Use of combination of leflunomide with biological agents in treatment of rheumatoid arthritis.

An Expert Panel Meeting was held in May 2004 to assess experience with combination therapy with leflunomide and biological agents in the treatment of rheumatoid arthritis (RA), to identify both optimal use of such combinations and precautions for use. Eleven published prospective or retrospective studies were reviewed, principally evaluating combination of leflunomide with infliximab, as well as patient registry data. Available data suggest that combination therapies are more efficacious than monotherapies, reflecting the complementarity of mechanisms of action. Information on side effects remains contradictory, and tolerability of these combinations may vary between different patient groups. In some studies, tolerability is equivalent to that seen with monotherapy; in others a high rate of adverse events has led to frequent treatment discontinuation. Dermatological reactions may be a specific side effect of these combination therapies. Combination therapy is considered justified for treatment of patients diagnosed early who are at risk for rapid progression and for patients who fail to respond to monotherapy. The majority of participants favored adding biological agents to a previously established leflunomide monotherapy rather than starting both treatments simultaneously. On the other hand, combination therapy should be considered with caution in patients with a history of treatment failure, with hepatic comorbidity, or with other autoimmune disease, and in immunocompromised patients. When considering initiation of combination therapy, it is important to provide full information to the patient on the potential benefits and risks of such treatment and to integrate patients as far as possible into the decision-making process.