E5 murine monoclonal antiendotoxin antibody in gram-negative sepsis: a randomized controlled trial. E5 Study Investigators.

Context: Knowledge and understanding of gram-negative sepsis have grown over the past 20 years, but the ability to treat severe sepsis successfully has not.

Objective: To assess the efficacy and safety of E5 in the treatment of patients with severe gram-negative sepsis.

Design: A multicenter, double-blind, randomized, placebo-controlled trial conducted at 136 US medical centers from April 1993 to April 1997, designed with 90% power to detect a 25% relative risk reduction, incorporating 2 planned interim analyses.

Setting: Intensive care units at university medical centers, Veterans Affairs medical centers, and community hospitals.

Patients: Adults aged 18 years or older, with signs and symptoms consistent with severe sepsis and documented or probable gram-negative infection.

Intervention: Patients were assigned to receive 2 doses of either E5, a murine monoclonal antibody directed against endotoxin (n = 550; 2 mg/kg per day by intravenous infusion 24 hours apart) or placebo (n = 552).

Main Outcome Measures: The primary end point was mortality at day 14; secondary end points were mortality at day 28, adverse event rates, and 14-day and 28-day mortality in the subgroup without shock at presentation.

Results: The trial was stopped after the second interim analysis. A total of 1090 patients received study medication and 915 had gram-negative infection confirmed by culture. There were no statistically significant differences in mortality between the E5 and placebo groups at either day 14 (29.7% vs 31.1%; P = .67) or day 28 (38.5% vs 40.3%; P = .56). Patients presenting without shock had a slightly lower mortality when treated with E5 but the difference was not significant (28.9% vs 33.0% for the E5 and placebo groups, respectively, at day 28; P = .32). There was a similar profile of adverse event rates between E5 and placebo.

Conclusions: Despite adequate sample size and high enrollment of patients with confirmed gram-negative sepsis, E5 did not improve short-term survival. Current study rationale and designs should be carefully reviewed before further large-scale studies of patients with sepsis are conducted.