Do the diminishing efficacy and increasing toxicity of sodium stibogluconate in the treatment of visceral leishmaniasis in Bihar, India, justify its continued use as a first-line drug? An observational study of 80 cases

Treatment options for leishmaniasis

Leishmaniasis is broadly classified into three types: cutaneous, mucocutaneous and visceral. The visceral form is most dangerous and can result in death. Although leishmaniasis is an ancient disease, its treatment is still challenging. Several drugs, differing in their cost, toxicity, treatment duration and emergence of drug resistance, are used for different types of leishmaniasis. To overcome these limitations, the search for newer drugs and other treatments continues. In this article, we discuss conventional drugs, other treatments, including newer options such as immunotherapy and immunochemotherapy, and future prospects for leishmaniasis treatment.

Efficacy and Safety of Paromomycin for Visceral Leishmaniasis: A Systematic Review

Visceral leishmaniasis, also known as kala-azar is one of the most commonly neglected tropical diseases affecting a large number of rural and resource-limited people in South Asia, Africa, and South America. Paromomycin, an aminoglycoside drug, is frequently used for the treatment of visceral leishmaniasis. Despite limited therapies for visceral leishmaniasis and emerging drug resistance, a proper review on the action of paromomycin for kala-azar is lacking. This systematic review aims to look for the efficacy and safety aspects of paromomycin for the treatment of visceral leishmaniasis.

Exploiting knowledge on pharmacodynamics-pharmacokinetics for accelerated anti-leishmanial drug discovery/development

Introduction: Being on the top list of neglected tropical diseases, leishmaniasis has been marked for elimination by 2020. In the light of small armamentarium of drugs and their associated drawbacks, the understanding of pharmacodynamics and/or pharmacokinetics becomes a priority to achieve and sustain disease elimination. Areas covered: The authors have looked into pharmacological aspects of existing and emerging drugs for treatment of leishmaniasis. An in-depth understanding of pharmacodynamics and pharmacokinetics (PKPD) provides a rationale for drug designing and optimizing the treatment strategies. It forms a key to prevent drug resistance and avoid drug-associated adverse effects. The authors have compiled the researches on the PKPD of different anti-leishmanial formulations that have the potential for improved and/or effective disease intervention. Expert opinion: Understanding the pharmacological aspects of drugs forms the basis for the clinical application of novel drugs. Tailoring drug dosage and individualized treatment can avoid the adverse events and bridge gap between the in vitro models and their clinical application. An integrated approach, with pragmatic use of technological advances can improve phenotypic screening and physiochemical properties of novel drugs. Concomitantly, this can serve to improve clinical efficacies, reduce the incidence of relapse and accelerate the drug discovery/development process for leishmaniasis elimination.

Emerging therapeutic targets for treatment of leishmaniasis

INTRODUCTION

Parasitic diseases that pose a threat to human life include leishmaniasis - caused by protozoan parasite Leishmania species. Existing drugs have limitations due to deleterious side effects like teratogenicity, high cost and drug resistance. This calls for the need to have an insight into therapeutic aspects of disease. Areas covered: We have identified different drug targets via. molecular, imuunological, metabolic as well as by system biology approaches. We bring these promising drug targets into light so that they can be explored to their maximum. In an effort to bridge the gaps between existing knowledge and prospects of drug discovery, we have compiled interesting studies on drug targets, thereby paving the way for establishment of better therapeutic aspects. Expert opinion: Advancements in technology shed light on many unexplored pathways. Further probing of well established pathways led to the discovery of new drug targets. This review is a comprehensive report on current and emerging drug targets, with emphasis on several metabolic targets, organellar biochemistry, salvage pathways, epigenetics, kinome and more. Identification of new targets can contribute significantly towards strengthening the pipeline for disease elimination.

Treatment Outcome of the Drug-resistant Zoonotic Cutaneous Leishmaniasis by Glucantime

BACKGROUND

Resistance of Leishmania species to antimonial drugs has increased. Hence, in the present study Leishmania major isolates were collected from patients with resistance phenotype and the presence/absence of resistance to Glucantime was investigated.

MATERIALS AND METHODS

Samples were taken from 10 cutaneous leishmaniasis (CL) patients who had not responded to chemotherapy with Glucantime. Nested polymerase chain reaction (PCR) was performed to identify the isolated species. Stationary phase promastigotes were added to the grown, adhesive J774 macrophages. Values obtained from standard strain were compared with the test cultures after exposure to the medicine. In vivo, the effects of Glucantime were assessed by comparing the sizes and the parasite burden of the lesions on mouse model.

RESULTS

The results of amplified band on agarose gel demonstrated all samples were L. major. After exposure to medicine, a reduction of intracellular amastigotes to half was detected. In vivo, the parasite was eliminated in 90% of mice with lesions caused by both isolates of patients and standard L. major, and their lesions became smaller significantly.

CONCLUSION

Pentavalent antimonial (SbV) salts are the main component of chemotherapy against leishmaniasis. However, the medicine has been found ineffective. In the present study, isolates from patients with no response to treatment had no significant difference from the standard L. major strain (as the sensitive strain). Therefore, in patients with resistance phenotype to Glucantime, the parasites did not actually have intrinsic resistance, i.e., environmental and host factors prevented the successful treatment of the disease.

Laboratory confirmed miltefosine resistant cases of visceral leishmaniasis from India

BACKGROUND

Miltefosine unresponsive and relapse cases of visceral leishmaniasis (VL) are increasingly being reported. However, there has been no laboratory confirmed reports of miltefosine resistance in VL. Here, we report two laboratory confirmed cases of VL from India.

METHODS

Two patients with VL were referred to us with suspected VL. The first patient was a native of the VL endemic state of Bihar, but residing in Delhi, a VL non-endemic area. He was treated with broad-spectrum antibiotics and antipyretics but was unresponsive to treatment. The second patient was from Jharkhand state in eastern India (adjoining Bihar), another endemic state for VL. He was refractory to anti-leishmanial treatment, which included administration of miltefosine. Following investigation, both patients were serologically positive for VL, and blood buffy coat from both patients grew Leishmania donovani. The isolates derived from both cases were characterized for their drug susceptibility, genetically characterised, and SNPs typed for LdMT and LdROS gene expression. Both patients were successfully treated with amphotericin B.

RESULTS

The in vitro drug susceptibility assays carried out on both isolates showed good IC₅₀ values to amphotericin B (0.1 ± 0.0004 μg/ml and 0.07 ± 0.0019 μg/ml). One isolate was refractory to Sb^III with an IC₅₀ of > 200 μM while the second isolate was sensitive to Sb^III with an IC₅₀ of 36.70 ± 3.2 μM. However, in both the isolates, IC₅₀ against miltefosine was more than 10-fold higher (> 100 μM) than the standard strain DD8 (6.8 ± 0.1181 μM). Furthermore, genetic analyses demonstrated single nucleotide polymorphisms (SNPs) (₃₅₄Tyr↔Phe and ₁₀₇₈Phe↔Tyr) in the LdMT gene of the parasites.

CONCLUSIONS

Here, we document two laboratory confirmed cases of miltefosine resistant VL from India. Our finding highlights the urgent need to establish control measures to prevent the spread of these strains. We also propose that LdMT gene mutation analysis could be used as a molecular marker of miltefosine resistance in L. donovani.

Contribution of environmental toxins in the pathogenesis of idiopathic cardiomyopathies

OPINION STATEMENT

The pathogenesis of idiopathic cardiomyopathies is likely highly complex and remains elusive. Environmental toxins have been hypothesized to possibly cause a subset of cardiomyopathies. Epidemiological, preclinical, and small clinical studies have investigated the role of numerous elements and compounds in the pathogenesis of these myocardial disorders. In this review, we present the evidence implicating elements and environmental compounds in myocardial toxicity, including antimony, cobalt, mercury, aluminum, copper, and acrolein. We discuss their sources, toxic effects, and epidemiology, as well as identify groups at risk for toxic exposure. Through our discussion, we highlight areas where further investigation into the clinical effects of these possible toxins is warranted.

Challenges for management of post kala-azar dermal leishmaniasis and future directions

Post kala-azar dermal leishmaniasis (PKDL) is a skin complication resulting from infection with Leishmania donovani (LD) parasite. It mostly affects individuals who have previously suffered from visceral leishmaniasis (VL) caused by LD. In some cases, PKDL develops among people infected with LD, but do not show any symptoms of VL. Clinical presentation includes hypopigmented macules/papules/nodules or polymorphic lesions (combination of two or more lesions). Except for skin lesions, PKDL patients are generally healthy and usually do not seek medical care. These patients play an important role in interepidemic transmission of the infection and subsequent VL outbreak. Therefore, proper diagnosis and treatment of PKDL patients is important for the control of VL in endemic countries, especially in the Indian subcontinent where VL is anthroponotic. Here, we report the challenges in the estimation of PKDL burden, its diagnosis, and treatment, and suggest possible solutions based on recent literature, reports, published manuals, and web-based information.

Species-directed therapy for leishmaniasis in returning travellers: a comprehensive guide

Background

Leishmaniasis is increasingly reported among travellers. Leishmania species vary in sensitivity to available therapies. Fast and reliable molecular techniques have made species-directed treatment feasible. Many treatment trials have been designed poorly, thus developing evidence-based guidelines for species-directed treatment is difficult. Published guidelines on leishmaniasis in travellers do not aim to be comprehensive or do not quantify overall treatment success for available therapies. We aimed at providing comprehensive species-directed treatment guidelines.

Methodology/Principal Findings

English literature was searched using PubMed. Trials and observational studies were included if all cases were parasitologically confirmed, the Leishmania species was known, clear clinical end-points and time points for evaluation of treatment success were defined, duration of follow-up was adequate and loss to follow-up was acceptable. The proportion of successful treatment responses was pooled using mixed effects methods to estimate the efficacy of specific therapies. Final ranking of treatment options was done by an expert panel based on pooled efficacy estimates and practical considerations. 168 studies were included, with 287 treatment arms. Based on Leishmania species, symptoms and geography, 25 clinical categories were defined and therapy options ranked. In 12/25 categories, proposed treatment agreed with highest efficacy data from literature. For 5/25 categories no literature was found, and in 8/25 categories treatment advise differed from literature evidence. For uncomplicated cutaneous leishmaniasis, combination of intralesional antimony with cryotherapy is advised, except for L. guyanensis and L. braziliensis infections, for which systemic treatment is preferred. Treatment of complicated (muco)cutaneous leishmaniasis differs per species. For visceral leishmaniasis, liposomal amphotericin B is treatment of choice.

Conclusions/Significance

Our study highlights current knowledge about species-directed therapy of leishmaniasis in returning travellers and also demonstrates lack of evidence for treatment of several clinical categories. New data can easily be incorporated in the presented overview. Updates will be of use for clinical decision making and for defining further research.

Human leishmaniasis is caused by unicellular parasites that are injected into the skin by sand-flies, small, flying insects. Many different Leishmania species cause various manifestations of disease, both of the skin and internal organs. Leishmaniasis is a curable disease but clear guidelines on the best available treatment are lacking. Leishmania species differ in sensitivity to available drugs. Until recently, identification of the infecting Leishmania parasite was laborious, thus therapy could not precisely be targeted to the infecting species, in contrast to many other infectious diseases. Nowadays, Leishmania parasites can be identified relatively easily with new DNA techniques. We studied efficacy of therapies for diseases due to different Leishmania species, limited to the English literature. Efficacy was summarized and presented in an easy to read format. Because of difficulties with identification of parasite species in earlier studies, quality of evidence was often limited. Our findings are a major help for clinicians to easily find optimal treatment for specific patients. Moreover, our results demonstrate where additional research is needed to further improve treatment of leishmaniasis.

Tinospora cordifolia as a protective and immunomodulatory agent in combination with cisplatin against murine visceral leishmaniasis

Effect of pure herb, Tinospora cordifolia was studied for its hepatoprotective, nephroprotective and immunomodulatory activity against high dose cisplatin treatment in Leishmania donovani infected BALB/c mice. Administration of cisplatin (5mg/kg b.wt. daily for 5 days, i.p.) reduced the parasite load in L. donovani infected BALB/c mice but produced damage in liver and kidney as manifested biochemically by an increase in serum glutamate oxaloacetate transaminase (SGOT), serum glutamate pyruvate transaminase (SGPT), serum urea, serum creatinine and various electrolytes etc. These biochemical analyses were further supported by cisplatin induced morphological changes in kidney, liver and spleen. To combat this pure herb, T. cordifolia (100mg/kg b.wt. for 15 days daily) was used in combination with cisplatin in L. donovani infected BALB/c mice and it was found that all the aforementioned changes were effectively attenuated by T. cordifolia when administered in combination with cisplatin. Moreover, flow cytometric analysis of lymphocyte surface markers of T cells (CD3+, CD4+ and CD8+), NK1.1 and B cells (CD19) indicated prominent enhancement in proliferation and differentiation of lymphocytes. T. cordifolia in combination with cisplatin selectively induced Th1 type of immune response as depicted by enhanced levels of IFN-γ and IL-2 whereas Th2 specific cytokines IL-4 and IL-10 observed a moderate decline. Confirmation of Th1 polarization was further obtained from augmented levels of IgG2a over IgG1 and heightened DTH (delayed type hypersensitivity) response. Thus, our results suggest that treatment by T. cordifolia may be a critical remedy for the amelioration of adverse effects of cisplatin. Thus, this might serve as a novel combination against visceral leishmaniasis in future.

A comparative evaluation of amphotericin B and sodium antimony gluconate, as first-line drugs in the treatment of Indian visceral leishmaniasis

In a study to evaluate the relative efficacies of sodium antimony gluconate (SAG) and amphotericin B (AMB), each drug was used to treat 60 Indian cases of visceral leishmaniasis (VL). At the time of treatment, each case had recently been parasitologically confirmed. The patients received either 20 mg SAG/kg daily, by intramuscular injection, for 4 weeks, or 1 mg AMB/kg daily, infused slowly over 2 h, with no incremental dosage, for 20 days. The response of the patients was followed clinically and by the microscopical examination of bone-marrow aspirates (BMA). The infected macrophages in subsamples of the BMA collected pre-treatment were cultured so that the drug sensitivities of the parasites, to 20 microg SAG or 1 microg AMB/ml medium, could be determined in vitro. Other subsamples of the BMA were used to set up promastigote cultures that were then used to infect BALB/c mice. The responses of the mice to 5 days of treatment with SAG or AMB (at the same daily dosages as used in the clinical trials) were subsequently explored. SAG only cured 46.6% of the patients given the drug, only cleared amastigotes from 38.3% of the macrophage cultures, and only cured 53.3% of the infected mice. The corresponding values for AMB - 100%, 100% and 100% - were markedly higher (P <0.001 for each comparison). Although nine patients had to be withdrawn from the SAG group (all because of cardiac toxicity), all of the patients given AMB completed their treatment without any serious adverse effects (P <0.01). Two of the patients withdrawn from the SAG arm died shortly after their withdrawal; earlier withdrawal may have saved them. At least in the setting of the present study, AMB appears far superior to SAG as a first-line drug against VL and should replace it.

Treatment of visceral leishmaniasis

The available treatment options for visceral leishmaniasis (VL) have problems relating to efficacy, adverse effects and cost, making treatment a complex issue. We review the evidence relating to the different methods of treatment in relation to - efficacy and toxicity of the drugs in different areas of the world; ability to monitor side effects, length of treatment; ability of patients to pay for and stay safe during treatment, ability of the healthcare services to give intramuscular, intravenous or oral therapy; the sex and child-bearing potential of the patient and the immune status of the patient. The high mortality of untreated/ poorly treated VL infection makes the decisions paramount, but a unified and coordinated response by each area is likely to be more effective and informative to future policies than an ad hoc response. For patients in resource-rich countries, liposomal amphotericin B appears to be the optimal treatment. In South Asia, miltefosine is being used; the combination of single dose liposomal amphotericin B and short course miltefosine looks encouraging but has the problem of potential reproductive toxicities in females. In Africa, the evidence to switch from SSG is not yet compelling. The need to monitor and plan for evolving drug failure, secondary to leishmania parasite resistance, is paramount. With a few drugs the options may be limited; however, we await key ongoing trials in both Africa and India to explore the effects of combination treatment. If safe and reliable combinations are revealed by the ongoing studies, it is far from clear as to whether this will avoid leishmania parasite resistance. The development of new drugs to add to the armamentarium is paramount. Lessons can be learnt from the management of diseases such as tuberculosis and malaria in terms of planning the switch to combination treatment. As important as establishing the best choice for specific antileishmanial agent is ensuring treatment centers, which can best manage the problems encountered during treatment, specifically malnutrition, bleeding, intercurrent infections, drug side effects and detecting and treating underlying immunosuppression.

Leishmanicidal activity of the Agaricus blazei Murill in different Leishmania species

Leishmaniasis is a major public health problem, and the alarming spread of parasite resistance underlines the importance of discovering new therapeutic products. The present study aims to investigate the in vitro leishmanicidal activity of an Agaricus blazei Murill mushroom extract as compared to different Leishmania species and stages. The water extract proved to be effective against promastigote and amastigote-like stages of Leishmania amazonensis, L. chagasi, and L. major, with IC(50) (50% inhibitory concentration) values of 67.5, 65.8, and 56.8 μg/mL for promastigotes, and 115.4, 112.3, and 108.4 μg/mL for amastigotes-like respectively. The infectivity of the three Leishmania species before and after treatment with the water extract was analyzed, and it could be observed that 82%, 57%, and 73% of the macrophages were infected with L. amazonensis, L. major, and L. chagasi, respectively. However, when parasites were pre-incubated with the water extract, and later used to infect macrophages, they were able to infect only 12.7%, 24.5%, and 19.7% of the phagocytic cells for L. amazonensis, L. chagasi, and L. major, respectively. In other experiments, macrophages were infected with L. amazonensis, L. chagasi, or L. major, and later treated with the aforementioned extract, presented reductions of 84.4%, 79.6%, and 85.3% in the parasite burden after treatment. A confocal microscopy revealed the loss of the viability of the parasites within the infected macrophages after treatment with the water extract. The applied extract presented a low cytotoxicity in murine macrophages and a null hemolytic activity in type O(+) human red blood cells. No nitric oxide (NO) production, nor inducible nitric oxide syntase expression, could be observed in macrophages after stimulation with the water extract, suggesting that biological activity may be due to direct mechanisms other than macrophage activation by means of NO production. In conclusion, the results demonstrate that the A. blazei Murill water extract can potentially be used as a therapeutic alternative on its own, or in association with other drugs, to treat Visceral and Cutaneous Leishmaniasis.

Use of antimony in the treatment of leishmaniasis: current status and future directions

In the recent past the standard treatment of kala-azar involved the use of pentavalent antimonials Sb(V). Because of progressive rise in treatment failure to Sb(V) was limited its use in the treatment program in the Indian subcontinent. Until now the mechanism of action of Sb(V) is not very clear. Recent studies indicated that both parasite and hosts contribute to the antimony efflux mechanism. Interestingly, antimonials show strong immunostimulatory abilities as evident from the upregulation of transplantation antigens and enhanced T cell stimulating ability of normal antigen presenting cells when treated with Sb(V) in vitro. Recently, it has been shown that some of the peroxovanadium compounds have Sb(V)-resistance modifying ability in experimental infection with Sb(V) resistant Leishmania donovani isolates in murine model. Thus, vanadium compounds may be used in combination with Sb(V) in the treatment of Sb(V) resistance cases of kala-azar.

Paromomycin for the treatment of visceral leishmaniasis in Sudan: a randomized, open-label, dose-finding study

Background

A recent study has shown that treatment of visceral leishmaniasis (VL) with the standard dose of 15 mg/kg/day of paromomycin sulphate (PM) for 21 days was not efficacious in patients in Sudan. We therefore decided to test the efficacy of paramomycin for a longer treatment duration (15 mg/kg/day for 28 days) and at the higher dose of 20 mg/kg/day for 21 days.

Methods

This randomized, open-label, dose-finding, phase II study assessed the two above high-dose PM treatment regimens. Patients with clinical features and positive bone-marrow aspirates for VL were enrolled. All patients received their assigned courses of PM intramuscularly and adverse events were monitored. Parasite clearance in bone-marrow aspirates was tested by microscopy at end of treatment (EOT, primary efficacy endpoint), 3 months (in patients who were not clinically well) and 6 months after EOT (secondary efficacy endpoint). Pharmacokinetic data were obtained from a subset of patients weighing over 30 kg.

Findings

42 patients (21 per group) aged between 4 and 60 years were enrolled. At EOT, 85% of patients (95% confidence interval [CI]: 63.7% to 97.0%) in the 20 mg/kg/day group and 90% of patients (95% CI: 69.6% to 98.8%) in the 15 mg/kg/day group had parasite clearance. Six months after treatment, efficacy was 80.0% (95% CI: 56.3% to 94.3%) and 81.0% (95% CI: 58.1% to 94.6%) in the 20 mg/kg/day and 15 mg/kg/day groups, respectively. There were no serious adverse events. Pharmacokinetic profiles suggested a difference between the two doses, although numbers of patients recruited were too few to make it significant (n = 3 and n = 6 in the 20 mg/kg/day and 15 mg/kg/day groups, respectively).

Conclusion

Data suggest that both high dose regimens were more efficacious than the standard 15 mg/kg/day PM for 21 days and could be further evaluated in phase III studies in East Africa.

Trial Registration

ClinicalTrials.gov NCT00255567

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.

Geographical variation in the response of visceral leishmaniasis to paromomycin in East Africa: a multicentre, open-label, randomized trial

Background

Visceral leishmaniasis (VL) is a major health problem in developing countries. The untreated disease is fatal, available treatment is expensive and often toxic, and drug resistance is increasing. Improved treatment options are needed. Paromomycin was shown to be an efficacious first-line treatment with low toxicity in India.

Methods

This was a 3-arm multicentre, open-label, randomized, controlled clinical trial to compare three treatment regimens for VL in East Africa: paromomycin sulphate (PM) at 15 mg/kg/day for 21 days versus sodium stibogluconate (SSG) at 20 mg/kg/day for 30 days; and the combination of both dose regimens for 17 days. The primary efficacy endpoint was cure based on parasite-free tissue aspirates taken 6 months after treatment.

Findings

Overall, 135 patients per arm were enrolled at five centres in Sudan (2 sites), Kenya (1) and Ethiopia (2), when the PM arm had to be discontinued due to poor efficacy. The trial has continued with the higher dose of PM as well as the combination of PM and SSG arms. These results will be reported later. Baseline patient characteristics were similar among treatment arms. The overall cure with PM was significantly inferior to that with SSG (63.8% versus 92.2%; difference 28.5%, 95%CI 18.8% to 38.8%, p<0.001). The efficacy of PM varied among centres and was significantly lower in Sudan (14.3% and 46.7%) than in Kenya (80.0%) and Ethiopia (75.0% and 96.6%). No major safety issues with PM were identified.

Conclusion

The efficacy of PM at 15 mg/kg/day for 21 days was inadequate, particularly in Sudan. The efficacy of higher doses and the combination treatment warrant further studies.

Visceral leishmaniasis (VL) is a fatal parasitic disease with 500,000 new cases each year according to WHO estimates. New and better treatment options are urgently needed in disease endemic areas due to the long courses, toxicity and development of resistance to current treatments. Recently, the antibiotic paromomycin was tested and registered in India to treat this disease. The current study describes a clinical trial to test the effectiveness of injectable paromomycin, either alone or in combination with the standard drug sodium stibogluconate in three East African countries—Sudan, Kenya and Ethiopia. The study showed that at the same paromomycin dose that was successfully used and registered in India, a far poorer outcome was obtained, particularly in Sudan, suggesting that there are either differences in the patients ability to respond to the drug or in the susceptibility of parasites in East Africa compared with those in India. However, no major safety concerns were noted with the treatment. Further research was initiated to see if a higher dose of paromomycin would perform better, especially in Sudan. The results of this and the performance of the combination arm will be reported later. Our study highlights the importance of considering geographical differences to treatment responses.

Effectiveness and safety of liposomal amphotericin B for visceral leishmaniasis under routine program conditions in Bihar, India

We evaluated, through the prospective monitoring of 251 patients at Sadar Hospital in Bihar, India, the effectiveness and safety of 20 mg/kg body weight of liposomal amphotericin B for the treatment of visceral leishmaniasis. The treatment success rates for the intention-to-treat, per protocol, and intention-to-treat worse-case scenario analyses were 98.8%, 99.6%, and 81.3%, respectively. Nearly one-half of patients experienced mild adverse events, but only 1% developed serious but non-life-threatening lips swelling. The lost to follow-up rate was 17.5%. Our findings indicate that the 20 mg/kg body weight treatment dosage is effective and safe under routine program conditions. Given that the exorbitant cost of liposomal amphotericin B is a barrier to its widespread use, we recommend further study to monitor and evaluate a lowered dosage and a shorter treatment course.

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.

Recent strategies for the chemotherapy of visceral leishmaniasis

Visceral leishmaniasis is a widespread and deadly disease. First-line drugs are antimonials, but amphotericin B and its lipid formulations B is used for treating visceral leishmaniasis that is unresponsive to antimony. New therapeutic approaches are being actively developed, including the following: use of drug carriers targeted specifically to the parasite location, thus reduce adverse effects of drug; use of immunomodulating drugs; evaluation of natural products; pharmacokinetic studies; and drug combinations. Recent clinical trials with paromomycin and miltefosine were successful and these drugs appear to be promising for the future therapy of visceral leishmaniasis. Furthermore, identification and therapeutic evaluation of specific targets in the Leishmania organism could lead to new compounds, such as antileishmanial drugs and reversal agents of drug resistance.

Injectable paromomycin for Visceral leishmaniasis in India

BACKGROUND

Visceral leishmaniasis (kala-azar) affects large, rural, resource-poor populations in South Asia, Africa, and Brazil. Safe, effective, and affordable new therapies are needed. We conducted a randomized, controlled, phase 3 open-label study comparing paromomycin, an aminoglycoside, with amphotericin B, the present standard of care in Bihar, India.

METHODS

In four treatment centers for visceral leishmaniasis, 667 patients between 5 and 55 years of age who were negative for the human immunodeficiency virus and had parasitologically confirmed visceral leishmaniasis were randomly assigned in a 3:1 ratio to receive paromomycin (502 patients) at a dose of 11 mg per kilogram of body weight intramuscularly daily for 21 days or amphotericin B (165 patients) at a dose of 1 mg per kilogram intravenously every other day for 30 days. Final cure was assessed 6 months after the end of treatment; safety assessments included daily clinical evaluations and weekly laboratory and audiometric evaluations. Noninferiority testing was used to compare 6-month cure rates, with a chosen margin of noninferiority of 10 percentage points.

RESULTS

Paromomycin was shown to be noninferior to amphotericin B (final cure rate, 94.6% vs. 98.8%; difference, 4.2 percentage points; upper bound of the 97.5% confidence interval, 6.9; P<0.001). Mortality rates in the two groups were less than 1%. Adverse events, which were more common among patients receiving paromomycin than among those receiving amphotericin B (6% vs. 2%, P=0.02), included transient elevation of aspartate aminotransferase levels (>3 times the upper limit of the normal range); transient reversible ototoxicity (2% vs. 0, P=0.20); and injection-site pain (55% vs. 0, P<0.001); and in patients receiving amphotericin B, as compared with those receiving paromomycin, nephrotoxicity (4% vs. 0, P<0.001), fevers (57% vs. 3%), rigors (24% vs. 0, P<0.001), and vomiting (10% vs. <1%, P<0.001).

CONCLUSIONS

Paromomycin was shown to be noninferior to amphotericin B for the treatment of visceral leishmaniasis in India. (ClinicalTrials.gov number, NCT00216346.)

Echocardiographic evaluation of cardiac status in Indian visceral leishmaniasis patients

Visceral leishmaniasis (VL) is endemic in many countries worldwide, including India. Globally, sodium stibogluconate (Sb) remains the cornerstone of therapy, except in some parts of India owing to increasing drug resistance. Although electrocardiographic changes associated with Sb therapy have been described, global cardiac function using tools such as colour Doppler echocardiography is less well studied. We evaluated the cardiac function of 14 newly diagnosed VL patients using two-dimensional M-mode and Doppler echocardiography. The evaluations were performed before, during and at the end of Sb therapy. Left ventricular function and dimensions remained within normal limits in all patients. Pericardial effusion was noted in four patients with heavy parasitaemia. Effusions were small, haemodynamically insignificant and resolved spontaneously. We conclude that pericardial effusion may occur in VL patients with heavy parasitaemia.

Chemotherapy in the treatment and control of leishmaniasis

Drugs remain the most important tool for the treatment and control of both visceral and cutaneous leishmaniasis. Although there have been several advances in the past decade, with the introduction of new therapies by liposomal amphotericin, oral miltefosine and paromomycin (PM), these are not ideal drugs, and improved shorter duration, less toxic and cheaper therapies are required. Treatments for complex forms of leishmaniasis and HIV co-infections are inadequate. In addition, full deployment of drugs in treatment and control requires defined strategies, which can also prevent or delay the development of drug resistance.

A Comparison of Miltefosine and Sodium Stibogluconate for Treatment of Visceral Leishmaniasis in an Ethiopian Population with High Prevalence of HIV Infection

BACKGROUND

Antimonials are the mainstay of visceral leishmaniasis (VL) treatment in Africa. The increasing incidence of human immunodeficiency virus (HIV) coinfection requires alternative safe and effective drug regimens. Oral miltefosine has been proven to be safe and effective in the treatment of Indian VL but has not been studied in Africa or in persons with HIV and VL coinfection.

METHODS

We compared the efficacy of miltefosine and sodium stibogluconate (SSG) in the treatment of VL in persons in Ethiopia. A total of 580 men with parasitologically and/or serologically confirmed VL were randomized to receive either oral miltefosine (100 mg per day for 28 days) or intramuscular SSG (20 mg/kg per day for 30 days).

RESULTS

The initial cure rate was 88% in both treatment groups. Mortality during treatment was 2% in the miltefosine group, compared with 10% in the SSG group. Initial treatment failure was 8% in the miltefosine group, compared with 1% in the SSG group. Among the 375 patients (65%) who agreed to HIV testing, HIV seroprevalence was 29%. Among patients not infected with HIV, initial cure, mortality, and initial treatment failure rates were not significantly different (94% vs. 95%, 1% vs. 3%, and 5% vs. 1% for the miltefosine and SSG groups, respectively). Initial treatment failure with miltefosine occurred in 18% of HIV-coinfected patients, compared with treatment failure in 5% of non-HIV-infected patients. At 6 months after treatment, 174 (60%) of the 290 miltefosine recipients and 189 (65%) of the 290 SSG recipients experienced cure; 30 (10%) of 290 in the miltefosine group and 7 (2%) of 290 in the SSG group experienced relapse, and the mortality rate was 6% in the miltefosine group, compared with 12% in the SSG group. HIV-infected patients had higher rates of relapse (16 [25%] of 63 patients), compared with non-HIV-infected patients (5 [5%] of 131).

CONCLUSIONS

Treatment with miltefosine is equally effective as standard SSG treatment in non-HIV-infected men with VL. Among HIV-coinfected patients, miltefosine is safer but less effective than SSG.

Treatment of visceral leishmaniasis

The Leishmania donovani complex includes L. chagasi and L. infantum, and causes visceral leishmaniasis (VL), a disseminated and potentially fatal form of leishmaniasis. The treatment options for VL are limited. Pentavalent antimonials (Sbv) are the first-line treatment options worldwide except for in Europe and Sbv-unresponsive regions of India. Amphotericin B deoxycholate is the drug of choice in India, as are its lipid formulations in Europe. However, liposomal amphotericin B (AmBisome, Gilead Sciences, Inc.) is the best antileishmanial formulation, but its prohibitive cost limits its use in endemic countries. Preferential pricing of AmBisome for patients with VL may provide hope for these underprivileged patients. Oral miltefosine and paromomycin are the other drugs that have been recently developed. Limited therapeutic options, the potential for development of resistance and serious toxicity associated with antileishmanial drugs necessitates a change in the treatment policy. A shift from monotherapy to multi-drug combinations of short courses delivered at no or affordable cost, through directly observed therapy, seems to be the only way to develop the treatment of this disease.

Leishmania donovani: effect of verapamil on in vitro susceptibility of promastigote and amastigote stages of Indian clinical isolates to sodium stibogluconate

Although pentavalent antimonials are the first-line drug for treatment of visceral leishmaniasis all over the world, yet, in India, increasing number of patients are being reported to be unresponsive to sodium stibogluconate. Verapamil, a calcium channel blocker, affects drug uptake by preventing its efflux and thereby accumulation within the cell. In the present study, effect of verapamil on in vitro susceptibility of both promastigote and amastigote stages of 15 clinical isolates and standard strain of Leishmania donovani to sodium stibogluconate was evaluated by detection of acid phosphatase. Amastigotes were found more susceptible to sodium stibogluconate than the promastigotes (p<0.05) and in the presence of verapamil, IC(50) value of sodium stibogluconate was reduced only for those isolates, which had a higher IC(50). Verapamil alone did not have any effect on the parasites. The results indicate that amastigotes are more susceptible to sodium stibogluconate than promastigotes and verapamil can reverse the in vitro drug resistance of L. donovani clinical isolates to sodium stibogluconate.

Drug resistance in leishmaniasis

Leishmaniasis is a complex disease, with visceral and cutaneous manifestations, and is caused by over 15 different species of the protozoan parasite genus Leishmania. There are significant differences in the sensitivity of these species both to the standard drugs, for example, pentavalent antimonials and miltefosine, and those on clinical trial, for example, paromomycin. Over 60% of patients with visceral leishmaniasis in Bihar State, India, do not respond to treatment with pentavalent antimonials. This is now considered to be due to acquired resistance. Although this class of drugs has been used for over 60 years for leishmaniasis treatment, it is only in the past 2 years that the mechanisms of action and resistance have been identified, related to drug metabolism, thiol metabolism, and drug efflux. With the introduction of new therapies, including miltefosine in 2002 and paromomycin in 2005-2006, it is essential that there be a strategy to prevent the emergence of resistance to new drugs; combination therapy, monitoring of therapy, and improved diagnostics could play an essential role in this strategy.

Electrocardiographic and biochemical adverse effects of sodium stibogluconate during treatment of cutaneous and mucosal leishmaniasis among returned travellers

Use of parenteral pentavalent antimonials to treat leishmaniasis is associated with a range of cardiological, biochemical and haematological adverse effects. The most serious of these is the development of ventricular tachyarrhythmias associated with prolongation of the electrocardiographic rate-corrected QT interval (QTc). Whereas some studies have reported that serious cardiological and biochemical adverse effects are common and often require treatment interruption or discontinuation, others have reported the drugs to be well tolerated. We conducted a detailed retrospective analysis of adverse events among British returned travellers (n=65) with New World cutaneous or mucosal leishmaniasis who received i.v. sodium stibogluconate (SbV) for >or=21 days. The mean+/-SEM QTc progressively increased from 389+/-3.1 msec to 404+/-2.9 msec during 3 weeks of treatment and the QTc reached the threshold for potential cardiac toxicity among 6 (10%) patients during the third week of treatment. Marked QTc prolongation and ventricular tachyarrhythmias occurred in one elderly patient with hypokalaemia and pre-existing cardiovascular morbidity. Although increased serum concentrations of amylase and hepatic transaminases were observed among 67% and 85% of patients respectively, none developed clinical pancreatitis or hepatitis and treatment modification was not required. SbV can be used safely in this population with adequate monitoring and the need for treatment interruption is uncommon. Identification of factors before and during treatment that may increase the risk of QTc prolongation and arrhythmias is important.

Treatment options for visceral leishmaniasis: a systematic review of clinical studies done in India, 1980-2004

The state of Bihar in India carries the largest share of the world's burden of antimony-resistant visceral leishmaniasis. We analysed clinical studies done in Bihar with different treatments between 1980 and 2004. Overall, 53 studies were included (all but one published), of which 15 were comparative (randomised, quasi-randomised, or non-randomised), 23 dose-finding, and 15 non-comparative. Data from comparative studies were pooled when appropriate for meta-analysis. Overall, these studies enrolled 7263 patients in 123 treatment arms. Adequacy of methods used to do the studies and report on them varied. Unresponsiveness to antimony has developed steadily in the past to such an extent that antimony must now be replaced, despite attempts to stop its progression by increasing dose and duration of therapy. The classic second-line treatments are unsuited: pentamidine is toxic and its efficacy has also declined, and amphotericin B deoxycholate is effective but requires hospitalisation for long periods and toxicity is common. Liposomal amphotericin B is very effective and safe but currently unaffordable because of its high price. Miltefosine-the first oral drug for visceral leishmaniasis-is now registered and marketed in India and is effective, but should be used under supervision to prevent misuse. Paromomycin (or aminosidine) is effective and safe, and although not yet available, a regulatory submission is due soon. To preserve the limited armamentarium of drugs to treat visceral leishmaniasis, drugs should not be deployed unprotected; combinations can make drugs last longer, improve treatment, and reduce costs to households and health systems. India, Bangladesh, and Nepal agreed recently to undertake measures towards the elimination of visceral leishmaniasis. The lessons learnt in Bihar could help inform policy decisions both regionally and elsewhere.

Production and characterization of stable amphotericin-resistant amastigotes and promastigotes of Leishmania mexicana

The sensitivities of Leishmania mexicana amastigote and promastigote forms to amphotericin B were investigated in vitro and found to be strongly influenced by the culture media used. When differences in culture media were minimized, there was no significant difference in the 50% inhibitory concentration values between the two life cycle stages. Stable amphotericin B-resistant amastigote and promastigote lines were produced by the application of increasing drug pressure to long-term cultures. Lines capable of growth in concentrations of amphotericin B lethal to normal parasites were produced. Compared to normal parasites, these amphotericin-resistant lines showed marked differences in membrane sterol compositions, with very high levels of 4,14,dimethyl-cholesta-8,24-dienol and other methyl sterols. They also showed a consistent morphological feature, the presence of multilamellar membrane-like material in the flagellar pocket, revealed by transmission electron microscopy. Amphotericin-resistant parasites were capable of infecting BALB/c mice, but the resulting lesion growth was slower than that after infection with normal parasites. However, unlike normal parasites, the amphotericin-resistant parasites were unaffected by experimental chemotherapy with amphotericin B. These results show that amphotericin B resistance could arise as a result of increased clinical use of amphotericin B therapy.

Antimony-induced cardiomyopathy in guinea-pig and protection by L-carnitine

Antimony (Sb) is the mainstay for the treatment of Leishmaniasis. It has serious, often lethal, cardiovascular side effects. The objective of this study was to examine the effects of Sb treatment upon the electrocardiogram (ECG), myocyte contractility (assessed by monitoring sarcomere length during field stimulation), whole-cell action potential (AP) and calcium current (I(Ca)) of the guinea-pig and to evaluate L-carnitine as a cardioprotective agent. Guinea-pigs received daily injections of either saline, Sb(V), Sb(III), L-carnitine or L-carnitine with Sb(III). Eight lead ECGs were recorded under halothane anaesthesia every 4 days. At the end of each treatment regime, animals were killed and ventricular myocytes were enzymatically isolated. Treatment with Sb(V) for 26 days prolonged the QT interval of the ECG. Treatment with Sb(III) was lethal within 2 days for approximately 50% of the animals. The survivors showed ECG alterations similar to those described in man: T wave flattening and/or inversion, depression of the ST segment, and elongation of RR and QT intervals. Their ventricular myocytes showed impaired contraction responses to changes in stimulus frequency, elongated AP and reduced I(Ca). Combined treatment with L-carnitine and Sb(III) delayed mortality. Prior treatment with L-carnitine followed by combined treatment with L-carnitine and Sb(III) reduced mortality to <10% over 12 days and these animals showed normal ECG. Their myocytes showed normal contractility and AP. It is concluded that L-carnitine has a preventive cardioprotective role against antimony-induced cardiomyopathy. The mechanism of action of L-carnitine may be to counter oxidative stress caused by Sb(III).

Combination therapy using sodium antimony gluconate in stearylamine-bearing liposomes against established and chronic Leishmania donovani infection in BALB/c Mice

In this work we report the activity seen with combination therapy using sodium antimony gluconate in liposomes composed of egg phosphatidyl choline and stearylamine for elimination of Leishmania donovani parasites from the liver and spleen of BALB/c mice with established and chronic infections.

Cloning of S-adenosyl-L-methionine:C-24-Delta-sterol-methyltransferase (ERG6) from Leishmania donovani and characterization of mRNAs in wild-type and amphotericin B-Resistant promastigotes

The 24-alkylated sterols have been shown previously to be absent in membranes of amphotericin B (AmB)-resistant Leishmania donovani promastigotes, suggesting that the S- adenosyl-l-methionine:C-24-Delta-sterol-methyltransferase (SCMT or ERG6) was not functional or not expressed in AmB-resistant (AmB-R) parasites. From an L. donovani wild-type clone, we cloned two cDNAs with an identical open reading frame encoding a putative SCMT, the enzyme responsible for a first sterol methylation at the C-24 position. The two cDNAs differed by their 3'-untranslated region (3'-UTR) and 5'-UTR sequences. One transcript (A) had a normal structure with a spliced leader and was highly expressed in normal cells but absent in AmB-R cells. The other (B), which did not possess the spliced leader sequence, was weakly expressed in normal cells but strongly expressed in AmB-R cells. As a functional test, ERG6 null mutant Saccharomyces cerevisiae yeasts were transformed using the pYES2.1 TOPO TA expression vector containing the candidate SCMT1/ERG6 coding sequence cloned from L. donovani. The transformed yeasts exhibited C-24 alkylated sterol expression, mainly ergosterol, within their membranes, proving that the isolated cDNA encodes on a SCMT responsible for sterol methylation. In AmB-R L. donovani promastigotes, the absence of the normal transcript (A) and the expression of an abnormal species (B) devoid of a spliced leader could explain the absence of sterol methylation in these cells. Further studies using a homologous system will allow us to draw conclusions about the relationship between SCMT expression and AmB resistance in Leishmania.

Skewing of cytokine profiles towards T helper cell type 2 response in visceral leishmaniasis patients unresponsive to sodium antimony gluconate

Thirty-two parasitologically confirmed visceral leishmanisis (VL) patients and 23 healthy, age- and gender-matched controls were recruited between April 2001 and March 2002 and studied for intracellular cytokine production after stimulation in vitro using a Fluorescence Activated Cell Sorter-based intracellular cytokine assay. The VL patients were given i.m. sodium antimony gluconate at a dose of 20 mg/kg bodyweight daily for 28 d and were grouped as responders (n = 11) or non-responders (no response after 28 d of treatment; n = 21). Clinically, the non-responders had longer duration of illness (P < 0.05), larger spleen size (P < 0.05), and higher parasite load (P < 0.05) than responders. The percentage of T helper (Th) cells producing interferon-gamma (IFN-gamma) was significantly higher (P < 0.001) in responders than non-responders. Non-responders had higher IFN-gamma production than control subjects (P < 0.001). The percentage of Th cells producing interleukin-4 (IL-4) was significantly higher in non-responders than responders (P = 0.003) as well as in healthy subjects (P < 0.001). The frequency of IL-4 producing cells in responders and control subjects was similar (P= 0.65). The cytokine polarization index, as calculated by the formula loge IFN-gamma producing cells/loge IL-4 producing cells, was significantly lower in non-responders compared with both responders and control subjects (P = 0.003 and P < 0.001, respectively). The overall cytokine bias in non-responders was skewed towards a IL-4 dominance or Th2-like response and this was primarily due to induction of IL-4.

Anilino-(2-bromophenyl) acetonitrile: a promising orally effective antileishmanial agent

Visceral leishmaniasis (VL) or kala-azar is a worldwide disseminated intracellular infection caused by the hemoflagellate protozoan parasites Leishmania donovani. Chemotherapeutic scenario presents a deplorable picture and demands an urgent search for a new and safe anti-VL drugs, preferably active by oral route. In search of new antileishmanial agents, a total of 16 compounds belonging to the anilino-(substituted phenyl)-acetonitrile class were tested in vitro in promastigote/macrophase-amastigote systems and in vivo in L. donvoani/hamster model for their antileishmanial activity. Compound 3, anilino-(2-bromophenyl)-acetonitrile, exhibited most promising activity both in vitro at a concentration of 100 microg/ml (82.33 and 94.36% in promastigote and macrophase-amastigote systems, respectively) and in vivo at a dose of 50 mg/kg for 5 days (82.11 and 80% by i.p. and p.o. routes, respectively), hence this compound was investigated in detail. To maximize its bioavailability, dissolution profile, absorption, the compound was also tested in vivo as its soluble form. But no enhancement in activity was observed. From the results of different parameters for example ED(50) and LD(50) etc. compound 3 appears to be a potent orally effective compound which could further be investigated to establish its potential as a candidate molecule of antileishmanial therapy.

How better drugs could change kala-azar control. Lessons from a cost-effectiveness analysis

Conditional on correct diagnosis and treatment, current drug regimens for visceral leishmaniasis (VL) will only prevent about 90% of deaths. Furthermore, the cost of pentavalent antimonials, the long duration of the regimen and its parenteral administration are major obstacles for patients. Poor patient compliance and the use of counterfeit drugs contribute to therapeutic failure, amplification of the reservoir and the appearance of drug resistance. We assessed the impact of potential improvements in chemotherapy on the cost-effectiveness of VL test-treatment strategies. Competing test-treatment strategies were compared in a formal decision analysis - from the viewpoint of the clinician facing a VL suspect -, with avoided VL-mortality and cost as outcomes of interest. Sensitivity analysis was done involving the following parameters: efficacy, toxicity and cost of treatment including patient care. When safer and more efficacious drugs are considered, they only result in a more cost-effective strategy if the total cost of treatment falls below US$ 390 per patient. A serological test-treatment strategy remains the optimal choice, also when better drugs become available.

Activities of hexadecylphosphocholine (miltefosine), AmBisome, and sodium stibogluconate (Pentostam) against Leishmania donovani in immunodeficient scid mice

In both scid and BALB/c mouse-Leishmania donovani models, hexadecyphosphocholine (miltefosine) and AmBisome had similar levels of activity. In contrast, sodium stibogluconate (Pentostam) was significantly less active against L. donovani in scid mice than in BALB/c mice. The in vitro anti-leishmanial activity of miltefosine was similar in peritoneal macrophages derived from both scid and BALB/c mice, whereas Pentostam and AmBisome were significantly more active in the latter.

Treatment of visceral leishmaniasis (kala-azar): a decade of progress and future approaches

In 1990, there was essentially one treatment regimen in use for visceral leishmaniasis (kala-azar) around the world: 20 to 28 days of daily injections of pentavalent antimony (Sb). During the past 10 years, however, new agents have been tested alone or in combination, in more than 50 studies carried out worldwide. This renewed clinical effort was spurred by a variety of factors, including the emergence of large-scale Sb unresponsiveness in India, where up to one-half of the world's cases of kala-azar now are found. As this new decade opens, the success of this clinical research effort is tangible: three additional, highly effective parenteral regimens now are available (amphotericin B, lipid formulations of amphotericin B, aminosidine), and an active oral agent, a long sought after objective in kala-azar, has been identified (miltefosine). This report reviews the evolution of treatment of visceral leishmaniasis, considers the interaction of the immune response and chemotherapy, highlights therapeutic successes and failures, examines advantages and disadvantages of current treatments, and looks at future therapeutic approaches to the management of this disseminated intracellular protozoal infection.

Leishmania species, drug unresponsiveness and visceral leishmaniasis in Bihar, India

Sixteen isolates obtained, in January 1998-December 1999, from splenic aspirates from sodium stibogluconate-resistant cases of visceral leishmaniasis (VL; Indian kala-azar) and drawn from different districts of Bihar (India) were identified as Leishmania donovani. By isoenzyme analysis, all the strains were found identical to the WHO reference strain L. donovani MON-2 and differed from L. tropica MON-5. This study suggested that resistant cases of VL in Bihar were caused by L. donovani and not by L. tropica. No new strain responsible for drug unresponsiveness emerged during this period and other cause or causes of emergence of drug resistance should be sought. All the patients were cured with amphotericin B.

A single high dose treatment of kala-azar with Ambisome (amphotericin B lipid complex): a pilot study

Thirty four patients with parasitologically confirmed visceral leishmaniasis were divided randomly into two groups of 17. Group A received Ambisome (amphotericin B lipid complex) at a dose of 15mg/kg body weight infused over 2h as a single dose; patients in group B received amphotericin B deoxycholate at a dose of 1mg/kg body infused for 2h for 20days. All 34 patients had a clinical, parasitological and ultimate cure. Ambisome was much better tolerated than amphotericin B, and adverse events were fewer in the Ambisome group. It was concluded that, if the cost of Ambisome were reduced, it would be a suitable first line drug. A longer study comparing three regimes of Ambisome: 15mg/kg body weight, 11mg/kg body weight and 7.5mg/kg body weight, should be undertaken.

Failure of pentavalent antimony in visceral leishmaniasis in India: report from the center of the Indian epidemic

In India, 320 patients with visceral leishmaniasis (209 in the state of Bihar and 11 in the neighboring state of Uttar Pradesh) received identical pentavalent antimony (Sb) treatment. Sb induced long-term cure in 35% (95% confidence interval [CI], 28%-42%) of those in Bihar versus 86% (95% CI, 79%-93%) of those in Uttar Pradesh. In Bihar, the center of the Indian epidemic, traditional Sb treatment should be abandoned.

Short-course of oral miltefosine for treatment of visceral leishmaniasis

A total of 54 Indian patients with visceral leishmaniasis were treated with oral miltefosine, 50 mg given twice daily, for 14 days (18 patients; group A), 21 days (18; group B), or 28 days (18; group C). Cure was achieved in 89% of group A, 100% of group B, and 100% of group C. Adverse reactions were self-limited and primarily mild. The 21-day miltefosine regimen combines high-level efficacy, convenient dosing, and a relatively short duration.

A prospective randomized, comparative, open-label trial of the safety and efficacy of paromomycin (aminosidine) plus sodium stibogluconate versus sodium stibogluconate alone for the treatment of visceral leishmaniasis

Response to treatment with organic pentavalent antimonials, the standard first-line treatment for visceral leishmaniasis (VL), has been decreasing since their introduction into India. Combining sodium stibogluconate (SB) with paromomycin (PM) may be an efficient alternative to single-agent therapy. This trial was designed to assess the safety and efficacy of PM 12 or 18 mg/kg daily plus SB 20 mg/kg daily for 21 days compared to SB alone for 30 days. One hundred and fifty patients were randomly assigned in 1996 to 1 of the 3 treatments and followed-up for 180 days. At the end of treatment, 49 of 52 patients receiving PM12 + SB, 46 of 48 receiving PM18 + SB, and 27 of 49 patients receiving SB alone, were cured. During follow-up there was 1 relapse in each of the treatment groups, giving final cure rates of 48 of 52 (92.3%) for PM12 + SB, 45 of 48 (93.8%) for PM18 + SB, and 26 of 49 (53.1%) for SB. PM plus SB for 21 days at either 12 or 18 mg/kg daily was significantly more effective than SB alone for 30 days (chi 2 P < 0.001). One patient (SB alone) had experienced a serious adverse event: cardiotoxicity at day 8 (myocarditis and ECG changes) which caused withdrawal from the study. Only 19 of 100 patients enrolled in the PM treatment arms had a complete audiogram series conducted thus making it difficult to assess oto-toxicity. PM 12 or 18 mg/kg daily plus a standard dose of SB for 21 days was statistically more effective than SB in producing a final cure for patients with VL in Bihar, India.