Episode Details

Episode 213: HIV PrEP Review

H. Nicole Magaña, medical student, reviews the history of PrEP and outlines the currently FDA-approved medications used for HIV prevention. Dr. Arreaza provides additional perspective on long-acting injectable options, including how quickly they begin to protect patients after initiation.  

Written by Nicole Magana, MSIV, American University of the Caribbean. Comments and edits by Hector Arreaza, MD.

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Pre-exposure prophylaxis for HIV.

Previous episodes related to HIV: 
-Episode 67, HIV history (September 2021)
-Episode 68, HIV transmissibility (October 2021)
-Episode 70 (October 2021), HIV prevention (including HIV Prep with oral medications)
-Episode 98 (June 2022), we introduced Apretude, the first injectable for HIV PrEP. Apretude was approved in December 2021. 

What is Pre-Exposure prophylaxis (PrEP)?

Pre-exposure prophylaxis, or PrEP, is the use of antiretroviral medications taken by individuals who are HIV-negative to prevent HIV acquisition. There are 30,000 new HIV infections annually in the US. 

How effective is it?

When taken as prescribed, PrEP is highly effective at reducing the risk of HIV transmission through sexual exposure and injection drug use. Patients who are adherent to PrEP can lower their risk of contracting HIV by 99%.

The effectiveness of oral PrEP is highly adherence dependent. In trials with 70% adherence, the relative risk of HIV acquisition was 0.27, compared to 0.51 with 40-70% adherence and no significant benefit with adherence ≤40%.

How does PrEP work?

PrEP works by maintaining therapeutic drug levels in the bloodstream and in target tissues. If HIV exposure occurs, viral replication is inhibited, preventing the establishment of infection.

Brief History of PrEP.

The concept of PrEP originated from early animal studies demonstrating that antiretroviral medications could prevent retroviral transmission when administered before exposure.

In 2010, the iPrEx trial showed that daily oral tenofovir disoproxil fumarate (known as Truvada) with emtricitabine significantly reduced HIV acquisition among men who have sex with men and transgender women. This was the first large clinical trial to demonstrate the effectiveness of PrEP.

In 2012, the FDA approved oral Truvada, which is TDF/FTC (tenofovir disoproxil and emtricitabine) for HIV prevention. Since then, additional studies have expanded indications and introduced new formulations, including long-acting injectable options.

Who Should Be Offered PrEP?

PrEP should be considered for any HIV-negative individual at increased risk of HIV acquisition, including Men who have sex with men, transgender individuals, heterosexual men and women with an HIV-positive partner, individuals with recent bacterial sexually transmitted infections, people who inject drugs, individuals engaging in condomless sex with partners of unknown HIV status.

Remember that PrEP should be offered in a nonjudgmental, patient-centered manner, make it a safe space to talk openly about prevention of HIV. 

Available HIV PrEP Options.

Daily Oral PrEP: There are 2 formulations of Tenofovir. There is Tenofovir disoproxil fumarate (TDF)/ Truvada and Tenofovir alafenamide (TAF)/ Descovy. Each is available in a tablet combined with Emtricitabine a nucleoside reverse transcriptase inhibitor.