Status: The goal of this project is to identify an improved formulation of amphotericin B that shows the most promise in terms of in vivo efficacy, safety, heat stability, and cost. Amphotericin B, under various formulations, is one of the most efficacious treatments for VL. The standard formulations (oily suspension) have side effects. AmBisome®, a liposomal formulation, has overcome these limitations, but its high cost and lack of heat stability limit its utility in disease-endemic countries. Recently, new formulations have emerged and have either been approved or are under clinical development in India. However, they are still not field-adapted and there is no safety and VL efficacy data available yet. DNDi and its UK partners are investigating improved polymer-based formulations to replace the lipid-based component with a narrow molecular weight range polymer. Ideally, the selected polymer can form an amphotericin B conjugate that is soluble, cheaper, better tolerated, and has increased thermal stability. Initial results show that reproducible in vivo activity could be achieved without signs of amphotericin-induced toxicity in test animals. Further characterization is in progress.