By Randall Osborne

The first biologic product for use against rheumatoid arthritis (RA), Immunex Corp.'s Enbrel, won approval from the FDA and will be available to patients "within several days," said a company spokesman.

"We're stuffing and shipping," said Tim Warner, the spokesman for Seattle-based Immunex. "We had it manufactured to scale, prepared and boxed."

Immunex had agreed to follow a strict set of FDA guidelines that would make launching the drug quick and simple following approval, mainly because of the high demand, Warner said.

"There's a unique interest among RA patients, who've been very active in seeking information about potential therapies," he said. "It affects many if not most of the joints, and painkillers don't necessarily help much."

Enbrel (etanercept), a genetically engineered protein — two molecules of recombinant human tumor necrosis factor (TNF) receptor — works by binding TNF, thus blocking its interaction with cells that respond to its signal. TNF is found at elevated levels in fluid around the joints of RA patients.

The FDA approved Enbrel for use in patients with moderate to severe RA who have not responded well to other treatments. The drug can be used with methotrexate, a standard RA treatment, if patients do not benefit enough from methotrexate alone. Enbrel was not approved to treat other types of arthritis, such as osteoarthritis, which is associated with aging.

Warner said the drug is priced at $110 per vial. The cost per patient per year, at two vials per week, will be $11,440. More than 2 million Americans are afflicted with RA, the FDA said, and as many as one-third to one-half suffer the moderate to severe version.

In September, an FDA advisory panel unanimously recommended approval of Enbrel, for which the company had filed its biologics license application in May. Immunex entered a $100 million promotion deal with Madison, N.J.-based American Home Products (AHP), which owns a majority interest in Immunex. (See BioWorld Today, Sept. 17, 1998, p. 1, May 11, 1998, p. 1 and Sept. 29, 1997, p. 1.)

The drug will be marketed by Wyeth-Ayerst Laboratories, a division of AHP with "the No. 1 sales force in rheumatology," Warner said.

"Our launch meeting is going on in Atlanta right now," he said late Monday afternoon, shortly after the FDA made public its decision. "We see this as a bellwether day for receptor technology."

Immunex's stock (NASDAQ:IMNX) closed Monday at $70.625, up $1.562. *