What are DHHS guidelines for pre-exposure prophylaxis (PrEP) antiretroviral therapy against HIV infection?

Updated: Apr 18, 2019
  • Author: R Chris Rathbun, PharmD, BCPS (AQ-ID), AAHIVP; Chief Editor: John Bartlett, MD  more...
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Pre-exposure prophylaxis (PrEP) consisting of daily, oral tenofovir DF 300 mg and emtricitabine 200 mg is recommended for all adults and adolescents (≥35 kg) with substantial risk for acquiring HIV. [137]  This is not dependent upon transmission risk factor and is recommended for men who have sex with men (MSM), heterosexual men and women, and people who use intravenous drugs (PWID). [137] In the U.S., the FDA approved agent for PrEP is Truvada®, a fixed dose combination tablet of tenofovir DF 300 mg/emtricitabine 200 mg. [137]

Studies across these patient populations have shown a significant decrease in rates of new HIV infection with the use of PrEP therapy. The first published trial, a multinational study called the Pre-exposure Prophylaxis Initiative (iPrEx) trial, found that once-daily tenofovir DF/emtricitabine reduced the risk of acquiring HIV by 44% in a study population of high-risk, HIV-negative men or transgender women who have sex with men. [138]   The Partners PrEP trial, examining HIV transmission rates among discordant heterosexual couples in Uganda and Kenya, showed a combined efficacy rate of 75%. [139]  Among PWID, 2,413 people were included in the Bangkok Tenofovir Study. The study utilized only tenofovir DF therapy and was conducted at drug treatment clinics as part of a more comprehensive risk-reduction program. Tenofovir DF use was associated with a 48.9% reduction in HIV acquisition. [140]  Most recently, the Adolescent Medicine Trials Network for HIV/AIDS study 113 looked at safety and efficacy in a small patient population of 15 to 17 year olds. The study found that when used correctly, tenofovir DF/emtricitabine was effective at reducing HIV infection without significant increases in toxicity. The study also reported decreasing adherence over time, suggesting adolescents may need more intervention and monitoring while on PrEP therapy. [141]

Adherence is essential in efficacy. In studies, the level of protection varied widely depending on how consistently participants used PrEP. [137] In fact, some studies with very poor adherence showed no reduction in incidence with the use of tenofovir DF or tenofovir DF/emtricitabine. [142, 143]  Among those whose data indicate use on 90% or more days (based on self-reports, bottles dispensed, and pill counts), HIV risk was reduced by 73%. Among those whose adherence by the same measure was less than 90%, HIV risk was reduced by only 21%. [137] Comprehensive prevention services are also required (i.e., monthly HIV testing, condom provision, counseling, and management of other sexually transmitted infections).

Guidelines recommend limiting PrEP to a 90-day supply to allow for optimal follow-up and monitoring. At each visit, patients should be tested for HIV infection and monitored for signs and symptoms of acute infection. In addition, adverse effects, adherence, and risk-reduction behaviors should be discussed. Creatinine clearance monitoring and repeat sexually-transmitted infection testing should occur at least every 6 months but may be done every 3 months if warranted. [137]

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