Immune Globulin Approved for Multifocal Motor Neuropathy

Emma Hitt, PhD


June 27, 2012

June 27, 2012 — Immune Globulin Infusion (Human), 10% (Gammagard Liquid, Baxter International, Inc), has been approved by the US Food and Drug Administration (FDA) as a treatment for multifocal motor neuropathy (MMN), making it the first immunoglobulin treatment approved here for this condition.

MMN is a "challenging neuromuscular disease to diagnose and manage, and patients have had limited treatment options," noted trial investigator Said R. Beydoun, MD, professor of neurology at the Keck Medical Center, University of Southern California, in Los Angeles, in a statement from Baxter issued June 25.

Immune globulin infusion, 10%, was approved for use with MMN patients in Europe in 2011. This week's FDA approval was based on the results of a phase 3 randomized trial that evaluated the infusion in 44 adults with MMN from 17 sites. Results of the trial were presented at the American Academy of Neurology annual meeting in April this year.

The 2 co-primary endpoints were grip strength in the more affected hand, and disability as measured by Guy's Neurological Disability Scale.

A total of 41 subjects completed 5 study phases, each lasting 12 weeks, which included 3 open-label stabilization phases with immune globulin, 10%, and 2 double-blind, crossover phases with immune globulin or placebo.

Patients demonstrated a substantially greater decline from baseline (34.13%; 95% confidence interval [CI], 7.35-60.91) in mean grip strength in the more affected hand after receiving placebo vs immune globulin (P = .005).

In addition, 35.7% of patients receiving placebo showed signs of deterioration compared with only 11.9% of those receiving treatment, and 69% of patients taking placebo later switched to the immune globulin infusion owing to deterioration.

A greater proportion of subjects also had a decline of 30% or greater in grip strength in the more affected hand (42.9% vs 4.8%; P < .001), as well as in the less affected hand (31.0% vs 0%; P < .001), after placebo compared with immune globulin.

Adverse reactions observed in at least 5% of subjects during immune globulin infusion were headache, chest discomfort, muscle spasms, muscular weakness, nausea, oropharyngeal pain, and pain in extremity.

Serious treatment-related adverse reactions included pulmonary embolism and blurred vision, but no deaths were reported.

MMN is estimated to afflict 1 to 2 people in every 100,000 individuals and is associated with progressive, asymmetric limb weakness, mostly affecting the upper limbs. Most patients are between 20 and 50 years of age at onset of the disease, which has a higher incidence in men than in women.

"The regulatory approval of Gammagard Liquid for the treatment of MMN is an important milestone for Baxter as we continue to build our presence in the immunoglobulin market and expand into rare diseases in neurology," said Ludwig Hantson, PhD, president of Baxter's BioScience business, in the company's statement. "With Gammagard, we can offer patients with MMN a therapeutic option that has been well studied and used with primary immunodeficiency patients for many years."


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