When anti-HIV drugs fail to suppress the condition or prevent transmission, the situation is usually blamed on a patient who does not take the treatment as is needed for it to work correctly. Recent research, however, shows that some individuals, and even some parts of the body may be genetically predisposed to treatment failure.

Consider the drug Tenofovir. It is on the market under the brand name Viread, and the FDA approved this medication back in 2001 as an HIV treatment. Then in 2012 approval was given for use as an oral prophylactic, this time with the goal of preventing HIV transmission.

Unfortunately, some people, and also some parts of the body, have enzymes that take the active Tenofovir and return it to an inactive state that does not combat HIV. The research showed different enzymes to be at work in the vagina and rectum causing the treatment to have different results depending on where it was used on the body. But even when used in the same manner, results still varied.

That is because the location of the treatment was not the only determining factor. About one in 12 women who were part of the study suffered from a genetic variation that rendered the medication inert regardless of how it was used.

Learning this is a big step for researchers since it was previously just assumed that human error was involved when the drug didn’t work. Now the realization is that genetics may be involved. The next stage of research may reveal that genetic testing can determine in advance if Tenofovir is a viable treatment option or not for a particular individual.

The next step is a clinical trial. It is hoped that such continued research will determine how anti-HIV drugs function and what variants definitely affect how successful the treatment will be from person to person.