Therapeutic options for cutaneous leishmaniasis

The pipeline for drugs for control and elimination of neglected tropical diseases: 2. Oral anti-infective drugs and drug combinations for off-label use

In its 'Road map for neglected tropical diseases 2021-2030', the World Health Organization outlined its targets for control and elimination of neglected tropical diseases (NTDs) and research needed to achieve them. For many NTDs, this includes research for new treatment options for case management and/or preventive chemotherapy. Our review of small-molecule anti-infective drugs recently approved by a stringent regulatory authority (SRA) or in at least Phase 2 clinical development for regulatory approval showed that this pipeline cannot deliver all new treatments needed. WHO guidelines and country policies show that drugs may be recommended for control and elimination for NTDs for which they are not SRA approved (i.e. for 'off-label' use) if efficacy and safety data for the relevant NTD are considered sufficient by WHO and country authorities. Here, we are providing an overview of clinical research in the past 10 years evaluating the anti-infective efficacy of oral small-molecule drugs for NTD(s) for which they are neither SRA approved, nor included in current WHO strategies nor, considering the research sponsors, likely to be registered with a SRA for that NTD, if found to be effective and safe. No such research has been done for yaws, guinea worm, Trypanosoma brucei gambiense human African trypanosomiasis (HAT), rabies, trachoma, visceral leishmaniasis, mycetoma, T. b. rhodesiense HAT, echinococcosis, taeniasis/cysticercosis or scabies. Oral drugs evaluated include sparfloxacin and acedapsone for leprosy; rifampicin, rifapentin and moxifloxacin for onchocerciasis; imatinib and levamisole for loiasis; itraconazole, fluconazole, ketoconazole, posaconazole, ravuconazole and disulfiram for Chagas disease, doxycycline and rifampicin for lymphatic filariasis; arterolane, piperaquine, artesunate, artemether, lumefantrine and mefloquine for schistosomiasis; ivermectin, tribendimidine, pyrantel, oxantel and nitazoxanide for soil-transmitted helminths including strongyloidiasis; chloroquine, ivermectin, balapiravir, ribavirin, celgosivir, UV-4B, ivermectin and doxycycline for dengue; streptomycin, amoxicillin, clavulanate for Buruli ulcer; fluconazole and isavuconazonium for mycoses; clarithromycin and dapsone for cutaneous leishmaniasis; and tribendimidine, albendazole, mebendazole and nitazoxanide for foodborne trematodiasis. Additional paths to identification of new treatment options are needed. One promising path is exploitation of the worldwide experience with 'off-label' treatment of diseases with insufficient treatment options as pursued by the 'CURE ID' initiative.

Accelerated healing of cutaneous leishmaniasis in non-healing BALB/c mice using water soluble amphotericin B-polymethacrylic acid

Cutaneous leishmaniasis (CL) is a neglected tropical disease that causes prominent skin scaring. No water soluble, non-toxic, short course and low cost treatment exists. We developed a new water soluble amphotericin B-polymethacrylic acid (AmB-PMA) using established and scalable chemistries. AmB-PMA was stable for 9 months during storage. In vitro, it was effective against Leishmania spp. promastigotes and amastigote infected macrophages. It was also less toxic and more effective than deoxycholate-AmB, and similar to liposomal AmB. Its in vivo activity was determined in both early and established CL lesion models of Leishmania major infection in genetically susceptible non-healing BALB/c mice. Intradermal AmB-PMA at a total dose of 18 mg of AmB/kg body weight led to rapid parasite killing and lesion healing. No toxicity was seen. No parasite relapse occurred after 80 days follow-up. Histological studies confirmed rapid parasite clearance from macrophages followed by accelerated fibroblast mediated tissue repair, regeneration and cure of the infection. Quantitative mRNA studies of the CL lesions showed that accelerated healing was associated with increased Tumour Necrosis Factor-α and Interferon-γ, and reduced Interleukin-10. These results suggest that a cost-effective AmB-PMA could be used to pharmacologically treat and immuno-therapeutically accelerate the healing of CL lesions.

Molecular factors governing inhibition of arylimidamides against Leishmania: conservative computational modeling to improve chemotherapies

A dataset of 55 compounds with inhibitory activity against Leishmania donovani axenic amastigotes and Leishmania amazonensis intracellular parasites was examined through three-dimensional quantitative structure-activity relationship modeling employing molecular descriptors from both rigid and flexible compound alignments. For training and testing purposes, the compounds were divided into two datasets of 45 and 10 compounds, respectively. Statistically significant models were constructed and validated via the internal and external predictions. For all models employing steric, electrostatic, hydrophobic, H-donor and H-acceptor molecular descriptors, the R² values were greater than 0.90 and the SEE values were less than 0.22. The models obtained from rigid and flexible compounds were employed together to obtain a conservative method for predictions. This method minimized under predictions. Molecular descriptors from the models were then extrapolated, for the overall predictive devices and the individual compounds, and examined with regard to inhibitory activity. Information gained from the molecular descriptors is useful in the design of novel compounds. The models obtained can be employed to predict activities of the compounds designed and/or form predictions for compounds that exist and have not yet been examined with biological inhibitory assays.

Tropical medicine rounds: Treatment of Old World cutaneous leishmaniasis with dapsone, itraconazole, cryotherapy, and imiquimod, alone and in combination

BACKGROUND

Cutaneous leishmaniasis (CL) is a major public health problem. The currently available therapies are expensive, not freely available, toxic, and not always curative. A simple, effective, noninvasive therapeutic approach is required for the treatment of CL.

AIMS

To determine the clinical patterns of CL and to report our experience in the management of CL.

METHODS

One hundred and ten patients with CL seen between January 2005 and December 2007 were included in this study. The diagnosis was based on clinical features, parasitologic diagnosis, histopathology, and culture. Each patient was treated according to disease severity with either topical (cryotherapy or imiquimod) or systemic (itraconazole or dapsone) monotherapy, or a combination of these modalities.

RESULTS

CL was more common in adult expatriate men, with the upper limbs as the most commonly affected site. Noduloulcerative CL was the most common presentation (84.6%). Atypical CL was found in 18 patients. Skin biopsy was the most common diagnostic technique (66.6%). Monotherapy showed an overall success rate of 56.41%, whereas combination therapy was successful in 69.56% of cases. Cryotherapy alone was successful in 68.18% of cases. Imiquimod alone was ineffective.

CONCLUSION

A stepwise approach represents a rational and practical way of confirming CL. A combination of itraconazole/dapsone and topically applied imiquimod is safe, simple, and effective for the treatment of CL. More studies are needed to establish the role of such an approach. Cryotherapy is also safe, simple and effective for the treatment of CL.

Intralesional sodium stibogluconate alone or its combination with either intramuscular sodium stibogluconate or oral ketoconazole in the treatment of localized cutaneous leishmaniasis: a comparative study

BACKGROUND

Cutaneous leishmaniasis (CL) is a disease caused by leishmania species. Intralesional sodium stibogluconate (SSG) has been considered the first line therapy for localized cutaneous leishmaniasis. There is still a need for more effective and less time-consuming therapeutic methods for this condition.

OBJECTIVE

The aim of the present study was to investigate if the combination of intramuscular (IM) SSG or oral ketoconazole with intralesional (IL) SSG would be more effective than the intralesional SSG given alone in the treatment of localized cutaneous leishmaniasis.

PATIENTS AND METHODS

Thirty patients with confirmed diagnosis of cutaneous leishmaniasis were included in the study. They were randomly assigned to three groups. The first group (10 patients with 12 lesions) was treated with intralesional SSG alone. The second group (10 patients with 15 lesions) was treated with the combination of intralesional SSG + intramuscular SSG. The third group (10 patients with 13 lesions) was treated with the combination of intralesional SSG and oral ketoconazole. A follow-up was performed every 4 weeks for a treatment period of 12 weeks, then monthly for a period of 6 months after the end of the treatment.

RESULTS

Complete cure occurred in 58.3% of lesions in group 1, while 93.3% and 92.3% of lesions were cured in group 2 and 3 respectively. The difference between group 1 and the other groups was statistically significant (P < 0.05).

CONCLUSION

Combined intramuscular SSG or oral ketoconazole with intralesional SSG is more effective than intralesional SSG alone for the treatment of CL. Oral ketoconazole is much easier and safer therapy than intramuscular SSG in combination with intralesional SSG in the treatment of localized cutaneous leishmaniasis.

Cutaneous leishmaniasis (Leishmania tropica) in a German tourist after travel to Greece

We report on a German tourist returning from vacations in Southern Greece with cutaneous leishmaniasis (CL) presenting as multiple erythematosquamous lesions caused by Leishmania tropica (zymodeme MON-57). In spite of its endemicity, only few data are available on the incidence and current distribution of CL in Greece, which may allow for an assessment of the risk for travelers.

The relationship between leishmaniasis and AIDS: the second 10 years

To date, most Leishmania and human immunodeficiency virus (HIV) coinfection cases reported to WHO come from Southern Europe. Up to the year 2001, nearly 2,000 cases of coinfection were identified, of which 90% were from Spain, Italy, France, and Portugal. However, these figures are misleading because they do not account for the large proportion of cases in many African and Asian countries that are missed due to a lack of diagnostic facilities and poor reporting systems. Most cases of coinfection in the Americas are reported in Brazil, where the incidence of leishmaniasis has spread in recent years due to overlap with major areas of HIV transmission. In some areas of Africa, the number of coinfection cases has increased dramatically due to social phenomena such as mass migration and wars. In northwest Ethiopia, up to 30% of all visceral leishmaniasis patients are also infected with HIV. In Asia, coinfections are increasingly being reported in India, which also has the highest global burden of leishmaniasis and a high rate of resistance to antimonial drugs. Based on the previous experience of 20 years of coinfection in Europe, this review focuses on the management of Leishmania-HIV-coinfected patients in low-income countries where leishmaniasis is endemic.