Disease severity varies widely in patients with
severe sepsis.
Eritoran tetrasodium (
E5564), a TLR4 antagonist, blocks the binding of
endotoxin and is being evaluated as a novel
therapy for
severe sepsis. This analysis aimed to assess the efficacy of
eritoran based on severity of illness and similar effects in other recent
sepsis trials. Prospective covariates from a randomized, double-blind, placebo-controlled, phase 2 trial were analyzed for treatment interaction measured by 28-day mortality. Five statistical interaction methodologies were used. The modified intent-to-treat population (n = 292), all-cause 28-day mortality was as follows: placebo, 33.3% (32/96);
eritoran 45 mg/105 mg, 29.6% (58/196). Logistic regression analysis identified Acute Physiology and Chronic Health Evaluation II scores, predicted-risk-of-mortality scores,
IL-6, age, sex, race, and
eritoran use as associated with survival. Significant treatment interactions were observed (
eritoran vs. placebo) for baseline covariates: Acute Physiology and Chronic Health Evaluation II (P = 0.035), predicted-risk-of-mortality scores (P = 0.008), number of organ failures (P = 0.079), international normalized ratio (P = 0.05), and acute physiology score (P = 0.039). I analysis showed that 38% of the total
eritoran treatment variance was explained by the severity-of-illness heterogeneity rather than by chance. No interactions observed with other variables. Consistent with the finding in this
eritoran trial, other
sepsis trials (
IL-1 receptor antagonist, TNFsr-p55,
antithrombin,
drotrecogin alfa-activated) also demonstrated significant treatment by severity interaction. Potential survival benefits of
eritoran in
severe sepsis patients were associated with high severity of illness. These findings were used to design a phase 3 trial. Similar treatment by severity-of-illness interaction was found in most recent
sepsis trials.