Benznidazole is recommended for treatment of Chagas infection. Effects of combination therapy with benznidazole and posaconazole had not been tested in Trypanosoma cruzi carriers.

The objective of the STOP CHAGAS study was to evaluate the efficacy and safety of posaconazole and posaconazole in combination with benznidazole given orally for 60 days to reduce parasitemia as measured by qualitative Polymerase Chain Reaction (PCR) at the end of 120 days of follow-up post treatment in subjects with asymptomatic chronic Chagas disease.


  • Posaconazole demonstrated trypanostatic activity during treatment, but it is ineffective long-term in asymptomatic T. cruzi carriers.
  • Benznidazole monotherapy is superior to posaconazole, with high RT-PCR conversion rates sustained at one year.
  • Side effects lead to therapy discontinuation in 32 percent.
  • No advantages were observed with combined therapy versus benznidazole monotherapy.

The Principal Investigator of the STOP CHAGAS study was Carlos Morillo, then at PHRI.

Study Type

Interventional - Drug

Study Design

Randomized, active, placebo-controlled

NO. of Countries


NO. of Sites


NO. of Participants


Study Period




Schering-Plough (original sponsor)

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