OBJECTIVES

To determine, in a randomised placebo-controlled trial, if cutaneous adverse reactions during treatment (CARDT) with Benznidazole occur as often as with Nifurtimox, and whether the dose and duration of treatment change that frequency.

METHODS

We conducted the EQUITY trial (NCT02369978), allocating Trypanosoma cruzi seropositive adults with no apparent clinical disease to a 120-day, blinded treatment with Benznidazole, Nifurtimox, or Placebo (ratio 2:2:1). Active treatment groups included either 60-day conventional-dose (60CD) regimens (Benznidazole 300 mg/day or Nifurtimox 480 mg/day, followed or preceded by, 60 days of placebo) or 120-day half-dose (120HD) regimens (Benznidazole 150 mg/day or Nifurtimox 240 mg/day). CARDT had blinded adjudication as moderate to severe during the follow-up visits.

RESULTS

Among 307 participants, 42 CARDT (17.1%, 95% confidence interval [CI] 12.6-22.4) occurred in 246 receiving active treatment, compared to two CARDT (3.3%, 95% CI 0.0-11.3) in 61 participants receiving placebo. In 122 patients treated with Benznidazole, there were 31 CARDT (25.4%, including eight severe), compared to 11 CARDT (8.9%, including four severe) in 124 individuals treated with Nifurtimox (p < 0.001). Among the 125 participants assigned to the 120HD regimen, there were 26 CARDT (20.8%, including six severe), compared to 16 CARDT (13.2%, including six severe) among 121 in the 60CD group (p = 0.005). The agent-regime interaction was not significant (p = 0.443). Eleven participants (25%) with CARDT did not complete their treatment.

CONCLUSION

CARDT occurred more frequently with Benznidazole treatment, particularly with longer exposure despite the half-dose regimen. Clinicians should consider these differences when discussing treatment options with patients receiving nitro derivative agents.