Subcutaneous Immunoglobulins are a Valuable Treatment Option in Myasthenia Gravis

Usefulness of subcutaneous immunoglobulin therapy in the management of myasthenia gravis: a retrospective cohort study

Introduction

To describe the efficacy of subcutaneous immunoglobulin (SCIg) in patients with myasthenia gravis (MG).

Methods

This was a retrospective study conducted in the neuromuscular referral center of Bordeaux (between January 1, 2014 and March 31, 2021) with MG patients treated with SCIg. The main outcome was SCIg efficacy assessed by the before and after SCIg Myasthenia Gravis Foundation of America (MGFA) clinical classification, the duration of hospitalization and the number of days of orotracheal intubation (OTI).

Results

Sixteen patients were included in the study (11 females; 5 males). Nine patients were still treated with SCIg at the end of the study (March 31, 2021) and then underwent prospective follow-up. The average age of the patients was 56.1 (19–83) years. The median duration of MG at onset of SCIg was 37.4 months. Eight patients (50%) remained stable (4 in stage MGFA-IV and 4 in MGFA-III). Eight patients (50%) improved: 3 from MGFA-IV to MGFA-III, 1 from MGFA-IV to MGFA-II, 1 from MGFA-IV to MGFA-I, 2 from MGFA-III to MGFA-II and 1 from MGFA-III to MGFA-I (no patient worsened). The duration of disease progression did not appear to affect the response to SCIg therapy. The number of hospital days per month was significantly reduced after SCIg compared to before, and the number of days in intensive care unit and the number of days of OTI were also reduced. Only minor adverse effects were noted, and 80% of patients were in favor of continuing SCIg.

Conclusions

SCIg is a well-tolerated and useful treatment in MG, offering interesting perspectives in the management of MG patients. However, further large-scale prospective studies are needed to confirm these results.

Maintenance treatment with subcutaneous immunoglobulins in the long-term management of anti-HMCGR myopathy

We describe the clinical response to long-term subcutaneous immunoglobulins (SCIg) in anti-3‑hydroxy-3-methyl-glutaryl-coenzyme-A-reductase (anti-HMCGR) myopathy previously treated with intravenous immunoglobulins (IVIg). We collected data from patients affected by anti-HMGCR myopathy, switched from IVIg to SCIg therapy, after achieving clinical stabilization. The Medical Research Council sum score, creatine kinase (CK) levels, and anti-HMGCR antibodies were used to assess the response. We identified three patients with anti-HMGCR myopathy treated with SCIg with a favourable clinical course, allowing the maintenance of clinical stability, the reduction or suspension of steroids therapy and in two of them a complete CK normalization. Finally, anti-HMGCR antibodies tested in all patients after 12 months from SCIg starting, showed a global decrease. SCIg represent an useful alternative to long-term IVIg as already well known in several autoimmune neuromuscular disorders and inflammatory myopathies with advantages of lower side effects and home self-administration.

Pharmacodynamic Properties of Subcutaneous Immunoglobulin in Myasthenia Gravis: Sub-analyses From an Open-Label Trial

Background: We previously reported an open-label prospective trial of subcutaneous immunoglobulin (SCIg) in mild to moderate exacerbations of myasthenia gravis (MG). The effective dose of SCIg in MG and whether measured immunoglobulin G (IgG) levels correlated with measures of disease burden were not reported.

Objectives: To understand the relationship between SCIg dosing and serum IgG levels on measures of disease burden: quantitative MG (QMG), MG activities of daily living (MG-ADL), MG composite (MGC), and manual muscle testing (MMT) scores.

Methods: We performed post-hoc analyses of variance to assess change in oculobulbar and generalized sub-scores. We assessed the improvement in QMG, MG-ADL, MGC, or MMT over intervals from baseline to week 2, weeks 2–4, and week 4 to end of study. Improvement was either greater than (coded 1) or was equal to or less than (coded 0) the previous 2 weeks. Binaries were assessed in binary logistic regression as a function of SCIg dose over the two-week interval as the independent variable. We also performed linear regression analyses with change in the clinical scores as the dependent variable and change in IgG level over the entire study period and over the interval from weeks 2 to 4, during which change in IgG level was maximal, as the independent variables.

Results: Subanalysis of QMG and MG-ADL scores demonstrated significant reductions in the oculobulbar and the generalized portions of both measures. Binary logistic regression analyses did not find any statistically significant correlations between the odds of improvement and weight-adjusted dose of SCIg over 2-week intervals. There were no significant relationships between changes in scores and IgG level over the entire study period or over the interval from weeks 2 to 4.

Conclusions: Although SCIg dose varied over the study period, the odds of improvement were not significantly correlated with this, which suggests that the current dose of 2 g/kg for SCIg should be compared to different, possibly lower, dosing regimens head-to-head. The change in clinical scores was not significantly associated with IgG levels suggesting a complex relationship. SCIg may be effective for both ocular and generalized presentations of MG.

Subcutaneous Immunoglobulin Therapy for Chronic Inflammatory Demyelinating Polyneuropathy: A Nursing Perspective

Chronic inflammatory demyelinating polyneuropathy (CIDP), an immune-mediated peripheral neuropathy, is frequently treated with long-term maintenance intravenous immunoglobulin (IVIG). However, disadvantages of IVIG are the systemic adverse reactions, lengthy infusions, and need for vascular access. Subcutaneous immunoglobulin (SCIG) addresses many of the issues encountered by those unable, or unwilling, to tolerate the treatment burden of long-term IVIG. Subcutaneous immunoglobulin, a 20% solution stabilized with L-proline, is US Food and Drug Administration-approved for CIDP maintenance therapy in patients after being stabilized with IVIG. Approval was based on a randomized, double-blind, placebo-controlled trial where SCIG demonstrated superiority over placebo and was safe and efficacious in maintaining function. In addition to reviewing the primary efficacy results from the clinical trial, this article aims to update the neurology nursing community on a new option for long-term management of CIDP, including the practicalities of initiating and maintaining patients on SCIG therapy.

Current pharmacotherapeutic options for myasthenia gravis

Introduction: Novel options for immune-based therapy in myasthenia gravis are improving the therapeutic outlook for patients. Multiple clinical trials on immunomodulation, complement inhibitors, and FcR inhibitors are providing evidence for novel immune-based therapies that promise to improve outcomes in myasthenia patients. These more focused immune treatments are reviewed in this paper.Areas covered: This paper outlines classical treatment for myasthenia gravis and then reviews recent clinical trial evidence for novel immune therapies, particularly complement inhibitors and FcR inhibitors. Further, as immune therapies expand in other areas of medicine, such as oncology, iatrogenic myasthenia is being observed as a complication of some novel treatments.Expert opinion: Exciting new options to help patients with myasthenia gravis are now available or in phase 3 trials based on promising phase 2 results. Manipulation of the immune system can also lead to iatrogenic MG. Although novel treatments can improve care for myasthenia gravis patients, future developments that prevent the production of specific abnormal auto-antibodies are desirable.