Review finds PrEP can prevent HIV when those at-risk have access, and are adherent to the treatment.
James Riddell IV, MD
One tablet a day can prevent being infected with HIV, but a recent review finds that few of the estimated 1.2 million at-risk adults in the US are receiving this protection.
"There is a need to provide additional interventions beyond encouraging condom use and needle exchange to prevent HIV Infection," James Riddell IV, MD, Division of Infectious Diseases, Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor, MI told MD Magazine. "The use of tenofovir/emtricitabine as chemoprophylaxis, known as PrEP to prevent transmission, is yet another tool to decrease transmission."
The antiretroviral combination tablet of tenofovir disoproxil fumarate (TDF)/emtricitabine (Truvada, Gilead) has proven effective in a variety of populations, and is US Food and Drug Administration (FDA)-approved for pre-exposure prophylaxis (PrEP) for HIV. Most of the individuals who could benefit are not prescribed the medication, however, and many others are unable to obtain it or don't continue to take it as directed.
Riddell and colleagues, Rivet Amico, PhD Department of Health Behavior and Health Education, University of Michigan School of Public Health, Ann Arbor and Kenneth Mayer, MD, The Fenway Institute, Fenway Health, Boston, MA, found in their review that practitioners must conduct thorough, periodic reviews of patients' sexual and drug use patterns to identify appropriate candidates for PrEP.
"Primary care physicians are well positioned to identify high-risk patients and prescribe PrEP," Riddell and colleagues observed, adding, "as PrEP is prescribed by a more diverse group of clinicians such as primary care physicians, specialists and clinicians providing care at sexually transmitted infection (STI) clinics and community health centers, more at-risk patients can benefit."
Riddell and colleagues identified several factors that could contribute to reluctance of practitioners to prescribe the treatment, including unfamiliarity with the International Statistical Classification of Diseases and Related Health Problems, 10th Revision (ICD-10) codes that are applicable to the patient visit. Additional aspects of treatment that could represent obstacles, they suggest, are the follow-up visits and labs every 3 months to determine HIV status, screen for bacterial STI, monitor renal function and ascertain adherence to medication directions.
"Since adherence predicts efficacy, it is essential to ask about adherence and discuss its importance at each clinical visit," Riddell and colleagues emphasized. "Adherence is usually assessed at the time of each quarterly interview by simply asking patients how many doses they have missed each week or month."
In addition to 2 studies supporting the FDA approval of PrEP, subsequent controlled trials in varying populations, and open-label and demonstration projects investigating strategies for wider implementation, Riddell and colleagues examined possible future PrEP modalities. These included an intravaginal ring containing dapivirine, a nonnucleoside reverse transcriptase inhibitor; an injectable, long-acting formulation of cabotegravir, an integrase strand transfer inhibitor; and immunoprophylaxis with broadly neutralizing monoclonal antibodies (bnAbs), which inhibit the replication of more than 1 strain of HIV.
In the near term, however, they note that oral TDF/emtricitabine is the only available PrEP modality.
"Overall, we feel that if Truvada is more widely prescribed, we can finally create an inflection point and finally observe a significant decrease in the number of new people infected with HIV," Riddell said.
The review of HIV preexposure prophylaxis was published in the March 27 issue of the Journal of the American Medical Association.