The U.S. Food and Drug Administration (FDA) has approved an expanded indication for Enbrel (etanercept) to inhibit the progression of structural damage of active arthritis in patients with psoriatic arthritis. The approval is being announced by Amgen and Wyeth Pharmaceuticals, a division of Wyeth.

Enbrel is the first and only approved therapy for both the inhibition of structural damage and the reduction in signs and symptoms of patients with psoriatic arthritis.

Enbrel is the only fully human anti-TNF receptor approved to reduce signs and symptoms, improve physical function, and inhibit structural damage in patients with moderately to severely active rheumatoid arthritis (RA), and to reduce the signs and symptoms and inhibit the progression of structural damage in patients with active psoriatic arthritis. Enbrel is the only biologic therapy approved for first-line treatment of RA patients, and can be used in combination with methotrexate or alone. It is approved to reduce the signs and symptoms of moderately to severely active polyarticular-course juvenile rheumatoid arthritis (JRA) in patients who have had an inadequate response to disease-modifying medicines. It is also the first biologic approved to treat the signs and symptoms in patients with active ankylosing spondylitis (AS).

"This is the first time a large clinical trial has demonstrated inhibition of radiographic progression of joint damage in people with psoriatic arthritis," says Willard Dere, M.D., vice president of clinical development for Amgen. "These data underscore the benefits of treating psoriatic arthritis patients with Enbrel."

Approval was based on a phase 3 study evaluating 205 patients with active psoriatic arthritis. Enbrel demonstrated inhibition of joint damage over a one-year study period, while x-rays of patients receiving a placebo showed progressive joint destruction.

"Enbrel has now been shown to inhibit underlying joint damage in two distinct diseases, rheumatoid arthritis, and now, psoriatic arthritis", says Victoria Kusiak, M.D., vice president of global medical affairs and North American Medical Director of Wyeth Pharmaceuticals. "As with rheumatoid arthritis, treatment with Enbrel can improve the painful and debilitating symptoms of psoriatic arthritis. "

Adverse events were similar to those reported in previous clinical trials of Enbrel in patients with rheumatoid arthritis. There was no increase in the number of serious adverse events occurring in patients treated with Enbrel compared to those receiving placebo. Only the rate of injection site reactions (ISRs) in patients receiving Enbrel was statistically different compared to those receiving placebo (36 per cent with Enbrel versus 9 per cent in placebo-treated patients).

Psoriatic arthritis is a chronic inflammatory disease of the joints and connective tissue. The disease combines joint pain and swelling that can lead to crippling debilitation with inflamed and irritated scaly red patches of skin on the body. The disease can be difficult to diagnose, particularly in its milder forms and earlier stages. Up to one million people in the U.S. population have psoriatic arthritis.

The benefits and long-term tolerability profile of Enbrel have been established in the treatment of over 180,000 patients worldwide across all indications.

Enbrel acts by binding TNF, one of the dominant inflammatory cytokines or regulatory proteins that play an important role in both normal immune function and the cascade of reactions that causes the inflammatory process of psoriatic arthritis, RA and AS. The binding of Enbrel to TNF renders the bound TNF biologically inactive, resulting in significant reduction in inflammatory activity.