FDA approves Roche's Rituxan for rare disorders

The US health regulators approved Roche Holding AG's big selling arthritis and cancer drug Rituxan for treating two rare disorders that cause blood vessel inflammation. The US Food and Drug Administration approved Rituxan, in combination with certain steroids, to treat patients with Wegener's granulomatosis and microscopic polyangiitis.

Both disorders are considered orphan diseases as they affect less than 200,000 people in the United States. The causes of these disorders are unknown, the FDA said on its website. The drug, also known as rituximab, is already approved to treat rheumatoid arthritis, non-Hodgkin's lymphoma and chronic lymphocytic leukemia. It is an antibody that works by binding itself to a specific protein found on the surface of malignant and normal B-cell lymphocytes, enlisting the body's own immune system to to kill marked cells. Rituxan is manufactured by San Francisco-based Genentech, which was acquired by Switzerland-based Roche in 2009.