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.

Nivocasan (aka GS-9450) was discovered by LG Life Sciences and developed by Gilead Sciences. Nivocasan is an irreversible inhibitor of caspase 1, 8, and 9, and therefore able to prevent apoptosis. Nivocasan has been investigated as a treatment option for Hepatic fibrosis and Non-alcoholic steatohepatitis related to Hepatitis C infection. It had advanced to Phase II clinical trials before the development program was suspended.

Pralnacasan is a potent, non-peptide inhibitor of interleukin-1beta converting enzyme (ICE, aka Caspase-1). It was originally discovered by Vertex Pharmaceuticals and licensed for development to Aventis Pharma. In 2003 Aventis and Vertex Pharmaceuticals agreed to voluntarily discontinue development based on results from a 9-month animal toxicity trial that showed liver abnormalities due to chronic high doses of pralnacasan. Pralnacasan has also been investigated for the treatment of Partial Epilepsy; advancing to Phase II clinical trials.

MDL-201053, (DL-ALANINE)- (Z-FA-FMK) is an irreversible inhibitor of cysteine proteases, such as cathepsin B, L, and S. The compound has also inhibitited papain and cruzain. Z-FA-FMK has been shown to selectively inhibit effector caspase-2, caspase-3, caspase-6, and caspase-7 without affecting initiator caspase-8 and caspase-10 while showing minimal toxicity to normal mammalian cells in vitro. Due to Z-FA-FMK's effector caspase specificity, the compound has been recorded to inhibit some forms of caspase mediated apoptosis. The compound has been observed to be an effective in time dependent inactivation of cathepsin B isozymes from a number of tissues. Studies show Cathepsin B-like activity plays a role in the cascade of proteolytic cartilage destruction. Z-FA-FMK is an inhibitor of cathepsin H. This compound has been shown to block the production of IL1-α, IL1-β, and TNF-α induced by LPS in macrophages by inhibiting NF-κB pathways. Z-FA-FMK blocks not only NF-kappaB activation but inhibits, also, T cell blast formation, and prevents cells from entering and leaving the cell cycle revealing demonstrating immunosuppressive abilities. Z-FA-FMK is a very effective viral inhibitor that can prevent reovirus replication in vitro and reovirus-mediated myocarditis, as well as reovirus-mediated oncolysis, in vivo.

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.