and many medical centers asked the FDA to waive consent requirements in situations where the patient was at high risk of dying and relatives could not be reached. While some medical ethicists opposed waiving consent, the FDA approved the proposal in August 1998 for five medical centers. Development of LeukArrest was halted in April 2000 when interim data from phase III clinical trials did not meet Icos's goals of significantly reducing the chance of multiple organ failure and reducing the death rate from shock at 28 days. LeukArrest was also tested unsuccessfully for treatment of heart attack, multiple sclerosis, and stroke. Pafase Pafase, also known as rPAF-AH, was developed to treat severe sepsis. Pafase is the recombinant form of platelet-activating factor acetylhydrolase (PAF-AH, also known as lipoprotein-associated phospholipase A2), an enzyme made naturally by macrophages and found in human blood. PAF-AH inactivates platelet-activating factor, a phospholipid that plays a role in the inflammation seen in sepsis. The enzyme was discovered in the mid-1980s by graduate student Diana Stafforini and researchers Steve Prescott, Guy Zimmerman, and Tom McIntyre at the University of Utah. The gene that codes for Pafase was discovered by Icos. Early trials for sepsis showed that the drug reduced the death rate after 28 days and patients were less likely to develop severe respiratory problems. Icos also tested Pafase for acute respiratory distress syndrome (ARDS). In phase II trials for ARDS, Pafase reduced the death rate after 28 days and reduced the chance that the lungs of the patient would fail. However, Icos halted development in December 2002 when interim data from phase III trials for sepsis showed that the drug did not help patients survive. Scientists at Northwestern University later studied Pafase for necrotizing enterocolitis, and there is ongoing research on the enzyme for atherosclerosis at the University of Utah. Sitaxentan sodium and TBC3711 In June 2000, Icos and Texas Biotechnology formed a 50/50 partnership to research endothelin receptor antagonists for use in the areas of pulmonary hypertension and chronic heart failure. Two drugs, sitaxentan sodium (also spelled sitaxsentan) and TBC3711, were tested in clinical trials under the partnership. Sitaxentan was designed to treat pulmonary arterial hypertension, and TBC3711 was designed to treat cardiovascular diseases such as hypertension. In April 2003, Icos sold its part of the 50/50 partnership, including any share of sitaxentan and TBC3711, to Texas Biotechnology for $4 million at closing and another $6