discrimination of protein conformational states. The new Raman method accurately distinguished differences in protein structure in concentrated solutions. The long-term goal is to explore Raman characterization as a routine monitoring tool of protein stability in both solution and solid states.

In vitro and in vivo immunogenicity assessment of protein aggregate characteristics

The immunogenicity risk of therapeutic protein aggregates has been extensively investigated over the past decades. While it is established that not all aggregates are equally immunogenic, the specific aggregate characteristics, which are most likely to induce an immune response, remain ambiguous. The aim of this study was to perform comprehensive in vitro and in vivo immunogenicity assessment of human insulin aggregates varying in size, structure and chemical modifications, while keeping other morphological characteristics constant. We found that flexible aggregates with highly altered secondary structure were most immunogenic in all setups, while compact aggregates with native-like structure were found to be immunogenic primarily in vivo. Moreover, sub-visible (1-100 µm) aggregates were found to be more immunogenic than sub-micron (0.1-1 µm) aggregates, while chemical modifications (deamidation, ethylation and covalent dimers) were not found to have any measurable impact on immunogenicity. The findings highlight the importance of utilizing aggregates varying in few characteristics for assessment of immunogenicity risk of specific morphological features and may provide a workflow for reliable particle analysis in biotherapeutics.

Subtle pH variation around pH 4.0 affects aggregation kinetics and aggregate characteristics of recombinant human insulin

Insulin is a biotherapeutic protein, which, depending on environmental conditions such as pH, has been shown to form a large variety of aggregates with different structures and morphologies. This work focuses on the formation and characteristics of insulin particulates, dense spherical aggregates having diameters spanning from nanometre to low-micron size. An in-depth investigation of the system is obtained by applying a broad range of techniques for particle sizing and characterisation. An interesting observation was achieved regarding the formation kinetics and aggregate characteristics of the particulates; a subtle change in the pH from pH 4.1 to pH 4.3 markedly affected the kinetics of the particulate formation and led to different particulate sizes, either nanosized or micronsized particles. Also, a clear difference between the secondary structure of the protein particulates formed at the two pH values was observed, where the nanosized particulates had an increased content of aggregated β-structure compared to the micronsized particles. The remaining characteristics of the particles were identical for the two particulate populations. These observations highlight the importance of carefully studying the formulation design space and of knowing the impact of parameters such as pH on the aggregation to secure a drug product in control. Furthermore, the identification of particles only varying in few parameters, such as size, are considered highly valuable for studying the effect of particle features on the immunogenicity potential.

Molecular Docking, Dynamics, and WaterSwap Analysis to Identify Anti-aggregating Agents of Insulin and IFN-β

There are several challenges in the development, and formulation of biologics, particularly concerning their physical stabilities. The self-assembly of peptides like human insulin and interferon beta (IFN-β) has potential to form aggregates in pharmaceutical formulation. Therefore, it is a significant problem in the manufacturing, storage, and delivery of insulin and IFN-β formulations. Amino acids as aggregation suppressing additives have been used to stabilize proteins during manufacturing and storage. Several changes to the B chain's C-terminus have been proposed in an attempt to improve insulin formulation. The core segments of the A and B chains (SLYQLENY and LVEALYLV) have recently been identified as sheet-forming areas, and their microcrystalline structures have been exploited to construct a high-resolution insulin amyloid fibril model. Here, we have chosen twenty-one amino acids to develop as additives in rendering the insulin and IFN-β aggregations. Thereafter, integrated molecular docking studies of single layer monomers of full-length insulin and IFN-β have been performed to identify structural elements (amino acids) that can act as disaggregating agents. The stability of the best-docked amino acid complexes was judged using molecular dynamics studies. Finally, phenylalanine was identified as a disaggregation agent for insulin, and lysine, tyrosine, phenylalanine, and tryptophan were identified as disaggregation agents for IFN-β from the molecular dynamics study. These findings may open a novel proposal to explore further in vitro studies to increase the stability of the insulin and IFN-β formulation.

Bioconjugation strategies and clinical implications of Interferon-bioconjugates

Interferons (IFN) are immunomodulating, antiviral and antiproliferative cytokines for treatment of multiple indications, including cancer, hepatitis, and autoimmune disease. The first IFNs were discovered in 1957, first approved in 1986, and are nowadays listed in the WHO model list of essential Medicines. Three classes of IFNs are known; IFN-α2a and IFN-β belonging to type-I IFNs, IFN-γ a type-II IFN approved for some hereditary diseases and IFN-λs, which form the newest class of type-III IFNs. IFN-λs were discovered in the last decade with fascinating yet under discovered pharmaceutical potential. This article reviews available IFN drugs, their field and route of application, while also outlining available and future strategies for bioconjugation to further optimize pharmaceutical and clinical performances of all three available IFN classes.

Particles in Biopharmaceutical Formulations, Part 2: An Update on Analytical Techniques and Applications for Therapeutic Proteins, Viruses, Vaccines and Cells

Particles in biopharmaceutical formulations remain a hot topic in drug product development. With new product classes emerging it is crucial to discriminate particulate active pharmaceutical ingredients from particulate impurities. Technical improvements, new analytical developments and emerging tools (e.g., machine learning tools) increase the amount of information generated for particles. For a proper interpretation and judgment of the generated data a thorough understanding of the measurement principle, suitable application fields and potential limitations and pitfalls is required. Our review provides a comprehensive overview of novel particle analysis techniques emerging in the last decade for particulate impurities in therapeutic protein formulations (protein-related, excipient-related and primary packaging material-related), as well as particulate biopharmaceutical formulations (virus particles, virus-like particles, lipid nanoparticles and cell-based medicinal products). In addition, we review the literature on applications, describe specific analytical approaches and illustrate advantages and drawbacks of currently available techniques for particulate biopharmaceutical formulations.

Quantitative Evaluation of Insoluble Particulate Matters in Therapeutic Protein Injections Using Light Obscuration and Flow Imaging Methods

Flow imaging (FI) has emerged as a powerful tool to evaluate insoluble particles derived from protein aggregates as an orthogonal method to light obscuration (LO). However, few reports directly compare the FI and LO method in the size and number of protein particles in commercially available therapeutic protein injections. In this study, we measured the number of insoluble particles in several therapeutic protein injections using both FI and LO, and characterized these particles to compare the analytical performance of the methods. The particle counts measured using FI were much higher than those measured using LO, and the difference depended on the products or features of particles. Some products contained a large number of transparent and elongated particles, which could escape detection using LO. Our results also suggested that the LO method underestimates the size and number of silicone oil droplets in prefilled syringe products compared to the FI method. The count of particles ≥10 μm in size in one product measured using FI exceeded the criteria (6000 counts per container) defined in the compendial particulate matter test using the LO method. Thus precaution should be taken when setting the acceptance criteria of specification tests using the FI method.

Subvisible Particle Analysis of 17 Monoclonal Antibodies Approved in China Using Flow Imaging and Light Obscuration

In the study, subvisible particles in 205 samples from 17 commercial mAb drug products approved in China were analyzed using light obscuration (LO) and flow imaging microscopy (FIM) methods. For each method, a total 633 tests (runs) were performed. In the tests, samples in state of lyophilized powder or syringe package had significantly higher particle concentrations. It was confirmed by analyzing the 205 drug product samples that FIM particle counts are generally higher than LO counts. The cause of the higher counts of FIM method than LO counts was examined by looking into the contribution of proteinaceous, translucent particles in the samples. The data of the study showed that the number of proteinaceous, translucent particles was a factor in the elevated counts of FIM method compared to LO method.

Aggregation of protein therapeutics enhances their immunogenicity: causes and mitigation strategies

Protein aggregation in biotherapeutics has been identified to increase immunogenicity, leading to immune-mediated adverse effects, such as severe allergic responses including anaphylaxis. The induction of anti-drug antibodies (ADAs) moreover enhances drug clearance rates, and can directly block therapeutic function. In this review, identified immune activation mechanisms triggered by protein aggregates are discussed, as well as physicochemical properties of aggregates, such as size and shape, which contribute to immunogenicity. Furthermore, factors which contribute to protein stability and aggregation are considered. Lastly, with these factors in mind, we encourage an innovative and multidisciplinary approach with regard to further research in the field, with the overall aim to avoid immunogenic aggregation in future drug development.

Application of ultraviolet, visible, and infrared light imaging in protein-based biopharmaceutical formulation characterization and development studies

Imaging is increasingly more utilized as analytical technology in biopharmaceutical formulation research, with applications ranging from subvisible particle characterization to thermal stability screening and residual moisture analysis. This review offers a comprehensive overview of analytical imaging for scientists active in biopharmaceutical formulation research and development, where it presents the unique information provided by the ultraviolet (UV), visible (Vis), and infrared (IR) sections in the electromagnetic spectrum. The main body of this review consists of an outline of UV, Vis, and IR imaging techniques for several (bio)physical properties that are commonly determined during protein-based biopharmaceutical formulation characterization and development studies. The review concludes with a future perspective of applied imaging within the field of biopharmaceutical formulation research.

Analytical methods for process and product characterization of recombinant adeno-associated virus-based gene therapies

The optimization of upstream and downstream processes for production of recombinant adeno-associated virus (rAAV) with consistent quality depends on the ability to rapidly characterize critical quality attributes (CQAs). In the context of rAAV production, the virus titer, capsid content, and aggregation are identified as potential CQAs, affecting the potency, purity, and safety of rAAV-mediated gene therapy products. Analytical methods to measure these attributes commonly suffer from long turnaround times or low throughput for process development, although rapid, high-throughput methods are beginning to be developed and commercialized. These methods are not yet well established in academic or industrial practice, and supportive data are scarce. Here, we review both established and upcoming analytical methods for the quantification of rAAV quality attributes. In assessing each method, we highlight the progress toward rapid, at-line characterization of rAAV. Furthermore, we identify that a key challenge for transitioning from traditional to newer methods is the scarcity of academic and industrial experience with the latter. This literature review serves as a guide for the selection of analytical methods targeting quality attributes for rapid, high-throughput process characterization during process development of rAAV-mediated gene therapies.

Rationale for COVID-19 Treatment by Nebulized Interferon-β-1b-Literature Review and Personal Preliminary Experience

The inflammatory response to COVID-19 is specifically associated with an impaired type I interferon (IFN) response and complete blockade of IFN-β secretion. Clinically, nebulization of IFN-α-2b has been historically used in China to treat viral pneumonia associated with SARS-CoV. Very recent data show that the use of inhaled type I IFN is associated with decreased mortality in Chinese COVID-19 patients. However, IFN nebulization is currently not standard in Europe and the United States. Therefore, our group has set up a project aimed to evaluate the possibility to nebulize IFN-β-1b (a drug currently used in Europe to treat multiple sclerosis via subcutaneous injections) and to assess the safety of this new mode of administration in SARS-CoV-2 infected patients. We present here literature data that allowed us to build our hypothesis and to develop collaboration between clinical pharmacists, intensivists and nebulization engineers in order to gain first pre-clinical and clinical experience of IFN-β-1b nebulization. After validation of the nebulization method and verification of droplet size compatible with nebulization, the method has been applied to four intensive care patients treated at our university hospital, for whom none of the COVID-19 therapies initially used in France led to significant clinical improvement. All patients exhibited negative viral carriage and experienced clinical improvement 7-16 days after having initiated nebulized IFN-β-1b inhalation therapy. No side effects were observed. All patients were alive within a 90-days follow-up. Although it is not possible to draw firm conclusions on treatment efficacy based on this case report, our study shows that pulmonary IFN-β-1b administration is feasible, with a good safety profile. This procedure, which presents the advantage of directly targeting the lungs and reducing the risks of systemic side effects, may represent a promising therapeutic strategy for the care of patients with severe COVID-19. However, our preliminary observation requires confirmation by randomized controlled trials.

Treatment- and population-specific genetic risk factors for anti-drug antibodies against interferon-beta: a GWAS

BACKGROUND

Upon treatment with biopharmaceuticals, the immune system may produce anti-drug antibodies (ADA) that inhibit the therapy. Up to 40% of multiple sclerosis patients treated with interferon β (IFNβ) develop ADA, for which a genetic predisposition exists. Here, we present a genome-wide association study on ADA and predict the occurrence of antibodies in multiple sclerosis patients treated with different interferon β preparations.

METHODS

We analyzed a large sample of 2757 genotyped and imputed patients from two cohorts (Sweden and Germany), split between a discovery and a replication dataset. Binding ADA (bADA) levels were measured by capture-ELISA, neutralizing ADA (nADA) titers using a bioassay. Genome-wide association analyses were conducted stratified by cohort and treatment preparation, followed by fixed-effects meta-analysis.

RESULTS

Binding ADA levels and nADA titers were correlated and showed a significant heritability (47% and 50%, respectively). The risk factors differed strongly by treatment preparation: The top-associated and replicated variants for nADA presence were the HLA-associated variants rs77278603 in IFNβ-1a s.c.- (odds ratio (OR) = 3.55 (95% confidence interval = 2.81-4.48), p = 2.1 × 10-26) and rs28366299 in IFNβ-1b s.c.-treated patients (OR = 3.56 (2.69-4.72), p = 6.6 × 10-19). The rs77278603-correlated HLA haplotype DR15-DQ6 conferred risk specifically for IFNβ-1a s.c. (OR = 2.88 (2.29-3.61), p = 7.4 × 10-20) while DR3-DQ2 was protective (OR = 0.37 (0.27-0.52), p = 3.7 × 10-09). The haplotype DR4-DQ3 was the major risk haplotype for IFNβ-1b s.c. (OR = 7.35 (4.33-12.47), p = 1.5 × 10-13). These haplotypes exhibit large population-specific frequency differences. The best prediction models were achieved for ADA in IFNβ-1a s.c.-treated patients. Here, the prediction in the Swedish cohort showed AUC = 0.91 (0.85-0.95), sensitivity = 0.78, and specificity = 0.90; patients with the top 30% of genetic risk had, compared to patients in the bottom 30%, an OR = 73.9 (11.8-463.6, p = 4.4 × 10-6) of developing nADA. In the German cohort, the AUC of the same model was 0.83 (0.71-0.92), sensitivity = 0.80, specificity = 0.76, with an OR = 13.8 (3.0-63.3, p = 7.5 × 10-4).

CONCLUSIONS

We identified several HLA-associated genetic risk factors for ADA against interferon β, which were specific for treatment preparations and population backgrounds. Genetic prediction models could robustly identify patients at risk for developing ADA and might be used for personalized therapy recommendations and stratified ADA screening in clinical practice. These analyses serve as a roadmap for genetic characterizations of ADA against other biopharmaceutical compounds.

Stability and Activity of the Hyperglycosylated Human Interferon-β R27T Variant

A hyperglycosylated recombinant human interferon-β (rhIFN-β) R27T mutant was established to improve relapsing-remitting multiple sclerosis (RRMS) in our previous study. We focused on the stability of the R27T mutant throughout its production lifetime, including culture, purification, and storage before formulation prior to clinical use. Herein, we address the stability of this protein during optimized culture and purification processes. Additionally, we employed artificial stress conditions during culture and purification to characterize R27T instability. Although, among total R27T, relative native R27T ratio displayed transiently low even under optimized production process, the ratio was recovered by the end of the overall production process, suggesting that culture and purification processes are optimized. Artificial stress during culture and purification processes resulted in degradation of R27T acidic and basic variants, and mismatched disulfide bonds in no-aggregated forms as well as in the aggregated form. The presence of disulfide bond exchange without aggregation in the unfolded/misfolded state could be a novel finding for rhIFN-β products. The results provide meaningful information for the comprehensive evaluation of the stability of the R27T variant.

Critical analysis of techniques and materials used in devices, syringes, and needles used for intravitreal injections

Intravitreal injections have become the most commonly performed intraocular treatments worldwide. Because intravitreal injections may induce severe adverse events, such as infectious and noninfectious endophthalmitis, cataract, ocular hypertension, vitreous hemorrhage, or retinal detachment, appropriate awareness of the materials and techniques used are essential to reduce these sight-threatening complications. This review provides insights into the needles, syringes, silicone oil coating, sterilization methods, devices to assist intravitreal injections, scleral piercing techniques using needles, syringe handling, anesthesia, and safety issues related to materials and techniques. It is paramount that physicians be aware of every step involved in intravitreal injections and consider the roles and implications of all materials and techniques used. The ability to understand the theoretical and practical circumstances may definitely lead to state-of-the-art treatments delivered to patients. The most important practical recommendations are: choosing syringes with as little silicone oil as possible, or, preferably, none; avoiding agitation of syringes; awareness that most biologics (e.g., antiangiogenic proteins) are susceptible to changes in molecular properties under some conditions, such as agitation and temperature variation; understanding that improper materials and techniques may lead to complications after intravitreal injections, e.g., inflammation; and recognizing that some devices may contribute to an enhanced, safer, and faster intravitreal injection technique.

Silicone Oil Particles in Prefilled Syringes With Human Monoclonal Antibody, Representative of Real-World Drug Products, Did Not Increase Immunogenicity in In Vivo and In Vitro Model Systems

Silicone oil is a lubricant for prefilled syringes (PFS), a common primary container for biotherapeutics. Silicone oil particles (SiOP) shed from PFS are a concern for patients due to their potential for increased immunogenicity and therefore also of regulatory concern. To address the safety concern in a context of manufacturing and distribution of drug product (DP), SiOP was increased (up to ∼25,000 particles/mL) in PFS filled with mAb1, a fully human antibody drug, by simulated handling of DP mimicked by drop shock. These samples are characterized in a companion report (Jiao N et al. J Pharm Sci. 2020). The risk of immunogenicity was then assessed using in vitro and in vivo immune model systems. The impact of a common DP excipient, polysorbate 80, on both the formation and biological consequences of SiOP was also tested. SiOP was found associated with (1) minimal cytokine secretion from human peripheral blood mononuclear cells, (2) no response in cell lines that report NF-κB/AP-1 signaling, and (3) no antidrug antibodies or significant cytokine production in transgenic Xeno-het mice, whether or not mAb1 or polysorbate 80 was present. These results suggest that SiOP in mAb1, representative of real-world DP in PFS, poses no increased risk of immunogenicity.

DEHP Nanodroplets Leached From Polyvinyl Chloride IV Bags Promote Aggregation of IVIG and Activate Complement in Human Serum

Concerns regarding the impact of subvisible particulate impurities on the safety and efficacy of therapeutic protein products have led manufacturers to implement strategies to minimize protein aggregation and particle formation during manufacturing, storage, and shipping. However, once these products are released, manufacturers have limited control over product handling. In this work, we investigated the effect of di(2-ethylhexyl) phthalate (DEHP) nanodroplets generated in polyvinyl chloride (PVC) bags of intravenous (IV) saline on the stability and immunogenicity of IV immunoglobulin (IVIG) formulations. We showed that PVC IV bags containing saline can release DEHP droplets into the solution when agitated or transported using a pneumatic tube transportation system in a clinical setting. We next investigated the effects of emulsified DEHP nanodroplets on IVIG stability and immunogenicity. IVIG adsorbed strongly to DEHP nanodroplets, forming a monolayer. In addition, DEHP nanodroplets accelerated IVIG aggregation in agitated samples. The immunogenicity of DEHP nanodroplets and IVIG aggregates generated in these formulations were evaluated using an in vitro assay of complement activation in human serum. The results suggested DEHP nanodroplets shed from PVC IV bags could reduce protein stability and induce activation of the complement system, potentially contributing to adverse immune responses during the administration of therapeutic proteins.

How Full-Length FVIII Benefits from Its Heterogeneity - Insights into the Role of the B-Domain

Purpose

To explore how the natural heterogeneity of human coagulation factor VIII (FVIII) and the processing of its B-domain specifically modulate protein aggregation.

Methods

Recombinant FVIII (rFVIII) molecular species containing 70% or 20% B-domain, and B-domain-deleted rFVIII (BDD-rFVIII), were separated from full-length recombinant FVIII (FL-rFVIII). Purified human plasma-derived FVIII (pdFVIII) was used as a comparator. Heterogeneity and aggregation of the various rFVIII molecular species, FL-rFVIII and pdFVIII were analysed by SDS-PAGE, dynamic light scattering, high-performance size-exclusion chromatography and flow cytometry-based particle analysis.

Results

FL-rFVIII and pdFVIII were heterogeneous in nature and demonstrated similar resistance to aggregation under physical stress. Differences were observed between these and among rFVIII molecular species. FVIII molecular species exhibited diverging aggregation pathways dependent on B-domain content. The propensity to form aggregates increased with decreasing proportions of B-domain, whereas the opposite was observed for oligomer formation. Development of cross-β sheet-containing aggregates in BDD-rFVIII induced effective homologous seeding and faster aggregation. Naturally heterogeneous FL-rFVIII and pdFVIII displayed the lowest propensity to aggregate in all experiments.

Conclusions

These results demonstrate that pdFVIII and FL-rFVIII have similar levels of molecular heterogeneity, and suggest that heterogeneity and the B-domain are involved in stabilising FVIII by modulating its aggregation pathway.

Electronic supplementary material

The online version of this article (10.1007/s11095-019-2599-2) contains supplementary material, which is available to authorized users.

Intact bioactivities and improved pharmacokinetic of the SL335-IFN-β-1a fusion protein that created by genetic fusion of SL335, a human anti-serum albumin fab, and human interferon-β

Recombinant human interferon beta (rIFN-β) has long been used as a first-line treatment for multiple sclerosis (MS), and any attempt to develop a long-acting rIFN-β is desirable since only one pegylated version of long-acting rIFN-β-1a (Plegridy) is currently available in clinics. Previously, we reported that SL335, a human Fab molecule specific to serum albumin, exhibits an extended serum half-life via utilizing the FcRn recycling mechanism. With the ultimate goal of developing a long-acting rIFN-®, we generated a fusion construct by linking human IFN-β cDNA to the C-terminus of the SL335 H chain at the DNA level followed by expression of the fusion protein, referred to as SL335-IFN-β-1a, in Chinese hamster ovary-S (CHO-S) cells. In its N-linked glycosylated form, the resulting fusion protein was easily purified from the culture supernatant via a three-step chromatography process. In vitro functional assays revealed that the fusion protein retained its intrinsic binding capabilities to human serum albumin (HSA) and interferon α/β receptor (IFNAR) that were almost identical to those of parental SL335 and rIFN-β-1a (Rebif). In addition, the fusion protein possessed an antiviral potency and anti-proliferation activity comparable to those of Rebif. In pharmacokinetic (PK) analyses using Lewis rats and cynomolgus monkeys, SL335-IFN-β-1a exhibited at least a two-fold longer serum half-life and a significantly reduced renal clearance rate compared to those of Rebif. Finally, a four-week repeated dose toxicity study revealed no abnormal toxicological signs. In conclusion, our results clearly demonstrated that SL335-IFN-β-1a is worthy of further development as an alternative long-acting IFN-β therapeutic.

Effect of Chemical Oxidation on the Higher Order Structure, Stability, Aggregation, and Biological Function of Interferon Alpha-2a: Role of Local Structural Changes Detected by 2D NMR

PURPOSE

Oxidized interferons have been shown to aggregate and cause immunogenicity. In this study, the structural mechanisms underlying oxidation-induced interferon alpha-2a (IFNA2a) aggregation and loss of function were examined.

METHODS

IFNA2a was oxidized using 0.037% vol/vol hydrogen peroxide. Oxidized protein was probed using biophysical methods that include denaturant melts, particle counting, proteolysis-coupled mass spectrometry, and 2D NMR.

RESULTS

Oxidized IFNA2a did not show major changes in its secondary structure, but showed minor changes in tertiary structure when compared to the unoxidized protein. In addition, a significant loss of conformational stability was observed upon oxidation. Correspondingly, increased protein aggregation was observed resulting in the formation of sub-visible particles. Oxidized protein showed decreased biological function in terms of its anti-viral potency and cytopathic inhibition efficacy. Proteolysis-coupled mass spectrometry identified five methionine residues that were oxidized with no correlation between the extent of oxidation and their accessible surface area. 2D ¹⁵N-¹H HSQC NMR identified residue-level local structural changes in the protein upon oxidation, which were not detectable by global probes such as far-UV circular dichroism and fluorescence.

CONCLUSIONS

Increased protein aggregation and decreased function of IFNA2a upon oxidation correlated with the site of modification identified by proteolysis-coupled mass spectrometry and local structural changes in the protein detected by 2D NMR.

Expanding Bedside Filtration-A Powerful Tool to Protect Patients From Protein Aggregates

Protein immunogenicity is intensively researched by academics, biopharmaceutical companies, and authorities as it can compromise the safety and efficacy of a biopharmaceutical drug. So far, the exact protein aggregate properties inducing immune responses are not known. Possible protein-related factors could be size, chemical modifications, or higher order structures. It is impossible to achieve an absolute absence of protein aggregates even for very stable formulations. The application of "bedside filtration," meaning filtration during the preparation or administration of the drug product immediately before injection, has the potential to increase the safety of every drug container and could prevent the undesired injection of particulate matter into the patient. In this study, the high efficiency of filtration for reducing the amount of protein particles was demonstrated with more than 19 stressed and nonstressed biopharmaceutical products which covered a broad concentration and molecular weight range. Furthermore, critical aspects regarding the usage of filters such as particle shedding from filters, protein loss as a result of protein adsorption, or the hold-up volume of the filters were assessed. Although differences between the filters were observed, no negative impact by the investigated filters could be found. A broader application of bedside filtration is therefore proposed.

Submicron Size Particles of a Murine Monoclonal Antibody Are More Immunogenic Than Soluble Oligomers or Micron Size Particles Upon Subcutaneous Administration in Mice

Protein aggregates are one of the several risk factors for undesired immunogenicity of biopharmaceuticals. However, it remains unclear which features determine whether aggregates will trigger an unwanted immune response. The aim of this study was to determine the effect of aggregates' size on their relative immunogenicity. A monoclonal murine IgG1 was stressed by exposure to low pH and elevated temperature followed by stirring to obtain aggregates widely differing in size. Aggregate fractions enriched in soluble oligomers, submicron size particles and micron size particles were isolated via centrifugation or size-exclusion chromatography and characterized physicochemically. The secondary and tertiary structures of aggregates were altered in a similar way for all the fractions, while no substantial chemical degradation was observed. Development of anti-drug antibodies was measured after subcutaneous administration of each enriched fraction to BALB/c mice. Among all tested fractions, the most immunogenic was the one highly enriched in submicron size particles (∼100-1000 nm). Fractions composed of micron size (>1-100 μm) particles or soluble oligomers (<100 nm) were not immunogenic under the dosing regimen studied in this work. These results show that aggregate size is an important factor for protein immunogenicity.

Comparative analysis of marketed factor VIII products: recombinant products are not alike vis-a-vis soluble protein aggregates and subvisible particles

Essentials Aggregation is a critical quality attribute of protein therapeutics influencing immunogenicity. Aggregates and subvisible particles in 9 recombinant factor VIII (rFVIII) products were analyzed. Major differences in aggregate and particle concentrations were detected after reconstitution. rFVIII product quality determined aggregation propensity under use-relevant stress.

SUMMARY

Background Recombinant protein technologies have facilitated the development of novel factor VIII (FVIII) therapeutics with improved production efficiency, potency and half-live, and a low risk of viral transmission. The increasing number of recombinant FVIII (rFVIII) products and information on their efficacy, safety and cost allow patients and healthcare professionals to adjust treatment to individual needs. Nonetheless, 20-32% of previously untreated patients with severe hemophilia A develop inhibitory antibodies to rFVIII following treatment. The root cause of the immunogenicity of rFVIII products is not well understood. Data for human interferon and human insulin products suggest that critical quality parameters such as soluble protein aggregates (SPAs) and subvisible particles (SVPs) influence the immunogenicity of protein therapeutics. Therefore, we analyzed SPA and SVP concentrations in commercially available rFVIII products and determined how these parameters change upon exposure of rFVIII products to relevant stress conditions. Objectives Compare critical quality parameters such as SPA and SVP concentrations in rFVIII products under intended use and use-relevant stress conditions. Methods Nine rFVIII products (≥ 3 lots each) were analyzed by high-performance liquid chromatography-size exclusion chromatography (HPLC-SEC) and flow cytometry-based particle analysis. Results/conclusions SPAs and SVPs were present at different concentrations in all freshly reconstituted rFVIII products: SPA concentrations ranged from 0.2% to 11.6%; SVPs were 0.7 × 106 to 114.0 × 106 / 1000 IU. Under use-relevant stress conditions (agitation and shear stress) the products formed additional SPAs and SVPs to different degrees. The collected data indicate that product quality determines its propensity to form SVPs and SPAs, and highlights differences between marketed rFVIII products.

Effect of HLA-DRB1 alleles and genetic variants on the development of neutralizing antibodies to interferon beta in the BEYOND and BENEFIT trials

BACKGROUND

Treatment of multiple sclerosis (MS) with interferon β can lead to the development of antibodies directed against interferon β that interfere with treatment efficacy. Several observational studies have proposed different HLA alleles and genetic variants associated with the development of antibodies against interferon β.

OBJECTIVE

To validate the proposed genetic markers and to identify new markers.

METHODS

Associations of genetic candidate markers with antibody presence and development were examined in a post hoc analysis in 941 patients treated with interferon β-1b in the Betaferon^® Efficacy Yielding Outcomes of a New Dose (BEYOND) and BEtaseron^®/BEtaferon^® in Newly Emerging multiple sclerosis For Initial Treatment (BENEFIT) prospective phase III trials. All patients were treated with interferon β-1b for at least 6 months. In addition, a genome-wide association study was conducted to identify new genetic variants.

RESULTS

We confirmed an increased risk for carriers of HLA-DRB1*04:01 (odds ratio (OR) = 3.3, p = 6.9 × 10^-4) and HLA-DRB1*07:01 (OR = 1.8, p = 3.5 × 10^-3) for developing neutralizing antibodies (NAbs). Several additional, previously proposed HLA alleles and genetic variants showed nominally significant associations. In the exploratory analysis, variants in the HLA region were associated with NAb development at genome-wide significance (OR = 2.6, p = 2.30 × 10^-15).

CONCLUSION

The contribution of HLA alleles and HLA-associated single-nucleotide polymorphisms (SNPs) to the development and titer of antibodies against interferon β was confirmed in the combined analysis of two multi-national, multi-center studies.

Cell based assay identifies TLR2 and TLR4 stimulating impurities in Interferon beta

Immunogenicity can have devastating consequences on the safety and efficacy of therapeutic proteins. Therefore, evaluating and mitigating the risk of product immunogenicity is critical for the development these products. This study, showed that Betaseron and Extavia, which are reported to be more immunogenic among IFNβ products in clinical usage, contain residual innate immune response modulating impurities (IIRMIs) capable of activating NF-κB and induced expression of inflammatory mediators. These IIRMIs were undetectable in Rebif or Avonex. The stimulatory effect was attributed solely to IIRMIs because it was evident in murine cells lacking the interferon receptor (IFNAR). The IIRMIs in Betaseron and Extavia triggered NF-κB activation in HEK-293 cells bearing TLR2 and TLR4 in MyD88 dependent manner. Importantly, the IIRMIs in Betaseron induced up-regulation of IL-6, IL-1β, and ccl5 in the skin of IFNAR knock out mice following subcutaneous administration. This indicates that trace level IIRMIs in Betaseron could contribute to the higher immunogenicity rates seen in clinics. Together these data suggest that cell based assays can reveal subtle but clinically relevant differences in IIRMIs following manufacturing changes or between products with the same active ingredients but different manufacturing processes. Appreciating these differences may inform immunogenicity risk assessments.

Visual Detection of Denatured Glutathione Peptides: A Facile Method to Visibly Detect Heat Stressed Biomolecules

Every year pharmaceutical companies use significant resources to mitigate aggregation of pharmaceutical drug products. Specifically, peptides and proteins that have been denatured or degraded can lead to adverse patient reactions such as undesired immune responses. Current methods to detect aggregation of biological molecules are limited to costly and time consuming processes such as high pressure liquid chromatography, ultrahigh pressure liquid chromatography and SDS-PAGE gels. Aggregation of pharmaceutical drug products can occur during manufacturing, processing, packaging, shipment and storage. Therefore, a facile in solution detection method was evaluated to visually detect denatured glutathione peptides, utilizing gold nanoparticle aggregation via 3-Aminopropyltreithoxysilane. Glutathione was denatured using a 70 °C water bath to create an accelerated heat stressed environment. The peptide, gold nanoparticle and aminosilane solution was then characterized via, UV-Vis spectroscopy, FTIR spectroscopy, dynamic light scattering and scanning electron microscopy. Captured images and resulting absorbance spectra of the gold nanoparticle, glutathione, and aminosilane complex demonstrated visual color changes detectable with the human eye as a function of the denaturation time. This work serves as an extended proof of concept for fast in solution detection methods for glutathione peptides that have experienced heat stress.

Deciphering the Biophysical Effects of Oxidizing Sulfur-Containing Amino Acids in Interferon-beta-1a using MS and HDX-MS

Introduction of a chemical change to one or more amino acids in a protein's polypeptide chain can result in various effects on its higher-order structure (HOS) and biophysical behavior (or properties). These effects range from no detectable change to significant structural or conformational alteration that can greatly affect the protein's biophysical properties and its resulting biological function. The ability to reliably detect the absence or presence of such changes is essential to understanding the structure-function relationship in a protein and in the successful commercial development of protein-based drugs (biopharmaceuticals). In this paper, we focus our attention on the latter by specifically elucidating the impact of oxidation on the HOS, structural dynamics, and biophysical properties of interferon beta-1a (IFNβ-1a). Oxidation is a common biochemical modification that occurs in many biopharmaceuticals, specifically in two naturally-occurring sulfur-containing amino acids, methionine and cysteine. To carry out this work, we used combinations of hydrogen peroxide and pH to differentially oxidize IFNβ-1a (to focus on only methionine oxidation versus methionine and cysteine oxidation). We then employed several analytical and biophysical techniques to acquire information about the differential impact of these two oxidation scenarios on IFNβ-1a. In particular, the use of MS-based techniques, especially HDX-MS, play a dominant role in revealing the differential effects. Graphical Abstract ᅟ.

Use of In Vitro Assays to Assess Immunogenicity Risk of Antibody-Based Biotherapeutics

An In Vitro Comparative Immunogenicity Assessment (IVCIA) assay was evaluated as a tool for predicting the potential relative immunogenicity of biotherapeutic attributes. Peripheral blood mononuclear cells from up to 50 healthy naïve human donors were monitored up to 8 days for T-cell proliferation, the number of IL-2 or IFN-γ secreting cells, and the concentration of a panel of secreted cytokines. The response in the assay to 10 monoclonal antibodies was found to be in agreement with the clinical immunogenicity, suggesting that the assay might be applied to immunogenicity risk assessment of antibody biotherapeutic attributes. However, the response in the assay is a measure of T-cell functional activity and the alignment with clinical immunogenicity depends on several other factors. The assay was sensitive to sequence variants and could differentiate single point mutations of the same biotherapeutic. Nine mAbs that were highly aggregated by stirring induced a higher response in the assay than the original mAbs before stirring stress, in a manner that did not match the relative T-cell response of the original mAbs. In contrast, mAbs that were glycated by different sugars (galactose, glucose, and mannose) showed little to no increase in response in the assay above the response to the original mAbs before glycation treatment. The assay was also used successfully to assess similarity between multiple lots of the same mAb, both from the same manufacturer and from different manufacturers (biosimilars). A strategy for using the IVCIA assay for immunogenicity risk assessment during the entire lifespan development of biopharmaceuticals is proposed.