New Approval Sought for ENBREL to Slow Joint Damage and Improve the Signs and Symptoms of Early, Active Rheumatoid Arthritis

SEATTLE - Immunex Corporation (NASDAQ: IMNX) announced today that the company has filed a supplemental biologics license application (sBLA) with the U.S. Food and Drug Administration (FDA) for ENBRELR (etanercept), seeking a new label for the drug to slow structural damage and to improve the signs and symptoms of early, active RA. Immunex co-markets ENBREL in North America with Wyeth-Ayerst Laboratories, a division of American Home Products Corporation (NYSE: AHP).

"Irreversible damage can occur as early as two years into the disease process of rheumatoid arthritis, making early diagnosis and proper treatment absolutely essential," said Scott W. Baumgartner, MD, an ENBREL clinical investigator.

The FDA approved ENBREL on November 2, 1998 to treat moderately to severely active rheumatoid arthritis in patients who have an inadequate response to one or more disease-modifying anti-rheumatic drugs (DMARDs). The FDA included children and teen-agers (age 4-17 years) in the ENBREL label when it granted the drug a new indication on May 28, 1999 for the treatment of moderately to severely active polyarticular-course juvenile rheumatoid arthritis.

This new filing for ENBREL to slow the progression of rheumatoid arthritis and to treat the signs and symptoms of early, active RA is based on the results of a recently completed Phase III clinical trial, the summary results of which were announced in May 1999. The primary endpoints of this study showed that ENBREL may slow the progression of the disease and reduce the signs and symptoms. ENBREL was found to be generally well tolerated in this clinical trial. The most common events reported in this trial in patients receiving ENBREL were mild to moderate injection site reactions (34 percent) that did not complicate treatment.

A complete analysis will be presen
'"/>

Contact: Tim Warner
warnert@immunex.com
206-470-4193
Immunex Corporation
15-Jul-1999