Evaluate efficacy and safety of 3 different maintenance dosages of IVIG in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP).

Based on randomized clinical trials, the usual standard regimen is a 2g/kg loading dose and 1g/kg maintenance dose every 3 weeks. Dose ranging studies have not been done previously.

The ProCID study, a prospective, double-blind, randomized, parallel-group, multi-center phase III study, investigated the efficacy and safety of NewGam (Panzyga®) in patients with CIDP at the standard maintenance dose (1g/kg) and at a lower (0.5g/kg) and a higher (2g/kg) maintenance dose every 3 weeks.

The study enrolled 142 patients with definite or probable CIDP according to EFNS/PNS Criteria randomized 1:2:1 to receive either 0.5g/kg, 1g/kg or 2g/kg. The primary endpoint, the rate of responders in the 1g/kg arm, defined as a decrease of at least 1 point in the adjusted INCAT score at Week 24 compared to baseline, was 79.7% (95% CI: 68.8, 87.5) in the intention-to-treat population (55/69 patients) with the lower CI exceeding the predefined threshold of 42%, thus confirming the efficacy of 1g/kg Newgam in the maintenance treatment of CIDP. There appeared to be a dose-dependent response in the proportion of adjusted INCAT score responders with higher proportions with increasing dose: 64.7%, 79.7% and 91.7% respectively in the 0.5g, 1g and 2g/kg groups. Analyses of the secondary efficacy endpoints consistently supported the primary analysis showing a worsening during the IVIG or corticosteroid Wash-out Phase and improvements during the IVIG treatment period. Safety was as expected for IVIG.

The ProCID study confirmed the efficacy of NewGam in patients with CIDP in the 1g/kg group. The results also showed a dose response with higher proportion of responders in the 2g/kg group compared to the 1g/kg and 0.5g/kg treatment groups.