Rituximab for the Treatment of Refractory Adult and Juvenile Dermatomyositis (DM) and Adult Polymyositis (PM)

Rituximab is a man-made antibody used to treat certain types of cancer. This study will determine whether rituximab is an effective treatment for adult and pediatric patients with dermatomyositis or polymyositis. Study hypotheses: 1) The time to improvement in Group A patients (receiving rituximab first) will occur significantly earlier than in Group B patients (receiving rituximab later). 2) The proportion of patients improved at Week 8 of the treatment phase will be significantly greater in Group A than in Group B.