In myasthenia, surgery to remove the thymus provides benefits even years later

BUFFALO, NY – Surgery to remove the thymus in patients with myasthenia gravis (MG), a rare autoimmune disease affecting neuromuscular function, provides significant clinical benefits up to five years after the procedure, according to a report. article published in January 25 in The neurology of lancet.

The study followed 68 patients up to five years after undergoing thymectomy, surgical removal of the thymus. Among the benefits they have presented are improving disease outcomes, reducing the number of immunosuppressive drugs, and reducing the number of hospitalizations to treat exacerbations of the disease. These benefits reduce health care costs.

The article describes the results of an extension study of a subgroup of MG patients involved in MGTX, a previously published international trial that definitively confirmed the benefit of thymectomy, even at home. MG patients with no chest tumor.

No less than 60,000 Americans have been diagnosed with MG and its incidence is increasing as a result of improved diagnostic techniques and an aging population. Symptoms of MG may include droopy eyelids; blurred or double vision; difficulty speaking, swallowing and breathing and muscle weakness.

"Our current findings reinforce the benefits of thymectomy found in this original study, dispelling any doubts about the benefits of the procedure and the duration of these benefits," said Gil I. Wolfe, MD, lead author of the study. International team that conducted the current study, Irvin. and Rosemary Smith, Chair of the Department of Neurology at the Jacobs School of Medicine and Biomedical Sciences at the University of Buffalo and Chair of the UBMD Neurology. "We hope that the new findings will help reverse the apparent reluctance to do a thymectomy and that the proportion of thymectomy-affected MG patients will increase."

Wolfe was the holder of the Clinical Research Chair and the lead author of the leading MGTX trial, published in the New England Journal of Medicine in 2016, one of the longest and most important clinical trials in the world. Story of MG.

This trial, which followed patients for three years, was the first to definitively confirm the benefits of surgical removal of the thymus at the onset of the disease. The operated patients were compared to those with the state of the disease and the amount of corticosteroid prednisone they needed. Patients who had had a thymectomy needed one-third less prednisone to control their condition and also had better results.

The researchers conducted the present study to determine how long after surgery the benefits could be sustained.

"In previous retrospective studies, there was skepticism about the impact of thymectomy over more than three or four years," Wolfe said. "The hypothesis was that after that, the improvement rates would be the same between patients who had undergone a thymectomy and those who did not have one."

The new findings, based on the clinical status of patients, drug requirements and adverse events, proved this incorrect badumption. The researchers found that the benefits of thymectomy continued to be observed up to five years after the procedure and that improvements continued to exceed those seen with medical treatment alone.

Operated patients who continued to take prednisone were able to take significantly lower doses of steroids than non-operated patients.

The data were evaluated using generally accepted results for the disease, such as the Quantititave MG Score (QMG) and the proportion of patients with no disease-related functional limitations, with the exception of Some muscle weakness, called minimal manifestation status. Many more thymectomy patients were able to achieve this minimal manifestation status than those who did not.

"When you look at the minimal event rates in thymectomy patients, they are about the highest of all MG patient populations after five to seven years of targeted therapy," said Wolfe.

He added that another important result of the clinical benefits observed in patients undergoing thymectomy is the resulting economic benefit.

"We have evidence at three and five years after surgery that the need for hospitalizations, such as intensive care admissions to treat exacerbations of MG, is reduced by about two-thirds compared to medical treatment alone, "he said.

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The research was funded by the National Institute of Neurological Diseases and Disorders of the National Institutes of Health (NIH). The NIH Clinical and Translational Science Grants to several institutions, including UB, the University of Alabama at Birmingham, the University of Kansas, the Heartland Institute for Clinical and Translational Research, the Center for Health Sciences of the University of University of Texas at San Antonio and the National Research Resource Center. The Muscular Dystrophy Foundation and the MG Foundation of American provided support for the initial planning of the MGTX trial.

The list of co-sponsors and their institutions is available in the document.