The immune-modulating drug leflunomide is effective as co-therapy with drugs that block the inflammation-producing protein TNF in people with rheumatoid arthritis, according to a report published this month.

Rheumatoid arthritis, or RA, occurs when the immune system attacks the tissues that line the joints, leading to pain, inflammation and deformity. Rheumatoid arthritis is more common in women than in men, and often strikes people in their 30s or 40s.

In addition to its immune-modulating properties, the drug leflunomide also has anti-inflammatory activity and other studies have demonstrated its efficacy as a so-called disease-modifying antirheumatic drug (DMARD).

Dr. Axel Finckh from Geneva University Hospital, Geneva, Switzerland and colleagues compared the safety and effectiveness of different drug therapy regimens combining anti-TNF agents and leflunomide, the chemotherapy drug methotrexate, which is also used to treat RA, or other conventional DMARDs, in a large population-based cohort of rheumatoid arthritis patients.

The various combinations of DMARDs (including leflunomide) and anti-TNF agents showed no differences in their impact on the progression of joint damage, which was insignificant with all regimens. The different drug combinations also showed no differences in terms of functional disability progression, or evolution of arthritis activity over time.

The overall incidence of side effects, time to occurrence of side effects, and specific types of adverse events did not differ significantly between the therapeutic combinations, nor did the odds of discontinuing therapy.

“Taken together,” the investigators conclude, “these results suggest that leflunomide and potentially other DMARDs offer an effective and safe alternative to methotrexate as co-therapy in combination with anti-TNF agents.”

SOURCE: Annals of the Rheumatic Diseases, January 2009.