Immunosuppressive treatment in refractory chronic inflammatory demyelinating polyradiculoneuropathy. A nationwide retrospective analysis

Prospective open-label trial with rituximab in patients with chronic inflammatory demyelinating polyradiculoneuropathy not responding to conventional immune therapies

BACKGROUND

To evaluate the efficacy of rituximab in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) patients not responding to conventional immune therapies.

METHODS

An open-label, prospective exploratory study was conducted with intravenous rituximab on 17 CIDP patients who had not responded to at least two first-line therapies. The primary endpoint was to determine the proportion of patients who showed improvement 6 months after rituximab therapy. The percentage of responders to rituximab, along with a 95% CI, was reported and compared with the 30% response rate after other immunosuppressive drugs previously documented in the literature.

RESULTS

13 of the 17 treated patients (76.5%) showed improvement at 6 months (95% CI 50.1 to 93.2). Among the 14 patients who completed the 12-month follow-up (2 were lost to follow-up after showing improvement at months 8 and 10, and 1 deteriorated at 6 months), 13 (92.9%) demonstrated improvement at 12 months (95% CI 66.1 to 99.8). Nerve conduction parameters improved by at least 20% in two nerves in 6 out of 15 (40%) patients at 6 months and in 7 out of 13 (53.9%) at 12 months. None of the treated patients withdrew from the study due to side effects. There was a significant reduction of circulating CD19+ cells 15 days, 2, 6 and 12 months after treatment.

CONCLUSION

Rituximab seems to be a safe therapy in most patients with CIDP not responding to conventional immune therapies. The high percentage of patients who improved in this study suggests a possible positive effect of rituximab which is worth investigating in future randomised controlled clinical trials.

TRIAL REGISTRATION NUMBER

NCT05877040.

Effectiveness and safety of rituximab in autoimmune nodopathy: a single-center cohort study

Autoimmune nodopathy is a peripheral neuropathy characterized by acquired motor and sensory deficit with autoantibodies against the node of Ranvier or paranodal region in the peripheral nervous system. The clinical and pathological characteristics of the disease are distinct from that of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), and the standard treatment for CIDP is partially effective. Rituximab is a chimeric monoclonal antibody which binds and depletes B cells in peripheral blood. This prospective observational study included 19 patients with autoimmune nodopathy. Participants received intravenous rituximab treatment 100 mg the first day and 500 mg the next day and given every 6 months. The Inflammatory Neuropathy Cause and Treatment (INCAT) disability score, Inflammatory Rasch-Built Overall Disability Scale (I-RODS), Medical Research Council (MRC) sum score, and Neuropathy Impairment Score (NIS) were collected at entry and before the rituximab infusion every 6 months. At the last visit, 94.7% (18/19) of the patients showed clinical improvement on either the INCAT, I-RODS, MRC, or NIS scale. After the first infusion, 9 patients (47.7%) showed improvement on the INCAT score, and 11 patients (57.9%) on cI-RODS. In patients who received more than one rituximab infusion, the improvement of INCAT score and cI-RODS at the last assessment was higher than that after the first infusion. We also observed tapered or withdrawn concomitant oral medications in these patients.

Sex differences in Guillain Barré syndrome, chronic inflammatory demyelinating polyradiculoneuropathy and experimental autoimmune neuritis

Guillain Barré syndrome (GBS) and its variants, and chronic inflammatory demyelinating polyradiculoneuropathy (CIDP and its variants, are regarded as immune mediated neuropathies. Unlike in many autoimmune disorders, GBS and CIDP are more common in males than females. Sex is not a clear predictor of outcome. Experimental autoimmune neuritis (EAN) is an animal model of these diseases, but there are no studies of the effects of sex in EAN. The pathogenesis of GBS and CIDP involves immune response to non-protein antigens, antigen presentation through non-conventional T cells and, in CIDP with nodopathy, IgG4 antibody responses to antigens. There are some reported sex differences in some of these elements of the immune system and we speculate that these sex differences could contribute to the male predominance of these diseases, and suggest that sex differences in peripheral nerves is a topic worthy of further study.

Cyclophosphamide for Treatment of Refractory Chronic Inflammatory Demyelinating Polyradiculoneuropathy: A Systematic Review and Meta-analysis

PURPOSE

This study evaluates the tolerability and efficacy of cyclophosphamide (CYC) for the treatment of refractory chronic inflammatory demyelinating polyradiculoneuropathy (CIDP).

METHODS

We searched PubMed, Embase, Cochrane Library, and 2 Chinese databases (Chinese National Knowledge Infrastructure and SinoMed) for studies published between database inception and September 30, 2021. Articles obtained using the appropriate keywords were independently selected by 2 reviewers on the basis of the established inclusion and exclusion criteria.

FINDINGS

In total, 240 records that were eventually curtailed to 13 studies with 83 patients were retrieved and subsequently included in this evaluation. All 13 studies were included in the systematic review, 7 of which were included in the meta-analysis. The pooled estimate of the response rate was 68% (95% CI, 45%-90%). The pooled estimate of the adverse reaction rate was 8% (95% CI, 0%-15%). The disease duration before the first CYC treatment was negatively correlated with the reduction in the modified Rankin Scale score (r = -0.76, P < 0.001). However, the response rates did not differ significantly between patients of different sexes (P = 0.716) or between patients who received and those who did not receive concurrent glucocorticoids (P = 0.617).

IMPLICATIONS

CYC might be a recommended therapeutic option for patients with refractory CIDP, especially those who are unable to accept rituximab treatment. Earlier CYC treatment yields better therapeutic outcomes in patients with refractory CIDP without CYC-related contraindications.

Therapeutic Monoclonal Antibody Therapies in Chronic Autoimmune Demyelinating Neuropathies

Autoimmune diseases of the peripheral nervous system have so far been treated mainly with exogenous high-dose intravenous immunoglobulins (IVIg), that act through several mechanisms, including neutralization of pathogenic autoantibodies, modulation of lymphocyte activity, interference with antigen presentation, and interaction with Fc receptors, cytokines, and the complement system. Other therapeutic strategies have recently been developed, in part to address the increasing shortage of IVIg, prime among which is the use of B cell depleting monoclonal antibodies, or small molecule inhibitors targeting the B-cell specific kinases. Rituximab, a chimeric monoclonal antibody against CD20 + B lymphocytes, is currently the most used, especially in anti-MAG antibody neuropathy and autoimmune neuropathies with antibodies to nodal/paranodal antigens that are unresponsive to IVIg. After several reports of its efficacy in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), rituximab is currently under investigation in three Phase 2 trials in CIDP. In addition, the possible role of complement activation in the pathogenesis of chronic autoimmune neuropathies has brought into consideration drugs that can block the complement cascade, such as eculizumab, a monoclonal antibody already assessed in acute polyradiculoneuropathies, and approved for myasthenia gravis. Preliminary data on eculizumab in multifocal motor neuropathy have been published, but randomized controlled studies are pending. Moreover, the neonatal Fc receptor, that recycles IgGs by preventing their lysosome degradation, is an important and attractive pharmacological target. Antibodies against FcRn, which reduce circulating IgG (both pathogenic and non-pathogenic) have been developed. The FcRn blocker efgartigimod, a humanized IgG1-derived Fc fragment, which competitively inhibits the FcRn, has recently been approved for the treatment of myasthenia gravis and is currently under investigation in CIDP. In addition, the anti-human FcRn monoclonal antibody rozanolixizumab is currently being assessed in phase 2 trials in CIDP. However, none of the abovementioned monoclonal antibodies is currently approved for treatment of any immune-mediated neuropathies. While more specific and individualized therapies are being developed, the possibility of combined treatments targeting different pathogenic mechanisms deserves consideration as well.

Dose-dependent immunomodulatory effects of bortezomib in experimental autoimmune neuritis

Proteasome inhibition with bortezomib has been reported to exert an immunomodulatory action in chronic autoimmune neuropathies. However, bortezomib used for the treatment of multiple myeloma induces a painful toxic polyneuropathy at a higher concentration. Therefore, we addressed this controversial effect and evaluated the neurotoxic and immunomodulatory mode of action of bortezomib in experimental autoimmune neuritis. Bortezomib-induced neuropathy was investigated in Lewis rats using the von Frey hair test, electrophysiological, qPCR and histological analyses of the sciatic nerve as well as dorsal root ganglia outgrowth studies. The immunomodulatory potential of bortezomib was characterized in Lewis rats after experimental autoimmune neuritis induction with P2_53-78 peptide. Clinical, electrophysiological, histological evaluation, von Frey hair test, flow cytometric and mRNA analyses were used to unravel the underlying mechanisms. We defined the toxic concentration of 0.2 mg/kg bortezomib applied intraperitoneally at Days 0, 4, 8 and 12. This dosage induces a painful toxic neuropathy but preserves axonal regeneration in vitro. Bortezomib at a concentration of 0.05 mg/kg significantly ameliorated experimental autoimmune neuritis symptoms, improved experimental autoimmune neuritis-induced hyperalgesia and nerve conduction studies, and reduced immune cell infiltration. Furthermore, proteasome inhibition induced a transcriptional downregulation of Nfkb in the sciatic nerve, while its inhibitor Ikba (also known as Nfkbia) was upregulated. Histological analyses of bone marrow tissue revealed a compensatory increase of CD138⁺ plasma cells. Our data suggest that low dose bortezomib (0.05 mg/kg intraperitoneally) has an immunomodulatory effect in the context of experimental autoimmune neuritis through proteasome inhibition and downregulation of nuclear factor 'kappa-light-chain-enhancer' of activated B-cells (NFKB). Higher bortezomib concentrations (0.2 mg/kg intraperitoneally) induce sensory neuropathy; however, the regeneration potential remains unaffected. Our data empathizes that bortezomib may serve as an attractive treatment option for inflammatory neuropathies in lower concentrations.

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.

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).

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.

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).

Treatment response to cyclophosphamide, rituximab, and bortezomib in chronic immune-mediated sensorimotor neuropathies: a retrospective cohort study

Background:

Up to 20% of patients with chronic immune-mediated sensorimotor neuropathies (CIN) do not respond adequately to first-line therapies. However, studies on further treatment are scarce.

Methods:

We analyzed retrospectively 200 CIN patients regarding disease characteristics and response to therapy with cyclophosphamide (CYP), rituximab (RTX), and bortezomib (BTZ). Treatment response was defined as improvement or stabilization of inflammatory neuropathy cause and treatment overall disability score (INCAT-ODSS).

Results:

A total of 48 of 181 patients (26.5%) received therapy with CYP, RTX, or BTZ. The most frequently and first used therapy was CYP (69%). More than 40% of patients needed a second or third treatment. Overall, 71 treatments were applied in 48 patients. The combination of up to all three treatments enhanced the response-rate to 90%. Treatment within 24 months after initial diagnosis resulted in significantly higher response rate than late treatment (79% versus 50 %, p = 0.04, χ²-test, n = 46) and in lower disability in long-term follow up (INCAT-ODSS 3.8 versus 5.8, p = 0.02, t-test, n = 48). Patients with Lewis-Sumner syndrome (n = 9) and autoantibody mediated neuropathies (n = 13) had excellent response rates after treatment with RTX (90–100%). In contrast, typical chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) showed a response rate of 64% in CYP, 64% in RTX, and 75% in BTZ.

Conclusion:

Treatment with CYP, RTX, or BTZ was effective in this cohort of CIN refractory to first-line treatment. Our data increase evidence for an early use of these therapies. High efficacy of RTX in Lewis-Sumner syndrome in contrast to typical CIDP suggests a distinct pathophysiology.

Chronic inflammatory demyelinating polyradiculoneuropathy: can a diagnosis be made in patients not fulfilling electrodiagnostic criteria?

BACKGROUND AND PURPOSE

The aim was to identify the clinical and diagnostic investigations that may help to support a diagnosis of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) in patients not fulfilling the European Federation of Neurological Societies and Peripheral Nerve Society (EFNS/PNS) electrodiagnostic criteria.

METHODS

The data from patients with a clinical diagnosis of CIDP included in a national database were retrospectively reviewed.

RESULTS

In all, 535 patients with a diagnosis of CIDP were included. This diagnosis fulfilled the EFNS/PNS criteria in 468 patients (87.2%) (definite in 430, probable in 33, possible in three, while two had chronic immune sensory polyradiculopathy). Sixty-seven patients had a medical history and clinical signs compatible with CIDP but electrodiagnostic studies did not fulfill the EFNS/PNS criteria for CIDP. These patients had similar clinical features and frequency of abnormal supportive criteria for the diagnosis of CIDP compared to patients fulfilling EFNS/PNS criteria. Two or more abnormal supportive criteria were present in 40 (61.2%) patients rising to 54 (80.6%) if a history of a relapsing course as a possible supportive criterion was also included. Increased cerebrospinal fluid proteins and response to immune therapy most frequently helped in supporting the diagnosis of CIDP. Response to therapy was similarly frequent in patients fulfilling or not EFNS/PNS criteria (87.3% vs. 85.9%).

CONCLUSIONS

Patients with a clinical diagnosis of CIDP had similar clinical findings, frequency of abnormal supportive criteria and response to therapy compared to patients fulfilling EFNS/PNS criteria. The presence of abnormal supportive criteria may help in supporting the diagnosis of CIDP in patients with a medical history and clinical signs compatible with this diagnosis but non-diagnostic nerve conduction studies.

Efficacy and Safety of Rituximab in Refractory CIDP With or Without IgG4 Autoantibodies (RECIPE): Protocol for a Double-Blind, Randomized, Placebo-Controlled Clinical Trial

BACKGROUND

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an immune-mediated peripheral neuropathy that is currently classified into several clinical subtypes, which are presumed to have different pathogenic mechanisms. Recently, studies identified a subgroup of patients with CIDP who were positive for IgG4 autoantibodies against paranodal proteins, such as neurofascin-155 and contactin-1, who respond poorly to first-line therapies for typical CIDP, including intravenous immunoglobulin therapy.

OBJECTIVE

This study aims to evaluate the efficacy and safety of intravenous rituximab according to IgG4 autoantibody status in patients with refractory CIDP.

METHODS

The Evaluation of the Efficacy and Safety of Rituximab in Refractory CIDP Patients with IgG4 Autoantibodies in the Exploratory Clinical (RECIPE) trial consists of 2 cohorts: a multicenter, placebo-controlled, randomized study cohort of 15 patients with IgG4 autoantibody-positive CIDP (rituximab:placebo = 2:1) and an open-label trial cohort of 10 patients with antibody-negative CIDP. The primary endpoint is improvement in functional outcome assessed using the adjusted Inflammatory Neuropathy Cause and Treatment Disability Scale score at 26, 38, or 52 weeks after the start of treatment with rituximab in patients with CIDP and anti-paranodal protein antibodies. Secondary outcome measures include grip strength, manual muscle testing sum scores, results of nerve conduction studies, and other functional scales.

RESULTS

We plan to enroll 25 cases for the full analysis set. Recruitment is ongoing, with 14 patients enrolled as of January 2020. Enrollment will close in September 2020, and the study is planned to end in December 2021.

CONCLUSIONS

This randomized controlled trial will determine if rituximab is safe and effective in patients with anti-paranodal antibodies. An open-label study will provide additional data on the effects of rituximab in patients with antibody-negative CIDP. The results of the RECIPE trial are expected to provide evidence for the positioning of rituximab as a pathogenesis-based therapeutic for refractory CIDP.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03864185, https://clinicaltrials.gov/ct2/show/NCT03864185 ; The Japan Registry of Clinical Trials jRCT2041180037, https://jrct.niph.go.jp/en-latest-detail/jRCT2041180037.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/17117.

Rituximab in refractory chronic inflammatory demyelinating polyneuropathy

INTRODUCTION

Chronic inflammatory demyelinating polyneuropathy (CIDP) is a disorder in which early effective treatment is important to minimize disability from axonal degeneration. It has been suggested that some patients with CIDP may benefit from rituximab therapy, but there is no definitive evidence for this.

METHODS

Baseline and post-rituximab-therapy neuromuscular Medical Research Council (MRC) sum scores, Inflammatory Neuropathy Cause and Treatment (INCAT) disability score, and functional status were assessed in 11 patients with refactory CIDP.

RESULTS

The MRC sum score, INCAT disability score, and functional status improved in all patients after rituximab therapy.

DISCUSSION

Our study provides evidence of the efficacy of rituximab therapy in at least some patients with CIDP. A placebo-controlled study to assess the effectiveness of rituximab therapy in CIDP with and without nodal antibodies is required to identify disease markers that predict responsiveness.

Chronic inflammatory demyelinating polyneuropathy: Plasmapheresis or cyclosporine can be good treatment options in refractory cases

Childhood chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a rare condition, and the optimal treatment strategy is not well established, especially in refractory cases. We analyzed the clinical features and treatment outcomes of 14 cases of childhood CIDP with more than 12 months of follow-up. Of the 14 cases, 10 cases were considered refractory to the conventional first-line treatment. In the monophasic group (n = 6), plasmapheresis resulted in a better treatment response than did IVIG. Monophasic refractory cases (n = 4) were especially responsive to plasmapheresis. In the polyphasic group (n = 8), IVIG and plasmapheresis had comparable effects. Among them six polyphasic patients were refractory to the first-line treatment options and received additional immunosuppressants. Four treatment-refractory polyphasic patients received cyclosporine and achieved successful disease control. With regard to the long-term outcomes, six patients showed minimal symptoms and no relapse within 6 months. Our results suggest that early administration of plasmapheresis in a monophasic course and cyclosporine in a polyphasic course may be effective treatment options for refractory childhood CIDP.

FTY720 controls disease severity and attenuates sciatic nerve damage in chronic experimental autoimmune neuritis

Background

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an autoimmune-mediated inflammatory disease of the peripheral nervous system characterized by a response directed against certain myelin proteins and for which therapies are limited. Previous studies have suggested a beneficial role of FTY720, a sphingosine 1-phosphate (S1P) receptor agonist, known to deplete lymphocytes from the peripheral blood by sequestering them into lymph nodes, in the treatment of experimental autoimmune neuritis (EAN). Therefore, we investigated whether FTY720 is also beneficial in chronic experimental autoimmune neuritis (c-EAN), a recently developed rat model mimicking human CIDP.

Methods

c-EAN was induced in Lewis rats by immunization with S-palm P0(180–199) peptide. Rats were treated with FTY720 (1 mg/kg) or vehicle intraperitoneally once daily from the onset of clinical signs for 18 days; clinical signs were assessed daily until 60 days post-immunization (dpi). Electrophysiological and histological features were examined at different time points. We also evaluated the serum levels of different pro- and anti-inflammatory cytokines by ELISA or flow cytometry at 18, 40, and 60 dpi.

Results

Our data demonstrate that FTY720 decreased the severity and abolished the chronicity of the disease in c-EAN rats. Therapeutic FTY720 treatment reversed electrophysiological and histological anomalies, suggesting that myelinated fibers were subsequently preserved, it inhibited macrophage and IL-17⁺ cell infiltration in PNS, and it significantly reduced circulating pro-inflammatory cytokines.

Conclusions

FTY720 treatment has beneficial effects on c-EAN, a new animal model mimicking human CIDP. We have shown that FTY720 is an effective immunomodulatory agent, improving the disease course of c-EAN, preserving the myelinated fibers, attenuating the axonal degeneration, and decreasing the number of infiltrated inflammatory cells in peripheral nerves. These data confirm the interest of testing FTY720 or molecules targeting S1P in human peripheral neuropathies.

Electronic supplementary material

The online version of this article (10.1186/s12974-019-1441-4) contains supplementary material, which is available to authorized users.

Rituximab in neurological disease: principles, evidence and practice

Rituximab is a widely used B-cell-depleting monoclonal antibody. It is unlicensed for use in neurological disorders and there are no treatment guidelines. However, as a rapidly acting, targeted therapy with growing evidence of efficacy and tolerability in several neuroinflammatory disorders, it is an attractive alternative to conventional immunomodulatory medications. This practical review aims to explain the basic principles of B-cell depletion with therapeutic monoclonal antibodies. We present the evidence for using rituximab in neurological diseases, and describe the practical aspects of prescribing, including dosing, monitoring, safety, treatment failure and its use in special circumstances such as coexisting viral hepatitis, pregnancy and lactation. We provide an administration guide, checklist and patient information leaflet, which can be adapted for local use. Finally, we review the safety data of rituximab and ocrelizumab (a newer and recently licensed B-cell-depleting therapy for multiple sclerosis) and suggest monitoring and risk reduction strategies.

History, Diagnosis, and Management of Chronic Inflammatory Demyelinating Polyradiculoneuropathy

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is probably the best recognized progressive immune-mediated peripheral neuropathy. It is characterized by a symmetrical, motor-predominant peripheral neuropathy that produces both distal and proximal weakness. Large-fiber abnormalities (weakness and ataxia) predominate, whereas small-fiber abnormalities (autonomic and pain) are less common. The pathophysiology of CIDP is inflammatory demyelination that manifests as slowed conduction velocities, temporal dispersion, and conduction block on nerve conduction studies and as segmental demyelination, onion-bulb formation, and endoneurial inflammatory infiltrates on nerve biopsies. Although spinal fluid protein levels are generally elevated, this finding is not specific for the diagnosis of ClDP. Other neuropathies can resemble CIDP, and it is important to identify these to ensure correct treatment of these various conditions. Consequently, metastatic bone surveys (for osteosclerotic myeloma), serum electrophoresis with immunofixation (for monoclonal gammopathies), and human immunodeficiency virus testing should be considered for testing in patients with suspected CIDP. Chronic inflammatory demyelinating polyradiculoneuropathy can present as various subtypes, the most common being the classical symmetrical polyradiculoneuropathy and the next most common being a localized asymmetrical form, multifocal CIDP. There are 3 well-established, first-line treatments of CIDP-corticosteroids, plasma exchange, and intravenous immunoglobulin-with most experts using intravenous immunoglobulin as first-line therapy. Newer immune-modulating drugs can be used in refractory cases. Treatment response in CIDP should be judged by objective measures (improvement in the neurological or electrophysiological examination), and treatment needs to be individualized to each patient.

The clinical features of combined central and peripheral demyelination in Chinese patients

BACKGROUND

Combined central and peripheral demyelination (CCPD) is rare and has never been reported as a spectrum disease in Han Chinese population.

OBJECTIVES

To study the clinical features of CCPD in Han Chinese patients.

METHODS

Twenty-two CCPD patients were selected from 788 demyelination cases. We reviewed and compared the clinical manifestation, laboratory data, electrophysiological examination, MRI and the prognosis.

RESULTS

CCPD patients presented with sensory disturbance (86.4%), plegia (77.3%), cranial nerve involvement (77.3%), abnormal deep tendon reflexes (72.7%). CSF data showed increased CSF protein in 81% patients. Oligoclonal IgG bands (OB) were negative. Cortical or juxtacortical, periventricular, infratentorial lesions, thoracic and cervical spinal cord were mostly affected. Visual evoked potentials indicated optic nerves demyelinating in 50% cases. 21 CCPD patients were treated with intravenous immunoglobulin or steroids or both of them, and the efficacy was 33.3%, 54.5%, 71.4%, respectively. One case that showed no response to steroids plus intravenous immunoglobulin treatment was improved significantly after using cyclophosphamide.

CONCLUSIONS

CCPD is a spectrum disease that can't be regarded as a simple combination of MS and CIDP. A suspected CCPD should receive brain and spinal MRI as well as electrophysiological examination to obtain a precise diagnosis.

Unconventional treatments for chronic inflammatory demyelinating polyneuropathy

This article focuses on the unconventional treatments used in chronic inflammatory demyelinating polyneuropathy (CIDP). First line, evidence-based treatments for CIDP include corticosteroids, immunoglobulins and plasma exchanges. Several unproven treatments are however given in treatment-refractory disease or to reduce requirements in validated therapies for reasons of side effects/practical delivery/cost. Despite methodological issues, IFN-α, azathioprine and methotrexate have not been shown to be useful in randomized controlled trials. Cyclophosphamide, rituximab and, as final resort in highly selected cases, hematopoietic stem cell transplant may be options considered in severely disabled refractory patients. Debatably, azathioprine, methotrexate, cyclosporine and mycophenolate mofetil are still occasionally used, among others, in milder disease. Physical therapy may be of benefit in CIDP but is not systematically considered as an integral part of management strategies. Current literature relating to unconventional therapies in CIDP is reviewed here and the possible avenues that require consideration in severe refractory disease and less disabling forms are discussed.

Immunomodulatory treatment other than corticosteroids, immunoglobulin and plasma exchange for chronic inflammatory demyelinating polyradiculoneuropathy

BACKGROUND

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a disease that causes progressive or relapsing and remitting weakness and numbness. It is probably caused by an autoimmune process. Immunosuppressive or immunomodulatory drugs would be expected to be beneficial. This review was first published in 2003 and has been updated most recently in 2016.

OBJECTIVES

To assess the effects of immunomodulatory and immunosuppressive agents other than corticosteroids, immunoglobulin, and plasma exchange in CIDP.

SEARCH METHODS

On 24 May 2016, we searched the Cochrane Neuromuscular Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 4) in the Cochrane Library, MEDLINE, Embase, CINAHL, and LILACS for completed trials, and clinical trial registers for ongoing trials. We contacted the authors of the trials identified and other disease experts seeking other published and unpublished trials.

SELECTION CRITERIA

We sought randomised and quasi-randomised trials of all immunosuppressive agents, such as azathioprine, cyclophosphamide, methotrexate, ciclosporin, mycophenolate mofetil, and rituximab, and all immunomodulatory agents, such as interferon (IFN) alfa and IFN beta, in participants fulfilling standard diagnostic criteria for CIDP. We included all comparisons of these agents with placebo, another treatment, or no treatment.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. We wanted to measure the change in disability after one year as our primary outcome. Our secondary outcomes were change in disability after four or more weeks (from randomisation); change in impairment after at least one year; change in maximum motor nerve conduction velocity and compound muscle action potential amplitude after one year; and for participants who were receiving corticosteroids or intravenous immunoglobulin (IVIg), the amount of this medication given during at least one year after randomisation. Participants with one or more serious adverse events during the first year was also a secondary outcome.

MAIN RESULTS

Four trials fulfilled the selection criteria: one of azathioprine (27 participants), two of IFN beta-1a (77 participants in total) and one of methotrexate (60 participants). The risk of bias was considered low in the trials of IFN beta-1a and methotrexate but high in the trial of azathioprine. None of the trials showed significant benefit in any of the outcomes selected by their authors. The results of the outcomes which approximated most closely to the primary outcome for this review were as follows.In the azathioprine trial there was a median improvement in the Neuropathy Impairment Scale (scale range 0 to 280) after nine months of 29 points (range 49 points worse to 84 points better) in the azathioprine and prednisone treated participants compared with 30 points worse (range 20 points worse to 104 points better) in the prednisone alone group. There were no reports of adverse events.In a cross-over trial of IFN beta-1a with 20 participants, the treatment periods were 12 weeks. The median improvement in the Guy's Neurological Disability Scale (range 1 to 10) was 0.5 grades (interquartile range (IQR) 1.8 grades better to zero grade change) in the IFN beta-1a treatment period and 0.5 grades (IQR 1.8 grades better to 1.0 grade worse) in the placebo treatment period. There were no serious adverse events in either treatment period.In a parallel group trial of IFN beta-1a with 67 participants, none of the outcomes for this review was available. The trial design involved withdrawal from ongoing IVIg treatment. The primary outcome used by the trial authors was total IVIg dose administered from week 16 to week 32 in the placebo group compared with the IFN beta-1a groups. This was slightly but not significantly lower in the combined IFN beta-1a groups (1.20 g/kg) compared with the placebo group (1.34 g/kg, P = 0.75). There were four participants in the IFN beta-1a group and none in the placebo group with one or more serious adverse events, risk ratio (RR) 4.50 (95% confidence interval (CI) 0.25 to 80.05).The methotrexate trial had a similar design involving withdrawal from ongoing corticosteroid or IVIg treatment. At the end of the trial (approximately 40 weeks) there was no significant difference in the change in the Overall Neuropathy Limitations Scale, a disability scale (scale range 0 to 12), the median change being 0 (IQR -1 to 0) in the methotrexate group and 0 (IQR -0.75 to 0) in the placebo group. These changes in disability might have been confounded by the reduction in corticosteroid or IVIg dose required by the protocol. There were three participants in the methotrexate group and one in the placebo with one or more serious adverse events, RR 3.56 (95% CI 0.39 to 32.23).

AUTHORS' CONCLUSIONS

Low-quality evidence from randomised trials does not show significant benefit from azathioprine or interferon beta-1a and moderate-quality evidence from one randomised trial does not show significant benefit from a relatively low dose of methotrexate for the treatment of CIDP. None of the trials was large enough to rule out small or moderate benefit. The evidence from observational studies is insufficient to avoid the need for randomised controlled trials to discover whether these drugs are beneficial. Future trials should have improved designs, more sensitive outcome measures relevant to people with CIDP, and longer treatment durations.

A case of intravenous immunoglobulin-dependent chronic inflammatory demyelinating polyneuropathy of pure motor form responsive to mycophenolate mofetil therapy

This report concerns a case of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) with frequent treatment-dependent relapses. A 75-year-old male presented with a 2-month history of progressive weakness of the limbs with no sensory symptoms. Neurological examination revealed normal cranial nerves, MRC grade 4 power in the proximal and distal muscles of the limbs, and generalized areflexia. However, the sensory examination results, serum immunoelectrophoresis, anti-HIV antibody, and vitamins B1 and B12 levels were normal. Cervical MR imaging was unremarkable. Cerebrospinal fluid showed albuminocytologic dissociation. Nerve conduction studies demonstrated prolonged distal latencies in the bilateral median nerves and left ulnar nerve. Treatment with intravenous immunoglobulin (IVIg) infusion resulted in a marked improvement. Thereafter, the patient had been treated with repeated IVIg to maintain motor function. Subsequently, the patient fulfilled the EFNS/PNS diagnostic criteria for pure motor form of definite CIDP. Treatment with ciclosporin with the plasma trough level of 60-150 ng/ml reduced the frequency of IVIg. However, renal function began to deteriorate 94 months after the initiation of ciclosporin. The calcineurin inhibitor was replaced with mycophenolate mofetil 1,500 mg, which significantly increased the interval between infusions without further renal impairment. Therefore, mycophenolate may represent an effective alternative treatment for some IVIg-dependent CIDP patients.

Treatment of chronic inflammatory demyelinating polyneuropathy

Chronic inflammatory demyelinating polyneuropathy (CIDP) is one of the acquired demyelinating neuropathies and is considered to be immune mediated. Diagnosis is typically based on clinical history, neurologic examination, electrophysiologic studies, CSF studies, and pathologic examination. Early diagnosis and treatment is important to prevent irreversible axonal loss and optimize improvement in function. The first-line agents for treatment are intravenous immunoglobulin (IVIg), corticosteroids, and plasmapheresis, which have all been demonstrated to be effective in controlled studies. Studies have not shown a significant difference between these three treatments, and the initial choice of therapy is often based on availability, cost, ease of administration, and side effect profile. If patients do not respond to one of these agents, they may respond to one of the others and sometimes in combination. If the first-line agents are not effective, chemotherapeutic or immunosuppressive agents may be considered. There are limited controlled studies of these modalities, and they are often used in conjunction with a first-line treatment. The majority of patients require long-term therapy to maintain a response and to prevent relapse.

Novel immunotherapeutic strategies in chronic inflammatory demyelinating polyneuropathy

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a chronic immune-mediated neuropathy: it is clinically heterogeneous (relapsing-remitting form, chronic progressive form, monophasic form or CIDP having a Guillain-Barré syndrome-like onset), but potentially treatable. Although its pathophysiology remains largely unknown, CIDP is considered an immune-mediated neuropathy. Therefore, many immunotherapies have been proposed in this peripheral nervous system disorder, the most known efficient treatments being intravenous immunoglobulin, corticosteroids and plasma exchange. However, these therapies remain unsatisfactory for many patients, so numerous other immunotherapeutic strategies have been evaluated, based on their immunosuppressant or immunomodulatory potency. We have performed a large review of the literature about treatment in CIDP, with a special emphasis on novel and alternative immunotherapeutic strategies.

Immunotherapy in Peripheral Neuropathies

Immunotherapy has been investigated in a small subset of peripheral neuropathies, including an acute one, Guillain-Barré syndrome, and 3 chronic forms: chronic inflammatory demyelinating polyradiculoneuropathy, multifocal motor neuropathy, and neuropathy associated with IgM anti-myelin-associated glycoprotein. Several experimental studies and clinical data are strongly suggestive of an immune-mediated pathogenesis. Either cell-mediated mechanisms or antibody responses to Schwann cell, compact myelin, or nodal antigens are considered to act together in an aberrant immune response to cause damage to peripheral nerves. Immunomodulatory treatments used in these neuropathies aim to act at various steps of this pathogenic process. However, there are many phenotypic variants and, consequently, there is a significant difference in the response to immunotherapy between these neuropathies, as well as a need to improve our knowledge and long-term management of chronic forms.

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

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

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

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

Challenges in the treatment of chronic inflammatory demyelinating polyradiculoneuropathy

Chronic idiopathic demyelinating polyradiculoneuropathy (CIDP) is a rare disease, the most frequent one within the spectrum of the so-called "chronic immune-mediated neuropathies". Challenges in the treatment of CIDP firstly concern its diagnosis, which may be difficult, mainly for the atypical forms. Secondly, challenges encompass the choice of the first-line treatment, such as corticosteroids, intravenous immunoglobulins (IVIg), and plasma exchanges (PE) that have been proven as efficacious by several randomized controlled trials (RCT). Recent reports have focused on both different regimens of corticosteroids, and the occurrence of relapses following treatment with either corticosteroids or IVIg. These data may be helpful for the choice of the first-line treatment and may result in changing the guidelines for treatment of CIDP in clinical practice. The third and more difficult challenge is to manage long-term treatment for CIDP, since no immunomodulatory treatment has to date been proven as efficacious in this situation. Lastly, challenges in the treatment concern the choice of the best outcome measure for CIDP in RCT and clinical practice. The aim of this article is to overview the results of the more recently reported published trials for CIDP, and to give some insights for the current and future management of CIDP.

Chronic inflammatory demyelinating polyradiculoneuropathy: update on clinical features, phenotypes and treatment options

PURPOSE OF REVIEW

In this review, we focus on less recognised signs and symptoms in typical chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and on the clinical presentation, course of disease and response to treatment of the atypical CIDP phenotypes.

RECENT FINDINGS

Frequently occurring and often disabling symptoms in CIDP such as fatigue, pain and tremor have recently been emphasised, whereas autonomic dysfunction, if present, is usually mild. Sensory CIDP is probably the most frequent atypical CIDP phenotype and diagnosis can be difficult in the absence of clear demyelinating features on nerve conduction studies. The most important study comparing intravenous immunoglobulin treatment with intravenous methylprednisolone showed a lower rate of discontinuation due to inefficacy, adverse events or intolerance with intravenous immunoglobulin treatment. However, improvement after corticosteroids seems to be more long-lasting than after intravenous immunoglobulin suggesting superior long-term immunosuppressive and immunomodulating effect of corticosteroids in CIDP.

SUMMARY

Symptoms other than the classical motor and sensory symptoms can lead to significant disability in CIDP patients. Based on limited evidence from largely small retrospective case series, we conclude that atypical CIDP phenotypes often have a different course of disease and sometimes response to treatment when compared with typical CIDP. Prospective multicentre cohort studies using standardised clinical description, electrophysiological parameters and outcome measures are needed to study the natural disease course of these phenotypes including response to different treatments.

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

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

Immunomodulatory treatment other than corticosteroids, immunoglobulin and plasma exchange for chronic inflammatory demyelinating polyradiculoneuropathy

BACKGROUND

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a disease causing progressive or relapsing and remitting weakness and numbness. It is probably due to an autoimmune process. Immunosuppressive or immunomodulatory drugs would be expected to be beneficial. This review was first published in 2003 and has been most recently updated in 2013.

OBJECTIVES

We aimed to review systematically the evidence from randomised trials of immunomodulatory and immunosuppressive agents other than corticosteroids, immunoglobulin and plasma exchange for CIDP.

SEARCH METHODS

On 9 July 2012, we searched the Cochrane Neuromuscular Disease Group Specialized Register (July 2012), CENTRAL (2012, Issue 6 in The Cochrane Library), MEDLINE (January 1977 to July 2012), EMBASE (January 1980 to July 2012), CINAHL (January 1982 to July 2012) and LILACS (January 1982 to July 2012). We contacted the authors of the trials identified and other disease experts seeking other published and unpublished trials.

SELECTION CRITERIA

We sought randomised and quasi-randomised trials of all immunosuppressive agents such as azathioprine, cyclophosphamide, methotrexate, ciclosporin, mycophenolate mofetil, and rituximab and all immunomodulatory agents such as interferon alfa and interferon beta, in participants fulfilling standard diagnostic criteria for CIDP.

DATA COLLECTION AND ANALYSIS

Two authors independently selected trials, judged their risk of bias and extracted data. We wanted to measure the change in disability after one year as our primary outcome. Our secondary outcomes were change in disability after four or more weeks (from randomisation), change in impairment after at least one year, change in maximum motor nerve conduction velocity and compound muscle action potential amplitude after one year and for those participants who were receiving corticosteroids or intravenous immunoglobulin, the amount of this medication given during at least one year after randomisation. Participants with one or more serious adverse events during the first year was also a secondary outcome.

MAIN RESULTS

Four trials fulfilled the selection criteria, one of azathioprine (27 participants), two of interferon beta-1a (77 participants in total) and one of methotrexate (60 participants). The risk of bias in the two trials of interferon beta-1a for CIDP and the trial of methotrexate was assessed to be low but bias in the trial of azathioprine was judged high. None of these trials showed significant benefit in the primary outcome (measured only in the methotrexate study) or secondary outcomes selected for this review. Severe adverse events occurred no more frequently than in the placebo groups for methotrexate and interferon beta-1a, but participant numbers were low. There was no adverse event reporting in the azathioprine study.

AUTHORS' CONCLUSIONS

The evidence from randomised trials does not show significant benefit from azathioprine, interferon beta-1a or methotrexate but none of the trials was large enough to rule out small or moderate benefit. The evidence from observational studies is insufficient to avoid the need for randomised controlled trials to discover whether these drugs are beneficial. Future trials should have improved designs, more sensitive outcome measures and longer durations.