Eligible CIDP trial subjects were randomized to treatment with Gamunex (2g/kg as loading dose followed by 1g/kg every three weeks) or placebo for up to 24 weeks. The primary endpoint, response in functional disability, was observed in 54% of subjects treated with Gamunex (2g/kg loading dose, followed by 1g/kg maintenance dose every three weeks) compared to 21% on placebo when assessed up to six months in the first treatment period. Longer-term (up to one year), the probability of relapse was lower with Gamunex compared to placebo, 13% versus 45%, respectively.
The incidence of serious adverse events per infusion was low, 0.8% for Gamunex, and 0.19% for placebo. Adverse events resulting in study discontinuation totaled three trial subjects for Gamunex and two trial subjects for placebo. The most common events seen with Gamunex were headache, fever, and elevated blood pressure.