Selective glucocorticoid receptor modulation inhibits cytokine responses in a canine model of mild endotoxemia
Selective glucocorticoid receptor modulators (GRMs) promise to reduce adverse events of glucocorticoids while maintaining anti-inflammatory potency. The present study tested the anti-inflammatory activity of two novel non-steroidal GRMs (GRM1: BI 607812 BS, GRM2: BI 653048 BS*H3PO4) in comparison to prednisolone in a canine model of low dose endotoxemia. This study compared the anti-inflammatory and pharmacokinetic profile of escalating daily oral doses of GRM1 (1, 2.5, 5 and 10 mg/kg) and GRM2 (0.1, 0.25 and 1 mg/kg) with prednisolone (0.25 and 0.5 mg/kg) and placebo after intravenous infusion of endotoxin (0.1 μg/kg) to Beagle dogs. This was followed by a 14-day evaluation study of safety and pharmacokinetics. Endotoxin challenge increased TNF-α ˜2000-fold and interleukin-6 (IL-6) 100-fold. Prednisolone and both GRMs suppressed peak TNF-α and IL-6 by 71–82% as compared with placebo. The highest doses of GRM1 and GRM2 reduced the mean body temperature increase by ˜30%. The endotoxin-induced rise in plasma cortisol was strongly suppressed in all treatment groups. Pharmacokinetics of both GRMs were non-linear. Adverse effects of endotoxemia such as vomiting were mitigated by GRM2 and prednisolone, indicating an antiemetic effect. During the 14-day treatment period, the adverse event profile of both GRMs appeared to be similar to prednisolone. Both GRMs had anti-inflammatory effects comparable to prednisolone and showed good safety profiles. Compounds targeting the glucocorticoid receptor selectively may provide an alternative to traditional glucocorticoids in the treatment of inflammatory disease.