Subcutaneous immunoglobulin infusion: a new therapeutic option in chronic inflammatory demyelinating polyneuropathy

A review of intravenous immunoglobulin in the treatment of neuroimmune conditions, acute COVID-19 infection, and post-acute sequelae of COVID-19 Syndrome

Intravenous immunoglobulin (IVIG) is an immunomodulatory therapy that has been studied in several neuroimmune conditions, such as Guillain-Barré Syndrome, chronic inflammatory demyelinating polyneuropathy, multifocal motor neuropathy, and multiple sclerosis. It has also been proposed as a potential treatment option for acute COVID-19 infection and post-acute sequelae of SARS-CoV-2 infection (PASC). IVIG is thought to function by providing the recipient with a pool of antibodies, which can, in turn, modulate immune responses through multiple mechanisms including neutralization of cytokines and autoantibodies, saturation of neonatal fragment crystallizable receptors, inhibition of complement activation, and regulation of T and B cell mediated inflammation. In acute COVID-19, studies have shown that early administration of IVIG and plasmapheresis in severe cases can reduce the need for mechanical ventilation, shorten ICU and hospital stays, and lower mortality. Similarly, in PASC, while research is still in early stages, IVIG has been shown to alleviate persistent symptoms in small patient cohorts. Furthermore, IVIG has shown benefits in another condition which has symptomatic overlap with PASC, myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), though studies have yielded mixed results. It is important to note that IVIG can be associated with several potential adverse effects, such as anaphylaxis, headaches, thrombosis, liver enzyme elevations and renal complications. In addition, the high cost of IVIG can be a deterrent for payers and patients. This review provides a comprehensive update on the use of IVIG in multiple neuroimmune conditions, ME/CFS, acute COVID-19, and PASC, as well as covers its history, production, pricing, and mechanisms of action. We also identify key areas of future research, including the need to optimize the use of Ig product dosing, timing, and patient selection across conditions, particularly in the context of COVID-19 and PASC.

Subcutaneous immunoglobulins (SCIG) for chronic inflammatory demyelinating polyneuropathy (CIDP): A comprehensive systematic review of clinical studies and meta-analysis

BACKGROUND

Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) presents significant treatment challenges due to its chronic nature, varied clinical presentations, and rarity. Subcutaneous immunoglobulin (SCIG) has emerged as a maintenance therapy, offering potential advantages in administration and patient experience over the previously recognized intravenous immunoglobulin (IVIG).

METHODS

We included all clinical studies involving CIDP patients treated with SCIG from eleven databases up to March 2024.

RESULTS

50 clinical studies were included in the systematic review, with 22 involved in the meta-analysis. These studies offer clinical data on around 1400 CIDP patients. Almost all studies considered SCIG a maintenance therapy, with the majority of results suggesting it as a viable substitute that may offer comparable or enhanced advantages. Studies covered aspects such as efficacy, safety, quality of life, practicality, economic evaluation, and patient preference. Meta-analysis showed SCIG significantly improved muscle strength and sensory function, had fewer and milder side effects, reduced relapse rates, and received a strong preference.

CONCLUSIONS

Findings suggest that SCIG for CIDP maintenance not only provides a more feasible alternative, with economic evaluations showing considerable cost reductions over time, and patient preference for SCIG being pronounced, but may also deliver comparable or superior health outcomes. Ongoing research lines on formulations, techniques, and direct comparative studies are critical to further illuminate, enhance, and expand SCIG's role in treatment.

Subcutaneous Immunoglobulin in Chronic Inflammatory Demyelinating Polyneuropathy: A Historical Perspective

The therapeutic administration of subcutaneous immunoglobulin (SCIg) offers various advantages over intravenous immunoglobulin (IVIg). This narrative review examines and compares SCIg versus IVIg in chronic inflammatory demyelinating polyneuropathy (CIDP). SCIg is as effective as IVIg but is better tolerated and easier to administer, as intravenous access is not required. Furthermore, SCIg administration is more convenient and cost-effective than IVIg, enabling flexible treatment scheduling at home and improving patients' overall quality of life. The availability of highly concentrated immunoglobulin G (IgG) subcutaneous solutions, such as IgPro20, a 20% IgG solution stabilized with L-proline, allows for the administration of larger volumes in a single session, while the parallel development of new technological devices enables the delivery of higher doses over a shorter time. Based on the results of the PATH study, SCIg has become a well-established therapy in CIDP. In addition to discussing the advantages of SCIg, this review summarizes the evolution of SCIg by discussing all the relevant clinical studies which have considered its use in the treatment of CIDP.

Subcutaneous immunoglobulin treatment for chronic inflammatory demyelinating polyneuropathy

Immunoglobulin G (IgG) therapy is an established long‐term treatment in chronic inflammatory demyelinating polyneuropathy (CIDP) that is commonly administered intravenously (IVIg). The subcutaneous immunoglobulin (SCIg) administration route is a safe and effective alternative option, approved by the United States Food and Drug Administration (FDA) in 2018, for maintenance treatment of adults with CIDP. Physicians and patients alike need to be aware of all their treatment options in order to make informed decisions and plan long‐term treatment strategies. In this review, we collate the evidence for SCIg in CIDP from all published studies and discuss their implications and translation to clinical practice. We also provide guidance on the practicalities of how and when to transition patients from IVIg to SCIg and ongoing patient support. Evidence suggests that IVIg and SCIg have comparable long‐term efficacy in CIDP. However, SCIg can provide additional benefits for some patients, including no requirement for venous access or premedication, and reduced frequency of systemic adverse events. Local‐site reactions are more common with SCIg than IVIg, but these are mostly well‐tolerated and abate with subsequent infusions. Data suggest that many patients prefer SCIg following transition from IVIg. SCIg preference may be a result of the independence and flexibility associated with self‐infusion, whereas IVIg preference may be a result of familiarity and reliance on a healthcare professional for infusions. In practice, individualizing maintenance dosing based on disease behavior and determining the minimally effective IgG dose for individuals are key considerations irrespective of the administration route chosen.

Impact of subcutaneous immunoglobulin on quality of life in patients with chronic inflammatory demyelinating polyneuropathy previously treated with intravenous immunoglobulin

INTRODUCTION/AIMS

Intravenous immunoglobulin (IVIg) is a common therapy for patients with chronic inflammatory demyelinating polyneuropathy (CIDP). IVIg may cause systemic adverse events (AEs); therefore, infusion of subcutaneous immunoglobulin (SCIg) may be preferred by some patients. In this study we document the experiences of patients transitioning from IVIg to SCIg.

METHODS

Transitioning subjects with CIDP were followed in a 6-month prospective, open-label study. The primary endpoint was percentage of subjects who withdrew for any reason (including significant AEs). The secondary endpoint was symptom progression or relapse requiring a change in management. Quality of life (QOL) and treatment satisfaction were assessed using the Short Form 36-item Health Survey (SF-36), Treatment Satisfaction Questionnaire for Medication (TSQM), and Chronic Acquired Polyneuropathy Patient-Reported Index (CAP-PRI). Efficacy was assessed using the Inflammatory Rasch-built Overall Disability Scale, hand-held dynamometry, limb motor strength testing (LMST), and timed 25-ft walk (T25-FW).

RESULTS

Fifteen CIDP subjects transitioned from IVIg to SCIg. Of these, three (20%) met the primary endpoint and one (7%) met the secondary endpoint. The SF-36 showed a statistically significant improvement for the domain of role limitations-physical after 24 weeks (P = .03), with no significant differences observed in other domains. TSQM and CAP-PRI showed significant differences in favor of SCIg (P = .003 and .02, respectively). No significant differences were observed in efficacy after 24 weeks, except for LMST, which favored SCIg (P = .003). Eight of the 12 study completers (67%) continued with SCIg.

DISCUSSION

Transition to SCIg was associated with maintained efficacy and improved QOL.

Longer-term effects of intravenous immunoglobulin treatment in chronic inflammatory demyelinating polyneuropathy: Who benefits?

Intravenous immunoglobulins (IVIg) represent an established cornerstone for the immunotherapy of chronic inflammatory demyelinating polyneuropathy (CIDP). Efficacy of IVIg for CIDP was proven in a large phase III trial. Yet, data on longer-term efficacy and effects in distinct subgroups are scarce. Our trial investigates the long-term efficacy of IVIg treatment in CIDP patients. In this observational real-world study, we retrospectively analyzed 49 CIDP patients receiving continuous IVIg treatment with a mean initial dosage of 87 g (1 g/kg body weight) every 4 weeks over a mean time of 45 months between 2010 and 2018. INCAT-Scores before the start of treatment and at the end of the observation period were compared. Over the observation period, IVIg treatment led to a median improvement of one INCAT score point. Subgroup analyses revealed a more pronounced improvement of INCAT scores in female CIDP patients, individuals with relapsing disease courses, patients with more pronounced motor impairment (higher initial INCAT scores) and in the cohort without need for concomitant other immunotherapies. These data argue for sustained beneficial effects of longer-term immunotherapy with IVIg in CIDP, particularly in females and relapsing disease forms with higher disease activity.

Immunoglobulin Treatment in Neuromuscular Medicine

Intravenous immunoglobulin (IVIg) is used in the treatment of autoimmune diseases, including immune-mediated central and peripheral nervous system disorders. This article will review the indications, proposed mechanism of actions, and administration of immunoglobulin treatment in various neuropathies, neuromuscular junction disorders, and myopathies. IVIg may have more than one mechanism of action to alter the pathogenesis of underlying neuromuscular disease. IVIg treatment has been used as a first-line treatment in Guillain-Barre syndrome, chronic inflammatory demyelinating polyradiculoneuropathy, multifocal motor neuropathy, and second-line off-label treatment in medically refractory cases of polymyositis, dermatomyositis, and myasthenia gravis. IVIg is a well-tolerated and effective treatment for these neuromuscular diseases. With this review article, we hope to increase clinicians' awareness of the indications and efficiencies of IVIg in a broad spectrum of neuromuscular diseases.

Comparisons in fluctuation of muscle strength and function in patients with immune-mediated neuropathy treated with intravenous versus subcutaneous immunoglobulin

INTRODUCTION

Variations in muscle strength and function have not been studied in patients with chronic inflammatory demyelinating polyneuropathy and multifocal motor neuropathy whose treatment regimen has been changed from intravenous to subcutaneous immunoglobulin (IVIg to SCIg).

METHODS

In a prospective, open-label study, patients were changed from monthly IVIg to weekly SCIg. The primary endpoint was variation in isokinetic muscle strength (cIKS). Secondary endpoints were variations in Medical Research Council (MRC) score, grip strength (GS), 9-hole-peg test (9-HPT), and 40-meter-walk test (40-MWT).

RESULTS

The coefficient of variance of cIKS during the IVIg and SCIg treatment periods was unchanged (mean ± SD: 6.97 ± 4.83% vs. 5.50 ± 3.13%, P = 0.21). The variations in the 9-HPT and 40-MWT were significantly lower in the SCIg group (P = 0.01 and P = 0.005, respectively).

DISCUSSION

When therapy was changed from IVIg to SCIg, fluctuation of muscle strength was unchanged, but performance fluctuations were diminished. Muscle Nerve 57: 610-614, 2018.

Subcutaneous immunoglobulin treatment in CIDP and MMN. Efficacy, treatment satisfaction and costs

Subcutaneous administration of immunoglobulin (SCIG) in chronic inflammatory demyelinating polyneuropathy (CIDP) and multifocal motor neuropathy (MMN) has been reported in several case reports and in a few randomized trials during the last decade. In this review we present the studies on SCIG in CIDP and MMN with special focus on the clinical effects. Moreover, the effect on quality of life, side effects to SCIG and the health economic perspectives are reviewed. Nine case studies, three randomized trials and six long-term, follow-up studies were identified. Most of the studies are conducted in patients switched from regular IVIG to SCIG treatment; one study involves treatment-naïve patients. The review shows that none of the studies have been powered to demonstrate an effect on disability. SCIG can maintain muscle strength for a period of 1 to 2years and ability seems preserved for a similar period. Quality of life is generally unchanged or improved after switch to SCIG and generalized side-effects seem fewer, whereas local reactions at the injection site occur. Health economic analyses favour SCIG at the doses used in the reviewed studies.

Update on the use of immunoglobulin in human disease: A review of evidence

Human immunoglobulin preparations for intravenous or subcutaneous administration are the cornerstone of treatment in patients with primary immunodeficiency diseases affecting the humoral immune system. Intravenous preparations have a number of important uses in the treatment of other diseases in humans as well, some for which acceptable treatment alternatives do not exist. We provide an update of the evidence-based guideline on immunoglobulin therapy, last published in 2006. Given the potential risks and inherent scarcity of human immunoglobulin, careful consideration of its indications and administration is warranted.

A new treatment regimen with high-dose and fractioned immunoglobulin in a special subgroup of severe and dependent CIDP patients

BACKGROUND

Chronic inflammatory demyelinating polyneuropathy (CIDP) is treated with intravenous immunoglobulins (IVIg), corticosteroids or plasma exchange (PE). IVIg dosage is not universal and markers for treatment management are needed.

METHODS

We report the response to high-dose and fractioned IVIg in a subgroup of definite CIDP patients, resistant to corticosteroids and PE, responders to IVIg but with an efficacy window <15 d.

RESULTS

Four patients were included with similar predominantly clinical motor form and conduction abnormalities. Treatment management consisted of fractioning IVIg and increasing the monthly cumulated dose (mean: 3 g/kg/month). Serum IgG concentration was measured and correlated to the clinical state. Monitoring of serum IgG helped to guide IVIg administration dosage and frequency. A mean of 10 months was required to improve symptoms; therapy was then switched to subcutaneous (SC) route (maintenance dose: 3.5 g/kg/month). The mean Overall Neuropathy Limitations Scale was improved from 11 to 3.2 and the mean Medical Research Council scale from 26 to 90.

CONCLUSION

It is important to distinguish patients with short IVIg efficacy window from those with classical resistance since the former may benefit from fractioning and increasing the IVIg dose. The monitoring of serum IgG level and its correlation to the clinical response could be of help in monitoring each individual's dosage.

Safety and Efficacy of Subcutaneous Immunoglobulin in the Treatment of Neuromuscular Disorders

Many neuromuscular diseases may be treated with immunoglobulins. In the United States, the major form of immunoglobulin used is intravenous (IV). Recently, there has been an increased interest in research regarding the use of subcutaneous immunoglobulin (SCIg), mainly for improved patient quality of life, convenience, potential for fewer systemic adverse events, and avoiding wear-off. The widespread use of the subcutaneous formulation in neurology has been affected by some limitations, mainly the smaller volume and higher frequency of infusions compared to IV administration. Also, there are different pharmacokinetic properties that should be considered to evaluate whether they change the immunomodulatory effect. There are several formulations available that address some limitations. Several studies have assessed efficacy, safety, and quality of life of SCIg in neurology. This review article summarizes the current evidence for the use of SCIg in neuromuscular diseases. It also addresses the pharmacokinetic differences and the different formulations available. The current available preliminary evidence indicates that SCIg is at least as effective as the IV formulations.

Subcutaneous Immunoglobulin Therapy in the Chronic Management of Myasthenia Gravis: A Retrospective Cohort Study

BACKGROUND

Immunoglobulin therapy has become a major treatment option in several autoimmune neuromuscular disorders. For patients with Myasthenia Gravis (MG), intravenous immunoglobulin (IVIg) has been used for both crisis and chronic management. Subcutaneous Immunoglobulins (SCIg), which offer the advantage of home administration, may be a practical and effective option in chronic management of MG. We analyzed clinical outcomes and patient satisfaction in nine cases of chronic disabling MG who were either transitioned to, or started de novo on SCIg.

METHODS AND FINDINGS

This was a retrospective cohort study for the period of 2015-2016, with a mean follow-up period of 6.8 months after initiation of SCIg. All patients with MG treated with SCIg at the Ottawa Hospital, a large Canadian tertiary hospital with subspecialty expertise in neuromuscular disorders were included, regardless of MG severity, clinical subtype and antibody status. The primary outcome was MG disease activity after SCIg initiation. This outcome was measured by 1) the Myasthenia Gravis Foundation of America (MGFA) clinical classification, and 2) subjective scales of disease activity including the Myasthenia Gravis activities of daily living profile (MG-ADL), Myasthenia Gravis Quality-of-life (MG-QOL 15), Visual Analog (VA) satisfaction scale. We also assessed any requirement for emergency department visits or hospitalizations. Safety outcomes included any SCIg related complication. All patients were stable or improved for MGFA class after SCIg initiation. Statistically significant improvements were documented in the MG-ADL, MG-QOL and VAS scales. There were no exacerbations after switching therapy and no severe SCIg related complications.

CONCLUSIONS

SCIg may be a beneficial therapy in the chronic management of MG, with favorable clinical outcome and patient satisfaction results.

Subcutaneous immunoglobulin for maintenance treatment in chronic inflammatory demyelinating polyneuropathy (The PATH Study): study protocol for a randomized controlled trial

BACKGROUND

Subcutaneous administration of Ig (SCIg) has gained popularity as an alternative route of administration but has never been rigorously examined in chronic inflammatory demyelinating polyneuropathy (CIDP).

METHODS/DESIGN

The primary objective of the PATH study (Polyneuropathy and Treatment with Hizentra) is to determine the efficacy of two different doses of SCIg IgPro20 (0.2 g/kg bw or 0.4 g/kg bw) in a 24-week maintenance treatment of CIDP in comparison to placebo. The primary efficacy endpoint will be the proportion of patients who show CIDP relapse (1-point deterioration on the adjusted Inflammatory Neuropathy Cause and Treatment (INCAT) disability score) or are withdrawn within 24 weeks after randomization for any reason. IVIg-dependent adult patients with definite or probable CIDP according to the European Federation of Neurological Societies/Peripheral Nerve Society who fulfil the inclusion and exclusion criteria will be eligible. Based on sample-size calculation and relapse assumptions in the three arms, a sample size of 58 is needed per arm (overall sample size will be 350, of which 174 will be randomized). All eligible patients will progress through three study periods: an IgG dependency period (≤12 weeks) to select those who are Ig dependent; an IVIg restabilization period (10 or 13 weeks), which will be performed using the 10 % IgPro10 product; and an SC treatment period (24 weeks, followed by a 1-week completion visit after last follow-up). Patients showing IVIg restabilization will be randomized to demonstrate the efficacy of SCIg IgPro20 maintenance treatment over placebo. After completing the study, subjects are eligible to enter a long-term, open-label, extension study of 1 year or return to their previous treatment. In case of CIDP relapse during the 24-week SC treatment period, IgPro10 rescue medication will be offered. Safety, tolerability, and patients' preference of Ig administration route will be examined.

DISCUSSION

The PATH trial, which started in March 2012, is expected to finish at the end of 2016. The results will increase knowledge about the efficacy, safety, and tolerability of SCIg in maintenance management of CIDP patients.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT01545076 . Registered on 1 March 2012.

Subcutaneous immunoglobulins in the treatment of chronic immune-mediated neuropathies

Intravenous immunoglobulins represent an established therapy for the treatment of chronic immune-mediated neuropathies, specifically chronic inflammatory demyelinating polyradiculoneuropathies (CIDPs) as well as multifocal motor neuropathies (MMNs). For the treatment of antibody deficiency syndromes, subcutaneous immunoglobulins (SCIgs) have represented a mainstay for decades. An emerging body of evidence suggests that SCIg might also exhibit clinical efficacy in CIDP and MMN. This article reviews the current evidence for clinical effectiveness, as well as safety of SCIg for the treatment of immune-mediated neuropathies, and addresses remaining open questions in this context. We conclude that despite the need for controlled long-term studies to demonstrate long-term efficacy of SCIg in immune-mediated neuropathies, SCIg may already represent a potential therapeutic alternative for selected patients.

Subcutaneous immunoglobulin in treating inflammatory neuromuscular disorders

OBJECTIVE

Intravenous immunoglobulin administration has long been used in the treatment of autoimmune neuromuscular disorders. Immunoglobulins may be administered by intramuscular, intravenous or subcutaneous routes.

METHODS

This is a report on the long-term clinical follow up of six patients with inflammatory neuromuscular disorders, that is, three chronic inflammatory demyelinating polyneuropathy (CIDP), one multifocal motor neuropathy (MMN), one inclusion body myositis (IBM) and one myasthenia gravis (MG), treated with subcutaneous immunoglobulins for a mean of 3.25 years.

RESULTS

One MMN and two CIDP patients received a weekly dose of subcutaneous immunoglobulins equivalent to intravenous immunoglobulin. One CIDP patient received a 50% dose reduction, the IBM patient received a 30% reduction and the MG patient a 20% reduction. The lower dose chosen in the majority of patients was based not only on clinical effects, but also on studies of primary immunodeficiency syndromes. One patient with CIDP showed clinical fluctuation, which was successfully treated with an adaptation of the dose of subcutaneous immunoglobulins, while the remaining patients with neuromuscular disorders had a stable clinical course for 2 years. No serious side effects were observed.

CONCLUSIONS

Our results suggest that subcutaneous immunoglobulins can be an attractive alternative therapy in autoimmune neuromuscular disorders.

New insights into the management of chronic inflammatory demyelinating polyradiculoneuropathy

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and its variants can be challenging to diagnose and treat. A combination of clinical, electrophysiological and laboratory features is often required to reach a diagnosis. New data are emerging about potential biomarkers and factors that may indicate treatment needs in individual patients. High-quality evidence exists for the efficacy of intravenous immunoglobulin (IVIG) in the treatment of CIDP, including quality of life (QoL) benefits. Besides pharmacological treatment, psychological factors must also be addressed to improve patients' QoL. Home-based IVIG infusion therapy is currently a well-established approach in some countries. A 6-month pilot study conducted in Ontario, Canada, provided proof of safety and patient acceptance of home-based IVIG therapy, although some logistical issues emerged.

Optimizing IgG therapy in chronic autoimmune neuropathies: a hypothesis driven approach

Prolonged intravenous immunoglobulin (IVIG) therapy is used for the chronic autoimmune neuropathies chronic idiopathic demyelinating polyneuropathy and multifocal motor neuropathy, but the doses and treatment intervals are usually chosen empirically due to a paucity of data from dose-response studies. Recent studies of the electrophysiology and immunology of these diseases suggest that antibody-induced reversible dysfunction of nodes of Ranvier may play a role in conduction block and disability which responds to immunotherapy more rapidly than would be expected for demyelination or axonal damage per se. Clinical reports suggest that in some cases, the effects of each dose of IVIG may be transient, wearing-off before the next dose is due. These observations lead us to hypothesize that that therapeutic IgG acts by competing with pathologic autoantibodies and that individual patients may require different IgG levels for optimal therapeutic effects. Frequent IVIG dosing and weekly subcutaneous IgG have been tried as ways of continuously maintaining high serum IgG levels, resulting in stabilization of neuromuscular function in small case series. Frequent grip strength and disability measurements, performed by the patient at home and reported electronically, can be used to assess the extent and duration of responses to IgG doses. Individualization of IgG treatment regimens may optimize efficacy, minimize disability, and identify nonresponders.

Is dosing of therapeutic immunoglobulins optimal? A review of a three-decade long debate in europe

The consumption of immunoglobulins (Ig) is increasing due to better recognition of antibody deficiencies, an aging population, and new indications. This review aims to examine the various dosing regimens and research developments in the established and in some of the relevant off-label indications in Europe. The background to the current regulatory settings in Europe is provided as a backdrop for the latest developments in primary and secondary immunodeficiencies and in immunomodulatory indications. In these heterogeneous areas, clinical trials encompassing different routes of administration, varying intervals, and infusion rates are paving the way toward more individualized therapy regimens. In primary antibody deficiencies, adjustments in dosing and intervals will depend on the clinical presentation, effective IgG trough levels and IgG metabolism. Ideally, individual pharmacokinetic profiles in conjunction with the clinical phenotype could lead to highly tailored treatment. In practice, incremental dosage increases are necessary to titrate the optimal dose for more severely ill patients. Higher intravenous doses in these patients also have beneficial immunomodulatory effects beyond mere IgG replacement. Better understanding of the pharmacokinetics of Ig therapy is leading to a move away from simplistic "per kg" dosing. Defective antibody production is common in many secondary immunodeficiencies irrespective of whether the causative factor was lymphoid malignancies (established indications), certain autoimmune disorders, immunosuppressive agents, or biologics. This antibody failure, as shown by test immunization, may be amenable to treatment with replacement Ig therapy. In certain immunomodulatory settings [e.g., idiopathic thrombocytopenic purpura (ITP)], selection of patients for Ig therapy may be enhanced by relevant biomarkers in order to exclude non-responders and thus obtain higher response rates. In this review, the developments in dosing of therapeutic immunoglobulins have been limited to high and some medium priority indications such as ITP, Kawasaki' disease, Guillain-Barré syndrome, chronic inflammatory demyelinating polyradiculoneuropathy, myasthenia gravis, multifocal motor neuropathy, fetal alloimmune thrombocytopenia, fetal hemolytic anemia, and dermatological diseases.

European consensus proposal for immunoglobulin therapies

The use of immunoglobulin (Ig) preparations (intravenous, IVIg, subcutaneous, SCIg) for replacement and immunomodulation therapy worldwide has tripled in the past 20 years and represents an ever-increasing cost factor for healthcare organizations. The limited access to the starting material of this essential medicinal product is currently the driving force for human plasma collection. Increasing awareness and improved diagnosis of human primary immunodeficiencies and a broadening of immunomodulatory indications are responsible for this development, and on a longer run might lead to plasma supply shortages. Consensus recommendations for the optimal use of Ig in clinical practice, including priority rankings for the most urgent indications, are therefore urgently needed. During a recent meeting in Kreuth, Germany, expert nominees from 36 Council of Europe states, together with colleagues from observer countries and regulatory agencies came up with this consensus statement.

Chronic inflammatory demyelinating polyradiculoneuropathy and variants: where we are and where we should go

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a chronic and often disabling sensory motor neuropathy postulated as caused by an immune attack against peripheral nerve myelin. In addition to a classic sensory–motor polyneuropathy, other phenotypes of CIDP have been described including the Lewis- Sumner syndrome, distal acquired demyelinating symmetric (DADS) neuropathy, pure motor CIDP, pure sensory CIDP including chronic immune sensory polyradiculopathy (CISP), and focal CIDP. These phenotypes are currently considered to be variants of CIDP, even if the possibility that they represent different demyelinating neuropathies cannot be fully excluded considering differences in their response to therapy. Several data support the role of the immune system in the pathogenesis of CIDP even if the precise targets and actors (antibodies and lymphocytes) of this immune response remain uncertain. Recent studies have shown that the therapeutic response may differ in patients with peculiar clinical presentations supporting the hypothesis that different pathogenetic mechanisms may underlie the heterogeneity of CIDP. The majority of patients with CIDP show improvement after immune therapies including corticosteroids, plasma exchange, and high-dose intravenous immunoglobulin (IVIg). It remains unclear why none of the other immune therapies that were reported to be variably effective in other immune disorders proved to be effective also in CIDP.

Cost-minimization analysis of IgPro20, a subcutaneous immunoglobulin, in Japanese patients with primary immunodeficiency

PURPOSE

IgPro20, Hizentra(®) an L-proline-stabilized 20% human subcutaneous immunoglobulin (SCIG), has been shown in a Phase III pivotal study to be well tolerated and efficacious in adult and pediatric Japanese patients with primary immunodeficiency. Economic aspects of SCIG treatment in comparison with previous intravenous immunoglobulin (IVIG) therapy were analyzed in this Phase III study in Japan.

METHODS

Twenty-four Japanese patients with primary immunodeficiency on IVIG treatment were switched to IgPro20 at an equivalent dose (full analysis set). The study consisted of a screening period, an IVIG treatment period with 3 planned infusions every 3 or 4 weeks, a 12-week SCIG wash-in and wash-out period, and a 12-week SCIG efficacy period. The difference in medical cost and productivity loss resulting from changes in hospital frequency between the SCIG and IVIG treatment was evaluated. Information about treatment cost was collected as part of the Life Quality Index questionnaire. In addition, productivity loss and hospital-related absenteeism were evaluated.

FINDINGS

Life Quality Index scores for all domains were higher with SCIG than with IVIG in this patient population. In the full analysis set, the mean (SD) Life Quality Index score of the Costs domain increased from 45.1 (26.34) at Week 1 (IVIG period) to 71.9 (18.52) at Week 24 (end of the SCIG efficacy period), representing a mean change of 26.74 and a large score improvement effect size (1.01). Median productivity loss was reduced by 60% from baseline to Weeks 12 and 24. This resulted in a reduction in costs of JPY 10,875 per patient per month at Weeks 12 and 24. Subcutaneous treatment with IgPro20 also reduced hospital-related absenteeism. The number of patients, parents, or guardians who were not absent from work or housework duties and had no reduction in working time increased from 4 (17.4%) at Week 1 to 9 (39.1%) at Week 24. Similar results were obtained in the per-protocol set (n = 21).

IMPLICATIONS

Switching from IVIG to SCIG reduced markedly productivity loss and hospital-related absenteeism. The reduction in hospital visit frequency due to the use of home-based IgG therapy enabled by the change in administration route is expected to produce an important pharmacoeconomic benefit in Japan. Study Code: ZLB06_002CR, ClinicalTrials.gov identifier: NCT01199705.

Hizentra for the treatment of primary immunodeficiency

Immunoglobulin (IgG) replacement therapy has been the cornerstone of treatment for primary immunodeficiency disease for nearly 60 years. During this time, research has continually refined the target IgG trough level and IgG replacement dosages to allow patients with primary immunodeficiency disease to achieve effective protection from infection. Manufacturers have also improved IgG formulations to allow patients to receive clinically beneficial dosages of IgG replacement with improved safety and tolerability. This review will introduce Hizentra(®), a highly concentrated (20%) IgG solution for subcutaneous (sc.) infusion, discuss its manufacturing process and pharmacokinetic profile and review its tolerability and efficacy data as evaluated in clinical trials. New highly concentrated sc. IgG products may improve patient quality of life and adherence to therapy because of the flexible dosing options, fewer infusion sites and less infusion time, compared with less concentrated sc. IgG products, resulting in favorable patient outcomes consistent with higher steady-state IgG levels.

High-dose subcutaneous immunoglobulins for the treatment of severe treatment-resistant polymyositis

Polymyositis is a rare debilitating condition characterized by chronic inflammation and muscle weakness. Standard treatments include corticosteroids and immunosuppressants; however, resistance to these regimens may develop. Intravenous immunoglobulins (IVIg) are thus recommended for patients with drug-resistant polymyositis. The patient presented a resistant polymyositis with severe muscle weakness, increasing dysphagia, and significant loss in weight. Subcutaneous immunoglobulins (SCIg) were initiated after failure of steroids and immunosuppressive drugs. SCIg was given twice per week (2 then 1.3 g/kg/month). Clinical recovery was observed within 2 months after the SCIg initiation. After several injections, the patient showed a progressive improvement in muscle strength. Serum creatine kinase activity decreased to normal levels, and dysphagia was resolved. The SC injections were generally well tolerated and good patient satisfaction was reported. This promising observation suggests that SCIg may be useful in active and refractory polymyositis.

Subcutaneous immunoglobulin therapy for inflammatory neuropathy: current evidence base and future prospects

Intravenous immunoglobulin therapy is of proven effect in chronic inflammatory neuropathies, including chronic inflammatory demyelinating polyneuropathy (CIDP) and multifocal motor neuropathy (MMN). In more recent years, there have been a number of anecdotal case reports and small series, followed by a few trials of variable design, of subcutaneous immunoglobulin therapy in these neuropathies. To date, limited evidence suggests that the subcutaneous route may be a more clinically effective, better-tolerated, at least cost-equivalent and a more patient-friendly option than the still more used intravenous alternative. Long-term efficacy is not as yet established in neuropathic indications by randomised controlled clinical trial evidence, and it is likely that the subcutaneous route may not be suitable in all cases with some hints to this effect appearing from the limited data available to date. Further studies are ongoing, including those of dose comparison, and more are likely to be planned in future. The literature on the use of subcutaneous immunoglobulin therapy in chronic inflammatory neuropathy is reviewed here. The current use in clinical practice, day-to-day benefits, including quality of life measures and health economics as published thus far, are evaluated. The limitations of this form of treatment in CIDP and MMN are also analysed in the light of current literature and taking into account the remaining unknowns. Future prospects and research with this mode of immunoglobulin therapy administration are discussed.

Importance of ancillary supplies for subcutaneous immunoglobulin infusion: management of the local infusion site

A number of ancillary supplies are used in the process of administering subcutaneous immunoglobulin. The particular type of ancillary supplies used (needles, tubing, and tape) may contribute to the development of issues at the local infusion site. Patient case studies demonstrate that changes in the choice of ancillary supplies can often alleviate these issues. The use of alternative ancillary supplies should be considered prior to the possibility of changing immunoglobulin replacement products in patients experiencing local infusion-site issues in order to improve outcomes and increase compliance. A treatment progression algorithm of ancillary supply adjustments has been developed.

Treatment of chronic inflammatory demyelinating polyradiculoneuropathy

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a sporadically occurring, acquired neuropathic condition of autoimmune origin with chronic progressive or relapsing-remitting disease course. CIDP is a treatable disorder; a variety of immunosuppressive and immunomodulatory agents are available to modify, impede, and even reverse the neurological deficits and sequelae that manifest in the course of the disease. However, in many cases CIDP is not curable. Challenges that remain in the treatment of CIDP patients are well recognized and include a remarkably individual heterogeneity in terms of disease course and treatment response as well as a lack of objective and feasible measures to predict and monitor the responsiveness to the available therapies. In this chapter an overview of the currently used drugs in the treatment of CIDP patients is given and some important and controversial issues that arise in the context of care for CIDP patients are discussed.

The expanding role of therapeutic antibodies

Therapeutic antibodies have been used since the end of nineteenth century, but their use is progressively increased and recently, with the availability of monoclonal antibodies, they are successfully employed in a large disease spectrum, which transversally covers different fields of medicine. Hyperimmune polyclonal immune globulin has been used against infectious diseases, in a period in which anti-microbial drugs were not yet available, and it still maintains a relevant place in prophylaxis/therapy. Although immune globulin should be considered life-saving as replacement therapy in humoral immunodeficiencies, its place in the immune-modulating treatment is not usually first-choice, but it should be considered as support to standard approved treatments. Despite therapeutic monoclonal antibodies have been lastly introduced in therapy, their extreme potentiality is reflected by the large number of approved molecules, addressed toward different immunological targets and able to heavily influence the prognosis and quality of life of a wide range of different diseases.

Treatment of chronic inflammatory demyelinating polyneuropathy: from molecular bases to practical considerations

Chronic inflammatory demyelinating polyneuropathy (CIDP) is an autoimmune disease of the peripheral nervous system, in which both cellular and humoral immune responses are involved. The disease is clinically heterogeneous with some patients displaying pure motor form and others also showing a variable degree of sensory dysfunction; disease evolution may also differ from patient to patient, since monophasic, progressive, and relapsing forms are reported. Underlying such clinical variability there is probably a broad spectrum of molecular dysfunctions that are and will be the target of therapeutic strategies. In this review we first explore the biological bases of current treatments and subsequently we focus on the practical management that must also take into account pharmacoeconomic issues.

Home IVIG for CIDP: a focus on patient centred care

OBJECTIVE

To determine the safety and tolerability of home-based intravenous immunoglobulin (IVIG) (Gamunex) as maintenance treatment in patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) in Canada.

METHODS

We enrolled ten subjects with CIDP who had previously received IVIG in the hospital setting to receive the comparable IVIG dose (1-2 g/kg/month) in the home for six months. The patients were evaluated in the clinic at three months and at six months to evaluate their clinical status as well as the safety and tolerability of IVIG.

RESULTS

All subjects tolerated home-based IVIG treatment as maintenance treatment of CIDP. There were no serious adverse events related to IVIG. Subjects did experience "anticipated" IVIG events post-infusion such as headache and fatigue, which were managed with analgesics and supportive counseling. One subject withdrew consent at end of study due to hospitalization. This event was not related to the IVIG. Another subject experienced a "flare" of CIDP symptoms near the end of the study, however, completed all visits as per protocol. All subjects expressed excellent satisfaction with the individualized therapy, and almost all (nine out of ten) patients preferred home-infusion to hospital-infusion.

CONCLUSION

Intravenous immunoglobulin can be delivered safely and is well tolerated outside the hospital setting in Canada in patients with chronic, stable neuromuscular conditions such as CIDP who have previously tolerated IVIG in the hospital medical day Care Unit.

Subcutaneous IgG in neurologic diseases

Subcutaneous administration of IgG (SCIG) has become widely used in primary immune deficiency diseases but it has only recently been studied for maintenance therapy in autoimmune peripheral neuropathies, such as chronic idiopathic demyelinating polyneuropathy and multifocal motor neuropathy. Weekly self-administration of SCIG is safe and well-tolerated, and results in steady-state serum IgG levels, as contrasted with the peaks and troughs of monthly immune globulin (human) for intravenous use. Freedom from the need for venous access or medical personnel for infusions, flexibility in scheduling, convenience of home therapy, and improved clinical stability due to the steady-state IgG levels, lead many patients to prefer SCIG to immune globulin (human) for intravenous use. Long-term studies are needed to determine if the constant IgG levels and clinical stability translate into better long-term outcomes.

Long-term day-case treatment of peripheral neuromuscular disease with intravenous immunoglobulin: the practice of a regional day-case service in Preston, Lancashire

Neuromuscular disease is one of the most common indications for the use of intravenous immuno-globulin (IVIG). We describe practical aspects of IVIG administration and dosing in long-term treatment, as well as the setting up of a day-case service in a regional neurology unit to provide a streamlined patient experience. An audit of the safety of IVIG administration and patient satisfaction during implementation supported the fact that this is a relatively safe treatment. Standardised assessment methods have been used both to monitor treatment effect and to provide the necessary outcome measures for Department of Health (DOH) monitoring of IVIG use.

Polyclonal immunoglobulin G for autoimmune demyelinating nervous system disorders

Demyelinating diseases with presumed autoimmune pathogenesis are characterised by direct or indirect immune-mediated damage to myelin sheaths, which normally surround nerve fibres to ensure proper electrical nerve conduction. Parenteral administration of polyclonal IgG purified from multi-donor human plasma pools may beneficially modulate these misguided immune reactions via several mechanisms that are outlined in this review. Convincing therapeutic evidence from controlled trials now exists for certain disorders of the peripheral nervous system, including Guillain-Barré syndrome, chronic inflammatory demyelinating polyradiculoneuropathy, and multifocal motor neuropathy. In addition, there is evidence for potential therapeutic benefits of IgG in patients with chronic inflammatory demyelinating diseases of the central nervous system, including multiple sclerosis and neuromyelitis optica. This review introduces these disorders, briefly summarises the established treatment options, and discusses therapeutic evidence for the use of polyclonal immunoglobulins with a particular emphasis on recent clinical trials and meta-analyses.

Chronic inflammatory demyelinating polyneuropathy

OPINION STATEMENT

Chronic Inflammatory polyneuropathies are an important group of neuromuscular disorders that present chronically and progress over more than 8 weeks, being referred to as chronic inflammatory demyelinating polyneuropathy (CIDP). Despite tremendous progress in elucidating disease pathogenesis, the exact triggering event remains unknown. Our knowledge regarding diagnosis and management of CIDP and its variants continues to expand, resulting in improved opportunities for identification and treatment. Most clinical neurologists will be involved in the management of patients with these disorders, and should be familiar with available therapies for CIDP. We review the distinctive clinical, laboratory, and electro-diagnostic features that aid in diagnosis. We emphasize the importance of clinical patterns that define treatment responsiveness and the most appropriate therapies in order to improve prognosis.

Multifocal motor neuropathy, multifocal acquired demyelinating sensory and motor neuropathy, and other chronic acquired demyelinating polyneuropathy variants

Chronic acquired demyelinating neuropathies (CADP) constitute an important group of immune neuromuscular disorders affecting myelin. This article discusses CADP with emphasis on multifocal motor neuropathy, multifocal acquired demyelinating sensory and motor neuropathy, distal acquired demyelinating symmetric neuropathy, and less common variants. Although each of these entities has distinctive laboratory and electrodiagnostic features that aid in their diagnosis, clinical characteristics are of paramount importance in diagnosing specific conditions and determining the most appropriate therapies. Knowledge regarding pathogenesis, diagnosis, and management of these disorders continues to expand, resulting in improved opportunities for identification and treatment.

Childhood chronic inflammatory demyelinating polyneuroradiculopathy--three cases and a review of the literature

BACKGROUND

Chronic inflammatory demyelinating polyneuroradiculopathy (CIDP) is an autoimmune disease of the peripheral nervous system, causing demyelination and even axonal degeneration. In children, abnormal gait as a first sign of muscle weakness is a frequent reason to seek medical attention. Diagnosis is made on the basis of clinical characteristics, electromyography and nerve conduction studies, and elevated protein in cerebrospinal fluid.

AIMS

We present three new cases of CIDP. The literature was reviewed in order to obtain more information on presentation, outcome and treatment strategies world-wide.

RESULTS

The course of disease can be relapsing-remitting or chronic-progressive. From case series it is known that first-line immunotherapy (intravenously administered immunoglobulin, corticosteroids or plasmapheresis) is initially of benefit in most children with CIDP. There is little evidence, however, on second-line therapies as azathioprine, cyclosporine A, mycophenolate mofetil, methothrexate, cyclophosphamide and IFN alpha. Although the outcome of children with CIDP is generally regarded to be good, disease related disability can be severe.

CONCLUSION

Childhood CIDP is rare. In general and in comparison to adults, children tend to have a more acute progressive onset, with more severe symptoms. Showing a higher tendency towards a relapsing-remitting course, children often show a better and faster improvement after therapy, and a more favorable outcome. Swift recognition of CIDP and empiric start of treatment are considered important to avoid potentially irreversible axonal damage and associated disability. Response to first-line therapies is usually favorable, however recommendations regarding the choice of second-line therapy can only be made on the basis of current practice described in case reports. Safety and efficacy data are insufficient. The cases described show that trial and error are often involved in finding an optimal treatment strategy, especially in those patients refractory to first-line treatment or with a prolonged course. Clinical experience with immunomodulatory treatment is paramount when treating children with CIDP.

New Frontiers in Subcutaneous Immunoglobulin Treatment

Subcutaneous immunoglobulin (SCIG) treatment provides stable serum immunoglobulin G (IgG) levels, is associated with fewer systemic adverse events than intravenous immunoglobulin (IVIG) treatment, and offers the convenience of home therapy. In clinical practice, IVIG is still used preferentially for initiation of treatment in newly diagnosed patients with primary immunodeficiency (PI) and for immunomodulatory therapy, such as treatment of peripheral neuropathies, when high doses are believed to be necessary. The authors discuss recent experience in using SCIG in place of IVIG in these settings. SCIG has been successfully used for initiation of therapy in previously untreated PI patients. Seventeen of 18 PI patients achieved serum IgG levels ≥5 g/L after the loading phase. Daily treatment was well tolerated and provided opportunities for patient/parent training in self-infusion. SCIG has been used for maintenance therapy in multifocal motor neuropathy (MMN) in three recent clinical trials, with good efficacy and tolerability results. Seven of eight MMN patients maintained serum IgG levels of 14-22 g/L with a mean dose of 272 mg/kg/week, had stable muscle strength, and felt comfortable with self-administration. Four patients with polymyositis or dermatomyositis achieved improvement in serum creatine kinase levels and muscle strength with SCIG therapy. Recent experience with SCIG suggests that traditional concepts of immunoglobulin therapy may be challenged to increase available therapy options. SCIG can be used to achieve high IgG levels within several days in untreated PI patients and to maintain high serum levels, as shown in patients with MMN.