The status of combination therapy for visceral leishmaniasis: an updated review.

For the past 15 years, trials of combination therapy options for visceral leishmaniasis have been conducted with the aim of identifying effective, and safe treatment regimens that were shorter than existing monotherapy regimens and could also prevent or delay the emergence of drug resistance. Although first-line treatment currently relies on combination therapy in east Africa, this is not true in Latin America owing to disappointing trial results, with lower than expected efficacy seen for the combination treatment group. By contrast, several effective combination therapy regimens have been identified through trials on the Indian subcontinent; yet, first-line therapy is still AmBisome monotherapy as the drug is part of a free donation programme and is highly effective in this region. Achieving a short all-oral combination treatment will require new chemical entities, several of which are currently under evaluation. Future studies should systematically include pharmacological substudies to ensure optimal dosing for all patient groups. To achieve maximal impact of new combination treatments, mechanisms to ensure drug availability and access after trials should be established. Enhancing the longevity of current and novel treatments will require effective systems for early detection of emerging drug resistance.