Information Selonsertib (GS-4997) Selonsertib (GS-4997) is a highly selective and potent once-daily oral ASK1 inhibitor with potential anti-inflammatory, antineoplastic and anti-fibrotic activities. Targets ASK1 (Cell-free assay) 8.3(pIC50) In vivo An orally bioavailable inhibitor of apoptosis signal-regulating kinase 1 (ASK1), with potential anti-inflammatory, antineoplastic and anti-fibrotic activities. Upon oral administration, ASK1 inhibitor GS-4997 targets and binds to the catalytic kinase domain of ASK1 in an ATP-competitive manner, thereby preventing its phosphorylation and activation. This prevents the phosphorylation of downstream kinases, such as c-Jun N-terminal kinases (JNKs) and p38 mitogen-activated protein kinase (p38 MAPK). By preventing the activation of ASK1-dependent signal transduction pathways, GS-4997 prevents the production of inflammatory cytokines, down-regulates the expression of genes involved in fibrosis, suppresses excessive apoptosis and inhibits cellular proliferation.