Subvisible Particles in IVIg Formulations Activate Complement in Human Serum

Utilizing A hydrophobic primary container surface to reduce the formation of subvisible particles in monoclonal antibody solution caused by fluid shear

The exposure of protein molecules to interfaces may cause protein aggregation and particle formation in protein formulations, especially hydrophobic interfaces, which may promote protein aggregation in solution. In this study, we found that modification of the surface properties by application of a hydrophobic Octadecyltrichlorosilane (OTS) could reduce the generation of protein aggregates and particles in protein solution induced by fluid shear. A stable protein adsorption layer was formed at the hydrophobic interface through the strong hydrophobic interaction between the protein and hydrophobic surface, which could prevent the aggregated protein from falling off into the bulk solution to form subvisible particles and insoluble protein aggregates. In addition, human complement enzyme linked immunosorbent assay results showed that the particles that were generated in the OTS-coated container did not activate human complement which indicated the OTS-coated container could be used as primary containers for certain types of monoclonal antibody formulation.

Submicron immunoglobulin particles exhibit FcγRII-dependent toxicity linked to autophagy in TNFα-stimulated endothelial cells

In intravenous immunoglobulins (IVIG), and some other immunoglobulin products, protein particles have been implicated in adverse events. Role and mechanisms of immunoglobulin particles in vascular adverse effects of blood components and manufactured biologics have not been elucidated. We have developed a model of spherical silica microparticles (SiMPs) of distinct sizes 200-2000 nm coated with different IVIG- or albumin (HSA)-coronas and investigated their effects on cultured human umbilical vein endothelial cells (HUVEC). IVIG products (1-20 mg/mL), bare SiMPs or SiMPs with IVIG-corona, did not display significant toxicity to unstimulated HUVEC. In contrast, in TNFα-stimulated HUVEC, IVIG-SiMPs induced decrease of HUVEC viability compared to HSA-SiMPs, while no toxicity of soluble IVIG was observed. 200 nm IVIG-SiMPs after 24 h treatment further increased ICAM1 (intercellular adhesion molecule 1) and tissue factor surface expression, apoptosis, mammalian target of rapamacin (mTOR)-dependent activation of autophagy, and release of extracellular vesicles, positive for mitophagy markers. Toxic effects of IVIG-SiMPs were most prominent for 200 nm SiMPs and decreased with larger SiMP size. Using blocking antibodies, toxicity of IVIG-SiMPs was found dependent on FcγRII receptor expression on HUVEC, which increased after TNFα-stimulation. Similar results were observed with different IVIG products and research grade IgG preparations. In conclusion, submicron particles with immunoglobulin corona induced size-dependent toxicity in TNFα-stimulated HUVEC via FcγRII receptors, associated with apoptosis and mTOR-dependent activation of autophagy. Testing of IVIG toxicity in endothelial cells prestimulated with proinflammatory cytokines is relevant to clinical conditions. Our results warrant further studies on endothelial toxicity of sub-visible immunoglobulin particles.

Biochemical Characterization of a New 10% IVIG Preparation [IgG Next Generation (BT595)/Yimmugo®] Obtained from a Manufacturing Process Preserving IgA/IgM Potential of Human Plasma

BACKGROUND AND OBJECTIVE

Human plasma is used for the generation of several life-saving drugs and contains valuable antibodies from the immunoglobulin classes IgG, IgM and IgA. Purified intravenous IgG solutions (IVIGs) form the majority of plasma-derived medicine to treat patients with various forms of immunodeficiencies. In conventional IVIG manufacturing processes, immunoglobulin classes IgM and IgA are often discarded as contaminants, but these antibody classes have been proven to be effective for the treatment of acute bacterial infections. Considering the increase in demand for human plasma-derived products and the ethical value of the raw material, a more resource-saving usage of human plasma is needed. Intensive research over the last decades showed that adverse reactions to IVIGs depend on the presence of thrombogenic factors, partially unfolded proteins, non-specific activation of the complement system, and blood group specific antibodies. Therefore, new IVIG preparations with reduced risks of adverse reactions are desirable.

METHOD

A new manufacturing process that yields two biologics was established and quality attributes of the new IVIG solution (Yimmugo®) obtained from this process are presented.

RESULTS

Here, we provide a biochemical characterization of Yimmugo®, a new 10% IVIG preparation. It is derived from human blood plasma by a combined manufacturing process, where IgM and IgA are retained for the production of a new biologic (trimodulin, currently under investigation in phase III clinical trials). Several improvements have been implemented in the manufacturing of Yimmugo® to reduce the risk of adverse reactions. Gentle and efficient mixing by vibration (called "vibromixing") during a process step where proteins are at risk to aggregate was implemented to potentially minimize protein damage. In addition, a dedicated process step for the removal of the complement system activator properdin was implemented, which resulted in very low anticomplementary activity levels. The absence of measurable thrombogenic activity in combination with a very high degree of functional monomeric antibodies predict excellent efficacy and tolerability.

CONCLUSION

Yimmugo® constitutes a new high quality IVIG preparation derived from a novel manufacturing process that takes advantage of the full therapeutic immunoglobulin potential of human plasma.

Nanoparticulate impurities in the pharmaceutical excipient trehalose induce an early immune response

BACKGROUND

Pharmaceutical excipients are an important part of biological products. However, few attempts have been made to distinguish between the risk of inflammation associated with the biological products themselves and that associated with excipients. The analysis of early immune response risk associated with excipients added to biological products is an important step in exploring the complex mechanism of side effects in susceptible patients.

METHODS AND RESULTS

In this study, nanoparticle impurities (NPIs) were extracted from trehalose and characterized. A mouse popliteal lymph node cell (PLNA) model, a mouse spleen lymphocyte model, a human peripheral blood mononuclear cell cytokine release model, and a macrophage complement activation model were established to comprehensively evaluate the early immune risk related to impurities in the trehalose excipient. Although popliteal lymph node cell counts in mice did not show significant differences, all other models indicated possible immune risk. In the PLNA model, NPIs caused significant toe thickening in mice, whereby the content of IgE and MCP-1 increased significantly. NPIs significantly increased the proliferation and differentiation of spleen lymphocytes according to the CCK-8 assay and flow cytometry. After treatment with NPIs, the release of IgE and a variety of cytokines (MIP-1α, IFN-γ, IL-2, IL-8, TNF-α, IL-6, IL-1α) in human peripheral blood cells was significantly increased according to ELISA, while a concomitant increase of C3a/C5a as well as C4a/Bb proved that NPIs activated the complement system.

CONCLUSION

NPIs from trehalose elicited an immune response in vitro, and the immune response to trehalose may be related to NPIs and not the excipient itself. Different batches of trehalose showed different immune response effects. The currents research suggests that when trehalose is applied in high-risk administration routes, NPIs should be assessed and reasonably controlled.

Immunogenicity Risk Assessment of Spontaneously Occurring Therapeutic Monoclonal Antibody Aggregates

Aggregates of therapeutic proteins have been associated with increased immunogenicity in pre-clinical models as well as in human patients. Recent studies to understand aggregates and their immunogenicity risks use artificial stress methods to induce high levels of aggregation. These methods may be less biologically relevant in terms of their quantity than those that occur spontaneously during processing and storage. Here we describe the immunogenicity risk due to spontaneously occurring therapeutic antibody aggregates using peripheral blood mononuclear cells (PBMC) and a cell line with a reporter gene for immune activation: THP-1 BLUE NFκB. The spontaneously occurring therapeutic protein aggregates were obtained from process intermediates and final formulated drug substance from stability retains. Spontaneously occurring aggregates elicited innate immune responses for several donors in a PBMC assay with cytokine and chemokine production as a readout for immune activation. Meanwhile, no significant adaptive phase responses to spontaneously occurring aggregate samples were detected. While the THP-1 BLUE NFκB cell line and PBMC assays both responded to high stress induced aggregates, only the PBMC from a limited subset of donors responded to processing-induced aggregates. In this case study, levels of antibody aggregation occurring at process relevant levels are lower than those induced by stirring and may pose lower risk in vivo. Our methodologies can further inform additional immunogenicity risk assessments using a pre-clinical in vitro risk assessment approach utilizing human derived immune cells.

Modulating Nanoparticle Size to Understand Factors Affecting Hemostatic Efficacy and Maximize Survival in a Lethal Inferior Vena Cava Injury Model

Intravenous nanoparticle hemostats offer a potentially attractive approach to promote hemostasis, in particular for inaccessible wounds such as noncompressible torso hemorrhage (NCTH). In this work, particle size was tuned over a range of <100-500 nm, and its effect on nanoparticle-platelet interactions was systematically assessed using in vitro and in vivo experiments. Smaller particles bound a larger percentage of platelets per mass of particle delivered, while larger particles resulted in higher particle accumulation on a surface of platelets and collagen. Intermediate particles led to the greatest platelet content in platelet-nanoparticle aggregates, indicating that they may be able to recruit more platelets to the wound. In biodistribution studies, smaller and intermediate nanoparticles exhibited longer circulation lifetimes, while larger nanoparticles resulted in higher pulmonary accumulation. The particles were then challenged in a 2 h lethal inferior vena cava (IVC) puncture model, where intermediate nanoparticles significantly increased both survival and injury-specific targeting relative to saline and unfunctionalized particle controls. An increase in survival in the second hour was likewise observed in the smaller nanoparticles relative to saline controls, though no significant increase in survival was observed in the larger nanoparticle size. In conjunction with prior in vitro and in vivo experiments, these results suggest that platelet content in aggregates and extended nanoparticle circulation lifetimes are instrumental to enhancing hemostasis. Ultimately, this study elucidates the role of particle size in platelet-particle interactions, which can be a useful tool for engineering the performance of particulate hemostats and improving the design of these materials.

Machine Learning and Accelerated Stress Approaches to Differentiate Potential Causes of Aggregation in Polyclonal Antibody Formulations During Shipping

Therapeutic proteins are among the most widely prescribed medications, with wide distribution and complex supply chains. Shipping exposes protein formulations to stresses that can trigger aggregation, although the exact mechanism(s) responsible for aggregation are unknown. To better understand how shipping causes aggregation, we compared populations of aggregates that were formed in a polyclonal antibody formulation during live shipping studies to populations observed in accelerated stability studies designed to mimic both the sporadic high g-force and continuous low g-force stresses encountered during shipping. Additionally, we compared the effects on aggregation levels generated in two types of secondary packaging, one of which was designed to mitigate the effects of large g-force stresses. Aggregation was quantified using fluorescence intensity of 4,4'-dianilino-1,1'-binaphthyl-5,5'-disulfonic acid (bis-ANS) dye, size exclusion high performance liquid chromatography (SECHPLC), and flow imaging microscopy (FIM). FIM was also combined with machine learning methods to analyze particle morphology distributions. These comparisons revealed that the morphology distributions of aggregates formed during live shipping resemble distributions that result from low g-force events, but not those observed following high g-force events, suggesting that low g-force stresses play a predominant role in shipping-induced aggregation.