Microbicide hopes fade with poor trial results
[DURBAN] Women's 'last hope' for protecting themselves from HIV infection with a standard vaginal gel has died after the remaining candidate proved ineffective.
PRO 2000, a vaginal microbicide gel, had been hailed as the most promising microbicide in a decade of research on female-controlled prevention methods.
But the results of a clinical trial published this week (14 December) found no evidence that PRO 2000 reduces the risk of HIV infection — infection rates were similar in both groups.
The trial, in South Africa, Tanzania, Uganda and Zambia, involved more than 9,000 women between September 2005 and September 2009. It followed a smaller trial of the gel, which had indicated that using the gel might reduce HIV infections by a third (see Microbicide hope at last, say researchers).
Salim Karim, director of the Centre for the Aids Programme of Research in South Africa (CAPRISA), said the results were "deeply disappointing" and called for more research to find a means for women to protect themselves from HIV.
Gita Ramjee, director of South Africa's Medical Research Council HIV Prevention Unit and principal investigator of the earlier PRO 2000 trial, said that researchers were committed to finding an HIV prevention option for women.
She said that studies are now focusing on more potent products; specifically exploring the use of antiretrovirals in pill, and vaginal gel and ring form for prevention (see Antiretroviral microbicides enter clinical trials).
"The need for a woman-controlled HIV prevention technology is critically important to turn the tide of the epidemic, especially in southern Africa. One promising new approach is the new generation of antiretroviral-containing microbicides," agreed Karim.
CAPRISA is testing the antiretroviral gel tenofovir and the results are expected in July 2010, said Karim.
Ramjee said that there are several trials underway using antiretroviral drugs in prevention, including a pilot study comparing tenofovir with a placebo at the University of KwaZulu-Natal, and the VOICE (Vaginal and Oral Interventions to Control the Epidemic) study being run the Microbicide Trials Network in South Africa, Uganda, Zambia and Zimbabwe.
The VOICE study also involves testing rectal antiretrovirals for prevention of HIV transmission between men.
The PRO 2000 trial was carried out by the Microbicides Development Programme, a not-for-profit partnership of 16 African and European research institutions.