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WHO researchers start trial on a new drug for river blindness

BMJ 2009; 339 doi: https://doi.org/10.1136/bmj.b2755 (Published 09 July 2009) Cite this as: BMJ 2009;339:b2755
  1. Nayanah Siva
  1. 1London

    Researchers at the World Health Organization are to begin a clinical trial in three African countries for a new drug, moxidectin, in the hope of eliminating river blindness.

    River blindness, onchocerciasis, is one of the most devastating parasitic diseases, prevalent in many African countries, and is transmitted by the blackfly, which breeds in fast flowing rivers. Currently, the disease is controlled by the drug ivermectin, which has been donated to countries where onchocerciasis is endemic for the past 20 years by the pharmaceutical company Merck.

    “Ivermectin is a time tested, safe drug for the community in general,” says Hannan Masud, an ophthalmologist at the Combined Military Hospital in Nowshera, Pakistan, but adds that ivermectin is “contraindicated for pregnant and lactating women, and in children less than 8 years of age.” These two groups make up a significant section of the population, for whom there is no medicine, says Dr Masud.

    Ivermectin works by killing the larvae of the parasite, Onchocerca volvulus, which can alleviate symptoms and reduce transmission. However, the drug does not work on adult parasites.

    “Preclinical data in animal models suggest that moxidectin may either sterilise or kill the adult worms,” said Annette Kuesel, project manager for moxidectin at the WHO. “Ivermectin does not do that, even though repeated treatments reduce the reproductive capacity of the adult worms.”

    The research will be conducted by the Special Programme for Research and Training in Tropical Diseases, an independent global programme, sponsored by the United Nations Children’s Fund, the World Bank, and the WHO that works to combat major diseases in poor and disadvantaged communities.

    The programme will be enrolling 15 000 people for the study at four sites in Ghana, Liberia, and the Democratic Republic of Congo. The programme will involve African investigators and institutions.

    Ms Kuesel hopes that the new research will allow the collection of additional data on the effect of moxidectin compared with ivermectin, in terms of efficacy and safety. The aim is to have a treatment that can be administered once or twice a year to interrupt the transmission of the disease.

    At the moment ivermectin needs to be given once or twice a year for between 11 and 14 years to ensure control of the disease. Researchers believe moxidectin has the potential to control the disease after six cycles of treatment.

    Peter Hotez, president of the Sabin Vaccine Institute and editor in chief of PLoS Neglected Tropical Diseases, says the new research is essential, particularly as onchocerciasis is one of the seven most prevalent neglected tropical diseases. “To rely on only a single drug for purposes of this mass drug administration is a very high risk strategy,” he said. Currently, we only have ivermectin, says Dr Hotez, adding that “even if it is a terrific drug, it would be highly desirable to have a back-up agent or a second first line agent.”

    Notes

    Cite this as: BMJ 2009;339:b2755

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