Rituximab (pronounced “ri-TUX-i-mab”) is an antibody that was originally created in the laboratory. It is designed to interact with B cells, which are a type of white blood cells that play a role in the initiation and development of RA. Rituximab (brand name: Rituxan) decreases the number of B cells in the circulation. In fact, people who take rituximab have demonstrated near-complete depletion of B cells in their bloodstream within two weeks of taking the first dose of medication. Most people showed a sustained peripheral B-cell depletion that lasted for at least six months. The B cells returned to their normal level gradually thereafter. Plasma cells (the cells that make antibodies) are not depleted by rituximab, however; likewise, levels of the antibodies that are necessary to fight infections do not decline.
Rituximab was originally sold as a novel treatment for lymphoma (a cancer of the lymph nodes). Patients with both lymphoma and RA who underwent treatment with rituximab noticed that their RA symptoms were significantly improved after treatment, leading to further investigation of this antibody as a treatment for RA. Rituximab is now indicated for the treatment of patients with RA who have shown an inadequate response to previous treatment with one or more TNF inhibitor therapies.
Rituximab is given to patients as two intravenous infusions, whose delivery is separated by two weeks. This course of treatment is repeated every six to nine months. The dose of rituximab will be different for different patients. The dose that is used may depend on a number of things, including your weight.
This medication should be administered only by or under the immediate supervision of your doctor. Rituximab is given in combination with methotrexate, which boosts the effectiveness of both treatments. Additionally, before each infusion, it has been recommended that methylprednisolone be given. This steroid decreases the likelihood of an infusion reaction, and probably contributes to the effectiveness of the treatment as well.
Like many other arthritis drugs, rituximab should be given only after you have discussed all of the risks and benefits associated with its use. For many people, being treated with this antibody can result in significant improvements in their RA symptoms. Unfortunately, there are also side effects that anyone contemplating treatment should discuss with their physician:
- Some patients may experience an allergic reaction during the infusion of rituximab. This reaction can be as mild as minor itching and hives or as serious as low blood pressure and difficulty breathing. Because of this possibility, rituximab is administered with corticosteroids, which tend to blunt any allergic reaction.
- Rituximab may decrease the number of white blood cells, red blood cells, and platelets. If you experience a decrease in these blood constituents, you may be at increased risk for anemia, infections, and bleeding.
- Any drug that depresses the immune system puts the person treated at increased risk for infection. People treated with rituximab have been noted to have an increase in infections of the sinuses, lungs, and urinary tract. If you are taking rituximab (or any other drug that suppresses the immune system), you are also at risk for serious infections that can result in hospitalization or death if not treated immediately. Consequently, if you experience fever or chills, cough, shortness of breath, sore throat, or pain or difficulty passing urine, you should contact your doctor immediately or go to the emergency room.