The U.S. Food and Drug Administration announced April 19 that it had approved rituximab, in combination with glucocorticoids, for the treatment of people with Wegener’s granulomatosis and microscopic polyangiitis.
Wegener’s granulomatosis and microscopic polyangiitis are related, rare, autoimmune diseases that cause vasculitis. The approval of rituximab (Roche’s Rixutan) offers clinicians an alternative to cyclophosphamide, a current standard treatment for these disorders.
In one manufacturer-funded, randomized, controlled trial (n = 197) that enrolled people with Wegener’s granulomatosis and microscopic polyangiitis, 64% of subjects who were treated with rituximab plus glucocorticoids achieved remission in 6 months, compared with 53% of those treated with cyclophosphamide plus glucocorticoids (N. Engl. J. Med. 2010;363:221-32).
Patients in the study were not re-treated with rituximab after relapse, however, and more "data are needed to determine the safety of more than one course of Rituxan and long-term safety of use of Rituxan in patients with WG and MPA," the FDA said in a news release. "These questions will be further evaluated in a required post-marketing study."
Rituximab, a monoclonal antibody with indications for some types of lymphoma, leukemia, and some autoimmune disorders, works by reducing the number of B cells in the blood. In people with Wegener’s granulomatosis and microscopic polyangiitis, the percentage of activated peripheral-blood B lymphocytes correlates with disease activity.
The medication, which is administered by intravenous infusion, carries boxed warnings on its label for infusion reactions (which can occur during or after infusion), for rashes and sores in the skin and mouth, and for progressive multifocal leukoencephalopathy, which is usually fatal. Rituxan is not recommended for use in patients with severe, active infections, the FDA said.