Two firsts for treating rheumatoid arthritis pain

Two first-of-their-kind products have been approved to help patients battle the pain of rheumatoid arthritis, a chronic disease that affects more than 2 million Americans. Arava (leflunomide) is the first oral treatment for active rheumatoid arthritis, and Etanercept (enbrel) is the first arthritis treatment produced by biotechnology.

Arava was approved in September for slowing the progression of the disease after clinical studies showed that the drug was effective in relieving the painful, swollen joints of rheumatoid arthritis and retarding damage the disease causes to joints. Arava is not, however, a cure for rheumatoid arthritis.

Because animal studies suggested the drug may cause birth defects, its labeling will carry a special warning stating that Arava should never be used by pregnant women or women of childbearing age who are not using reliable contraception. Also, because the drug remains in the body for a long time, the drug's labeling will recommend that women who want to become pregnant after taking Arava undergo a drug-elimination procedure.

The drug's labeling also will caution doctors to monitor liver enzymes of patients using Arava because clinical studies identified liver toxicity as a possible side effect. The drug is not recommended for patients with significant liver disease. Other side effects include diarrhea, hair loss, and rash.

Arava will be marketed by Hoechst Marion Roussel, Kansas City, Mo.

Etanercept, licensed by FDA in November, helps reduce the pain and swollen joints of moderate to severe active rheumatoid arthritis in patients who have not responded well to other treatments. It can be used in combination with methotrexate for patients who did not benefit enough from methotrexate alone.

Etanercept is not approved to treat less severe symptoms of rheumatoid arthritis or for osteoarthritis or other forms of the disease.

Etanercept binds to, and inhibits the action of, tumor necrosis factor, a naturally occurring protein in the body that promotes inflammation and is present at elevated levels in the fluid surrounding the affected joints of rheumatoid arthritis patients.

In clinical trials, about 59 percent of patients treated with etanercept experienced a significant reduction in symptoms such as swollen and painful joints after six months of treatment, compared with 11 percent of untreated patients.

Some patients treated with the new product developed reactions at the injection site, such as itching, pain or swelling, but the reactions were generally mild to moderate and lasted only a few days.

In children with moderate to severe juvenile rheumatoid arthritis, studies have shown results similar to those in adults. When possible, children should be up-to-date with vaccine immunizations before starting therapy with etanercept because it is not known whether treatment will affect immunization responses.

While clinical studies so far have not shown an increase in serious infections or malignancies in patients using etanercept, studies are under way to look at the product's long-term safety.

Etanercept will be marketed by Immunex Corp., Seattle, and Wyeth-Ayerst Laboratories, Philadelphia.

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