Detection of Leishmania Antigen from Buccal Swabs in Kala-azar Patients Using KATEX Method

Background: Visceral leishmaniasis (VL) or kala-azar is a chronic protozoan infection in humans that is fatal unless treated and is associated with significant global morbidity and mortality. Confirmation of visceral leishmaniasis (VL) diagnosis requires microscopic examination to visualize the causative agent Leishmania Donovani usually in spleen or bone marrow aspirate. Tissue aspiration is invasive, potentially risky and require skilled personnel. KATEX (Kalon biologicals) antigen test for VL in buccal swabs has not been evaluated locally and could offer a significant advantage in screening patients suspected of VL.  Method: A cross sectional study was conducted after receiving approval from KEMRI SERU. We obtained buccal swabs from patients presenting at Kimalel Health Centre, Baringo County, Kenya from VL cases and controls. VL was defined as patients meeting VL case definition with positive splenic aspirate microscopy while endemic controls were defined as patients presenting to the health center with no fever and no prior history of Kala azar but living in VL endemic. Latex agglutination based test (KATEX) was used to detect parasite antigen in buccal swabs. It was a proof of principle study carried out to explore the ability to use KATEX, a simple non-invasive diagnostic test to detect leishmania antigens in buccal swabs, determine the ability of the kit to detect leishmania antigens in buccal cells of kala-azar patients and compare the sensitivity and specificity of KATEX - buccal assay using microscopy as the gold standard. Results: 88 patients were analyzed, including 44 VL and 44 non-VL patients. The median age of VL patients was 18 years with predominance of males (68.2%). None of the tested VL patients were co-infected with HIV. KATEX kit was able to detect visceral leishmaniasis antigens from the buccal swabs giving a sensitivity of (81.8%; 95%CI: 67.3% to 91.8%, specificity of (79.5%; 95%CI: 64.7 –90.2%), Positive predictive value n= 36(80.0%); 95%CI: 65.4% to 90.4% and Negative predictive values n = 35(81.4%); 95% CI: 66.6% to 91.6%. Conclusion and Recommendation: Buccal swab test assay using KATEX is an easy test to perform and promising non-invasive based antigen detection test which may be useful for screening kala-azar patients and could be applied in the diagnosis of VL. It is a functional assay that warrants a larger study with a larger sample size for the purpose of evaluating the utility of the test in diagnosing visceral leishmaniasis. There is dire need to identify non-invasive, less risky and field adapted point of care diagnostics for VL. Keywords: Kala-azar; Visceral Leishmaniasis; Diagnosis; KATEX; Latex; Buccal swab antigen detection

Paromomycin for the Treatment of Visceral Leishmaniasis in Sudan: A Randomized, Open-Label, Dose-Finding Study

Visceral leishmaniasis (VL) is a parasitic disease transmitted through the bite of sandflies. The WHO estimates 500,000 new cases of VL each year, with more than 90% of cases occurring in Southeast Asia, East Africa, and South America. If left untreated, VL can be fatal. We had previously conducted a large multi-center study in Sudan, East Africa, to assess the efficacy of paromomycin (PM) alone or in combination with sodium stibogluconate. Clinical studies in India have shown that 15 mg/kg/day PM for 21 days was an effective cure. However, the same treatment regimen was not efficacious in two study sites in Sudan. Here, our aim was to assess two high-dose regimens of PM in Sudan: 15 mg/kg/day for 28 days and 20 mg/kg/day for 21 days. The results suggest that, at these total doses, PM is more efficacious than when given daily at 15 mg/kg for 21 days, and that high doses are required to treat VL in Sudan. Efficacy of 20 mg/kg/day PM for 21 days is currently being evaluated in a prospective, comparative phase III trial in East Africa

Safety and Efficacy of miltefosine alone and in combination with sodium stibogluconate and liposomal amphotericin B for the treatment of primary visceral leishmaniasis in East Africa: study protocol for a randomized controlled trial

<p>Abstract</p> <p>Background</p> <p>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.</p> <p>Methods/Design</p> <p>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.</p> <p>Discussion</p> <p>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.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov: <a href="http://www.clinicaltrials.gov/ct2/show/NCT01067443">NCT01067443</a></p

Blood Parasite Load as an Early Marker to Predict Treatment Response in Visceral Leishmaniasis in Eastern Africa

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.This work was supported by the European Union Seventh Framework Programme Africoleish (grant number 305178); the World Health Organization—Special Programme for Research and Training in Tropical Diseases (WHO-TDR); the French Development Agency, France (grant number CZZ2062); UK aid, UK; the Federal Ministry of Education and Research through KfW, Germany; the Medicor Foundation, Liechtenstein; Médecins Sans Frontières, International; the Swiss Agency for Development and Cooperation (SDC), Switzerland (grant number 81017718); the Dutch Ministry of Foreign Affairs (DGIS), the Netherlands (grant number PDP15CH21); the French Ministry for Europe and Foreign Affairs (MEAE), France; The Rockefeller Foundation, USA; BBVA Foundation, Spain; the European Union—AfriKADIA project of the Second European and Developing Countries Clinical Trials Partnership Programme (EDCTP2) (grant number RIA2016S1635); and ZonMw/Dutch Research Council (NWO) Veni grant (project number 91617140 to T. P. C. D.).S

Visceral Leishmaniasis: New Health Tools Are Needed

Half a million new cases of visceral leishmaniasis occur each year, and 10% of these are fatal. New tools are urgently needed for mapping, diagnosing, and treating the disease

Validation of Two Rapid Diagnostic Tests for Visceral Leishmaniasis in Kenya

BACKGROUND: Visceral leishmaniasis (VL) is a systemic parasitic disease that is fatal unless treated. In Kenya, national VL guidelines rely on microscopic examination of spleen aspirate to confirm diagnosis. As this procedure is invasive, it cannot be safely implemented in peripheral health structures, where non-invasive, accurate, easy to use diagnostic tests are needed. METHODOLOGY: We evaluated the sensitivity, specificity and predictive values of two rapid diagnostic tests (RDT), DiaMed IT LEISH and Signal-KA, among consecutive patients with clinical suspicion of VL in two treatment centres located in Baringo and North Pokot District, Rift Valley province, Kenya. Microscopic examination of spleen aspirate was the reference diagnostic standard. Patients were prospectively recruited between May 2010 and July 2011. PRINCIPAL FINDINGS: Of 251 eligible patients, 219 patients were analyzed, including 131 VL and 88 non-VL patients. The median age of VL patients was 16 years with predominance of males (66%). None of the tested VL patients were co-infected with HIV. Sensitivity and specificity of the DiaMed IT LEISH were 89.3% (95%CI: 82.7-94%) and 89.8% (95%CI: 81.5-95.2%), respectively. The Signal KA showed trends towards lower sensitivity (77.1%; 95%CI: 68.9-84%) and higher specificity (95.5%; 95%CI: 88.7-98.7%). Combining the tests did not improve the overall diagnostic performance, as all patients with a positive Signal KA were also positive with the DiaMed IT LEISH. CONCLUSION/SIGNIFICANCE: The DiaMed IT LEISH can be used to diagnose VL in Kenyan peripheral health facilities where microscopic examination of spleen aspirate or sophisticated serological techniques are not feasible. There is a crucial need for an improved RDT for VL diagnosis in East Africa

Population pharmacokinetics of a combination of miltefosine and paromomycin in Eastern African children and adults with visceral leishmaniasis

Objectives: To improve visceral leishmaniasis (VL) treatment in Eastern Africa, 14-and 28-day combination regimens of paromomycin plus allometrically dosed miltefosine were evaluated. As the majority of patients affected by VL are children, adequate paediatric exposure to miltefosine and paromomycin is key to ensuring good treatment response. Methods: Pharmacokinetic data were collected in a multicentre randomized controlled trial in VL patients from Kenya, Sudan, Ethiopia and Uganda. Patients received paromomycin (20 mg/kg/day for 14 days) plus miltefosine (allometric dose for 14 or 28 days). Population pharmacokinetic models were developed. Adequacy of exposure and target attainment of paromomycin and miltefosine were evaluated in children and adults. Results: Data from 265 patients (59% ≤12 years) were available for this pharmacokinetic analysis. Paromomycin exposure was lower in paediatric patients compared with adults [median (IQR) end-of-Treatment AUC0-24h 187 (162-203) and 242 (217-328) μg·h/mL, respectively], but were both within the IQR of end-of-Treatment exposure in Kenyan and Sudanese adult patients from a previous study. Cumulative miltefosine end-of-Treatment exposure in paediatric patients and adults [AUCD0-28 517 (464-552) and 524 (456-567) μg·day/mL, respectively] and target attainment [time above the in vitro susceptibility value EC90 27 (25-28) and 30 (28-32) days, respectively] were comparable to previously observed values in adults. Conclusions: Paromomycin and miltefosine exposure in this new combination regimen corresponded to the desirable levels of exposure, supporting the implementation of the shortened 14 day combination regimen. Moreover, the lack of a clear exposure-response and exposure-Toxicity relationship indicated adequate exposure within the therapeutic range in the studied population, including paediatric patients

Single-dose liposomal amphotericin B (AmBisome®) for the treatment of Visceral Leishmaniasis in East Africa: study protocol for a randomized controlled trial

BACKGROUND: AmBisome® is an efficacious, safe anti-leishmanial treatment. There is growing interest in its use, either as a single dose or in combination treatments. In East Africa, the minimum optimal single-dosage has not been identified. METHODS/DESIGN: An open-label, 2-arm, non-inferiority, multi-centre randomised controlled trial is being conducted to determine the optimal single-dose treatment with AmBisome®.Patients in the single-dose arm will receive one infusion on day 1, at a dose depending on body weight. For the first group of patients entered to the trial, the dose will be 7.5 mg/kg, but if this dose is found to be ineffective then in subsequent patient series the dose will be escalated progressively to 10, 12.5 and 15 mg/kg. Patients in the reference arm will receive a multi-dose regimen of AmBisome® (3 mg/kg/day on days 1-5, 14 and 21: total dose 21 mg/kg). Patients will be hospitalised for approximately one month after the start of treatment and then followed up at three and six months. The primary endpoint is the status of patients six months after treatment. A secondary endpoint is assessment at day 30. Treatment success is determined as the absence of parasites on microscopy samples taken from bone marrow, lymph node or splenic aspirates. Interim analyses to assess the comparative efficacy of the single dose are planned after recruitment of 20 and 40 patients per arm. The final non-inferiority analysis will include 120 patients per arm, to determine if the single-dose efficacy 6 months after treatment is not more than 10% inferior to the multi-dose. DISCUSSION: An effective, safe single-dose treatment would reduce hospitalization and treatment costs. Results will inform the design of combination treatment studies. TRIAL REGISTRATION: ClinicalTrials.gov NCT00832208

Long term outcomes and prognostics of visceral leishmaniasis in HIV infected patients with use of pentamidine as secondary prophylaxis based on CD4 level: a prospective cohort study in Ethiopia.

BACKGROUND: The long-term treatment outcome of visceral leishmaniasis (VL) patients with HIV co-infection is complicated by a high rate of relapse, especially when the CD4 count is low. Although use of secondary prophylaxis is recommended, it is not routinely practiced and data on its effectiveness and safety are limited. METHODS: A prospective cohort study was conducted in Northwest Ethiopia from August 2014 to August 2017 (NCT02011958). HIV-VL patients were followed for up to 12 months. Patients with CD4 cell counts below 200/μL at the end of VL treatment received pentamidine prophylaxis starting one month after parasitological cure, while those with CD4 count ≥200 cells/μL were followed without secondary prophylaxis. Compliance, safety and relapse-free survival, using Kaplan-Meier analysis methods to account for variable time at risk, were summarised. Risk factors for relapse or death were analysed. RESULTS: Fifty-four HIV patients were followed. The probability of relapse-free survival at one year was 50% (95% confidence interval [CI]: 35-63%): 53% (30-71%) in 22 patients with CD4 ≥200 cells/μL without pentamidine prophylaxis and 46% (26-63%) in 29 with CD4 <200 cells/μL who started pentamidine. Three patients with CD4 <200 cells/μL did not start pentamidine. Amongst those with CD4 ≥200 cells/μL, VL relapse was an independent risk factor for subsequent relapse or death (adjusted rate ratio: 5.42, 95% CI: 1.1-25.8). Except for one case of renal failure which was considered possibly related to pentamidine, there were no drug-related safety concerns. CONCLUSION: The relapse-free survival rate for VL patients with HIV was low. Relapse-free survival of patients with CD4 count <200cells/μL given pentamidine secondary prophylaxis appeared to be comparable to patients with a CD4 count ≥200 cells/μL not given prophylaxis. Patients with relapsed VL are at higher risk for subsequent relapse and should be considered a priority for secondary prophylaxis, irrespective of their CD4 count