Inflammatory Neuropathy Cause And Treatment Research Articles

Prospective Study of Acalabrutinib with Rituximab in Patients with Symptomatic Anti-MAG Mediated IgM Peripheral Neuropathy

Background: Peripheral neuropathy (PN) occurs in 20-25% of patients with an IgM paraprotein and up to 50% of these patients have an anti-myelin associated glycoprotein (MAG) antibody which is frequently associated with sensory ataxia and distal limb weakness negatively affecting function and quality of life. While rituximab is active, its activity is limited as a monotherapy and often associated with an IgM flare that can potentiate PN. BTK-inhibitors can block rituximab-associated IgM flare and are proven to markedly reduce serum IgM in Waldenström's Macroglobulinemia (WM). We therefore initiated this trial to evaluate a novel treatment for anti-MAG PN. Methods: We initiateda prospective, single-arm phase II study of acalabrutinib and rituximab (NCT05065554). Patients with an anti-MAG antibody with an IgM monoclonal gammopathy or WM; and a predominantly sensory demyelinating PN with a modified Rankin score of ≥1 with progressive symptoms or a score of ≥2 are eligible. Treatment consists of continuous oral acalabrutinib (100 mg twice daily) with rituximab weekly in cycles 1 and 4. Each cycle is 28 days. The primary endpoint is to evaluate the hematologic response rate. The key secondary endpoint is to evaluate the proportion of patients that achieve improvement or stability in PN based on the Inflammatory Rasch-built Overall Disability Scale (I-RODS) patient-reported disability scale. Additional secondary neurologic endpoints include the Inflammatory Neuropathy Cause and Treatment (INCAT) disability score, MRC distal sum score, INCAT sensory sum score, and a neuropathy-specific quality of life scale (IN-QOL). We hypothesize that 75% of participants (H1) will have a hematologic response versus a null (H0) of 50% or lower. With 33 evaluable patients, there will be 82% power to detect a significant difference with an alpha (2-sided) of 0.04. Results: Eight patients, including 4 females, have enrolled as of July 1, 2023. The median age is 70 years (range 65-76), and median ECOG is 1. Median I-RODS score at baseline was 41 (range 23-48; 48 = no disability). All patients have an IgM kappa paraprotein with median baseline serum IgM of 975 mg/dL (range 226-2137), kappa free light chain of 28 mg/L (range 16-47), and M-spike of 0.6 g/dL (range 0.17-1.1). Anti-MAG antibody titer range is 1:70,000 to 1:819,200 IU/L. Bone marrow biopsy showed no disease in 4 patients, a clonal plasma cell population in 1 patient, and lymphoplasmacytic infiltrate in 3 patients. No adenopathy or splenomegaly were detected on baseline CT scans. Six patients (75%) are MYD88 mutated and none CXCR4 mutated. Five patients had prior rituximab therapy and two received prior IVIG. With a median time on treatment of 175 days (range 28-510), the overall response rate among 7 evaluable patients using IWWM-11 criteria was 86%. Categorical responses include 2 very good partial responses (≥90% decrease in IgM, or normalization of IgM with persistent IgM monoclonal protein); 1 partial response (≥50% but <90% decrease in IgM); 3 minor responses (≥25% but <50% decrease in IgM) and 1 stable disease. Four of 7 patients (57%) had improvement in the I-RODS score. Median improvement was 0.5 points (range -4 to 11). One patient was removed from the trial after 28 days due to grade 3 elevation in ALT. Two other reversible grade 3 adverse events occurred including rituximab related infusion reaction and syncope unrelated to treatment. Conclusions: The combination of acalabrutinib and rituximab has demonstrated activity in this first prospective study that is evaluating BTK-inhibition with CD20 directed therapy in patients with IgM related anti-MAG PN. Hematologic responses occurred in 86% of patients and 57% had an improvement in the I-RODS score. Treatment is well tolerated. Additional data from more detailed neurologic assessments are forthcoming. The trial continues to enroll patients. Our findings provide a framework to develop novel, more effective treatment options for anti-MAG PN.

High-dose pharmaceutical-grade biotin in patients with demyelinating neuropathies: a phase 2b open label, uncontrolled, pilot study

BackgroundWe proposed to investigate high-dose pharmaceutical-grade biotin in a population of demyelinating neuropathies of different aetiologies, as a proof-of-concept.MethodsPhase IIb open label, uncontrolled, single center, pilot study in 15 patients (three groups of five patients) with chronic demyelinating peripheral neuropathy, i.e. chronic inflammatory demyelinating polyradiculoneuropathy, anti-myelin-associated glycoprotein neuropathy and Charcot-Marie-Tooth 1a or 1b. The investigational product was high-dose pharmaceutical-grade biotin (100 mg taken orally three times a day over a maximum of 52 weeks.The primary endpoint was a 10% relative improvement in 2 of the following 4 electrophysiological variables: motor nerve conduction velocity, distal motor latency, F wave latency, duration of the compound muscle action potential. The secondary endpoints included Overall Neuropathy Limitations Scale (ONLS) score, Medical Research Council (MRC) sum score, Inflammatory Neuropathy Cause and Treatment (INCAT) sensory sum score, 10-m walk test, 6-min walk test, posturography parameters, and nerve excitability variables.ResultsThe primary endpoint was reached in one patient. In the full population analysis, some secondary endpoints parameters improved: MRC score, INCAT sensory sum score, 6-min walk distance, strength-duration time constant, and rheobase. There was a positive correlation between the improvement in the 6-min walk distance and the strength-duration time constant. Regarding the safety results, 42 adverse events occurred, of which three were of severe intensity but none was considered as related to the investigational product.ConclusionsEven if the primary endpoint was not met, administration of high-dose pharmaceutical-grade biotin led to an improvement in various sensory and motor parameters, gait abilities, and nerve excitability parameters. The tolerance of the treatment was satisfactory.Trial registrationClinicalTrials.gov Identifier: NCT02967679; date 2016/12/05.

In persons with CIDP, auto-HSCT can be conducted fully on an outpatient basis and induces significant clinical responses: A prospective study in a single center

BackgroundChronic inflammatory demyelinating polyneuropathy (CIDP) is one of the world's most common treatable neuropathy which usually responds to immunosuppressive treatment. Autologous hematopoietic stem cell transplantation (aHSCT) is an intense way of inducing immunosuppression. ObjectiveWe analyze the evolution of CIDP patients treated with aHSCT in our center. MethodsBetween 2018 and 2023, persons with CIDP were prospectively autografted employing the “Mexican method” to conduct grafts on an outpatient basis, employing cyclophosphamide 200 mg/Kg and rituximab 1000 mg. The protocol is registered in ClinicalTrials.gov identifier NCT02674217. ResultsIn our center 21 autologous transplant cases were completed in 2018–2023. Seven patients provided data to assess the efficacy of the procedure. Positive responses (stabilization and/or improvement) were observed in all seven patients: Five reported improvements in the Inflammatory Neuropathy Cause and Treatment (INCAT) score and one reported stabilization. In the Inflammatory Rasch-Built Overall Disability Scale (I-RODS) score. Median INCAT score was 5 (range 1–9), whereas median I-RODS score was 24 (range 11–29). Five patients (71%) reported improvement in the INCAT score, one reported stabilization and one informed worsening; concerning the I-RODS score 5 (71%) informed improvement, whereas two reported stabilization. ConclusionaHSCT conducted fully in an outpatient basis, employing the conditioning regimen of the “Mexican method” appears to be a feasible therapeutic option for persons with CIDP. Additional studies are needed to confirm these observations.

Anti-myelin-associated glycoprotein neuropathy: Where do we stand?

Myelin-associated glycoprotein (MAG) is a transmembrane glycoprotein concentrated in periaxonal Schwann cell and oligodendroglial membranes of myelin sheaths that serves as an antigen for immunoglobulin M (IgM) monoclonal antibodies. Individuals who harbor anti-MAG antibodies classically develop a progressive autoimmune peripheral neuropathy characterized clinically by ataxia, distal sensory loss, and gait instability, and electrophysiologically by distally accentuated conduction velocity slowing. Although off-label immunotherapy is common, there are currently no proven effective disease-modifying therapeutics, and most patients experience slow accumulation of disability over years and decades. The typically slowly progressive nature of this neuropathy presents unique challenges when trying to find effective anti-MAG therapeutic agents. Drug development has also been hampered by the lack of validated outcome measures that can detect clinically meaningful changes in a reasonable amount of time as well as by the lack of disease activity biomarkers. In this invited review, we provide an update on the state of clinicometric outcome measures and disease activity biomarkers in anti-MAG neuropathy. We highlight the insensitivity of widely used existing clinicometric outcome measures such as the Inflammatory Neuropathy Cause and Treatment (INCAT) disability score as well as the INCAT sensory subscore in anti-MAG neuropathy, referencing the two previous negative randomized controlled clinical trials evaluating rituximab. We then discuss newly emerging candidate therapeutic agents, including tyrosine kinase inhibitors and enhanced B-cell-depleting agents, among others. We conclude with a practical approach to the evaluation and management of anti-MAG neuropathy patients.

Fatigue, depression, and product tolerability during long-term treatment with intravenous immunoglobulin (Gamunex® 10%) in patients with chronic inflammatory demyelinating polyneuropathy

Introduction/AimsChronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is characterized by progressive weakness and sensory loss, often affecting patient’s ability to walk and perform activities of daily living independently. Furthermore, patients often report fatigue and depression which can affect their quality of life. These symptoms were assessed in CIDP patients receiving long-term intravenous immunoglobulin (IVIG) treatment.MethodsGAMEDIS was a multi-center, prospective, non-interventional study in adult CIDP patients treated with IVIG (10%) and followed for two years. Inflammatory Neuropathy Cause and Treatment (INCAT) disability score, Hughes Disability Scale (HDS), Fatigue Severity Scale (FSS), Beck Depression Inventory II (BDI), Short Form-36 health survey (SF-36) and Work Productivity and Activity Impairment Score Attributable to General Health (WPAI-GH) were assessed at baseline and quarterly. Dosing and treatment intervals, changes in outcome parameters, and adverse events (AEs) were analyzed.Results148 evaluable patients were followed for a mean of 83.3 weeks. The mean maintenance IVIG dose was 0.9 g/kg/cycle (mean cycle interval 38 days). Disability and fatigue remained stable throughout the study. Mean INCAT score: 2.4 ± 1.8 at baseline and 2.5 ± 1.9 at study end. HDS: 74.3% healthy/minor symptoms at baseline and 71.6% at study end. Mean FSS: 4.2 ± 1.6 at baseline and 4.1 ± 1.7 at study end. All patients reported minimal/no depression at baseline and throughout. SF-36 and WPAI-GH scores remained stable. Fifteen patients (9.5%) experienced potentially treatment-related AEs. There were no AEs in 99.3% of infusions.DiscussionLong-term treatment of CIDP patients with IVIG 10% in real-world conditions maintained clinical stability on fatigue and depression over 96 weeks. This treatment was well-tolerated and safe.

Mutational Profile in 75 Patients With Anti-Myelin-Associated Glycoprotein Neuropathy: Clinical and Hematologic Therapy Response and Hints on New Therapeutic Targets.

Neuropathy with antibodies to myelin-associated glycoprotein (MAG) is the most common paraproteinemic IgM neuropathy. Recently, the mutational profile of the MYD88 and CXCR4 genes has been included in the diagnostic workup of IgM monoclonal gammopathies. The objective of our study was to assess the prevalence of MYD88 L265P and CXCR4 S338X gene variants in patients with anti-MAG antibody neuropathy. Secondary aims were to evaluate possible correlations between the mutational profile and neuropathy severity, antibody titers, and treatment response. Seventy-five patients (47 men, mean age at molecular analysis 70.8 ± 10.2 years; mean disease duration 5.1 ± 4.9 years) with anti-MAG antibody neuropathy were recruited. Among them, 38 (50.7%) had IgM monoclonal gammopathy of undetermined significance, 29 (38.7%) Waldenstrom macroglobulinemia (WM), and 8 (10.6%) chronic lymphocytic leukemia/marginal zone lymphoma/hairy cell leukemia variant. Molecular analysis was performed on DNA from the bone marrow mononuclear cells in 55 of 75 patients and from peripheral mononuclear cells in 18 of 75 patients. Forty-five patients were treated with rituximab, 6 with ibrutinib, 2 with obinutuzumab-chlorambucil, and 3 with venetoclax-based therapy. All the patients were assessed with the Inflammatory Neuropathy Cause and Treatment (INCAT) Disability Scale, INCAT Sensory Sum Score, and MRC Sum Score at baseline and follow-up. We considered as responders, patients who improved by at least 1 point in 2 clinical scales. Fifty patients (66.7%) carried the MYD88L265P variant, with a higher frequency in WM and naive patients (77.2% vs 33.3%, p = 0.0012). No patients harbored the CXCR4S338X variant. There were no significant differences in hematologic data (IgM levels, M protein, and anti-MAG antibody titers), neuropathy severity, or response to rituximab in MYD88-altered and MYD88 wild-type patients. Nine of 11 (81.8%) patients treated with novel targeted drug, according to the MYD88 status, responded to treatments. MYD88L265P variant has a high prevalence (66.7%) in anti-MAG antibody neuropathy representing a potential effective mutational target for Bruton tyrosine kinase inhibitors. MYD88L265P variant, however, does not seem to be a prognostic factor of neuropathy severity or response to rituximab. In patients not responding or becoming refractory to rituximab, a tailored therapy with new effective target therapies should be considered.

Parameters Associated with the Required Drug Dose of Intravenous Immunoglobulin in Stable Chronic Inflammatory Demyelinating Polyradiculoneuropathy

Intravenous immunoglobulin (IVIg) is efficient and one of very few treatment options for patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). However, finding the optimal dose of IVIg for individual CIDP patients remains challenging. The dose of IVIg needs to be adjusted individually. Considering the high healthcare costs of IVIg therapy, the overtreatment of some patients seen in placebo studies and the shortage of IVIg we recently experienced, as well as identifying factors associated with the required dose of IVIg in maintenance treatment, is extremely important. Thus, in this retrospective study, we analyze characteristics of patients with stable CIDP, which are associated with the required drug dose. 32 patients with stable CIDP treated with IVIg between July 2021 and July 2022 were identified from our database and included in this retrospective study. Patients' characteristics were registered, and parameters were identified that were associated with the IVIg dose. Age, cerebrospinal fluid protein elevation, disease duration, delay between symptom onset/diagnosis, Inflammatory Neuropathy Cause and Treatment (INCAT) score, and Medical Research Council Sum Score (MRC SS) were significantly associated with the required drug dose. In addition, an association of age, sex, elevated CSF protein, time interval between symptom onset and diagnosis, and the MRC SS with the required IVIg dose could be demonstrated in the multivariable regression analysis. Our model, which is based on routine parameters that are simple to address in the clinical practice, can be useful in adjusting the IVIg dose in patients with stable CIDP.

Validation of elevated levels of interleukin-8 in the cerebrospinal fluid, and discovery of new biomarkers in patients with GBS and CIDP using a proximity extension assay.

Biomarkers for diagnosis of inflammatory neuropathies, assessment of prognosis, and treatment response are lacking. CSF and EDTA plasma from patients with Guillain-Barré syndrome (GBS), chronic inflammatory demyelinating polyneuropathy (CIDP), healthy controls (HC) and disease controls were analyzed with Olink multiplex proximity extension assay (PEA) from two independent cohorts. Levels of interleukin-8 (IL8) were further analyzed with ELISA in patients with GBS, CIDP, paraproteinemia-related demyelinating polyneuropathy (PDN), multifocal motor neuropathy (MMN), HC and disease controls. ROC analysis was performed. Outcome was measured with the GBS-disability score (GBS-ds) or Inflammatory Neuropathy Cause and Treatment (INCAT) score. In CSF, multiplex PEA analysis revealed up-regulation of IL8 in GBS compared to CIDP and HC respectively, and CIDP compared to HC. In addition, levels of IL2RA were upregulated in GBS compared to both HC and CIDP, SELE in GBS compared to HC, and ITGAM, IL6, and NRP1 in GBS compared to CIDP. In plasma, levels of MMP3, THBD and ITGAM were upregulated in CIDP compared to HC. Validation of multiplex IL8 results using ELISA, revealed increased levels of IL8 in CSF in patients with GBS and CIDP versus HC and non-inflammatory polyneuropathies (NIP) respectively, as well as in PDN versus NIP and HC. Levels of IL8 in CSF correlated with impairment in the acute phase of GBS as well as outcome at 6-months follow up. IL8 in CSF is validated as a diagnostic biomarker in GBS and CIDP, and a prognostic biomarker in GBS. Multiplex PEA hereby identifies several potential biomarkers in GBS and CIDP.

Characterization of Clinical and Paraclinical Features Associated With TS-HDS Autoantibody Seropositivity

Objective To evaluate neuropathy phenotypes and clinical outcomes associated with trisulfated heparin disaccharide (TS-HDS) autoantibodies. Background TS-HDS autoantibody has been reported as a biomarker of immune-mediated neuropathy. However, studies evaluating the clinical associations of this autoantibody are limited. Design/Methods Electronic medical records were reviewed to identify TS-HDS autoantibody seropositive patients and characterize their clinical and electrodiagnostic findings. Results Seventy-seven TS-HDS-IgM seropositive (titer range 9000-350,000) patients were identified (50 females; median age of onset was 48 years (range 9-83 years). Eleven patients were also positive for FGFR3-IgG (titer range 4000-19,000). 70% (54/77) had clinical/paraclinical evidence of neuropathy (54/77, 70% of TS-HDS-IgM alone; 10/11, 91% of TS-HDS-IgM with coexisting FGFR3-IgG). The managing physician characterized an immune-mediated neuropathy in 30% (23/77) and 54% (6/11) of the TS-HDS-IgM only and TS-HDS-IgM with coexisting FGFR3-IgG seropositive patients, respectively. Small fiber neuropathy presented in 58% (45/77) and 63% (7/11) of TS-HDS-IgM only, and both antibodies seropositive patients, respectively. Length-dependent neuropathy was the most common neuropathy phenotype amongst TS-HDS IgM (43/54, 80%) and dual seropositive cases (7/11, 63%). Forty-one (53%) patients received immunotherapy, predominantly: IVIG (n = 37), IV solumedrol (n = 7), oral prednisone (n = 14), and mycophenolate mofetil (n = 12). Among these, 43% (15/35) with TS-HDS-IgM seropositivity alone had improvement in inflammatory neuropathy cause and treatment (INCAT) disability score or modified Rankin Scale (mRS), while 33% (2/6) of patients with dual seropositivity had INCAT and mRS improvement. TS-HDS-IgM titers had low discriminative ability to identify immunotherapy response with an AUC of 0.621. Conclusions Neuropathy associations and clinical phenotypes amongst TS-HDS-IgM seropositive cases are variable. Furthermore, only a minority of cases are immunotherapy responsive, limiting the value of this biomarker in identifying immune-mediated neuropathies.

Efficacy of rituximab in anti-myelin-associated glycoprotein demyelinating polyneuropathy: Clinical, hematological and neurophysiological correlations during 2 years of follow-up.

We evaluated the clinical and neurophysiological efficacy of rituximab (RTX) in a neurophysiologically homogeneous group of patients with monoclonal gammopathy and immunoglobulin M (IgM) anti-myelin-associated glycoprotein antibody (anti-MAG) demyelinating polyneuropathy. Twenty three anti-MAG-positive polyneuropathic patients were prospectively evaluated before and for 2 years after treatment with RTX 375 mg/m2 . The Inflammatory Neuropathy Cause and Treatment (INCAT) disability scale (INCAT-ds), modified INCAT sensory score (mISS), Medical Research Council sum score, Patients' Global Impression of Change scale were used, IgM levels were assessed and extensive electrophysiological examinations were performed before (T0) and 1 year (T1) and 2 years (T2) after RTX treatment. At T1 and T2 there was a significant reduction from T0 both in mISS and in INCAT-ds, with a pvalue < 0.001 in the inferential Friedman's test overall analysis. Ulnar nerve Terminal Latency Index and distal motor latency significantly changed from T0 to T1 and in the overall analysis (p=0.001 and p=0.002), and ulnar nerve sensory nerve action potential (SNAP) amplitude was significantly increased at T2 from T1, with a pvalue < 0.001 in the overall analysis. Analysis of the receiver-operating characteristic curves showed that a 41.8% increase in SNAP amplitude in the ulnar nerve at T2 from T0 was a fair predictor of a mISS reduction of ≥2 points (area under the curve 0.85; p=0.005; sensitivity: 90.9%, specificity: 83.3%). This study suggests that RTX is effective in patients with clinically active demyelinating anti-MAG neuropathy over 2 years of follow-up, and that some neurophysiological variables might be useful for monitoring this efficacy.

Neurofilament light chain and total tau in the differential diagnosis and prognostic evaluation of acute and chronic inflammatory polyneuropathies.

Background and PurposeTo investigate the diagnostic and prognostic value of axonal injury biomarkers in patients with inflammatory polyneuropathies.MethodsNeurofilament light chain (NfL) and total tau (T‐tau) were measured in the cerebrospinal fluid (CSF) and plasma in 41 patients with Guillain–Barré syndrome (GBS), 32 patients with chronic inflammatory demyelinating polyneuropathy (CIDP), 10 with paraproteinemia‐related demyelinating polyneuropathy (PDN), and 8 with multifocal motor neuropathy (MMN), in comparison with 39 disease‐free controls and 59 other controls. Outcome was measured with the GBS‐disability score (GBS‐ds) or Inflammatory Neuropathy Cause and Treatment (INCAT) disability score.ResultsNeurofilament light chain levels in CSF and plasma were higher in GBS, CIDP, and PDN vs. disease‐free controls. Patients with MMN had higher NfL levels in plasma vs. disease‐free controls, but lower levels in CSF and plasma vs. patients with amyotrophic lateral sclerosis (ALS).T‐tau levels in plasma were higher in GBS, CIDP, PDN, and MMN vs. all control groups.Neurofilament light chain levels in CSF and plasma in patients with GBS correlated with GBS‐ds, as higher levels were associated with inability to run after 6 and 12 months. NfL levels in CSF and plasma in CIDP did not correlate significantly with outcome.ConclusionsAcute and chronic inflammatory neuropathies are associated with an increase in levels of NfL in CSF and plasma, but NfL is validated as a prognostic biomarker only in GBS. NfL could be used in differentiating patients with MMN from ALS. T‐tau in plasma is a novel biomarker that could be used in a diagnostic assessment of patients with acute and chronic inflammatory polyneuropathies.

Inflammatory Neuropathy Cause and Treatment (INCAT) Scale for the assessment of disability level in patients with chronic inflammatory demyelinating polyneuropathy: linguocultural ratification in Russia

Background. Chronic inflammatory demyelinating polyneuropathy (CIDP) is a treatable dysimmune polyneuropathy. An objective response for pathogenic therapy is essential in diagnosis and management of CIDP. For proper assessment of patient’s complaints and evaluation of disease progression, it is recommended to use validated scales and questionnaires. The paper presents the results of the first step of Inflammatory Neuropathy Cause and Treatment (INCAT) validation in patients with CIDP.Objective: the development of the Russian version of the INCAT scale and its linguocultural ratification.Materials and methods. 15 patients with definite CIDP (according to EFNS/PNS criteria) were enrolled. Linguocultural ratification was conducted according to the standard protocol.Results. The Russian version of the INCAT scale was developed.Conclusion. We conducted the first stage of INCAT scale validation in patients with CIDP.

Retrospective analysis of response to rituximab in chronic inflammatory demyelinating polyneuropathy refractory to first‐line therapy

Few case reports/series describe the efficacy of rituximab in refractory chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), which is preferred in the presence of anti-nodal/paranodal antibodies. We aimed at evaluating the clinical response to rituximab in a subset of patients with refractory CIDP for whom the anti-nodal/paranodal antibodies status was unknown, as not available in Iran. We retrospectively analyzed the response to rituximab in 14 Iranian patients with refractory CIDP (3 children, 11 adults), in whom the anti-nodal/paranodal antibodies status was unknown. The subjects were evaluated with the Medical Research Council (MRC) sum score (MRCSS), Inflammatory Neuropathy Cause and Treatment (INCAT) disability scores, and electrophysiology, before and after treatment. Mean age was 34.4 ± 20.7 years, disease duration pre-rituximab treatment was 27.8 ± 18.8 (range: 6-60) months, and mean follow-up duration was 18.5 ± 11.0 (range: 4-36) months. Considering the INCAT sum score, one worsened during post-rituximab treatment, and three patients did not change. Considering MRCSS, notably, four patients achieved normalization of their MRCSS. Regarding the corticosteroid dose, two patients could discontinue prednisolone. As rated by a pre-defined scoring system, nerve conduction parameters improved significantly post-rituximab in the treated cohort (P=.006). All patients tolerated rituximab infusions without adverse effects. Rituximab may be effective in refractory CIDP, even though worsening may occur in some patients. Anti-nodal/paranodal antibodies assay, when available, and other criteria may help drive therapeutic decision-making on rituximab as second-line treatment.

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 (Emax) 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.

P 46. Assessment of individualized treatment decisions for intravenous immunoglobulin therapy in patients with chronic immune-mediated neuropathies: observational study design and progress

Introduction. Chronic immune-mediated neuropathies such as chronic inflammatory demyelinating polyneuropathy (CIDP) and multifocal motor neuropathy (MMN) are associated with immune mediated peripheral nerve damage and neurological deficits. Randomized, controlled clinical trials have demonstrated the effectiveness of human intravenous immunoglobulin (IVIG) for these conditions. IVIG is considered a treatment of choice for both disorders. German and EFNS/PNS guidelines recommend individualization of IVIG therapy during treatment for CIDP and MMN. However, there is a lack of documentation of individualized dosing in real-world practice. Objective. This study is designed to determine the patterns of use of 10% IVIG in real-world clinical practice and identify the factors driving treatment decisions for patients with CIDP or MMN. Methods. The study is non-interventional, longitudinal, multicenter design. Primary data collected will be physicians“ practice patterns, demographics, treatment regimens and tolerability of 10% IVIG. Adult patients (n=150) diagnosed with CIDP or MMN and with current or prospective therapy with 10% IVIG will be eligible for the study. Approximately 40 sites in Germany will participate in the study. The planned recruitment period for the study is 18 months starting in first half of 2021. Results. According to the study protocol, patient demographics, medical and disease history and concomitant medication are to be assessed at baseline. Data will be collected at the baseline visit and at each infusion visit (approximately every 3 weeks as scheduled for routine care) for up to 18 months . In addition, the study will include an initial , cross-sectional, quantitative survey for participating physicians on their current practice patterns for CIDP and MMN. The survey will include assessment of initial therapy choices, IVIG dosing, outcome measures, dosing reductions and treatment schemes for relapses. The criteria used for decisions about initiation, continuation and individualization of IVIG treatment (dosing, intervals, co-medication) will be recorded at each visit. Physicians are also requested to provide the Inflammatory Neuropathy Cause and Treatment (INCAT) Disability Score at baseline and other study visits, if these scores are routinely determined. The physician-assessed Clinical Global Impression of Improvement (CGI-I) is to be performed at all visits. The potential impact of the COVID-19 pandemic on an individual subject“s treatment algorithm will also be captured in the electronic data capture system . To assess safety, serious adverse events and adverse drug reactions will be evaluated at each visit. Conclusions. Results from this clinical trial will allow identification of the factors driving treatment decisions by physicians utilizing 10% IVIG to treat patients with CIDP or MMN as part of their clinical routine and allow assessment of the influence of patient-reported outcomes and objective clinical measures.

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

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

Prospective analysis of disability and quality of life in patients with chronic inflammatory demyelinating polyradiculoneuropathy.

Even treated chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) continues to pose a significant burden in patients' everyday functioning and may continuously affect their quality of life (QoL). The aims of our prospective study were to analyze health-related QoL in CIDP patients during a 1-year follow-up period in real-life settings and to compare QoL changes with changes in disability and with patient impression of change. The study comprised 59 patients diagnosed with CIDP. SF-36 questionnaire was applied in order to evaluate patients' QoL. Inflammatory neuropathy cause and treatment (INCAT) disability scale was used to assess patients' functionality. The second question from the SF-36 questionnaire was used as an estimation of the patient impression of change (PIC) after 1 year. SF-36 scores did not change over time in the group as a whole. According to INCAT disability scores, worsening was registered in 24 (40%) patients and improvement in 8 (14%). Fifteen (25%) patients reported worsening and the same number reported improvement, according to PIC. Concordant results on INCAT and PIC were registered in 49% of patients. Pooled SF-36 scores moderately correlated with pooled INCAT disability scores (rho = - 0.27 to - 0.59, p < 0.01). One-year changes of SF-36 scores did not differ when compared to different INCAT outcomes (worsening, stable, improvement). On the other hand, significant changes of SF-36 scores in different outcome groups according to PIC (worsening, stable, improvement) were noted (p < 0.01). INCAT, PIC, and SF-36 are complementary outcome measures that provide neurologists with useful items of information. We propose complementary use of these scales in CIDP patients in everyday clinical practice in order to detect worsening of the disease and/or of related symptoms on time.

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.

Psychometric longitudinal evaluation of the Chronic Acquired Polyneuropathy Patient-Reported Index (CAPPRI) in patients with chronic inflammatory demyelinating polyneuropathy.

We studied the performance of a 15-item, health-related quality-of-life polyneuropathy scale in a longitudinal study of patients with chronic inflammatory demyelinating polyneuropathy (CIDP). Sixty-one patients with CIDP completed the Chronic Acquired Polyneuropathy Patient-Reported Index (CAPPRI) scale and Patient Impression of Change (PIC) at baseline and follow-up visits. Clinicians completed Inflammatory Neuropathy Cause and Treatment (INCAT) disability scores at baseline and follow-up visits. Conventional and modern psychometric analyses were performed on the completed forms. CAPPRI was psychometrically stable between visits without significant difference in response pattern between visits 1 and 2 (paired t-test P = .72). There was strong correlation between changes in INCAT and changes in CAPPRI scores between two visits (rho = 0.6, P < .001). In addition, we showed robust CAPPRI effect sizes between PIC categories. We demonstrated psychometric stability and construct longitudinal validity of CAPPRI.

The Bruton tyrosine kinase inhibitor ibrutinib improves anti-MAG antibody polyneuropathy

ObjectiveTo assess whether neuropathy with anti-myelin-associated glycoprotein (MAG) antibody may improve after treatment with ibrutinib, an oral inhibitor of Bruton tyrosine kinase, we prospectively treated with ibrutinib a cohort of 3 patients with anti-MAG neuropathy and Waldenström macroglobulinemia (WM).MethodsAll 3 patients underwent bone marrow biopsy showing WM, with MYD88L265P mutated and CXCR4S338X wild type, and were started on ibrutinib 420 mg/die. Patients were assessed at baseline, at 3-6-9 months, and at 12 months in 2 patients with a longer follow-up, using Inflammatory Neuropathy Cause and Treatment (INCAT) Disability Score, INCAT sensory sum score, and Medical Research Council sum score. The modified International Cooperative Ataxia Rating Scale was performed in 2 patients, whereas it was not used in the patient with Parkinson disease as a major comorbidity. Responders were considered the patients improving by at least one point in 2 clinical scales.ResultsAll the patients reported an early and subjective benefit, consistent with the objective improvement, especially of the sensory symptoms as shown by clinical scales. Treatment was well tolerated.ConclusionThese preliminary data point to a possible efficacy of ibrutinib in anti-MAG antibody neuropathy, which is the most common disabling paraproteinemic neuropathy, where active treatment is eagerly needed.Classification of evidenceThis study provides Class IV evidence that for patients with anti-MAG antibody neuropathy, ibrutinib improves neuropathy symptoms.