The only HIV prevention drug approved for use by the US Federal Drug Administration does not provide the same level of protection for women as men, if both sexes are provided with the same dose. The results of a new study into Truvada suggest that women may require up to three-times the weekly dosage of the drug as a male recipient, in order to benefit from the same level of protection.
Whereas men can gain maximum protection by taking just two doses per week, researchers at North Carolina University found that women need a dose of Truvada every day to match the same level of protection.
The results were published this week in the Journal of Infectious Diseases.
Approved by the FDA for widespread use in 2012, Truvada is routinely used by those at the highest risk of HIV infection. The drug has been credited with bringing the number of new cases of HIV down significantly each year since its introduction, though it is only now that evidence suggests different doses may be required for men and women.
For the purposes of the study, 47 healthy women were given measured doses of Truvada, from whom samples of rectal, cervical and vaginal tissues were taken. They were looking for exactly how much of the drug made it to the female-specific tissues, discovering that much less Truvada was present in cervical and vaginal tissue than rectal tissue.
When the data was analyzed, it suggested that while men may not need more than two doses of Truvada per week, women may need a daily dose to benefit from the same level of protection.
The research team stated that the findings should prompt doctors and scientist alike to look more closely at varying Truvada dosage, in order to ensure that each individual recipient benefits from maximum protection.
“Our data highlight the fact that one dose does not fit all,” wrote University of North Carolina researchers, Angela Kashuba.
“In determining how best to use drugs to protect people from HIV, we need to understand where in their body they are at risk for being infected, along with the concentration of drug that is needed to protect that site from infection.”
The research team insisted that while the findings were significant, it would be inadvisable for Truvada uses to in any way alter their intake of the drug until being advised to do so by their doctors.
“We are excited to be able to apply our research methods to explain the conundrum of mixed clinical trial results of Truvada prevention, and how men and women should best use HIV prevention therapy,” Kashuba added.
“Yet we would like to remind people who are taking pre-exposure prophylaxis that Truvada should be taken every day to reduce the risk of acquiring HIV infection. Patients should not change their medication regimen without first consulting their physicians.”