On-Demand Preexposure Prophylaxis Effective Against HIV

Marcia Frellick

December 01, 2015

Using a combination of tenofovir disoproxil fumarate (TDF) and emtricitabine (FTC) before and after sex was 86% more effective than placebo in protecting men having unprotected anal sex with men against HIV-1 infection, according to new results published in the December 3 issue of New England Journal of Medicine.

"While we wait for an effective vaccine against HIV, the use of such preexposure prophylaxis with TDF-FTC among high-risk men could contribute to a reduced incidence of HIV infection," Jean-Michel Molina, MD, from the Department of Infectious Diseases, Hôpital Saint-Louis, Assistance Publique Hôpitaux de Paris in France, and Université de Paris in France, and colleagues write.

The results of the multicenter trial, known as Intervention Preventive de L'Exposition aux Risques Pour Les Gays (IPERGAY), were published online December 1 to coincide with World AIDS day.

Dr Molina and colleagues hypothesized that rate of adherence, and thus efficacy, might be higher among high-risk men with an on-demand pill than a daily regimen, which had shown mixed results in previous studies.

The researchers randomly assigned 400 men who did not have HIV either to the TDF-FTC group (199) or to receive placebo (201) in a double-blinded fashion. A total of 16 HIV-1 infections occurred during the 9-month follow-up: two in the TDF-FTC group (incidence, 0.91 per 100 person-years) and 14 in the placebo group (incidence, 6.60 per 100 person-years), for a relative reduction in the intervention group of 86% (95% confidence interval, 40% - 98%; P = .002). Participants took a median 15 pills of TDF-FTC or placebo per month.

However, the treatment was associated with increased rates of serious gastrointestinal and renal adverse events compared with placebo: 14% vs 5% (P = .002), and 18% vs 10% (P = .03), respectively.

Results Join Landmark Achievements

 
The science has spoken. There can now be no excuse for inaction.
 

In a perspective piece, published in the same issue of the journal, Anthony Fauci, MD, director of the National Institute of Allergy and Infectious Diseases (NIAID), and Hilary Marston, MD, MPH, Medical Officer and Policy Adviser for Global Health for NIAID, write that the IPERGAY results join other significant achievements that have greatly improved HIV prevention and treatment over the course of the 2 decades since combination antiretroviral therapies were introduced.

As previously reported by Medscape Medical News, major questions have been answered by other landmark trials as to best treatments and when to start antiretroviral therapy.

"Taken together, these studies provide an evidence-based blueprint for effective treatment and prevention of HIV infection and will serve as critical tools in the fight to end the HIV-AIDS pandemic," Dr Fauci and Dr Marston write. "However, in order to realize that promise, the political will must be mobilized to match the scientific evidence and provide the financial and human resources necessary to dramatically scale up the HIV testing and treatment around the world. The science has spoken. There can now be no excuse for inaction."

Progress Is Mixed

In an accompanying article by Thomas Frieden, MD, MPH, director of the Centers for Disease Control and Prevention, and colleagues, the authors add that achievements in drug development and approval for prevention and treatment have empowered patients and communities, but there is much more work to be done.

Reporting has improved: as of 2014, the 42 states (plus the District of Columbia) in which about 90% of HIV-infected people are thought to live require that all CD4+ counts and results of viral-load testing be reported to the health department.

And the rate of new infections appears to be declining, although more people are living with HIV infection. In 2012, 1.2 million people in the United States were living with HIV infection, the authors note, which is up 20% from the previous decade. This is attributable to continued new infections and a 36.5% decrease in AIDS-related deaths from the previous decade.

However, between 2003 and 2014, diagnoses increased by 5% for men who have sex with men, the population in which two thirds of new infections now occur. Unprotected anal sex has become more common for gay and bisexual men, and blacks continue to account for nearly half of all diagnoses each year, mostly in this high-risk population.

Partner notification, testing, and linkage to services are still the exception rather than the rule, Dr Frieden and colleagues say, and represent a substantial area for improvement.

"The challenge now is to increase integration of health care and public health efforts in order to use these new tools to greatly reduce new infections," they write.

The study was funded by the National Agency of Research on AIDS and Viral Hepatitis and others. Coauthors of the study report receiving personal fees from Gilead and AbbVie; grants and nonfinancial support from ViiV Healthcare, Merck, Sharp & Dohme, Bristol-Myers Squibb, and Janssen; grant support from the National Agency of Research on AIDS and Viral Hepatitis, the Fondation de la Recherche Medicale, the FP7 through the MRC in University College London, the Banque Publique de Investissement, and Fonds Pierre Berge/Sidaction and the Canadian HIV Trials. One coauthor reports a pending patent related to anti-3S antibodies and a pending patent related to HIV disease progression and IP10 levels.

N Engl J Med. Published online December 1, 2015.

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