Efficacy and safety of available treatments for visceral leishmaniasis in Brazil: A multicenter, randomized, open label trial

Background There is insufficient evidence to support visceral leishmaniasis (VL) treatment recommendations in Brazil and an urgent need to improve current treatments. Drug combinations may be an option. Methods A multicenter, randomized, open label, controlled trial was conducted in five sites in Brazil to evaluate efficacy and safety of (i) amphotericin B deoxycholate (AmphoB) (1 mg/kg/day for 14 days), (ii) liposomal amphotericin B (LAMB) (3 mg/kg/day for 7 days) and (iii) a combination of LAMB (10 mg/kg single dose) plus meglumine antimoniate (MA) (20 mg Sb+5/kg/day for 10 days), compared to (iv) standard treatment with MA (20 mg Sb+5/kg/day for 20 days). Patients, aged 6 months to 50 years, with confirmed VL and without HIV infection were enrolled in the study. Primary efficacy endpoint was clinical cure at 6 months. A planned efficacy and safety interim analysis led to trial interruption. Results 378 patients were randomized to the four treatment arms: MA (n = 112), AmphoB (n = 45), LAMB (n = 109), or LAMB plus MA (n = 112). A high toxicity of AmphoB prompted an unplanned interim safety analysis and this treatment arm was dropped. Per intention-to-treat protocol final analyses of the remaining 332 patients show cure rates at 6 months of 77.5% for MA, 87.2% for LAMB, and 83.9% for LAMB plus MA, without statistically significant differences between the experimental arms and comparator (LAMB: 9.7%; CI95% -0.28 to 19.68, p = 0.06; LAMB plus MA: 6.4%; CI95% -3.93 to 16.73; p = 0.222). LAMB monotherapy was safer than MA regarding frequency of treatment-related adverse events (AE) (p = 0.045), proportion of patients presenting at least one severe AE (p = 0.029), and the proportion of AEs resulting in definitive treatment discontinuation (p = 0.003). Conclusions Due to lower toxicity and acceptable efficacy, LAMB would be a more suitable first line treatment for VL than standard treatment. ClinicalTrials.gov identification number: NCT01310738. Trial registration ClinicalTrials.gov NCT01310738
Author summary Visceral leishmaniasis remains a worldwide public health concern with high mortality even when proper treatment is instituted. There is a need to develop efficacious, safer and shorter treatment alternatives as the current options suffer from high toxicity and long treatment duration. Combination therapies emerge as an alternative, and WHO has encouraged the conduct of studies to evaluate drug combinations where evidence for current treatment regimens is not available. In Brazil, there is no local evidence to support the current treatment recommendations. Therefore, a clinical trial was conducted in five hospitals in Brazil to evaluate the efficacy and safety of the current available treatments—meglumine antimoniate, amphotericin B deoxycholate and liposomal amphotericin B—and of a combination of liposomal amphotericin B, single dose, and meglumine antimoniate, in a shorter administration regimen. Preliminary safety results led to the discontinuation of the amphotericin B deoxycholate treatment arm and a planned interim analysis resulted in the trial interruption. The final results, comparing liposomal amphotericin B and liposomal amphotericin B plus meglumine antimoniate to the standard meglumine antimoniate treatment, did not show a statistically significant difference in cure rates, though cure rate was higher in the liposomal amphotericin B group. Liposomal amphotericin B treatment showed a better safety profile compared to meglumine antimoniate. These results will support future changes in treatment protocols in Brazil and potentially in Latin America.