Potential Treatments for Sporadic Inclusion Body Myositis

Sporadic inclusion body myositis has proven to be the most challenging of the myositis diseases to treat. To date, no treatments have been discovered that can effectively delay or stop the progressive muscle weakness that inevitably leads to disability.

A great deal of effort is being invested, however, in trying to better understand this disease and develop some form of treatment and, of course, a cure. These are currently the medications that hold the most promise in this effort. Some of these are currently recruiting patients for clinical trials.

Arimoclomol is a compound that is believed to stimulate the repair of certain proteins in muscle cells, preventing these proteins from clumping. The compound showed some promise in a small initial clinical trial with sporadic inclusion body myositis patients and is currently being studied in a larger trial.

Bimagrumab (also known as BYM338) is a human monoclonal antibody developed to treat pathological muscle loss and weakness. In a clinical trial with sporadic inclusion body myositis patients, this compound showed that patients developed increase in muscle mass. Difficulties with the design of the trial, however, led to inconclusive results. This medication continues to be studied for other indications, and, if approved, may possibly be used off-label for sporadic inclusion body myositis. This is not a cure, however; it is a treatment for symptoms of muscle weakness only.

Follistatin (also known as AAV1-FS344) is a gene therapy-delivered protein that increases muscle strength and function. It has been shown to improve walking ability in patients with Becker muscular dystrophy and is currently being studied in patients with sporadic inclusion body myositis.

Rapamycin (also known as sirolimus) is an immunosuppressant drug that is currently used to prevent organ rejection in kidney transplant patients. Recently, a small clinical trial using this medication in patients with sporadic inclusion body myositis showed some hopeful results. It is expected that a larger trial will begin in 2018 or 2019.