PrEP for People Who Inject Drugs
Around the world, people who inject drugs are among the most marginalized and at risk for HIV infection. Results from the Bangkok Tenofovir Study, published online yesterday in the journal Lancet, support adding PrEP (pre-exposure prophylaxis) to the HIV-prevention tool box for people who inject drugs.
The study authors, led by Kachit Choopanya, MD, note that daily oral tenofovir reduced the risk of HIV infection in injection drug users (IDUs) by nearly 49% overall—and up to 74% among those who took the study drug via directly observed therapy during clinic visits.
This is the first study to assess whether PrEP helps prevent HIV infection in this risk group. “Pre-exposure prophylaxis with tenofovir can now be considered for use as part of an HIV prevention package for people who inject drugs,” Choopanya and colleagues state.
While the study results are certainly welcome news, it’s still unclear whether tenofovir PrEP specifically prevents “parenteral” HIV acquisition—that is, acquisition through injection rather than sex. “Because no biological marker exists to distinguish between HIV transmission that occurs through sex and that which occurs parenterally, all HIV infections during follow-up in this trial contribute to the overall efficacy measure,” notes HIV prevention researcher Salim Abdool Kareem, MD, PhD, in a comment accompanying the Lancet article.
Therefore, Kareem adds, “it is not possible to make definitive conclusions about the efficacy of daily tenofovir for the prevention of parenteral transmission of HIV from these data. As a result, PrEP is not a replacement for politically sensitive needle exchange programmes to prevent parenteral transmission.”
The U.S. Centers for Disease Control and Prevention today issued updated interim guidance for the use of PrEP, now including the recommendation that health care providers offer the drug Truvada—the combination pill already approved for both HIV treatment and PrEP—to their IDU patients as part of an HIV prevention package that also addresses other health issues (although the guidance makes no mention of needle exchange).
“Providing PrEP to IDUs at very high risk for HIV acquisition could contribute to the reduction of HIV incidence in the United States,” the CDC guidance observes. “In addition, if PrEP delivery is integrated with prevention and clinical care for the additional health concerns faced by IDUs (e.g., hepatitis B and C infection, abscesses, and overdose), substance abuse treatment and behavioral health care, and social services, PrEP will contribute additional benefits to a population with multiple life-threatening physical, mental, and social health challenges.”
The CDC’s comprehensive U.S. guidelines on the use of PrEP for men who have sex with men, heterosexual men and women, and people who inject drugs is anticipated later this year.
The Lancet article is available only to journal subscribers, but you can read the abstract here, and the CDC’s fact sheet about the Bangkok Tenofovir Study can be downloaded here. To learn more about the study and its implications, join the informational webinar hosted by AVAC and the Harm Reduction Coalition on Tuesday, June 18, at 10:00 a.m. Eastern Time. Get the details and register.
Reilly O’Neal is a freelance writer and former editor of BETA.
Choopanya, K. and others. Antiretroviral prophylaxis for HIV infection in injecting drug users in Bangkok, Thailand (the Bangkok Tenofovir Study): a randomised, double-blind, placebo-controlled phase 3 trial. Lancet [Epub ahead of print]. June 13, 2013.
Smith, D. and others. Update to interim guidance for preexposure prophylaxis (PrEP) for the prevention of HIV Infection: PrEP for injecting drug users. Morbidity and Mortality Weekly Report 62(23):457–88. June 14, 2013.