Amgen Inc. and partner Wyeth Pharmaceuticals received FDA clearance to expand the Enbrel label in psoriatic arthritis to claim the TNF blocker inhibits disease progression.
Enbrel, a blockbuster developed by Wyeth and Immunex Corp., is approved in the U.S. to treat adult and juvenile rheumatoid arthritis, psoriatic arthritis and ankylosing spondylitis (spinal arthritis). Enbrel also is under FDA review as a treatment for psoriasis. (See BioWorld Today, Nov. 3, 1998; July 28, 2003; and July 9, 2003.)
As for the expanded label in psoriatic arthritis, Andrea Rothschild, spokeswoman for Thousand Oaks, Calif.-based Amgen, told BioWorld Today, "This continues to underscore the broad utility of this therapy. Psoriatic arthritis is very distinct from rheumatoid arthritis, but we are seeing the same kind of results in terms of inhibiting disease progression, and that may have important implications for long-term disease outcomes.
"Clearly, if you have a drug that not only improves the signs and symptoms, but halts the disease progression or inhibits it, and also is showing skin clearance in terms of the skin manifestation of the disease, that's pretty significant in terms of motivation to help patients," Rothschild said.
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, Amgen said in a prepared statement.
The psoriatic market in the U.S. is about 1 million patients, according to Amgen's figures. Approximately one-half of the market is appropriate for Enbrel as a treatment in both signs and symptoms and disease progression, Rothschild said.
Amgen has forecast U.S. sales of Enbrel to generate between $1.2 billion and $1.4 billion in 2003.
Rothschild wouldn't discuss the financial relationship between Amgen and Madison, N.J.-based Wyeth Pharmaceuticals, which owns rights to Enbrel outside North America. Amgen inherited the partnership by way of its acquisition of Immunex, of Seattle. (See BioWorld Today, July 17, 2002, and Dec. 18, 2001.)
The expanded label was approved based on a Phase III 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 placebo showed progressive joint destruction, Amgen said.
Adverse events were similar to those experienced in earlier RA clinical trials. Amgen said the rate of injection-site reactions in patients receiving Enbrel was statistically different compared to those receiving placebo (36 percent with Enbrel vs. 9 percent in placebo).
Amgen's stock (NASDAQ:AMGN) closed Monday at $66.20, down 28 cents.