ObjectiveTo investigate the safety, biological effects, and efficacy of the anti-tumor necrosis factor (TNF) antibody fragment, MAK 195F, in a phase II trial in patients with severe sepsis.DesignProspective, randomized, open label, placebo-controlled, dose-ranging, multicenter, multinational clinical trial.SettingSixteen academic medical centers' intensive care units in six European countries.PatientsOne hundred twenty-two patients with severe sepsis or septic shock who received standard supportive care and antimicrobial therapy.InterventionsPatients received one of three different doses of the anti-TNF antibody (0.1 mg/kg, 0.3 mg/kg, or 1.0 mg/kg) or placebo; the antibody or placebo was given in nine doses at 8-hr intervals over 3 days.Measurements and Main ResultsThere were no significant differences in mortality rates among the groups receiving various doses of the anti-TNF antibody or placebo, but patients with baseline serum interleukin (IL)-6 concentrations of more than 1000 pg/mL appeared to benefit from MAK 195F in a dose-dependent fashion. Increased circulating IL-6 concentrations, but not TNF concentrations, were found to be important prognostic indicators for mortality for the patients in the placebo and the two lower dosage groups but not in the high dosage group (1 mg/kg). IL-6 concentrations decreased during the first 24 hrs of treatment in all three anti-TNF groups but not in the placebo group. MAK 195F was well tolerated by all patients. Human antimurine antibodies developed in 40% of the patients receiving the antibody.ConclusionsThere was no increase in survival from sepsis for the patients receiving anti-TNF treatment in the overall study population. Retrospective stratification of patients by IL-6 concentrations suggests beneficial effects of the drug for patients with baseline circulating IL-6 concentrations of more than 1000 pg/mL. This hypothesis requires validation in a larger, blinded, prospective study.(Crit Care Med 1996; 24:733-742)