A monthly vaginal ring and a daily oral tablet, both containing anti–HIV drugs, were safe and acceptable in studies of adolescents, two teams of investigators reported at the 9th IAS Conference on HIV Science. The experimental ring is designed for HIV prevention and the oral tablet is already used for this purpose in adults. Adherence to the ring was high, while adherence to the tablet was moderate and diminished substantially when study visits became less frequent. These studies mark the first time the vaginal ring was tested in adolescent girls younger than 18 years and the first time a clinical trial of the oral tablet as pre–exposure prophylaxis (PrEP) specifically for adolescents included girls.

Both trials were funded in part or in whole by NIAID. The study of oral PrEP – called Choices for Adolescent Prevention Methods for South Africa, or CHAMPS PlusPills – is only the second clinical trial to report results of PrEP focused solely on adolescents. The NIAID–funded Phase 2 study evaluated the safety, acceptability and use of daily oral Truvada, which contains two anti–HIV drugs, as part of an HIV prevention package for this age group. Truvada is not yet approved by any national regulatory body for use as oral PrEP in adolescents.

CHAMPS PlusPills involved 148 healthy, sexually active, HIV–uninfected South African 15– to 19–year–olds in Cape Town and Johannesburg. The group included 99 girls and 49 boys. Participants were asked to take daily oral Truvada for at least three months and up to one year if they chose to do so.

The researchers found that most participants chose to take daily oral Truvada. Although the number of participants who actually took Truvada as prescribed was lower than the number who opted in and decreased over time, nearly 40 percent were adherent by the end of the study. Only one participant became infected with HIV during the trial, a 19–year–old who had stopped taking Truvada three months before her HIV diagnosis.

During the first three months of the trial, participants had monthly study visits, and subsequent visits occurred quarterly. Participants could choose to opt out of, continue or resume taking Truvada for PrEP at every quarterly visit. All participants were followed for the entire study year.

At three months, tenofovir was detectable in the blood samples of 57 percent of participants, and 82 percent of participants opted to continue taking Truvada for PrEP. At six months, tenofovir was detectable in the blood samples of 38 percent of participants, and 64 percent opted to continue or resume taking Truvada. Sixty–four percent of participants also opted to continue or resume taking Truvada at nine months. At the end of the year, 38 percent of participants tested positive for tenofovir. Participants frequently cited low–grade side effects, such as nausea or headache, as the reason they stopped taking Truvada as oral PrEP.

The HIV prevention package given to all CHAMPS PlusPills study participants included HIV testing, management of sexually transmitted infections, counseling on how to reduce the risk of acquiring HIV, access to condoms, post–exposure prophylaxis, and counseling on the ongoing need for Truvada as oral PrEP.

In addition, investigators offered three optional HIV prevention components designed specifically for adolescents. Participants could elect to receive daily or weekly text messages reminding them to take their Truvada and querying if they encountered a problem. Participants also could join adherence clubs. Finally, participants could receive real–time reports of the level of tenofovir in their blood during study visits.

The study results contribute to a growing body of data that could support the development of evidence–based guidelines for the use of Truvada as oral PrEP in adolescents.