Switch from Intravenous to Subcutaneous Immunoglobulin in CIDP and MMN : 12 Months Results from an Observational Study

Introduction

Since 2018 subcutaneous immunoglobulin (SCIg) has been approved for the maintenance treatment of chronic inflammatory demyelinating polyneuropathy (CIDP). However, comprehensive real-world data for long-term SCIg treatment are scarce for CIDP and especially for other immune-mediated neuropathies such as multifocal motor neuropathy (MMN).

Methods

In this observational study, 62 patients with CIDP and 13 with MMN were analyzed. Patients had been receiving regular intravenous immunoglobulin (IVIg) and transitioned to an equivalent weekly dose of SCIg. A comprehensive set of biographical, clinical, and paraclinical data were compared between the time of the switch and after 12 months.

Results

Subcutaneous administration was continued by 84% of the patients with CIDP and 77% of the patients with MMN for at least 12 months. Patients were clinically and electroneurographically stable over a period of 12 months under SCIg therapy and treatment satisfaction and preference was high. Nevertheless, intensified treatment especially by increasing the SCIg dose was necessary in a relevant proportion of both groups (31% of patients with CIDP and 40% of patients with MMN). The proportion of patients with concomitant autoimmune disease was higher in patients with CIDP with intensified treatment.

Conclusions

SCIg is an effective alternative maintenance treatment for patients with CIDP and MMN who have previously responded to IVIg. Switching to an equivalent weekly dose of SCIg as a replacement for monthly IVIg is both feasible and effective in most patients. Nevertheless, about one-quarter of patients require an increased dose of subcutaneous immunoglobulin, which is well tolerated and often preferred to allow continuation of this treatment modality.