CBS Therapeutics Inc. is developing first-in-class inhibitors of cystathionine beta synthase that could synergize with existing therapies to treat both KRAS-mutant and wild-type metastatic colorectal cancer.

Cystathionine beta synthase (CBS) is found in many cell types and metabolizes the amino acid homocysteine to cystathionine by two different routes. One route produces hydrogen sulfide, a gas involved in normal vasorelaxation, angiogenesis and energy production. While studies have shown exogenous hydrogen sulfide promotes growth in cancer cell lines, the roles of endogenously produced hydrogen sulfide and CBS in cancer were undefined.