Mortality: Afelimomab 54.0% vs. placebo 57.7% (NS, p = 0.36). SOFA/MODS Δ and labs: MODS showed earlier resolution trend (NS); IL-6 levels significantly reduced at 8 h and 72 h with afelimomab. Safety: Similar AE profiles, immunogenicity (16% anti-mouse IgG) without clinical allergy, IL-6 test predicted higher mortality in positive vs. negative (55.8% vs. 39.6%, p < 0.001). Here, IL6 is linked to allergic disease.