Subcutaneous immunoglobulin in CIDP and MMN: a different long-term clinical response?

Subcutaneous Immunoglobulin in Chronic Inflammatory Demyelinating Polyneuropathy: A Historical Perspective

The therapeutic administration of subcutaneous immunoglobulin (SCIg) offers various advantages over intravenous immunoglobulin (IVIg). This narrative review examines and compares SCIg versus IVIg in chronic inflammatory demyelinating polyneuropathy (CIDP). SCIg is as effective as IVIg but is better tolerated and easier to administer, as intravenous access is not required. Furthermore, SCIg administration is more convenient and cost-effective than IVIg, enabling flexible treatment scheduling at home and improving patients' overall quality of life. The availability of highly concentrated immunoglobulin G (IgG) subcutaneous solutions, such as IgPro20, a 20% IgG solution stabilized with L-proline, allows for the administration of larger volumes in a single session, while the parallel development of new technological devices enables the delivery of higher doses over a shorter time. Based on the results of the PATH study, SCIg has become a well-established therapy in CIDP. In addition to discussing the advantages of SCIg, this review summarizes the evolution of SCIg by discussing all the relevant clinical studies which have considered its use in the treatment of CIDP.

A Budget Impact Model of Maintenance Treatment of Chronic Inflammatory Demyelinating Polyneuropathy with IgPro20 (Hizentra) Relative to Intravenous Immunoglobulin in the United States

BACKGROUND

Chronic inflammatory demyelinating polyneuropathy (CIDP) is a rare, progressive autoimmune disease causing peripheral nervous system dysfunction. Guidelines recommend immunoglobulin (IG) therapy as an immunomodulatory agent in CIDP. Drawbacks and unmet needs with intravenous immunoglobulin (IVIG) include adverse effects and wear-off effects, along with the burden of administration based on site of care. Subcutaneous administration of Hizentra, a subcutaneous immunoglobulin (SCIG) reduces patient burden by allowing self-administration outside the hospital setting and has fewer adverse events (AEs).

OBJECTIVE

We aimed to compare the expected cost of treatment and the budget impact of Hizentra compared with IVIG for maintenance treatment of CIDP in the United States.

METHODS

A decision tree model was developed to estimate the expected budget impact of maintenance treatment with Hizentra for US stakeholders. The model adopts primarily a US integrated delivery network perspective and, secondarily, a commercial perspective over a 1-year time horizon. Pharmacy costs were based on a payment mix of average sales price (73%), wholesale acquisition cost (2%), and average wholesale price (25%). Costs in the model reflect 2022 US dollars. In accordance with the International Society for Pharmacoeconomics and Outcomes Research (ISPOR) guidelines and recommendations for budget impact modeling, no discounting was performed. The PATH clinical study of Hizentra maintenance in CIDP was used to determine clinical inputs for relapse rates at initial assessment (24 weeks) and at 52 weeks for Hizentra. The ICE clinical study of Gamunex maintenance in CIDP was the basis of relapse rates for Gamunex (and other IVIGs). Literature-based estimates were obtained for infusion costs by site of care, costs of IVIG infusion-related complications, and significant IVIG AE rates. Hizentra AE rates from the US Hizentra prescribing information were assessed but were not included in the model as the AEs in CIDP were mild, easily treated, and self-limited. Sensitivity analyses and scenario analyses were conducted to evaluate variations from the base case.

RESULTS

The model showed that a Hizentra starting dose of 0.2 g/kg is expected to result in annual cost savings of US$32,447 per patient compared with IVIG. For a hypothetical 25-million-member plan, the budget impact of a 10% market share shift from IVIG to Hizentra is expected to result in savings of US$2,296,235.

CONCLUSION

This analysis projects that Hizentra is likely associated with favorable economic benefit compared with IVIG in managing CIDP.

Update on therapy of chronic immune-mediated neuropathies

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

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

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

Subcutaneous immunoglobulin treatment for chronic inflammatory demyelinating polyneuropathy

Immunoglobulin G (IgG) therapy is an established long‐term treatment in chronic inflammatory demyelinating polyneuropathy (CIDP) that is commonly administered intravenously (IVIg). The subcutaneous immunoglobulin (SCIg) administration route is a safe and effective alternative option, approved by the United States Food and Drug Administration (FDA) in 2018, for maintenance treatment of adults with CIDP. Physicians and patients alike need to be aware of all their treatment options in order to make informed decisions and plan long‐term treatment strategies. In this review, we collate the evidence for SCIg in CIDP from all published studies and discuss their implications and translation to clinical practice. We also provide guidance on the practicalities of how and when to transition patients from IVIg to SCIg and ongoing patient support. Evidence suggests that IVIg and SCIg have comparable long‐term efficacy in CIDP. However, SCIg can provide additional benefits for some patients, including no requirement for venous access or premedication, and reduced frequency of systemic adverse events. Local‐site reactions are more common with SCIg than IVIg, but these are mostly well‐tolerated and abate with subsequent infusions. Data suggest that many patients prefer SCIg following transition from IVIg. SCIg preference may be a result of the independence and flexibility associated with self‐infusion, whereas IVIg preference may be a result of familiarity and reliance on a healthcare professional for infusions. In practice, individualizing maintenance dosing based on disease behavior and determining the minimally effective IgG dose for individuals are key considerations irrespective of the administration route chosen.

Long-term treatment with subcutaneous immunoglobulin in multifocal motor neuropathy

Multifocal motor neuropathy (MMN) is a rare disease with a prevalence of less than 1 per 100,000 people. Intravenous immunoglobulin (IVIG) therapy, performed for a long-term period, has been demonstrated able to improve the clinical picture of MMN patients, ameliorating motor symptoms and/or preventing disease progression. Treatment with subcutaneous immunoglobulin (SCIg) has been shown to be as effective as IVIG. However, previously published data showed that follow-up of MMN patients in treatment with SCIg lasted no more than 56 months. We report herein the results of a long-term SCIg treatment follow up (up to 96 months) in a group of 8 MMN patients (6 M; 2F), previously stabilized with IVIG therapy. Clinical follow-up included the administration of Medical Research Council (MRC) sum-score, the Overall Neuropathy Limitation Scale (ONLS) and the Life Quality Index questionnaire (LQI) at baseline and then every 6 months. Once converted to SCIg, patients’ responsiveness was quite good. Strength and motor functions remained stable or even improved during this long-term follow-up with benefits on walking capability, resistance to physical efforts and ability in hand fine movements.

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

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

Subcutaneous immunoglobulin dose titration to clinical response in inflammatory neuropathy

INTRODUCTION

Individualized dosing is an established approach in intravenous immunoglobulin (IVIg) treatment for inflammatory neuropathies. There is less experience in effective dosing strategies for subcutaneous (SC) immunoglobulin.

METHODS

We conducted a retrospective cohort study of patients with inflammatory neuropathies transferring from IVIg to SCIg in two UK peripheral nerve services. I-RODS and grip strength were used to measure outcome. Dose and clinical progress were documented at 1 year and at last review.

RESULTS

44/56 patients remained on maintenance SCIg beyond 1 year (mean 3.3 years, range 1-9 years) with stable clinical outcomes. Clinical deteriorations were corrected by small increases in SCIg dose in 20 patients at 1 year, a further 9 requiring subsequent further up-titrations. Sixteen tolerated dose reduction. Mean dose change was + 2.4% from baseline. Two patients required IVIg bolus rescue (2 g/kg). Three patients successfully discontinued Ig therapy. Nine patients returned to IVIg due to clinical relapse or patient preference. Overall tolerance was good.

DISCUSSION

Dose titration to clinical response is an effective approach in SCIg maintenance therapy.

Quality of life in chronic inflammatory demyelinating polyneuropathy patients treated with subcutaneous immunoglobulin

BACKGROUND

Subcutaneous immunoglobulin (SCIG) is effective treatment of chronic inflammatory demyelinating polyneuropathy (CIDP). Quality of life (QoL) increases following switch from intravenous administration to SCIG, but its correlation with clinical functioning is sparsely studied.

AIMS OF THE STUDY

The aim of this study is to evaluate the correlation between QoL and clinical functioning in CIDP patients treated with SCIG.

METHODS

Danish patients with CIDP with a disease duration <10 years and currently treated with SCIG were eligible for inclusion. QoL was assessed with EQ-5D-5L and disability by the Overall Disability Sum Score (ODSS) and Rasch-built Overall Disability Scale (RODS). Gait performance was evaluated by a 40-meter-walk test (40-MWT) and a 6-spot-step test (6-SST) along with assessment of muscle strength (Medical Research Council score [MRC]). Correlations between QoL and the measured scores were calculated.

RESULTS

Of 92 eligible patients, 44 were included. QoL on the visual analogue scale (VAS) was 65% (range: 15-90) of the level of healthy controls (P = .03) and correlated to impaired gait function by 40-MWT and 6-SST. QoL correlated to RODS and ODSS, whereas there was no correlation with the MRC score.

CONCLUSIONS

In SCIG treated CIDP patients QoL is reduced and correlates to gait performance and disability.

Manual push technique, an alternative route of subcutaneous immunoglobulin administration in chronic inflammatory demyelinating polyradiculoneuropathy: A proof-of-concept study

OBJECTIVE

Subcutaneous immunoglobulin (SCIg) administered through infusion pump has been reported as effective in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) patients. In this study we evaluate an alternative technique of SCIg administration, based on the delivery of lower volumes administered daily using manual push technique (MPT) in 10 CIDP patients.

METHODS

In this randomized, controlled, two-arm, crossover clinical trial, CIDP patients were randomly assigned 1:1 to receive SCIg either by MPT or pumps for 4 consecutive months with crossover to the other. The primary objective was to assess whether MPT had the same effectiveness as pumps. The secondary objectives were to assess whether MPT resulted in greater plasma IgG levels and improved quality of life (QoL).

RESULTS

Ten patients (mean age = 48.3) were enrolled. No significant changes were observed in the efficacy parameters (INCAT, MRC, R-ODS, and GS scales). A positive mean variation of 5.4 % in plasma IgG levels in the group treated with MPT was observed at the end of MPT periods. Treatment interference, which is one of the dimensions of the Life Quality Index, showed a significant improvement in the MPT periods.

CONCLUSION

In CIDP patients, the MPT technique was as effective as pump infusion, allowed comparable, slightly increases plasma IgG levels, and also improved the QoL.

Long-term treatment with subcutaneous immunoglobulin in patients with chronic inflammatory demyelinating polyradiculoneuropathy: a follow-up period up to 7 years

Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) is a rare and heterogeneous acquired sensory-motor polyneuropathy with autoimmune pathogenesis. Intravenous immunoglobulins (IVIG) are a well-established therapy for CIDP: it is well known that at least two-thirds of these patients need these infusions for several years. More recently, Subcutaneous Immunoglobulins (SCIg) have been proved to be effective: this finding has been confirmed either in isolated cases or in few randomized trials. However, it appeared that the longest SCIg treatment follow up lasted no longer than 48 months. We report herein the results of a long-term SCIg treatment with a follow up period up to 7 years (84 months), considering safety, tolerability and patients’ perception of SCIg treatment in a CIDP population. We studied 17 patients (10 M; 7 F) with a diagnosis of CIDP, defined according to the EFNS/PNS criteria, successfully treated with IVIG every 4/6 weeks before being switched to SCIg treatment. Clinical follow-up included, apart from a routinely clinical assessment, the administration of Medical Research Council (MRC) sum-score, the Overall Neuropathy Limitation Scale (ONLS) and the Life Quality Index questionnaire (LQI). The results showed that, in the majority of this pre-selected group of CIDP patients (16/17), SCIg were well tolerated and were preferred over IVIG. Strength and motor functions remained stable or even improved during the long term follow-up (up to 84 months) with benefits on walking capability and resistance, manual activity performances and fatigue reduction.

Sustained response to subcutaneous immunoglobulins in chronic ataxic neuropathy with anti-disialosyl IgM antibodies (CANDA): report of two cases and review of the literature

INTRODUCTION

Chronic ataxic neuropathy with anti-disialosyl IgM antibodies (CANDA) is a rare disorder for which the pathological, neurophysiological, and therapeutic evidence remains anecdotal and controversial.

METHODS

This report on CANDA focuses on the neurophysiological patterns and treatment responses shared by two cases. One patient underwent nerve ultrasound follow-up. A comprehensive review of the literature highlighted the diverse experiences with different treatment options.

RESULTS

Response to different therapies was similar in both patients: intravenous immunoglobulins achieved a favorable response albeit with significant wearing-off fluctuations; treatment with subcutaneous immunoglobulins (SCIg) was an effective alternative leading to a clinical response for at least 2 years. Rituximab, which was trialed in both patients, was not continued long enough to determine its efficacy in modifying the disease course and/or modulating responsiveness to immunoglobulins. Steroids caused clinical worsening in both patients.

CONCLUSIONS

Immunoglobulin therapy appeared as the most effective in the treatment of these two patients. SCIg provided an effective treatment option for the long-term management of CANDA.

Management challenges for chronic dysimmune neuropathies during the COVID-19 pandemic

Since March 2020, the COVID-19 pandemic has led to the need to re-think the delivery of services to patients with chronic dysimmune neuropathies. Telephone/video consultations have become widespread but have compounded concerns about objective evaluation. Therapeutic decisions need, more than ever before, to be considered in the best interests of both patients, and society, while not denying function-preserving/restoring treatment. Immunoglobulin therapy and plasma exchange, for those treated outside of the home, expose patients to the hazards of hospital or outpatient infusion centers. Steroid therapy initiation and continuation pose increased infectious risk. Immunosuppressant therapy similarly becomes highly problematic, with the risks of treatment continuation enhanced by uncertainties regarding duration of the pandemic. The required processes necessitate considerable time and effort especially as resources and staff are re-deployed to face the pandemic, but are essential for protecting this group of patients and as an integral part of wider public health actions.

Long-term safety and efficacy of subcutaneous immunoglobulin IgPro20 in CIDP: PATH extension study

Objective

To investigate the long-term safety and efficacy of weekly subcutaneous IgPro20 (Hizentra, CSL Behring) in chronic inflammatory demyelinating polyneuropathy (CIDP).

Methods

In a 48-week open-label prospective extension study to the PATH study, patients were initially started on 0.2 g/kg or on 0.4 g/kg weekly and-if clinically stable-switched to 0.2 g/kg weekly after 24 weeks. Upon CIDP relapse on the 0.2 g/kg dose, 0.4 g/kg was (re)initiated. CIDP relapse was defined as a deterioration by at least 1 point in the total adjusted Inflammatory Neuropathy Cause and Treatment score.

Results

Eighty-two patients were enrolled. Sixty-two patients initially received 0.4 g/kg, 20 patients 0.2 g/kg weekly. Seventy-two received both doses during the study. Sixty-six patients (81%) completed the 48-week study duration. Overall relapse rates were 10% in 0.4 g/kg-treated patients and 48% in 0.2 g/kg-treated patients. After dose reduction from 0.4 to 0.2 g/kg, 51% (27/53) of patients relapsed, of whom 92% (24 of 26) improved after reinitiation of the 0.4 g/kg dose. Two-thirds of patients (19/28) who completed the PATH study without relapse remained relapse-free on the 0.2 g/kg dose after dose reduction in the extension study. Sixty-two patients had adverse events (AEs) (76%), of which most were mild or moderate with no related serious AEs.

Conclusions

Subcutaneous treatment with IgPro20 provided long-term benefit at both 0.4 and 0.2 g/kg weekly doses with lower relapse rates on the higher dose. Long-term dosing should be individualized to find the most appropriate dose in a given patient.

Classification of evidence

This study provides Class IV evidence that for patients with CIDP, long-term treatment with SCIG beyond 24 weeks is safe and efficacious.

Retrospective correlation analysis of plasma Immunoglobulin G and clinical performance in CIDP

Background

Chronic inflammatory demyelinating polyneuropathy (CIDP) can be successfully treated with immunoglobulin either intravenously (IVIG) or subcutaneously (SCIG). Measurement of plasma immunoglobulin G levels (P-IgG) and its correlation to clinical improvement has shown conflicting results. This study aims to clarify whether changes in P-IgG are related to clinical development in patients with CIDP treated with IVIG or SCIG.

Methods

Patients from five previous studies treated with either IVIG or SCIG with evaluation at baseline and re-evaluation after two or 10/12 weeks, respectively were included. At evaluation and re-evaluation, the following tests were done: combined isokinetic muscle strength (cIKS), grip strength, 9-hole-peg test (9-HPT), 40-meter-walk test (40-MWT), clinical examination of muscle strength score by the Medical Research Council (MRC) and measurement of plasma immunoglobulin G (P-IgG).

Results

Fifty-five patients were included in the IVIG group and 41 in the SCIG group. There was no correlation between the changes in P-IgG and cIKS in neither the IVIG group (r = 0.137, p = 0.32) nor the SCIG group (r =  − 0.048, p = 0.77). Similarly, no correlations could be demonstrated between P-IgG and grip strength, 9-HPT, 40-MWT or MRC.

Conclusions

In patients with CIDP receiving SCIG or IVIG, changes in P-IgG during treatment did not correlate with changes in muscle strength or other motor performance skills.

Immune-mediated neuropathies

Since the discovery of an acute monophasic paralysis, later coined Guillain-Barré syndrome, almost 100 years ago, and the discovery of chronic, steroid-responsive polyneuropathy 50 years ago, the spectrum of immune-mediated polyneuropathies has broadened, with various subtypes continuing to be identified, including chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and multifocal motor neuropathy (MMN). In general, these disorders are speculated to be caused by autoimmunity to proteins located at the node of Ranvier or components of myelin of peripheral nerves, although disease-associated autoantibodies have not been identified for all disorders. Owing to the numerous subtypes of the immune-mediated neuropathies, making the right diagnosis in daily clinical practice is complicated. Moreover, treating these disorders, particularly their chronic variants, such as CIDP and MMN, poses a challenge. In general, management of these disorders includes immunotherapies, such as corticosteroids, intravenous immunoglobulin or plasma exchange. Improvements in clinical criteria and the emergence of more disease-specific immunotherapies should broaden the therapeutic options for these disabling diseases.

IgPro20, the Polyneuropathy and Treatment with Hizentra® study (PATH), and the treatment of chronic inflammatory demyelinating polyradiculoneuropathy with subcutaneous IgG

Subcutaneous IgG (SCIG) administration may be preferred over the intravenous route (IVIG) in chronic inflammatory demyelinating polyneuropathy (CIDP) because it minimizes ‘end of cycle’ treatment-related fluctuations, reduces systemic adverse effects, improves convenience/quality of life and potentially lowers overall costs. Early reports of the use of highly concentrated SCIG preparations suggested they were effective and well-tolerated in chronic inflammatory demyelinating polyneuropathy. This was confirmed in the Polyneuropathy and Treatment with Hizentra® study of 172 subjects randomized to receive maintenance therapy with placebo or one of two doses of IgPro20 (20% IgG stabilized with L-Proline) for 6 months. Risk of relapse was reduced by SCIG in a dose-related manner as compared with placebo. A total of 88% of polyneuropathy and treatment with hizentra subjects felt the subcutaneous method was ‘easy to learn’. Local adverse events were mostly mild or moderate, and systemic adverse events were infrequent. Some patients may prefer maintenance therapy with SCIG over IVIG.

Intravenous immunoglobulin treatment in chronic inflammatory demyelinating polyradiculoneuropathy, a time to start and a time to stop

Intravenous immunoglobulin (IVIg) is often used as preferred treatment in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). Several studies highlighted the short-term efficacy of IVIg for CIDP yet many patients need maintenance therapy. Notwithstanding the fact IVIg has been used for over 30 years in CIDP, there is only limited evidence to guide dosage and interval during maintenance treatment. The variation in disease course, lack of biomarkers, and fear of deterioration after stopping IVIg makes long-term treatment challenging. Recent studies suggest a proportion of patients receive unnecessary IVIg maintenance treatment. This review provides an overview of the use of IVIg for CIDP treatment, focusing on evidence for long-term IVIg use.

Subcutaneous "bolus" immunoglobulin dose in CIDP: A proof-of concept study

BACKGROUND

Subcutaneous (SC) immunoglobulin (Ig) is an effective therapy for Chronic Inflammatory Demyelinating Polyradiculoneuropathy (CIDP). However, optimal dosage and frequency of administration remain to be clarified.

OBJECTIVES

We sought to assess the feasibility and tolerability of a novel regimen of SCIg administration, based on concentrated "bolus" doses delivered every other week, as compared to the "conventional" SCIg regimen, based on 1-3 administrations/week.

MATERIALS AND METHODS

Consecutively consenting CIDP patients (6 men and 1 woman) were crossed-over from SCIg "conventional" to SCIg "bolus" and followed-up for 6months. The main endpoints were: tolerability, defined as the percentage of patients successfully completing the study, patient's perceived disability, as measured by the Rasch-built Overall Disability Scale (R-ODS), life quality index (LQI), and inflammatory neuropathy cause and treatment (INCAT) scale.

RESULTS

SCIg "bolus" was well tolerated by all patients. The R-ODS score significantly improved (p=0.042), as well as the LQI sub-domains related to the interference of treatment in daily living activities (p=0.026), and therapy-related problems (p=0.039). No significant change was observed in the INCAT (p=0.317) score. There were no cases of drop-out and/or dose adjustment during follow-up.

CONCLUSIONS

SCIg "bolus" seems to represent an effective and well-tolerated option for CIDP maintenance therapy.

Subcutaneous immunoglobulin as first-line therapy in treatment-naive patients with chronic inflammatory demyelinating polyneuropathy: randomized controlled trial study

BACKGROUND AND PURPOSE

Subcutaneous immunoglobulin (SCIG) is effective as maintenance treatment in chronic inflammatory demyelinating polyneuropathy (CIDP). We investigated whether multiple subcutaneous infusions are as effective as conventional therapy with intravenous loading doses in treatment-naive patients with CIDP.

METHODS

Twenty patients fulfilling the clinical and electrophysiological criteria for CIDP were included and treated with either SCIG (0.4 g/kg/week) for 5 weeks or intravenous immunoglobulin (IVIG) (0.4 g/kg/day) for 5 days. After 10 weeks, patients were switched to the opposite treatment arm and followed for a further 10 weeks. All participants were evaluated at weeks 0, 2, 5 and 10 during both therapies. Primary outcome was combined isokinetic muscle strength (cIKS). Secondary outcomes were disability, clinical evaluation of muscle strength and the performance of various function tests.

RESULTS

All participants received both therapies, 14 completing the protocol. Overall, cIKS increased by 7.4 ± 14.5% (P = 0.0003) during SCIG and by 6.9 ± 16.8% (P = 0.002) during IVIG, the effect being similar (P = 0.80). Improvement of cIKS peaked 2 weeks after IVIG and 5 weeks after SCIG. Disability improved during SCIG treatment only. Muscle strength determined by manual muscle testing improved after 5 and 10 weeks during SCIG but only after 5 weeks during IVIG. The remaining parameters improved equally during both treatments. Plasma immunoglobulin G levels at baseline and improvement of cIKS were related.

CONCLUSION

In treatment-naive patients with CIDP, short-lasting SCIG and IVIG therapy improve motor performance to a similar degree, but with earlier maximal improvement following IVIG than SCIG treatment.

Subcutaneous immunoglobulin for maintenance treatment in chronic inflammatory demyelinating polyneuropathy (The PATH Study): study protocol for a randomized controlled trial

BACKGROUND

Subcutaneous administration of Ig (SCIg) has gained popularity as an alternative route of administration but has never been rigorously examined in chronic inflammatory demyelinating polyneuropathy (CIDP).

METHODS/DESIGN

The primary objective of the PATH study (Polyneuropathy and Treatment with Hizentra) is to determine the efficacy of two different doses of SCIg IgPro20 (0.2 g/kg bw or 0.4 g/kg bw) in a 24-week maintenance treatment of CIDP in comparison to placebo. The primary efficacy endpoint will be the proportion of patients who show CIDP relapse (1-point deterioration on the adjusted Inflammatory Neuropathy Cause and Treatment (INCAT) disability score) or are withdrawn within 24 weeks after randomization for any reason. IVIg-dependent adult patients with definite or probable CIDP according to the European Federation of Neurological Societies/Peripheral Nerve Society who fulfil the inclusion and exclusion criteria will be eligible. Based on sample-size calculation and relapse assumptions in the three arms, a sample size of 58 is needed per arm (overall sample size will be 350, of which 174 will be randomized). All eligible patients will progress through three study periods: an IgG dependency period (≤12 weeks) to select those who are Ig dependent; an IVIg restabilization period (10 or 13 weeks), which will be performed using the 10 % IgPro10 product; and an SC treatment period (24 weeks, followed by a 1-week completion visit after last follow-up). Patients showing IVIg restabilization will be randomized to demonstrate the efficacy of SCIg IgPro20 maintenance treatment over placebo. After completing the study, subjects are eligible to enter a long-term, open-label, extension study of 1 year or return to their previous treatment. In case of CIDP relapse during the 24-week SC treatment period, IgPro10 rescue medication will be offered. Safety, tolerability, and patients' preference of Ig administration route will be examined.

DISCUSSION

The PATH trial, which started in March 2012, is expected to finish at the end of 2016. The results will increase knowledge about the efficacy, safety, and tolerability of SCIg in maintenance management of CIDP patients.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT01545076 . Registered on 1 March 2012.