Eli Lilly has agreed to purchase ICOS, co-marketer of erectile dysfunction drug Cialis (tadalfil), for approximately $2.1 billion. Lilly and ICOS have been partners in Cialis since 1998 and launched the drug together in 2003, capturing 25% of the ED market in the US. “This transaction provides financial and operation al benefits to Lilly,” said CEO Sidney Taurel in a statement. “We also look forward to further developing the commercial potential of tadalfil through the pursuit of new indications.” The deal is expected to close in late 2006 or early 2007, with positive earnings results by 2008. In July, Lilly reported Cialis sales jumped 22% in the second quarter to $233.2 million. Lilly is scheduled to report its third quarter results Thursday.