Although preexposure prophylaxis was found to be safe and well tolerated among adolescent men who have sex with men at increased risk of HIV, rates of medication adherence decreased over time.
“Several open-label clinical trials and demonstration projects have supported the effectiveness of administering daily oral preexposure prophylaxis based on three studies that demonstrated efficacy for preventing HIV,” Sybil G. Hosek, PhD, from the Stroger Hospital of Cook County, and colleagues wrote. “None of these clinical trials included adolescent participants younger than 18 years, precluding regulatory agencies from considering the approval of tenofovir disoproxil fumarate/emtricitabine use for minors.”
To assess the safety and compliance with a preexposure prophylaxis (PrEP) routine in adolescent men who have sex with men (MSM), as well as the adherence to changes in sexual risk behaviors, the researchers conducted a demonstration project that included HIV-negative adolescent MSM between the ages of 15 and 17 from six adolescent medicine clinics and community partners throughout the United States.
Each participant was exposed to an individualized evidence-based behavioral intervention and was administered tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) for PrEP daily over the course of 48 weeks. The researchers measured levels of the drug in dried blood spots to determine safety, rates of adherence, patterns of use and acceptability.
Of the 78 teenagers enrolled (SD age, 16.5 [0.73] years), 3% were Asian/Pacific Islander, 29% were black, 14% were white, 21% were Hispanic an 33% were of other or of mixed race/ethnicity. Twelve participants were diagnosed with 23 sexually transmitted infections during PrEP use, and the seroconversion rate for HIV was 6.4 (95% CI: 1.3-18.7) per 100 person-years.
At 4 weeks, 54% of participants had levels of TDF/FTC that suggested high levels of anti-HIV prevention. At 8 weeks, 47% sustained these levels, and at 12 weeks, 49% had TDF/FTC levels suggestive of HIV prevention. Lower percentages were observed in later weeks, with 28% achieving levels of anti-HIV prevention at 24 weeks, 17% at 36 weeks and 22% at 48 weeks.
“Challenges with adherence to medication are commonplace among adolescents, regardless of whether it is adherence to a treatment or prevention regimen,” Hosek and colleagues wrote. “ … Most participants were able to take at least two doses per week as estimated by TFV-DP levels, indicating that they were attempting to adhere to the regimen, albeit with less frequency than prescribed. Of critical importance will be the development and testing of long-acting PrEP agents for HIV prevention among adolescents that would likely reduce, but not eliminate, the adherence issues that are associated with daily pills.” – by Katherine Bortz
Disclosure: Mayer receives grant support from Gilead Sciences and ViiV. Anderson receives donated study drugs and contract work fees from Gilead. No other disclosures were reported.