Etanercept. Immunex.

Abstract

Immunex has developed and launched etanercept, a soluble TNF receptor (TNFR) fusion protein, for the treatment of rheumatoid arthritis (RA). It has also been developed for various TNF-mediated conditions such as congestive heart failure, endometriosis and multiple sclerosis. Etanercept has been launched as a second-line agent in the US for the treatment of moderate-to-severe RA and can be used in conjunction with methotrexate in patients unresponsive to methotrexate alone. It is also available in the EU. In 2000, it was in phase III trials for psoriatic arthritis and an NDA filing for this indication was expected for the first half of 2001. In July 2001, the sBLA was filed, and in September 2001, the FDA granted the sBLA Priority Review status. As of January 2001, etanercept was in phase III trials for congestive heart failure, with sNDA filing expected in 2002; however, by March 2001, these had been halted, as it did not appear that statistical significance would be reached for the efficacy endpoints. Further data analysis was being undertaken at this time, before a final decision was taken. In April 2001, Merrill Lynch reported that development for this indication was to be halted. Sales for the drugs first full quarter on the market in 1999 were US $59.7 million. By November 1999 the drug had made sales of US $500 million; Immunex expected the drug to generate over US $2 billion in annual sales by 2004. In September 2000, Merrill Lynch reported that if sales of the drug continued at the present rate then it is likely that demand would temporarily outstrip supply in 2001. Resolution of the supply issue was expected by 2002. Also in September 2000, Merrill Lynch lowered their estimate of sales in 2001 from US $1 billion to $927 million. In the long-term, Merrill Lynch believed that the drug has the potential to exceed US $5 billion in sales in the US. In April 2001, Merrill Lynch predicted that etanercept prescribed for RA would generate sales of US $71 in 2002 rising to US $600 million in 2005. In October 2001, Morgani Stanley reported that Enbrel continues to be the primary source of revenue of Immunex (US $198.1 million). It was also reported that if launched for CHF, an estimated peak year revenue was likely to be US $500 million. The company maintains a website containing additional information about etanercept at http://www.enbrelinfo.com.