Recent Developments in Sterol 14-demethylase Inhibitors for Chagas Disease.

The protozoan parasite, Trypanosoma cruzi, causes the most prevalent parasitic infection in the American continent. It gives rise to life-long infection in humans and results in severe cardiomyopathy or other life-threatening manifestations (Chagas disease) in ~30% of those infected. Animal models and clinical studies indicate that etiological treatment of the infection reduces the risk of developing the disease manifestations. Unfortunately, the existing chemotherapeutics have suboptimal antiparasitic activity and cause significant side effects in many patients, thus better anti-trypanosomal drugs are greatly needed. The sterol biosynthesis pathway has received attention as a target for the development of new drugs for Chagas disease. In particular, inhibitors of sterol 14-demethylase (CYP51) are shown to be extremely active on Trypanosoma cruzi in vitro and in animal models. Antifungal drugs (i.e. azoles) in clinical use or in clinical studies have been extensively tested preclinically on Trypanosoma cruzi with posaconazole and ravuconazole demonstrating the most promising activity. As a result, posaconazole and a pro-drug of ravuconazole (E1224) are currently being evaluated in Phase II studies for Chagas disease. Additional CYP51 inhibitors that are specifically optimized for anti-Trypanosoma cruzi activity are in development by academia. These represent an alternative to proprietary antifungal drugs if the latter fall short in clinical trials or are too expensive for widespread clinical use in disease endemic countries. The research over the next few years will help define the role of CYP51 inhibitors, alone or in combination with other drugs, for managing patients with Chagas disease.