NEW YORK (Reuters Health) – Three available drugs that belong to the newest class of drugs for treating rheumatoid arthritis — the tumor necrosis factor (TNF)-alpha blockers — are equally effective in treating this common joint disease, according to an analysis of several prior studies.

Still, the results suggest that it is generally best to start with an older drug like methotrexate and then add the newer agents if the treatment response is poor.

Although the three drugs – Remicade (infliximab), Enbrel (etanercept), and Humira (adalimumab) — were approved by the US Food and Drug Administration for treatment of rheumatoid arthritis between 1998 and 2003, there are no published “head-to-head” comparative studies, Spanish researchers point out in the journal BMC Musculoskeletal Disorders.

Led by Dr. Alberto Alonso-Ruiz at Cruces Hospital in Barakaldo, the research team conducted an analysis of 13 trials lasting at least 6 months involving 7,087 patients with rheumatoid arthritis. Comparison subjects were given either methotrexate, a standard treatment for the disease, or an inactive “placebo.”

The TNF-alpha blockers were generally comparable in their ability to control the signs and symptoms of rheumatoid arthritis, the findings indicate.

The TNF-alpha blockers provided the greatest benefit when added to the treatment regimen of patients who had a poor response to methotrexate. The drugs offered little added benefit if methotrexate was already working, and they were also more likely to cause side effects.

“Therefore,” Alonso-Ruiz and his associates conclude, “we advise against starting treatment with (TNF-alpha blockers) until a lack of adequate response to methotrexate is clearly documented.”

SOURCE: BMC Musculoskeletal Disorders, April 17, 2008.