Baxter International, a healthcare company based in Deerfield, Ill., has released results from its phase III clinical trial evaluating Gammagard Liquid 10% (Immune Globulin Infusion (Human)) for the treatment of multifocal motor neuropathy (MMN).

The phase III, randomized, double-blind, placebo-controlled, cross-over, multi-center study evaluated whether Gammagard Liquid was superior to placebo in preserving muscle grip strength and preventing progression of disability in 44 patients with MMN. Patients completed five study phases, each 12 weeks long—three open-label phases with Gammagard Liquid and two double-blind, cross-over treatment phases with Gammagard Liquid or placebo—with an average monthly dose of 1.2 g/kg of body weight. This is the largest randomized clinical trial of patients with MMN to date. MMN is associated with a progressive, asymmetric limb weakness most often affecting the upper limbs, which can lead to significant difficulty with simple manual tasks.

Gammagard Liquid met its two primary efficacy endpoints, demonstrating a 3.75% increase in mean grip strength of the more affected hand during treatment, as compared to a 31.38% decrease in mean grip strength with placebo administration. The study also found that a greater proportion of patients who received placebo experienced progressive disability, as assessed by the Guy's Neurological Disability Score compared to those receiving Gammagard Liquid (35.7% versus 11.9%, respectively). 

If study participants experienced intolerable interference with daily activities, the study allowed them to switch from placebo to Gammagard Liquid. The majority of patients on placebo (69%) required an accelerated switch before 12 weeks, with some in as few as seven days. 

"If approved by the regulatory authorities, Gammagard Liquid will become the first immunoglobulin treatment available for patients with MMN in the United States," said Hartmut J. Ehrlich, M.D., vice president of global research and development in Baxter's BioScience business.

No deaths or unexpected serious adverse events related to study product occurred. The most commonly reported adverse reactions (reported in five or fewer percent of subjects) were headache and muscular weakness. The proportion of infusions associated with headache was 2.1% with Gammagard Liquid and 2.3% with placebo. The proportion of infusions associated with muscular weakness was 0.4% with Gammagard Liquid and 0.8% with placebo.