Fexinidazole: A Potential New Drug Candidate for Chagas Disease

Ivo Santana Caldas,André Talvani,Els Torreele,Michael P Pollastri,Lívia De Figueiredo Diniz,Álvaro Fernando Da Silva Do Nascimento,Isabel Mayer De Andrade,Bernadette Bourdin Trunz,Isabela Ribeiro,Tassiane Assíria Fontes Martins,Maria Terezinha Bahia

doi:10.1371/journal.pntd.0001870

Abstract

BackgroundNew safe and effective treatments for Chagas disease (CD) are urgently needed. Current chemotherapy options for CD have significant limitations, including failure to uniformly achieve parasitological cure or prevent the chronic phase of CD, and safety and tolerability concerns. Fexinidazole, a 2-subsituted 5-nitroimidazole drug candidate rediscovered following extensive compound mining by the Drugs for Neglected Diseases initiative and currently in Phase I clinical study for the treatment of human African trypanosomiasis, was evaluated in experimental models of acute and chronic CD caused by different strains of Trypanosoma cruzi.Methods and FindingsWe investigated the in vivo activity of fexinidazole against T. cruzi, using mice as hosts. The T. cruzi strains used in the study were previously characterized in murine models as susceptible (CL strain), partially resistant (Y strain), and resistant (Colombian and VL-10 strains) to the drugs currently in clinical use, benznidazole and nifurtimox. Our results demonstrated that fexinidazole was effective in suppressing parasitemia and preventing death in infected animals for all strains tested. In addition, assessment of definitive parasite clearance (cure) through parasitological, PCR, and serological methods showed cure rates of 80.0% against CL and Y strains, 88.9% against VL-10 strain, and 77.8% against Colombian strain among animals treated during acute phase, and 70% (VL-10 strain) in those treated in chronic phase. Benznidazole had a similar effect against susceptible and partially resistant T. cruzi strains. Fexinidazole treatment was also shown to reduce myocarditis in all animals infected with VL-10 or Colombian resistant T. cruzi strains, although parasite eradication was not achieved in all treated animals at the tested doses.ConclusionsFexinidazole is an effective oral treatment of acute and chronic experimental CD caused by benznidazole-susceptible, partially resistant, and resistant T. cruzi. These findings illustrate the potential of fexinidazole as a drug candidate for the treatment of human CD.

Highlights

One century after its discovery, American trypanosomiasis, or Chagas disease, remains a serious health problem in Latin America, where it affects 8–10 million people with 100 million at risk of acquiring the disease [1]
Fexinidazole is an effective oral treatment of acute and chronic experimental Chagas disease (CD) caused by benznidazolesusceptible, partially resistant, and resistant T. cruzi. These findings illustrate the potential of fexinidazole as a drug candidate for the treatment of human CD
This study describes the in vivo activity of fexinidazole against Trypanosoma cruzi, the protozoan parasite causing Chagas disease, using mice infected with parasite strains with varying susceptibility to benznidazole, the standard treatment for Chagas

Summary

Introduction

One century after its discovery, American trypanosomiasis, or Chagas disease, remains a serious health problem in Latin America, where it affects 8–10 million people with 100 million at risk of acquiring the disease [1]. Despite the superior in vitro potency and in vivo efficacy of these novel azole derivatives against T. cruzi, and the absence of cross-resistance with currently available drugs, response to drug treatment varies among the different strains of the parasite [3,4,5,6]. Current chemotherapy options for CD have significant limitations, including failure to uniformly achieve parasitological cure or prevent the chronic phase of CD, and safety and tolerability concerns. Fexinidazole, a 2-subsituted 5-nitroimidazole drug candidate rediscovered following extensive compound mining by the Drugs for Neglected Diseases initiative and currently in Phase I clinical study for the treatment of human African trypanosomiasis, was evaluated in experimental models of acute and chronic CD caused by different strains of Trypanosoma cruzi

Methods

Results

Discussion

Conclusion