(A) Macrophages harvested from C57BL-6 mice were treated with increasing doses of itacitinib 1 day in advance of being activated with 5 ng/mL LPS. Twenty-four hours after LPS treatment, supernatant was harvested and cytokine levels measured. (B) C57BL/6 mice were prophylactically orally dosed with vehicle, or 60 or 120 mg/kg of itacitinib b.i.d. for 3 days. Mice then received intraperitoneal injections of LPS (5 μg per animal). Two hours after injection, mice were euthanized and IL-6 levels were measured in the peritoneal lavage. Data represent mean ± SEM, and P values were calculated by two-way ANOVA. *P < 0.05, ***P < 0.001. Data are representative of two independent experiments.