In a randomised study of heparin versus placebo (XPRESS) in 1935 adult severe sepsis patients, all treated with drotrecogin alfa (activated), prophylactic heparin did not adversely affect mortality (heparin 28.3% versus placebo 31.9% in the overall ITT population, and heparin 30.3% versus placebo 26.9% in patients with multiple organ dysfunction treated within 24 hours of their first sepsis-induced organ dysfunction (n=890)).