FDA approves rituximab to treat rare disorders

FDA has approved rituximab (Rituxan, Genentech, a member of the Roche Group, and Biogen Idec) in combination with glucocorticosteroids for the treatment of 2 forms of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis, Wegener’s granulomatosis (WG) and microscopic polyangiitis (MPA).

Rituximab is the first FDA-approved drug for any form of vasculitis, a family of 15+ rare autoimmune diseases that can affect people of all ages, according to the Vasculitis Foundation (VF). There is no known cause or cure for 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. Both are considered orphan diseases because they each affect less than 200,000 people in the United States.

Rituximab 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 rituximab was demonstrated in a single controlled trial, in which 197 patients with WG or MPA were randomly assigned to receive either rituximab plus glucocorticoids once a week for 4 weeks or oral cyclophosphamide plus glucocorticoids daily to induce remission. After 6 months, 64% of patients treated with rituximab had complete remission compared to 53% of patients treated with cyclophosphamide.

Retreatment with rituximab was not formally evaluated; therefore, the safety and efficacy of retreatment with subsequent courses of rituximab has not been established. More data are needed to determine the safety of more than one course of rituximab and long-term safety of rituximab used in patients with WG and MPA. These questions will be further evaluated in a required post-marketing study.

Rituximab carries a Boxed Warning for infusion reactions, which can occur during infusion or within 24 hours afterward. Other Boxed Warnings for rituximab include rashes and sores in the skin and mouth (severe mucocutaneous reactions); and progressive multifocal leukoencephalopathy, a brain infection that generally is fatal. Rituximab 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.

Rituximab, 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.

In a VF statement, Executive Director Joyce Kullman, said, “This is the first FDA-approved drug for any form of vasculitis, and the VF is delighted for our patients and their families. . . Although the approval of Rituxan is encouraging, it has only been approved for 2 of the vasculitic diseases. We hope Rituxan is the first of many drugs that will augment and eventually replace the current standard treatments of corticosteroid, cytotoxic, and immunosuppressive drugs that have so many and sometimes devastating side affects for our patients.”