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Introduction: Intramuscular paromomycin monotherapy to treat visceral leishmaniasis (VL) has been shown to be effective for Indian patients, while a similar regimen resulted in lower efficacy in Eastern Africa, which could be related to differences in paromomycin pharmacokinetics. Methods: Pharmacokinetic data were available from two randomized controlled trials in VL patients from Eastern Africa and India. African patients received intramuscular paromomycin monotherapy (20 mg/kg for 21 days) or combination therapy (15 mg/kg for 17 days) with sodium stibogluconate. Indian patients received paromomycin monotherapy (15 mg/kg for 21 days). A population pharmacokinetic model was developed for paromomycin in Eastern African and Indian VL patients. Results: Seventy-four African patients (388 observations) and 528 Indian patients (1321 observations) were included in this pharmacokinetic analysis. A one-compartment model with first-order kinetics of absorption and elimination best described paromomycin in plasma. Bioavailability (relative standard error) was 1.17 (5.18%) times higher in Kenyan and Sudanese patients, and 2.46 (24.5%) times higher in Ethiopian patients, compared with Indian patients. Ethiopian patients had an approximately fourfold slower absorption rate constant of 0.446 h–1 (18.2%). Area under the plasma concentration-time curve for 24 h at steady-state (AUCτ,SS) for 15 mg/kg/day (median [interquartile range]) was higher in Kenya and Sudan (172.7 µg·h/mL [145.9–214.3]) and Ethiopia (230.1 µg·h/mL [146.3–591.2]) compared with India (97.26 µg·h/mL [80.83–123.4]). Conclusion: The developed model provides detailed insight into the pharmacokinetic differences among Eastern African countries and India, however the resulting differences in paromomycin exposure do not seem to explain the geographical differences in paromomycin efficacy in the treatment of VL patients. [ABSTRACT FROM AUTHOR]

Background To expedite the development of new oral treatment regimens for visceral leishmaniasis (VL), there is a need for early markers to evaluate treatment response and predict long-term outcomes. Methods Data from 3 clinical trials were combined in this study, in which Eastern African VL patients received various antileishmanial therapies. Leishmania kinetoplast DNA was quantified in whole blood with real-time quantitative polymerase chain reaction (qPCR) before, during, and up to 6 months after treatment. The predictive performance of pharmacodynamic parameters for clinical relapse was evaluated using receiver-operating characteristic curves. Clinical trial simulations were performed to determine the power associated with the use of blood parasite load as a surrogate endpoint to predict clinical outcome at 6 months. Results The absolute parasite density on day 56 after start of treatment was found to be a highly sensitive predictor of relapse within 6 months of follow-up at a cutoff of 20 parasites/mL (area under the curve 0.92, specificity 0.91, sensitivity 0.89). Blood parasite loads correlated well with tissue parasite loads (ρ = 0.80) and with microscopy gradings of bone marrow and spleen aspirate smears. Clinical trial simulations indicated a > 80% power to detect a difference in cure rate between treatment regimens if this difference was high (> 50%) and when minimally 30 patients were included per regimen. Conclusions Blood Leishmania parasite load determined by qPCR is a promising early biomarker to predict relapse in VL patients. Once optimized, it might be useful in dose finding studies of new chemical entities. [ABSTRACT FROM AUTHOR]

Abstract Background Treatment options for Visceral Leishmaniasis (VL) in East Africa are far from satisfactory due to cost, toxicity, prolonged treatment duration or emergence of parasite resistance. Hence there is a need to explore alternative treatment protocols such as miltefosine alone or in combinations including miltefosine, sodium stibogluconate (SSG) or liposomal amphotericin B. The aim of this trial is to identify regimen(s) which are sufficiently promising for future trials in East Africa. Methods/Design A phase II randomized, parallel arm, open-labelled trial is being conducted to assess the efficacy of each of the three regimens: liposomal amphotericin B with SSG, Liposomal amphotericin B with miltefosine and miltefosine alone. The primary endpoint is cure at day 28 with secondary endpoint at day 210 (6 months). Initial cure is a single composite measure based on parasitologic evaluation (bone marrow, spleen or lymph node aspirate) and clinical assessment. Repeated interim analyses have been planned after recruitment of 15 patients in each arm with a maximum sample size of 63 for each. These will follow group-sequential methods (the triangular test) to identify when a regimen is inadequate (90% efficacy). We describe a method to ensure consistency of the sequential analysis of day 28 cure with the non-sequential analysis of day 210 cure. Discussion A regimen with adequate efficacy would be a candidate for treatment of VL with reasonable costs. The design allows repeated testing throughout the trial recruitment period while maintaining good statistical properties (Type I & II error rates) and reducing the expected sample sizes. Trial Registration ClinicalTrials.gov: NCT01067443

Background: Low efficacy of miltefosine in the treatment of visceral leishmaniasis was recently observed in Eastern Africa.Objectives: To describe the pharmacokinetics and establish a pharmacokinetic/pharmacodynamic relationship for miltefosine in Eastern African patients with visceral leishmaniasis, using a time-to-event approach to model relapse of disease.Methods: Miltefosine plasma concentrations from 95 patients (48 monotherapy versus 47 combination therapy) were included in the population pharmacokinetic model using non-linear mixed effects modelling. Subsequently a time-to-event model was developed to model the time of clinical relapse. Various summary pharmacokinetic parameters (various AUCs, Time > EC50, Time > EC90), normalized within each treatment arm to allow simultaneous analysis, were evaluated as relapse hazard-changing covariates.Results: A two-compartment population model with first-order absorption fitted the miltefosine pharmacokinetic data adequately. Relative bioavailability was reduced (-74%, relative standard error 4.7%) during the first week of treatment of the monotherapy arm but only the first day of the shorter combination regimen. Time to the relapse of infection could be described using a constant baseline hazard (baseline 1.8 relapses/year, relative standard error 72.7%). Miltefosine Time > EC90 improved the model significantly when added in a maximum effect function on the baseline hazard (half maximal effect with Time > EC90 6.97 days for monotherapy).Conclusions: Miltefosine drug exposure was found to be decreased in Eastern African patients with visceral leishmaniasis, due to a (transient) initial lower bioavailability. Relapse hazard was inversely linked to miltefosine exposure. Significantly lower miltefosine exposure was observed in children compared with adults, further urging the need for implementation of dose adaptations for children. [ABSTRACT FROM AUTHOR]

Background: Anti-leishmanial drug regimens that include a single dose AmBisome® could be suitable for eastern African patients with symptomatic visceral leishmaniasis (VL) but the appropriate single dose is unknown. Methodology: A multi-centre, open-label, non-inferiority, randomized controlled trial with an adaptive design, was conducted to compare the efficacy and safety of a single dose and multiple doses of AmBisome® for the treatment of VL in eastern Africa. The primary efficacy endpoint was definitive cure (DC) at 6 months. Symptomatic patients with parasitologically-confirmed, non-severe VL, received a single dose of AmBisome® 7.5 mg/kg body weight or multiple doses, 7 times 3 mg/kg on days 1–5, 14, and 21. If interim analyses, evaluated 30 days after the start of treatment following 40 or 80 patients, showed the single dose gave significantly poorer parasite clearance than multiple doses at the 5% significance level, the single dose was increased by 2·5 mg/kg. In a sub-set of patients, parasite clearance was measured by quantitative reverse transcriptase (qRT) PCR. Principal Findings: The trial was terminated after the third interim analysis because of low efficacy of both regimens. Based on the intention-to-treat population, DC was 85% (95%CI 73–93%), 40% (95%CI 19–64%), and 58% (95%CI 41–73%) in patients treated with multiple doses (n = 63), and single doses of 7·5 (n = 21) or 10 mg/kg (n = 40), respectively. qRT-PCR suggested superior parasite clearance with multiple doses as early as day 3. Safety data accorded with the drug label. Conclusions: The tested AmBisome® regimens would not be suitable for VL treatment across eastern Africa. An optimal single dose regimen was not identified. Trials Registration: www.clinicaltrials.govNCT00832208 Author Summary: Visceral leishmaniasis is a potentially fatal disease which affects 0.2–0.4 million people every year, principally in South-East Asia, Latin America or Eastern Africa. Currently the safest drug in use is AmBisome®, which cures 90% of patients in India at 5 mg/kg, and is even more effective at higher doses (10 mg/kg) or in combination with miltefosine or paromomycin. These regimens have been shown to be equally cost-effective in India. However, the drug requires a cold chain for storage and reconstitution prior to injection. Although it is licensed for use in eastern Africa, in practice it is mainly used as a second-line treatment. A small study carried out in Kenya indicated that a higher dose is necessary in eastern Africa in contrast to Asia. This study aimed to determine the minimum single dose that is safe and effective for treatment of eastern African VL patients so as to be used in simplified treatment regimens. However, the tested regimens were found to be ineffective, and an optimal single dose that could potentially be used in simplified treatment regimens was not identified. [ABSTRACT FROM AUTHOR]

Background: Treatment options for visceral leishmaniasis (VL) in East Africa are far from satisfactory due to cost, toxicity, prolonged treatment duration or emergence of parasite resistance. Hence there is a need to explore alternative treatment protocols such as miltefosine alone or in combinations including miltefosine, sodium stibogluconate (SSG) or liposomal amphotericin B. The aim of this trial is to identify regimen(s) which are sufficiently promising for future trials in East Africa.Methods/design: A phase II randomized, parallel arm, open-labelled trial is being conducted to assess the efficacy of each of the three regimens: liposomal amphotericin B with SSG, Liposomal amphotericin B with miltefosine and miltefosine alone. The primary endpoint is cure at day 28 with secondary endpoint at day 210 (6 months). Initial cure is a single composite measure based on parasitologic evaluation (bone marrow, spleen or lymph node aspirate) and clinical assessment. Repeated interim analyses have been planned after recruitment of 15 patients in each arm with a maximum sample size of 63 for each. These will follow group-sequential methods (the triangular test) to identify when a regimen is inadequate (<75% efficacy) or adequate (>90% efficacy). We describe a method to ensure consistency of the sequential analysis of day 28 cure with the non-sequential analysis of day 210 cure.Discussion: A regimen with adequate efficacy would be a candidate for treatment of VL with reasonable costs. The design allows repeated testing throughout the trial recruitment period while maintaining good statistical properties (Type I & II error rates) and reducing the expected sample sizes.Trial Registration: ClinicalTrials.gov: NCT01067443. [ABSTRACT FROM AUTHOR]