Rituximab for the Treatment of Early Rheumatoid Arthritis (RA)

RA is an inflammatory disease that causes pain, swelling, stiffness, and loss of function in the joints. It occurs when the immune system, which normally defends the body from invading organisms, turns its attack against the membrane lining the joints. RA is commonly managed by DMARDs initiated early in the disease process, before irreversible joint damage occurs. The most common DMARD prescribed in the United States is MTX; this drug is well tolerated and has better efficacy compared to other DMARDs, but is inadequate in providing lasting improvement in individuals with RA. In patients with an inadequate response to MTX alone, the use of biologic agents, including TNF-blocking agents in combination with MTX, has become a standard therapeutic approach.

Rituximab (anti-CD20) is a man-made antibody used to treat certain types of cancer. The drug blocks the CD20 antigen found on the surface of B cells and is known to deplete B cells when administered intravenously. Previous research suggests B-cell activity is important in pathogenesis of RA, so B-cell depletion may decrease inflammation and other symptoms of RA. Rituximab has recently been approved by the FDA for use in combination with MTX for treatment of patients with moderately to severely active RA who have had an inadequate response to TNF-blocking agents. This study will examine the effects of rituximab on the immune response and disease activity in patients with early active RA who have not been treated with any disease-modifying agent. Levels of B and T cells and other markers of disease activity will be monitored during the study. The safety and tolerability of rituximab in this DMARD-naive population will be examined.

The expected duration of this study is 2.5 years. All participants will receive two intravenous infusions of rituximab in an outpatient setting at study entry and Week 2. Throughout the study, participants will receive MTX, systemic corticosteroids, and folic or folinic acid. MTX dosing will be re-evaluated by disease activity scores every month until Month 6 and again at Months 8, 10, and 12. Systemic corticosteroid doses will be modified based on the participant's health while in the study. Use of nonsteroidal anti-inflammatory drugs (NSAIDs) is permitted, but NSAID doses should not be changed during the study, if at all possible. NSAIDs will not be provided by this study.

There will be a maximum of 2 screening visits before study treatment, a baseline visit (Day 0), and 11 study visits. A physical exam, assessment for adverse events, and blood collection will occur at all study visits. Kidney and liver function tests and rheumatologic evaluations will occur at most study visits; participants will also be asked to complete a questionnaire on their health at most study visits. Arthroscopy (knee biopsy) on the more inflamed knee will occur at baseline and Month 3. Participants will be contacted by telephone the day after each arthroscopy and rituximab infusion.