Genentech to Make Enbrel for Immunex

Immunex Corp. said Genentech Inc. agreed to begin making Enbrel in 2004, helping bolster the supply of Immunex’s top-selling treatment for rheumatoid arthritis.

Manufacturing constraints have limited Enbrel supplies and checked growth of the drug, which had sales of $762 million last year. Immunex has a waiting list of about 13,000 patients who want the drug. It last month notified others already on the drug to expect delays until June.

Amgen Inc., which is buying Immunex for about $16 billion, has said it expects to begin producing more Enbrel next year when it completes a new plant in Rhode Island.

Immunex’s agreement with Genentech is intended to ensure adequate supply of the drug until a second Rhode Island plant begins operating in 2005.

Shares of Immunex fell 26 cents to close at $28.92 on Nasdaq.