Part 1: Structure–Activity Relationship (SAR) investigations of fused pyrazoles as potent, selective and orally available inhibitors of p38α mitogen-activated protein kinase

A novel class of fused pyrazole-derived inhibitors of p38α mitogen-activated protein kinase (MAPK) is disclosed. These inhibitors were evaluated for their ability to inhibit the p38α enzyme, the secretion of TNFα in a LPS-challenged THP1 cell line and TNFα-induced production of IL-8 in 50% human whole blood. This series was optimized through a SAR investigation to provide inhibitors with IC50 values in the low single-digit nanomolar range in whole blood. Further investigation of their pharmacokinetic profiles led to the identification of two potent and orally bioavailable p38 inhibitors 10m and 10q. Inhibitor 10m was found to be efficacious in vivo in the inhibition of TNFα production in LPS-stimulated Lewis rats with an ED50 of 0.1 mg/kg while 10q was found to have an ED50 of 0.05–0.07 mg/kg.

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