l-Proline reduces IgG dimer content and enhances the stability of intravenous immunoglobulin (IVIG) solutions

Comparative effectiveness of two intravenous immunoglobulin products in children with Kawasaki disease, a nationwide cohort study

Kawasaki Disease (KD) is the most common acquired pediatric heart disease in the developed world. Rapid infusion of high-dose intravenous immunoglobulin is the standard therapy. Different manufacturing processes of IVIG may influence their efficacy. This study aims to conduct a head to head comparison of two IVIGs, TBSF and Privigen, from a nationwide perspective. The main data source was the National Health Insurance Research Database (NHIRD) of Taiwan. A total of 3368 KD cases involving children under 2 years of age were enrolled from January 2015 to November 2020. The primary endpoint was IVIG resistance, which we defined as the total amount exceeding 26 g in one admission. The secondary endpoints encompassed two distinct criteria: coronary involvement, which was defined as the prolonged use of aspirin or anti-coagulation agents between 180 and 360 days after the index date, and recurrence, which was defined as readmission for IVIG therapy occurring more than 30 days after previous KD index day and continuing until the end of the follow-up period. Privigen demonstrated a lower IVIG resistance rate at 9.4% in comparison to TBSF, which exhibited a rate of 9.7% (odds ratio 0.72, 95% CI 0.52-0.99). Privigen had a lower odds of coronary involvement (odds ratio 0.38, 95% CI 0.18-0.82). There is no difference in recurrence rate (odds ratio 0.60, 95% CI 0.22-1.68). Privigen might have a lower rate of IVIG resistance and reduced coronary artery involvement. The discrepancy may be due to the concentration, the stabilizers, or the source of plasma. Further investigation is needed to compare the effectiveness of different IVIGs in the large randomized controlled clinical trial.

An investigation of excipients for a stable Orf viral vector formulation

The Orf virus (ORFV) is a promising candidate for vector vaccines as well as for immunomodulatory and oncolytic therapies. However, few publications are available on its infectivity degradation or on suitable additives for prolonging its viral stability. In this study, the non-supplemented ORFV itself showed a very high stability at storage temperatures up to 28 °C, with a linear titer loss of 0.10 log infectious particles per day at 4 °C over a period of five weeks. To prolong this inherent stability, thirty additives, i.e., detergents, sugars, proteins, salts, and buffers as well as amino acids, were tested for their time- and temperature-dependent influence on the ORFV infectivity. A stabilizing effect on the infectivity was identified for the addition of all tested proteins, i.e., gelatine, bovine serum albumin, and recombinant human serum albumin (rHSA), of several sugars, i.e., mannitol, galactose, sucrose, and trehalose, of amino acids, i.e., arginine and proline, of the detergent Pluronic F68, and of the salt Na2SO4. The infectivity preservation was especially pronounced for proteins in liquid and frozen formulations, sugars in frozen state, and arginine und Pluronic in liquid formulations at high storage temperatures (37 °C). The addition of 1% rHSA with and without 5% sucrose was evaluated as a very stable formulation with a high safety profile and economic validity at storage temperatures up to 28 °C. At increased temperatures, the supplementation with 200 mM arginine performed better than with rHSA. In summary, this comprehensive data provides different options for a stable ORFV formulation, considering temperature, storage time, economic aspects, and downstream processing integrity.

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.

An optimized microplate-based method to evaluate complement-dependent hemolysis mediated by intravenous immunoglobulins (IVIG)

Hemolytic reactions can cause serious complications after administration of Intravenous Immunoglobulin (IVIG), due to passive transfer of anti-A and anti-B IgG antibodies (isoagglutinins). A maximum allowable amount of isoagglutinins is established in the US and EU for licensed IVIG, as measured by a specified direct hemagglutination test (DHAT). Despite this limit, reports of hemolysis have increased over time, raising the question of how well the DHAT predicts clinically significant hemolysis. This study was undertaken to develop a microplate-based complement-dependent hemolysis assay (CDHA) that reproducibly measures functional hemolytic activity of IVIG, for assessment of IVIG products. An IVIG working reference reagent (NIBSC 14/160) was qualified as an assay control and for quantitation purposes. Hemolytic activities of 36 IVIG product lots encompassing seven brands and including 6 clinically hemolytic lots were measured. Hemolytic activity varied among IVIG product brands, and to a lesser extent, from lot-to-lot for individual brands. Correlation between the CDHA and DHAT was not robust which may reflect imprecision of the DHAT method or additional variables that influence complement-dependent hemolysis after opsonization. In conclusion, the CDHA provides a simple, specific, and sensitive tool for IVIG product characterization and investigation of hemolytic events by manufacturers, researchers, and regulatory authorities.

Polypseudorotaxane-based supramolecular hydrogels consisting of cyclodextrins and Pluronics as stabilizing agents for antibody drugs

Recently, antibody drugs have been used worldwide, and based on worldwide sales, 7 of the top 10 pharmaceutical products in 2019 were antibody-based drugs. However, antibody drugs often form aggregates upon thermal and shaking stresses with few efficient stabilizing agents against both stresses. Herein, we developed polypseudorotaxane (PpRX) hydrogels consisting of cyclodextrins (CyDs) and polyethylene glycol (PEG)-polypropylene glycol (PPG)-PEG block copolymers (Pluronics F108, F87, F68, and L44), and evaluated their utility as antibody stabilizing agents. α- and γ-CyDs formed PpRX hydrogels with Pluronics, where CyD/F108 gels showed remarkable stabilizing effects for human immunoglobulin G (IgG) against both thermal and shaking stresses beyond CyD/PEG gels or generic gels. The effects were probably due to the interaction between IgG and the free PPG block of Pluronic F108, resulting in the strong IgG retention in the gels. These findings suggest the great potential of CyD/Pluronic gels as pharmaceutical materials for antibody formulations.

Product-Specific Impact of Viscosity Modulating Formulation Excipients During Ultra-High Concentration Biotherapeutics Drug Product Development

Developing ultra-high concentration biotherapeutics drug products can be challenging due to increased viscosity, processing, and stability issues. Excipients used to alleviate these concerns are traditionally evaluated at lower protein concentrations. This study investigates whether classically known modulators of stability and viscosity at low (<50 mg/mL) to high (>50 - 150 mg/mL) protein concentrations are beneficial in ultra-high (>150 mg/mL) concentration protein formulations and drug products. This study evaluates the effect of arginine monohydrochloride, proline, and lysine monohydrochloride on viscosity and concentratability at different high and ultra-high protein concentrations using a monoclonal antibody, mAbN, formulation as a candidate protein system. The effect of excipients on the viscosity and concentratability (rate and extent) was different at high versus ultra-high protein concentrations. These results highlight that classical excipients in literature known to modulate protein interactions at low protein concentrations and reduce viscosity at high protein concentrations may need to be evaluated at target protein concentrations in a product-specific manner while developing ultra-high concentration biologics drug products.

Dissecting the mechanism of action of intravenous immunoglobulin in human autoimmune disease: Lessons from therapeutic modalities targeting Fcγ receptors

Since the first description of the administration of high doses of pooled serum IgG, also referred to as intravenous IgG (IVIg) therapy, as being able to ameliorate various autoimmune diseases, researchers have been investigating which molecular and cellular pathways underlie IVIg activity. Apart from trying to understand the obvious conundrum that IgG can trigger both autoimmune pathology and resolution of inflammation, the rapidly expanding use of IVIg has led to a lack of availability of this primary blood product, providing a strong rationale for developing recombinant alternatives. During the last decade, a tremendous number of novel insights into IVIg activity brought the goal of replacing IVIg within reach, at least in select indications, and has led to the initiation of several clinical trials. At the forefront of this effort is the modulation of autoantibody half-life and blocking access of autoantibodies to fragment cystallizable γ receptors (Fcγ receptors). In this rostrum article, we will briefly discuss current models of IVIg activity, followed by a more specific focus on novel therapeutic avenues that are entering the clinic and may replace IVIg in the future.

Pharmacokinetic properties of Privigen® in Japanese patients with primary immunodeficiency

This prospective, Phase 3, open-label, study (EudraCT: 2016-001631-12) evaluated pharmacokinetic (PK) characteristics of 3-/4-weekly Privigen^® (IgPro10, CSL Behring, King of Prussia, PA, USA) in Japanese patients with PID. PK parameters including serum trough immunoglobulin (IgG) level before next infusion during the wash-in/wash-out phase (C_trough), area under the concentration-time curve from time point zero to the last time point with quantifiable concentration (AUC_0-last), dose-adjusted AUC_0-last (dAUC), lowest and highest observed IgG levels (C_min, C_max), time to reach C_max (T_max), and total clearance (CL) were analyzed for both regimens of Privigen^® (dose: 138-554 mg/kg body weight). Ten patients were included in this analysis (3-/4-weekly: n = 2/n = 8). C_trough levels achieved ranged 7.96-10.05 g/L. C_max was observed approximately 1 h after the start of the infusion in both regimens. Mean (SD [not applicable for 3-weekly data]) PK parameters: C_max, 16.60 and 14.20 (5.53) g/L; C_min, 10.60 and 8.53 (3.89) g/L; AUC_0-last, 5971 and 6591 (2633) g*h/L; dAUC, 0.41 and 0.46 (0.19) g*h/L/mg; CL, 2.53 and 2.53 (1.00) mL/h and median T_max was 1.19 and 1.14 h, for 3-/4-weekly dosing regimens, respectively. Privigen^® PK characteristics in Japanese patients were similar between dosing regimens and to previously-reported results in non-Japanese patients with PID.

Changes of Serum IgG Dimer Levels after Treatment with IVIg in Guillain-Barré Syndrome

Intravenous immunoglobulins (IVIg) are standard treatment for Guillain-Barré syndrome (GBS). Their exact mechanisms of action are versatile and not fully understood. One possible mechanism is neutralization of circulating autoantibodies via binding to anti- idiotypic antibodies forming idiotype-anti-idiotype dimeric IgG immune complexes. To examine the role of immune complex formation as mechanism of action for IVIg in GBS, 34 C57Bl/6 mice were either treated with anti-ganglioside antibodies and IVIg or IVIg and PBS alone, whereas eight additional mice were treated either with anti-ganglioside autoantibodies and IVIg or anti-ganglioside autoantibodies alone. Subsequently IgG dimer formation was assessed by high performance liquid chromatography (HPLC) and enzyme- linked immunosorbent assay (ELISA). In addition, IgG dimer formation was measured in sera of eight GBS patients who were treated with IVIg. In mice, a significant increase of dimeric IgG after administration of anti-ganglioside antibodies and IVIg could be observed. Re-monomerized IgG dimers showed immunoreactivity against gangliosides and serum immunoreactivity was significantly reduced after IVIg infusion. Likewise also in GBS patients, IgG dimer formation could be detected after IVIg treatment. Our data indicate that dimeric IgG immune complexes contain anti-idiotypic antibodies and provide proof of concept that IVIg treatment in GBS results in measurable amounts of IgG dimers. Larger patient cohorts are needed to evaluate serum IgG dimer increase as a possible marker for treatment response in GBS. Graphical Abstract Mechanism of action: Intravenous immunoglobulins (IVIg) and anti-ganglioside antibodies form dimeric IgG immune complexes, preventing axonal damage in Guillain-Barré Syndrome.

Passive Serum Therapy to Immunomodulation by IVIG: A Fascinating Journey of Antibodies

The immunoregulatory and anti-infective properties of normal circulating polyclonal Abs have been exploited for the therapeutic purposes in the form of IVIG as well as several hyperimmune globulins. Current knowledge on the therapeutic use of normal Igs is based on the discoveries made by several pioneers of the field. In this paper, we review the evolution of IVIG over the years. More importantly, the process started as an s.c. replacement in γ globulin-deficient patients, underwent metamorphosis into i.m. Ig, was followed by IVIG, and is now back to s.c. forms. Following successful use of IVIG in immune thrombocytopenic purpura, there has been an explosion in the therapeutic applications of IVIG in diverse autoimmune and inflammatory conditions. In addition to clinically approved pathological conditions, IVIG has been used as an off-label drug in more than 100 different indications. The current worldwide consumption of IVIG is over 100 tons per year.

Engineered hexavalent Fc proteins with enhanced Fc-gamma receptor avidity provide insights into immune-complex interactions

Autoantibody-mediated diseases are currently treated with intravenous immunoglobulin, which is thought to act in part via blockade of Fc gamma receptors, thereby inhibiting autoantibody effector functions and subsequent pathology. We aimed to develop recombinant molecules with enhanced Fc receptor avidity and thus increased potency over intravenous immunoglobulin. Here we describe the molecular engineering of human Fc hexamers and explore their therapeutic and safety profiles. We show Fc hexamers were more potent than IVIG in phagocytosis blockade and disease models. However, in human whole-blood safety assays incubation with IgG1 isotype Fc hexamers resulted in cytokine release, platelet and complement activation, whereas the IgG4 version did not. We used a statistically designed mutagenesis approach to identify the key Fc residues involved in these processes. Cytokine release was found to be dependent on neutrophil FcγRIIIb interactions with L234 and A327 in the Fc. Therefore, Fc hexamers provide unique insights into Fc receptor biology.

Tania Rowley et al. present multivalent Fc molecules with enhanced avidity for Fc gamma receptors in order to improve the treatment of autoantibody-mediated human diseases. They found several key amino acids involved in Fc receptor binding interactions.

IgPro20, the Polyneuropathy and Treatment with Hizentra® study (PATH), and the treatment of chronic inflammatory demyelinating polyradiculoneuropathy with subcutaneous IgG

Subcutaneous IgG (SCIG) administration may be preferred over the intravenous route (IVIG) in chronic inflammatory demyelinating polyneuropathy (CIDP) because it minimizes ‘end of cycle’ treatment-related fluctuations, reduces systemic adverse effects, improves convenience/quality of life and potentially lowers overall costs. Early reports of the use of highly concentrated SCIG preparations suggested they were effective and well-tolerated in chronic inflammatory demyelinating polyneuropathy. This was confirmed in the Polyneuropathy and Treatment with Hizentra® study of 172 subjects randomized to receive maintenance therapy with placebo or one of two doses of IgPro20 (20% IgG stabilized with L-Proline) for 6 months. Risk of relapse was reduced by SCIG in a dose-related manner as compared with placebo. A total of 88% of polyneuropathy and treatment with hizentra subjects felt the subcutaneous method was ‘easy to learn’. Local adverse events were mostly mild or moderate, and systemic adverse events were infrequent. Some patients may prefer maintenance therapy with SCIG over IVIG.

[Approach for identifying of treatment option for pediatric patients in Guillain-Barre syndrome considering results of pharmacoeconomic analysis]

AIM

A pharmacoeconomic analysis of direct costs on treatment with high dose intravenous immunoglobulins (IVIG) and plasmapheresis (PP) in children.

MATERIAL AND METHODS

Literature data on the pathogenesis of Guillain-Barre syndrome (GBS) were analyzed. The results of pharmacoeconomic analysis of direct costs on treatment of GBS using IVIG and PP are presented. Risks for complications during treatment with IVIG and PP are calculated.

RESULTS AND CONCLUSION

The pharmacoeconomic analysis demonstrates comparable costs of treatment with IVIG or PP in the Russian Federation. Nevertheless, a less number of complications, convenience in use and the good safety and tolerability profile make it more preferable to this group of patients. In a clinical case of a 7-year child described in the article, treatment with 10% IVIG - privigen in dose 2 g/kg during 5 days started in the 3^rd week of disease showed a marked positive effect.

Dimeric IgG complexes from IVIg are incapable of inducing in vitro neutrophil degranulation or complement activation

Purpose

Intravenous immunoglobulin (IVIg) products contain various amounts of dimeric IgG complexes. Current insights into the possible biological activities of these dimers remain controversial, and both immunemodulating and immune-activating effects have been reported. Here, we analyzed the putative immune-activating effects of dimers isolated from IVIg.

Methods

Dimers isolated from IVIg were purified by high-performance size-exclusion chromatography (HP-SEC) and tested for the ability to induce neutrophil degranulation in vitro.

Results

Dimers isolated from IVIg were found to be incapable of inducing in vitro neutrophil degranulation or complement activation, even at concentrations exceeding those expected to be reached upon administration in patients. These results depend on the removal of artefactual activation by using 0.1 micron filtration and the use of poloxamer to prevent adsorption of IgG onto the solid phase.

Conclusions

The data suggest dimeric IgG found in IVIg may bind to Fc-receptors without causing activation.

Effect of IVIG Formulation on IgG Binding to Self- and Exo- Antigens In Vitro and In Vivo

In relation to the recent trials of Intravenous Immunoglobulin (IVIG) in Alzheimer’s Disease (AD) it was demonstrated that different IgG preparations contain varying amounts of natural anti-amyloid β (Aβ) antibodies as measured by ELISA. We therefore investigated the relevance of ELISA data for measuring low-affinity antibodies, such as anti-Aβ. We analysed the binding of different commercial Immunoglobulin G (IgG) preparations to Aβ, actin and tetanus toxoid in different binding assays to further investigate the possible cause for observed differences in binding to Aβ and actin between different IgG preparations. We show that the differences of commercial IgG preparations in binding to Aβ and actin in ELISA assays are artefactual and only evident in in vitro binding assays. In functional assays and in vivo animal studies the different IVIG preparations exhibited very similar potency. ELISA data alone are not appropriate to analyse and rank the binding capacity of low-affinity antibodies to Aβ or other endogenous self-antigens contained in IgG preparations. Additional analytical methods should be adopted to complement ELISA data.

Design and Evaluation of the Highly Concentrated Human IgG Formulation Using Cyclodextrin Polypseudorotaxane Hydrogels

To achieve the potent therapeutic effects of human immunoglobulin G (IgG), highly concentrated formulations are required. However, the stabilization for highly concentrated human IgG is laborious work. In the present study, to investigate the potentials of polypseudorotaxane (PPRX) hydrogels consisting of polyethylene glycol (PEG) and α- or γ-cyclodextrin (α- or γ-CyD) as pharmaceutical materials for highly concentrated human IgG, we designed the PPRX hydrogels including human IgG and evaluated their pharmaceutical properties. The α- and γ-CyDs formed PPRX hydrogels with PEG (M.W. 20,000) even in the presence of highly concentrated human IgG (>100 mg/mL). According to the results of (1)H-NMR, powder X-ray diffraction, and Raman microscopy, the formation of human IgG/CyD PPRX hydrogels was based on physical cross-linking arising from their columnar structures. The release profiles of human IgG from the hydrogels were in accordance with the non-Fickian diffusion model. Importantly, the stabilities of human IgG included into the hydrogels against thermal and shaking stresses were markedly improved. These findings suggest that PEG/CyD PPRX hydrogels are useful to prepare the formulation for highly concentrated human IgG.

[Intravenous immunoglobulin in treatment of autoimmune neurological diseases in children]

Though the mechanisms of action of intravenous immunoglobulins (IVIG) are not completely understood, these drugs are widely used in treatment of autoimmune diseases. In this review, we have analyzed the literature on the use of IVIG in the treatment of autoimmune diseases of the nervous system in children and discuss the management of patients basing on the recommendation of the European Federation of Neurological Societies. The efficacy of IVIG in children has been shown as first line treatment in Guillain-Barre syndrome, chronic inflammatory demyelinating polyneuropathy, multifocal motor neuropathy, dermatomyositis as a second-line drug in the combination with prednisolone or immunosuppressors in patients refractory to treatment with corticosteroids and cytostatics, myasthenic crisis in myasthenia gravis, exacerbations and short-term treatment of severe forms, non-responsiveness to acetylcholinesterase inhibitors, multiple sclerosis as second or third line of treatment in patients with relapsing-remitting course with intolerance to standard immunomodulatory therapy, acute multiple encephalomyelitis with no response to the treatment with high doses of corticosteroids, paraneoplastic syndromes, pharmacoresistant epilepsy and autoimmune encephalitis. Because the right choice of the drug plays a key role, in particular, in children, that determines the efficacy and safety of the treatment, we present the main approaches to the choice of the drug and schemes of treatment of autoimmune diseases of the nervous system in children.

Efficacy and tolerability of 16% subcutaneous immunoglobulin compared with 20% subcutaneous immunoglobulin in primary antibody deficiency

Multiple subcutaneous immunoglobulin (SCIG) products are available to treat primary antibody deficiency (PAD). The efficacy and tolerability of 16% SCIG (Vivaglobin(®) ) was compared with 20% SCIG (Hizentra(®) ) in PAD subjects. The study was a prospective, single-centre, open-label study of PAD subjects transitioning Vivaglobin to equivalent Hizentra doses, rounded to the nearest vial size. Comparisons included immunoglobulin (Ig)G levels; tetanus, varicella and Streptococcus pneumoniae titres; adverse events (AEs), annual infection rate and quality of life during 8 weeks of Vivaglobin and 24 weeks of Hizentra. Thirty-two subjects (aged 2-75 years) participated. Rounding to the nearest Hizentra vial size resulted in a 12·8% (± 2·9%) increase in SCIG dose. Median immunoglobulin (Ig)G level following 8 weeks of Vivaglobin was similar to 24 weeks of Hizentra (1050 versus 1035 mg/dl, respectively; P = 0·77). Both products had similar protective titres to tetanus, varicella and serotypes of S. pneumoniae, which were variable but well above protective levels. After 12 weeks of Hizentra, subjects reported fewer local site reactions compared with Vivaglobin. Switching products resulted in increased systemic AEs in some subjects but, overall, not significantly higher than during Vivaglobin treatment. Average infusion time decreased from 104·7 min (3·3 sites) with Vivaglobin to 70·7 min (2·2 sites) with Hizentra (P = 0·0005). Acute serious bacterial infections were similar. Treatment satisfaction was superior with Hizentra. Hizentra and Vivaglobin have similar pharmacokinetics and efficacy. Although transition to a different SCIG product initially increased AEs, Hizentra is well tolerated and can be infused more rapidly and with fewer sites compared to Vivaglobin.

Chronic inflammatory demyelinating polyneuropathy (CIDP): change of serum IgG dimer levels during treatment with intravenous immunoglobulins

Background

Intravenous immunoglobulin (IVIg) is an effective treatment in chronic inflammatory demyelinating polyneuropathy (CIDP). In most patients, the optimal IVIg dose and regime is unknown. Polyvalent immunoglobulin (Ig) G form idiotypic/anti-idiotypic antibody pairs in serum and IVIg preparations. We determined IgG dimer levels before and after IVIg treatment in CIDP patients with the aim to explore their utility to serve as a surrogate marker for treatment response.

Methods

IgG was purified from serum of five controls without treatment, as well as from serum of 16 CIDP patients, two patients with Miller Fisher syndrome (MFS), and one patient with myasthenia gravis before and after treatment with IVIg. IgG dimer levels were determined by size exclusion chromatography. IgG dimer formation was correlated with clinical response to IVIg treatment in CIDP. Re-monomerized IgG dimer fractions were analyzed for immunoreactivity against peripheral nerve tissue.

Results

IgG dimer levels were significantly higher in post- compared to pre-IVIg infusion samples. Low post-treatment IgG dimer levels in CIDP patients were associated with clinical worsening during IVIg treatment. Re-monomerized IgG dimer fractions from CIDP patients showed immunoreactivity against peripheral nerve tissue, whereas similarly treated samples from MFS patients showed immunoreactivity against GQ1b.

Conclusion

Assessment of IgG dimer levels could be a novel approach to monitor CIDP patients during IVIg treatment, but further studies in larger cohorts are warranted to explore their utility to serve as a potential therapeutic biomarker for IVIg treatment response in CIDP.

Probing structurally altered and aggregated states of therapeutically relevant proteins using GroEL coupled to bio-layer interferometry

The ability of a GroEL-based bio-layer interferometry (BLI) assay to detect structurally altered and/or aggregated species of pharmaceutically relevant proteins is demonstrated. Assay development included optimizing biotinylated-GroEL immobilization to streptavidin biosensors, combined with biophysical and activity measurements showing native and biotinylated GroEL are both stable and active. First, acidic fibroblast growth factor (FGF-1) was incubated under conditions known to promote (40°C) and inhibit (heparin addition) molten globule formation. Heat exposed (40°C) FGF-1 exhibited binding to GroEL-biosensors, which was significantly diminished in the presence of heparin. Second, a polyclonal human IgG solution containing 6-8% non-native dimer showed an increase in higher molecular weight aggregates upon heating by size exclusion chromatography (SEC). The poly IgG solution displayed binding to GroEL-biosensors initially with progressively increased binding upon heating. Enriched preparations of the IgG dimers or monomers showed significant binding to GroEL-biosensors. Finally, a thermally treated IgG1 monoclonal antibody (mAb) solution also demonstrated increased GroEL-biosensor binding, but with different kinetics. The bound complexes could be partially to fully dissociated after ATP addition (i.e., specific GroEL binding) depending on the protein, environmental stress, and the assay's experimental conditions. Transmission electron microscopy (TEM) images of GroEL-mAb complexes, released from the biosensor, also confirmed interaction of bound complexes at the GroEL binding site with heat-stressed mAb. Results indicate that the GroEL-biosensor-BLI method can detect conformationally altered and/or early aggregation states of proteins, and may potentially be useful as a rapid, stability-indicating biosensor assay for monitoring the structural integrity and physical stability of therapeutic protein candidates.

Effective protocol for the investigation of physicochemical and conformational stability and aggregation kinetics measurements of therapeutic IgG2 monoclonal antibody

Characterisation of monoclonal antibodies (mAbs) represents an ongoing challenge due to their diverse 3-dimensional structures that can affect their stability, immunogenicity and/or toxicity. Although circular dichroism (CD) spectroscopy provides rapid determinations of protein secondary structure in solutions, there is a pressing need for an improvement in current practices in applying the technique for batch QC. There is a lack of experimental evidence in the literature which is concerned with improving the current practices. This work is based on an effective protocol for the study of IgG2a stability in solution using the simultaneous measurements of absorbance, turbidity and CD. A novel approach has been developed for the study of the effects of pH and additives with minimum protein shock that may cause premature aggregation and deceptive results. A computer programme has been designed for the rapid and simultaneous analysis of aggregation during UV and CD measurements, also, highlighting instrumental variations. Temperature stability determination, elucidation of unfolding pathways and aggregation kinetics were estimated with accuracy. This experimental approach provides important information about mAbs physicochemical and conformational stability, helps distinguish between unfolded, refolded, aggregated, and flocculated states and is an excellent tool in the development of therapeutic antibodies.

Effect of osmolytes on the fibrillation of HypF-N

We have studied the effect of a series of stabilizing and destabilizing osmolytes on the fibrillation pattern of a model amyloidogenic protein, HypF-N. Under mildly denaturing conditions, HypF-N forms cross β-sheet structures, characteristic of amyloid fibrils. In the presence of all stabilizing osmolytes except proline, fibrillation of HypF-N is inhibited. Notably, fibrillation kinetics is retarded at subdenaturing concentrations of chaotropes. In case of proline, fibrillation of HypF-N is accelerated. Thus, the changes during exposure of a protein to denaturing conditions in the presence of osmolyes cannot be extrapolated from their role as anti-fibrillation agents.

Identification of aggregation breakers for bevacizumab (Avastin®) self-association through similarity searching and interaction studies

Aggregation is a common challenge in the optimization of therapeutic antibody formulations. Since initial self-association of two monomers is typically a reversible process, the aim of this study is to identify different excipients that are able to shift this equilibrium to the monomeric state. The hypothesis is that a specific interaction between excipient and antibody may hinder two monomers from approaching each other, based on previous work in which dexamethasone phosphate showed the ability to partially reverse formed aggregates of the monoclonal IgG1 antibody bevacizumab back into monomers. The current study focuses on the selection of therapeutically inactive compounds with similar properties. Adenosine monophosphate, adenosine triphosphate, sucrose-6-phosphate and guanosine monophosphate were selected in silico through similarity searching and docking. All four compounds were predicted to bind to a protein-protein interaction hotspot on the Fc region of bevacizumab and thereby breaking dimer formation. The predictions were supported in vitro: An interaction between AMP and bevacizumab with a dissociation constant of 9.59±0.15 mM was observed by microscale thermophoresis. The stability of the antibody at elevated temperature (40 °C) in a 51 mM phosphate buffer pH 7 was investigated in presence and absence of the excipients. Quantification of the different aggregation species by asymmetrical flow field-flow fractionation and size exclusion chromatography demonstrates that all four excipients are able to partially overcome the initial self-association of bevacizumab monomers.

Comparison of Intravenous Immunoglobulin Formulations: Product Formulary, and Cost Considerations

Purpose

A review of the different formulations of intravenous immunoglobulin (IVIG) replacement therapy for primary immunodeficiency and other severe diseases, focusing on the comparative efficacy, safety, and tolerability of these formulations. This review discusses the manufacturing processes, physicochemical properties, and other attributes of IVIG therapy that affect its clinical utility.

Summary

IVIG therapy is a preferred treatment for patients with certain types of primary immunodeficiency, neuroimmunologic, and autoimmune hematologic disorders, as well as for immunomodulation in bone marrow and some solid organ transplants. The IVIG products available in the United States include lyophilized, 5% liquid, and 10% ready-to-use liquid formulations. Differences among these formulations in their manufacturing processes, excipients, pH, and physicochemical properties may be reflected as differences in clinical efficacy, safety, and tolerability. For example, compared with lyophilized and 5% liquid IVIG formulations, 10% ready-to-use IVIG liquid formulations may be associated with better tolerability because of lower IgA concentrations, optimal pH, use of glycine or proline stabilizers, low sodium content, and less osmolality. Liquid formulations (both 5% and 10%) may provide greater convenience than lyophilized formulations for both patients and health care providers, because they do not require further dilution before administration and have shorter infusion times.

Conclusion

Before selecting an IVIG product for a hospital formulary, pharmacists should be knowledgeable about the product's concentration to ensure delivery of the proper dosage, the staff training needed for proper administration, the potential benefits and problems of brand substitution, the safety and efficacy of each formulation, the hospital's policies on off-label use of IVIG, and the impact of reimbursement.

Aggregation factor analysis for protein formulation by a systematic approach using FTIR, SEC and design of experiments techniques

A simple systematic approach using Fourier transform infrared (FTIR) spectroscopy, size exclusion chromatography (SEC) and design of experiments (DOE) techniques was applied to the analysis of aggregation factors for protein formulations in stress and accelerated testings. FTIR and SEC were used to evaluate protein conformational and storage stabilities, respectively. DOE was used to determine the suitable formulation and to analyze both the main effect of single factors and the interaction effect of combined factors on aggregation. Our results indicated that (i) analysis at a low protein concentration is not always applicable to high concentration formulations; (ii) an investigation of interaction effects of combined factors as well as main effects of single factors is effective for improving conformational stability of proteins; (iii) with the exception of pH, the results of stress testing with regard to aggregation factors would be available for suitable formulation instead of performing time-consuming accelerated testing; (iv) a suitable pH condition should not be determined in stress testing but in accelerated testing, because of inconsistent effects of pH on conformational and storage stabilities. In summary, we propose a three-step strategy, using FTIR, SEC and DOE techniques, to effectively analyze the aggregation factors and perform a rapid screening for suitable conditions of protein formulation.

Subcutaneous immunoglobulin replacement therapy with Hizentra, the first 20% SCIG preparation: a practical approach

To reduce the risk of infection in adults and children with primary immunodeficiencies, replacement therapy with IgG, which can be administered to patients intravenously or subcutaneously, is required. Although intravenous administration of IgG (IVIG) has been the therapy of choice in the US and widely used in Europe for many years, subcutaneous administration of IgG (SCIG) has recently gained considerable acceptance among patients and doctors. SCIG therapy achieves high and stable serum IgG levels, is well tolerated, and can be self-administered. Hizentra (IgPro20; CSL Behring, Berne, Switzerland) is the first, ready-to-use 20% liquid preparation of human IgG specifically formulated for subcutaneous infusions. The high concentration (20%) might allow shorter infusion times due to smaller infusion volumes, with potential improvement in the convenience of SCIG therapy. Hizentra is well tolerated and has been shown to protect adult and pediatric primary immunodeficiency patients against serious bacterial infections. In addition, it is easy to handle and can be stored at a temperature up to 25°C. In summary, Hizentra is an advance in the field of immunoglobulin replacement therapy, which might offer benefits for home therapy patients.

L-proline-stabilized human IgG: Privigen® 10% for intravenous use and Hizentra® 20% for subcutaneous use

Liquid IgG preparations are preferred over lyophilized preparations because reconstitution is not required. Formation of dimers and aggregates in liquid preparations increases adverse effects and limits the shelf life of most liquid IgG products. Improved understanding of the binding interactions in IgG dimers and aggregates led to the selection of L-proline at pH 4.8 as an excipient that would minimize their formation. CSL Behring has developed the L-proline-stabilized products Privigen®, a 10% IgG solution for intravenous use; and Hizentra®, a 20% solution for subcutaneous use. The former has the longest shelf life of any liquid IgG in the USA--36 months, and the latter is the most concentrated IgG available. These improvements, which translate into improved convenience for pharmacies and patients, were achieved with no compromise in safety, efficacy or tolerability of the products.

Interactions between immunoglobulin G molecules

Immune globulin preparations such as intravenous immunoglobulin (IVIG) and monoclonal antibodies are widely used in clinics as effective therapeutic agents for the treatment of a number of autoimmune diseases, cancer, inflammations and other pathologies. Significant amounts of IgG aggregates have been found in the highly concentrated solutions of therapeutic immune proteins. The IgG self-aggregation that appears especially after prolonged storage increases the immunogenicity of the preparations and also modifies their physical properties, first of all producing the high viscosity. The attractive IgG-IgG interactions pose a significant problem for the clinical usage of the immune proteins. During last decades intensive studies of the IgG self-association were performed. The presence of IgG dimers was demonstrated in pooled preparations. These complexes are the result of idiotype-anti-idiotype interactions. In concentrated solutions of immune globulins and monoclonal antibodies self-associated IgG molecules formed a network, increasing the viscosity. The forces responsible for the IgG association are characteristic of the protein-protein interactions in general. The amino acid residues of the Fab and Fc portions participate in the IgG-IgG contacts. Recently contact residues were modified by the site-directed mutagenesis in order to decrease the formation of the IgG self-aggregates. The mutant IgG antibodies were characterized by enhanced stability as compared with the non-modified antibody molecules. Peptic pFc' fragment and the C(H)3 domain were shown to be capable of interacting with Fc regions, thus preventing IgG aggregation. In perspective both approaches could improve the formulation of immune globulin preparations. Removal of IgG aggregates could be achieved by chromatography on hydroxyapatite.

Tolerability of a new 10% liquid immunoglobulin for intravenous use, Privigen, at different infusion rates

PURPOSE

The tolerability of L-proline-stabilized Privigen, a new 10% liquid immunoglobulin for intravenous administration, was assessed at high infusion rates in a Phase III, open-label, single-arm, multicenter study in 45 patients with primary immune deficiencies.

PATIENTS AND METHODS

Maximum infusion rates were not assigned prospectively. For analysis, patients were grouped according to maximum infusion rate in a low infusion rate group (8 mg/kg/min) and high infusion rate group (12 mg/kg/min).

RESULTS

Twenty-three patients, selected at the investigators' discretion for the high infusion rate group based on their good tolerability, tolerated Privigen at 12 mg/kg/min with no increase in temporally associated adverse events (AEs) above the level they had experienced at 8 mg/kg/min. The proportion of infusions with temporally associated AEs in these patients was 0.079 [97.5% confidence interval (CI) 0.114] compared to 0.211 (97.5% CI 0.267) in the low infusion rate group. The most frequent AE was headache. Thus, selected patients tolerate Privigen at high infusion rates.