Intravenous immunoglobulin for maintenance treatment of chronic inflammatory demyelinating polyneuropathy: a multicentre, open-label, 52-week phase III trial

A pathophysiological and mechanistic review of chronic inflammatory demyelinating polyradiculoneuropathy therapy

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an immune-mediated disease of the peripheral nerves characterized by proximal and distal muscle weakness and sensory abnormalities. CIDP has been associated with various pathophysiological mechanisms that are not fully understood and that likely differ across groups of patients. It has been proposed that an interplay of different immunopathological mechanisms including the cellular, humoral and complement pathways play a key role in peripheral nerve damage in CIDP. Currently approved treatments and therapies in research often target different potential pathophysiological mechanisms. The efficacy of these different treatments can shed light on the prominence of particular pathophysiological pathways in subsets of patients with CIDP. For example, the complement pathway plays a key role in promoting macrophage-mediated demyelination, and complement inhibitors are under development as new targets in CIDP treatment, with mixed results. The neonatal Fc receptor (FcRn) has also been targeted as a promising treatment avenue due to its role in immunoglobulin G degradation. Efgartigimod is the first FcRn blocker approved for the treatment of CIDP. This review provides an overview of key proposed mechanisms of action in CIDP pathophysiology in the context of both basic scientific findings and treatment targets in recent clinical studies.

Maintenance Intravenous Immunoglobulin Therapy for Chronic Inflammatory Demyelinating Polyneuropathy: 18-Month Post-marketing Surveillance in 103 Patients

Objective The efficacy of maintenance intravenous immunoglobulin (IVIg) therapy has been established to prevent relapse in chronic inflammatory demyelinating polyneuropathy (CIDP). This prospective post-marketing surveillance study evaluated the treatment duration, efficacy, and safety of maintenance IVIg therapy in Japanese patients with CIDP. Methods Patients were registered between June 2017 and December 2018. After induction of IVIg therapy (0.4 g/kg/day for 5 consecutive days), patients received maintenance IVIg (1.0 g/kg every 3 weeks). The observation period was 18 months. Efficacy in preventing relapse was assessed using the Inflammatory Neuropathy Cause and Treatment (INCAT) disability score. Relapse was defined as a worsening of the INCAT score by ≥1 from baseline. Patients The efficacy population comprised 103 patients (80 with typical CIDP and 23 with CIDP variants). Results During the observation period, 86 (83%) patients were scheduled to continue maintenance IVIg therapy during the observation period, and the relapse rate was 24% (21/86). In the remaining 17 patients who showed continuous remission, maintenance IVIg therapy was stopped (mean, 136 days after the start), and the relapse rate was 24% (4/17). One serious adverse drug reaction of cardiac failure was reported. Conclusion In this post-marketing surveillance, most (83%) patients with CIDP were scheduled to continue maintenance IVIg for 18 months, with a relapse rate of 24%, indicating long-term efficacy. Maintenance IVIg therapy was rarely withdrawn, and the relapse rate after withdrawal was 24%. Further studies are required to determine the optimal maintenance IVIg dose and duration.

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.

Intravenous immunoglobulin for chronic inflammatory demyelinating polyradiculoneuropathy

BACKGROUND

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) causes progressive or relapsing weakness and numbness of the limbs, which lasts for at least two months. Uncontrolled studies have suggested that intravenous immunoglobulin (IVIg) could help to reduce symptoms. This is an update of a review first published in 2002 and last updated in 2013.

OBJECTIVES

To assess the efficacy and safety of intravenous immunoglobulin in people with chronic inflammatory demyelinating polyradiculoneuropathy.

SEARCH METHODS

We searched the Cochrane Neuromuscular Specialised Register, CENTRAL, MEDLINE, Embase, and two trials registers on 8 March 2023.

SELECTION CRITERIA

We selected randomised controlled trials (RCTs) and quasi-RCTs that tested any dose of IVIg versus placebo, plasma exchange, or corticosteroids in people with definite or probable CIDP.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcome was significant improvement in disability within six weeks after the start of treatment, as determined and defined by the study authors. Our secondary outcomes were change in mean disability score within six weeks, change in muscle strength (Medical Research Council (MRC) sum score) within six weeks, change in mean disability score at 24 weeks or later, frequency of serious adverse events, and frequency of any adverse events. We used GRADE to assess the certainty of evidence for our main outcomes.

MAIN RESULTS

We included nine RCTs with 372 participants (235 male) from Europe, North America, South America, and Israel. There was low statistical heterogeneity between the trial results, and the overall risk of bias was low for all trials that contributed data to the analysis. Five trials (235 participants) compared IVIg with placebo, one trial (20 participants) compared IVIg with plasma exchange, two trials (72 participants) compared IVIg with prednisolone, and one trial (45 participants) compared IVIg with intravenous methylprednisolone (IVMP). We included one new trial in this update, though it contributed no data to any meta-analyses. IVIg compared with placebo increases the probability of significant improvement in disability within six weeks of the start of treatment (risk ratio (RR) 2.40, 95% confidence interval (CI) 1.72 to 3.36; number needed to treat for an additional beneficial outcome (NNTB) 4, 95% CI 3 to 5; 5 trials, 269 participants; high-certainty evidence). Since each trial used a different disability scale and definition of significant improvement, we were unable to evaluate the clinical relevance of the pooled effect. IVIg compared with placebo improves disability measured on the Rankin scale (0 to 6, lower is better) two to six weeks after the start of treatment (mean difference (MD) -0.26 points, 95% CI -0.48 to -0.05; 3 trials, 90 participants; high-certainty evidence). IVIg compared with placebo probably improves disability measured on the Inflammatory Neuropathy Cause and Treatment (INCAT) scale (1 to 10, lower is better) after 24 weeks (MD 0.80 points, 95% CI 0.23 to 1.37; 1 trial, 117 participants; moderate-certainty evidence). There is probably little or no difference between IVIg and placebo in the frequency of serious adverse events (RR 0.82, 95% CI 0.36 to 1.87; 3 trials, 315 participants; moderate-certainty evidence). The trial comparing IVIg with plasma exchange reported none of our main outcomes. IVIg compared with prednisolone probably has little or no effect on the probability of significant improvement in disability four weeks after the start of treatment (RR 0.91, 95% CI 0.50 to 1.68; 1 trial, 29 participants; moderate-certainty evidence), and little or no effect on change in mean disability measured on the Rankin scale (MD 0.21 points, 95% CI -0.19 to 0.61; 1 trial, 24 participants; moderate-certainty evidence). There is probably little or no difference between IVIg and prednisolone in the frequency of serious adverse events (RR 0.45, 95% CI 0.04 to 4.69; 1 cross-over trial, 32 participants; moderate-certainty evidence). IVIg compared with IVMP probably increases the likelihood of significant improvement in disability two weeks after starting treatment (RR 1.46, 95% CI 0.40 to 5.38; 1 trial, 45 participants; moderate-certainty evidence). IVIg compared with IVMP probably has little or no effect on change in disability measured on the Rankin scale two weeks after the start of treatment (MD 0.24 points, 95% CI -0.15 to 0.63; 1 trial, 45 participants; moderate-certainty evidence) or on change in mean disability measured with the Overall Neuropathy Limitation Scale (ONLS, 1 to 12, lower is better) 24 weeks after the start of treatment (MD 0.03 points, 95% CI -0.91 to 0.97; 1 trial, 45 participants; moderate-certainty evidence). The frequency of serious adverse events may be higher with IVIg compared with IVMP (RR 4.40, 95% CI 0.22 to 86.78; 1 trial, 45 participants, moderate-certainty evidence).

AUTHORS' CONCLUSIONS

Evidence from RCTs shows that IVIg improves disability for at least two to six weeks compared with placebo, with an NNTB of 4. During this period, IVIg probably has similar efficacy to oral prednisolone and IVMP. Further placebo-controlled trials are unlikely to change these conclusions. In one large trial, the benefit of IVIg compared with placebo in terms of improved disability score persisted for 24 weeks. Further research is needed to assess the long-term benefits and harms of IVIg relative to other treatments.

Restoring immune tolerance in pemphigus vulgaris

Intravenous immunoglobulin (IVIg), a preparation of polyclonal serum IgG pooled from numerous blood donors, has been used for nearly three decades and is proving to be an efficient treatment for many autoimmune blistering diseases, including pemphigus vulgaris (PV). Despite its widespread use and therapeutic success, its mechanisms of action are not completely understood. Some of its anti-inflammatory and immunomodulatory actions have been studied. In this study, the authors present a twenty-year follow-up of 21 patients with clinical and immunopathological confirmed PV, treated with IVIg as monotherapy, according to an established published protocol. IVIg therapy produced long-term sustained, clinical, serological, and immunopathological remission. For 20 y, these patients received no drugs and experienced no disease. This observation suggests that there was the establishment of immune balance or restoration of immune regulation in these PV patients. Twelve (57%) patients experienced no relapse during follow-up. Six (29%) patients experienced a relapse due to acute stress or post-coronavirus infection and/or vaccination. Reinstitution of IVIg resulted in prompt sustained recovery. Three (14.2%) patients, in clinical and serological remission, died due to unrelated causes. No severe adverse effects from IVIg were documented in all 21 patients. The simultaneous or sequential anti-inflammatory and immunomodulatory effects of IVIg may have influenced the long-term clinical remission observed. This study provides a human prototype to examine the pathophysiology of autoimmunity and a model to study immune regulation and mechanisms that can facilitate restoring immune tolerance.

Chronic Inflammatory Demyelinating Polyneuropathy and Evaluation of the Visual Evoked Potentials: A Review of the Literature

Chronic inflammatory demyelinating polyneuropathy (CIDP) is a rare autoimmune disorder characterised by the progressive demyelination of peripheral nerves, resulting in motor and sensory deficits. While much research has focused on clinical and electrophysiological aspects of CIDP, there is an emerging interest in exploring its impact on the visual system through visual evoked potentials (VEPs). This comprehensive review synthesises existing literature on VEP findings in CIDP patients, shedding light on their potential diagnostic and prognostic value. The review thoroughly examines studies spanning the last two decades, exploring VEP abnormalities in CIDP patients. Notably, VEP studies have consistently revealed prolonged latencies and reduced amplitudes in CIDP patients compared to healthy controls. These alterations in VEP parameters suggest that the demyelinating process extends beyond the peripheral nervous system to affect the central nervous system, particularly the optic nerve and its connections. The correlation between VEP abnormalities and clinical manifestations of CIDP, such as visual impairment and sensory deficits, underscores the clinical relevance of VEP assessment in CIDP management. Furthermore, this review addresses the potential utility of VEPs in aiding CIDP diagnosis and monitoring disease progression. VEP abnormalities may serve as valuable biomarkers for disease activity, helping clinicians make timely therapeutic decisions. Moreover, this review discusses the limitations and challenges associated with VEP assessment in CIDP, including variability in recording techniques and the need for standardised protocols. In conclusion, this review highlights the evolving role of VEPs as a non-invasive tool in CIDP evaluation. The consistent VEP abnormalities observed in CIDP patients suggest the involvement of the central nervous system in this demyelinating disorder. As our understanding of CIDP and its pathophysiology continues to evolve, further research in this area may lead to improved diagnostic accuracy and monitoring strategies, ultimately enhancing the clinical management of CIDP patients.

Symptom and Treatment Satisfaction in Members of the US and Canadian GBS/CIDP Foundations with a Diagnosis of Chronic Inflammatory Demyelinating Polyneuropathy

INTRODUCTION

Current guidelines for defining good outcomes in patients with chronic inflammatory demyelinating polyneuropathy (CIDP) are predominately defined by experts. At present, we do not have a patient-anchored definition of what constitutes a "good" outcome. Our study aimed to assess the symptom burden of people living with CIDP, as well as satisfaction with treatments and clinical outcomes.

METHODS

We conducted an online-survey in CIDP patients registered with the US and Canadian GBS/CIDP foundations. Respondents answered general demographic and clinical questions, as well as satisfaction with current symptom burden and treatments, plus validated outcome measures.

RESULTS

A total of 318 individuals with self-reported CIDP completed the online survey, of whom 128 (40%) considered their current disease burden as satisfactory while 190 (60%) did not. Of 305 patients who answered the treatment satisfaction question, 222(74%) were satisfied with their treatments. Patients who were satisfied with their current symptoms had, on average, better scores in quality of life and disease severity scales, although regression modeling showed that only ability to walk, stable symptoms, and health utility scores were associated with symptom satisfaction. Treatment satisfaction was associated with stable symptoms, use of IVIG, and use of one versus no medication.

CONCLUSIONS

A high proportion of members of the US and Canadian GBS/CIDP Foundations reporting a diagnosis of CIDP were unsatisfied with current symptoms, despite a high level of overall satisfaction with treatments. There is an unmet need for improving long-term outcomes in people with a diagnosis of CIDP, and for studying patient-centered long-term treatment goals.

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.

Safety and Tolerability of Intravenous Immunoglobulin in Chronic Inflammatory Demyelinating Polyneuropathy: Results of the ProCID Study

BACKGROUND AND AIMS

The ProCID study evaluated the efficacy and safety of three doses of a 10% liquid intravenous immunoglobulin (IVIg) preparation (panzyga®) in patients with chronic inflammatory demyelinating polyneuropathy (CIDP). This report describes the safety findings.

METHODS

Patients were randomised to receive a 2.0 g/kg induction dose followed by maintenance doses of either 0.5, 1.0 or 2.0 g/kg IVIg every 3 weeks over 24 weeks.

RESULTS

All 142 enrolled patients were included in the safety analyses. In total, 286 treatment-emergent adverse events (TEAEs) were reported in 89 patients, of which 173 (60.5%) were considered treatment-related. Most TEAEs were of mild severity. Eleven serious TEAEs were reported in 6 patients. Two serious TEAEs in one patient (headache and vomiting) were considered related to treatment, which resolved without study discontinuation. No treatment-related thrombotic events, haemolytic transfusion reactions or deaths occurred. One patient discontinued the study due to a TEAE (allergic dermatitis) probably related to IVIg. Headache was the only dose-dependent TEAE, with incidences ranging from 2.9 to 23.7%, the incidence of all other TEAEs was similar across treatment groups. Most TEAEs were associated with the induction dose infusion, and the rate of TEAEs decreased thereafter. The median (IQR) daily IVIg dose was 78 (64-90) g, and 94.4% of patients tolerated the maximal infusion rate of 0.12 ml/kg/min without pre-medication.

INTERPRETATION

Infusions of 10% IVIg at doses up to 2.0 g/kg with high infusion rates were safe and well tolerated in patients with CIDP.

CLINICAL TRIAL NUMBERS

EudraCT 2015-005443-14, NCT02638207.

Beneficial effects and safety of traditional Chinese medicine for chronic inflammatory demyelinating polyradiculoneuropathy: A case report and literature review

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an immune-mediated neuropathy. First-line treatments for CIDP include corticosteroids, intravenous immunoglobulin, and plasma exchange. However, the application is always limited by high costs, effectiveness, and adverse events. This study investigated a new potentially effective and safe therapeutic treatment to alleviate CIDP symptoms and improve the quality of life. In the present case, a 47-year-old rural woman presented with weakness and numbness of progressive extremities. She was diagnosed with CIDP based on abnormal cerebrospinal fluid and electromyography. The patient was treated with intravenous dexamethasone for 1 week and with Huangqi-Guizhi-Wuwu and Bu-Yang-Huan-Wu decoctions for 90 days. Surprisingly, after the treatment, the weakness and numbness were eliminated, and the quality of life improved. The varying INCAT, MRC, and BI scores also reflected the treatment effects. After 8 months of discharge, the symptoms did not relapse during the follow-up. We also searched “traditional Chinese medicine (TCM)” and “CIDP” in PubMed, EMBASE, the Web of Science, the Cochrane Library, the Chinese National Knowledge Infrastructure Databases, Wanfang Data, and the Chongqing Chinese Science and Technology Periodical Database. Finally, only ten studies were included in the literature review. Three studies were randomized controlled trials, and seven were case reports or case series. There were 419 CIDP patients, but all study sites were in China. Nine TCM formulas involving 44 herbs were reported, with Huang Qi (Astragalus membranaceus) being the most important herb. In conclusion, the case and literature demonstrated that TCM treatment might be a more effective, low-cost, and safe option for treating CIDP. Although these preliminary findings are promising, a larger sample size and higher-quality randomized clinical trials are urgently required to confirm our findings.

Update on therapy of chronic immune-mediated neuropathies

Chronic immune-mediated neuropathies, including chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), neuropathies associated with monoclonal gammopathy, and multifocal motor neuropathy (MMN), are a group of disorders deemed to be caused by an immune response against peripheral nerve antigens. Several immune therapies have been reported to be variably effective in these neuropathies including steroids, plasma exchange, and high-dose intravenous (IVIg) or subcutaneous (SCIg) immunoglobulins. These therapies are however far from being invariably effective and may be associated with a number of side effects leading to the use of immunosuppressive agents whose efficacy has not been so far confirmed in randomized trials. More recently, new biological agents, such as rituximab, have proved to be effective in patients with neuropathy associated with IgM monoclonal gammopathy and are currently tested in CIDP.

Current and Emerging Pharmacotherapeutic Interventions for the Treatment of Peripheral Nerve Disorders

Peripheral nerve disorders are caused by a range of different aetiologies. The range of causes include metabolic conditions such as diabetes, obesity and chronic kidney disease. Diabetic neuropathy may be associated with severe weakness and the loss of sensation, leading to gangrene and amputation in advanced cases. Recent studies have indicated a high prevalence of neuropathy in patients with chronic kidney disease, also known as uraemic neuropathy. Immune-mediated neuropathies including Guillain-Barré syndrome and chronic inflammatory demyelinating polyradiculoneuropathy may cause significant physical disability. As survival rates continue to improve in cancer, the prevalence of treatment complications, such as chemotherapy-induced peripheral neuropathy, has also increased in treated patients and survivors. Notably, peripheral neuropathy associated with these conditions may be chronic and long-lasting, drastically affecting the quality of life of affected individuals, and leading to a large socioeconomic burden. This review article explores some of the major emerging clinical and experimental therapeutic agents that have been investigated for the treatment of peripheral neuropathy due to metabolic, toxic and immune aetiologies.

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.

Clinical outcome of CIDP one year after start of treatment: a prospective cohort study

OBJECTIVE

To assess clinical outcome in treatment-naive patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP).

METHODS

We included adult treatment-naive patients participating in the prospective International CIDP Outcome Study (ICOS) that fulfilled the European Federation of Neurological Societies/Peripheral Nerve Society (EFNS/PNS) diagnostic criteria for CIDP. Patients were grouped based on initial treatment with (1) intravenous immunoglobulin (IVIg), (2) corticosteroid monotherapy or (3) IVIg and corticosteroids (combination treatment). Outcome measures included the inflammatory Rasch-built overall disability scale (I-RODS), grip strength, and Medical Research Council (MRC) sum score. Treatment response, treatment status, remissions (improved and untreated), treatment changes, and residual symptoms or deficits were assessed at 1 year.

RESULTS

Forty patients were included of whom 18 (45%) initially received IVIg, 6 (15%) corticosteroids, and 16 (40%) combination treatment. Improvement on ≥ 1 of the outcome measures was seen in 31 (78%) patients. At 1 year, 19 (48%) patients were still treated and fourteen (36%) patients were in remission. Improvement was seen most frequently in patients started on IVIg (94%) and remission in those started on combination treatment (44%). Differences between groups did not reach statistical significance. Residual symptoms or deficits ranged from 25% for neuropathic pain to 96% for any sensory deficit.

CONCLUSIONS

Improvement was seen in most patients. One year after the start of treatment, more than half of the patients were untreated and around one-third in remission. Residual symptoms and deficits were common regardless of treatment.

Electrophysiological predictors of response to subcutaneous immunoglobulin therapy in chronic inflammatory demyelinating polyneuropathy

OBJECTIVE

To assess axonal function prior to subcutaneous immunoglobulin (SCIG) therapy or placebo in relation to relapse in chronic inflammatory demyelinating polyneuropathy (CIDP) to determine whether axonal damage can predict therapy response.

METHODS

Relapse rates in patients from the Polyneuropathy and Treatment with Hizentra (PATH) study, where patients were treated with placebo or SCIG (IgPro20), were analyzed by baseline (post-intravenous immunoglobulin stabilization) axonal damage (≤1 mV peroneal compound muscle action potential) status.

RESULTS

In patients with non-axonal damage, relapses were significantly higher with placebo (73.0%) than IgPro20 (0.2 g/kg: 39.1%, 0.4 g/kg: 19.2%). In patients with axonal damage, IgPro20 had no effect on relapse (placebo: 25.0%, IgPro20: 0.2 g/kg: 30.0%, 0.4 g/kg: 19.4%). Patients with axonal damage relapsed significantly less on placebo versus non-axonal damage, but they also demonstrated higher baseline disability.

CONCLUSION

Axonal damage may correspond to relapse upon treatment withdrawal; patients with axonal damage relapse less, possibly reflecting poor response to immunoglobulin therapy, while non-axonal damage patients may experience more relapse, perhaps indicating better treatment response.

SIGNIFICANCE

In CIDP patients with axonal loss, immunoglobulin therapy may not be as effective. Assessing axonal damage could help guide therapy, with immunoglobulins ideally used before substantial axonal damage arises.

Anti-Neurofascin 155 Antibody-Positive Chronic Inflammatory Demyelinating Polyneuropathy/Combined Central and Peripheral Demyelination: Strategies for Diagnosis and Treatment Based on the Disease Mechanism

Chronic inflammatory demyelinating polyneuropathy (CIDP) is an immune-mediated demyelinating disease of the peripheral nervous system (PNS). A small number of CIDP patients harbors autoantibodies against nodal/paranodal proteins, such as neurofascin 155 (NF155), contactin 1, and contactin-associated protein 1. In most cases, the predominant immunoglobulin (IgG) subclass is IgG4. Node/paranode antibody-positive CIDP demonstrates distinct features compared with antibody-negative CIDP, including a poor response to intravenous immunoglobulin. The neuropathology of biopsied sural nerve shows Schwann cell terminal loop detachment from axons without macrophage infiltration or inflammation. This is partly attributable to IgG4, which blocks protein-protein interactions without inducing inflammation. Anti-NF155 antibody-positive (NF155⁺) CIDP is unique because of the high frequency of subclinical demyelinating lesions in the central nervous system (CNS). This is probably because NF155 coexists in the PNS and CNS. Such cases showing demyelinating lesions in both the CNS and PNS are now termed combined central and peripheral demyelination (CCPD). NF155⁺ CIDP/CCPD commonly presents hypertrophy of spinal nerve roots and cranial nerves, such as trigeminal and oculomotor nerves, and extremely high levels of cerebrospinal fluid (CSF) protein, which indicates nerve root inflammation. In the CSF, the CXCL8/IL8, IL13, TNFα, CCL11/eotaxin, CCL2/MCP1, and IFNγ levels are significantly higher and the IL1β, IL1ra, and GCSF levels are significantly lower in NF155⁺ CIDP than in non-inflammatory neurological diseases. Even compared with anti-NF155 antibody-negative (NF155^-) CIDP, the CXCL8/IL8 and IL13 levels are significantly higher and the IL1β and IL1ra levels are significantly lower than those in NF155⁺ CIDP. Canonical discriminant analysis revealed NF155⁺ and NF155^- CIDP to be separable with IL4, IL10, and IL13, the three most significant discriminators, all of which are required for IgG4 class switching. Therefore, upregulation of both Th2 and Th1 cytokines and downregulation of macrophage-related cytokines are characteristic of NF155⁺ CIDP, which explains spinal root inflammation and the lack of macrophage infiltration in the sural nerves. All Japanese patients with NF155⁺ CIDP/CCPD have one of two specific human leukocyte antigen (HLA) haplotypes, which results in a significantly higher prevalence of HLA-DRB1 ^* 15:01-DQB1 ^* 06:02 compared with healthy Japanese controls. This indicates an involvement of specific HLA class II molecules and relevant T cells in addition to IgG4 anti-NF155 antibodies in the mechanism underlying IgG4 NF155⁺ CIDP/CCPD.

Reassessing IVIg therapy in chronic inflammatory demyelinating polyradiculoneuropathy during COVID-19: a chance to verify the need for chronic maintenance therapy

The outbreak of a severe acute respiratory syndrome caused by a novel coronavirus (COVID-19), has raised health concerns for patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), who are frequently on long-term immunotherapies. Treatment with IVIg does not increase the risk of contracting COVID-19, and the IVIg administration may have a protective role. However, infusions can expose patients to an increased risk of contracting SARS-CoV-2 due to repeated access to Health Facilities. In this report we analyzed the short-term follow-up of CIDP patients who modified their chronic IVIg therapy during pandemic. About half of CIDP patients regularly treated with IVIg tried to stop treatment and about 10% shifted to SCIg. Forty-two percent of the patients who stopped the treatment reported a clinical deterioration after suspension and had to restart IVIg. This study demonstrated that in selected cases it is possible to successfully stop the chronic IVIg treatment, even in patients who have been treated for several years.

Randomized trial of intravenous immunoglobulin maintenance treatment regimens in chronic inflammatory demyelinating polyradiculoneuropathy

Background and purpose

High peak serum immunoglobulin G (IgG) levels may not be needed for maintenance intravenous immunoglobulin (IVIg) treatment in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and such high levels may cause side effects. More frequent lower dosing may lead to more stable IgG levels and higher trough levels, which might improve efficacy. The aim of this trial is to investigate whether high frequent low dosage IVIg treatment is more effective than low frequent high dosage IVIg treatment.

Methods

In this randomized placebo‐controlled crossover trial, we included patients with CIDP proven to be IVIg‐dependent and receiving an individually established stable dose and interval of IVIg maintenance treatment. In the control arm, patients received their individual IVIg dose and interval followed by a placebo infusion at half the interval. In the intervention arm, patients received half their individual dose at half the interval. After a wash‐out phase patients crossed over. The primary outcome measure was handgrip strength (assessed using a Martin Vigorimeter). Secondary outcome indicators were health‐related quality of life (36‐item Short‐Form Health Survey), disability (Inflammatory Rasch‐built Overall Disability Scale), fatigue (Rasch‐built Fatigue Severity Scale) and side effects.

Results

Twenty‐five patients were included and were treated at baseline with individually adjusted dosages of IVIg ranging from 20 to 80 g and intervals ranging from 14 to 35 days. Three participants did not complete the trial; the main analysis was therefore based on the 22 patients completing both treatment periods. There was no significant difference in handgrip strength change from baseline between the two treatment regimens (coefficient −2.71, 95% CI −5.4, 0.01). Furthermore, there were no significant differences in any of the secondary outcomes or side effects.

Conclusions

More frequent lower dosing does not further improve the efficacy of IVIg in stable IVIg‐dependent CIDP and does not result in fewer side effects.

Outcome measures for chronic inflammatory demyelinating polyneuropathy in research: relevance and applicability to clinical practice

Outcome measures are recommended in the management of chronic inflammatory demyelinating polyneuropathy (CIDP). Various scales have been proposed in recent years, some now commonly utilized in daily clinical practice. The available evidence base relies itself on randomized controlled trial data obtained over the past 30 years, with several studies using different primary and secondary outcomes. We here review the different outcome measures used in CIDP research in relation to those currently recommended for clinical management. We consider the evidence base for CIDP treatment from the primary and secondary outcomes used in these studies and attempt to assess how this may relate to current clinical practice of routine evaluation of treatment effects and long-term monitoring.

Expanding the Role of the Pharmacist: Immunoglobulin Therapy and Disease Management in Neuromuscular Disorders

Immunoglobulin G (IgG) is a commonly used treatment for chronic neuromuscular disorders (NMDs), such as chronic inflammatory demyelinating polyneuropathy and multifocal motor neuropathy. IgG therapy has also shown promise in treating other NMDs including myasthenia gravis, polymyositis, and dermatomyositis. IgG is administered as either intravenous immunoglobulin (IVIg) or subcutaneous immunoglobulin (SCIg), with SCIg use becoming more popular due to the treatment burden associated with IVIg. IVIg requires regular venous access; long infusions (typically 4-6 hours); and can result in systemic adverse events (AEs) for some patients. In contrast, SCIg can be self-administered at home with shorter infusions (approximately 1 hour) and fewer systemic AEs. As patient care shifts toward home-based settings, the role of the pharmacist is paramount in providing a continuation of care and acting as the bridge between patient and clinic. Pharmacists with a good understanding of current recommendations, dosing strategies, and administration routes for IgG therapy are best placed to support patients. The aims of this review are to highlight the evidence supporting IgG therapy in the treatment of NMDs and provide practical information on patient management and IVIg/SCIg dosing in order to guide pharmacists on optimizing clinical outcomes and patient care.

Systematic literature review of burden of illness in chronic inflammatory demyelinating polyneuropathy (CIDP)

Background

Chronic inflammatory demyelinating polyneuropathy (CIDP) is a rare neurological disorder characterised by muscle weakness and impaired sensory function. The present study provides a comprehensive literature review of the burden of illness of CIDP.

Methods

Systematic literature search of PubMed, Embase, and key conferences in May 2019. Search terms identified studies on the epidemiology, humanistic burden, current treatment, and economic burden of CIDP published since 2009 in English.

Results

Forty-five full texts and nineteen conference proceedings were identified on the epidemiology (n = 9), humanistic burden (n = 7), current treatment (n = 40), and economic burden (n = 8) of CIDP. Epidemiological studies showed incidence and prevalence of 0.2–1.6 and 0.8–8.9 per 100,000, respectively, depending on geography and diagnostic criteria. Humanistic burden studies revealed that patients experienced physical and psychosocial burden, including impaired physical function, pain and depression. Publications on current treatments reported on six main types of therapy: intravenous immunoglobulins, subcutaneous immunoglobulins, corticosteroids, plasma exchange, immunosuppressants, and immunomodulators. Treatments may be burdensome, due to adverse events and reduced independence caused by treatment administration setting. In Germany, UK, France, and the US, CIDP economic burden was driven by direct costs of treatment and hospitalisation. CIDP was associated with indirect costs driven by impaired productivity.

Conclusions

This first systematic review of CIDP burden of illness demonstrates the high physical and psychosocial burden of this rare disease. Future research is required to fully characterise the burden of CIDP, and to understand how appropriate treatment can mitigate burden for patients and healthcare systems.

Electronic supplementary material

The online version of this article (10.1007/s00415-020-09998-8) contains supplementary material, which is available to authorized users.

Progress in Hematopoietic Stem Cell Transplantation for CIDP

Chronic inflammatory demyelinating polyneuropathy (CIDP) is a kind of autoimmune-mediated inflammation and demyelinating disease. The etiology is mainly related to autoimmune dysfunction. The conventional treatments of CIDP have relied on immunomodulation and inhibition therapies such as adrenal cortex hormone, intravenous immunoglobulin (IVIg) and plasma exchange. Hematopoietic stem cell transplantation (HSCT) is known as a novel therapy for autoimmune disorders, which provides the chance to cure CIDP. More than 70 patients with refractory CIDP have received HSCT. The clinical symptoms and electrophysiological examination results of most patients have been improved. However, the treatment still has risks. This review describes the pathogenesis of CIDP and the current conventional treatments, and highlights the application of HSCT in CIDP, including its efficacy and safety.

Neurological autoimmune disorders with prominent gastrointestinal manifestations: A review of presentation, evaluation, and treatment

BACKGROUND

The identification of autoantibodies directed against neuronal antigens has led to the recognition of a wide spectrum of neurological autoimmune disorders (NAD). With timely recognition and treatment, many patients with NAD see rapid improvement. Symptoms associated with NAD can be diverse and are determined by the regions of the nervous system affected. In addition to neurological symptoms, a number of these disorders present with prominent gastrointestinal (GI) manifestations such as nausea, diarrhea, weight loss, and gastroparesis prompting an initial evaluation by gastroenterologists.

PURPOSE

This review provides a general overview of autoantibodies within the nervous system, focusing on three scenarios in which nervous system autoimmunity may initially present with gut symptoms. A general approach to evaluation and treatment, including antibody testing, will be reviewed.

Chronic inflammatory demyelinating polyneuropathy: update on diagnosis, immunopathogenesis and treatment

Chronic inflammatory demyelinating polyneuropathy (CIDP) is an immune-mediated neuropathy typically characterised by symmetrical involvement, and proximal as well as distal muscle weakness (typical CIDP). However, there are several 'atypical' subtypes, such as multifocal acquired demyelinating sensory and motor neuropathy (Lewis-Sumner syndrome) and 'distal acquired demyelinating symmetric neuropathy', possibly having different immunopathogenesis and treatment responses. In the absence of diagnostic and pathogenetic biomarkers, diagnosis and treatment may be difficult, but recent progress has been made in the application of neuroimaging tools demonstrating nerve hypertrophy and in identifying subgroups of patients who harbour antibodies against nodal proteins such as neurofascin and contactin-1. Despite its relative rarity, CIDP represents a significant economic burden, mostly due to costly treatment with immunoglobulin. Recent studies have demonstrated the efficacy of subcutaneous as well as intravenous immunoglobulin as maintenance therapy, and newer immunomodulating drugs can be used in refractory cases. This review provides an overview focusing on advances over the past several years.

Efficacy and Tolerability of Intravenous Immunoglobulin and Subcutaneous Immunoglobulin in Neurologic Diseases

PURPOSE

IV immunoglobulin (Ig) therapy has been widely used for the treatment of neurologic disorders, autoimmune diseases, immunodeficiency-related diseases, blood system diseases, and cancers. In this review, we summarize the efficacy and tolerability of IVIg and SCIg therapy in neurologic diseases.

METHODS

We summarized and analyzed the efficacy and tolerability of IVIg and SCIg in neurologic diseases, by analyzing the literature pertaining to the use of IVIg and SCIg to treat nervous system diseases.

FINDINGS

In clinical neurology practice, IVIg has been shown to be useful for the treatment of new-onset or recurrent immune diseases and for long-term maintenance treatment of chronic diseases. Moreover, IVIg may have applications in the management of intractable autoimmune epilepsy, paraneoplastic syndrome, autoimmune encephalitis, and neuromyelitis optica. SCIg is emerging as an alternative to IVIg treatment. Although SCIg has a composition similar to that of IVIg, the applications of this therapy are different. Notably, the bioavailability of SCIg is lower than that of IVIg, but the homeostasis level is more stable. Current studies have shown that these 2 therapies have pharmacodynamic equivalence.

IMPLICATIONS

In this review, we explored the efficacy of IVIg in the treatment of various neurologic disorders. IVIg administration still faces many challenges. Thus, it will be necessary to standardize the use of IVIg in the clinical setting. SCIg administration is a novel and feasible treatment option for neurologic and immune-related diseases, such as chronic inflammatory demyelinating polyradiculoneuropathy and idiopathic inflammatory myopathies. As our understanding of the mechanisms of action of IVIg improve, potential next-generation biologics can being developed.

Efficacy and Safety of Octagam® in Patients With Chronic Inflammatory Demyelinating Polyneuropathy

Introduction

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a debilitating autoimmune neuropathy that is treated with intravenous immunoglobulin (IVIG). The aim of this retrospective study was to investigate the efficacy and safety of the sucrose-free IVIG Octagam® (Octapharma AG, Lachen, Switzerland) in patients with CIDP.

Methods

Data from 47 patients who received at least one dose of Octagam were collected from the records of 11 centres in France. Efficacy was assessed using Overall Neuropathy Limitation Scale (ONLS). Safety was evaluated using adverse event rates.

Results

Data from 24 patients who were IVIG naïve (n = 11) or had stopped IVIG ≥ 12 weeks before   initiation of Octagam therapy (washout group; n  = 13) were included in the efficacy analysis. At 4 months post-initiation of Octagam treatment, 41.7% of patients had improved their functional status (decrease of ≥ 1 ONLS score) with a significant change   in the ONLS score from baseline (– 0.42; p = 0.04; signed test). Functional status was reduced in only two patients: one patient in the IVIG-naïve group and one patient in the IVIG-washout group. All 47 patients were included in the safety analysis, which showed that Octagam was well tolerated, with a frequency of 0.04 adverse events per Octagam course. The most common adverse drug reaction was headache.

Conclusions

These real-life results are consistent with the efficacy and safety of IVIG reported in randomised controlled studies. A long-term prospective study of Octagam in patients with CIDP is warranted.

Funding

Octapharma, France SAS.

Efficacy and safety of IVIG in CIDP: Combined data of the PRIMA and PATH studies

Intravenous immunoglobulin (IVIG) is a potential therapy for chronic inflammatory demyelinating polyneuropathy (CIDP). To investigate the efficacy and safety of the IVIG IgPro10 (Privigen) for treatment of CIDP, results from Privigen Impact on Mobility and Autonomy (PRIMA), a prospective, open‐label, single‐arm study of IVIG in immunoglobulin (Ig)‐naïve or IVIG pre‐treated subjects (NCT01184846, n = 28) and Polyneuropathy And Treatment with Hizentra (PATH), a double‐blind, randomized study including an open‐label, single‐arm IVIG phase in IVIG pre‐treated subjects (NCT01545076, IVIG restabilization phase n = 207) were analyzed separately and together (n = 235). Efficacy assessments included change in adjusted inflammatory neuropathy cause and treatment (INCAT) score, grip strength and Medical Research Council (MRC) sum score. Adverse drug reactions (ADRs) and ADRs/infusion were recorded. Adjusted INCAT response rate was 60.7% in all PRIMA subjects at Week 25 (76.9% in IVIG pre‐treated subjects) and 72.9% in PATH. In the pooled cohort (n = 235), INCAT response rate was 71.5%; median time to INCAT improvement was 4.3 weeks. No clear demographic differences were noticed between early (responding before Week 7, n = 148) and late responders (n = 21). In the pooled cohort, median change from baseline to last observation was −1.0 (interquartile range −2.0; 0.0) point for INCAT score; +8.0 (0.0; 20.0) kPa for maximum grip strength; +3.0 (1.0; 7.0) points for MRC sum score. In the pooled cohort, 271 ADRs were reported in 105 subjects (44.7%), a rate of 0.144 ADRs per infusion. This analysis confirms the efficacy and safety of IgPro10, a recently FDA‐approved IVIG for CIDP, in a population of mainly pre‐treated subjects with CIDP [Correction added on 14 March 2019 after first online publication: the INCAT response rate has been corrected.].

Clinical and economic comparison of an individualised immunoglobulin protocol vs. standard dosing for chronic inflammatory demyelinating polyneuropathy

Background

The clinical and economic implications of an individualised intravenous immunoglobulin (IVIg) protocol for chronic inflammatory demyelinating polyneuropathy (CIDP) are unknown. Comparison with standard dosing regimens has not been performed.

Methods

We retrospectively studied 47 IVIg-treated subjects with CIDP over 4 years with an individualised, outcome-measured, dose-modifying protocol. We evaluated responder and remission rates, clinical improvement levels and dose requirements. We compared clinical benefits and costs with those reported with standard dosing at 1 g/kg every 3 weeks.

Results

The IVIg-responder rate was 83% and the 4-year remission rate was 25.6%. Mean IVIg dose requirements were 22.06 g/week (SD:15.29) in patients on ongoing therapy. Dose range was wide (5.83–80 g/week). Mean infusion frequency was every 4.34 weeks (SD:1.70) and infusion duration of 2.79 days (SD:1.15). Mean Overall Neuropathy Limitation Scale improvement was 2.54 (SD:1.89) and mean MRC sum score improvement of 12.23 (SD:7.17) in IVIg-responders. Mean modified-INCAT (Inflammatory Neuropathy Cause and Treatment) score improvement was similar (p = 0.47) and mean MRC sum score improvement greater (p < 0.001) in our cohort, compared to the IVIg-treated arm of the ICE Study. Mean drug costs were GBP 37,660/patient/year (€ 43,309) and mean infusion-related costs of GBP 17,115/patient/year (€ 19,682), totalling GBP 54,775/patient/year (€ 62,991). Compared to standard dosing using recorded weight, mean savings were of GBP 13,506/patient/year (€ 15,532). Compared to standard dosing using dosing weight, savings were of GBP 6,506/patient/year (€ 7,482).

Conclusion

Our results indicate that an individualised IVIg treatment protocol is clinically non-inferior and 10–25% more cost-effective than standard dosing regimens in CIDP.

POEMS syndrome: clinical update

POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, M-protein, skin changes) is a rare paraneoplastic syndrome, caused by a plasma cell proliferative disorder, which is most commonly lambda restricted. The neurological hallmark, which forms one of the mandatory criteria for diagnosis, is a subacute onset demyelinating neuropathy, which can be rapidly disabling and painful. A number of multi-system features are also characteristic of this disorder, and certainly not restricted to those included in its acronym, which though limited, remains a useful and memorable name, helping distinguish POEMS syndrome from other paraproteinaemic neuropathies. The discovery of vascular endothelial growth factor (VEGF) in association with POEMS syndrome has been extremely useful in aiding clinical diagnosis, and monitoring response to treatment, as well as helping understand the underlying mechanism of disease. Interestingly, however, treatment targeting VEGF has been disappointing, suggesting other disease mechanisms or inflammatory processes are also important. Current understanding of the pathogenesis of POEMS syndrome is outlined in detail in the accompanying article by Cerri et al. Here, we review the clinical features of POEMS syndrome, differential diagnosis and available treatment options, based on current literature.

Reversing Autoimmunity Combination of Rituximab and Intravenous Immunoglobulin

In this concept paper, the authors present a unique and novel protocol to treat autoimmune diseases that may have the potential to reverse autoimmunity. It uses a combination of B cell depletion therapy (BDT), specifically rituximab (RTX) and intravenous immunoglobulin (IVIg), based on a specifically designed protocol (Ahmed Protocol). Twelve infusions of RTX are given in 6–14 months. Once the CD20⁺ B cells are depleted from the peripheral blood, IVIg is given monthly until B cells repopulation occurs. Six additional cycles are given to end the protocol. During the stages of B cell depletion, repopulation and after clinical recovery, IVIg is continued. Along with clinical recovery, significant reduction and eventual disappearance of pathogenic autoantibody occurs. Administration of IVIg in the post-clinical period is a crucial part of this protocol. This combination reduces and may eventually significantly eliminates inflammation in the microenvironment and facilitates restoring immune balance. Consequently, the process of autoimmunity and the phenomenon that lead to autoimmune disease are arrested, and a sustained and prolonged disease and drug-free remission is achieved. Data from seven published studies, in which this combination protocol was used, are presented. It is known that BDT does not affect check points. IVIg has functions that mimic checkpoints. Hence, when inflammation is reduced and the microenvironment is favorable, IVIg may restore tolerance. The authors provide relevant information, molecular mechanism of action of BDT, IVIg, autoimmunity, and autoimmune diseases. The focus of the manuscript is providing an explanation, using the current literature, to demonstrate possible pathways, used by the combination of BDT and IVIg in providing sustained, long-term, drug-free remissions of autoimmune diseases, and thus reversing autoimmunity, albeit for the duration of the observation.

Intravenous immunoglobulin for maintenance treatment of multifocal motor neuropathy: A multi-center, open-label, 52-week phase 3 trial

Intravenous immunoglobulin (IVIg) therapy is currently the only established treatment in patients with multifocal motor neuropathy (MMN), and many patients have an IVIg-dependent fluctuation. We aimed to investigate the efficacy and safety of every 3 week IVIg (1.0 g/kg) for 52 weeks. This study was an open-label phase 3 clinical trial, enrolling 13 MMN patients. After an induction IVIg therapy (0.4 g/kg/d for 5 consecutive days), maintenance dose (1.0 g/kg) was given every 3 weeks for 52 weeks. The major outcome measures were the Medical Research Council (MRC) sum score and hand-grip strength at week 52. This trial is registered with ClinicalTrials.gov, number NCT01827072. At week 52, 11 of the 13 patients completed the study, and all 11 had a sustained improvement. The mean (SD) MRC sum score was 85.6 (8.7) at the baseline, and 90.6 (12.8) at week 52. The mean grip strength was 39.2 (30.0) kPa at the baseline and 45.2 (32.8) kPa at week 52. Two patients dropped out because of adverse event (dysphagia) and decision of an investigator, respectively. Three patients developed coronary spasm, dysphagia, or inguinal herniation, reported as the serious adverse events, but considered not related with the study drug. The other adverse effects were mild and resolved by the end of the study period. Our results show that maintenance treatment with 1.0 g/kg IVIg every 3 week is safe and efficacious for MMN patients up to 52 weeks. Further studies are required to investigate optimal dose and duration of maintenance IVIg for MMN.