MCTD: Is It Just Letters?

“These categories help us stratify and communicate in clinical practice,” said Dr. Distler. Moreover, he pointed out that classification systems are ultimately developed to help develop better clinical trials. He argued that the debate itself has led to an unfortunate dearth of research on MCTD, and Dr. Christopher-Stine added that this has impaired the development of targeted treatment strategies.

Dr. James noted that because the U.S. Food and Drug Administration has not specifically approved any therapies for MCTD, patients sometimes can’t get approved for specific medications if they have the diagnosis on record. Moreover, they often can’t qualify for participation in clinical trials, even if they also meet criteria for a diagnosis, such as SLE or systemic sclerosis, because they have a concurrent autoimmune disease. “We’re doing our patients a disservice by giving them another diagnosis that keeps them from actively participating in studies and potentially getting new therapies,” she noted.

Dr. James shared some key learning points that have broader implications, irrespective of whether one finds the pro or con arguments more convincing. She remarked that patients positive for U1-RNP antibodies may need additional screening, such as echocardiograms, pulmonary function tests and chest X-ray or computed tomography scan, regardless of whether they have a diagnosis of MCTD or another connective tissue disease.

Dr. James also added that it’s very common for patients to present with symptoms of multiple autoimmune diseases, although usually practitioners focus on just one. “Sometimes that helps our patients, but other times not so much,” she said. “We need paths to trials and insurance coverage for medications for patients who don’t clearly follow just one set of classification criteria.”

Ruth Jessen Hickman, MD, a graduate of the Indiana University School of Medicine, is a medical and science writer in Bloomington, Ind.

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