Long-term follow-up of facilitated subcutaneous immunoglobulin therapy in multifocal motor neuropathy

Objective: To assess the feasibility, efficacy and patient satisfaction of long-term facilitated subcutaneous immunoglobulin therapy (fSCIG) in multifocal motor neuropathy (MMN). Methods: Twelve patients previously participating in a randomized trial investigating the short-term efficacy of fSCIG were offered to switch to fSCIG maintenance therapy following a variable interval on conventional subcutaneous immunoglobulin. Results: Eight patients were switched to fSCIG maintenance therapy, seven of whom were invited for a follow-up assessment after 18 months (range 13–23 months) of treatment. The age at follow-up was 57 years (range 45–70 years) and patients received a median weekly dose immunoglobulin G of 32.5 g (range 20.0–50.0 g), the dose being unaltered compared to baseline values following completion of the fSCIG trial. In five patients the infusion was biweekly, whereas two patients were infused weekly. The follow-up mean isometric strength normalized to pre-trial values was 107.7% (95% CI 86.4–129.0%) being non-inferior to baseline values (104.7%, 95% CI 97.6–111.8%, P = 0.015). The mean ODSS was 2.0 (95% CI 0.8–3.2) which is identical to the baseline score following completion of the fSCIG trial, the P-value for non-inferiority being <0.0001. The secondary variables of impairment, function and quality of life at follow-up all were non-inferior to baseline values (P ≤ 0.046). Conclusion: fSCIG seems feasible and effective for long-term maintenance treatment in patients with MMN.