NEW YORK – Rituximab may offer an alternative treatment for children whose juvenile dermatomyositis does not respond to available therapies, depending on the outcome of an ongoing trial, Dr. B. Anne Eberhard said at a meeting sponsored by New York University.
There are no U.S. Food and Drug Administration–approved medications for juvenile dermatomyositis (JDM).
The RIM (Rituximab in Myositis) trial is a randomized, phase II, placebo-phase controlled, multicenter trial investigating the effect of rituximab on refractory dermatomyositis in children and adults. The study intended to enroll 50 children with JDM, and it will assess efficacy, safety, and determinants of treatment response and disease pathogenesis, including clinical, demographic, and immunopathologic factors.
The RIM trial results will be presented at the annual meeting of the American Academy of Rheumatology in November 2010, Dr. Chester V. Oddis said in an interview.
The study is sponsored by Genentech Inc., Biogen Idec Inc., and the U.S. National Institute of Arthritis and Musculoskeletal and Skin Diseases, according to Dr. Oddis, who is the principal investigator and a professor of rheumatology at the University of Pittsburgh.
Dr. Eberhard noted that prednisone and methotrexate are the mainstays of treatment, for now. However, outcomes can be unsatisfactory either because symptoms remain poorly controlled or because side effects occur.
JDM is a relatively rare idiopathic inflammatory myopathy that can be physically disabling, disfiguring, and life threatening if left unchecked.
To facilitate diagnosis of JDM, the Childhood Myositis Assessment Scale (CMAS) was recently developed to allow clinicians to assess children for JDM in the office without the need for specialized equipment. The CMAS is a 14-activity, observational, performance-based assessment that measures physical function, strength, and endurance, explained Dr. Eberhard, who is a pediatric rheumatologist at the Albert Einstein College of Medicine in New York. For instance, it can be used to compare, from one visit to another, how well a child can raise his head or leg, go from a supine to sitting position, rise from a chair, or step on a stool. An abbreviated 9-maneuver test is also available.
Dr. Eberhard outlined other relatively simple ways to diagnose JDM in the office or at the bedside. The first is visual examination of the body, with a focus on skin changes, including the characteristic malar or butterfly rash on the bridge of the nose, cheeks and face; the classic reddish/purple heliotrope rash; and Gottron’s papules on the extensor surfaces of the fingers. The rash typically appears on skin areas that are exposed to the sun, including elbows, knees, and ankles, so sunscreens and sun avoidance are advised for JDM patients. About 25% of patients present with subcutaneous calcinosis, which eventually affects 70% of patients.
To look for vasculopathy, examine the nail-bed capillaries with an ophthalmoscope, said Dr. Eberhard. In contrast to their normal, straight, “picket-fence” appearance, the capillaries in children with JDM show dilation and extensive branching; there may even be capillary loss. “You can quantify the disease and monitor improvement with treatment by examining nail-bed capillaries,” she said.
Symmetrical proximal weakness is another hallmark of JDM. Dr. Eberhard said that she immediately thinks of JDM when she hears that a child is having difficulty getting up the school bus stairs.
An urgent response is required if a child says that food is “sticking to his mouth”. This suggests a bulbar muscle weakness of central origin, with impaired swallowing and the potential for aspiration. This may necessitate placing the child on a soft diet or even hospitalization, said Dr. Eberhard.
JDM can produce other serious sequelae, including pulmonary fibrosis and perforation of the esophagus or small bowel.
The original five diagnostic criteria that were first presented in 1975 did not change for the subsequent 35 years (N. Engl. J. Med. 1975:292:344-7). In addition to symmetrical proximal weakness and rash, the diagnostic criteria are raised serum muscle enzymes, electromyogram evidence of myositis, and histologic evidence of myositis. Diagnosis of JDM requires the presence of four of the five criteria, she said.
Dr. Eberhard had no relevant financial disclosures.
Image above courtesy: Dermatology Online Journal via Wikipedia Commons.
