Rare muscle inflammation the focus of various clinical trials

Ask The Doctors By Eve Glazier, M.D., and Elizabeth Ko, M.D.

Dear Doctor: My brother, who is 65, was diagnosed with inclusion body myositis about five years ago, and the muscles in his arms, legs and hands are deteriorating rapidly. He’s someone who loves life, so this is very hard to watch. His physician says there’s no cure. What can you tell me about the disease? Is it being studied anywhere?

Dear Reader: We’re very sorry to hear about your brother’s struggles. We know from experience how difficult it is to see a loved one be unwell and be unable to help.

Inclusion body myositis, also known as IBM, is a progressive degenerative muscle disease, sometimes also referred to as a muscle wasting disease. The word “progressive” means that once the disease process begins, it will continue to advance.

As you already learned, there is no treatment or cure for IBM at this time. However, advances in the areas of precision medicine and immunotherapy will hopefully lead to new methods to manage, if not cure, the disease.

Let’s start with what is known about inclusion body myositis.

There are two types of IBM. One, which is extremely rare, is inherited. It results from a genetic defect that is passed along from a parent’s DNA. The other form, which has no genetic link and is slightly more common, is known as sporadic. Sporadic IBM, also referred to as S-IBM, is seen most often in people 50 years and older. It is more common in men than in women.

Although the exact cause of S-IBM is not yet known, it is believed to be the result of a malfunction in the immune system. In autoimmune disorders, the body’s defense mechanisms mistakenly attack healthy tissue. In S-IBM, certain white blood cells attack muscle tissue and cause ongoing inflammation. There is also a second avenue of attack, which causes the muscle fibers to degenerate.

For many people, the first symptom of S-IBM is an increasing tendency to stumble, trip or fall. This is due to damage to the quadriceps, the large muscles of the thighs. The muscles of the wrists and fingers are also often affected.

Treatment at this time focuses on the use of corticosteroids to address inflammation, or drugs to suppress the immune system. However, several types of new drugs are now being studied in ongoing clinical trials. These are focused both on the inflammatory response in SIBM, as well as stopping the progression of muscle destruction. Although some participants in the clinical trials have shown modest or even good response to the drugs, the benefits thus far have proven to be short-term.

If you are interested in learning more about clinical trials for S-IBM, visit clinicaltrials.gov, a government website that lists studies receiving federal funding, as well as some that are funded by private industry.

For information about clinical trials at the National Institutes of Health Clinical Center, located in Bethesda, Maryland, call the NIH Patient Recruitment Office at (800) 411-1222. Or you can email prpl@mail.cc.nih.gov.