April 12, 2018
5 min read

Researchers ID four types of nonbiomedical PrEP failure

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HIV pre-exposure prophylaxis, or PrEP, is effective. In high-risk patients, it can reduce the risk for HIV by up to 92%, according to the CDC. But the medication is far less effective when not taken consistently, and understanding the barriers to PrEP uptake and adherence has been a major focus of research for years.

In the United States, no group is at a higher risk for HIV than black men who have sex with men (BMSM), making them prime candidates for PrEP. But awareness, access, uptake and adherence to therapy remain low among BMSM, according to David P. Serota, MD, infectious diseases fellow at Emory University School of Medicine, and colleagues.

Based on findings from a cohort of HIV-negative, young BMSM in Atlanta, Serota and colleagues described five types of PrEP failure — reasons why the medication fails to protect patients. These include rarely reported biomedical failures — when patients acquire HIV despite adhering to their medication — and four patient behaviors.

BMSM — especially in the southeastern U.S. — have the highest HIV incidence of any group in the country, “but have less PrEP awareness, less self-reported PrEP use, and less persistence on therapy than white MSM,” Serota and colleagues wrote in Clinical Infectious Diseases.

“Although black persons make up 44% of new HIV infections, they made up only 10% of people taking PrEP in 2016,” they wrote. “The gaps in PrEP use among young BMSM could exacerbate the existing disparities in HIV incidence. Thus, it is imperative that we address gaps in the PrEP continuum of care.”

In June 2017, Serota and colleagues enrolled 300 young HIV-negative BMSM in Atlanta aged 16 to 29 years who reported at least one male sexual partner in the past 3 months and offered them access to free PrEP. Participants will be followed prospectively for 2 years, during which time they will receive comprehensive HIV/STI testing and risk-reduction counseling and be surveyed about their HIV prevention behaviors and risk factors, Serota and colleagues said.

By December, 14 study participants had acquired HIV, including five who reported no interest in PrEP, five who were interested but had not started taking it before seroconversion and four who had taken PrEP. Among those taking PrEP, Serota and colleagues reported one apparent case of biomedical failure in a patient who may have had acute HIV at the time of PrEP initiation or was exposed to the virus before achieving protective drug levels. Another patient had low adherence and two discontinued therapy.

Based on the 14 new cases, Serota and colleagues identified four other types of PrEP failure and suggested interventions to address each:

  • Low PrEP adherence: One patient in the study became infected after not bringing his medication on several trips. Serota and colleagues listed several interventions to address low adherence, such as therapeutic drug monitoring, which has been shown to work.
  • PrEP discontinuation: This may occur on an intermittent or permanent basis for personal or medical reasons and can be distinguished from nonadherences by whether patients consider themselves to be “on PrEP,” Serota and colleagues said. “In our experience, participants who stop PrEP during periods of abstinence or low risk often wish to reinitiate once they have already re-engaged in high-risk behavior, whereas ideally, PrEP should be reinitiated prior to high-risk behavior,” they wrote. “PrEP programs should focus on making it easier to access necessary laboratory testing and obtaining new prescriptions in order to decrease barriers to PrEP re-initiation.”
  • PrEP contemplation: According to Serota and colleagues, this is when patients express interest in PrEP but do not start taking it before becoming infected. They said more research is needed to identify methods to get patients who are contemplating PrEP to begin taking it. “We have noted that participants’ interest in PrEP waxes and wanes throughout the study; thus, it is important to continually re-offer PrEP over time,” they wrote.
  • PrEP refusal: Serota and colleagues identified several reasons that patients refuse to take PrEP, including low self-perceived risk. They called for evidence-based approaches that frame PrEP in a positive light and messages that focus on health promotion instead of risk mitigation. “Although patient autonomy should be respected and validated, it remains important to identify and understand reasons for refusal to improve messaging and education about this proven intervention,” they wrote.

Serota and colleagues also identified systems failures, or “structural contributors to PrEP failure that are not explicitly related to the individual patient or provider,” including lack of health insurance, limited access to affordable health care, patient assistance program requirements, stigma, low self-efficacy, low health literacy, provider unfamiliarity with PrEP, and medication cost. They offered study participants free rides and frequent reminders about PrEP initiation but were unable to provide same-day PrEP initiation or walk-in appointments, which they said could increase uptake. They listed other barriers, including issues related to cost and obtaining proper documentation to qualify for assistance programs.

“Although we believe PrEP should be available to all who are at risk of acquiring HIV without medical contraindication, it is clear that increasing awareness and access to PrEP alone are inadequate,” Serota and colleagues concluded. “By identifying and addressing specific contributors to low PrEP adherence, PrEP discontinuation, PrEP contemplation, and PrEP refusal, we can ensure that all who desire PrEP can achieve optimal efficacy and realize reductions in population HIV incidence.” – by Gerard Gallagher

Editor’s note: Truvada (tenofovir disoproxil fumarate/emtricitabine , Gilead Sciences ) is the only drug approved for HIV PrEP in the United States .

Disclosures: Serota reports grants from National Center for Advancing Translational Sciences during the conduct of the study. Please see the study for all other authors’ relevant financial disclosures.