Alexion and Procter & Gamble (P&G) are developing pexelizumab (h5G1. 1-SC), a short-acting, recombinant complement C5 inhibitor for the potential treatment of complications of cardiovascular surgery, such as complement activation during cardiopulmonary bypass (CPB) procedures, for which it has completed phase II trials [275707]. By November 2001, the companies were also conducting two phase II trials for the treatment of acute myocardial infarction (MI) and by March 2002, patient accrual in the first of these MI trials (COMPLY) had been completed [429171],[443067]. In April 2002, accrual in the second MI trial (COMMA) was also completed [446377]. Results from the MI trials had been expected in the first half of 2002 [435888]. By January 2002, pivotal phase III trials had been initiated in patients undergoing coronary artery bypass graft (CABG) with CPB [435058]. The compound may also have potential in the treatment of stroke [188595]. In September 2000, the US FDA granted Alexion Fast Track status for pexelizumab for CPB patients [381531]. The company is collaborating with P&G to develop and commercialize this inhibitor drug for patients undergoing CPB during CABG [313015]. In December 2001, the terms of the collaboration were altered and as a result Alexion was to play an increased role in the development and marketing of pexelizumab in the US [433296]. Alexion licensed the complement protein C5 technology from Enzon Inc, developed during Enzon's short chain antigen binding (SCA) proteins program, in May 1996 [352743]. Analysts at US Bancorp Piper Jaffray predicted in January 2002 that pexelizumab has potential peak sales of US $350 million. At this time, approval for the CPB indication was expected in the US in the second half of 2004, and sales in 2005 were expected to reach US $50 million, rising to US $227 million in 2008. In the rest of the world, CPB approvals were expected to begin in the second half of 2005. Sales in 2006 were expected to reach US $35 million, rising to US $110 million in 2008 [438051].