Oral miltefosine for Indian visceral leishmaniasis

Antimony uptake systems in the protozoan parasite Leishmania and accumulation differences in antimony-resistant parasites

The first line drug against leishmaniasis consists of pentavalent antimony [Sb(V)], but there is general belief that the active form of the metal is the trivalent form [Sb(III)]. In this study, we have quantified the accumulation of Sb(V) and Sb(III) in Leishmania by using inductively coupled plasma mass spectrometry. The accumulation was studied in three Leishmania species at various life stages, sensitive or resistant to antimony. Both Sb(III) and Sb(V) are accumulated in promastigote and amastigote parasites, but through competition experiments with arsenite, we found that the routes of entry of Sb(V) and Sb(III) are likely to differ in Leishmania. The level of accumulation of either Sb(III) or Sb(V), however, was not correlated with the susceptibility of wild-type Leishmania cells to antimony. This suggests that other factors may also be implicated in the mode of action of the drugs. In contrast to metal susceptibility, resistance to Sb(III) correlated well with decreased antimony accumulation. This phenotype was energy dependent and highlights the importance of transport systems in drug resistance of this protozoan parasite.

Visceral leishmaniasis in immunocompromised patients with and without AIDS: a comparison of clinical features and prognosis

Visceral leishmaniasis is basically a disease of healthy infants and adults. However, in the last decade an increasing number of cases of kala azar in immunocompromised patients have been reported with emphasis on atypical manifestations of the disease. During a period of 11 years, 20 immunocompromised patients with AIDS (12 patient), haematological neoplasia (3 patients), corticosteroid therapy (3 patients) or renal transplantation (2 patients) were studied by one or more of the authors. We did not find differences in the presentation of leishmaniasis between patient with or without AIDS and most patients had fever, enlargement of the liver and spleen, blood cytopenias and biochemical abnormalities. Serology was more frequently positive in HIV-negative than in HIV-positive patients (100% versus 63.6%; P=0.13). Bone marrow biopsy was diagnostic in 66% and 87% of patients with and without AIDS, respectively. Failure of anti-leishmanial therapy occurred in 6 of 19 patients treated (31.5%), and 3 patients with AIDS and another 3 without AIDS died during the first episode of leishmaniasis. Of 12 survivors, relapses occurred in five (41.6%). Only patients in whom immunosuppression was ameliorated by means of antiretroviral therapy or by reduction of corticosteroid and other immunosuppressive drugs did not relapse. Treatment of kala azar in immunocompromised host is in satisfactory and new drugs or strategies are urgently needed.

Prevention of opportunistic infections in adult and adolescent patients with HIV infection. GESIDA/National AIDS Plan guidelines, 2004 [correction]

OBJECTIVE

To provide an update of guidelines from the Spanish AIDS Study Group (GESIDA) and the National AIDS Plan (PNS) committee on the prevention of opportunistic infections in adult and adolescent HIV-infected patients.

METHODS

These consensus recommendations have been produced by a group of experts from GESIDA and/or the PNS after reviewing the earlier document and the scientific advances in this field in the last years. The system used by the Infectious Diseases Society of America and the United States Public Health Service has been used to classify the strength and quality of the data.

RESULTS

This document provides a detailed review of the measures for the prevention of infections caused by viruses, bacteria, fungi and parasites in the context of HIV infection. Recommendations are given for preventing exposure and for primary and secondary prophylaxis for each group of pathogens. In addition, criteria are established for the withdrawal of prophylaxis in patients who respond well to highly active antiretroviral therapy (HAART).

CONCLUSIONS

HAART is the best strategy for the prevention of opportunistic infections in HIV-positive patients. Nevertheless, prophylaxis is still necessary in countries with limited economic resources, in highly immunodepressed patients until HAART achieves beneficial effects, in patients who refuse to take or who cannot take HAART, in those in whom HAART is not effective, and in the small group of infected patients with inadequate recovery of CD4+ T lymphocyte counts despite good inhibition of HIV replication.

Oral delivery of meglumine antimoniate-beta-cyclodextrin complex for treatment of leishmaniasis

The need for daily parenteral administration represents one of the most serious limitations in the clinical use of pentavalent antimonials against leishmaniasis. In this work, we investigated the ability of beta-cyclodextrin to enhance the oral absorption of antimony and to promote the oral efficacy of meglumine antimoniate against experimental cutaneous leishmaniasis. The occurrence of interactions between beta-cyclodextrin and meglumine antimoniate was demonstrated through the changes induced in the spin lattice relaxation times of protons in both compounds. When free and complexed meglumine antimoniate were given orally to Swiss mice, plasma antimony levels were found to be about three times higher for the meglumine antimoniate-beta-cyclodextrin complex than for the free drug. Antileishmanial efficacy was evaluated in BALB/c mice experimentally infected with Leishmania amazonensis. Animals treated daily with the complex (32 mg of Sb/kg of body weight) by the oral route developed significantly smaller lesions than those treated with meglumine antimoniate (120 mg of Sb/kg) and control animals (treated with saline). The effectiveness of the complex given orally was equivalent to that of meglumine antimoniate given intraperitoneally at a twofold-higher antimony dose. The antileishmanial efficacy of the complex was confirmed by the significantly lower parasite load in the lesions of treated animals than in saline-treated controls. This work reports for the first time the effectiveness of an oral formulation for pentavalent antimonials.

In vitro and in vivo activities of a triterpenoid saponin extract (PX-6518) from the plant Maesa balansae against visceral leishmania species

The in vitro and in vivo activities of a mixture of six oleane triterpene saponins, recovered from the methanolic extract of the leaves of the Vietnamese plant Maesa balansae (PX-6518), were evaluated against drug-sensitive visceral Leishmania strains. The in vitro 50% inhibitory concentration (IC(50)) against intracellular Leishmania infantum amastigotes was 0.04 micro g/ml. The cytotoxic concentrations causing 50% cell death (CC(50)s) were about 1 micro g/ml in murine macrophage host cells and >32 micro g/ml in human fibroblasts (MRC-5 cell line). Evaluation in the Leishmania donovani BALB/c mouse model indicated that a single subcutaneous administration of 0.4 mg/kg at 1 day after infection reduced liver amastigote burdens by about 95% in all treated animals. If treatment was delayed until 14 days after infection, a dose of 1.6 mg/kg of body weight was required to maintain the same level of activity. Single 250-mg/kg doses of sodium stibogluconate (Pentostam) 1 and 14 days after infection produced comparable efficacies. A single dose of PX-6518 at 2.5 mg/kg administered 5 days before infection was still 100% effective in preventing liver infection, suggesting a particularly long residual action. Spleen and bone marrow could not be cleared by PX-6518 nor sodium stibogluconate. PX-6518 did not show activity after oral dosing at up to 200 mg/kg for 5 days. This study concludes that triterpenoid saponins from M. balansae show promising in vitro and in vivo antileishmanial potential and can be considered as new lead structures in the search for novel antileishmanial drugs.

Miltefosine: an oral drug for visceral leishmaniasis

Miltefosine, a phosphocholine analogue originally developed as antimalignant drug, has been found to be highly active against leishmania in vitro and animal model. Based on these experiences this drug was tried against human visceral leishmaniasis and found to be highly effective and achieved 97% and 94% cure in phase 2 and phase 3 trial in children.

Amphotericin B Treatment for Indian Visceral Leishmaniasis: Conventional versus Lipid Formulations

In Bihar, India, where visceral leishmaniasis is hyperendemic, amphotericin B deoxycholate is now first-line parenteral treatment. To test the efficacy of amphotericin B deoxycholate versus that of its lipid formulations, Indian patients were randomized to receive treatment with amphotericin B deoxycholate (1 mg/kg on alternate days for 30 days; n=51), liposomal amphotericin B (2 mg/kg per day for 5 days; n=51), or amphotericin B lipid complex (2 mg/kg per day for 5 days; n=51). Infusion-associated reactions were frequent and persistent in subjects treated with amphotericin B deoxycholate. The illness of 3 patients failed to respond to treatment, and 5 patients experienced relapse. Final cure rates were similar. Estimated total treatment costs for a 25-kg patient-417 dollars for amphotericin B deoxycholate, 872 dollars for liposomal amphotericin B, and 947 dollars for amphotericin B lipid complex-differed as a result of drug cost. Substantial reductions (approximately 60%) in the price of liposomal amphotericin B and amphotericin B lipid complex would make treatment costs comparable to that of amphotericin B deoxycholate, permitting administration of short-course regimens in India.

Transcriptional Activation of p21waf1/cip1 by Alkylphospholipids

Alkylphospholipids (ALKs) are a novel class of antitumor agents with an unknown mechanism of action. The first ALK tested in the clinic, miltefosine, has been approved recently in Europe for the local treatment of patients with cutaneous metastasis. Perifosine, the only available oral ALK, is being studied currently in human cancer clinical trials. We have shown previously that perifosine induces p21(waf1/cip1) in a p53-independent fashion and that induction of p21(waf1/cip1) is required for the perifosine-induced cell cycle arrest because cell lines lacking p21(waf1/cip1) are refractory to perifosine. In this report, we investigated the mechanism by which perifosine induces p21(waf1/cip1) protein expression. We observed that perifosine induces the accumulation of p21(waf1/cip1) mRNA without affecting p21(waf1/cip1) mRNA stability. Using several p21(waf1/cip1) promoter-driven luciferase reporter plasmids, we observed that perifosine activates the 2.4-kb full-length p21(waf1/cip1) promoter as well as a p21 promoter construct lacking p53-binding sites, suggesting that perifosine activates the p21(waf1/cip1) promoter independent of p53. The minimal p21 promoter region required for perifosine-induced p21 promoter activation contains four consensus Sp1-binding sites. Mutations in each particular Sp1 site block perifosine-induced p21(waf1/cip1) expression. Moreover, we showed that perifosine activates the mitogen-activated protein/extracellular signal-regulated kinase pathway, and this activation promotes the phosphorylation of Sp1 in known mitogen-activated protein kinase residues (threonine 453 and 739), thereby leading to increased Sp1 binding and enhanced p21(waf1/cip1) transcription. These results represent a novel mechanism by which alkylphospholipids modulate transcription, and may contribute to the discovery of new signal transduction pathways crucial for normal and neoplastic cell cycle control.

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.

Mucocutaneous leishmaniasis in a US citizen

Mucocutaneous leishmaniasis (MCL) is endemic to many areas of Central and South America. A case of MCL in a US citizen is reported here. An ulcer appeared on the patient's left hard palate, years after a working trip to Peru. Punch biopsies of the lesion were obtained, Leishmania promastigotes were isolated by culture and animal inoculation, and the patient was appropriately treated. As this case demonstrates, a patient's travel history is a key element in making a differential diagnosis of oral lesions.

Current treatment approaches to leishmaniasis

PURPOSE OF REVIEW

The leishmaniases consist of cutaneous, mucosal, and visceral syndromes. The classic treatment is with pentavalent antimonials. The disadvantages of the antimonials are their requirement for intramuscular or intravenous injection each day for 20-28 days, their toxicity, and the recent development of resistance in regions such as India. Amphotericin B is a potent secondary agent, but is also compromised by its parenteral nature and toxicity. Clinical investigation of treatment agents from January 2000 to January 2003 is reviewed to determine if there are new agents that can be used.

RECENT FINDINGS

A large number of pilot studies on visceral and cutaneous leishmaniasis have been performed. There can be more confidence in the visceral studies because visceral disease is incurable if untreated, and because large numbers of patients have been treated in highly endemic regions such as India. There is less confidence in pilot studies of the cutaneous disease, because most are uncontrolled, and there is a variable, and often high, cure rate without treatment.

SUMMARY

Liposomal amphotericin B, which is injected infrequently and is easily tolerated, is virtually 100% effective for Indian visceral disease at a total dose of 15 mg/kg and is 90% effective at a dose of 5-10 mg/kg. The oral agent, miltefosine, is more than 95% effective for Indian visceral disease. Fluconazole treatment for 6 weeks speeds up the already-rapid cure rate of cutaneous disease due to Leishmania major.

Miltefosine (Impavido): the first oral treatment against leishmaniasis

Miltefosine is a novel antileishmanial drug that has significant selectivity in both in vitro and in vivo models. Clinical efficacy was demonstrated for the treatment of visceral leishmaniasis with the advantage of oral administration over the currently recommended antileishmanial drugs that require parenteral administration. Miltefosine produces high cure rates also in patients resistant to the standard antimonial therapy.

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

Widespread antimony resistance renders conventional amphotericin B the only option for the treatment of visceral leishmaniasis (VL) in North Bihar, India. Because of its excellent safety profile, a large dose (7.5 mg/kg) of liposomal amphotericin B (L-AmB) was given to each of 203 patients with VL at 4 treatment centers, and the patients were discharged the next day. At initial clinical and parasitological follow-up, performed on day 30 after treatment, evidence of a cure was seen in 195 (96%) of 203 patients (95% CI, 92-98); 4 patients experienced treatment failure. Two patients were lost to follow-up, 2 died (one due to progressive disease and another, 5 months after treatment, due to an unrelated illness), and 12 experienced relapses during follow-up. Thus, 183 patients (90%; 95% CI, 85-94) had obtained final cure 6 months after treatment. Very few adverse events (fever with rigor, in 9.8% of patients) were seen. Single-dose L-AmB (7.5 mg/kg) treatment is safe and effective, and it may be used for the mass treatment of VL in India.

Visceral leishmaniasis in lung transplantation

Infection by intracellular microorganisms with a special geographic distribution, such as Leishmania spp, has been reported in a limited number of patients undergoing solid-organ transplant (SOT). No cases of Leishmania spp infection in lung transplant patients were found in a review of the literature. In our series of 222 lung or heart and lung transplantations performed from February 1990 to October 2002, two cases of visceral leishmaniasis (VL) were diagnosed and treated with liposomal amphotericin B. All cases reported to date in transplant patients, including the ones discussed here, occurred in people living in or traveling to countries in the Mediterranean area. We therefore consider it advisable to include serological testing for latent infection due to Leishmania spp in pretransplantation screening for our geographical setting, despite the limited return of this strategy.

Neglected diseases: under-funded research and inadequate health interventions. Can we change this reality?

Can we change this reality?

Product R&D for neglected diseases. Twenty-seven years of WHO/TDR experiences with public-private partnerships

Twenty-seven years of WHO/TDR experience with public–private partnerships

Oral miltefosine treatment in children with mild to moderate Indian visceral leishmaniasis

BACKGROUND

Miltefosine is the first oral drug with demonstrable success in treating visceral leishmaniasis in adults. Because approximately one-half of the visceral leishmaniasis patients worldwide are children, we performed a Phase I/II dose ranging study in the pediatric population in India.

METHODS

Thirty-nine (39) children (defined as < 12 years of age) with visceral leishmaniasis demonstrated by parasites in splenic aspirates, were treated with oral miltefosine daily for 28 days: 21 patients received 1.5 mg/kg/day (Group A); and 18 patients received 2.5 mg/kg/day (Group B). About one-half of these children had failed prior antileishmanial treatment.

RESULTS

All patients were parasitologically negative and symptomatically improved by the end of therapy on Day 28 of therapy; the initial parasitologic cure rate was 100%. Two patients in each treatment group relapsed with fever, splenomegaly and parasite-positive splenic aspirates by the end of the 6-month follow-up. The per protocol final clinical cure rate was 19 of 21 = 90% in Group A and 15 of 17 = 88% in Group B. Miltefosine was well-tolerated. As per the adult experience, gastrointestinal adverse events were seen: 33 and 39% of children experienced vomiting and 5 and 17% experienced diarrhea in Groups A and B, respectively, but all episodes were mild to moderate in severity and commonly lasted <1 day without symptomatic treatment.

CONCLUSION

Oral miltefosine was safe and approximately 90% effective in this initial clinical trial of childhood visceral leishmaniasis.

[Therapy of tropical diseases after returning from travel]

Most tropical diseases imported by travelers can be treated quite effectively. Human endoparasites belong to the protozoa and worms. Protozoa can be seen as microparasites, characterized by short generation periods and high rates of reproduction within a host--consequently the diseases mainly are of short duration. Effective drugs are available for malaria, amebiasis and other intestinal protozoa as well as for leishmaniasis. Resistance, however, sometimes is a problem. Worms are macroparasites that generally do not reproduce within a host--teleologically speaking because otherwise they would rapidly damage their own basis of living. Accordingly, severe worm disease is rarely found in travelers. Levels of anthelminthic resistances so far are low. The most important worm disease in travelers is schistosomiasis, a disease that also can be treated effectively if diagnosed early.

Localized mucosal leishmaniasis due to Leishmania (Leishmania) infantum: clinical and microbiologic findings in 31 patients

The clinical and microbiologic characteristics of 31 patients with mucosal leishmaniasis due to Leishmania (Leishmania) infantum are described. Twenty-eight (90%) patients were male. Mean age at presentation was 48 +/- 14 years. Thirteen (42%) patients had no underlying disease, while 18 (58%) patients had several other medical conditions. Fifteen (48%) patients were immunocompromised, 7 patients were infected with human immunodeficiency virus (HIV), and 3 were graft recipients. The primary location of lesions was the larynx in 11 (35%) patients, oral mucosa in 10 (32%) patients, and the nose in 5 (16%) patients. Mucosal lesions were painless in all patients but 2 and consisted of whitish, red, or violaceous nodular swelling or tumorlike masses. Ulceration was reported in 6 patients. Pathologically, the lesions showed a chronic inflammatory infiltrate. Granuloma may be seen. The localization of the lesions determined the symptomatology of the disease. Symptoms included hoarseness, difficulty swallowing, and nasal obstruction. The disease presentation was usually protracted, with a mean time from the onset of symptoms to diagnosis of 13 months (range, 3 wk-4.5 yr), and the clinical diagnosis was usually mistaken for neoplasia of the upper aerodigestive tract. No laboratory abnormalities were found in these patients due to the localized disease, apart from those attributed to underlying diseases. Parasites were easily identified in smears or sections by Giemsa stain or hematoxylin-eosin stain. Leishmania was grown in culture in 12 (60%) patients; culture was negative in 8 (40%) patients. Leishmania (Leishmania) infantum was identified in only 9 instances. The following zymodemes were reported: MON-1 (2 patients), MON-24 (2 patients), MON-27 (1 patient), and MON-34 (1 patient). Serologic test results were known in 25 patients. Serology was usually positive at low titer; 6 (24%) patients had negative serologic test results. Twenty patients were treated with antimonial compounds for between 3 and 36 days. Three patients were given drugs other than antimonial drugs. Five patients were treated only locally, by surgery (3 patients) or topical medical therapy. One patient received no therapy, and treatment was not reported in 2 cases. Patients were cured in 25 (89%) cases, and sequelae were uncommon (14%). Relapse was detected in 2 individuals and 1 patient developed visceral leishmaniasis after treatment. Two HIV-coinfected patients died of causes unrelated to leishmaniasis. The results of the present report stress the clinical importance of searching for the presence of Leishmania in patients with suspected neoplasia of the upper respiratory tract if they have visited or resided in zones endemic for Leishmania (Leishmania) infantum. The treatment of choice for these patients is not established yet, but most patients respond to antimonial compounds given for 28 days or less.