A double-blind Irish PrEP study run by UCD and The Mater Hospital will examine the effectiveness of Truvada when compared with a new combination drug

UCD and The Mater Hospital are carrying out a study on the effectiveness of PrEP in preventing HIV from being acquired and they are looking for gay men and trans women to participate in it.

In this double-blind study, the effectiveness of two drugs is being evaluated.

The study will compare the effectiveness of Truvada (F/TDF), which contains the drugs emtricitabine (F) and tenofovir disoproxil fumarate (TDF), with a new drug containing emtricitabine (F) and tenofovir alafenamide (TAF), F/TAF.

Both drugs are currently used in the treatment of HIV, whereas only Truvada has been approved for use in PrEP. The study will provide participants with either Truvada or F/TAF, along with an identical placebo pill and will be required to take both the active medication and placebo every day.

DISCOVER #PrEP trial for #HIV prevention in gay men and Trans women recruiting participants at Mater Hospital [email protected] for more info.

— CEPHR_UCD (@CEPHR_UCD) December 20, 2016

F/TAF vs Truvada

The potential benefits of using F/TAF for PrEP are that TAF has less of an effect on bone density and renal (kidney) function when compared with TDF in Truvada, while still providing a high level of tenofovir in the blood.

Studies on simians have indicated that F/TAF is effective at preventing SHIV (a virus combining simian and human immunodeficiency virus) from being contracted.

However another F/TAF study in women found that the active level of Tenofovir found in vaginal and rectal tissue was not as high as with F/TDF.

In those women who had taken F/TAF, the level of tenofovir in rectal tissue was about 10 times lower than could be expected from women who had taken F/TDF at the same levels, while the level of tenofovir in vaginal tissue from F/TAF was half of that found in women who had taken F/TDF.

Dosage

Despite the fact that taking F/TAF means that there is a lower level of tenofovir in rectal tissue, the dosage of TAF is not being altered in this trial to compensate for that. The Irish trial calls for a 25mg dose of TAF in the F/TAF combination, compared with a 300mg dose of TDF in the Truvada (F/TDF) combination.

It is as of yet unclear whether HIV protection is garnered from high levels of tenofovir in the blood, in rectal and vaginal tissues or a combination of both.

The trial will last for 144 weeks, or two and three-quarter years, and will require regular trips to the doctor roughly every three months for continued monitoring.

For more information about the Irish PrEP study being run by UCD and The Mater, email [email protected].