The NF-κB/Rel transcription factors, known to be involved in the regulation of pro-inflammatory cytokines and the pathogenesis of a variety of diseases, are present in the cytosol in an inactive state, complexed with inhibitory IκB proteins. NF-κB is activated upon degradation of IκB following IKK-α and IKK-β phosphorylation. IKK-ε, a homolog of IKK-α and IKK-β, can also activate NF-κB. IKK-ε is expressed predominantly in immune cells and is thought to play a role in the immune response. CAY10575 is a benzimidazole analog that inhibits IKK-ε with an IC50 value of ~15.8 µM.