FDA Approves Wider Use of Popular Arthritis Drug
By Justin Gillis
Washington Post Staff Writer
Thursday, January 17, 2002; Page E05
The biotechnology industry's hottest new product in a decade just got hotter. Enbrel, an injectable drug that illustrates the potential of new treatments based on genetic knowledge, has been approved to treat an ailment known as psoriatic arthritis.
The drug is already on the market, and the new approval expands its sanctioned uses. The approval was granted late Tuesday by the Food and Drug Administration and announced yesterday by Enbrel's manufacturer, Immunex Corp. of Seattle.
Such expansions are common, but this one is particularly significant because it could eventually add $500 million a year to Enbrel's sales, by Wall Street estimates. That would make Enbrel one of the top-selling drugs ever developed by a biotech company. Securities analysts, who had factored the latest FDA approval into their estimates, peg Enbrel's sales potential at $3 billion to $5 billion a year by 2005.
Largely on the strength of those expectations, the world's largest biotech company, Amgen Inc. of Thousand Oaks, Calif., has agreed to buy Immunex for $16 billion in cash and stock. It will be far and away the biggest biotech merger ever, creating a West Coast titan big enough to compete with the drug industry's traditional giants, most of which are in New Jersey.
"Our conservative estimate is that Enbrel will be a $3 billion drug," Amgen spokesman Jeff Richardson said yesterday. "It may be much higher than that."
The drug, originally developed using genetic research, has already improved the lives of many patients with rheumatoid arthritis, a nasty condition in which the immune system attacks the body's joints.
Lately, some impatient doctors have been using Enbrel for psoriasis or psoriatric arthritis, knowing that, at a genetic level, those diseases have similarities with rheumatoid arthritis. This week's FDA action grants formal approval for such use in psoriatric arthritis, and it means patients will have an easier time getting insurance companies to pay for the drug, which can cost $12,000 per year.
"Unbelievably, it is the first drug that has been tested, and approved by the FDA, specifically for psoriatic arthritis," said Tara Rolstad, director of medical affairs at the National Psoriasis Foundation. "That is just a sign of the fact that this disease to date has not received very much attention."
Psoriatric arthritis is an ailment that appears, at least on the surface, to be a hybrid of psoriasis, a skin disease, and arthritis. Many patients diagnosed with psoriasis based on the red, scaly patches on their skin also have tender, swollen joints, but they do not necessarily realize the two syndromes are connected. In both instances, scientists say, an overactive immune system is attacking the very body it's supposed to protect.
Doctors come up with conflicting diagnoses for these patients, so it's hard to estimate the number of people with psoriatric arthritis. Immunex conservatively puts the number at 300,000 adults in the United States, while the National Psoriasis Foundation conducted a large survey recently that produced a figure closer to 1 million.
In human tests, 70 percent of patients on Enbrel showed improvement after 24 weeks of treatment, compared with 23 percent of patients on a placebo. Some patients saw their ailment all but disappear. Enbrel does pose risks, however. It suppresses a component of the immune system and therefore poses increased risks of infection, particularly in diabetics.
Immunex continues to test Enbrel in psoriasis, and expects to seek FDA approval for treating that disease. The company's biggest problem has been making enough of the drug to satisfy demand. A new factory in Rhode Island is due to open late this year.
Immunex and Amgen are seeking approval of their merger from shareholders and government agencies and hope to close the transaction by year-end. Enbrel would join Amgen's Epogen, which corrects a debilitating anemia in kidney patients, as the best-selling biotechnology drugs.
© 2002 The Washington Post Company