Oral miltefosine for Indian visceral leishmaniasis

Visceral leishmaniasis clinical management in endemic districts of India, Nepal, and bangladesh

Background. National VL Elimination Programs in India, Nepal and Bangladesh face challenges as home-based Miltefosine treatment is introduced. Objectives. To study constraints of VL management in endemic districts within context of national elimination programs before and after intervention. Methods. Ninety-two and 41 newly diagnosed VL patients were interviewed for clinical and provider experience in 2009 before and in 2010 after intervention (district training and improved supply of diagnostics and drugs). Providers were assessed for adherence to treatment guidelines. Facilities and doctor-patient consultations were observed to assess quality of care. Results. Miltefosine use increased from 33% to 59% except in Nepal where amphotericin was better available. Incorrect dosage and treatment interruptions were rare. Advice on potential side effects was uncommon but improved significantly in 2010. Physicians did not rule out pregnancy prior to starting Miltefosine. Fever measurement or spleen palpation was infrequently done in Bangladesh but improved after intervention (from 23% to 47%). Physician awareness of renal or liver toxicity as Miltefosine side effects was lower in Bangladesh. Bio-chemical monitoring was uncommon. Patient satisfaction with services remained low for ease of access or time provider spent with patient. Health facilities were better stocked with rK39 kits and Miltefosine in 2010.

Miltefosine and cutaneous leishmaniasis

PURPOSE OF REVIEW

Miltefosine is a new oral treatment against leishmaniasis. The evidence about its use in New and Old World cutaneous leishmaniasis is presented and discussed.

RECENT FINDINGS

Miltefosine is being tested with small clinical trials mainly in endemic cutaneous leishmaniasis regions of South America and Iran. Severe cutaneous leishmaniasis forms successfully treated with miltefosine are reported.

SUMMARY

The use of miltefosine in cutaneous leishmaniasis has been addressed in a few clinical trials. An important advantage of this drug is its oral administration when compared with the standard parenteral drugs in the context of a large-scale use in the inner regions of the endemic countries. Miltefosine also shows activity in severe or refractory cases. However, this review points out the need for further investment on clinical research into cutaneous leishmaniasis treatment.

In vitro and in vivo efficacy of ether lipid edelfosine against Leishmania spp. and SbV-resistant parasites

Background

The leishmaniases are a complex of neglected tropical diseases caused by more than 20 Leishmania parasite species, for which available therapeutic arsenal is scarce and unsatisfactory. Pentavalent antimonials (SbV) are currently the first-line pharmacologic therapy for leishmaniasis worldwide, but resistance to these compounds is increasingly reported. Alkyl-lysophospoholipid analogs (ALPs) constitute a family of compounds with antileishmanial activity, and one of its members, miltefosine, has been approved as the first oral treatment for visceral and cutaneous leishmaniasis. However, its clinical use can be challenged by less impressive efficiency in patients infected with some Leishmania species, including L. braziliensis and L. mexicana, and by proneness to develop drug resistance in vitro.

Methodology/Principal Findings

We found that ALPs ranked edelfosine>perifosine>miltefosine>erucylphosphocholine for their antileishmanial activity and capacity to promote apoptosis-like parasitic cell death in promastigote and amastigote forms of distinct Leishmania spp., as assessed by proliferation and flow cytometry assays. Effective antileishmanial ALP concentrations were dependent on both the parasite species and their development stage. Edelfosine accumulated in and killed intracellular Leishmania parasites within macrophages. In vivo antileishmanial activity was demonstrated following oral treatment with edelfosine of mice and hamsters infected with L. major, L. panamensis or L. braziliensis, without any significant side-effect. Edelfosine also killed SbV-resistant Leishmania parasites in in vitro and in vivo assays, and required longer incubation times than miltefosine to generate drug resistance.

Conclusions/Significance

Our data reveal that edelfosine is the most potent ALP in killing different Leishmania spp., and it is less prone to lead to drug resistance development than miltefosine. Edelfosine is effective in killing Leishmania in culture and within macrophages, as well as in animal models infected with different Leishmania spp. and SbV-resistant parasites. Our results indicate that edelfosine is a promising orally administered antileishmanial drug for clinical evaluation.

Leishmaniasis represents a major international health problem, has a high morbidity and mortality rate, and is classified as an emerging and uncontrolled disease by the World Health Organization. The migration of population from endemic to nonendemic areas, and tourist activities in endemic regions are spreading the disease to new areas. Unfortunately, treatment of leishmaniasis is far from satisfactory, with only a few drugs available that show significant side-effects. Here, we show in vitro and in vivo evidence for the antileishmanial activity of the ether phospholipid edelfosine, being effective against a wide number of Leishmania spp. causing cutaneous, mucocutaneous and visceral leishmaniasis. Our experimental mouse and hamster models demonstrated not only a significant antileishmanial activity of edelfosine oral administration against different wild-type Leishmania spp., but also against parasites resistant to pentavalent antimonials, which constitute the first line of treatment worldwide. In addition, edelfosine exerted a higher antileishmanial activity and a lower proneness to generate drug resistance than miltefosine, the first drug against leishmaniasis that can be administered orally. These data, together with our previous findings, showing an anti-inflammatory action and a very low toxicity profile, suggest that edelfosine is a promising orally administered drug for leishmaniasis, thus warranting clinical evaluation.

Molecular Docking and in Vitro Antileishmanial Evaluation of Chromene-2-thione Analogues

Leishmaniases are an epidemic in various countries, and the parasite is developing resistance against available drugs. Thus, development of new drugs against Leishmania is an open area of investigation for synthetic organic chemists. To meet this challenge, a series of chromene-2-thione derivatives have been synthesized and docked into the active site of trypanothione reductase (TryR) enzyme required for redox balance of the parasite. These were screened on promastigote, axenic amastigote, and intracellular amastigote stages of Leishmania donovani and found to show high levels of antileishmanial activity together with minimal toxicity to human peripheral blood mononuclear cells. Compounds 3b and 3k were found to be the most active among the tested compounds. Although the compounds show moderate antileishmanial activity, they identify a chemical space to design and develop drugs based on these chromene-2-thione derivatives against the Leishmania parasite.

Leishmania donovani mitochondrial iron superoxide dismutase A is released into the cytosol during miltefosine induced programmed cell death

The oxidative phosphorylation process is the main source of endogenous reactive oxygen species (ROS) such as superoxide in mitochondria. In mammals, manganese superoxide dismutase plays an important role in detoxification of superoxide before it interferes with mitochondrial function and causes programmed cell death. Here, we investigated the role of Leishmania donovani mitochondrial iron superoxide dismutase-A (LdFeSODA) in protecting the parasite from oxidative stress and in the control of programmed cell death events. We have shown that overexpression of LdFeSODA protects Leishmania donovani from miltefosine induced cytotoxicity and reduced mitochondrial-derived superoxide generation. Furthermore, parasites overexpressing LdFeSODA showed (i) lower level of phosphatidylserine exposure as measured by flow cytometry and fluorescent microscopy; and (ii) reduced level of TUNEL staining of parasites compared to the control parasites. Finally, prolonged incubation of the parasites with miltefosine induced the release of both cytochrome C and LdFeSODA into the cytosol as demonstrated by Western blotting and fluorescence microscopy indicating programmed cell death. The results indicate that LdFeSODA protects the mitochondria of Leishmania from oxidative stress thereby inhibiting programmed cell death.

Genetic polymorphisms and drug susceptibility in four isolates of Leishmania tropica obtained from Canadian soldiers returning from Afghanistan

BACKGROUND

Cutaneous leishmaniasis (CL) is a vector-borne parasitic disease characterized by the presence of one or more lesions on the skin that usually heal spontaneously after a few months. Most cases of CL worldwide occur in Southwest Asia, Africa and South America, and a number of cases have been reported among troops deployed to Afghanistan. No vaccines are available against this disease, and its treatment relies on chemotherapy. The aim of this study was to characterize parasites isolated from Canadian soldiers at the molecular level and to determine their susceptibility profile against a panel of antileishmanials to identify appropriate therapies.

METHODOLOGY/PRINCIPAL FINDINGS

Parasites were isolated from skin lesions and characterized as Leishmania tropica based on their pulsed field gel electrophoresis profiles and pteridine reductase 1 (PTR1) sequences. Unusually high allelic polymorphisms were observed at several genetic loci for the L. tropica isolates that were characterized. The drug susceptibility profile of intracellular amastigote parasites was determined using an established macrophage assay. All isolates were sensitive to miltefosine, amphotericin B, sodium stibogluconate (Pentostam) and paromomycin, but were not susceptible to fluconazole. Variable levels of susceptibility were observed for the antimalarial agent atovaquone/proguanil (Malarone). Three Canadian soldiers from this study were successfully treated with miltefosine.

CONCLUSIONS/SIGNIFICANCE

This study shows high heterogeneity between the two L. tropica allelic versions of a gene but despite this, L. tropica isolated from Afghanistan are susceptible to several of the antileishmanial drugs available.

Noninferiority of miltefosine versus meglumine antimoniate for cutaneous leishmaniasis in children

BACKGROUND

Children have a lower response rate to antimonial drugs and higher elimination rate of antimony (Sb) than adults. Oral miltefosine has not been evaluated for pediatric cutaneous leishmaniasis.

METHODS

A randomized, noninferiority clinical trial with masked evaluation was conducted at 3 locations in Colombia where Leishmania panamensis and Leishmania guyanensis predominated. One hundred sixteen children aged 2-12 years with parasitologically confirmed cutaneous leishmaniasis were randomized to directly observed treatment with meglumine antimoniate (20 mg Sb/kg/d for 20 days; intramuscular) (n = 58) or miltefosine (1.8-2.5 mg/kg/d for 28 days; by mouth) (n = 58). Primary outcome was treatment failure at or before week 26 after initiation of treatment. Miltefosine was noninferior if the proportion of treatment failures was ≤15% higher than achieved with meglumine antimoniate (1-sided test, α = .05).

RESULTS

Ninety-five percent of children (111/116) completed follow-up evaluation. By intention-to-treat analysis, failure rate was 17.2% (98% confidence interval [CI], 5.7%-28.7%) for miltefosine and 31% (98% CI, 16.9%-45.2%) for meglumine antimoniate. The difference between treatment groups was 13.8%, (98% CI, -4.5% to 32%) (P = .04). Adverse events were mild for both treatments.

CONCLUSIONS

Miltefosine is noninferior to meglumine antimoniate for treatment of pediatric cutaneous leishmaniasis caused by Leishmania (Viannia) species. Advantages of oral administration and low toxicity favor use of miltefosine in children.

CLINICAL TRIAL REGISTRATION

NCT00487253.

Leishmaniasis chemotherapy--challenges and opportunities

Although there have been significant advances in the treatment of visceral leishmaniasis (VL), there remain challenges to ensure that treatments effective in India are also effective in other regions of the world and to identify treatment for post kala-azar dermal leishmaniasis as well as the opportunity to develop a safe oral short-course treatment. At the same time, there have been few advances for the treatment of simple or complex forms of cutaneous leishmaniasis (CL), other than topical paromomycin formulations. The main challenge for CL is to ensure that this disease is on the research and development agenda, so that new drugs are evaluated or compounds are screened in appropriate models, and that the standardization of quality of clinical trials is guaranteed. Problems also remain in the treatment of HIV/leishmaniasis co-infected patients. We are some way from having the ideal treatments for VL and CL and drug research and development for these diseases must remain focused.

Management of trypanosomiasis and leishmaniasis

BACKGROUND

The current treatments for human African trypanosomiasis (HAT), Chagas disease and leishmaniasis (collectively referred to as the kinetoplastid diseases) are far from ideal but, for some, there has been significant recent progress. For HAT the only advances in treatment over the past two decades have been the introduction of an eflornithine/nifurtimox co-administration and a shorter regime of the old standard melarsoprol.

SOURCES OF DATA

PubMed.

AREAS OF AGREEMENT

There is a need for new safe, oral drugs for cost-effective treatment of patients and use in control programmes for all the trypanosomatid diseases.

AREAS OF CONTROVERSY

Cutaneous leishmaniasis is not on the agenda and treatments are lagging behind.

GROWING POINTS

There are three compounds in development for the treatment of the CNS stage of HAT: fexinidazole, currently due to entry into phase II clinical studies, a benzoxaborole (SCYX-7158) in phase I trials and a diamidine derivative (CPD-0802), in advanced pre-clinical development. For Chagas disease, two anti-fungal triazoles are now in clinical trial. In addition, clinical studies with benznidazole, a drug previously recommended only for acute stage treatment, are close to completion to determine the effectiveness in the treatment of early chronic and indeterminate Chagas disease. For visceral leishmaniasis new formulations, therapeutic switching, in particular AmBisome, and the potential for combinations of established drugs have significantly improved the opportunities for the treatment in the Indian subcontinent, but not in East Africa.

AREAS TIMELY FOR DEVELOPING RESEARCH

Improved diagnostic tools are needed to support treatment, for test of cure in clinical trials and for monitoring/surveillance of populations in control programmes.

Phase 4 pharmacovigilance trial of paromomycin injection for the treatment of visceral leishmaniasis in India

Background. A phase 3 study demonstrated the safety and efficacy of paromomycin (paromomycin IM injection) for treatment of VL in an inpatient setting. Methods. This phase 4 study was conducted to assess the safety and efficacy of paromomycin in children and adults in an outpatient setting in Bihar, India. Results. This study enrolled 506 adult and pediatric patients. Of the 494 patients in the intent-to-treat (ITT) population, 98% received a full course of treatment. The overall study completion rate was 94% (462/494) for the ITT population and 96% (461/479) for the efficacy-evaluable (EE) population. Initial clinical cure was 99.6%, and final clinical cure 6 months after treatment was 94.2%. Grade 3 or 4 adverse events occurred in 5% of patients; events with a frequency of ≥1% were increases in alanine aminotransferase and aspartate aminotransferase. Conclusions. This study confirms the safety and efficacy of paromomycin to treat VL in an outpatient setting.

Use of oral miltefosine for cutaneous leishmaniasis in Canadian soldiers returning from Afghanistan

Old world cutaneous leishmaniasis (CL) is caused by Leishmania major and Leishmania tropica, and is endemic to several Asian and Middle-Eastern countries where the rates of infection can be substantial. CL is one of the most common vector-transmitted parasitic infections in Afghanistan. Six cases of CL in Canadian soldiers returning from Afghanistan are reported in the present study. Their lesions did not improve with fluconazole therapy, and the organism demonstrated in vitro resistance. Oral miltefosine seemed effective.

Phase IV trial of miltefosine in adults and children for treatment of visceral leishmaniasis (kala-azar) in Bangladesh

Miltefosine (target dose of 2.5 mg/kg/day for 28 days) is the recommended treatment for visceral leishmaniasis (kala-azar) in Bangladesh on the basis of data from India. We evaluated miltefosine in a phase IV trial of 977 patients in Bangladesh. At the six-month final follow up, 701 were cured. 24 showed initial treatment failure, and 95 showed treatment failure at 6 months, although 73 of the 95 showed treatment failure solely by the criterion of low hemoglobin values. One hundred twenty-one patients were not assessable. With the conservative assumption that all low hemoglobin values represented treatment failure, the final per protocol cure rate was 85%. Of 13 severe adverse events, 6 led to treatment discontinuation and 7 resulted in deaths, but only 1 death (associated with diarrhea) could be attributed to drug. Nearly all non-serious adverse events were gastrointestinal: vomiting in 25% of patients and diarrhea in 8% of patients. Oral miltefosine is an attractive alternative to intramuscular antimony and intravenous amphotericin B for treatment of kala-azar in Bangladesh.

Sitamaquine as a putative antileishmanial drug candidate: from the mechanism of action to the risk of drug resistance

Sitamaquine is a 8-aminoquinoline in development for the treatment of visceral leishmaniasis by oral route, no activity being observed on the experimental cutaneous leishmaniasis experimental models. Recent data explain how sitamaquine accumulate in Leishmania parasites, however its molecular targets remain to be identified. An advantage of sitamaquine is its short elimination half-life, preventing a rapid resistance emergence. The antileishmanial action of its metabolites is not known. The selection of a sitamaquine-resistant clone of L. donovani in laboratory and the phase II clinical trials pointing out some adverse effects such as methemoglobinemia and nephrotoxicity are considered for a further development decision.

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.

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.

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

BACKGROUND

Treatment options for visceral leishmaniasis (VL) in East Africa are far from satisfactory due to cost, toxicity, prolonged treatment duration or emergence of parasite resistance. Hence there is a need to explore alternative treatment protocols such as miltefosine alone or in combinations including miltefosine, sodium stibogluconate (SSG) or liposomal amphotericin B. The aim of this trial is to identify regimen(s) which are sufficiently promising for future trials in East Africa.

METHODS/DESIGN

A phase II randomized, parallel arm, open-labelled trial is being conducted to assess the efficacy of each of the three regimens: liposomal amphotericin B with SSG, Liposomal amphotericin B with miltefosine and miltefosine alone. The primary endpoint is cure at day 28 with secondary endpoint at day 210 (6 months). Initial cure is a single composite measure based on parasitologic evaluation (bone marrow, spleen or lymph node aspirate) and clinical assessment. Repeated interim analyses have been planned after recruitment of 15 patients in each arm with a maximum sample size of 63 for each. These will follow group-sequential methods (the triangular test) to identify when a regimen is inadequate (<75% efficacy) or adequate (>90% efficacy). We describe a method to ensure consistency of the sequential analysis of day 28 cure with the non-sequential analysis of day 210 cure.

DISCUSSION

A regimen with adequate efficacy would be a candidate for treatment of VL with reasonable costs. The design allows repeated testing throughout the trial recruitment period while maintaining good statistical properties (Type I & II error rates) and reducing the expected sample sizes.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01067443.

Antiparasitic therapy

Parasitic diseases affect more than 2 billion people globally and cause substantial morbidity and mortality, particularly among the world's poorest people. This overview focuses on the treatment of the major protozoan and helminth infections in humans. Recent developments in antiparasitic therapy include the expansion of artemisinin-based therapies for malaria, new drugs for soil-transmitted helminths and intestinal protozoa, expansion of the indications for antiparasitic drug treatment in patients with Chagas disease, and the use of combination therapy for leishmaniasis and human African trypanosomiasis.

Physicochemical and biological aspects of macrophage-mediated drug targeting in anti-microbial therapy

Macrophages are important drug targets as they mediate a wide variety of infectious diseases. Visceral leishmaniasis (VL), schistosomiasis, brucellosis, and salmonellosis are some of the well-known infectious diseases in which macrophages play a prominent pathophysiological role. For instance, VL parasites exclusively house in the macrophages of liver and spleen. They are resistant to lysosomal degradation by unknown mechanisms, they survive and thrive safely within macrophages, they multiply, and they ultimately affect visceral organs, leading to severe pathological and sometimes even fatal conditions. The majority of routinely used drugs administered in free form distribute all over the body via systemic circulation, leading to relatively low therapeutic activity and a certain degree of toxicity. Unlike for nonmicrobial diseases, targeting parasites procuring resistance and ineffective therapeutic outcome can be obviously speculated in case of infectious disease. The preferential uptake by macrophages, intended to improve the balance between efficacy and toxicity, can be achieved by the use of nanomedicines, i.e. submicron-sized macromolecular or particulate drug delivery systems. This insight has stimulated researchers to use nanomedicines--which tend to be recognized by macrophages as 'foreign' and consequently are taken up by the intended target cells much more effectively than their free drug counterparts--to improve the treatment of infectious diseases. The literature reports extensively on such approaches; however, there are several constraints that limit the application of nanomedicine in macrophage-mediated drug targeting. Here, we briefly describe the strategies that are used to achieve effective drug targeting to macrophages, using VL as a model disease, and we also put forth an understanding of the most important limiting factors. Various physicochemical and biological factors used by researchers as reported in the literature are addressed, and the most important mechanisms and modes by which macrophage-specific drug targeting can be achieved are summarized. Based on the evidence obtained to date, it can be concluded that targeting macrophages is a valuable and validated strategy for improving the treatment of infectious diseases.

Erufosine, an alkylphosphocholine, with differential toxicity to human cancer cells and bone marrow cells

PURPOSE

To investigate the activity and myeloprotective properties of erufosine, a novel alkylphosphocholine (APC), on human malignant cells and normal bone marrow cells.

METHODS

Human or mouse bone marrow cells were exposed to erufosine, miltefosine, perifosine, or edelfosine in CFU-GM assays. Human MDA-MB-231 breast carcinoma, Panc-1 pancreatic carcinoma, and RPMI8226 multiple myeloma cells were exposed to erufosine in colony formation assays. Colony formation of Panc-1 tumor cells and mouse bone marrow cells ex vivo were quantified following intravenous administration of erufosine to tumor-bearing mice. Western blotting methods were applied to human U87 glioblastoma cells exposed to erufosine to investigate Akt inhibition.

RESULTS

Erufosine was less toxic to human and mouse bone marrow cells than perifosine, miltefosine, and edelfosine and was equally toxic to human and mouse CFU-GM. The human cancer cells MDA-MB-231 breast, Panc-1 pancreatic, and RPMI8226 MM cells were more sensitive to erufosine in a colony formation assay than were human bone marrow cells generating an approximately tenfold differential in IC(90) values. Erufosine injected intravenously significantly reduced Panc-1 tumor cell colony formation ex vivo but not mouse bone marrow CFU-GM. Erufosine inhibited Akt phosphorylation in human U87 glioblastoma cells.

CONCLUSIONS

Erufosine offers potential as a novel therapeutic for cancer with a reduced toxicity profile to bone marrow cells compared with other agents in this class. Human cancer cells were more sensitive to erufosine than human or mouse bone marrow cells indicating a favorable therapeutic window for erufosine.

Anti-leishmanial activity of plant-derived acridones, flavaglines, and sulfur-containing amides

Visceral and cutaneous leishmaniases are an important public health problem in endemic geographic regions in 88 countries worldwide, with around 12 million infected people. Treatment options are limited due to toxicity and teratogenicity of the available drugs, response problems in HIV/Leishmania co-infections, and upcoming resistances. In this study, we investigated the anti-leishmanial activity of 13 plant-derived compounds in vitro aiming to find new drug candidates. Toxicity of the compounds was evaluated in human primary hepatocytes, and hemolytic activity was examined in freshly isolated erythrocytes. Two acridones, 5-hydroxynoracronycine and yukocitrine, two flavaglines, aglafoline and rocaglamide, and the sulfur-containing amide methyldambullin showed promising anti-leishmanial activities with 50% effective concentrations (EC50s) of 34.84, 29.76, 7.45, 16.45, and 6.29 μM, respectively. Hepatotoxic activities of 5-hydroxynoracronycine, yukocitrine, and methyldambullin were significantly lower compared to miltefosine and lower or equal compared to artesunate, whereas the ones of rocaglamide and aglafoline were slightly higher compared to miltefosine and significantly higher compared to artesunate. None of the compounds showed hemolytic activity.

A chemotype that inhibits three unrelated pathogenic targets: the botulinum neurotoxin serotype A light chain, P. falciparum malaria, and the Ebola filovirus

A 1,7-bis(alkylamino)diazachrysene-based small molecule was previously identified as an inhibitor of the botulinum neurotoxin serotype A light chain metalloprotease. Subsequently, a variety of derivatives of this chemotype were synthesized to develop structure-activity relationships, and all are inhibitors of the BoNT/A LC. Three-dimensional analyses indicated that half of the originally discovered 1,7-DAAC structure superimposed well with 4-amino-7-chloroquinoline-based antimalarial agents. This observation led to the discovery that several of the 1,7-DAAC derivatives are potent in vitro inhibitors of Plasmodium falciparum and, in general, are more efficacious against CQ-resistant strains than against CQ-susceptible strains. In addition, by inhibiting β-hematin formation, the most efficacious 1,7-DAAC-based antimalarials employ a mechanism of action analogous to that of 4,7-ACQ-based antimalarials and are well tolerated by normal cells. One candidate was also effective when administered orally in a rodent-based malaria model. Finally, the 1,7-DAAC-based derivatives were examined for Ebola filovirus inhibition in an assay employing Vero76 cells, and three provided promising antiviral activities and acceptably low toxicities.

[Alkylphosphocholines inhibit lens epithelial cell proliferation and attachment]

BACKGROUND

Posterior capsule opacification (PCO) is one of the major concerns in modern cataract surgery. Ten years after successful surgery, Nd:YAG capsulotomy is required in up to 42% of patients with an acrylic sharp-edged intraocular lens (IOL). Some accommodative and multifocal IOLs display even higher capsulotomy rates. Pharmacologic prophylaxis with alkylphosphocholines (APCs) could be a novel option in PCO prevention.

METHODS

The human lens epithelial cell line HLE-B3 served as an in-vitro model. After incubation with APCs in different concentrations (0.01, 0.1, and 1 mM), the trypan blue exclusion assay and the live/dead test were performed at serum concentrations of only 5%. Cell proliferation was assessed with the MTT test. Evaluation of cell attachment was done with fibronectin- and laminin-coated wells.

RESULTS

APCs can inhibit the proliferation of human lens epithelial cells in the presence of only 5% serum in a dose-dependent manner. Proliferation inhibition of 60% and attachment inhibition of about 50% were reached at concentrations of 0.1 µM.

CONCLUSION

APCs inhibit proliferation and attachment of human lens epithelial cells in nontoxic concentrations in vitro. The substance can be applied topically, and an intraoperative application for pharmacologic PCO prophylaxis is feasible.

Urine antigen detection by latex agglutination test for diagnosis and assessment of initial cure of visceral leishmaniasis

This prospective study evaluated the usefulness of the kala-azar latex agglutination test (KAtex) for the diagnosis and laboratory assessment of initial cure of visceral leishmaniasis (VL) (or kala-azar) patients following 30 days of sodium antimony gluconate treatment at Rajshahi Medical College Hospital (Bangladesh). KAtex detects a low molecular weight, heat-stable, carbohydrate antigen in the urine of VL patients. KAtex was performed using freshly voided urine samples obtained from 36 parasitologically confirmed cases of VL before and after treatment as well as from 40 healthy controls (20 each from kala-azar-endemic and non-endemic zones). KAtex was found to be positive in 27 (75%) of the 36 patients at diagnosis and was negative in all the controls. The diagnostic sensitivity and specificity of KAtex were 75% (95% CI 57-87%) and 100% (95% CI 89-100%), respectively. Following treatment, all 36 VL cases were negative for Leishman-Donovan bodies by splenic smear microscopy and 34 (94.4%) were negative by KAtex. This limited study suggests that KAtex is a satisfactorily sensitive, highly specific, rapid and completely non-invasive urine-based antigen detection test for the diagnosis of VL. Currently, this is the only non-invasive laboratory tool useful for the assessment of initial cure in VL patients.

A species-specific approach to the use of non-antimony treatments for cutaneous leishmaniasis

We used a species-specific approach to treat 10 patients with cutaneous leishmaniasis diagnosed using polymerase chain reaction. Non-antimony treatments (oral miltefosine, ketoconazole, and liposomal amphotericin B) were chosen as an alternative to pentavalent antimony drugs based on likely or proven drug efficacy against the infecting species. Leishmania Viannia panamensis was diagnosed in three patients and treated successfully with oral ketoconazole. Miltefosine treatment cured two patients with L. infantum chagasi. A wide variety of Leishmania responded to liposomal amphotericin B administered for 5-7 days. Three patients with L. V. braziliensis, one patient with L. tropica, and two patients with L. infantum chagasi were treated successfully. One person with L. V. braziliensis healed slowly because of a resistant bacterial superinfection, and a second patient with L. infantum chagasi relapsed and was retreated with miltefosine. These drugs were reasonably well-tolerated. In this limited case series, alternative non-antimony-based regimens were convenient, safe, and effective.

Comparison of short-course multidrug treatment with standard therapy for visceral leishmaniasis in India: an open-label, non-inferiority, randomised controlled trial

BACKGROUND

Improved treatment approaches are needed for visceral leishmaniasis. We assessed the efficacy and safety of three potential short-course combination treatments compared with the standard monotherapy in India.

METHODS

Standard treatment (1 mg/kg amphotericin B infusion on alternate days for 30 days, total dose 15 mg/kg) was compared with three drug combinations (single injection of 5 mg/kg liposomal amphotericin B and 7-day 50 mg oral miltefosine or single 10-day 11 mg/kg intramuscular paromomycin; or 10 days each of miltefosine and paromomycin) in an open-label, parallel-group, non-inferiority, randomised controlled trial in two hospital sites in Bihar, India. Patients aged 5-60 years with parasitologically confirmed visceral leishmaniasis were randomly assigned one of the four treatments by the trial statistician by use of a computer-generated list. Clinical assessments were done at the end of treatment (15 days on combination treatment; 31 days for standard treatment) and after 45 days and 6 months. The primary endpoint was definitive cure (defined as no sign or symptom of visceral leishmaniasis and parasitologically cured to the last follow-up). Analyses were done both by intention to treat and per protocol. This trial is registered with ClinicalTrials.gov, number NCT00696969.

FINDINGS

Between June, 2008, and July, 2009, 634 patients were assigned amphotericin B (n=157), liposomal amphotericin B with miltefosine (n=160) or paromomycin (n=158), or miltefosine and paromomycin (n=159). 618 patients were in the per-protocol population. There were two relapses in each group. The numbers with definitive cure at 6 months for the intention-to-treat population were 146 (cure rate 93·0%; CI 87·5-96·3) for amphotericin B, 156 (97·5%; 93·3-99·2) for liposomal amphotericin B and miltefosine, 154 (97·5%; 93·24-99·2) for liposomal amphotericin B and paromomycin, and 157 (98·7%; 95·1-99·8) for miltefosine and paromomycin. All combinations were non-inferior to the standard treatment, in both the intention-to-treat and per-protocol populations. Patients in the combination groups had fewer adverse events than did those assigned standard treatment.

INTERPRETATION

Combination treatments for visceral leishmaniasis are efficacious and safe, and decrease the duration of therapy, thereby encouraging adherence and reducing emergence of drug-resistant parasites.

FUNDING

Drugs for Neglected Diseases initiative and the Indian Council of Medical Research.

Immunotherapy as a strategy for treatment of leishmaniasis: a review of the literature

Leishmaniasis occurs as a spectrum of clinical syndromes divided into cutaneous, mucocutaneous and visceral forms. The epidemiology and clinical features are highly variable owing to the interplay of many factors ranging from parasite species and strains, vectors, host genetics and environment. Currently, there is no effective licensed vaccine for use in humans against leishmaniasis. Most traditional and low-cost treatment options, particularly in poor and endemic areas, are toxic with many adverse reactions and they require a long course of administration. The use of more effective, less toxic drugs is limited because total treatment cost is very high (expensive) and there are fears of development of drug resistance. Recent studies indicate that certain strategies aimed at modulating the host immune response (collectively called immunotherapy) could result in prophylactic and/or therapeutic cure of leishmaniasis under both laboratory and field conditions. In this review, we focus on treatment of leishmaniasis with a particular emphasis on immunotherapy/immunochemotherapy as an alternative to conventional drug treatment.

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

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

Miltefosine in the treatment of cutaneous leishmaniasis caused by Leishmania braziliensis in Brazil: a randomized and controlled trial

Background

Cutaneous leishmaniasis (CL) is treated with parenteral drugs for decades with decreasing rate cures. Miltefosine is an oral medication with anti-leishmania activity and may increase the cure rates and improve compliance.

Methodology/Principal Findings

This study is a randomized, open-label, controlled clinical trial aimed to evaluate the efficacy and safety of miltefosine versus pentavalent antimony (Sb^v) in the treatment of patients with CL caused by Leishmania braziliensis in Bahia, Brazil. A total of 90 patients were enrolled in the trial; 60 were assigned to receive miltefosine and 30 to receive Sb^v. Six months after treatment, in the intention-to-treat analyses, the definitive cure rate was 53.3% in the Sb^v group and 75% in the miltefosine group (difference of 21.7%, 95% CI 0.08% to 42.7%, p = 0.04). Miltefosine was more effective than Sb^v in the age group of 13–65 years-old compared to 2–12 years-old group (78.9% versus 45% p = 0.02; 68.2% versus 70% p = 1.0, respectively). The incidence of adverse events was similar in the Sb^v and miltefosine groups (76.7% vs. 78.3%). Vomiting (41.7%), nausea (40%), and abdominal pain (23.3%) were significantly more frequent in the miltefosine group while arthralgias (20.7%), mialgias (20.7%) and fever (23.3%) were significantly more frequent in the Sb^v group.

Conclusions

This study demonstrates that miltefosine therapy is more effective than standard Sb^v and safe for the treatment of CL caused by Leishmania braziliensis in Bahia, Brazil.

Trial Registration

Clinicaltrials.gov Identifier NCT00600548

Cutaneous leishmaniasis (CL) is characterized by skin ulcerations and occurs in rural poor areas of developing countries. It is treated with daily injections of antimony for 20 days, which is associated with irregular use and increasingly lower cure rates. Miltefosine is an oral medication with activity against the agent of CL (Leishmania). We have studied the efficacy and safety of miltefosine compared with antimony in patients with CL caused by Leishmania braziliensis in Bahia, Brazil. A total of 90 patients participated; 60 received miltefosine and 30 were treated with antimony. Six months after treatment, 75% of patients treated with miltefosine were cured, compared with 53% of the patients in the antimony group, a difference considered significant (p = 0.04). We also found that miltefosine was more effective than antimony in adults than in children. The incidence of side effects was similar with both drugs (76.7% vs. 78.3%), but all patients were able to finish the treatments. Our study shows that miltefosine is more effective than antimony for the treatment of CL in Bahia, Brazil and can contribute to the control of this disease due to its activity and easier administration.

Risk factors for relapse of visceral leishmaniasis in Georgia

The number of relapses in patients treated for visceral leishmaniasis (VL) has increased, thus identifying prognostic factors may aid decisions on treatment. Demographic and clinical information was abstracted from medical records of patients diagnosed and treated in Georgia from 2002 to 2004. The 300 persons with VL were primarily children <5 years (73.3%), and ∼44% had delays in diagnosis of more than 30 days from symptom onset. All patients received standard therapy with pentavalent antimony (20 mg/kg/day), most for 20-25 days. Factors significantly associated with VL relapse were delay in diagnosis for >90 days (RR = 4.21, 95% CI: 1.58, 11.16), haemoglobin level <60 g/l (RR = 11.96, 95% CI: 4.12, 34.76) and age <1 year (RR = 2.36, 95% CI: 0.96, 5.80). Physician and public education is needed to reduce delays in diagnosis. Prolonging treatment for 30 days (e.g. WHO recommendation) or implementing new regimens may reduce the number of relapses.

Ambisome plus miltefosine for Indian patients with kala-azar

The combination of one intravenous administration of 5mg/kg Ambisome and oral administration of miltefosine, 2.5mg/kg/day for 14 days, was evaluated in 135 Indian patients with kala-azar. The Intent-to-Treat cure rate at 6 months was 124 of the 135 enrolled patients (91.9%: 95% CI = 86-96%), and the per protocol cure rate was 124 of 127 evaluable patients (97.6%: 95% CI = 93-100%). Side effects could be attributed to each drug separately: fevers, rigors and back pain due to Ambisome; gastrointestinal side effects due to miltefosine. This combination is attractive for reasons of efficacy, tolerance, and feasibility of administration, although the gastrointestinal side effects of miltefosine require medical vigilance. Clinical Trials.gov identification number: NCT00371995.

Current diagnosis and treatment of visceral leishmaniasis

Human visceral leishmaniasis (VL), a potentially fatal disease, is most prevalent in the Indian subcontinent, East Africa and South America. Definite diagnosis and effective treatment are the primary needs for the control of VL. Diagnosis of VL has typically relied on microscopic examination of bone marrow/splenic aspirate, but serology and molecular methods are now better alternatives. The conventional drugs for treatment of VL have limitations including unresponsiveness, relapse, specific toxicities and parenteral administration lasting for long durations. Moreover, they are less effective in HIV-VL-coinfected patients. Registration of miltefosine and paromomycin, and preferential pricing of AmBisome has offered more choices for monotherapy and combination therapy for VL. Combination therapy will increase treatment efficacy and prevent the development of resistance. In addition, active case finding and vector control strategies will also have a positive impact in the control of VL. This article critically addresses the currently available diagnostic and treatment regimens for the control of VL.

"Smart" liposomal nanocontainers in biology and medicine

The perspectives of using liposomes for delivery of drugs to desired parts of the human body have been intensively investigated for more than 30 years. During this time many inventions have been suggested and different kinds of liposomal devices developed, and a number of them have reached the stages of preclinical or clinical trials. The latest techniques can be used to develop biocompatible nano-sized liposomal containers having some abilities of artificial intellect, such as the presence of sensory and responsive units. However, only a few have been clinically approved. Further improvements in this area depend on our knowledge of the interactions of drugs with the lipid bilayer of liposomes. Further studies on liposomal transport through the human body, their targeting of cells requiring therapeutic treatment, and finally, the development of techniques for controlled drug delivery to desired acceptors on cell surfaces or in cytoplasm are still required.