DURBAN, SOUTH AFRICA – Oral emtricitabine/tenofovir for pre-exposure prophylaxis against HIV acquisition in high-risk 15- to 17-year-old males proved safe and effective in the first clinical trial looking at the drug’s effects in a population so young, Sybil Hosek, PhD, reported at the 21st International AIDS Conference.
Based upon these encouraging findings, the drug’s manufacturer, Gilead Sciences, plans to file a request for the Food and Drug Administration to grant an expanded indication for emtricitabine/tenofovir (Truvada) for pre-exposure prophylaxis (PrEP) against HIV infection in teens as young as 15 years. The drug is currently approved for use only in patients aged 18 and up because there were no data in younger patients, said Dr. Hosek of John H. Stroger, Jr. Hospital, Chicago.
Dr. Sybil Hosek
The prospect of an expanded indication in younger adolescents is most welcome news, she added.
“I really want to strongly, strongly, strongly say that adolescents need access to PrEP,” Dr. Hosek declared. “This is one of the best prevention options we’ve had in a long time.”
Co-investigator Craig M. Wilson, MD, concurred. “The epicenter of the HIV/AIDS epidemic in the U.S. is in 13- to 24-year-old males who have sex with males, particular MSM of color,” noted Dr. Wilson, professor of epidemiology, pediatrics, and director of the Sparkman Center for Global Health at the University of Alabama, Birmingham.
Dr. Hosek reported on 77 male teens ages 15-17 at high self-reported risk for HIV infection because of behaviors such as condomless anal intercourse with an HIV-positive or unknown-status partner. All 77 were negative for HIV at enrollment, which didn’t require parental permission. Prior to embarking on 48 months of once-daily, open-label emtricitabine/tenofovir for PrEP in this multicenter U.S. trial, they received personalized risk reduction, adherence, and behavior counseling. As part of the study protocol they had clinic visits monthly for the first 12 weeks. At that point the visits, which included testing for HIV and other STIs as well as measurement of blood drug levels as an indicator of adherence, were scaled back to once every 3 months.
Dr. Craig M. Wilson
The PrEP was safe and well tolerated. No one discontinued treatment because of side effects. The only adverse event of note was weight loss of 10%-19% in two patients. New STIs were diagnosed and treated in 12.3% of participants in the first 24 weeks of the study and in 10.6% in the next 24 weeks.
Three patients seroconverted during the 48-week study, for a hefty HIV infection rate of 6.41% per year. One of these patients never took the PrEP medication, the other two did so on and off but had no or very low blood levels of the drug at the time of seroconversion.
Adherence was a major issue, according to Dr. Hosek. She deemed adherence to be “really good” during the first 12 weeks of the study. During that period, the majority of participants had blood levels indicating they were taking their medication at least 4 days per week, providing high-level protection. More than 95% of subjects had detectable levels of drug, indicating they were at least trying to keep up with their medication schedule. However, once the clinic visits were scaled back from monthly to quarterly, adherence fell off drastically.
Audience member Carlos del Rio, MD, commented that he found the poor adherence over time to be really discouraging.
“The adolescent challenge is tremendous. All the studies show us that this group isn’t getting any protection. Are we trying to fit a square peg in a round hole? Is this something that’s just not going to happen, so we should look at alternatives such as long-acting injectables? It looks to me like we’re not going to get the adherence we need in adolescents with any of the things that are out there at this moment,” said Dr. del Rio, professor and chair of the department of global health and codirector of the center for AIDS research at Emory University in Atlanta.
Dr. Hosek replied that she found heartening the “outstanding” treatment adherence rate when patients were being seen monthly.
“Young people need more time,” Dr. Hosek observed. “And if they need that time from us, we have to give it to them. If they need to see us more frequently, if they need to text with us, if they need interim phone calls, a peer support group, an adherence club – whatever they need, if they want PrEP and they want to make it work, then we need to help them make it work. That’s our responsibility, to give them the time and attention they need.”