Belnacasan (VX-765), and its active metabolite VRT- 043198, is a novel and irreversible IL-converting enzyme/ caspase-1 inhibitor. VRT-043198 exhibits 100- to 10,000-fold selectivity against other caspase-3, -6 and -9. It exhibited potent inhibition against ICE/caspase-1 and caspase-4 with Ki of 0.8 nM and less than 0.6 nM, respectively. And VRT-043198 also inhibits IL-1β release from both PBMCs and whole blood with IC50 of 0.67 uM and 1.9 uM, respectively. Belnacasan inhibits the release of IL-1, IL-18 and IL-33. Belnacasan has shown to inhibit acute partial seizures in preclinical models and has shown activity in preclinical models of chronic partial epilepsy that do not respond to currently available compounds for epilepsy. In addition, it seems to reduce disease severity and the expression of inflammatory mediators in models of rheumatoid arthritis and skin inflammation. Belnacasan had been in phase II clinical trials by Vertex for the treatment of epilepsy. However, this study has been terminated later.