Thymectomy is better than prednisone-only treatment for myasthenia gravis

By John Murphy, MDLinx
Published August 11, 2016

Key Takeaways

Thymectomy plus prednisone is a better treatment option than prednisone alone for patients with myasthenia gravis, according to a landmark 3-year clinical investigation.

In this multi-center randomized trial, patients who underwent thymectomy had less severe disease, required less immunosuppressive therapy, and had fewer adverse effects, researchers showed in a study published August 11, 2016 in The New England Journal of Medicine.

“Our results support the idea that thymectomy is a valid treatment option for a major form of myasthenia gravis,” said lead investigator Gil Wolfe, MD, Professor and Irvin and Rosemary Smith Chair of Neurology at the Jacobs School of Medicine and Biomedical Sciences, State University of New York Buffalo, in Buffalo, NY.

Although thymectomy has been a mainstay for decades in the treatment of myasthenia gravis, no clinical trials have shown conclusive evidence of its benefit, the researchers noted.

For this study—the Thymectomy Trial in Non-Thymomatous Myasthenia Gravis Patients Receiving Prednisone Therapy (MGTX)—the investigators enrolled 126 patients (18 to 65 years old) who had mild-to-severe non-thymomatous myasthenia gravis for less than 5 years and elevated levels of acetylcholine receptor antibodies. The researchers assigned all patients to a standardized alternate-day regimen of prednisone, and randomly assigned one-half of the patients to also undergo complete trans-sternal thymectomy.

After 36 months of prednisone treatment, both groups of patients showed reduced disease severity as measured by Quantitative Myasthenia Gravis scores; however, the thymectomy patients scored 2.85 points lower than the prednisone-only patients.

Patients in the thymectomy group also required less prednisone on average (44 mg vs. 60 mg). In addition, fewer thymectomy patients than prednisone-only patients required immunosuppression with azathioprine (17% vs. 48%) or were hospitalized for exacerbations (9% vs. 37%).

“Our results suggest surgery is a legitimate option for patients to consider,” Dr. Wolfe said. “We hope that it will help doctors and patients weigh the costs and benefits of how best to reduce the disability that may impact myasthenia gravis patients on a daily basis as they go about their lives.”

The researchers acknowledged that surgery carries risks of its own and is expensive. In 2013, hospitals charged an average of $86,000 per extended transternal thymectomy, not including doctors’ fees, according to the Agency for Healthcare Quality and Research.

“We greatly appreciate the gamble patients took when they agreed to be subjects and are grateful for the help they provided in answering this 50-year old question,” said one of the study’s leaders Gary R. Cutter, MS, PhD, Professor of Biostatistics at the University of Alabama at Birmingham School of Public Health, in Birmingham, AL.

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