Disappointing Results for a Promising Microbicide

In December 2009, hopes were dashed when results from a large study revealed that the microbicide PRO 2000 was ineffective at protecting women from getting HIV. Given the modest results highlighted earlier in the year from a smaller US study of the product, some believed that PRO 2000 might become the breakthrough microbicide.

The earlier US study followed nearly 3,100 women using the vaginal microbicide gel to prevent HIV. But in spite of its encouraging results (a 30% decrease in HIV infections), the "relatively" small size of the study needed more follow-up.

The more recent results come from a 4-year British study that followed 9,385 women in Africa. Half the women used PRO 2000 (resulting in 130 infections) while the other half used a placebo gel (resulting in 123 infections).

Another gel, with the HIV drug tenofovir, is also in study. Given the steady rate of new infections worldwide, there is a need to study as many prevention methods as possible, especially for women who face situations in which their partners refuse to wear condoms.