Drugs made by Gilead Sciences Inc. (GILD:US) that can prevent healthy adults from getting HIV didn’t reduce infections in African women because of lack of adherence to treatment, raising questions about the medicines’ usefulness in stopping the spread of AIDS.
About two thirds of women didn’t consistently use Gilead’s daily pill Truvada or Viread, which came in the form of a pill or vaginal gel, according to the study released yesterday at the Conference on Retroviruses and Opportunistic Infections in Atlanta. The women in the study said they were deterred from using the medicines because of stigma associated with AIDS drugs and side effects, which can include diarrhea and nightmares.
“Women were not using the product and those women least likely to use the product are the ones most at risk for HIV infection, they are young women and those who are not married,” said Jeanne Marrazzo, a researcher at University of Washington in Seattle who led the study.
The finding may cause global health officials to rethink their strategies for using the treatments as a form of prevention. U.S. regulators approved Gilead’s Truvada last year as the first drug to prevent HIV infection in healthy adults. Health organizations worldwide have been studying ways to get the pill to regions hardest hit by the epidemic and have called it a new tool in ending the epidemic.
In addition to being used as a form of pre-exposure prophylaxis, known as PrEP in the AIDS community, Truvada is a main treatment for people infected with AIDS and works by stopping the virus from taking hold and replicating in the body. It had more than $3 billion in sales last year.
Because of the irregular use, there was no significant difference in AIDS infection rates in the women taking the drugs compared to a placebo.
Some of the 5,000 women in the study, many who enrolled for the free health services, said they weren’t using the products because of the stigma associated with taking an AIDS medication, even with the knowledge that it was to prevent the disease, Marrazzo said. Others had issues with the side effects though those typically clear up over time, she said.
The findings “reinforce what we already know from previous trials -- these interventions work when they are used, and they don’t work when they are not used,” said Mitchell Warren, executive director of AVAC , a New York-based AIDS advocacy group. ”Now we have a dual responsibility to understand who might benefit from daily PrEP and ensure that they can access it, and to accelerate the development of additional options that can meet the urgent needs of others.”
In the study, women received either Gilead’s Viread as a pill or vaginal gel, the daily pill Truvada, which combines Viread with Gilead’s emtricitabine, or a placebo pill or gel. Most of the women were in South Africa with the remainder in Uganda and Zimbabwe.
About 6 percent of patients assigned to the Viread daily pill or vaginal gel group developed HIV and 4.7 percent in the Truvada group become infected. That compares to 6.8 percent who became infected using a placebo gel and 4.2 percent infection rate among the placebo pill group.
About half of the patients in the study had no traces of the drug in their system after the first four months, an indicator they had never regularly taken the medications. Those most likely to use the products were older women who were married, the ones at least risk for becoming infected with HIV, said Marrazzo.
“Given the low levels of adherence in the study, this result is not surprising: PrEP must be taken consistently to work effectively,” said Jonathan Mermin, director of the division of HIV/AIDS Prevention at the Centers for Disease Control and Prevention, in a statement. “Anyone considering using PrEP to help protect themselves from HIV infection should recognize that adherence to the daily regimen is critical.”
Past studies have found that Truvada can reduce the risk of HIV as much as 94 percent for people who take the pill regularly, according to a study cited by the U.S. Food and Drug Administration in May. In other trials, only 10 percent of participants took the medicine as prescribed, and one study was halted after no benefit was gained.
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