Combination therapy for visceral leishmaniasis.

Combination therapy for the treatment of visceral leishmaniasis has increasingly been advocated as a way to increase treatment efficacy and tolerance, reduce treatment duration and cost, and limit the emergence of drug resistance. We reviewed the evidence and potential for combination therapy, and the criteria for the choice of drugs in such regimens. The first phase 2 results of combination regimens are promising, and have identified effective and safe regimens as short as 8 days. Several phase 3 trials are underway or planned in the Indian subcontinent and east Africa. The limited data available suggest that combination therapy is more cost-effective and reduces indirect costs for patients. Additional advantages are reduced treatment duration (8-17 days), with potentially better patient compliance and lesser burden on the health system. Only limited data are available on how best to prevent acquired resistance. Patients who are coinfected with visceral leishmaniasis and HIV could be a reservoir for development and spread of drug-resistant strains, calling for special precautions. The identification of a short, cheap, well-tolerated combination regimen that can be given in ambulatory care and needs minimal clinical monitoring will most likely have important public health implications. Effective monitoring systems and close regulations and policy will be needed to ensure effective implementation. Whether combination therapy could indeed help delay resistance, and how this is best achieved, will only be known in the long term.