Assessing in vitro and in vivo activity of miltefosine against Trypanosoma cruzi

GULIN, JULIÁN ERNESTO NICOLÁS; ALTCHEH, J; BISIO, M; ROCCO, DM; SOLANA, ME; GARCÍA BOURNISSEN, F

Atlanta, Georgia

Encuentro; 65th Annual Meeting.; 2016

American Society of Tropical Medicine and Hygiene

Chagas disease treatment options are limited to Benznidazole (BZ) and Nifurtimox (NFX). These drugs have high efficacy in acute phase but its use in chronic phases is still under debate, and severe adverse effects are frequent. Alternative treatments are not currently available, in part due to high cost of developing new effective molecules. Drug repurposing is a cost-effective potential solution to fulfill current needs of better and safer therapy for Chagas disease. In primary screening at 10 µM, we found that Miltefosine (MLT; a phosphatidylcholine analog with antineoplastic and anti?Leishmania activity) exhibited higher relative anti-T cruzi activity (%RA) against trypomastigotes of T. cruzi VD strain compared to BZ and NFX, and equal %RA against amastigotes. Consequently, MLT was moved to secondary screening, obtaining a dose-response curve with lytic concentration 50% (LC50) of 14.25 µM (CI95%: 8.23; 24.67) on trypomastigotes and inhibitory concentration 50% (IC50) of 1.44 (CI95%: 0.634; 1.716) µM on amastigotes. These results supported further evaluation in an acute murine model of T. cruzi infection. Experimental protocol was approved by Faculty of Veterinary Sciences (UBA) (IACUC#2014/4). BALB/c females were infected with 500 trypomastigotes by intraperitoneal (ip) route and treated orally after 8 days of infection with MLT at 25, 50, 75 or 100 mg/kg for 20 consecutive days. Infected non-treated (NT) and BZ or NFX treated groups (100 mg/kg) were included. MLT treatment decreased parasitemia levels in a dose-response manner, with 100% of survival in mice from 50 to 100 mg/kg dosing. Mice with negative parasitemia were subjected to an immunosuppression cycle (cyclophosphamide 200 mg/kg, ip, 1/week, up to four weeks). Parasitemia reactivation was recorded in 100% of mice in all MLT treated groups, as well as in all mice from BZ group, and in 57% of animals from NFX group. MLT exhibited an excellent in vitro parasiticidal effect, especially against amastigotes, but parasitostatic activity in vivo. Further studies on combined therapies with BZ or NFX and the evaluation of other repurposed candidates are needed and currently performed.