Approval of antiretroviral drug for HIV prevention brings us one step closer to ending the HIV epidemic

23 July 2012

Last week, a major milestone was reached when the US Food and Drug Administration (FDA) approved the antiretroviral (ART) drug, Truvada, to be given to sexually active, HIV-negative, high-risk individuals for use as a pre-exposure prophylaxis (PrEP), for preventing HIV infection. Truvada, a well-established oral medication that combines tenofovir disoproxil fumarate (TDF) and emtricitabine (FTC), which is better-known for the treatment of HIV-infected patients, is the first antiretroviral drug to be approved as PrEP.

The FDA’s approval arrives two years after the defining moment at the AIDS 2010 Vienna Conference, where results of the CAPRISA 004 tenofovir gel trial were announced, which provided proof–of-concept that antiretrovirals can prevent sexual transmission of HIV. The CAPRISA 004 trial showed that tenofovir gel, when used before and after sex, reduced the risk of HIV infection in women by 39% overall and created new hope for the fight against HIV/AIDS. Since then a series of clinical trials have shown that oral daily Tenofovir (TDF) or Truvada (TDF-FTC) can prevent HIV acquisition in several high-risk populations including women, men who have sex with men (MSM) and HIV-discordant couples.

Welcomed widely by policy makers, the research community and people living with HIV/AIDS, as well as many other HIV/AIDS stakeholders, the FDA’s backing of Truvada effectively paves the way for the drug to be prescribed to uninfected individuals in the United States who may engage in sexual activity that would place them at risk of becoming HIV infected.

This latest regulatory development has great significance in sub-Saharan Africa, the epicentre of the HIV epidemic, and where young women bear a disproportionate burden of the HIV epidemic. In the South African setting, approximately 5.6 million people are HIV infected. Research conducted in one rural district of South Africa has shown that the prevalence of HIV infection in young women increases dramatically from adolescence to young adulthood. At age 14, one in ten young female adolescents is HIV positive, but by the age of 25, her chances of being HIV-infected are one in two.

Why is it that young South African women are at such high risk of HIV infection? Despite the availability of a number of proven HIV prevention option including male and female condoms, safer sex education, medical male circumcision and ART treatment for HIV-infected individuals, young women are seldom able to persuade their partner(s) to use barrier protection, are unlikely to know of their partner’s HIV status and cannot be certain that her relationship is mutually monogamous: All these factors place her at high risk of HIV acquisition.

Professor Salim Abdool Karim, Director of the Centre for the AIDS Programme of Research in South Africa, a strong supporter of PrEP, has recently published in three prestigious scientific journals on this topic. His articles make a case for PrEP as an HIV prevention tool that enables vulnerable young African women in sub-Saharan Africa to take control of their HIV risk. In his correspondence to The Lancet, following the FDA’s advisory committee’s preliminary recommendation to approve PrEP, Professor Abdool Karim explained the challenge faced by young African women to protect themselves from HIV infection: “To rely on her HIV positive discordant male partner to come forward to test, to agree to take antiretroviral therapy, and to take his ART with high adherence, all for her protection, puts a woman’s risk of acquiring HIV back in the hands of men, thereby disempowering women and undermining their efforts to control their risk of HIV.”

The introduction of Truvada as PrEP is an encouraging development, as it signifies the translation of research findings into policy and programmes. The next challenge is to find ways of making sure that PrEP reaches those who are in need. Professor Abdool Karim contributes his opinion about the suitability for PrEP of two patient case vignettes (a 46 year old MSM and a South African female adolescent heterosexual) in the New England Journal of Medicine. He explains the clinical approach that he would adopt in assessing their HIV risk and explains why he would recommend PrEP in both instances.

The debate about PrEP has given rise to arguments that resource constrained countries and health systems, such as ours in South Africa, could not support the additional burden of providing PrEP to HIV negative individuals, and where, the view is held, that HIV infected communities should be prioritized for treatment.

Notwithstanding the potential challenges to health systems, Professor Abdool Karim’s editorial in Science appeals for a global response and commitment “to expand their support to address the current resource and health system constraints on the implementation of ART and prophylaxis in the worst AIDS-affected countries.”

The FDA’s announcement is well-timed, appearing just one week before the start of the 2012 AIDS Conference, which has adopted the slogan: Turning the Tide Together. Whether it is provided in an oral or topical formulation, PrEP, in combination with a comprehensive HIV prevention strategy that includes HIV counseling and testing, provision of condoms, medical male circumcision and treatment of HIV-infected individuals could bring us one step closer to ending the HIV/AIDS epidemic.