In an MDA-supported worldwide study, researchers found that surgical removal of an organ called the thymus reduced muscle weakness and lowered the need for drugs that suppress the immune system in people with myasthenia gravis (MG).

MG is an autoimmune neuromuscular disease that causes varying degrees of muscle weakness and fatigue. Initial treatment typically involves drugs, called acetylcholinesterase inhibitors, that elevate levels of a neurotransmitter called acetylcholine responsible for transmitting signals from nerves to muscle. If these drugs prove ineffective, patients are treated with immunosuppressive drugs, including corticosteroids.

“Although the first report of thymectomy (surgery to remove the thymus) in myasthenia gravis patients was 75 years ago, it has been unclear whether or not removal of the thymus is associated with clinical improvement or remission,” said MDA Scientific Program Officer Amanda Haidet-Phillips. “The results from this large, well-controlled study demonstrate the benefits of surgery as a treatment option for many with MG.”

In the trial, which was conducted in 67 centers across 18 countries, 126 participants between the ages of 18 and 65 years were treated either with surgery and prednisone (an immunosuppressant steroid) or with prednisone alone. Of the 126 participants, 57 had a thymectomy.

On average trial investigators found that the combination of surgery and prednisone treatment reduced overall muscle weakness more than the prednisone-only treatment. After 36 months of prednisone treatment, both groups of patients had better QMG scores, a measure of muscle strength.

The researchers also found that, when compared with participants who were treated only with prednisone, participants who had surgery:

• required lower daily doses of prednisone to control the disease;
• had less need for additional immunosuppressant drugs; and
• experienced fewer adverse events (such as hospitalization).

“Surgery involves risk and can be an expensive treatment option,” Haidet-Phillips noted. “Thus, having evidence to support the benefits of surgery as a therapy is essential.

“The results from this trial will help to inform clinicians and patients about the potential benefits of surgery for MG and lead to improvements in care for people with the disease.”

When considering any treatment option, it’s recommended that you always consult with your doctor or your MDA Care Center team.

MDA supported this work through a grant to Gil Wolfe, lead investigator for the study and Professor and Irvin and Rosemary Smith Chair of Neurology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, New York. The project represents a collaborative effort between MDA, the National Institute of Neurological Disorders and Stroke (part of the U.S. National Institutes of Health) and the Myasthenia Gravis Foundation of America.