Rituximab (Rituxan®)

Rituximab is an antibody used against a type of white blood cell protein called B cells. B cells are a part of the immune system important for making antibodies that help fight infection. In some autoimmune diseases, such as rheumatoid arthritis and lupus, the body’s B cells produce harmful antibodies that result in inflammation and tissue damage. The goal of Rituximab is to bind to and destroy these B cells. rituximab initially was created as an anticancer drug to help with cancers of the B cells called lymphoma and leukemia.

The dose of rituximab is 1,000 mg intravenously on days one and 15, given with an intravenous steroid, usually Solu-Medrol® 250 mg each time. The dose of rituximab may be adjusted by your rheumatologist. Rituximab is not yet Food and Drug Administration (FDA)-approved for treating rheumatic diseases, but several studies have shown encouraging results in patients suffering from lupus or rheumatoid arthritis.

Infusion reactions. Rituximab is an antibody partially made up of mouse protein. If you previously had an adverse reaction to Remicade, which also has a component of mouse protein, caution needs to be used with rituximab. Rituximab can result in infusion reactions that cause low blood pressure. Rarely, more severe reactions, including asthma-like reactions and skin rashes, have been described. Some patients who have used rituximab for treating blood cancers died of severe infusion reactions with the development of pneumonia, respiratory distress and heart attack. Fortunately, this has not been reported with its use in rheumatic diseases, where it appears to be safer. Also, the infusion of Solu-Medrol with the rituximab seems to prevent most infusion reactions.

Infections. There is an increased risk of bacterial and viral infections for six months to 18 months after rituximab, until normal B cell levels return. Annual flu vaccination and the pneumonia vaccine (Pneumovax) are recommended.

Low blood counts. Occasionally, low blood counts have been reported. Therefore, periodic blood counts will be checked.

Based on currently available studies, about 70 percent of patients can expect a 20 percent improvement in rheumatoid arthritis and 43 percent of patients can expect a 50 percent improvement. Similar improvements have been seen with lupus. Effects appear to last for six months to 12 months, and even longer in some patients.

Since rituximab depletes B cells, the levels of B cells often are measured before and at some point after rituximab therapy.

Since rituximab is not yet approved by FDA for treating lupus or rheumatoid arthritis, this drug usually will be used after most conventional therapies have failed. Usually, your rheumatologist will need to apply on your behalf to obtain insurance coverage for this medication. Infusions are given at our infusion services (at the 3800 Building at Park Nicollet Clinic—St. Louis Park) by nurses familiar with its use.