United States of America. The Food and Drug Administration has approved a new genetically engineered protein, etanercept (Enbrel: Immunex and Wyeth-Ayerst), that helps reduce the symptoms of moderate to severe active rheumatoid arthritis in patients who have not responded well to other treatments. It can also be used in combination with methotrexate if patients do not benefit enough from use of methotrexate alone. Etanercept is not approved to treat other types of arthritis, such as osteoarthritis.

About 37% of patients treated with the new product developed injection site reactions, such as itching, pain or swellings, that were generally mild to moderate and lasted only a few days. Less than 1% of patients experienced an allergic reaction when etanercept was given, and no severe reactions were seen.

Although it is theoretically possible that etanercept may affect the body’s defences against infections and malignancies, clinical studies to date have not shown an increase in serious infections or malignancies. However, the company is conducting further studies to look at the long-term safety of the product.

Etanercept has also been studied in 54 children aged 4 to 17 years with moderate to severe juvenile rheumatoid arthritis with results similar to those of the adult studies. It is recommended that, if possible, children be up-to-date with current vaccine immunization guidelines before starting therapy with etanercept because it is not know whether immunization responses will be affected by treatment.

References: HHS News P98-35 dated 2 November 1998.