Subcutaneous vs. intravenous immunoglobulin in CIDP: pharmacokinetic and clinical response

Impact of subcutaneous immunoglobulin on quality of life in patients with chronic inflammatory demyelinating polyneuropathy previously treated with intravenous immunoglobulin

INTRODUCTION/AIMS

Intravenous immunoglobulin (IVIg) is a common therapy for patients with chronic inflammatory demyelinating polyneuropathy (CIDP). IVIg may cause systemic adverse events (AEs); therefore, infusion of subcutaneous immunoglobulin (SCIg) may be preferred by some patients. In this study we document the experiences of patients transitioning from IVIg to SCIg.

METHODS

Transitioning subjects with CIDP were followed in a 6-month prospective, open-label study. The primary endpoint was percentage of subjects who withdrew for any reason (including significant AEs). The secondary endpoint was symptom progression or relapse requiring a change in management. Quality of life (QOL) and treatment satisfaction were assessed using the Short Form 36-item Health Survey (SF-36), Treatment Satisfaction Questionnaire for Medication (TSQM), and Chronic Acquired Polyneuropathy Patient-Reported Index (CAP-PRI). Efficacy was assessed using the Inflammatory Rasch-built Overall Disability Scale, hand-held dynamometry, limb motor strength testing (LMST), and timed 25-ft walk (T25-FW).

RESULTS

Fifteen CIDP subjects transitioned from IVIg to SCIg. Of these, three (20%) met the primary endpoint and one (7%) met the secondary endpoint. The SF-36 showed a statistically significant improvement for the domain of role limitations-physical after 24 weeks (P = .03), with no significant differences observed in other domains. TSQM and CAP-PRI showed significant differences in favor of SCIg (P = .003 and .02, respectively). No significant differences were observed in efficacy after 24 weeks, except for LMST, which favored SCIg (P = .003). Eight of the 12 study completers (67%) continued with SCIg.

DISCUSSION

Transition to SCIg was associated with maintained efficacy and improved QOL.

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.

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.

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.

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.

Pharmacokinetics and Pharmacodynamics of Intravenous Immunoglobulin G Maintenance Therapy in Chronic Immune-mediated Neuropathies

The regimen for IVIg maintenance treatment varies considerably between patients with chronic immune-mediated neuropathies. Although it is widely recognized that treatment regimens should be improved, detailed pharmacokinetics (PK) of IVIg have not yet been established. We aimed to determine the PK of IVIg maintenance treatment in patients with clinically stable, treatment-dependent, chronic immune-mediated neuropathy. Patients received a median IVIg dose of 30 g (range, 15-70 g) every 14 days (range, 7-28 days) resulting in high IgG peak levels (median, 25.9 g/L; range, 16.7-41.0 g/L) and trough levels (median, 16.1 g/L; range, 9.7-23.6 g/L). IgG PK parameters, including half-life (median, 23.1 days; range, 11-60 days), were constant during subsequent courses in the same patients, but varied considerably between patients. The IgG levels at 1 week after infusion correlated with grip strength. These results provide insight into the PK of IVIg maintenance treatment in patients with chronic immune-mediated neuropathies.