- Category: Pre-exposure Prophylaxis (PrEP)
- Published on Tuesday, 05 January 2016 00:00
- Written by Liz Highleyman
HIV incidence was "extremely low" in a pre-exposure prophylaxis (PrEP) demonstration project at community-based clinics in Miami, San Francisco, and Washington, DC, and no new infections were seen among gay and bisexual men who took Truvada (tenofovir/emtricitabine) at least twice a week, according to a report in the January 26 edition of JAMA Internal Medicine. PrEP adherence was higher among people at greater risk for HIV.
After PrEP using daily Truvada demonstrated high efficacy for men who have sex with men and transgender women in the international iPrEx trial, Alfred Liu from the San Francisco Department of Public Health and colleagues designed the PrEP Demo Project to explore its effectiveness in real-world clinical practice. Results from the study were previously reported in part at the 2015 International AIDS Society Conference on HIV Pathogenesis, Treatment, and Prevention last July.
The PrEP Demo Project was conducted between October 2012 and February 2015 at 3 sites: the Miami-Dade County Downtown STD Clinic, San Francisco City Clinic, and Whitman Walker Health in Washington, DC. Together the sites enrolled 557 participants at risk for HIV infection. Just over half came to the clinics seeking PrEP themselves while the rest were referred by providers. Before PrEP the annual HIV seroconversion rate among gay men at these clinics exceeded 2%.
Most participants (550) were gay or bisexual men and 7 were transgender women. The average age was 35 years, with one-fifth being under 25. Nearly half (48%) were white, 35% were Latino, 7% were black, and 10% were mixed or other race/ethnicity. About three-quarters reported recreational drug use. Risk factors included condomless anal sex with 2 or more partners, anal sex with HIV-positive partners (including about a quarter with a positive primary partner), or having sexually transmitted infections (STIs). About a quarter had gonorrhea, syphilis, or chlamydia at initial screening. Participants were required to have normal kidney function at baseline as tenofovir can cause kidney impairment.
All participants received free daily Truvada pills on an open-label basis (not randomized) for 48 weeks. They had follow-up visits at 1, 3, 6, 9, and 12 months for HIV and STI testing, clinical monitoring, counseling, and PrEP dispensing.
- 3 people were found to have acute HIV infection at study enrollment.
- 2 participants were newly infected with HIV during follow-up, for an incidence rate of 0.43 per 100 person-years; both had blood drug levels suggesting they took PrEP less than twice a week.
- 79% of enrolled participants were still taking PrEP at the end of the 12-month study period.
- About 15% of participants interrupted PrEP -- in many cases temporarily -- mostly due to side effects (e.g., nausea, headache) or perceived low risk.
- Adherence, as determined by tenofovir drug levels in dried blood spots, was about 85% overall, based on prior studies indicating that 4 doses a week offers a high level of protection.
- While adherence reached 90% in San Francisco and 88% in Washington, DC, it was only 65% in Miami.
- White participants reached 91% adherence, compared with 77% for Latinos and 57% for black participants.
- Being homeless or having unstable housing predicted poorer adherence, but age, education level, and alcohol or drug use did not.
- Participants who reported condomless anal sex with more partners had better adherence (89% if 2 or more partners vs 75% if 0-1 partners during the past 3 months).
- The mean number of anal sex partners declined during follow-up, from 10.9 to 9.3.
- The proportion of people who had condomless receptive anal sex remained stable at around 66%, but participants were less likely to report sex with condoms as their length of time on PrEP increased.
- Overall STI incidence was high (90 per 100 person-years) but did not increase over time; Liu previously reported that the number of participants with STIs decreased during the first 6 months on PrEP but then rose again to the baseline level.
- PrEP safety and tolerability was generally good, with no serious adverse events considered related to Truvada.
- Less than 5% of participants experienced mild or moderate creatinine elevations (a potential sign of kidney function impairment), but these resolved without stopping Truvada.
"The incidence of HIV acquisition was extremely low despite a high incidence of STIs in a large U.S. PrEP demonstration project," the study authors concluded. "Adherence was higher among those participants who reported more risk behaviors. Interventions that address racial and geographic disparities and housing instability may increase the impact of PrEP."
AY Liu, SE Cohen, E Vittinghoff, et al. Preexposure Prophylaxis for HIV Infection Integrated with Municipal- and Community-Based Sexual Health Services. JAMA Internal Medicine 176(1):75-84. January 2016.