HIV Microbicide Hope
posted: 10/02/2009
For the first time a study has shown that a microbicide gel can reduce the risk of male-to-female HIV transmission. Microbicide advocates are pleased, but the results of the larger PRO2000 microbicide study, due late this year, will be crucial in determining the next steps for microbicides.
Some reduction in HIV transmission to women
In this study, the PRO2000 microbicide was tested in a clinical trial involving over 3000 women.
Results showed that it reduced the risk of HIV transmission by 30%. This wasn’t quite a statistically significant result. HIV was found 2.7 times per 100 person years amongst women using PRO2000 compared with 4 per 100 person years for the women in other parts of the study.
But when the researchers repeated their analysis and took into account the time women weren’t using the gel, their results showed that use of PRO2000 resulted in a statistically significant 36% reduction in the risk of HIV transmission.
Other analysis showed that the more often women used the gel, the higher the level of protection it provided.
Used without condoms
The researchers also tried to see how effective PRO2000 was at preventing HIV infections in women who didn’t use condoms. They found new HIV infections in 1% of women who used only the microbicide for HIV prevention. It was 4% amongst women who were given the placebo gel. They therefore concluded that, amongst women who didn’t use condoms, over 75% of HIV infections appeared to be prevented by PRO2000.
How would PRO2000 be used? One of the study's researchers suggested that it, "may be a niche product for women with no other choices".
It is unlikely that any microbicide will achieve the protection level of condoms, but since many women have little or no control over whether condoms are used, some protection, even if it is imperfect, is better than no protection. That is the main niche for microbicides.
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