Editor note: On 3/01/2006, Rituxan was FDA approved to be used in combination with methotrexate to treat rheumatoid arthritis by reducing the signs and symptoms in adult patients who have moderately-to-severely active rheumatoid arthritis and have failed one or more anti-TNF drugs e.g. Enbrel (etanercept), Remicade (infliximab), or Humira (adalimumab). See: Rituxan Approved For Rheumatoid Arthritis - The Facts of Rituxan
Rituxan Showing Promise
Promising results from the latest research involving rituximab have been published in the June 17, 2004 issue of The New England Journal of Medicine. The international study is led by Jonathan C.W. Edwards, M.D., renowned for his work on the B-cell depletion therapy, at the University College London.
Rituximab, also known as Rituxan and Mabthera, works by targeting B-cells. The optimism surrounding this treatment is based on its ability to precisely target a specific type of immune cell, perhaps paving the way for other "smart" treatments for arthritis and related diseases, as well as other diseases. The drug is already approved for the treatment of non-Hodgkin's lymphoma.
Arthritis medications, until now, have treated only the symptoms or modified the disease process with a more broad, less specific approach. The lack of specificity can result in killing healthy cells along with diseased cells.
Rheumatoid arthritis is an autoimmune disease in which antibodies are mistakenly turned against the body's own joint linings, causing the joints to become swollen, inflamed, and painful. The inflammatory process leads to the destruction and deformity of affected joints. B-cells manufacture the antibodies which go haywire in autoimmune disease.
About The Study
The randomized, double-blind, controlled study involved 161 patients with active rheumatoid arthritis, despite prior treatment with methotrexate. The study participants were randomly assigned one of the following four treatments:
The responses, defined by the criteria of the American College of Rheumatology and the European League against Rheumatism, ACR and EULAR respectively, were analyzed at week 24 and 48. At week 24, the percentage of patients achieving a 50 percent improvement in symptoms according to ACR criteria (known as ACR50 response) was:
In all groups treated with rituximab an even higher percentage achieved 20 percent improvement of symptoms. At week 24, analysis revealed that all ACR responses (20, 50, 70) were maintained in the rituximab-methotrexate group.
Reportedly the majority of adverse events occurred with the first rituximab infusion. At 24 weeks, serious infections occurred in 2.5 percent of the control group and in 3.3 percent of the rituximab groups. One study participant on rituximab died of pneumonia though it was not concluded that the drug was responsible. Chest infection was noted as a possible danger.
It was concluded that in patients with active rheumatoid arthritis despite treatment with methotrexate, a single course of two infusions of rituximab, alone or in combination with methotrexate or cyclophosphamide, provided significant improvement in symptoms at both 24 and 48 weeks. It also was concluded and reported that more testing must be done before widespread use of rituximab for rheumatoid arthritis is approved. Other drugs which target B-cells are also being developed and are in clinical trials.
Related Resources - Rituxan (Rituximab)
Related Resources - B-Cell Depletion Therapy
Sources: NEJM (Volume 350:2572-2581, Number 25), Efficacy of B-CellTargeted Therapy with Rituximab in Patients with Rheumatoid Arthritis, June 17, 2004; Associated Press, Drug Appears Effective Against Arthritis