Amgen submits psoriasis drug for marketing review

Amgen, the world's No. 1 biotechnology company, said it has asked US regulators to approve the sale of its rheumatoid arthritis drug, Enbrel, to treat the skin disorder psoriasis.

Amgen, based in Thousand Oaks, California, said it has applied to the US Food and Drug Administration to market Enbrel for moderate to severe plaque psoriasis. The inflammatory condition, marked by red, scaly patches of skin, affects some 7 million people in the United States, including about 1.5 million with more severe forms of the disease.

The injected drug has been sold for several years, in partnership with Wyeth, as a treatment for the painful joint disorder rheumatoid arthritis and psoriatic arthritis.

Sales of Enbrel totalled $802 million ($AUD1,214.25) last year and Amgen has projected 2003 sales of $1.2 billion to $1.4 billion.

Mike King, an analyst at Banc of America Securities, said the psoriasis indication is "a several hundred million dollar market opportunity," for Enbrel, adding that some 8 per cent of current prescriptions for the drug are being written by dermatologists.

Pivotal-stage trial results showed that three months of treatment with the drug, which blocks a protein called tumour necrosis factor, improved symptoms by at least 75 per cent in 49 per cent of patients when given in high doses. A lower dose improved symptoms by 75 per cent in 34 per cent of patients.

King said Enbrel is unlikely to be used to a great extent at the higher dose, largely because of cost issues.

Enbrel is approved for rheumatoid arthritis at the lower dose used in the psoriasis trial, a regimen that costs $10,000 to $12,000 per year.

A spokeswoman for Amgen declined to comment on whether the FDA application specifies a dosage level. She said the company will comment further after the release of its quarterly financial results on July 22.

Drug companies are eager to crack the psoriasis market, which analysts estimate could eventually be worth $5 billion. Regulators have already approved Amevive, a new drug from Biogen, and other drugs are being developed by Genentech and its partner Xoma, Johnson & Johnson and Abbott Laboratories.

Until recently, the only systemic treatments for the skin disorder were immunosuppressant drugs like methotrexate, but they can eventually damage organs like the heart or liver.

Amevive is designed to work by suppressing an immunity-boosting cell that plays a central role in psoriasis, while Enbrel works by blocking a protein that causes inflammation.

Amgen said Enbrel was generally well tolerated in the psoriasis studies, citing injection site reactions as the most frequent adverse side effect.

(Additional reporting by Toni Clarke)