To evaluate long-term safety and efficacy of facilitated subcutaneous immunoglobulin (fSCIG; human immunoglobulin G [IgG] 10% with recombinant human hyaluronidase) in patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP).

fSCIG is under investigation as a maintenance therapy for patients with CIDP.

ADVANCE-CIDP 3 (NCT02955355) is a long-term extension of ADVANCE-CIDP 1 (NCT02549170), a Phase 3, double-blind, randomized, placebo-controlled study that evaluated efficacy and safety/tolerability of fSCIG as maintenance therapy for CIDP. Patients completing 6 months without relapse in ADVANCE-CIDP 1 could enter ADVANCE-CIDP 3 and receive open-label fSCIG treatment. The primary outcome is safety. Efficacy is an exploratory outcome including evaluation of CIDP relapse.

This interim analysis included 79 patients (mean age 53.9 years, 54.4% male) with total follow-up of 169 patient-years; 2595 infusions were administered. Median exposure was 23 months (range: 0–61 months). Most adverse events (AEs) were mild or moderate, local and self-limiting, and consistent with the established fSCIG safety profile. Overall, 1166 AEs (40 severe; 18 serious) occurred in 70 patients (88.6%). Of these, 661 AEs (19 severe; 2 serious) were related to fSCIG. Systemic AEs (e.g. hemodynamic alterations) were infrequent. Overall, 5 patients relapsed; the 6-month relapse rate was 1.5%.

ADVANCE-CIDP 3 demonstrates favorable long-term safety and tolerability of fSCIG, and a low relapse rate, supporting its use as a maintenance treatment for CIDP.