PrEP therapy to reduce risk of HIV infection is safe, effective in teen males

In a diverse sampling of adolescent men who have sex with men (MSM) at high risk for HIV, preexposure prophylaxis (PrEP) with tenofovir disoproxil fumarate/emtricitabine (TDF/FTC)—approved only in adults—was safe and well tolerated, with 54% achieving protective drug levels during monthly visits, although adherence decreased with quarterly visits, according to a study published in JAMA Pediatrics.

“Several studies have shown that daily oral PrEP is effective in preventing HIV among people at high risk of becoming infected, but none of them included adolescents under age 18,” said author Bill Kapogiannis, MD, National Institute of Child Health and Human Development (NICHD), Maternal and Pediatric Infectious Diseases Branch, Rockville, MD. “Our study suggests that this therapy can safely reduce HIV risk for those under 18.”

Project PrEPare (Adolescent Medicine Trials Network for HIV/AIDS Interventions 113) was a PrEP demonstration project to evaluate the safety, tolerability, and acceptability of TDF/FTC and usage patterns, adherence rates, and sexual risk behavior patterns in healthy, young MSM, aged 15 to 17 years.

Dr. Kapogiannis and fellow researchers conducted this study to assess the safety of, and adherence to, PrEP among adolescent MSM, as well as changes in their sexual risk behavior. They recruited subjects from adolescent medicine clinics in 6 US cities. All subjects had negative HIV test results, but were considered high risk for acquiring an infection.

Subjects were required to complete an individualized evidence-based behavioral intervention, and given TDF/FTC daily as PrEP for 48 weeks. In all, 260 of 2,864 screened subjects were eligible, and 78 were enrolled (mean age: 16.5 years; 3% Asian/Pacific Islander; 29% African American; 14% white; 21% white Hispanic; 33% mixed).

During the 48 weeks of PrEP use, 23 sexually transmitted infections were diagnosed in 12 subjects. Three subjects were diagnosed with HIV during the study, one each at weeks 32, 36, and 48. All three had no detectable blood levels of TDF/FTC at the visit before HIV diagnosis, which indicates that they were likely missing doses or not taking the medication at all.

The HIV seroconversion rate was 6.4 (95% CI: 1.3, 18.7) per 100 person-years. Fifty-four percent demonstrated tenofovir diphosphate levels that were consistent with a high degree of antiHIV protection ( > 700 fmol/punch) at week 4; this decreased to 22% by week 48.

As the study progressed, many subjects began skipping doses. The primary reason given for this was worrying that “others will see me taking pills and think I am HIV-positive.” Other reasons included 32% who cited being away from home, 28% too busy, 26% forgetting, and 19% changes in routine.

These researchers noted that the tendency of young persons to skip medications highlights the need for more contact with clinical staff during therapy, as well as the need for effective strategies to ensure that the medication is taken as prescribed.

“The high incidence rates of HIV and STIs among YMSM, along with the lack of any significant safety signals from this study, strongly support the need for an adolescent PrEP indication for TDF/FTC. The waning adherence, especially with quarterly visits, demonstrates that more time, attention, and resources may need to be allocated to adolescents who are seeking prevention services. Developmentally appropriate visit schedules within adolescent-friendly service facilities will be important additions to PrEP implementation programs,” concluded these authors.

This study was funded by NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institute on Drug Abuse, and National Institute of Mental Health.