Petrenko and colleagues, in 2021, presented the results of a study on a combination of CA IX inhibitor n-octyl disulfamate (OCT) with a pentacyclic triterpene 3-O-acetylbetulin (3-AC), a betulinic acid prodrug that shows selective cytostatic activity on human cancer cell lines in vitro and in vivo (Figure 14) [79]. The gene discussed is CA9; the disease is cancer.