FDA Approves Drug for Rare Blood Vessel Disorders

(Research.gov)

The U.S. Food and Drug Administration today approved Rituxan (rituximab) as a therapy for two rare disorders that cause severe vasculitis or blood vessel inflammation. The drug was developed by Biogen Idec in Weston, Massachusetts, and is manufactured by Genetech in South San Francisco, California.

The diseases approved for treatment by Rituxan — Wegener’s granulomatosis (WG) and microscopic polyangiitis (MPA) — affect people of all ages and ethnicities, and both genders. WG mostly affects the respiratory tract — sinuses, nose, trachea, and lungs — and kidneys, while MPA commonly affects the kidneys, lungs, nerves, skin, and joints. The vasculitis caused by these diseases can lead to tissue damage. Both disorders are considered orphan diseases by the FDA because they each affect less than 200,000 people in the United States.

Rituxan is an antibody that binds to the CD20 protein on the surface of cancerous and normal B-cells. In non-Hodgkin’s lymphoma and rheumatoid arthritis, Rituxan works with the body’s own immune system to eliminate CD20-positive B-cells.

The drug was first developed by Biogen Idec and approved in the U.S. and Europe in 1997-98 as a treatment for non-Hodgkin’s lymphoma, rheumatoid arthritis, and chronic lymphocytic leukemia. To treat WG and MPS, Rituxan works in combination with a type of steroids called glucocorticoids.

The safety and effectiveness of Rituxan were demonstrated in a single controlled clinical trial, where 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, however, was not formally evaluated. The safety and efficacy of retreatment with subsequent courses of Rituxan, therefore, has not been established. More data are needed to determine the safety of more than one course of Rituxan and long term safety of Rituxan in patients with WG and MPA. The FDA says these questions will be further evaluated in a required post-marketing study.

Read more: Pharma Companies Developing 460 Orphan Drugs

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