AFRICA: River blindness drug trial launched
Man infected with onchocerciasis
DAKAR, 1 July 2009 (IRIN) - Researchers are launching a clinical trial with 1,500 people infected with onchocerciasis (river blindness) in Liberia, Ghana and the Democratic Republic of Congo to test a remedy that could help stop transmission, according to drug manufacturer Wyeth Pharmaceuticals and the World Health Organization (WHO).
Onchocerciasis – transmitted through black flies that breed near rivers – is one of the leading causes of blindness in Africa, according to WHO.
The primary prevention method is black fly control, while treatment has been through annual doses of ivermectin, which relieves intense itchiness of the skin and eye lesions. “The drug is harmless, like aspirin, and is given annually to people who are at risk,” said Boakye Boatin of the joint WHO, UN and World Bank tropical disease research programme.
Nelson Weah from Liberia’s capital Monvoria told IRIN ivermectin treatments helped him to see again. “I once suffered from river blindness and could not see at all. I felt like I was living in a dark world. I could not do anything for myself and relied on others.”
But while ivermectin might successfully treat individuals, it does not stop the infection from spreading, said Boatin. “It reduces rather than stops transmission because it does not kill adult worms, only the eggs.”
Adult worms live in a person’s skin and lay eggs that are then picked up and carried by black flies. If adult worms are not killed they continue to lay eggs in the skin and the disease can be passed on.
The drug moxidectin is being studied for its potential to kill adult worms carrying the disease and to wipe out the disease in any high-risk area within six years, Boatin told IRIN.
More than 100 million people, mostly in Africa, are at risk of infection, according to WHO.
More than 10 years in development, the trial drug moxidectin is manufactured by Wyeth Pharmaceuticals. The company’s vice-president, Henrietta Ukwu, told IRIN Wyeth has invested US$20 million over the last decade in the drug, including $6 million for the upcoming clinical trial expected to last two and a half years.
WHO estimates there are about half a million people, mostly in Africa, who are blind due to onchocerciasis.