ART effective for HIV prevention in couples

'A very powerful and desirable strategy'

The search for an HIV vaccine will continue, but in the meantime, there is little doubt that an aggressive HIV screening and early treatment strategy could make a big impact on reducing HIV transmission. The latest study to show success with using antiretroviral therapy (ART) to prevent HIV transmission had such early and dramatic results that it was halted early.

This new research also emphasizes the importance of adjusting public health policies to support long-term ART adherence.

"This is the largest prevention benefit ever reported in the HIV prevention field," says Myron Cohen, MD, director of the Institute for Global Health and Infectious Diseases at the University of North Carolina at Chapel Hill. Cohen is an investigator on the study and also is a professor of medicine, microbiology and public health at UNC.

The National Institutes of Health (NIH) announced in May, 2011, that an HIV Prevention Trials Network study, titled HPTN 052, found the risk of transmitting the virus to uninfected sexual partners could be reduced by 96% if the HIV-positive partner adhered to an effective antiretroviral therapy (ART) regimen.

"The HPTN study will fuel the argument that treatment might be one of the most effective and scalable prevention interventions for individuals and populations, but [the lack of] resources will be the argument thrown at that strategy," says Susan Little, MD, professor of medicine at the University of California — San Diego (UCSD).

"It might be cost-effective, but it's not inexpensive," she adds.

HPTN 052 took place at 13 sites in nine countries, enrolling 1,700 sero-discordant couples, including 900 couples in sub-Saharan Africa. It began in May, 2007, and continued through April, 2011, Cohen says. The study enrolled people living with HIV with a CD4 cell count between 350 and 550. The couples enrolled had to be in a stable relationship and have sex on a regular basis. Those enrolled were not eligible for treatment according to the latest international guidelines of the time.

The results were tremendously satisfying, demonstrating a quick and rapid reduction in sexual transmission of HIV among those receiving ART, Cohen says.

"It was assumed we wouldn't see a difference in infection rates until 2015," Cohen says. "But the data safety monitoring board that oversees the study met on April 28, 2011, and they recommended that the results be made public."

There was one case of HIV transmission in the ART arm and 27 cases of HIV transmission in the delayed treatment arm, he says.

Each couple enrolled in the study received counseling and condoms, and their rates of transmission were low historically.

"Even with very low rates of transmissions, ART offers greater than 96% prevention from transmission," Cohen says. "So we decided to essentially stop randomization and offer treatment to people in the delayed arm."

The immediate issue is how to counsel discordant couples about HIV prevention, Cohen says.

"We still have to talk about safe sex and condoms," he adds. "And there were 11 unlinked transmission events, showing that ART is not going to help someone who is having sex with someone else who might be infected."

The new normal

The study's findings underscore the importance of adjusting treatment and prevention policies and reimbursement to reflect the reality of HIV-infected patients living long and productive lives, says James M. Sosman, MD, FACP, medical director of the HIV care program, division of general medicine and infectious diseases, and associate professor of medicine at the University of Wisconsin School of Medicine and Public Health in Madison, WI.

Research has come full circle, showing improved health benefits, reduced risk of serious morbidity and mortality, fewer common side effects, and now, significantly lower HIV transmission, when ART is initiated early.1

All of this suggests that policy changes involving economics need to center on the reality that people are going to be starting ART earlier and taking it for much longer, Sosman says.

"Now we have data that really show that treatment is prevention," he says. "And that means we need HIV patients to maintain impeccable adherence to reduce the risk of new infections."

Newly-infected individuals have high viral loads and are more likely to transmit HIV, Little says.

"Those with new infections have much higher levels of virus in their blood than people at any other stage of infection," she adds. "And people with new infection are often unaware of their diagnosis because they've been infected for a short period of time."

These facts and the new data emphasize the importance of early detection and links to medical care. While this is something the Centers for Disease Control and Prevention (CDC) has been promoting for five years, it hasn't translated into routine HIV testing in medical settings, Sosman says.

It takes time to bring a change in policy and practice regarding HIV screening in hospitals and clinics, he adds.

"It's a long, incremental process going from guidelines to policy to implementation," he says.

Unlike many other chronic illnesses, HIV adherence must be extremely high for patients to maintain good health, Sosman notes.

"When adherence is not up to snuff then it will compromise treatment options over the long term," he explains. "While that can be true of other chronic conditions, it's very true and can happen very quickly in HIV."

One of the benefits of the HPTN 052 intervention and study was that it promoted ART adherence to couples, as opposed to focusing on the individual who is HIV-positive, Cohen notes.

"They have a collective goal of protecting the health of the HIV-positive partner," he explains. "It's very powerful and a very desirable strategy for this disease."

HIV adherence is challenging and will take a community's efforts.

"We want to empower the health system to allow folks to take their medications over decades," he adds.

"Although we have once-a-day regimens now, we have to look at things that would interfere with someone taking them over 20 years," he says. "It might not be nausea or diarrhea; it might be mental health issues, insurance issues, access to care, and all of these issues that can interfere with long-term adherence."

This is a different set of adherence issues than HIV clinicians experienced 10 years ago, he notes.

"We don't have patients take as many pills as many times a day with as many short-term side effects as we did 10 years ago," Sosman says. "But adherence issues still are potent."

Reference

  1. Sosman JM. Optimizing HIV care: policy implications. Am J Man Care. 2010;16(11):S339-S344.