FDA approves Rituxan to Treat Two Rare Vasculitis Disorders

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Earlier this week, the U.S. Food and Drug Administration (FDA)approved Rituxan (rituximab), in combination with glucocorticoids (steroids), to treat patients with with two rare vaculitis (blood vessel inflammation) disorders.

The two disorders are Wegener’s granulomatosis (WG) and microscopic polyangiitis (MPA). The cause is not known for either disorder. Both are considered orphan diseases because they each affect less than 200,000 people in the United States.

Inflammation in Wegener’s granulomatosis affects the blood vessels and other tissues, damaging important organs of the body by limiting blood flow to those organs and destroying normal tissue. WG mainly affects the respiratory tract (sinuses, nose, trachea [windpipe], and lungs) and kidneys though all organ systems may be affected. WG can affect people at any age. Men and women are equally affected. It is rare in African Americans compared with Caucasians.

The vasculitis of microscopic polyangiitis (MPA) can lead to organ damage as with WG. As with WG, MPA affects people of all ages and both genders. The organs most commonly affected in MPA are the kidneys, lungs, nerves, skin, and joints.

“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.

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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 cyclosphosphamide.

Retreatment with Rituxan was not formally evaluated; therefore, the safety and efficacy of retreatment with subsequent courses of Rituxan has not been established. 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. These questions will be further evaluated in a required post-marketing study.

Rituxan carries a Boxed Warning for infusion reactions, which can occur during infusion or within 24 hours afterwards. Other Boxed Warnings for Rituxan include rashes and sores in the skin and mouth (severe mucocutaneous reactions); and progressive multifocal leukoencephalopathy, a brain infection that generally is fatal. Rituxan is not recommended for use in patients with severe, active infections.

The most common side effects in study participants with WG and MPA included infection, nausea, diarrhea, headache, muscle spasms, and anemia.

Rituxan, which has been marketed since 1997, is also indicated for the treatment of patients with non-Hodgkin’s lymphoma, chronic lymphocytic leukemia, and rheumatoid arthritis.

Rituxan is manufactured by San Francisco-based Genentech, a member of the Roche Group.

Source
Food and Drug Administration
National Institute of Allergy and Infectious Diseases: Wegener’s Granulomatosis
Office of Rare Disease Research: Microscopic Polyangiitis

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