Subcutaneous immunoglobulin for maintenance treatment in chronic inflammatory demyelinating polyneuropathy (PATH): a randomised, double-blind, placebo-controlled, phase 3 trial

Chronic Inflammatory Demyelinating Polyradiculoneuropathy in Association With Concomitant Diseases: Identification and Management

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a rare, heterogeneous, but treatable autoimmune-mediated peripheral neuropathy characterized by demyelination. CIDP can occur independently or simultaneously with a variety of diseases such as diabetes, monoclonal gammopathy of undetermined significance (MGUS), connective tissue disease, and HIV. It is important to identify CIDP and specific peripheral neuropathies caused by these diseases; this review aims to summarize the CIDP literatures related to diabetes, MGUS, SLE, and HIV, and to be helpful for the management of such patients.

Neuroimmune disorders in COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the aetiologic agent of the coronavirus disease 2019 (COVID-19), is now rapidly disseminating throughout the world with 147,443,848 cases reported so far. Around 30-80% of cases (depending on COVID-19 severity) are reported to have neurological manifestations including anosmia, stroke, and encephalopathy. In addition, some patients have recognised autoimmune neurological disorders, including both central (limbic and brainstem encephalitis, acute disseminated encephalomyelitis [ADEM], and myelitis) and peripheral diseases (Guillain-Barré and Miller Fisher syndrome). We systematically describe data from 133 reported series on the Neurology and Neuropsychiatry of COVID-19 blog ( https://blogs.bmj.com/jnnp/2020/05/01/the-neurology-and-neuropsychiatry-of-covid-19/ ) providing a comprehensive overview concerning the diagnosis, and treatment of patients with neurological immune-mediated complications of SARS-CoV-2. In most cases the latency to neurological disorder was highly variable and the immunological or other mechanisms involved were unclear. Despite specific neuronal or ganglioside antibodies only being identified in 10, many had apparent responses to immunotherapies. Although the proportion of patients experiencing immune-mediated neurological disorders is small, the total number is likely to be underestimated. The early recognition and improvement seen with use of immunomodulatory treatment, even in those without identified autoantibodies, makes delayed or missed diagnoses risk the potential for long-term disability, including the emerging challenge of post-acute COVID-19 sequelae (PACS). Finally, potential issues regarding the use of immunotherapies in patients with pre-existent neuro-immunological disorders are also discussed.

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.

Epidemiology of chronic inflammatory demyelinating polyradiculoneuropathy in The Netherlands

BACKGROUND AND AIMS

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a rare but disabling disorder that often requires long-term immunomodulatory treatment. Background incidence rates and prevalence and risk factors for developing CIDP are still poorly defined. In the current study, we used a longitudinal population-based cohort study in The Netherlands to assess these rates and demographic factors and comorbidity associated with CIDP.

METHODS

We determined the incidence rate and prevalence of CIDP between 2008-2017 and the occurrence of potential risk factors in a retrospective Dutch cohort study using the Integrated Primary Care Information (IPCI) database. Cases were defined as CIDP if the diagnosis of CIDP was described in the electronic medical file.

RESULTS

In a source population of 928,030 persons with a contributing follow-up of 3,525,686 person-years, we identified 65 patients diagnosed with CIDP. The overall incidence rate was 0.68 per 100,000 person-years (95% CI 0.45-0.99). The overall prevalence was 7.00 per 100,000 individuals (95% CI 5.41-8.93). The overall incidence rate was higher in men compared to woman (IRR 3.00, 95% CI 1.27-7.11), and higher in elderly of 50 years or older compared to people <50 years of age (IRR 17 95% CI 4-73). Twenty percent of CIDP cases had DM and 9% a co-existing other autoimmune disease.

INTERPRETATION

These background rates are important to monitor changes in the frequency of CIDP following infectious disease outbreaks identify potential risk factors, and to estimate the social and economic burden of CIDP.

Association of Maintenance Intravenous Immunoglobulin With Prevention of Relapse in Adult Myelin Oligodendrocyte Glycoprotein Antibody-Associated Disease

Importance

Recent studies suggest that maintenance intravenous immunoglobulin (IVIG) may be an effective treatment to prevent relapses in myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD); however, most of these studies had pediatric cohorts, and few studies have evaluated IVIG in adult patients.

Objective

To determine the association of maintenance IVIG with the prevention of disease relapse in a large adult cohort of patients with MOGAD.

Design, Setting, and Participants

This was a retrospective cohort study conducted from January 1, 2010, to October 31, 2021. Patients were recruited from 14 hospitals in 9 countries and were included in the analysis if they (1) had a history of 1 or more central nervous system demyelinating attacks consistent with MOGAD, (2) had MOG-IgG seropositivity tested by cell-based assay, and (3) were age 18 years or older when starting IVIG treatment. These patients were retrospectively evaluated for a history of maintenance IVIG treatment.

Exposures

Maintenance IVIG.

Main Outcomes and Measures

Relapse rates while receiving maintenance IVIG compared with before initiation of therapy.

Results

Of the 876 adult patients initially identified with MOGAD, 59 (median [range] age, 36 [18-69] years; 33 women [56%]) were treated with maintenance IVIG. IVIG was initiated as first-line immunotherapy in 15 patients (25%) and as second-line therapy in 37 patients (63%) owing to failure of prior immunotherapy and in 7 patients (12%) owing to intolerance to prior immunotherapy. The median (range) annualized relapse rate before IVIG treatment was 1.4 (0-6.1), compared with a median (range) annualized relapse rate while receiving IVIG of 0 (0-3) (t108 = 7.14; P < .001). Twenty patients (34%) had at least 1 relapse while receiving IVIG with a median (range) time to first relapse of 1 (0.03-4.8) years, and 17 patients (29%) were treated with concomitant maintenance immunotherapy. Only 5 of 29 patients (17%) who received 1 g/kg of IVIG every 4 weeks or more experienced disease relapse compared with 15 of 30 patients (50%) treated with lower or less frequent dosing (hazard ratio, 3.31; 95% CI, 1.19-9.09; P = .02). At final follow-up, 52 patients (88%) were still receiving maintenance IVIG with a median (range) duration of 1.7 (0.5-9.9) years of therapy. Seven of 59 patients (12%) discontinued IVIG therapy: 4 (57%) for inefficacy, 2 (29%) for adverse effects, and 1 (14%) for a trial not receiving therapy after a period of disease inactivity.

Conclusions and Relevance

Results of this retrospective, multicenter, cohort study of adult patients with MOGAD suggest that maintenance IVIG was associated with a reduction in disease relapse. Less frequent and lower dosing of IVIG may be associated with treatment failure. Future prospective randomized clinical trials are warranted to confirm these findings.

Chronic Inflammatory Demyelinating Polyneuropathy (CIDP): Current Therapies and Future Approaches

Chronic inflammatory demyelinating polyneuropathy (CIDP) is an acquired immune-mediated polyradiculoneuropathy leading to disability via inflammatory demyelination of peripheral nerves. Various therapeutic approaches with different mechanisms of action are established for the treatment of CIDP. Of those, corticosteroids, intravenous or subcutaneous immunoglobulin, or plasma exchange are established first-line therapies as suggested by the recently revised EAN/PNS guidelines for the management of CIDP. In special cases, immunosuppressants or rituximab may be used. Novel therapeutic approaches currently undergoing clinical studies include molecules or monoclonal antibodies interacting with Fc receptors on immune cells to alleviate immune-mediated neuronal damage. Despite various established therapies and the current development of novel therapeutics, treatment of CIDP remains challenging due to an inter-individually heterogeneous disease course and the lack of surrogate parameters to predict the risk of clinical deterioration.

Analysis of Relapse by Inflammatory Rasch-built Overall Disability Scale Status in the PATH Study of Subcutaneous Immunoglobulin in Chronic Inflammatory Demyelinating Polyneuropathy

Clinical trials in chronic inflammatory demyelinating polyneuropathy (CIDP) often assess efficacy using the ordinal Inflammatory Neuropathy Cause and Treatment (INCAT) disability score. Here, data from the PATH study was reanalyzed using change in Inflammatory Rasch‐built Overall Disability Scale (I‐RODS) to define CIDP relapse instead of INCAT. The PATH study comprised an intravenous immunoglobulin (IVIG) dependency period and an IVIG (IgPro10 [Privigen]) restabilization period; subjects were then randomized to weekly maintenance subcutaneous immunoglobulin (SCIG; IgPro20 [Hizentra]) 0.2 g/kg or 0.4 g/kg or placebo for 24 weeks. CIDP relapse was defined as ≥1‐point deterioration in adjusted INCAT, with a primary endpoint of relapse or withdrawal rates. This retrospective exploratory analysis redefined relapse using I‐RODS via three different cut‐off methods: an individual variability method, fixed cut‐off of ≥8‐point deterioration on I‐RODS centile score or ≥4‐point deterioration on I‐RODS raw score. Relapse or withdrawal rates were 47% for placebo, 34% for 0.2 g/kg IgPro20 and 19% for 0.4 g/kg IgPro20 using the raw score; 40%, 28% and 15%, respectively using the centile score, and 49%, 40% and 27%, respectively using the individual variability method. IgPro20 was shown to be efficacious as a maintenance therapy for CIDP when relapse was defined using I‐RODS. A stable response pattern was shown for I‐RODS across various applied cut‐offs, which could be applied in future clinical trials.

Withdrawal of intravenous immunoglobulin in chronic inflammatory demyelinating polyradiculoneuropathy

Intravenous immunoglobulins are an efficacious treatment for chronic inflammatory demyelinating polyradiculoneuropathy. Biomarkers for disease activity are lacking, making the need for ongoing treatment difficult to assess, leading to potential overtreatment and high health-care costs. Our objective was to determine whether intravenous immunoglobulin withdrawal is non-inferior to continuing intravenous immunoglobulin treatment and to determine how often patients are overtreated.

We performed a randomized, double-blind, intravenous immunoglobulin-controlled non-inferiority trial in seven centres in the Netherlands (Trial registration: ISRCTN 13637698; www.isrctn.com/ISRCTN13637698). Adults with clinically stable chronic inflammatory demyelinating polyradiculoneuropathy using intravenous immunoglobulin maintenance treatment for at least 6 months were included. Patients received either intravenous immunoglobulin withdrawal (placebo) as investigational treatment or continuation of intravenous immunoglobulin treatment (control). The primary outcome was the mean change in logit scores from baseline to 24-week follow-up on the patient-reported Inflammatory Rasch–Overall Disability Scale. The non-inferiority margin was predefined as between-group difference in mean change scores of −0.65. Patients who deteriorated could reach a relapse end point according to predefined criteria. Patients with a relapse end point after intravenous immunoglobulin withdrawal entered a restabilization phase. All patients from the withdrawal group who remained stable were included in an open-label extension phase of 52 weeks.

We included 60 patients, of whom 29 were randomized to intravenous immunoglobulin withdrawal and 31 to continuation of treatment. The mean age was 58 years (SD 14.7) and 67% was male. The between-group difference in mean change Inflammatory Rasch–Overall Disability Scale scores was −0.47 (95% CI −1.24 to 0.31), indicating that non-inferiority of intravenous immunoglobulin withdrawal could not be established. In the intravenous immunoglobulin withdrawal group, 41% remained stable for 24 weeks, compared to 58% in the intravenous immunoglobulin continuation group (−17%; 95% CI −39 to 8). Of the intravenous immunoglobulin withdrawal group, 28% remained stable at the end of the extension phase. Of the patients in the restabilization phase, 94% restabilized within 12 weeks.

In conclusion, it remains inconclusive whether intravenous immunoglobulin withdrawal is non-inferior compared to continuing treatment, partly due to larger than expected confidence intervals leading to an underpowered study. Despite these limitations, a considerable proportion of patients could stop treatment and almost all patients who relapsed were restabilized quickly. Unexpectedly, a high proportion of intravenous immunoglobulin-treated patients experienced a relapse end point, emphasizing the need for more objective measures for disease activity in future trials, as the patient-reported outcome measures might not have been able to identify true relapses reliably. Overall, this study suggests that withdrawal attempts are safe and should be performed regularly in clinically stable patients.

Chronic Inflammatory Demyelinating Polyradiculoneuropathy: Five New Things

Chronic Inflammatory Demyelinating Polyradiculoneuropathy (CIDP), while rare and heterogeneous, is one of the most common immune mediated neuropathies. CIDP, however, especially CIDP variants, can be difficult to diagnose. (1) There is no gold standard testing for CIDP, and, while a few specific disease-associated antibodies have been described, these are absent in the majority of patients. Furthermore, many experts consider the presence of these antibodies to be indicative of a separate disease. (2) Ultimately, CIDP remains a diagnosis of exclusion. Mimics are ruled out either by history or additional ancillary testing. Following experts’ guidelines on the diagnosis of CIDP increases significantly the accuracy of diagnosis. On a different note, while most patients with CIDP respond well to treatment, some may not tolerate therapy, and other may be refractory to first line treatments. In this review, we discuss 5 new things related to CIDP: 1) the updated European Academy of Neurology/Peripheral Nerve Society (EAN/PNS) CIDP guidelines, 2) the expansion of the Chronic Immune Sensory Polyradiculopathy (CISP) spectrum, 3) updates in therapy for CIDP, 4) antibodies testing, serum neurofilament light chain and their role, and 5) disorders that can mimic CIDP.

CIDP: Current Treatments and Identification of Targets for Future Specific Therapeutic Intervention

Chronic inflammatory demyelinating polyneuropathy (CIDP) is an acquired immune-mediated inflammatory disorder of the peripheral nervous system. This clinically heterogeneous neurological disorder is closely related to Guillain–Barré syndrome and is considered the chronic counterpart of that acute disease. Currently available treatments are mostly empirical; they include corticosteroids, intravenous immunoglobulins, plasma exchange and chronic immunosuppressive agents, either alone or in combination. Recent advances in the understanding of the underlying pathogenic mechanisms in CIDP have brought a number of novel ways of possible intervention for use in CIDP. This review summarizes selected pre-clinical and clinical findings, highlights the importance of using adapted animal models to evaluate the efficacy of novel treatments, and proposes the outlines of future directions to ameliorate the conditions of patients with CIDP.

Randomized trial of three IVIg doses for treating chronic inflammatory demyelinating polyneuropathy

Intravenous immunoglobulin treatment for chronic inflammatory demyelinating polyneuropathy usually starts with a 2.0 g/kg induction dose followed by 1.0 g/kg maintenance doses every 3 weeks. No dose-ranging studies with intravenous immunoglobulin maintenance therapy have been published.

The Progress in Chronic Inflammatory Demyelinating polyneuropathy (ProCID) study was a prospective, double-blind, randomized, parallel-group, multicentre, phase III study investigating the efficacy and safety of 10% liquid intravenous immunoglobulin (Panzyga^®) in patients with active chronic inflammatory demyelinating polyneuropathy. Patients were randomized 1:2:1 to receive the standard intravenous immunoglobulin induction dose and then either 0.5, 1.0 or 2.0 g/kg maintenance doses every 3 weeks. The primary end point was the response rate in the 1.0 g/kg group, defined as an improvement ≥1 point in adjusted Inflammatory Neuropathy Cause and Treatment score at Week 6 versus baseline and maintained at Week 24. Secondary end points included dose response and safety. This trial was registered with EudraCT (Number 2015–005443-14) and clinicaltrials.gov (NCT02638207).

Between August 2017 and September 2019, the study enrolled 142 patients. All 142 were included in the safety analyses. As no post-infusion data were available for three patients, 139 were included in the efficacy analyses, of whom 121 were previously on corticosteroids. The response rate was 80% (55/69 patients) [95% confidence interval (CI): 69–88%] in the 1.0 g/kg group, 65% (22/34; CI: 48–79%) in the 0.5 g/kg group, and 92% (33/36; CI: 78–97%) in the 2.0 g/kg group. While the proportion of responders was higher with higher maintenance doses, logistic regression analysis showed that the effect on response rate was driven by a significant difference between the 0.5 and 2.0 g/kg groups, whereas the response rates in the 0.5 and 2.0 g/kg groups did not differ significantly from the 1.0 g/kg group. Fifty-six per cent of all patients had an adjusted Inflammatory Neuropathy Cause and Treatment score improvement 3 weeks after the induction dose alone. Treatment-related adverse events were reported in 16 (45.7%), 32 (46.4%) and 20 (52.6%) patients in the 0.5, 1.0 and 2.0 g/kg dose groups, respectively. The most common adverse reaction was headache. There were no treatment-related deaths.

Intravenous immunoglobulin (1.0 g/kg) was efficacious and well tolerated as maintenance treatment for patients with chronic inflammatory demyelinating polyneuropathy. Further studies of different maintenance doses of intravenous immunoglobulin in chronic inflammatory demyelinating polyneuropathy are warranted.

Safety of conventional immunosuppressive therapies for patients with dermatological conditions and coronavirus disease 2019: A review of current evidence

The effect of coronavirus disease 2019 (COVID-19) on patients receiving conventional immunosuppressive (IS) therapy has yet to be fully determined; however, research on using IS therapy for treating COVID-19 in acutely ill patients is increasing. While some believe that IS therapy may be protective, others argue that these agents may make patients more susceptible to COVID-19 infection and morbidity and advocate for a more cautious, individualized approach to determining continuation, reduction, or discontinuation of therapy. In this review, we aim to provide an overview of COVID-19 risk in dermatological patients who are receiving conventional IS therapies, including mycophenolate mofetil, methotrexate, cyclosporine, azathioprine, apremilast, JAK inhibitors, and systemic steroids. Additionally, we provide recommendations for management of these medications for dermatological patients during the COVID-19 pandemic. Treatment of dermatological disease during the COVID-19 pandemic should involve shared decision-making between the patient and provider, with consideration of each patient's comorbidities and the severity of the patient's dermatological disease.

Predicting long-term trends in inflammatory neuropathy outcome measures using latent class modelling

BACKGROUND

Immunoglobulin (Ig) is used to treat chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and multifocal motor neuropathy with conduction block (MMNCB). Regular infusions may be used for symptom control. Disease activity is monitored with clinical outcome measurements. We examined outcome measure variation during clinically stable periods in Ig-treated CIDP and MMNCB patients. We explored utility of serial outcome measurement in long-term outcome prediction.

METHODS

Retrospective longitudinal analysis of a single neuroscience centre's Ig-treated CIDP and MMNCB patients, 2009-2020, was performed. Mean and percentage change for grip strength, Rasch-built overall disability scales (RODS) and MRC sum scores (MRC-SS) during periods of clinical stability were compared to score-specific minimal clinically important differences (MCID). Latent class mixed modelling (LCMM) was used to identify longitudinal trends and factors influencing long-term outcome.

RESULTS

We identified 85 CIDP and 23 MMNCB patients (1,423 datapoints; 5635 treatment-months). Group-averaged outcome measures varied little over time. Intra-individual variation exceeded MCID for RODS in 44.2% CIDP and 16.7% MMNCB datapoints, grip strength in 10.6% (CIDP) and 8.8%/27.2% (MMNCB right/left hand) and MRC-SS in 43.5% (CIDP) and 20% (MMNCB). Multivariate LCMM identified subclinical trends toward improvement (32 patients) and deterioration (73 patients) in both cohorts. At baseline, CIDP 'deteriorators' were older than 'improvers' (66.2 versus 57 years, p=0.025). No other individual factors predicted categorisation. The best model for 'deteriorator' identification was contiguous sub-MCID decline in more than one outcome measure (CIDP: sensitivity 74%, specificity 59%; MMNCB: sensitivity 73%, specificity 88%).

DISCUSSION

Outcome measure interpretation determines therapeutic decision-making in Ig-dependent neuropathy patients, but intra-individual variation is common, often exceeding MCID. Here we show sub-MCID contiguous changes in more than one outcome measurement are a better predictor of long-term outcome. This article is protected by copyright. All rights reserved.

Treatment of myelin oligodendrocyte glycoprotein antibody associated disease with subcutaneous immune globulin

Myelin oligodendrocyte glycoprotein (MOG)-antibody associated disease (MOGAD) is a distinct demyelinating disease of the central nervous system that often exhibits a relapsing course. Immune globulin (Ig) therapy has been proposed as maintenance therapy to prevent relapses in MOGAD, but existing reports are limited to the use of intravenous Ig (IVIG). Subcutaneous Ig (SCIG) may exhibit several advantages over IVIG, including self-administration and less systemic adverse effects. Herein, we report six patients with MOGAD who were treated with subcutaneous Ig (SCIG) with good tolerability and without any relapses during follow-up. This supports the rationale for prospective randomized studies of SCIG in MOGAD.

Assessment of disability in idiopathic inflammatory myopathy: a call for linearity

Objectives

To evaluate the clinimetric properties of the Academic Medical Centre Disability Score (ALDS) in patients with idiopathic inflammatory myopathy (IIM).

Methods

We used prospectively collected data of IIM patients who completed a phase-2 study with first-line IVIG monotherapy. The ALDS is a patient-reported questionnaire which contains 25 items relevant for disability in myositis. ALDS and all core set measures (CSMs) for myositis [including HAQ-Disability Index (HAQ-DI)] were evaluated at baseline and 9 weeks follow-up. In addition, the 2016 ACR/EULAR myositis response criteria outcome called Total Improvement Score (TIS) was evaluated at 9 weeks. We examined floor/ceiling effects, reliability and construct validity of the ALDS. To examine known-group validity, ALDS change scores over time were compared with TIS and physician impression of clinical response.

Results

Nineteen patients with IIM [median age 59 years, 12 (63%) female] were enrolled. At baseline, ALDS showed a median score of 65.4 (IQR 58.2–73.5), good Cronbach’s alpha (α = 0.84) and a small ceiling effect (11%). Construct validity was confirmed by moderate to strong correlations between ALDS and HAQ-DI [r_s = −0.57 (baseline); −0.86 (follow-up)]. ALDS change score correlated with TIS (r_s = 0.70), discriminated between responders and non-responders (TIS ≥ 40; P = 0.001), between groups based on physician impression of clinical response (P = 0.03), and detected deterioration.

Conclusion

The ALDS showed promising clinimetric properties and detected relevant changes in disability in patients with myositis. These results warrant further investigations.

An approach to assessing immunoglobulin dependence in chronic inflammatory demyelinating inflammatory polyneuropathy

Regular immunoglobulin treatment maintains strength and prevents disability in chronic inflammatory demyelinating polyneuropathy (CIDP). Discrimination between active disease, with optimum symptom control on treatment, and disease in remission not requiring treatment is essential for therapeutic decision-making and clinical trial design. To compare treatment cessation versus gradual dose reduction in assessment of disease activity (immunoglobulin dependence) in a cohort of stable CIDP patients on maintenance immunoglobulin treatment. An approach to restabilization of immunoglobulin-dependent individuals is also described. Retrospective review of IVIg cessation or gradual reduction in 33 patients with stable CIDP on maintenance IVIg. Demographic, clinical and treatment data were collected; clinical monitoring data were recorded prospectively as part of routine clinical practice. A total of 21/33 patients (62.6%) were immunoglobulin dependent, (gradual dose reduction:11, cessation:10). Mean change in Inflammatory Rasch-built Overall Disability Scale (I-RODS) (-15, standard deviation [SD] 16) and Medical Research Council Sum Score (MRC-SS) (-4, SD: 4) was clinically and statistically meaningful (>75% exceeded minimum clinically important differences). Mean time to deterioration was 5.0 (SD: 4.6) months, shorter in cessation group (3.5 months) than gradual reduction group (8.8 months). All patients were restabilized to previous baseline (M: 2.3, SD: 4.3 months), half within 1 week of retreatment. A total of 12 patients (37.4%) remained stable without treatment for ≥2 years (remission). A total of 50% were identified rapidly by cessation and 50% by gradual dose reduction requiring mean 4.8 (SD: 2.8) years follow-up and costing £113 623 per person Ig spend. No predictors of disease activity were identified. A treatment cessation trial with close clinical monitoring is an efficient, cost-effective and safe approach to assessing disease activity in CIDP.

Novel Immunological and Therapeutic Insights in Guillain-Barré Syndrome and CIDP

Inflammatory neuropathies are a heterogeneous group of rare diseases of the peripheral nervous system that include acute and chronic diseases, such as Guillain-Barré syndrome (GBS) and chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). The etiology and pathophysiological mechanisms of inflammatory neuropathies are only partly known, but are considered autoimmune disorders in which an aberrant immune response, including cellular and humoral components, is directed towards components of the peripheral nerve causing demyelination and axonal damage. Therapy of these disorders includes broad-spectrum immunomodulatory and immunosuppressive treatments, such as intravenous immunoglobulin, corticosteroids, or plasma exchange. However, a significant proportion of patients do not respond to any of these therapies, and treatment selection is not optimized according to disease pathophysiology. Therefore, research on disease pathophysiology aiming to reveal clinically and functionally relevant disease mechanisms and the development of new treatment approaches are needed to optimize disease outcomes in CIDP and GBS. This topical review describes immunological progress that may help guide therapeutic strategies in the future in these two disorders.

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.

Update on Intravenous Immunoglobulin in Neurology: Modulating Neuro-autoimmunity, Evolving Factors on Efficacy and Dosing and Challenges on Stopping Chronic IVIg Therapy

In the last 25 years, intravenous immunoglobulin (IVIg) has had a major impact in the successful treatment of previously untreatable or poorly controlled autoimmune neurological disorders. Derived from thousands of healthy donors, IVIg contains IgG1 isotypes of idiotypic antibodies that have the potential to bind pathogenic autoantibodies or cross-react with various antigenic peptides, including proteins conserved among the "common cold"-pre-pandemic coronaviruses; as a result, after IVIg infusions, some of the patients' sera may transiently become positive for various neuronal antibodies, even for anti-SARS-CoV-2, necessitating caution in separating antibodies derived from the infused IVIg or acquired humoral immunity. IVIg exerts multiple effects on the immunoregulatory network by variably affecting autoantibodies, complement activation, FcRn saturation, FcγRIIb receptors, cytokines, and inflammatory mediators. Based on randomized controlled trials, IVIg is approved for the treatment of GBS, CIDP, MMN and dermatomyositis; has been effective in, myasthenia gravis exacerbations, and stiff-person syndrome; and exhibits convincing efficacy in autoimmune epilepsy, neuromyelitis, and autoimmune encephalitis. Recent evidence suggests that polymorphisms in the genes encoding FcRn and FcγRIIB may influence the catabolism of infused IgG or its anti-inflammatory effects, impacting on individualized dosing or efficacy. For chronic maintenance therapy, IVIg and subcutaneous IgG are effective in controlled studies only in CIDP and MMN preventing relapses and axonal loss up to 48 weeks; in practice, however, IVIg is continuously used for years in all the aforementioned neurological conditions, like is a "forever necessary therapy" for maintaining stability, generating challenges on when and how to stop it. Because about 35-40% of patients on chronic therapy do not exhibit objective neurological signs of worsening after stopping IVIg but express subjective symptoms of fatigue, pains, spasms, or a feeling of generalized weakness, a conditioning effect combined with fear that discontinuing chronic therapy may destabilize a multi-year stability status is likely. The dilemmas of continuing chronic therapy, the importance of adjusting dosing and scheduling or periodically stopping IVIg to objectively assess necessity, and concerns in accurately interpreting IVIg-dependency are discussed. Finally, the merit of subcutaneous IgG, the ineffectiveness of IVIg in IgG4-neurological autoimmunities, and genetic factors affecting IVIg dosing and efficacy are addressed.

Maintenance therapy with subcutaneous immunoglobulin in a patient with immune-mediated neuropathic postural tachycardia syndrome

Aims

We describe the disease course of a 35-year-old female with an autoimmune mediated neuropathic postural tachycardia syndrome (PoTS), who responded to immunoglobulin therapy and stabilized on maintenance therapy with subcutaneous immunoglobulin (SCIg).

Methods

We provide longitudinal data of clinical scores, tilt-table results and antibody titers.

Results

Initial treatment with intravenous immunoglobulin caused infusion-related side-effects whereas SCIg was well tolerated and improved clinical symptoms and quality of life. Clinical improvement correlated with the reduction of serum antibody titers 22 months after first infusion.

Conclusions

These findings suggest that autoimmune-mediated neuropathic PoTS can be treated sufficiently with IVIg whereas SCIg minimizes side-effects.

Pharmacometric analysis linking immunoglobulin exposure to clinical efficacy outcomes in chronic inflammatory demyelinating polyneuropathy

The two main objectives of this analysis were to (i) characterize the relationship between immunoglobulin (Ig) exposure and chronic inflammatory demyelinating polyneuropathy (CIDP) disease severity using data from 171 patients with CIDP who received either subcutaneous Ig (IgPro20; Hizentra^®) or placebo (PATH study), and to (ii) simulate and compare exposure coverage with various dosing approaches considering weekly dosing to be the reference dose. IgG pharmacokinetic (PK) parameters, including those from a previous population PK model, were used to predict individual IgG profile and exposure metrics. Treatment‐related changes in Inflammatory Neuropathy Cause and Treatment (INCAT) scores were best described by a maximum effect (E_max) model as a function of ΔIgG (total serum IgG at INCAT score assessment minus baseline IgG levels before intravenous Ig restabilization). Simulations indicate that flexible dosing from daily to biweekly (every other week) provide an exposure coverage equivalent to that of a weekly Ig dose.

European Academy of Neurology/Peripheral Nerve Society guideline on diagnosis and treatment of chronic inflammatory demyelinating polyradiculoneuropathy: Report of a joint Task Force-Second revision

OBJECTIVE

To revise the 2010 consensus guideline on chronic inflammatory demyelinating polyradiculoneuropathy (CIDP).

METHODS

Seventeen disease experts, a patient representative, and two Cochrane methodologists constructed 12 Population/Intervention/Comparison/Outcome (PICO) questions regarding diagnosis and treatment to guide the literature search. Data were extracted and summarized in GRADE summary of findings (for treatment PICOs) or evidence tables (for diagnostic PICOs).

RESULTS

Statements were prepared according to the GRADE Evidence-to-Decision frameworks. Typical CIDP and CIDP variants were distinguished. The previous term "atypical CIDP" was replaced by "CIDP variants" because these are well characterized entities (multifocal, focal, distal, motor, or sensory CIDP). The levels of diagnostic certainty were reduced from three (definite, probable, possible CIDP) to only two (CIDP and possible CIDP), because the diagnostic accuracy of criteria for probable and definite CIDP did not significantly differ. Good Practice Points were formulated for supportive criteria and investigations to be considered to diagnose CIDP. The principal treatment recommendations were: (a) intravenous immunoglobulin (IVIg) or corticosteroids are strongly recommended as initial treatment in typical CIDP and CIDP variants; (b) plasma exchange is strongly recommended if IVIg and corticosteroids are ineffective; (c) IVIg should be considered as first-line treatment in motor CIDP (Good Practice Point); (d) for maintenance treatment, IVIg, subcutaneous immunoglobulin or corticosteroids are recommended; (e) if the maintenance dose of any of these is high, consider either combination treatments or adding an immunosuppressant or immunomodulatory drug (Good Practice Point); and (f) if pain is present, consider drugs against neuropathic pain and multidisciplinary management (Good Practice Point).

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.

Autoimmune Neurogenic Dysphagia

Autoimmune neurogenic dysphagia refers to manifestation of dysphagia due to autoimmune diseases affecting muscle, neuromuscular junction, nerves, roots, brainstem, or cortex. Dysphagia is either part of the evolving clinical symptomatology of an underlying neurological autoimmunity or occurs as a sole manifestation, acutely or insidiously. This opinion article reviews the autoimmune neurological causes of dysphagia, highlights clinical clues and laboratory testing that facilitate early diagnosis, especially when dysphagia is the presenting symptom, and outlines the most effective immunotherapeutic approaches. Dysphagia is common in inflammatory myopathies, most prominently in inclusion body myositis, and is frequent in myasthenia gravis, occurring early in bulbar-onset disease or during the course of progressive, generalized disease. Acute-onset dysphagia is often seen in Guillain–Barre syndrome variants and slowly progressive dysphagia in paraneoplastic neuropathies highlighted by the presence of specific autoantibodies. The most common causes of CNS autoimmune dysphagia are demyelinating and inflammatory lesions in the brainstem, occurring in patients with multiple sclerosis and neuromyelitis optica spectrum disorders. Less common, but often overlooked, is dysphagia in stiff-person syndrome especially in conjunction with cerebellar ataxia and high anti-GAD autoantibodies, and in gastrointestinal dysmotility syndromes associated with autoantibodies against the ganglionic acetyl-choline receptor. In the setting of many neurological autoimmunities, acute-onset or progressive dysphagia is a potentially treatable condition, requiring increased awareness for prompt diagnosis and early immunotherapy initiation.

Outcome measures and biomarkers in chronic inflammatory demyelinating polyradiculoneuropathy: from research to clinical practice

Introduction: Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an immune-mediated syndrome characterized clinically by weakness and/or numbness that evolves over 2 months or more. The heterogeneity of clinical features necessitates an individualized approach to disease monitoring that takes lessons learned from clinical trials and applies them to clinical practice.Areas covered: This review discusses the importance of clinimetrics and biomarkers in CIDP diagnosis and disease monitoring. Highlighted are the challenges of defining responses to immunotherapy, the usefulness, and limitations of utilizing evidence-based clinical outcome measures during routine clinical care, and the evolving understanding of how diagnostic and disease activity biomarkers may reshape our treatment and disease monitoring paradigms.Expert opinion: Although disability and impairment outcome measures are commonly used in CIDP to indicate disease status, the nonspecific nature of these metrics limits the ability to attribute a change in any given metric to a change in CIDP. This interpretive challenge may be magnified by inconsistencies in the direction of change as well as a strong placebo effect. There is a need to improve our understanding of minimally important changes in existing outcome measures as a means to personalize treatment and to better assess disease activity status with biomarker discovery.

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.

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.

Efficacy of rituximab treatment in chronic inflammatory demyelinating polyradiculoneuropathy: a systematic review and meta-analysis

BACKGROUND

Current standard treatment in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) has been proved effective, but it is poorly effective in refractory patients and unclear for anti-IgG4 antibody-associated CIDP. Rituximab is a B cell-depleting monoclonal antibody. It has been applied as one of the management strategies in CIDP, but its efficacy is unknown.

OBJECTIVE

To perform a systematic review and a meta-analysis of the efficacy of rituximab treatment in CIDP patients.

METHODS

Through searches in MEDLINE, PubMed, EMBASE, BIOSOS, Web of Science, and Cochrane library on March 31st, 2021, 15 studies were identified. Patients' characteristics, treatment regime and outcome measure were extracted.

RESULTS

Ninety-six patients in 15 studies were included. The pooled estimate of responsiveness was 75% (95% CI 72-78%). The standard mean difference (SMD) of Inflammatory Neuropathy Cause and Treatment (INCAT) disability score improvement was 1.7 (95% CI 1.0-2.3, p value < 0.0001) and the Medical Research Council (MRC) score for muscle power is 1.3 (95% CI - 2.6 to - 0.1, p value 0.04). All of the anti-IgG4 antibody-positive patients showed excellent responses to rituximab treatment.

CONCLUSION

Rituximab was effective in the treatment in CIDP patients, especially in anti-IgG4 antibody-positive patients. Randomized clinical trials are needed to determine the effectiveness and safety of rituximab in CIDP patients.

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.

European Academy of Neurology/Peripheral Nerve Society guideline on diagnosis and treatment of chronic inflammatory demyelinating polyradiculoneuropathy: Report of a joint Task Force-Second revision

To revise the 2010 consensus guideline on chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). Seventeen disease experts, a patient representative, and two Cochrane methodologists constructed 12 Population/Intervention/Comparison/Outcome (PICO) questions regarding diagnosis and treatment to guide the literature search. Data were extracted and summarized in GRADE summary of findings (for treatment PICOs) or evidence tables (for diagnostic PICOs). Statements were prepared according to the GRADE Evidence-to-Decision frameworks. Typical CIDP and CIDP variants were distinguished. The previous term "atypical CIDP" was replaced by "CIDP variants" because these are well characterized entities (multifocal, focal, distal, motor, or sensory CIDP). The levels of diagnostic certainty were reduced from three (definite, probable, possible CIDP) to only two (CIDP and possible CIDP), because the diagnostic accuracy of criteria for probable and definite CIDP did not significantly differ. Good Practice Points were formulated for supportive criteria and investigations to be considered to diagnose CIDP. The principal treatment recommendations were: (a) intravenous immunoglobulin (IVIg) or corticosteroids are strongly recommended as initial treatment in typical CIDP and CIDP variants; (b) plasma exchange is strongly recommended if IVIg and corticosteroids are ineffective; (c) IVIg should be considered as first-line treatment in motor CIDP (Good Practice Point); (d) for maintenance treatment, IVIg, subcutaneous immunoglobulin or corticosteroids are recommended; (e) if the maintenance dose of any of these is high, consider either combination treatments or adding an immunosuppressant or immunomodulatory drug (Good Practice Point); and (f) if pain is present, consider drugs against neuropathic pain and multidisciplinary management (Good Practice Point).

Recovery of foot drop in chronic inflammatory demyelinating polyneuropathy (CIDP)

INTRODUCTION/AIMS

Foot drop is common in chronic inflammatory demyelinating polyneuropathy (CIDP), but its prognosis is uncertain.

METHODS

CIDP patients with less than anti-gravity strength (<3/5 power) of ankle dorsiflexion (ADF) on Medical Research Council manual muscle testing on presentation at our center were identified by retrospective review. After initiation of standard treatment, ADF power was serially tabulated, and predictors of recovery were determined.

RESULTS

Of the 27 identified patients, ADF power at presentation was <3/5 in 48/54 legs. At 1 y after treatment, ADF power improved to >/= 3/5 in 17/27 patients in one (N = 6) or both (N = 11) legs. On multi-variate analysis, predictors of recovery of ADF power were tibialis anterior compound muscle action potential amplitude at presentation, shorter disease duration, and female gender.

DISCUSSION

Foot drop improves to anti-gravity power in most treated CIDP patients depending in part on the severity of fibular motor axon loss at onset of treatment.

The influence of the COVID-19 pandemic on patients with chronic inflammatory demyelinating polyradiculoneuropathy

OBJECTIVES

At a time of global health crisis, fear, anxiety, and stress levels increase. The effects of protracted social isolation, and media related misinformation's about the coronavirus disease 2019 (COVID-19) resulting in increased fear/stress related to the insufficiently known illness. The aim was to assess the influence of the COVID-19 health crisis on patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP).

METHODS

A cross-sectional study on 29 adult CIDP patients was performed. The Medical Research Council scale was used to evaluate muscle strength. The degree of functional disability was measured using the Inflammatory Neuropathy Cause and Treatment disability scale. The overall quality of life (QoL) was self-estimated on a 0-100 numeric rating scale. We also used a specifically designed 22-question-survey about COVID-19.

RESULTS

Regarding the COVID-19 pandemic, 62% of CIDP patients were concerned. The daily activities of 55% of patients were negatively influenced by the pandemic. During the COVID-19 outbreak, 21% of patients reported their CIDP got worse. In 39% of CIDP patients, the influence of the pandemic on CIDP therapy was reported (reducing the dose or time interval or even discontinuation). The mean value of the self-estimated QoL was 64 ± 19. Independent predictors of worse QoL were age of patients (beta = -0.35, p < 0.05) and fear of the COVID-19 (beta = -0.34, p < 0.05).

CONCLUSION

The COVID-19 pandemic has a significant impact on CIDP patients. Besides the direct influence of the virus and fear of the virus, restrictive measures can indirectly harm the patients with CIDP.

Patient Preferences for Subcutaneous versus Intravenous Administration of Treatment for Chronic Immune System Disorders: A Systematic Review

BACKGROUND

For many chronic immune system disorders, the available treatments provide several options for route of administration. The objective of this systematic literature review is to inform discussions about therapy choices for individual patients by summarizing the available evidence regarding the preferences of patients with chronic immune system disorders for intravenous (IV) or subcutaneous (SC) administration.

METHODS

Searches of the MEDLINE, Embase and Cochrane Library databases were conducted using terms designed to capture studies reporting patient preferences between IV and SC therapy published in English. Relevant studies were limited to those in which mode of administration, including treatment frequency and setting, was the main difference between comparators.

RESULTS

In total, 49 studies were included in the review. Among 18 studies that compared IV and SC immunoglobulin therapy, 16 found patients to prefer the SC administration route. The results of the 31 studies comparing IV infusion and SC injection of non-immunoglobulin therapies were mixed, with patients favoring SC administration in 20, IV infusion in seven, and having no overall preference in four. Patient experience had a strong effect on preferences, with treatment-experienced patients preferring their current administration route in most studies. Patients preferring SC administration tended also to prefer treatment at home, mainly due to the convenience and comfort of home treatment and the avoidance of having to attend hospital. By contrast, patients preferring IV infusion tended to cite the lower treatment frequency and a dislike of self-injecting, and preferred hospital treatment, mainly due to the presence of healthcare professionals and resulting feelings of safety.

CONCLUSION

In general patients with chronic immune system disorders tend to be more likely to choose SC administration than IV infusion, but preferences may vary according among individuals. These findings may assist discussions around appropriate treatment choices for each patient.

Switch from intravenous to subcutaneous immunoglobulin IgPro20 in CIDP patients: a prospective observational study under real-world conditions

Background:

IgPro20 is the first approved subcutaneous immunoglobulin (SCIg) preparation for the treatment of patients with chronic inflammatory demyelinating polyneuropathy (CIDP). Two different doses of the SCIg preparation were investigated in the pivotal PATH study. Real-world data, and particularly the efficacy of an equivalent dose switch from intravenous immunoglobulin (IVIg) to SCIg, are still not available.

Methods:

In this prospective observational study, 41 patients with CIDP treated with intravenous immunoglobulin (IVIg) were changed to an equivalent (1:1) dose of IgPro20 1 week after last IVIg treatment. Patients were examined at the time of switch from IVIg to SCIg, after 3 and after 6 months and efficacy, treatment preferences and systemic and local reactions were assessed.

Results:

Various clinical outcome parameters demonstrated overall stability regarding disability, general activity and social participation, grip and muscle strength, as well as gait impairment. Treatment satisfaction remained unchanged between IVIg and SCIg therapy. However, 88% of patients favoured treatment with subcutaneous IgPro20 over IVIg 6 months after switch to IgPro20.

Conclusion:

Results demonstrate that the switch of IVIg to an equivalent dose of SCIg represents an effective and preferred treatment option for CIDP patients.

Prognostic value of neurofilament light chain in chronic inflammatory demyelinating polyneuropathy

Chronic inflammatory demyelinating polyneuropathy is a neuroinflammatory disorder with considerable variation in clinical phenotype, disease progression and therapy response among patients. Recently, paranodal antibodies associated with poor response to intravenous immunoglobulin therapy and more aggressive disease course have been described in small subsets of patients, but reliable serum-based prognostic biomarkers are not yet available for the general population. In current retrospective longitudinal study, we utilized logistic regression models to investigate the associations of serum neurofilament light chain levels with 1-year disease progression and therapy response during follow-up in chronic inflammatory demyelinating polyneuropathy. One-year disease progression was defined as a decrease of four or more points (the minimal clinically important difference) on an 80-point Medical Research Council sum-score scale 1 year after sampling. Patients who, compared to treatment received at time of sampling, required therapy switch during follow-up due to insufficient effect were classified as non-responders. Serum neurofilament light chain was measured by electrochemiluminescence assay in clinical residual serum samples of 76 patients diagnosed with probable (13 patients) or definite (63 patients) chronic inflammatory demyelinating polyneuropathy according to European Federation of Neurological Societies/Peripheral Nerve Society diagnostic criteria. Eleven (15%) patients were female, and the mean (standard deviation) cohort age was 61.5 (11.7) years. In both univariate and multivariable (including demographics) models, elevated serum neurofilament light chain harboured increased odds for 1-year disease progression (respectively odds ratio, 1.049; 95% confidence interval, 1.022-1.084 and odds ratio, 1.097; 95% confidence interval, 1.045-1.169; both P = 0.001). Patients with levels above the median cohort neurofilament light chain level (28.3 pg/ml) had largely increased odds of 1-year disease progression (univariate: odds ratio, 5.597; 95% confidence interval, 1.590-26.457; P = 0.01; multivariable: odds ratio, 6.572; 95% confidence interval, 1.495-39.702; P = 0.02) and of insufficient treatment response (univariate: odds ratio, 4.800; 95% confidence interval, 1.622-16.442; P = 0.007; multivariable: odds ratio, 6.441; 95% confidence interval, 1.749-29.357; P = 0.009). In a combined approach analysis, patients with levels above median cohort serum neurofilament light chain level reported strongly increased odds of demonstrating 1-year disease progression and/or therapy non-response during follow-up (univariate: odds ratio, 6.337; 95% confidence interval, 2.276-19.469; P < 0.001; multivariable: odds ratio, 10.138; 95% confidence interval, 2.801-46.404; P = 0.001). These results show that in various logistic regression models, serum neurofilament light chain was associated with both 1-year disease progression and therapy response during follow-up in chronic inflammatory demyelinating polyneuropathy. Hence, our findings warrant further prospective research regarding the value of neurofilament light chain as potential prognostic biomarker in chronic inflammatory demyelinating polyneuropathy.

Synthesis, characterization and advanced sustainable applications of titanium dioxide nanoparticles: A review

Nanotechnology is capturing great interest worldwide due to their stirring applications in various fields. Among nanoparticles (NPs), titanium dioxide (TiO2) NPs have been widely used in daily life and can be synthesized through various physical, chemical, and green methods. Green synthesis is a non-toxic, cost-effective, and eco-friendly route for the synthesis of NPs. Plenty of work has been reported on the green, chemical, physical and biological synthesis of TiO2 NPs and these NPs can be characterized through high tech. instruments. In the present review, dense data have been presented on the comparative synthesis of TiO2 NPs with different characteristics and their wide range of applications. Among the TiO2 NPs synthesis techniques, the green methods have been proven to be efficient than chemical synthesis methods because of the less use of precursors, time-effectiveness, and energy-efficiency during the green synthesis procedures. Moreover, this review describes the types of plants (shrubs, herbs and trees), microorganisms (bacteria, fungi and algae), biological derivatives (proteins, peptides, and starches) employed for the synthesis of TiO2 NPs. The TiO2 NPs can be effectively used for the treatment of polluted water and positively affected the plant physiology especially under abiotic stresses but the response varied with types, size, shapes, doses, duration of exposure, metal species along with other factors. This review also highlights the regulating features and future standpoints for the measurable enrichment in TiO2 NPs product and perspectives of TiO2 NPs reliable application.

Monitoring Clinical Course and Treatment Response in Chronic Inflammatory Demyelinating Polyneuropathy During Routine Care: A Review of Clinical and Laboratory Assessment Measures

Importance

Identifying clinical change in many neurologic diseases, including chronic inflammatory demyelinating polyneuropathy (CIDP), can be challenging. At the same time, how change is defined heavily influences a patient's diagnostic and treatment pathway. It can be especially problematic when equivocal subjective observations are interpreted as clinically meaningful and then used to make diagnostic and treatment decisions. Change in clinical trials is strictly defined by a preselected metric, but there is a perception that formal outcomes collection during routine clinical care is neither feasible nor necessary. Given the importance placed on how change is interpreted, there is a need to select assessments that can be applied to routine care that are representative of the neurologic disease state.

Observations

For an outcome measure to be useful during clinical trials, it must have good reliability, validity, be responsive to change, and have clinical meaning. To be useful during routine clinical care, the assessment must additionally be easy to collect without the need for extensive training or equipment and should provide an immediately available result that can be rapidly quantified and interpreted. Chronic inflammatory demyelinating polyneuropathy is clinically heterogeneous and so is best evaluated with a diverse group of assessment tools. Assessing strength impairment, disability, and quality of life is ideally suited for everyday practice when caring for patients with CIDP. While electrophysiologic studies, imaging, cerebrospinal fluid, and nodal/paranodal antibodies can provide diagnostic data, they are less practical and helpful longitudinal assessment tools.

Conclusions and Relevance

Sound clinimetric outcome measures in CIDP are widely available and have the potential to help clinicians objectify treatment response and disease progression. Such data are critically important when justifying the need for ongoing or periodic immunotherapy, documenting relapse or deterioration, or providing reassurance of disease improvement, stability, or remission.

Practical Aspects of Transitioning from Intravenous to Subcutaneous Immunoglobulin Therapy in Neuromuscular Disorders

Recent evidence shows that subcutaneous immunoglobulin (SCIG) is as efficacious as intravenous immunoglobulin (IVIG) and has a better safety profile and acceptance rate among patients with neuromuscular disorders who require maintenance IVIG treatment. Awareness of the practical aspects of patient selection, enrollment, dose calculation, administration, and follow-up would help physicians coordinate a smooth and seamless transition from IVIG to SCIG. SCIG is ideally offered to patients having intolerable side effects during IVIG or wearing-off effect and in those keen for treatment autonomy. The weekly dose of SCIG is calculated by multiplying the maintenance dose of IVIG by the dose adjustment factor and dividing by the interval between IVIG in weeks and is initiated 1 week after the last dose of IVIG. The physician places the order for the SCIG and the clinic nurse or the physician refers the patient to the home care nursing program for further education and training. The necessary supplies are dispatched to the patient who would also collect the SCIG from the transfusion center of the nearest hospital. The patient is educated on assembling and administering the infusion, and home visits are continued until the patient or caregiver is confident. Regular follow-up with the patient is maintained to assess treatment response and side effects if any. With a smooth transition, most patients have excellent tolerance to SCIG and in our experience seldom request switching back to IVIG. Transitioning patients from IVIG to SCIG offers several advantages and thus, in general, is preferable for multiple stakeholders.

Use of subcutaneous immunoglobulin in stiff person syndrome: Case series

INTRODUCTION

Intravenous immunoglobulin (IVIG) has been shown to be effective for the treatment of stiff person syndrome (SPS). However, some patients might not tolerate it. We report the tolerability profile of subcutaneous immunoglobulin (SCIg) in patients with SPS who did not tolerate IVIG. To our knowledge, the use of SCIg in SPS has not been reported before in a case series.

PATIENT CONCERNS

The five patients included in this case series presented with various combinations of symptoms of spasms, axial and limb stiffness, and exaggerated responses to outside stimuli. These symptoms often lead to gait and functional impairment.

DIAGNOSIS

Patients were diagnosed with classic SPS as they met the clinical criteria, which require the presence of spasms, axial rigidity, and hyperexcitability.

INTERVENTIONS

Subcutaneous immunoglobulin infusion.

OUTCOMES

Five patients were identified that were treated with SCIg. Three tested positive for serum anti-glutamic acid decarboxylase 65 antibodies prior to any treatment. The mean age at SCIg initiation was 33 years (range: 22-47). The mean duration of SPS prior to SCIg initiation was 5.9 years (range: 2.5-7). All patients used IVIG for at least two months (up to 18 months) but switched to SCIg due to IVIG side effects. Duration of SCIg use ranged from 4 months to 6 years (mean, 19.2 months). Upon switching to SCIg, the SPS symptoms remained stable. SCIg was well-tolerated in most as only one patient discontinued SCIg due to side effects.

CONCLUSION

This case series highlights that SCIg could be a treatment option for patients with SPS, especially when IVIG is not feasible. Injection site reactions might be a limiting factor in some patients treated with SCIg. Prospective controlled studies are needed to confirm SCIg treatment durability and efficacy.

Immunotherapy for Peripheral Nerve Disorders

Inflammatory peripheral neuropathies can be disabling for any patient. Selecting the most appropriate agent for treatment, especially in the elderly, is no simple task. Several factors should be considered. Herein, we discuss immunotherapeutic options for peripheral nerve diseases and the important considerations required for choosing one in the geriatric population.

Chronic Immune-Mediated Polyneuropathies

This article discusses the chronic immune-mediated polyneuropathies, a broad category of acquired polyneuropathies that encompasses chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), the most common immune-mediated neuropathy, the CIDP variants, and the vasculitic neuropathies. Polyneuropathies associated with rheumatological diseases and systemic inflammatory diseases, such as sarcoidosis, will also be briefly covered. These patients' history, examination, serum studies, and electrodiagnostic studies, as well as histopathological findings in the case of vasculitis, confirm the diagnosis and differentiate them from the more common length-dependent polyneuropathies. Prompt identification and initiation of treatment is imperative for these chronic immune-mediated polyneuropathies to prevent disability and even death.

The Cost Effectiveness of Immunoglobulin vs. Hematopoietic Stem Cell Transplantation for CIDP

Background: Intravenous immunoglobulin (IVIG) is effective as standard first line therapy for chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), but some patients remain dependent on its long-term use. Recently, we have reported that autologous non-myeloablative hematopoietic stem cell transplantation (HSCT) is an effective second line therapy for CIDP. Objectives: To compare the cost of chronic IVIG vs. autologous HSCT (a one-time therapy), we collected data on patients with CIDP undergoing HSCT between 2017 and 2019. This was compared with published literature on the costs and efficacy defined by the Inflammatory Neuropathy Cause And Treatment (INCAT) disability score, Medical Research Council (MRC) sum score, hand grip strength, and SF-36 quality of life (QOL) for CIDP. Methods: Between 2017 and 2019, nineteen patients with chronic CIDP (mean disease treatment duration prior to HSCT of 6 years) underwent autologous HSCT with mean cost of $108,577 per patient (range $56,327-277,119, standard deviation $53,092). After HSCT, 80% of patients remain IVIG and immune treatment free for up to 5 years. In comparison, published cost of IVIG treatment in the USA for an average CIDP patient exceeds $136,000 per year. Despite remaining treatment free, HSCT demonstrated greater improvement in efficacy compared to immunoglobulins. Recommendations: Given the long-term treatment-free remission and better outcome measurements, autologous HSCT is more cost effective than long-term IVIG treatment in patients with chronic CIDP. However, costs will depend on patient selection, the HSCT regimen, and regional variations. Further analysis of the health economics, i.e., cost/outcome ratio, of HSCT as therapy for chronically IVIG dependent CIDP is warranted.

Individualizing Therapy in CIDP: A Mini-Review Comparing the Pharmacokinetics of Ig With SCIg and IVIg

Immunoglobulin (Ig) therapy is a first-line treatment for CIDP, which can be administered intravenously (IVIg) or subcutaneously (SCIg) and is often required long term. The differences between these modes of administration and how they can affect dosing strategies and treatment optimization need to be understood. In general, the efficacy of IVIg and SCIg appear comparable in CIDP, but SCIg may offer some safety and quality of life advantages to some patients. The differences in pharmacokinetic (PK) profile and infusion regimens account for many of the differences between IVIg and SCIg. IVIg is administered as a large bolus every 3–4 weeks resulting in cyclic fluctuations in Ig concentration that have been linked to systemic adverse events (AEs) (potentially caused by high Ig levels) and end of dose “wear-off” effects (potentially caused by low Ig concentration). SCIg is administered as a smaller weekly, or twice weekly, volume resulting in near steady-state Ig levels that have been linked to continuously maintained function and reduced systemic AEs, but an increase in local reactions at the infusion site. The reduced frequency of systemic AEs observed with SCIg is likely related to the avoidance of high Ig concentrations. Some small studies in immune-mediated neuropathies have focused on serum Ig data to evaluate its potential use as a biomarker to aid clinical decision-making. Analyzing dose data may help understand how establishing and monitoring patients' Ig concentration could aid dose optimization and the transition from IVIg to SCIg therapy.