VX-765, an orally- absorbed pro-drug of VRT-043198, is a potent and selective inhibitor of caspase-1 which belongs to the ICE/caspase-1 sub-family caspases.

Caspase-1, known as interleukin (IL)-1-converting enzyme, is responsible for the processing of a key inflammatory mediator IL-1β from an in active precursor to an active, secreted protein. In response to intracellular bacteria, caspase-1 is also reported to be involved in a rapid programme of cell death, termed pyroptosis in macrophages [1].

VX-765 is usually metabolized to an active molecular VRT-043198. In cultures of peripheral blood mononuclear cells stimulated with bacterial products, VRT-043198 inhibited the release of Interleukin (IL)-1β and IL-18, but had no affect the secretion of other cytokines such as IL-α, TNFα, IL-6 and IL-8 [2].

This product is also used in other models to illustrate the function of Caspase-1. Oral administration of VX-765 significantly reduced the severity of diseases and the inflammatory cytokines and chemokines secretion in the mouse model of rheumatoid arthritis and skin inflammation[1]. In addition, recent study demonstrated that VX-765 prevents CD4 T-cell pyroptotic death in a dose-dependent manner in HIV-infected lymphoid tissues [3].

Reference:
1.?Denes A, Lopez-Castejon G, Brough D. Caspase-1: is IL-1 just the tip of the ICEberg Cell Death Dis 2012,3:e338.
2.?Wannamaker W, Davies R, Namchuk M, Pollard J, Ford P, Ku G, et al. (S)-1-((S)-2-{[1-(4-amino-3-chloro-phenyl)-methanoyl]-amino}-3,3-dimethyl-butanoy l)-pyrrolidine-2-carboxylic acid ((2R,3S)-2-ethoxy-5-oxo-tetrahydro-furan-3-yl)-amide (VX-765), an orally available selective interleukin (IL)-converting enzyme/caspase-1 inhibitor, exhibits potent anti-inflammatory activities by inhibiting the release of IL-1beta and IL-18. J Pharmacol Exp Ther 2007,321:509-516.
3.?Doitsh G, Galloway NL, Geng X, Yang Z, Monroe KM, Zepeda O, et al. Cell death by pyroptosis drives CD4 T-cell depletion in HIV-1 infection. Nature 2014,505:509-514.