The World Health Organization reports that a clinical trial is being launched in three African countries of a drug that could eliminate onchocerciasis, or river blindness, one of the leading infectious causes of blindness across Africa. The drug, moxidectin, is being investigated for its potential to kill or sterilize the adult worms of Onchocerca volvulus, which cause onchocerciasis.
Currently, the disease is controlled by ivermectin, which has been donated for more than 20 years by the pharmaceutical company Merck & Co. for use in onchocerciasis endemic countries. Treatment with ivermectin has enabled significant progress in the control of onchocerciasis, and currently reaches more than 60 million people in Africa annually. However, ivermectin kills the O. volvulus larvae but not the adult worms, so annual treatments for an extended period of time (at least 11-14 years) are required to ensure disease control.
If moxidectin kills not only the larvae but also sterilizes or kills the adult worms, it has the potential to interrupt the disease transmission cycle within around 6 annual rounds of treatment. The drug could be distributed through the community-directed mechanisms set up in collaboration among APOC, African control programmes, and NGOs for the distribution of ivermectin.
“This is a devastating illness that has plagued 30 African countries for centuries, in particular the populations in the most remote areas ‘beyond the end of the road’,” says Dr Uche Amazigo, Director of the African Programme for Onchocerciasis Control (APOC). “Over 100 million people are at risk of infection with onchocerciasis in Africa and a few small areas in the Americas and Yemen.”
The development of moxidectin for onchocerciasis is being conducted through a collaboration of the Special Programme for Research and Training in Tropical Diseases (TDR), which is administered by WHO, with Wyeth Pharmaceuticals. The work ranges from the development of a formulation for human use and initial studies in healthy volunteers, to clinical studies and community studies in Africa.
TDR is building the capacity and managing the clinical trials in Africa. If the development is successful and results in a positive scientific opinion from the European Medicines Evaluation Agency, Wyeth with the assistance of WHO will request approval by regulatory authorities in the countries where onchocerciasis is endemic.
The trial will take place over the next two and a half years.
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PAHO’s vaccine system hampers African efforts
Efforts to make newer and more costly vaccines widely available to the poorest in Africa are being hampered by a long-standing system that makes vaccines affordable to middle-income Latin American countries, reports the Financial Times.
The Pan American Health Organization’s (PAHO) revolving fund, which began in 1979, negotiates substantial discounts with manufacturers on prices in richer countries, offering in exchange significant volumes, predictable demand and funding.
At issue is a clause demanding that the vaccines purchased for these middle-income countries are made available at the “lowest possible price” charged anywhere in the world, making it impossible to negotiate even lower prices to poorer countries.
Disagreement between PAHO and the Global Alliance on Vaccines and Immunisations (GAVI), has already delayed wider use of certain vaccines amongst the poorest of countries.
GAVI uses mechanisms such as advance market commitments and IFFIm’s (long-term, guaranteed aid funding from donor countries) to overcome historic limitations to development funding for immunisation.
GAVI also relies on the principle of tiered pricing to provide vaccines to the poorest of countries. Countries are grouped using a range of indicators of ability to pay, with poorer countries paying less per vaccine.
Companies have been increasingly willing to offer discounts on western prices to poorer countries, but they want richer countries to pay more in line with income levels to help support access to the poorest as well as research for future products.
Tension emerged last year over Wyeth’s vaccine against pneumonia and meningitis, which was offered to the revolving fund at $26 a dose, less than a third of its price in richer countries. However, the fund’s demand for the lowest possible price clashes with negotiations at $7 a dose for countries served by Gavi – with gross national income less than $1,000 a head.
Filed under: Africa, Central and South America, Commentary on news & events, Public health | Tagged: access to medicines, drug pricing, GAVI Alliance, Pan-American Health Organization | Leave a Comment »