A second large controlled clinical study of E5, a monoclonal antibody to endotoxin: Results of a prospective, multicenter, randomized, controlled trial

Objective: To evaluate the safety and efficacy of E5, a murine, monoclonal antibody directed against endotoxin, in the treatment of patients with Gram- negative sepsis. Design: A multicenter, randomized, double-blind, placebo- controlled trial. Setting: Fifty-three hospitals across the United States, including university medical centers, Veterans Affairs Medical Centers, and community hospitals. Patients: 847 patients were randomized into this study. Enrolled patients met criteria for three conditions: a) known or suspected Gram-negative infection; b) clinical evidence of sepsis; and c) signs of end- organ dysfunction. Patients with refractory shock were excluded from the study. Interventions: Two doses of E5 (2 mg/kg/day by intravenous infusion 24 hrs apart), or placebo that was identical in appearance were administered. In addition, all patients received standard supportive therapy and broad- spectrum antibiotics. Measurements and Main Results: The primary end point was mortality over 30 days. Secondary outcome measures included the resolution and prevention of organ failure in the same two populations. Additionally, the safety of E5 was evaluated. There was no significant improvement in survival over 30 days among patients with Gram-negative sepsis who received E5 compared with those patients who received placebo (n = 530;p = .21). In addition, E5 did not improve survival for patients with Gram- negative sepsis and organ failure (n = 139;p = .3). However, a significantly greater percentage of patients with Gram-negative sepsis experienced resolution of major organ failure if they received E5, compared with those patients who received placebo (n = 139; 48% E5 vs. 25% placebo; p = .005). This result extended to all patients who entered the study with one or more major organ failures, regardless of the etiology of the infection (n = 225; 41% E5 vs. 27% placebo; p = .024). E5 also provided protection against the development of some organ failures, but significant prevention was only observed for adult respiratory distress syndrome (p = .007) and central nervous system dysfunction (p = .050). Hypersensitivity reactions attributable to E5 occurred in 2.6% of patients. An asymptomatic antibody response occurred in 44% of the E5-treated patients and in 12% of the patients who received placebo. Conclusions: In this study, E5 did not reduce mortality in nonshock patients with Gram-negative sepsis whether or not those patients also had organ failure. However, E5 did result in greater resolution of organ failure in patients with Gram-negative sepsis. This benefit extended to those patients with suspected Gram-negative etiology. This finding is important because patients with suspected Gram-negative sepsis and organ failure can be identified without waiting for culture results. In addition, E5 resulted in the prevention of adult respiratory distress syndrome and central nervous system organ failure. However, more studies are needed to determine if this result can be extended to organ failure in general. E5 is safe as a treatment for patients with Gram-negative sepsis.