Drug policy for visceral leishmaniasis: a cost-effectiveness analysis

Vaccine value profile for leishmaniasis

Leishmania infections are global, occurring in 98 countries and all World Health Organization (WHO) regions with 600 million to 1 billion people at risk of infection. Visceral leishmaniasis is associated with almost 20,000 reported deaths annually, with children under 5 years of age being at the greatest risk of mortality. Amongst WHO-recognised Neglected Tropical Diseases (NTDs), leishmaniasis is one of the most important in terms of mortality and morbidity. With an increasing global burden of disease and a growing threat from climate change, urbanisation and drug resistance, there remains an imperative to develop leishmaniasis vaccines. New tools to understand correlates of protection and to assess vaccine efficacy are being developed to ease the transition into larger scale efficacy trials or provide alternate routes to licensure. Early indications suggest a diverse portfolio of manufacturers exists in endemic countries with an appetite to develop leishmaniasis vaccines. This Vaccine Value Profile (VVP) provides a high-level, comprehensive assessment of the currently available data to inform the potential public health, economic, and societal value of leishmaniasis vaccines. The leishmaniasis VVP was developed by a working group of subject matter experts from academia, public health groups, policy organizations, and non-profit organizations. All contributors have extensive expertise on various elements of the leishmaniasis VVP and have collectively described the state of knowledge and identified the current gaps. The VVP was developed using only existing and publicly available information.

Comparative analysis of the transcriptional responses of five Leishmania species to trivalent antimony

BACKGROUND

Leishmaniasis is a neglected tropical disease caused by several species of Leishmania. The resistance phenotype of these parasites depends on the characteristics of each species, which contributes to increased therapeutic failures. Understanding the mechanism used by the parasite to survive under treatment pressure in order to identify potential common and specific therapeutic targets is essential for the control of leishmaniasis. The aim of this study was to investigate the expression profiles and potential shared and specific resistance markers of the main Leishmania species of medical importance [subgenus L. (Leishmania): L. donovani, L. infantum and L. amazonensis; subgenus L. (Viannia): L. panamensis and L. braziliensis)] resistant and sensitive to trivalent stibogluconate (SbIII).

METHODS

We conducted comparative analysis of the transcriptomic profiles (only coding sequences) of lines with experimentally induced resistance to SbIII from biological replicates of five Leishmania species available in the databases of four articles based on ortholog attribution. Simultaneously, we carried out functional analysis of ontology and reconstruction of metabolic pathways of the resulting differentially expressed genes (DEGs).

RESULTS

Resistant lines for each species had differential responses in metabolic processes, compound binding, and membrane components concerning their sensitive counterpart. One hundred and thirty-nine metabolic pathways were found, with the three main pathways comprising cysteine and methionine metabolism, glycolysis, and the ribosome. Differentially expressed orthologous genes assigned to species-specific responses predominated, with 899 self-genes. No differentially expressed genes were found in common among the five species. Two common upregulated orthologous genes were found among four species (L. donovani, L. braziliensis, L. amazonensis, and L. panamensis) related to an RNA-binding protein and the NAD(P)H cytochrome-B5-oxidoreductase complex, associated with transcriptional control and de novo synthesis of linoleic acid, critical mechanisms in resistance to antimonials.

CONCLUSION

Herein, we identified potential species-specific genes related to resistance to SbIII. Therefore, we suggest that future studies consider a treatment scheme that is species-specific. Despite the limitations of our study, this is the first approach toward unraveling the pan-genus genetic mechanisms of resistance in leishmaniasis.

Economic evaluations addressing diagnosis and treatment strategies for neglected tropical diseases: an overview

Neglected tropical diseases (NTDs) are those affecting vulnerable people and causing additional social and economic burden. The aim of this study was to carry out a general overview of the health economic assessments involving the diagnosis and treatment of six NTDs: cutaneous leishmaniasis (CL), Chagas disease, cysticercosis, filariasis, schistosomiasis and visceral leishmaniasis (VL). The literature search was based on two of the main medical literature databases (Medline and SciELO) and identified 46 studies. Twenty-six studies (57%) addressed therapeutic strategies, while other 20 (43%) assessed diagnostic or both diagnostic and therapeutic approaches. The studies were published between 1994 and 2021, and 57% of them (26/46) were carried out in four countries. Cost-effectiveness analyses were conducted in 59% (27/46) of the studies. Economic studies of NTDs have timidly increased in recent years. Despite the improvement of analytical methods, completeness and accuracy of information, there are few new technologies applied to NTDs and public health systems. In addition, economic studies for NTDs are concentrated in a few countries. Thus, this review points out the need for investment in research, development and training of human resources dedicated to the economic analysis in health, especially on NTDs, as a strategy to reduce inequalities by optimizing the use of health resources.

Cost-effectiveness analysis of Mucosal Leishmaniasis diagnosis with PCR-based vs parasitological tests in Colombia

To estimate the cost-effectiveness of available diagnosis alternatives for Mucosal Leishmaniasis (ML) in Colombian suspected patients. A simulation model of the disease's natural history was built with a decision tree and Markov models. The model´s parameters were identified by systematic review and validated by expert consensus. A bottom-up cost analysis to estimate the costs of diagnostic strategies and treatment per case was performed by reviewing 48 clinical records of patients diagnosed with ML. The diagnostic strategies compared were as follows: 1) no diagnosis; 2) parasite culture, biopsy, indirect immunofluorescence assay (IFA), and Montenegro skin test (MST) combined ; 3) parasite culture, biopsy, and IFA combined; 4) PCR-miniexon; and 5) PCR-kDNA. Three scenarios were modeled in patients with ML clinical suspicion, according to ML prevalence scenarios: high, medium and low. Adjusted sensitivity and specificity parameters of a combination of diagnostic tests were estimated with a discrete event simulation (DES) model. For each alternative, the costs and health outcomes were estimated. The time horizon was life expectancy, considering the average age at diagnosis of 31 years. Incremental cost-effectiveness ratios (ICERs) were calculated per Disability Life Year (DALY) avoided, and deterministic and probabilistic sensitivity analyses were performed. A threshold of willingness to pay (WTP) of three-time gross domestic product per capita (GDPpc) (US$ 15,795) and a discount rate of 3% was considered. The analysis perspective was the third payer (Health System). All costs were reported in American dollars as of 2015. PCR- kDNA was the cost-effective alternative in clinical suspicion levels: low, medium and high with ICERs of US$ 7,909.39, US$ 5,559.33 and US$ 4,458.92 per DALY avoided, respectively. ML diagnostic tests based on PCR are cost-effective strategies, regardless of the level of clinical suspicion. PCR-kDNA was the most cost-effective strategy in the competitive scenario with the parameters included in the present model.

Treatment for human visceral leishmaniasis: a cost-effectiveness analysis for Brazil

OBJECTIVE

To estimate the cost-effectiveness of strategies for the treatment of VL in Brazil.

METHODS

Cost-effectiveness study comparing three therapeutic options: meglumine antimoniate (MA), liposomal amphotericin B (LAMB) and a combination of LAMB plus MA (LAMB plus MA), from public health system and societal perspectives. An analytical decision-making model was used to compare strategies for the following outcomes: early therapeutic failure avoided at 30 days, days of hospitalisation avoided and VL cure at 180 days. The efficacy and safety parameters of the drugs came from a randomised, open-label trial and the cost data came from a cost-of-illness study, both carried out in Brazil.

RESULTS

For all outcomes analysed, the LAMB strategy was more effective. The MA strategy was inferior to the LAMB plus MA strategy for the outcomes early therapeutic failure avoided and cure. When only LAMB and MA were compared from a societal perspective, a cost of US$ 278.56 was estimated for each additional early therapeutic failure avoided, a cost of US$ 26.88 for each additional day of hospitalisation avoided and a cost of US$ 89.88 for each additional case of cured VL, for the LAMB strategy vs. MA.

CONCLUSION

In Brazil, the LAMB strategy proved to be cost-effective for treating VL, considering a GDP per capita as the willingness-to-pay threshold, for all of the outcomes analysed in comparison to MA.

Eligibility for Local Therapies in Adolescents and Adults with Cutaneous Leishmaniasis from Southwestern Colombia: A Cross-Sectional Study

Local therapies have been proposed as safe and effective alternatives to systemic drugs in cutaneous leishmaniasis (CL), especially among less severe cases. However, they are not widely available and used in endemic places, including Colombia, which has a high burden of disease. Further complicating the uptake of local therapies is that different treatment guidelines have been established by the World Health Organization (WHO) and Pan American Health Organization (PAHO). Using data from a large referral center in Colombia, we determined the proportion of patients who would be eligible for and potentially benefit from local therapies according to both international guidelines. The sample included 1,891 confirmed cases of CL aged ≥ 12 years, mostly infected with Leishmania Viannia panamensis (91%, n = 601/660), between 2004 and 2014. Overall, 57% of the sample had one lesion, whereas another 31% had two to three lesions. For 74% of patients, all lesions were in an area other than head or neck. The maximum lesion size was ≤ 3 cm for 58% and < 5 cm for 88% of the sample. Based on our data, up to 56% of patients could have been eligible for local therapies according to the WHO criteria. By contrast, only 23% were eligible according to the more restrictive PAHO criteria. Regardless, these data suggest that a substantial proportion of CL patients in Colombia may benefit from local therapies given their relatively mild presentation of disease and low risk of complications. Individualized risk-benefit assessment and guideline adjustments may increase local therapy eligibility and benefit a large number of patients.

Amphotericin B deoxycholate for relapse visceral leishmaniasis in Bangladesh: a cross-sectional study

Objective

Based on studies in India (as there was no studies from outside India) amphotericin B deoxycholate has been considered as a backup drug for treatment of visceral leishmaniasis. However, treatment response and adverse effect to anti-leishmanial drugs may vary across different populations and in Bangladesh the effect to amphotericin B deoxycholate for treatment of visceral leishmaniasis is still unknown. Therefore, there is a need to explore cure rate and adverse effects to amphotericin B deoxycholate to justify its use on visceral leishmaniasis patients in Bangladesh.

Result

Here we report 34 visceral leishmaniasis patients who received treatment with amphotericin B deoxycholate in the Surya Kanta Kala-azar Research Centre from December 2011 to June 2015. The dose of the treatment was 1 mg/kg body weight for 15 days followed up until 12 months after treatment. Response to amphotericin B deoxycholate treatment was excellent as all 34 patients achieved a final cure. Hypokalaemia (47%), shivering (47%), vomiting (35%) and acidity (15%) were most common adverse events. However, we did not observe any serious adverse events. Amphotericin B deoxycholate for relapse visceral leishmaniasis was found to be highly effective and safe. Our study justified to include amphotericin B deoxycholate as a second line drug for visceral leishmaniasis in Bangladesh.

Electronic supplementary material

The online version of this article (10.1186/s13104-018-4036-8) contains supplementary material, which is available to authorized users.

Comprehensive economic evaluation of thermotherapy for the treatment of cutaneous leishmaniasis in Colombia

Background

Cutaneous leishmaniasis causes a high disease burden in Colombia, and available treatments present systemic toxicity, low patient compliance, contraindications, and high costs. The purpose of this study was to estimate the cost-effectiveness of thermotherapy versus Glucantime in patients with cutaneous leishmaniasis in Colombia.

Methods

Cost-effectiveness study from an institutional perspective in 8133 incident cases. Data on therapeutic efficacy and safety were included, calculating standard costs; the outcomes were disability adjusted life years (DALYs) and the number of patients cured. The information sources were the Colombian Public Health Surveillance System, disease burden studies, and one meta-analysis of controlled clinical trials. Incremental cost-effectiveness was determined, and uncertainty was evaluated with tornado diagrams and Monte Carlo simulations.

Results

Thermotherapy would generate costs of US$ 501,621; the handling of adverse effects, US$ 29,224; and therapeutic failures, US$ 300,053. For Glucantime, these costs would be US$ 2,731,276, US$ 58,254, and US$ 406,298, respectively. With thermotherapy, the cost would be US$ 2062 per DALY averted and US$ 69 per patient cured; with Glucantime, the cost would be US$ 4241 per DALY averted and US$ 85 per patient cured. In Monte Carlo simulations, thermotherapy was the dominant strategy for DALYs averted in 67.9% of cases and highly cost-effective for patients cured in 72%.

Conclusion

In Colombia, thermotherapy can be included as a cost-effective strategy for the management of cutaneous leishmaniasis. Its incorporation into clinical practice guidelines could represent savings of approximately US$ 10,488 per DALY averted and costs of US$ 116 per additional patient cured, compared to the use of Glucantime. These findings show the relevance of the incorporation of this treatment in our country and others with similar parasitological, clinical, and epidemiological patterns.

The direct costs of treating human visceral leishmaniasis in Brazil

INTRODUCTION:

The drugs available for visceral leishmaniasis (VL) treatment in Brazil have specific characteristics in terms of operability, effectiveness, toxicity, and cost. The aim of this study was to estimate the direct costs of therapies recommended by the Ministry of Health (MH) for VL treatment in Brazil.

METHODS:

The analytical perspective used was that adopted by the Brazilian Public Health System. Three drugs and four regimens were included: 1) N-methyl glucamine antimoniate intramuscularly at 20mg per kg per day for 30 days; 2) N-methyl glucamine antimoniate intravenously at 20mg per kg per day for 30 days; 3) amphotericin B deoxycholate at 1mg per kg per day for 21 days; and 4) liposomal amphotericin B at 3mg per kg per day for a 7 days treatment.

RESULTS:

The estimated direct costs of treatment for an adult patient using N-methylglucamine antimoniate administered via the intramuscular and intravenous routes were USD 418.52 and USD 669.40, respectively. The estimated cost of treatment with amphotericin B deoxycholate was USD 1,522.70. Finally, the estimated costs of treatment with liposomal amphotericin B were USD 659.79, and USD 11,559.15 using the price adopted by the WHO and the Drug Regulation Board, respectively.

CONCLUSIONS:

This analysis indicates the economic feasibility of replacing N-methyl glucamine antimoniate with liposomal amphotericin B, which allows a shorter treatment period with less toxicity compared with other treatments, provided that the purchase value used by the WHO and transferred to the MH is maintained.

Cost-effectiveness of diagnostic-therapeutic strategies for paediatric visceral leishmaniasis in Morocco

Introduction

Visceral leishmaniasis (VL) is a neglected parasitic disease with a high fatality rate if left untreated. Endemic in Morocco, as well as in other countries in the Mediterranean basin, VL mainly affects children living in rural areas. In Morocco, the direct observation of Leishmania parasites in bone marrow (BM) aspirates is used to diagnose VL and meglumine antimoniate (SB) is the first line of treatment. Less invasive, more efficacious and safer alternatives exist. In this study we estimate the cost-effectiveness of alternative diagnostic-therapeutic algorithms for paediatric VL in Morocco.

Methods

A decision tree was used to estimate the cost-effectiveness of using BM or rapid diagnostic tests (RDTs) as diagnostic tools and/or SB or two liposomal amphotericin B (L-AmB) regimens: 6-day and 2-day courses to treat VL. Incremental cost-effectiveness ratios, expressed as cost per death averted, were estimated by comparing costs and effectiveness of the alternative algorithms. A threshold analysis evaluated at which price L-AmB became cost-effective compared with current practices.

Results

Implementing RDT and/or L-AmB treatments would be cost-effective in Morocco according to the WHO thresholds. Introducing the 6-day course L-AmB, current second-line treatment, would be highly cost-effective if L-AmB price was below US$100/phial. The 2-day L-AmB treatment, current standard treatment of paediatric VL in France, is highly cost-effective, with L-AmB at its market price (US$165/phial).

Conclusions

The results of this study should encourage the implementation of RDT and/or short-course L-AmB treatments for paediatric VL management in Morocco and other North African countries.

Efficacy and safety of amphotericin B deoxycholate versus N-methylglucamine antimoniate in pediatric visceral leishmaniasis: an open-label, randomized, and controlled pilot trial in Brazil

INTRODUCTION

Despite their high toxicity, antimonials and amphotericin B deoxycholate are commonly used for treating visceral leishmaniasis (VL). Few studies showing conflictive data about their efficacy and adverse events in pediatric population are available. This study aimed to evaluate efficacy and safety of amphotericin B deoxycholate vs. that of N-methylglucamine antimoniate in treating pediatric VL in Brazil.

METHODS

This was a randomized, open-label, 2-arm and controlled pilot clinical trial. Treatment naïve children and adolescents with VL without signs of severe illness were treated with N-methylglucamine antimoniate (20mg/kg/day for 20 days) or amphotericin B deoxycholate (1 mg/kg/day for 14 days). All patients were diagnosed with positive direct examination and/or positive PCR for Leishmania spp. performed in bone marrow samples. The primary efficacy end-point was VL cure determined after 180 days of completion of treatment. The analysis was performed using intention-to-treat (ITT) and per protocol (PP) analyses.

RESULTS

In total, 101 volunteers were assessed. Efficacy was similar for both groups. The antimonial (n=51) and amphotericin B groups (n=50) had a cure rate of 94.1% and 100%, and 94% and 97.9% according to ITT and PP analyses, respectively. All patients reported adverse events (AE). Serious AE incidence was similar in both groups. Five individuals were excluded from the study because of severe adverse events.

CONCLUSIONS

N-methylglucamine antimoniate and amphotericin B deoxycholate have similar efficacy and adverse events rate in pediatric patients with VL.

Cost-effectiveness analysis of thermotherapy versus pentavalent antimonials for the treatment of cutaneous leishmaniasis

OBJECTIVE

The treatment of cutaneous leishmaniasis is toxic, has contraindications, and a high cost. The objective of this study was to estimate the cost-effectiveness of thermotherapy versus pentavalent antimonials for the treatment of cutaneous leishmaniasis.

METHODS

Effectiveness was the proportion of healing and safety with the adverse effects; these parameters were estimated from a controlled clinical trial and a meta-analysis. A standard costing was conducted. Average and incremental cost-effectiveness ratios were estimated. The uncertainty regarding effectiveness, safety, and costs was determined through sensitivity analyses.

RESULTS

The total costs were $66,807 with Glucantime and $14,079 with thermotherapy. The therapeutic effectiveness rates were 64.2% for thermotherapy and 85.1% for Glucantime. The average cost-effectiveness ratios ranged between $721 and $1275 for Glucantime and between $187 and $390 for thermotherapy. Based on the meta-analysis, thermotherapy may be a dominant strategy.

CONCLUSION

The excellent cost-effectiveness ratio of thermotherapy shows the relevance of its inclusion in guidelines for the treatment.

How to determine if a model is right for neglected tropical disease decision making

Mathematical and computational modeling can transform decision making for neglected tropical diseases (NTDs) if the right model is used for the right question. Modeling can help better understand and address the complex systems involved in making decisions for NTD prevention and control. However, all models, modelers, and modeling are not the same. Thus, decision makers need to better understand if a particular model actually fits their needs. Here are a series of questions that a decision maker can ask when determining whether a model is right for him or her.

From mouse to man: safety, immunogenicity and efficacy of a candidate leishmaniasis vaccine LEISH-F3+GLA-SE

Key antigens of Leishmania species identified in the context of host responses in Leishmania-exposed individuals from disease-endemic areas were prioritized for the development of a subunit vaccine against visceral leishmaniasis (VL), the most deadly form of leishmaniasis. Two Leishmania proteins-nucleoside hydrolase and a sterol 24-c-methyltransferase, each of which are protective in animal models of VL when properly adjuvanted- were produced as a single recombinant fusion protein NS (LEISH-F3) for ease of antigen production and broad coverage of a heterogeneous major histocompatibility complex population. When formulated with glucopyranosyl lipid A-stable oil-in-water nanoemulsion (GLA-SE), a Toll-like receptor 4 TH1 (T helper 1) promoting nanoemulsion adjuvant, the LEISH-F3 polyprotein induced potent protection against both L. donovani and L. infantum in mice, measured as significant reductions in liver parasite burdens. A robust immune response to each component of the vaccine with polyfunctional CD4 TH1 cell responses characterized by production of antigen-specific interferon-γ, tumor necrosis factor and interleukin-2 (IL-2), and low levels of IL-5 and IL-10 was induced in immunized mice. We also demonstrate that CD4 T cells, but not CD8 T cells, are sufficient for protection against L. donovani infection in immunized mice. Based on the sum of preclinical data, we prepared GMP materials and performed a phase 1 clinical study with LEISH-F3+GLA-SE in healthy, uninfected adults in the United States. The vaccine candidate was shown to be safe and induced a strong antigen-specific immune response, as evidenced by cytokine and immunoglobulin subclass data. These data provide a strong rationale for additional trials in Leishmania-endemic countries in populations vulnerable to VL.

Economic and financial evaluation of neglected tropical diseases

Economic and financing studies are particularly important for decision-making when resources are scarce or considerably limited. This is the case for neglected tropical diseases (NTDs). In fact, the definition of NTDs is an economic one. The shortage of resources for NTD control may be due in large part to the fact that the burden of NTDs and economic value of control measures have not been fully characterized. A number of economic study methodologies are available: cost of illness can quantify the extent, magnitude, and change of a problem; cost of intervention studies can outline the feasibility and guide the design of a policy or intervention; and cost-benefit, cost-effectiveness, and return-on-investment studies can determine the potential value of different interventions and policies. NTDs have unique characteristics that require special consideration in such analyses. Hence, approaches used for other diseases may need modifications to capture the full impact of NTDs. While the existing literature has made important findings, there is a need for substantially more work, as many NTDs and their associated interventions and policies require more evaluation. With increasing work in this area, NTDs may not be as 'neglected' in the future as they are now.

Health economic evaluations of visceral leishmaniasis treatments: a systematic review

Visceral leishmaniasis (VL) is a severe form of the leishmaniasis-disease complex. Its importance to public health relies on its high fatality rate in non-treated cases, the socio-economic impact related to its morbidity, and its endemicity on different continents. The estimated burden of disease of VL varies from 1,969,000 to 2,357,000 Disability Adjusted Life Years (DALYs). VL is classified as a Neglected Tropical Disease (NTD), and is strongly related to poverty and its consequences. Visceral leishmaniasis calls for the development of cost-effective technologies for diagnosis and treatment.

Visceral leishmaniasis (VL), also known as kala azar, is a neglected tropical disease caused by parasitic protozoa of the genus Leishmania. VL is related to poverty and its consequences, which leads to its status of neglected disease. For that reason, cost-effective forms of diagnoses and treatment are very important and still needed. This research aimed at a better understanding of the publications about the technologies currently available, from the standpoint of their economic value. For that purpose, we conducted a systematic review of the literature in order to identify the papers that conducted economic evaluations of technologies used in VL. We initially retrieved 107 articles, which were inspected according to specific guidelines for systematic reviews. After that process, 14 articles matched the inclusion criteria in our review. We classified those studies according to the type of economic evaluation they made, and the methodology used in each one. We found evaluations about a variety of technologies, but the studies were geographically concentrated in Asia, more specifically in India. This concentration is not good because the disease also affects other continents and it is not possible to transfer the economic evaluation from one country or epidemiologic scenario to another.

Neglected tools for neglected diseases: mathematical models in economic evaluations

Despite many current interventions against neglected tropical diseases (NTDs) being highly cost-effective, new strategies are needed to reach the WHO's control and elimination goals. Here we argue for the importance of incorporating economic evaluations of new strategies in decisions regarding resource allocation. Such evaluation should ideally be conducted using dynamic transmission models that capture inherent nonlinearities in transmission and the indirect benefits ('herd effects') of interventions. A systematic review of mathematical models that have been used for economic analysis of interventions against the ten NTDs covered by the London Declaration reveals that only 16 out of 49 studies used dynamic transmission models, highlighting a fundamental--but addressable--gap in the evaluation of interventions against NTDs.

Transmission potential of antimony-resistant leishmania field isolates

We studied the development of antimony-resistant Leishmania infantum in natural vectors Lutzomyia longipalpis and Phlebotomus perniciosus to ascertain the risk of parasite transmission by sand flies. All three resistant strains produced fully mature late-stage infections in sand flies; moreover, the resistant phenotype was maintained after the passage through the vector. These results highlight the risk of circulation of resistant Leishmania strains and question the use of human drugs for treatment of dogs as Leishmania reservoirs.

Drug delivery by tattooing to treat cutaneous leishmaniasis

This study establishes a proof-of-concept that a tattoo device can target intra-dermal drug delivery against cutaneous leishmaniasis (CL). The selected drug is oleylphosphocholine (OlPC) formulated as liposomes, particles known to be prone to macrophage ingestion. We first show that treatment of cultured Leishmania-infected macrophages with OlPC-liposomes results in a direct dose-dependent killing of intracellular parasites. Based on this, in vivo efficacy is demonstrated using a 10 day tattooing-mediated treatment in mice infected with L. major and L. mexicana. In both models this regimen results in rapid clinical recovery with complete regression of skin lesions by Day 28. Parasite counts and histopathology examination confirm high treatment efficacy at the parasitic level. Low amount of drug required for tattooing combined with fast clinical recovery may have a positive impact on CL patient management. This first example of tattoo-mediated drug delivery could open to new therapeutic interventions in the treatment of skin diseases.

Challenges in the therapy of visceral leishmaniasis in Brazil: a public health perspective

Over 3,000 yearly cases of Visceral Leishmaniasis (VL) are reported in Brazil. Brazilian Public Health System provides universal free access to antileishmania therapeutic options: Meglumine Antimoniate, Amphotericin B deoxycholate, and Liposomal Amphotericin B. Even though Amphotericin formulations have been advised for severe disease, this recommendation is mostly based on the opinion of experts and on analogy with studies conducted in other countries. Presently, there are two ongoing multicenter clinical trials comparing the efficacy and safety of the available therapeutic options. Some other issues require further clarification, such as severity markers and the approach to VL/AIDS coinfection. Brazil is facing the challenge of providing access to diagnosis and adequate treatment, in order to avoid VL-related deaths.

Disease control priorities for neglected tropical diseases: lessons from priority ranking based on the quality of evidence, cost effectiveness, severity of disease, catastrophic health expenditures, and loss of productivity

BACKGROUND

In the context of limited health care budgets in countries where Neglected Tropical Diseases (NTDs) are endemic, scaling up disease control interventions entails the setting of priorities. However, solutions based solely on cost-effectiveness analyses may lead to biased and insufficiently justified priorities.

OBJECTIVES

The objectives of this paper are to 1) demonstrate how a range of equity concerns can be used to identify feasible priority setting criteria, 2) show how these criteria can be fed into a multi-criteria decision-making matrix, and 3) discuss the conditions under which this decision-making procedure should be carried out in a real-world decision-making context.

METHODS

This paper draws on elements from theories of decision analysis and ethical theories of fair resource allocation. We explore six typical NTD interventions by employing a modified multi-criteria decision analysis model with predefined criteria, drawn from a priority setting guide under development by the WHO. To identify relevant evidence for the six chosen interventions, we searched the PubMed and Cochrane databases.

DISCUSSION

Our in vitro multi-criteria decision analysis suggested that case management for visceral leishmaniasis should be given a higher priority than mass campaigns to prevent soil-transmitted helminthic infections. This seems to contradict current health care priorities and recommendations in the literature. We also consider procedural conditions that should be met in a contextualised decision-making process and we stress the limitations of this study exercise.

CONCLUSION

By exploring how several criteria relevant to the multi-facetted characteristics of NTDs can be taken into account simultaneously, we are able to suggest how improved priority settings among NTDs can be realised.

Miltefosine: a review of its pharmacology and therapeutic efficacy in the treatment of leishmaniasis

Miltefosine is an alkylphosphocholine drug with demonstrated activity against various parasite species and cancer cells as well as some pathogenic bacteria and fungi. For 10 years it has been licensed in India for the treatment of visceral leishmaniasis (VL), a fatal neglected parasitic disease. It is the first and still the only oral drug that can be used to treat VL and cutaneous leishmaniasis (CL). The standard 28 day miltefosine monotherapy regimen is well tolerated, except for mild gastrointestinal side effects, although its teratogenic potential severely hampers its general use in the clinic and roll-out in national elimination programmes. The pharmacokinetics of miltefosine are mainly characterized by its long residence time in the body, resulting in extensive drug accumulation during treatment and long elimination half-lives. At the moment, different combination therapy strategies encompassing miltefosine are being tested in multiple controlled clinical trials in various geographical areas of endemicity, both in South Asia and East Africa. We here review the most salient pre-clinical and clinical pharmacological aspects of miltefosine, its mechanism of action against Leishmania parasites and other pathogens, and provide a systematic overview of the efficacy and safety data from all clinical trials of miltefosine, either alone or in combination, in the treatment of VL and CL.

Interest in paromomycin for the treatment of visceral leishmaniasis (kala-azar)

Leishmaniasis is an important vector-borne disease, and it is classified as one of the most important tropical fly-borne infections. This disease can cause two types of clinical manifestations: cutaneous forms and visceral forms. Visceral leishmaniasis, which is also called kala-azar, is a very serious infection that can be fatal. The management of visceral leishmaniasis requires informed diagnostic and therapeutic approaches. Continuous research and development regarding the treatment of visceral leishmaniasis had led to many improvements. Paromomycin is a relatively new antibiotic drug that has been used for the treatment of visceral leishmaniasis for several years. This article reviews and discusses the use of paromomycin for visceral leishmaniasis therapy.

The economic value of a visceral leishmaniasis vaccine in Bihar state, India

Visceral leishmaniasis (VL) is responsible for substantial morbidity and mortality and current available treatments have many limitations. The ability of VL infection to generate life-long immunity offers promise for the development of a VL vaccine. A VL vaccine candidate has recently completed phase I clinical trials. We constructed a computer simulation model to determine the potential economic value of a VL vaccine in the endemic region of Bihar state, India. Results found a potential vaccine to be cost-effective (and in many cases economically dominant, i.e., saving costs and providing health benefits) throughout a wide range of vaccination costs and vaccine efficacies, and VL risks. Overall, our study strongly supports the continued development of a VL vaccine.

Lipid nanoparticles containing oryzalin for the treatment of leishmaniasis

Oryzalin is a dinitroaniline drug that has attracted recent interest for the treatment of leishmaniasis. Its use as an antiparasitic therapeutic agent is limited by the low water solubility associated with an in vivo rapid clearance, leading to the administration of larger and possibly toxic doses in in vivo studies, and the use of solvents that may lead to undesirable side effects. In the present work oryzalin-containing lipid nanoparticles were produced by a emulsion-solvent evaporation technique using a composition suitable for parenteral administration, i.e., tripalmitin (solid lipid) and a complex mixture of three emulsifying agents (soya lecithin, Tween® 20 and sodium deoxycholate). Physicochemical characterization included the determination of mean particle size, polydispersity index, zeta potential, encapsulation efficiency and DSC studies. Final formulations revealed values of <140 nm (PI<0.2) and zeta potential of ≈-35 mV, as well as encapsulation efficiency >75%. The effects of various processing parameters, such as lipid and surfactant and composition and concentration, as well as the stability during the harsh procedures of autoclaving (121°C/15 min) and freeze-drying were also evaluated. Formulations revealed to be stable throughout freeze-drying and moist-heath sterilization without significant variations on physicochemical properties and no significant oryzalin losses. The use of a complex surfactant mixture proved crucial for preserving formulation stability. Particularly, lecithin appears as a key component in the stabilization of tripalmitin-based oryzalin-containing lipid nanoparticles. Finally, cell viability studies demonstrated that the incorporation of oryzalin in nanoparticles decreases cytotoxicity, thus suggesting this strategy may improve tolerability and therapeutic index of dinitroanilines.

Study of parasite kinetics with antileishmanial drugs using real-time quantitative PCR in Indian visceral leishmaniasis

OBJECTIVES

This study describes parasite kinetics in the blood of visceral leishmaniasis patients treated with liposomal amphotericin B (L-AmB) or a preformed fat emulsion of amphotericin B (ApL) using real-time quantitative PCR (qPCR).

METHODS

Forty-six patients were treated with a single dose (15 mg/kg of body weight) of either L-AmB (n = 13) or ApL (n = 33). qPCR was used to estimate parasite kinetics by detection of Leishmania donovani DNA using kinetoplast DNA-specific primers in peripheral blood samples using an absolute quantification method.

RESULTS

The mean parasite load decreased from baseline (day 0) values of 894.07 and 980.48 to 71.72 and 211.52 parasite genomes/mL at day 7 in L-AmB and ApL groups, respectively, and at day 30 these further declined to 8.30 and 133.98 parasite genomes/mL, respectively. At day 30 post-treatment evaluation, the decline in parasite load was significantly greater (P = 0.024) with L-AmB compared with ApL. Four of 33 patients in the ApL group failed treatment (1 primary failure and 3 relapses) with the presence of parasites, whereas all patients in the L-AmB group were cured at 6 month follow-up.

CONCLUSIONS

qPCR can be a tool to measure parasite dynamics accurately and provide a marker to measure the efficacy of various drugs. It can be used as a test of cure, allowing us to do away with invasive and risky methods such as splenic or bone marrow aspiration.

Socio-economic aspects of neglected diseases: sleeping sickness and visceral leishmaniasis

Several tropical diseases that are essentially poverty-related have recently gained more attention under the label of 'neglected tropical diseases' or NTD. It is estimated that over 1000 million people currently suffer from one or more NTD. Here, the socio-economic aspects of two NTD - human African trypanosomiasis and human visceral leishmaniasis - are reviewed. Both of these diseases affect the poorest of the poor in endemic countries, cause considerable direct and indirect costs (even though the national control programmes tend to provide free care) and push affected households deeper into poverty.

Modeling transmission dynamics and control of vector-borne neglected tropical diseases

Neglected tropical diseases affect more than one billion people worldwide. The populations most impacted by such diseases are typically the most resource-limited. Mathematical modeling of disease transmission and cost-effectiveness analyses can play a central role in maximizing the utility of limited resources for neglected tropical diseases. We review the contributions that mathematical modeling has made to optimizing intervention strategies of vector-borne neglected diseases. We propose directions forward in the modeling of these diseases, including integrating new knowledge of vector and pathogen ecology, incorporating evolutionary responses to interventions, and expanding the scope of sensitivity analysis in order to achieve robust results.

Cost-effectiveness analysis of combination therapies for visceral leishmaniasis in the Indian subcontinent

Background

Visceral leishmaniasis is a systemic parasitic disease that is fatal unless treated. We assessed the cost and cost-effectiveness of alternative strategies for the treatment of visceral leishmaniasis in the Indian subcontinent. In particular we examined whether combination therapies are a cost-effective alternative compared to monotherapies.

Methods and Findings

We assessed the cost-effectiveness of all possible mono- and combination therapies for the treatment of visceral leishmaniasis in the Indian subcontinent (India, Nepal and Bangladesh) from a societal perspective using a decision analytical model based on a decision tree. Primary data collected in each country was combined with data from the literature and an expert poll (Delphi method). The cost per patient treated and average and incremental cost-effectiveness ratios expressed as cost per death averted were calculated. Extensive sensitivity analysis was done to evaluate the robustness of our estimations and conclusions. With a cost of US$92 per death averted, the combination miltefosine-paromomycin was the most cost-effective treatment strategy. The next best alternative was a combination of liposomal amphotericin B with paromomycin with an incremental cost-effectiveness of $652 per death averted. All other strategies were dominated with the exception of a single dose of 10mg per kg of liposomal amphotericin B. While strategies based on liposomal amphotericin B (AmBisome) were found to be the most effective, its current drug cost of US$20 per vial resulted in a higher average cost-effectiveness. Sensitivity analysis showed the conclusion to be robust to variations in the input parameters over their plausible range.

Conclusions

Combination treatments are a cost-effective alternative to current monotherapy for VL. Given their expected impact on the emergence of drug resistance, a switch to combination therapy should be considered once final results from clinical trials are available.

Visceral leishmaniasis (VL) is a serious health problem in the Indian subcontinent affecting the rural poor. It has a significant economic impact on concerned households. The development of drug resistance is a major problem and threatens control efforts under the VL elimination initiative. With an unprecedented choice of antileishmanial drugs (but no newer compound in clinical development), policies that protect these drugs against the emergence of resistance are required. A possible strategy that has been successfully used for malaria and tuberculosis is the use of combination therapies. This study is the first comprehensive assessment of the cost-effectiveness of all possible mono- and combination therapies for the treatment of visceral leishmaniasis in the Indian subcontinent. The analysis was done from the societal perspective, including both health provider and household costs. The present work shows that combination treatments are a cost-effective alternative to current monotherapy for VL. Given their expected impact on emergence of drug resistance, the use of combination therapy should be considered in the context of the VL elimination programme in the Indian subcontinent.

A probabilistic risk assessment for deployed military personnel after the implementation of the "Leishmaniasis Control Program" at Tallil Air Base, Iraq

Leishmaniasis has been of concern to the U.S. military and has re-emerged in importance because of recent deployments to the Middle East. We conducted a retrospective probabilistic risk assessment for military personnel potentially exposed to insecticides during the "Leishmaniasis Control Plan" (LCP) undertaken in 2003 at Tallil Air Base, Iraq. We estimated acute and subchronic risks from resmethrin, malathion, piperonyl butoxide (PBO), and pyrethrins applied using a truck-mounted ultra-low-volume (ULV) sprayer and lambda-cyhalothrin, cyfluthrin, bifenthrin, chlorpyrifos, and cypermethrin used for residual sprays. We used the risk quotient (RQ) method for our risk assessment (estimated environmental exposure/toxic endpoint) and set the RQ level of concern (LOC) at 1.0. Acute RQs for truck-mounted ULV and residual sprays ranged from 0.00007 to 33.3 at the 95th percentile. Acute exposure to lambda-cyhalothrin, bifenthrin, and chlorpyrifos exceeded the RQ LOC. Subchronic RQs for truck-mounted ULV and residual sprays ranged from 0.00008 to 32.8 at the 95th percentile. Subchronic exposures to lambda-cyhalothrin and chlorpyrifos exceeded the LOC. However, estimated exposures to lambda-cyhalothrin, bifenthrin, and chlorpyrifos did not exceed their respective no observed adverse effect levels.

Postgenomic research on leishmaniasis: a critical self-appraisal

Scientific conferences, a major feature of academic life, rarely provide the opportunity for self-appraisal of a research field. During a 2007 meeting on leishmaniasis research in the postgenomic era, approximately 60 researchers participated in group discussions that aimed to provide a critical self-appraisal of the state of the field and to highlight major roadblocks that are likely to prevent the translation of new research into tools for leishmaniasis control. These discussions demonstrated a surprising concordance of views and highlighted several crucial areas for future development.

Antileishmanial and antitrypanosomal activity of bufadienolides isolated from the toad Rhinella jimi parotoid macrogland secretion

Amphibian skin secretions are considered a rich source of biologically active compounds and are known to be rich in peptides, bufadienolides and alkaloids. Bufadienolides are cardioactive steroids from animals and plants that have also been reported to possess antimicrobial activities. Leishmaniasis and American Trypanosomiasis are parasitic diseases found in tropical and subtropical regions. The efforts toward the discovery of new treatments for these diseases have been largely neglected, despite the fact that the only available treatments are highly toxic drugs. In this work, we have isolated, through bioguided assays, the major antileishmanial compounds of the toad Rhinella jimi parotoid macrogland secretion. Mass spectrometry and (1)H and (13)C NMR spectroscopic analyses were able to demonstrate that the active molecules are telocinobufagin and hellebrigenin. Both steroids demonstrated activity against Leishmania (L.) chagasi promastigotes, but only hellebrigenin was active against Trypanosoma cruzi trypomastigotes. These steroids were active against the intracellular amastigotes of Leishmania, with no activation of nitric oxide production by macrophages. Neither cytotoxicity against mouse macrophages nor hemolytic activities were observed. The ultrastructural studies with promastigotes revealed the induction of mitochondrial damage and plasma membrane disturbances by telocinobufagin, resulting in cellular death. This novel biological effect of R. jimi steroids could be used as a template for the design of new therapeutics against Leishmaniasis and American Trypanosomiasis.

Comparison of miltefosine and meglumine antimoniate for the treatment of zoonotic cutaneous leishmaniasis (ZCL) by a randomized clinical trial in Iran

This study was a randomized, open label comparison that was designed to determine efficacy and safety of miltefosine as the first oral drug for the treatment of zoonotic cutaneous leishmaniasis caused by Leishmania major in comparison with meglumine antimoniate. Complete clinical response was defined as 100% re-epithelialization of the lesion. Definitions of lesion cure and failure were based on both clinical and parasitological criteria two weeks after the end of treatment and clinical recovery three months after this period. Of 32 patients enrolled for miltefosine treatment 28 patients completed treatment, of which 26 were cured at three months, corresponding to a cure rate of 92.9% on a per protocol analysis, and 81.3% according to intention to treat analysis. There was one failure (3.1%), one relapse (3.1%) and four dropouts due to lack of tolerability (12.5%) during the first week of treatment. Of 31 patients who received intramuscular meglumine antimoniate (20mgSb(5)/kg body weight daily for 14 days) 25 were cured (83.3% on a per protocol basis, 80.6% on intention to treat basis), five failed (16.1%) and one was lost (3.2%) at 3-month follow-up. At 6-month follow-up after the end of treatment, no relapse was observed. Both regimens were tolerated but averages of nausea (32.2%) and vomiting (21.5%) were observed in patients during two weeks after initiation of miltefosine treatment. Other gastrointestinal, musculoskeletal, and total adverse events were not statistically different in the two groups during one to four weeks after therapy initiation. No relevant changes were observed in levels of liver enzymes, creatinine and hematological tests before and after end of treatment in both groups. In conclusion, miltefosine is apparently at least as good as meglumine antimoniate for the treatment of cutaneous leishmaniasis caused by L. major in Iran, based on parasitological as well as clinical criteria two weeks, three months, and six months after end of treatment.