Immunex has developed and launched etanercept, a soluble TNF receptor (TNFR) fusion protein, for the treatment of early and moderate to severely active rheumatoid arthritis (RA). Etanercept was launched as a first-line agent in the US for the treatment of moderate-to-severe active RA in June 2000 [375481]. It can also be used in conjunction with methotrexate (MTX) in patients who do not respond adequately to MTX alone [303266], [310436]. It was launched in the EU in November 2000 [388846]. Enbrel was also launched for the treatment of polyarticular-course juvenile RA (JRA) patients who have an inadequate response to one or more disease-modifying antirheumatic drugs (DMARDs) in May 1999. Additionally, it is in phase III trials for psoriatic arthritis and a BLA filing for this indication is expected for the first half of 2001 [364948]. Etanercept was launched in the US in November 1998, for the treatment of moderate-to-severe RA in patients with inadequate responses to one or more DMARDs, or in combination with MTX in patients who do not respond adequately to MTX alone [306175]. The drug was subsequently approved by the US FDA for use as a first-line therapy to treat patients with moderately to severely active RA [375481]. In February 2000, Wyeth Europe received clearancefor etanercept in 15 EU countries by the EMEA for the treatment of active arthritis in adults when the response to DMARDs has been inadequate [354844]. It has since been launched in the UK (June 2000) [388840], and by October 2000 had been launched in all EU member states [388846]. In November 1998, the company filed a supplemental BLAfor the treatment of children and teenagers with moderately to severely active polyarticular course JRA. In May 1999, etanercept was approvedfor this indication by the US FDA and approvedfor this indication in Europe in February 2000 [307061], [310436], [326379]. The increasing understanding of the role of TNF in a number of other diseases has led to its clinical assessment in these areas. Following positive clinical results in phase II studies [317562], [315793], (320666], (359789], (373980] in patients with chronic heart failure, etanercept entered phase III trials for this indication in June 1999 [330068], and a BLA filing for this indication is expected in 2003 [396110]. Additionally, Immunex initiated a phase III trial of etanercept in psoriatic arthritis in March 2000, and as of May 2000, the company was planning a BLA filing for this indication in the first half of 2001 [364948]. An open-label trialfor the treatment of Crohn's disease is in progress in Belgium [367,039], and results from this trial were presented at Digestive Disease Week in May 2000 [379907]. While WO-09103553 claims the recombinant human receptor, the fusion protein consisting of the etanercept domain and the immunoglobulin region was disclosed in WO-09406476. In February 1997, US-05605690 was issued to Immunex for methods of using etanercept to treat diseases mediated by TNF. The patent also claims methods of using recombinant etanercept to decrease the levels of TNF in RA patients [235456]. In June 1999, Immunex strengthened its patent estate covering the product with a patent licensing agreement for Genentech's immunoadhesin patents covering the product [327250]. A royalty agreement with Serono SA and Immunex on sales of etanercept was agreed in 1999. The agreement reflected the strength of Ares-Serono's intellectual property status [352813]. In June 1999, Lehman Brothers predicted Immunex's sales at US $300 million in 1999, rising to peak annual sales of US $1.5 billion [328701]. Salesfor the drug's first full quarter on the market in 1999 were US $59.7 million [330068]. By November 1999 the drug had made sales of US $500 million; Immunex expects the drug will generate over US $2 billion in annual sales by 2004 [353185]. In September 2000, Merrill Lynch reported that if sales of the drug continue at the present rate then it is likely that demand will temporarily outstrip supply in 2001. Resolution of the supply issue is expected by 2002. Also in September 2000, Merrill Lynch lowered their estimate of ENBREL sales in 2001 from US $1 billion to $927 million. In the long-term, Merrill Lynch believe that the drug has the potential to exceed US $5 billion in sales in the US [382577].