Subcutaneous immunoglobulin therapy for the treatment of multifocal motor neuropathy: a case report

Dramatic clinical response to ultra-high dose IVIg in otherwise treatment resistant inflammatory neuropathies

BACKGROUND

Intravenous immunoglobulin (IVIg) has short and long-term efficacy in both chronic inflammatory demyelinating polyneuropathy (CIDP) and multifocal motor neuropathy with conduction block (MMNCB). There is potential for under and over-treatment if trial regimens are strictly adhered to in clinical practice where titrating dose to clinical response is recommended.

METHODS

We report the response to high-dose IVIg (>2 g/kg/6 weeks) in a subgroup of patients with definite CIDP or MMNCB who were unresponsive to 'usual' dosing. IVIg frequency and dosing was determined for each individual by subjective and objective outcome measures for impairment, grip strength, and activity and participation.

RESULTS

Six patients (three with chronic inflammatory demyelinating polyneuropathy (CIDP), three with MMN) were included. Two patients (one CIDP and one MMNCB) returned to full-time work on fractionated IVIg doses of 5 g/kg/month and 9 g/kg/month. Patient three (CIDP) failed numerous other immunosuppressants but responded to short-term fractionated 4 g/kg/month of IVIg. Patient four has severe, refractory, childhood-onset CIDP, remains stable but dependent currently on 6.9 g/kg/month of IVIg. Patients five and six, both with MMNCB, required short term 4.5-5 g/kg/month to recover significant bilateral hand strength. No IVIg-related adverse events occurred in any individual.

CONCLUSIONS

These six cases demonstrate the safety and effectiveness of a treatment approach that includes individualised but evidence-based clinical assessment and, when necessary, high-doses of IVIg to restore patients' strength and ability to participate in activities of daily activities. Careful patient selection is important.

Recent advances in use of fresh frozen plasma, cryoprecipitate, immunoglobulins, and clotting factors for transfusion support in patients with hematologic disease

Hematologic diseases include a broad range of acquired and congenital disorders, many of which affect plasma proteins that control hemostasis and immune responses. Therapeutic interventions for these disorders include transfusion of plasma, cryoprecipitate, immunoglobulins, or convalescent plasma-containing therapeutic antibodies from patients recovering from infectious diseases, as well as concentrated pro- or anticoagulant factors. This review will focus on recent advances in the uses of plasma and its derivatives for patients with acquired and congenital hematologic disorders.

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.

Individualized immunoglobulin therapy in chronic immune-mediated peripheral neuropathies

Despite the well-recognized importance of immunoglobulin therapy individualization during the treatment of chronic inflammatory demyelinating polyneuropathy (CIDP), the pathway to best achieve optimization is unknown. There are many pharmacokinetic and immunobiologic variables that can potentially influence the appropriateness of any individual therapy. Although identification of specific autoantibodies and their targets has only been accomplished in a minority of patients with CIDP, already the diagnostic and treatment implications of specific autoantibody detection are being realized. Individual variability in IgG pharmacokinetic properties including IgG catabolic rates and distribution, as well as the IgG level necessary for disease control also require consideration during the optimization process. For optimization to be successful there must be a measure of treatment response that has a clinically meaningful interpretation. There are currently available well-defined and validated clinical assessment tools and outcome measures that are well suited for this purpose. While there remains much to learn on how best to manipulate immunopathology and immunoglobulin pharmacokinetics in the most favorable way, there currently exists an understanding of these principles to a degree sufficient to begin to develop rational and evidence-based treatment optimization strategies.

An idiopathic thrombocytopenic purpura with polyneuropathy

Concurrent association of idiopathic thrombocytopenic purpura (ITP) and peripheral neuropathy is a rare condition. There are only few case reports published concerning peripheral neuropathy with ITP. One of the etiopathogenetic mechanisms proposed is intraneural hemorrhage, but the pathogenesis is not fully understood. Autoimmune nature with common antibodies to the platelets and the nerve´s myelin sheath should also be considered. Here we describe a 47-year-old woman, with a family history of autoimmune diseases. She was diagnosed 2 years ago with ITP and later developed a chronic combined inflammatory demyelinating polyneuropathy. Treatment with high-dose steroids was initiated with a poor response. The patient showed a clear improvement in platelet count and in the peripheral neuropathy symptoms when treatment with intravenous immunoglobulin was administered. Common etiologic mechanism of the two diseases should be considered, both, because of the simultaneous time of development and a similar response to intravenous immunoglobulin treatment.

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.

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 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.

Quantitative Evidence of Wear-Off Effect at the End of the Intravenous IgG (IVIG) Dosing Cycle in Primary Immunodeficiency

PURPOSE

Intravenous IgG (IVIG) treatment wear-off is commonly experienced by patients, who report increased susceptibility to infection, and decreased quality of life towards the end of their 3- or 4-week dosing cycle, when serum IgG levels approach their trough. We quantified IVIG wear-off in terms of treatment efficacy and patient well-being.

METHODS

Data were collected from patients enrolled in three Phase III trials of Sandoglobulin NF Liquid or Privigen, treated every 3- or 4- weeks. Pooled analyses of raw patient data compared the rate of infection and other clinical outcomes during the course of the dosing cycle. Subjective symptoms of wear-off were quantified by comparing patient-reported overall well-being scores.

RESULTS

The probability of a first infection in the final week of the IVIG cycle was 1.26 (95% confidence intervals [CI]: 0.76-2.11; p = 0.3621) and 1.55 (95% CI: 1.04-2.32; p = 0.0314) times higher than in the first week, for patients on a 3-week cycle and 4-week dosing cycles, respectively. Wear-off, as manifested by a decrease in overall well-being, was experienced in 10% of all cycles and reported at least once by 61% of the patients on a 3-week cycle, and 43% of those on a 4-week cycle.

CONCLUSIONS

These findings confirm the existence of decreased efficacy (treatment wear-off) towards the end of a 3-4 week IVIG dosing cycle, and provide a quantifiable evaluation to a phenomenon typically reported anecdotally. For patients experiencing wear-off, increasing the IgG dose or shortening the dosing interval and/or a switch to SCIG may be beneficial.

Human immune globulin infusion in the management of multifocal motor neuropathy

Multifocal motor neuropathy (MMN) is a debilitating and rare disease causing profound weakness with minimal to no sensory symptoms. Conduction block is frequently seen on electrodiagnostic testing. An immune-mediated pathology is suspected though the exact underlying pathophysiology has yet to be elucidated. The presence of anti-GM1 ganglioside IgM antibodies coupled with favorable response to intravenous and subcutaneous immunoglobulins supports a complement-mediated mechanism which leads to destruction of nerve tissue with probable predilection to the nodes of Ranvier. High-dose immunoglobulin currently is the only treatment with proven efficacy for MMN patients. Unfortunately, many patients experience decreased responsiveness to immunoglobulins over time, requiring higher and more frequent dosing. In this review, we will focus on the pharmacology, efficacy, safety, and tolerability of intravenous and subcutaneous immune globulin infusion for treatment of MMN.

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.

Rapid and reversible responses to IVIG in autoimmune neuromuscular diseases suggest mechanisms of action involving competition with functionally important autoantibodies

Intravenous immunoglobulin (IVIG) is widely used in autoimmune neuromuscular diseases whose pathogenesis is undefined. Many different effects of IVIG have been demonstrated in vitro, but few studies actually identify the mechanism(s) most important in vivo. Doses and treatment intervals are generally chosen empirically. Recent studies in Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy show that some effects of IVIG are readily reversible and highly dependent on the serum IgG level. This suggests that in some autoantibody-mediated neuromuscular diseases, IVIG directly competes with autoantibodies that reversibly interfere with nerve conduction. Mechanisms of action of IVIG which most likely involve direct competition with autoantibodies include: neutralization of autoantibodies by anti-idiotypes, inhibition of complement deposition, and increasing catabolism of pathologic antibodies by saturating FcRn. Indirect immunomodulatory effects are not as likely to involve competition and may not have the same reversibility and dose-dependency. Pharmacodynamic analyses should be informative regarding most relevant mechanism(s) of action of IVIG as well as the role of autoantibodies in the immunopathogenesis of each disease. Better understanding of the role of autoantibodies and of the target(s) of IVIG could lead to more efficient use of this therapy and better patient outcomes.

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.

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.

Variability in intravenous immunoglobulin G regimens for autoimmune neuromuscular disorders

AIMS

We reviewed the intravenous immunoglobulin G (IVIG) dispensing records of a specialty pharmacy to characterize the IVIG treatment regimens used for chronic inflammatory demyelinating polyneuropathy (CIDP) and myasthenia gravis (MG) in community practice.

METHODS

Anonymized records were selected based on International Classification of Diseases, Ninth Revision (ICD-9) codes and IVIG treatment for > 1 month. Each patient's immunoglobulin G (IgG) dose per infusion (mg/kg/dose) was multiplied by the number of doses per month (30.5 days divided by the dosing interval in days) to yield the total monthly dose (mg/kg/month). Data were analyzed and summarized using descriptive statistics.

RESULTS

Forty-six patients (median age, 56.5 years; range, 8-86 years) fulfilled the inclusion criteria. Thirty-one patients with CIDP received IgG at 7- to 92-day intervals (mean [standard deviation (SD)], 28 [16] days). The mean (SD) IgG dose was 75 (60) g/dose, equivalent to 866 (623) mg/kg/dose and 1145 (778) mg/kg/month. Six patients with stable MG received IVIG or subcutaneous IgG at 3.5- to 61-day intervals (28 [20] days) at a mean (SD) IgG dose of 39 (15) g/dose, equivalent to 405 (108) mg/kg/dose and 783 (680) mg/kg/month. Nine patients with MG with acute exacerbations received IgG at 7- to 42-day intervals (22 [12] days) at a mean (SD) dose of 40 (21) g/dose, equivalent to 403 (172) mg/kg/dose and 641 (288) mg/kg/month. One patient with CIDP and 4 patients with MG were treated with weekly subcutaneous IgG injections.

CONCLUSION

Although patients with CIDP and MG are treated with mean total monthly IgG doses similar to those approved by the US Food and Drug Administration, the individual doses and intervals vary considerably, suggesting that physicians may be adjusting IgG dosing according to each patient's clinical condition and treatment response. Further study is necessary to determine the criteria used to adjust IgG treatment regimens and whether these adjustments optimize clinical outcomes while limiting overall costs.

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.

Multifocal motor neuropathy

Multifocal motor neuropathy (MMN) was first described in 1988 as a purely motor neuropathy affecting multiple motor nerves. The diagnosis was based entirely on demonstrating electrophysiological evidence of a conduction block (CB) that selectively affected motor axons, with sparing of sensory axons even through the site of motor CB. Subsequently, a similar disorder was reported but with absence of demonstrable CB on routine nerve conduction studies and there is still some debate as to whether MMN without CB is related to MMN. MMN is thought to be an inflammatory neuropathy related to an immune attack on motor nerves. The conventional hypothesis is that the primary pathology is segmental demyelination, but recent research raises the possibility of a primary axonopathy. Anti-GM1 antibodies can be found in some patients but it is unclear whether these antibodies are pathogenic. Intravenous immunoglobulin is the mainstay of treatment but other immunosuppressive treatments can also be effective.

A comparison between intravenous and subcutmaneous immunogobulin

Multifocal motor neuropathy (MMN) is a rare immune-mediated disease that presents with predominantly distal motor weakness in one or more limbs without sensory loss. Symptoms may give riseto functional impairment and consequently may affect quality of life. High-dose intravenous immunoglobulin's therapy (IVIg) is the current mainstay treatment, however, subcutaneous immunoglobuli(SCIg) is emerging as a viable alternative. The purpose of this study was to explore the patients' experience of SCIg and ascertain if those receiving it had an improved quality of life and treatmentsatisfaction compared to those receiving IVIg. Using a mixed method approach this paper will present its findings and key implications for clinical and research practice are considered. The results from this study suggest that home SCIg therapy may prove a more desirable treatment option than IVIg for a proportion of MMN patients.