The U.S. Food and Drug Administration today approved Rituxan (rituximab), in combination with glucocorticoids (steroids), to treat patients with Wegener's granulomatosis (WG) and microscopic polyangiitis (MPA), two rare disorders that cause blood vessel inflammation (vasculitis).
Vasculitis in patients with WG and MPA can lead to tissue damage. WG mostly affects the respiratory tract (sinuses, nose, trachea, and lungs) and kidneys, while MPA commonly affects the kidneys, lungs, nerves, skin, and joints. Both of these diseases affect people of all ages and ethnicities, and both genders. The causes of these disorders are unknown, and both are considered orphan diseases because they each affect less than 200,000 people in the United States.
"This new indication for Rituxan provides the first approved therapy for these two orphan diseases," said Curtis Rosebraugh, M.D., M.P.H., director of the Office of Drug Evaluation II in the FDA's Center for Drug Evaluation and Research.
Rituxan is an antibody that is manufactured through biotechnology methods. The drug works by greatly reducing the number of specific immune cells in the blood, known as B cells.
The safety and effectiveness of Rituxan was demonstrated in a single controlled trial, in which 197 patients with WG or MPA were assigned at random to receive either Rituxan plus glucocorticoids once a week for four weeks or oral cyclophosphamide plus glucocorticoids daily to induce remission. After six months, 64 percent of patients treated with Rituxan had complete remission compared to 53 percent of patients treated with cyclophosphamide.