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Cancer drug might be key weapon against leishmaniasis

17 Jun 2008

Joao Souza

Source: PLoS Neglected Tropical Diseases (see original article)

Diffuse cutaneous leishmaniasis (DCL)

An alternative drug might soon be added to the arsenal against Leishmania amazonensis, one of the species responsible for the incidence of cutaneous leishmaniasis in many South American countries.

A study, published June 2008 in the open-access journal PLoS Neglected Tropical Diseases, found that tamoxifen – a medication widely used in the treatment and prevention of breast cancer – fights the parasitic disease in experimentally infected mice.

The experiment was carried out by a team of Brazilian researchers from the Department of Parasitology of the Institute of Biomedical Sciences at the University of São Paulo. The team, led by Dr Silvia Uliana, observed a significant reduction in parasite burden – as well as a notable delay in the development of skin ulcers – in previously lab infected mice after a two-week administration of tamoxifen.

Leishmaniasis is an anthropozoonotic infectious disease caused by 20 species of unicellular parasites pathogenic for humans belonging to the genus Leishmania. L. amazonensis is responsible for causing the cutaneous and mucocutaneous forms of the disease, as well as the diffuse cutaneous leishmaniasis (DCL), with a wide range of clinical manifestations in humans – especially severe skin and mucosal ulcerations.

Chemotherapy has always been a critical issue in the management of leishmaniasis. To date, the classical choices for its treatment have been painful and prolonged parenteral applications of pentavalent antimonials, amphotericin B or pentamidine – all of them presenting high toxicity levels for the patients.

Tamoxifen has been used as an anti-oestrogen in the treatment and prevention of breast cancer since the 1970s. Therefore, its safety and pharmacological profiles are well established in humans.

Although promising, the current findings point out to the necessity of further experimental models of infection before the drug is tested in humans. ‘Nobody should start using tamoxifen as a treatment against leishmaniasis yet. Its effectiveness in humans for this specific matter remains still unpredictable’, said Dr Uliana.