IVIG Treatment Benefits Those With Worsening MG

A clinical trial to test the effectiveness of intravenous immunoglobulins (IVIG) in treating myasthenia gravis (MG) has provided what the investigators say is the “first reliable evidence for the effectiveness of IVIG in patients with MG and worsening weakness.”

In MG, the immune system mistakenly attacks components of the neuromuscular (nerve-to-muscle) signal transmission system, resulting in fluctuating weakness that can be severe. It’s generally treated with drugs that prolong the action of a chemical carrier of nerve signals and/or with those that suppress the immune system.

Two other treatments, less often used, are plasmapheresis, which removes the offending immunoglobulins from the blood; and, somewhat paradoxically, immunoglobulin infusion (IVIG), which adds pooled immunoglobulins from donors. The added immunoglobulins are thought to redirect the immune system.

Lorne Zinman at Sunnybrook Health Sciences Center in Toronto and colleagues, who published their findings in the March 13 issue of Neurology, randomly assigned 51 adults with MG and worsening weakness to receive either IVIG or an infusion of an inactive solution (placebo).

Two weeks after a two-day infusion of immunoglobulins, or two days of the placebo infusion, 25 percent of the IVIG group showed improvement, compared with 6 percent of the placebo group. None of those who received IVIG worsened, while 4 percent of those on placebo did.

Functional changes were relatively small. They were the most meaningful in those with moderate to severe MG, compared to those with mild symptoms. Onset of the effect was rapid compared with the usual response to medications.

There were no serious side effects or adverse events.