The Associated PressThe Food and Drug Administration has rejected an application to expand the use of rheumatoid arthritis treatment Rituxan for patients with earlier stages of the disease, biotech drug developers Genentech Inc. and Biogen Idec said Saturday. Rituxan is approved to treat patients with moderate-to-severe cases of the disease who are treated first with methotrexate and another class of anti-rheumatic drugs, according to a statement from South San Francisco-based Genentech and Cambridge, Mass.-based Biogen. The companies had hoped to have the drug approved for use in patients sooner, after they try only methotrexate. But the FDA declined to support the expanded use due to a risk for the potentially fatal brain disease, progressive multifocal leukeoencephalopathy, for which there is no reliable treatment. The companies said that risk is rare. They have reports of three cases of this disease occurring in about 100,000 rheumatoid arthritis patients treated with Rituxan. The FDA also updated the drug's labeling to give doctor's more information on how to treat patients with the drug again, after they have already tried it. A Genentech spokeswoman said the FDA's decision doesn't affect current approvals for the drug, which also treats different types of blood cancer.