Researchers Look to Pill, Taken Daily, to Avert HIV. 04/08/08
New York Times (08.04.08)::Lawrence K. Altman
Researchers are conducting and planning clinical trials worldwide to test the concept that a daily dose of antiretroviral drugs, called PrEP, for pre-exposure prophylaxis, can prevent HIV infection. The AIDS Vaccine Advocacy Coalition (AVAC) presented a report about the trials Sunday at the 17th International AIDS Conference in Mexico City.
According to AVAC, by mid-2009, up to 15,000 people will be enrolled in various sites including Botswana, Brazil, Ecuador, Kenya, Malawi, Peru, South Africa, Tanzania, Thailand, Uganda, and the United States. The trials are being undertaken in part because of the success in giving antiretroviral drugs to pregnant women to prevent HIV infection in their infants.
The US Agency for International Development, CDC, the National Institutes of Health, and the Bill and Melinda Gates Foundation are funding the trials.
"We cannot wait for the study results to begin to prepare for the optimal use and delivery of PrEP," said Pedro Goicochea, a PrEP study investigator in Peru and Ecuador. PrEP, if successful, would need to be combined with standard prevention measures, and governments would need to be supported with adequate health care staffing, among other measures.
In 2007, Family Health International completed a similar study of the antiretroviral drug tenofovir among young Ghanaian women, showing that such preventive use was both safe and acceptable among uninfected users. However, the study did not show if PrEP could prevent new infections. Nonhuman primate studies testing PrEP against the simian form of HIV are promising.
Initial PrEP studies are testing tenofovir, either alone or combined with another drug, emtricitabine. Trial participants include men who have sex with men, heterosexual men and women, serodiscordant couples, and sex workers.
AVAC also said that with so much trial data being pooled, the results may be hard to interpret. Questions needing further study may also be raised, such as whether taking pills intermittently, like just before a sexual act, can be effective. Access AVAC's report here.