Single-dose liposomal amphotericin B in the treatment of visceral leishmaniasis in India: a multicenter study

Liposomal amphotericin B and leishmaniasis: dose and response

Liposomal amphotericin B has been used with increasing frequency to treat visceral leishmaniasis (VL). It is the treatment of choice for immunocompetent patients in the Mediterranean region and the preferred drug for HIV/VL co-infection. Although there is a regional variation in the susceptibility of the parasite a total dose of 20 mg/kg is effective in immunocompetent patients. Randomized clinical trials of liposomal amphotericin B in the treatment and secondary prophylaxis of HIV-VL coinfected patients is urgently needed to optimize treatment in this subset. With the availability of Liposomal amphotericin B at a preferential pricing in the endemic areas, short course combination therapy can become a viable alternative.

Visceral leishmaniasis: elimination with existing interventions

The world's burden of infectious diseases can be substantially reduced by more-effective use of existing interventions. Advances in case detection, diagnosis, and treatment strategies have made it possible to consider the elimination of visceral leishmaniasis in the Indian subcontinent. The priority must now be to effectively implement existing interventions at the community level by actively finding cases in endemic villages and treating them with single-dose liposomal amphotericin B at primary-health-care centres. Once the elimination target of one case per 10,000 population has been reached, combination therapies involving miltefosine and paromomycin can be introduced to ensure long-term availability of several drugs for visceral leishmaniasis and to protect against resistance.

Leishmaniasis: new insights from an old and neglected disease

Leishmaniases are a clinically heterogeneous group of diseases caused by protozoa of the genus Leishmania. There is growing evidence that the true incidence of the disease is underestimated, especially in hyperendemic regions. Moreover, climate changes together with the increasing movement of humans and animals raise concerns about the possible introduction of Leishmania infection in previously spared areas. The disease is emerging in immunocompromised patients undergoing bone marrow or solid organ transplantation or treatment with biologic drugs. Furthermore, the deployment of military troops and travel to endemic areas are associated with the observation of a growing number of patients with cutaneous disease. Improvement in diagnostic methods, both in the field and in specialized laboratories, has been obtained through the implementation of molecular amplification methods and using the rK39 antigen as the substrate. Finally, new therapeutic approaches are gaining attention, such as the use of miltefosine for cutaneous leishmaniasis and paromomycin for visceral leishmaniasis, as well as the use of various antileishmanial drugs in combination.

Renal involvement in leishmaniasis: a review of the literature

Leishmaniasis, an infectious disease endemic in tropical, Asian and southern European countries, is caused by obligate intramacrophage protozoa and is transmitted through the bite of infected female sandflies. More than 20 leishmanial species are responsible for four main clinical syndromes: cutaneous leishmaniasis; mucocutaneous leishmaniasis; visceral leishmaniasis, also known as kala-azar, and post-kala-azar dermal leishmaniasis. Visceral leishmaniasis can present with varying clinical features and the kidney can also be involved. Both glomerular and tubular function can be altered and patients can develop proteinuria, haematuria, abnormalities in urinary concentration and acidification and acute and chronic renal insufficiency. Not only the disease itself but also the therapy administered might be responsible for the renal involvement in kala-azar. Indeed, some of the agents with efficiency against visceral leishmaniasis, such as pentavalent antimonial drugs, amphotericin B, pentamidine, miltefosine, paromomycin and simataquine, may be associated with a high risk of renal toxicity. In this article, the literature on renal involvement in visceral leishmaniasis is reviewed.

Structures, targets and recent approaches in anti-leishmanial drug discovery and development

Recent years have seen a significant improvement in available treatment options for leishmaniasis. Two new drugs, miltefosine and paromomycin, have been registered for the treatment of visceral leishmaniasis (VL) in India since 2002. Combination therapy is now explored in clinical trials as a new treatment approach for VL to reduce the length of treatment and potentially prevent selection of resistant parasites. However there is still a need for new drugs due to safety, resistance, stability and cost issues with existing therapies. The search for topical treatments for cutaneous leishmaniasis (CL) is ongoing. This review gives a brief overview of recent developments and approaches in anti-leishmanial drug discovery and development.

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

BACKGROUND

AmBisome® is an efficacious, safe anti-leishmanial treatment. There is growing interest in its use, either as a single dose or in combination treatments. In East Africa, the minimum optimal single-dosage has not been identified.

METHODS/DESIGN

An open-label, 2-arm, non-inferiority, multi-centre randomised controlled trial is being conducted to determine the optimal single-dose treatment with AmBisome®.Patients in the single-dose arm will receive one infusion on day 1, at a dose depending on body weight. For the first group of patients entered to the trial, the dose will be 7.5 mg/kg, but if this dose is found to be ineffective then in subsequent patient series the dose will be escalated progressively to 10, 12.5 and 15 mg/kg. Patients in the reference arm will receive a multi-dose regimen of AmBisome® (3 mg/kg/day on days 1-5, 14 and 21: total dose 21 mg/kg). Patients will be hospitalised for approximately one month after the start of treatment and then followed up at three and six months. The primary endpoint is the status of patients six months after treatment. A secondary endpoint is assessment at day 30. Treatment success is determined as the absence of parasites on microscopy samples taken from bone marrow, lymph node or splenic aspirates. Interim analyses to assess the comparative efficacy of the single dose are planned after recruitment of 20 and 40 patients per arm. The final non-inferiority analysis will include 120 patients per arm, to determine if the single-dose efficacy 6 months after treatment is not more than 10% inferior to the multi-dose.

DISCUSSION

An effective, safe single-dose treatment would reduce hospitalization and treatment costs. Results will inform the design of combination treatment studies.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00832208.

Cyclic-nucleotide signalling in protozoa

Compared with the impressive progress in understanding signal transduction pathways and mechanisms in mammalian systems, advances in protozoan signalling processes, including cyclic nucleotide metabolism, have been very slow. This is in large part connected to the fact that the components of these pathways are very different in the protozoan parasites, as confirmed by the recently completed genome. For instance, kinetoplastids have no equivalents to the mammalian Class I adenylyl cyclases (ACs) in their genomes nor any of the subunits of the associated G-proteins. The cyclases in kinetoplastid parasites contain a single transmembrane domain, a conserved intracellular catalytic domain and a highly variable extracellular domain - consistent with the expression of multiple receptor-activated cyclases - but no receptor ligands, agonists or antagonists have been identified. Apicomplexan AC and guanylyl cyclase (GC) are even more unusual, potentially being bifunctional, harbouring either a putative ion channel (AC) or a P-type ATPase-like domain (GC) alongside the catalytic region. Phosphodiesterases (PDEs) and cyclic-nucleotide-activated protein kinases are essentially conserved in protozoa, although mostly insensitive to inhibitors of the mammalian proteins. Some of the PDEs have now been validated as promising drug targets. In the following manuscript, we will summarize the existing literature on cAMP and cGMP in protozoa: cyclases, PDEs and cyclic-nucleotide-dependent kinases.

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.

Drug delivery strategies for therapy of visceral leishmaniasis

IMPORTANCE OF THE FIELD

Visceral leishmaniasis (VL) is the most overwhelming type of leishmaniasis associated with the poverty of developing countries and usually mortal if untreated. Most of the conventionally used dosage forms offer us the shortcomings of toxic side effects and emergence of drug resistance. Several efforts have been made to overcome the barriers involved in the treatment of VL. Colloidal carriers extensively represent the drug delivery systems (DDSs) for intracellular localization of antileishmanial compounds in macrophage-rich organs such as liver, spleen and bone marrow. These DDSs offer superior therapeutic efficacy over the conventional treatment in terms of site-specific drug delivery with reduced side effects. However, after 35 years of research in the field, AmBisome (Amphotericin B liposome for injection, Astellas Pharma US, Inc.) is the only DDS used against the VL.

AREAS COVERED IN THIS REVIEW

A literature search was performed (for drugs and DDSs against VL) on PubMed and through Google.

WHAT THE READER WILL GAIN

This review aims to describe the pathophysiology of VL and its current conventional treatment with special reference to DDSs designed against VL.

TAKE HOME MESSAGE

On reviewing the conventional drugs and DDSs developed against VL, it is concluded that advances in the field of targeted drug delivery can result in more efficient strategies for the therapy of VL.

Single-dose liposomal amphotericin B for visceral leishmaniasis in India

BACKGROUND

Some 50% of patients with visceral leishmaniasis (kala-azar) worldwide live in the Indian state of Bihar. Liposomal amphotericin B is an effective treatment when administered in short courses. We wanted to determine whether the efficacy of a single infusion of liposomal amphotericin B was inferior to conventional parenteral therapy, consisting of 15 alternate-day infusions of amphotericin B deoxycholate.

METHODS

In this open-label study, we randomly assigned 412 patients in a 3:1 ratio to receive either liposomal amphotericin B (liposomal-therapy group) or amphotericin B deoxycholate (conventional-therapy group). Liposomal amphotericin B (at a dose of 10 mg per kilogram of body weight) was given once, and patients were discharged home 24 hours later. Amphotericin B deoxycholate, which was administered in 15 infusions of 1 mg per kilogram, was given every other day during a 29-day hospitalization. We determined the cure rate 6 months after treatment.

RESULTS

A total of 410 patients--304 of 304 patients (100%) in the liposomal-therapy group and 106 of 108 patients (98%) in the conventional-therapy group--had apparent cure responses at day 30. Cure rates at 6 months were similar in the two groups: 95.7% (95% confidence interval [CI], 93.4 to 97.9) in the liposomal-therapy group and 96.3% (95% CI, 92.6 to 99.9) in the conventional-therapy group. Adverse events in the liposomal-therapy group were infusion-related fever or rigors (in 40%) and increased anemia or thrombocytopenia (in 2%); such events in the conventional-therapy group were fever or rigors (in 64%), increased anemia (in 19%), and hypokalemia (in 2%). Nephrotoxicity or hepatotoxicity developed in no more than 1% of patients in each group.

CONCLUSIONS

A single infusion of liposomal amphotericin B was not inferior to and was less expensive than conventional therapy with amphotericin B deoxycholate. (ClinicalTrials.gov number, NCT00628719.)

Role of nanocarrier systems in cancer nanotherapy

Cancer continues to be a major cause of morbidity and mortality worldwide. While discovery of new drugs and cancer chemotherapy opened a new era for the treatment of tumors, optimized concentration of drug at the target site is only possible at the expense of severe side effects. Nanoscale carrier systems have the potential to limit drug toxicity and achieve tumor localization. When linked with tumor-targeting moieties, such as tumor-specific ligands or monoclonal antibodies, the nanocarriers can be used to target cancer-specific receptors, tumor antigens, and tumor vasculatures with high affinity and precision. This article is an overview of advances and prospects in the applications of nanocarrier technology in cancer therapy. Applications of nanoliposomes, dendrimers, and nanoparticles in cancer therapy are explained, along with their preparation methods and targeting strategies.

N-(2-hydroxypropyl)methacrylamide-amphotericin B (HPMA-AmB) copolymer conjugates as antileishmanial agents

Leishmaniasis is a major health problem in many parts of the world, caused by various species of Leishmania. Amastigotes are the clinically relevant form of the parasite in the human host and reside in the parasitophorous vacuole within macrophages. Polymer-drug conjugates have been used for lysosomotropic drug delivery and have already shown potential in anticancer and antileishmanial chemotherapy. We synthesised N-(2-hydroxypropyl)methacrylamide-amphotericin B (HPMA-AmB) copolymer conjugates in which the AmB was attached to the polymer through a degradable GlyPheLeuGly linker. Antileishmanial activity was assessed in vitro against intracellular amastigotes in host macrophages [murine peritoneal exudate macrophages (PEMs), murine bone marrow-derived macrophages (BMMs) and differentiated THP-1 cells]. The most potent copolymers had 50% effective concentration (EC(50)) values of 0.03 microg/mL AmB equivalent against Leishmania donovani amastigotes in PEMs and BMMs and an EC(50) of 0.57 microg/mL AmB equivalent against L. donovani in THP-1 cells. This activity was comparable with free AmB (EC(50)=0.03-0.07 microg/mL against L. donovani in PEMs and BMMs and 0.24-0.42 microg/mL against amastigotes in THP-1 cells) and Fungizone (EC(50)=0.04-0.07 microg/mL against amastigotes in PEMs). Conjugates also showed potent in vivo activity with ca. 50% inhibition of parasite burden at 1mg/kg body weight.

Kinetoplastids: related protozoan pathogens, different diseases

Kinetoplastids are a group of flagellated protozoans that include the species Trypanosoma and Leishmania, which are human pathogens with devastating health and economic effects. The sequencing of the genomes of some of these species has highlighted their genetic relatedness and underlined differences in the diseases that they cause. As we discuss in this Review, steady progress using a combination of molecular, genetic, immunologic, and clinical approaches has substantially increased understanding of these pathogens and important aspects of the diseases that they cause. Consequently, the paths for developing additional measures to control these "neglected diseases" are becoming increasingly clear, and we believe that the opportunities for developing the drugs, diagnostics, vaccines, and other tools necessary to expand the armamentarium to combat these diseases have never been better.

Nanotechnology: a focus on nanoparticles as a drug delivery system

This review will provide an in-depth discussion on the previous development of nanoparticle-based drug delivery systems (DDS) and discuss original research data that includes the therapeutic enhancement of antiretroviral therapy. The use of nanoparticle DDS will allow practitioners to use drugs to target specific areas of the body. In the treatment of malignancies, the use of nanoparticles as a DDS is making measurable treatment impact. Medical imaging will also utilize DDS to illuminate tumors, the brain, or other cellular functions in the body. The utility of nanoparticle DDS to improve human health is potentially enormous.

pH-sensitive liposomes--principle and application in cancer therapy

The purpose of this review is to provide an insight into the different aspects of pH-sensitive liposomes. The review consists of 6 parts: the first introduces different types of medications made in liposomal drug delivery to overcome several drawbacks; the second elaborates the development of pH-sensitive liposomes; the third explains diverse mechanisms associated with the endocytosis and the cytosolic delivery of the drugs through pH-sensitive liposomes; the fourth describes the role and importance of pH-sensitive lipid dioleoylphosphatidylethanolamine (DOPE) and research carried on it; the fifth explains successful strategies used so far using the mechanism of pH sensitivity for fusogenic activity; the final part is a compilation of research that has played a significant role in emphasizing the success of pH-sensitive liposomes as an efficient drug delivery system in the treatment of malignant tumours. pH-Sensitive liposomes have been extensively studied in recent years as an amicable alternative to conventional liposomes in effectively targeting and accumulating anti-cancer drugs in tumours. This research suggests that pH-sensitive liposomes are more efficient in delivering anti-cancer drugs than conventional and long-circulating liposomes due to their fusogenic property. Research focused on the clinical and therapeutic side of pH-sensitive liposomes would enable their commercial utility in cancer treatment.

Leishmaniasis

Epidemiology, disease patterns, immunology, diagnosis, treatment and control measures of leishmaniasis are described. Various issues relating to leishmaniasis are highlighted: the relative lack of importance given to this disease compared with other infections, climate change and its possible impact on extension of endemicity of this infection, and new diagnostic tests which are improving diagnosis, especially in resource poor areas. Other important aspects discussed include the potential for newer oral therapy to change the way this disease is managed; Leishmania-HIV coinfection and groups at risk; and development of an effective vaccine.

Leishmaniasis

Epidemiology, disease patterns, immunology, diagnosis, treatment and control measures of leishmaniasis are described. Various issues relating to leishmaniasis are highlighted: the relative lack of importance given to this disease is compared with other infections, climate change and its possible effect on extension of endemicity of this infection, and new diagnostic tests that are helping better diagnosis, especially in resource-poor areas. Other important aspects discussed include the potential for newer oral treatment to change the way this disease is managed; leishmania-HIV coinfection and groups at risk; and the development of an effective vaccine.

Liposomal amphotericin B for the treatment of visceral leishmaniasis

During the past decade, liposomal amphotericin B has been used with increasing frequency to treat visceral leishmaniasis (VL). The World Health Organization convened a workshop to review current knowledge and to develop guidelines for liposomal amphotericin B use for VL. In Europe, liposomal amphotericin B is widely used to treat VL. In Africa and Asia, the VL disease burden is high and drug access is poor; liposomal amphotericin B is available only through preferential pricing for nonprofit groups in East Africa. Clinical trials and experience demonstrate high efficacy and low toxicity for liposomal amphotericin B (total dose, 20 mg/kg) in immunocompetent patients with VL. Combination trials in areas with antileishmanial drug resistance, and treatment and secondary prophylaxis trials in VL-human immunodeficiency virus-coinfected patients, are important to safeguard the current armamentarium and to optimize regimens. The public health community should work to broaden access to preferential liposomal amphotericin B pricing by public sector VL treatment programs.

Treatment options for visceral leishmaniasis

This review summarizes the current developments in therapy for visceral leishmaniasis. With the recent introduction of new drugs, the main limits in reducing deaths from visceral leishmaniasis are difficulty in diagnosis in the field and health inequality--patients lack of access to treatment. No new drugs are currently in the early stages of development. There are good reasons for the use of combination therapy; to prevent further development of resistance against the limited therapeutic options available.

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.

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.

Liposomal amphotericin B: clinical experience and perspectives

While amphotericin B deoxycholate (Fungizone, Apothecon Pharmaceuticals) has been considered by many to be the gold standard for the treatment for numerous invasive fungal infections for over 45 years, toxicities associated with its use often necessitate treatment modification or discontinuation. Lipid-based formulations, including liposomal amphotericin B (AmBisome, Fujisawa Healthcare, Inc.), were developed to decrease many of these toxicities while retaining broad antifungal spectrum and potency of amphotericin B. In clinical trials, liposomal amphotericin B has demonstrated efficacy comparable to that of amphotericin B deoxycholate while reducing the incidence of treatment-related nephrotoxicity, electrolyte-wasting, and infusion-related reactions. In addition, recent clinical trials have also compared liposomal amphotericin B with other antifungal classes. Acquisition costs of liposomal amphotericin B are substantially higher than those of amphotericin B deoxycholate and other antifungals. While pharmacoeconomic analyses consider outcomes and other treatment-related costs, they have yet to clearly demonstrate the cost-effectiveness of liposomal amphotericin B when compared with amphotericin B deoxycholate or other antifungal agents. This review will focus primarily on recent liposomal amphotericin B experience and attempt to put its use into perspective considering other available antifungal agents.

Amphotericin B Colloidal Dispersion for the Treatment of Indian Visceral Leishmaniasis

BACKGROUND

In Bihar, India, where visceral leishmaniasis (VL) is hyperendemic and refractory to antimony, amphotericin B is the most effective option for the treatment of VL. Lipid formulations of amphotericin B are able to circumvent the toxic effect of conventional amphotericin B, and the total dose of these formulations can be administered over a short duration. However, cost is a major constraint in the use of lipid formulations of amphotericin B. Amphotericin B colloidal dispersion (ABCD), which is a less expensive lipid formulation, has not been tested for the treatment of VL in India.

METHODS

In an open-label, randomized clinical trial, we evaluated the efficacy and safety of a 6-day course of ABCD administered to 3 different dose groups (total dose: 7.5 mg/kg [group A], 10 mg/kg [group B], and 15 mg/kg [group C]), each of which included a cohort of 135 patients.

RESULTS

Although infusion-related fever and chills occurred in 56%-68% of patients in the 3 different dose groups, 401 of 405 patients completed the treatment. All 135 patients in group A completed treatment, and the final cure rate for this group was 97%. In the group that received the highest dose of ABCD (group C), severe backache, an unusual side effect, was observed in 8 patients (5.92%). Serious adverse effects led to the withdrawal of 2 patients (1.48%) each from group B and group C.

CONCLUSIONS

Although the cost of ABCD is prohibitive, the high level of efficacy associated with short-term treatment with low-dose ABCD provides another alternative for the treatment of VL, especially in regions where VL is antimony refractory.

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.

Advances in leishmaniasis

Governed by parasite and host factors and immunoinflammatory responses, the clinical spectrum of leishmaniasis encompasses subclinical (inapparent), localised (skin lesions), and disseminated infection (cutaneous, mucosal, or visceral). Symptomatic disease is subacute or chronic and diverse in presentation and outcome. Clinical characteristics vary further by endemic region. Despite T-cell-dependent immune responses, which produce asymptomatic and self-healing infection, or appropriate treatment, intracellular infection is probably life-long since targeted cells (tissue macrophages) allow residual parasites to persist. There is an epidemic of cutaneous leishmaniasis in Afghanistan and Pakistan and of visceral infection in India and Sudan. Diagnosis relies on visualising parasites in tissue or serology; culture and detection of parasite DNA are useful in the laboratory. Pentavalent antimony is the conventional treatment; however, resistance of visceral infection in India has spawned new treatment approaches--amphotericin B and its lipid formulations, injectable paromomycin, and oral miltefosine. Despite tangible advances in diagnosis, treatment, and basic scientific research, leishmaniasis is embedded in poverty and neglected. Current obstacles to realistic prevention and proper management include inadequate vector (sandfly) control, no vaccine, and insufficient access to or impetus for developing affordable new drugs.

Leishmaniasis as an opportunistic infection in HIV-infected patients: determinants of relapse and mortality in a collaborative study of 228 episodes in a Mediterreanean region

The clinical presentation of visceral leishmaniasis shares similarities with other geographically specific infectious diseases associated with AIDS in terms of relapsing course and atypical presentation. However, visceral leishmaniasis has not, until now, been included in the AIDS case definition. The aim of this study was to describe the clinical features and determinants for relapse and case-fatality of visceral leishmaniasis in HIV-infected patients from a Spanish Mediterranean area. A chart review was conducted in 16 hospitals in the autonomous communities of Valencia and Murcia (Spain). From 1988 to 2001, a total of 228 episodes of visceral leishmaniasis were diagnosed in 155 HIV-infected patients by the detection of amastigotes in bone marrow aspirates or in other tissue samples. Most patients had advanced HIV disease, with a median CD4(+) lymphocyte cell count of 55 cells x 10(9) l, and 56% of them had a previous AIDS-indicator disease. The median duration of follow-up was 8.4 months. HIV-infected patients with visceral leishmaniasis presented with fever (76%), hepatomegaly (77%), splenomegaly (78%), and varying degrees of cytopenias. Leishmania was detected in atypical sites in 22 (14%) patients. A total of 37 (24%) patients had a relapse of visceral leishmaniasis. Female gender was a risk factor for relapse, whereas administration of secondary prophylaxis for visceral leishmaniasis and a completed therapy for visceral leishmaniasis were protective factors against relapse. A total of 86 (54%) patients died. Independent determinants for survival were CD4(+) lymphocyte cell count, completed therapy for leishmania, and secondary prophylaxis for visceral leishmaniasis. The findings show that, in HIV-infected patients, visceral leishmaniasis occurs in late stages of HIV disease and often has a relapsing course. Secondary prophylaxis reduces the risk of relapse. Visceral leishmaniasis in the HIV-infected population should be included in the CDC clinical category C for the definition of AIDS in the same way that other geographically specific opportunistic infections are included.

Visceral leishmaniasis: new health tools are needed

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

Recent advances with liposomes as pharmaceutical carriers

Liposomes - microscopic phospholipid bubbles with a bilayered membrane structure - have received a lot of attention during the past 30 years as pharmaceutical carriers of great potential. More recently, many new developments have been seen in the area of liposomal drugs - from clinically approved products to new experimental applications, with gene delivery and cancer therapy still being the principal areas of interest. For further successful development of this field, promising trends must be identified and exploited, albeit with a clear understanding of the limitations of these approaches.

Alternative dosing regimens of liposomal amphotericin B (AmBisome) effective in treating murine systemic candidiasis

OBJECTIVES

This study was done to determine whether high dose AmBisome (4-20 mg/kg), given intermittently, could reduce the frequency of dosing needed to treat murine systemic candidiasis when compared with conventional daily treatment.

METHODS

Mice were immunosuppressed with cyclophosphamide every 3 days, beginning day -3 before challenge with log(10) 5.0 cfu Candida albicans. Treatment was begun 48-72 h post-challenge with daily or intermittent dose regimens of AmBisome, followed by determination of kidney cfu for up to 1 month post-treatment.

RESULTS

A single AmBisome dose of 4 mg/kg was as effective as four daily, 1 mg/kg treatments. A total of 8 mg/kg, given as 4 mg/kg on days 2 and 4, or as 5 mg/kg on day 2 followed by 1 mg/kg on days 3, 4, and 5, also produced comparable efficacy. While 20 mg/kg given day 2, 4 and 6 post-challenge as a 1 week loading dose, followed by one 10 mg/kg treatment on day 13, decreased the fungal burden by up to 5 logs compared with controls (log(10) 2.3 cfu/g and log(10) 7.5 cfu/g, respectively), 20 mg/kg given Monday, Wednesday and Friday for 5 weeks, reduced the fungal burden to undetectable levels (i.e. log(10) 1.0 cfu).

CONCLUSIONS

Significant reduction or clearance of kidney cfu, following intermittent, high dose AmBisome treatment, indicated that non-daily dosing regimens could be successfully used instead of conventional daily dosing to treat established C. albicans infection in immunosuppressed mice.

Efficacy and Tolerability of Miltefosine for Childhood Visceral Leishmaniasis in India

Miltefosine has previously been shown to cure 97% of cases of visceral leishmaniasis (VL) in Indian adults. Because approximately one-half of cases of VL occur in children, we evaluated use of the adult dosage of miltefosin (2.5 mg/kg per day for 28 days) in 80 Indian children (age, 2-11 years) with parasitologically confirmed infection in an open-label clinical trial. Clinical and parasitological parameters were reassessed at the end of treatment and 6 months later. One patient died of intercurrent pneumonia on day 6. The other 79 patients demonstrated no parasites after treatment, had marked clinical improvement, and were deemed initially cured. Three patients had relapse, and 1 patient was lost to follow-up. The final cure rate was 94% for all enrolled patients and 95% for evaluable patients. Side effects included mild-to-moderate vomiting or diarrhea (each in approximately 25% of patients) and mild-to-moderate, transient elevations in the aspartate aminotransferase level during the early treatment phase (in 55%). This trial indicates that miltefosine is as effective and well tolerated in Indian children with VL as in adults and that it can be recommended as the first choice for treatment of childhood VL in India.