A completed series of investigations into the iPrEx study of tenofovir/FTC(Truvada) at pre-exposure prophylaxis (PrEP) has found that the drug was 87% efficacious in preventing HIV infection amongst those who had detectable drug levels, though only 42% efficacious overall.
An expanded number of drug-level tests show that only 44% of those who did not become infected with HIV had drug detectable in their blood and/or cells, suggesting that overall adherence in the study was even lower than thought. This suggests that adherence will be the factor that may limit the effectiveness of this strategy in curbing HIV in many populations, and that it may need to be offered only to people highly motivated to take it.
The iPrEx study reported its initial findings in November 2010. It found at this point that the overall efficacy of the drug in preventing HIV was 44%, in other words that nine HIV infections our of 20 that would otherwise have happened were prevented.
Complete article at AIDS Map : http://bit.ly/qPdKBT