Final Results Of Largest Ever HIV Microbicide Trial Revealed

Results from the largest international clinical trial to date into a preventative HIV gel are published in the Lancet. The trial found that, although safe, there was no evidence that the vaginal microbicide PRO 2000 reduces the risk of HIV infection in women. The trial was part-funded and sponsored by the Medical Research Council (MRC).

A crucial finding from the study published today shows that women enrolled on the trial were willing to use the gel as part of their regular sexual routine, with 89 per cent of women reporting that they had used the gel the last time they had sex. By showing that the women and their partners found the gel acceptable, this trial paves the way for a future effective microbicide, which would offer women the first ever autonomous method of HIV protection.

The placebo-controlled trial MDP 301 involved over 9,000 women at six research centres in four African countries. It found that the risk of HIV infection in women who were supplied with PRO 2000 gel was much the same in women supplied with placebo gel. For the benefit for the women who took part in the trial, the headline results outlining the safety and ineffectiveness of the gel were announced in December 2009.

Dr Sheena McCormack from the MRC Clinical Trials Unit and MDP 301 chief investigator says:

“Of course we are disappointed that the gel was shown not to be effective, especially after the promising signal seen in a preceding trial conducted by the NIH funded HIV Prevention Trials Network. However MDP301 is still an important scientific result and it shows clearly the need to undertake independent trials to provide robust evidence for whether or not a product works. It would not have been possible to carry out such a complex trial without the crucial partnerships between African and European researchers, and above all the participation and commitment of the women in the trial.”

Results from a subsequent microbicide trial, CAPRISA 004, were published in July of this year showing that, when used before and after sex, an anti-retroviral gel called tenofovir reduces the risk of HIV infection by 39 per cent and herpes infection by 51 per cent. The trial was led by the Center for the AIDS Program of Research in South Africa (CAPRISA) at the University of KwaZulu-Natal and involved nearly 900 women. This groundbreaking trial provides proof that a microbicide can reduce the risk of HIV infection in women.

Dr McCormack continues:

“‘The desperation of the HIV epidemic and the urgent need to find a method of protection that can be administered by both men and women hasn’t gone away. Researchers now need to build on the positive CAPRISA 004 results for tenofovir by conducting independent trials in broader populations ideally looking at simpler regimens to pave the way for programmatic roll-out.”

The MDP 301 trial took place between September 2005 and September 2009 and was carried out by the Microbicides Development Programme (MDP), a not-for-profit partnership of 16 African and European research institutions. It was funded by the UK Department for International Development (DFID) and the Medical Research Council (MRC).

The partnership involved both African and European researchers and enhanced the collective capacity to deliver large scale complex trials in resource-poor settings, working in collaboration with community authorities and members.

PRO2000 vaginal gel for prevention of HIV-1 infection (Microbicides Development Programme 301) a phase 3, randomised, double-blind, parallel-group trial is published in the Lancet today, 20 September 2010.

Source: Medical Research Council

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