National Editor

Already used off-label for psoriasis - and approved for rheumatoid arthritis and psoriatic arthritis - Amgen Inc.'s Enbrel (etanercept) won FDA approval for treating those with moderate to severe forms of the skin condition who are candidates for systemic therapy or phototherapy.

"It was an expected event," said Eric Schmidt, analyst with SG Cowen Securities Corp. in New York. Amgen's shares (NASDAQ:AMGN) closed Monday at $57.94, up $1.53.

Andrea Rothschild, spokeswoman for Thousand Oaks, Calif.-based Amgen, allowed that the approval had been figured into the stock price, but getting the label addition is "as significant to the [Enbrel] brand as the RA indication was five and a half years ago."

Enbrel is being used for psoriasis by about 3,500 dermatologists, although Amgen has not been allowed to actively detail the drug for the disease, Rothschild said. Another 5,000 to 6,000 more will be targeted, now that the new label has been OK'd.

The company also will conduct direct-to-patient advertising, she said. Of about 4.5 million people in the U.S. with psoriasis, about 1.5 million are afflicted with the moderate to severe form.

"About half of those aren't even seeing a dermatologist because they've given up on treatment," Rothschild told BioWorld Today. Of those who are being treated, about 60 percent are using topical drugs, which can be messy and inconvenient, she added.

"This is an opportunity that hasn't been tapped into," she said.

With Enbrel's approval for psoriasis, Amgen officially joins what has become a crowded market, but the tumor necrosis factor blocker has been leading the way for a while, Schmidt noted.

"Enbrel is the No. 1 biologic in the dermatology field, and that was without a label," he said.

Another TNF blocker used off-label against psoriasis is Malvern, Pa.-based Centocor Inc.'s Remicade (infliximab), approved for Crohn's disease and RA, the only biologic approved for both.

Other drugs against psoriasis include Raptiva (efalizumab) from Genentech Inc., of South San Francisco, and Amevive (alefacept) from Cambridge, Mass.-based Biogen Idec Inc. The monoclonal antibody Raptiva blocks the binding of LFA-1 to ICAM-1, thus inhibiting T cells from binding to key cells in the psoriasis reaction, rather than depleting T cells themselves. Amevive blocks activation of T cells by interfering in the LFA3/CD2 pathway. Both drugs were approved last year.

Another oral systemic treatment for psoriasis is Soriatane, a retinoic acid analogue approved in 1997 for severe psoriasis. Soriatane gained headlines earlier this year when Connetics Corp., of Palo Alto, Calif., entered an agreement to buy exclusive U.S. rights to it from Basel, Switzerland-based F. Hoffmann-La Roche Ltd. for $123 million. (See BioWorld Today, Feb. 10, 2004.)

More psoriasis therapies are lined up on the runway. Allergan Inc., of Irvine, Calif., in November submitted a new drug application to the FDA for its oral retinoid tazarotene. Allergan already markets a topical form, called Tazorac.

Humira (adalimumab), from Abbott Park, Ill.-based Abbott Laboratories, is another TNF blocker approved for RA that could get a psoriasis label in 2005 or 2006.

"[Humira] would potentially be the greatest competitor to Enbrel," Schmidt told BioWorld Today.

Another player is Isotechnika Inc., of Edmonton, Alberta, which in March reported data from a successful Phase II trial with its lead drug against psoriasis, known as ISA247.

"It's a cyclosporine analogue," Schmidt said. "Obviously, cyclosporine itself has proven too toxic for broad use," he added, and "the question for that compound" may involve toxicity issues, although Isotechnika said the Phase II research came up with no significant bad effects on blood pressure and lipid levels, and serum creatinine levels stayed within the acceptable reference range. (See BioWorld Today, March 11, 2003.)

At least until Humira reaches the market, Enbrel has little to worry about, Schmidt said.

"It helps to be the best," he said. "And this is."