FDA panel recommends new arthritis drug

By Rhonda Rowland
CNN Medical Unit

(CNN) -- Patients suffering from rheumatoid arthritis could soon have a new treatment option.

A Food and Drug Administration advisory panel, in a 6-2 vote, recommended approval of anakinra, to be marketed as Kineret, for patients who have failed standard therapies for rheumatoid arthritis.

"We've seen a good response in 40 percent of patients studied," said Dr. Stanley Cohen, medical director of Radiant Research in Dallas, Texas. "Patients reported they have less pain and feel better overall. They significantly improved in measures of physical disability."

The FDA, which usually follows the recommendations of the advisory panel, should make a final decision within six months.

Rheumatoid arthritis is an autoimmune disease causing pain and joint swelling. It is the most severe and disabling type of arthritis.

RESOURCES Read more about Kineret from the FDA Arthritis Drugs Advisory Committee

Inflammatory mechanisms known as cytokines appear to play a key role in the disease process. Kineret works by inhibiting a cytokine known as interleukin-1 (IL-1). Two other agents already on the market, Enbrel and Remicade, inhibit a second cytokine known as tumor necrosis factor (TNF).

"The beauty is this [Kineret] is another option, another kind of inhibitor, so if a patient is intolerant or doesn't respond to a TNF inhibitor they can try this," Cohen told CNN.

Some patients don't respond or can't tolerate TNF inhibitors because of the side effects, said Dr. Hayes Wilson of Piedmont Rheumatology in Atlanta, Georgia.

"We throw the book at some patients and nothing works," he said. "Unfortunately some can't take the infusion of Remicade because it causes hypotension. And some who take Enbrel get a very bad skin reaction. So with them we're stuck again. It would be great to have something else to try."

Kineret is given by daily injection and side effects appear to be similar to those of TNF inhibitors, including soreness at the injection site and a slight increase in infections.

"Most people have both cytokines, so the next question is, would it be better to take both together, would results be much better if both were inhibited," said Dr. John Klippel, medical director of the Arthritis Foundation.

Studies have not been done to determine if it is safe or effective to take both cytokine inhibitors together.

"At this point I wouldn't feel comfortable using them or recommending to my colleagues that they be used in combination," Cohen said.

Immunex, the maker of Enbrel, is starting studies with its own IL-1 inhibitor.

"We think IL-1 is a good target," said Dr. Leslie Garrison, senior vice president of clinical research and development at Immunex. "We do have data on the additive or synergic effect of the two inhibitors together and want to see how they work alone and in combination."

It's estimated that 2.1 million Americans have rheumatoid arthritis, most of them women. Kineret is manufactured by Amgen Incorporated.