Reply to Arya and Agarwal

TO THE EDITOR—We recognize and share the concerns expressed by Arya and Agarwal on the issue of drug quality in the treatment of visceral leishmaniasis (VL) [1], but dismiss this as a possible explanation for the observed high relapse rate in our study and, more generally, we favor a different approach to cope with this issue. As Arya and Agarwal accurately point out, we have previously described the first case of a " substandard " miltefosine medicine from Bangladesh that did not contain any of its active ingredient, milte-fosine [2]. This product was manufactured locally for the Bangladeshi elimination program for VL, but has been replaced now in Bangladesh by the originator product Impavido manufactured by Paladin Labs. The product that was and is being used in the Nepali VL elimination program , and thus was used throughout the reported cohort study, is the same quality-controlled originator product by Paladin Labs. Moreover, following our clinical finding of increased relapse rates in miltefosine-treated Nepali VL patients, we performed additional quality checks using liquid chromatography coupled to tandem mass spectrometry on the batch of miltefosine capsules used by the patients in our study, which confirmed that these capsules contained the exact declared amount of miltefosine. This is further corroborated by representable pharmacokinetic profiles of miltefosine in our patients, as illustrated in our publication [3]. All in all, the increase in relapse rates for VL in Nepal as reported