HIV Prevention is Complex When Using Antiviral Drug Combinations

Researchers at the Oak Crest Institute of Science have been exploring new ways to prevent the spread of HIV-1 among young women in low and middle-income countries.

Some questions have been answered in a new study, and the answers may be surprising.

In a recent study published by the journal Nature on March 21, 2023, using humanized mice (mice that have received implants of human cells and tissues so that they can be infected with HIV-1), researchers tested the vaginal HIV-1 prevention efficacy of single and combination antiviral compounds applied locally.

They used a mathematical model to empirically study the effects of administering different doses of antiviral drugs.

The results were unexpected: when tenofovir disoproxil fumarate (TDF) and emtricitabine (FTC) – both drugs that share the same mechanism of inhibiting HIV-1 reverse transcriptase, thereby preventing viral replication in immune cells – were combined with a third drug that used a different mode of action against HIV-1, a strong antagonistic effect was observed.

This means that the drugs were less effective when used together than they were when used separately.

'Our approach provides a translational template for the preclinical, rational, and systematic evaluation of drug combinations for the prevention of HIV-1 and other viral diseases,' wrote these researchers.

As of April 7, 2023, there are no approved HIV vaccines available.