HIV prevention pill records 100% success rate

Nigeria to begin study on pre-exposure prophylaxis in Nnewi, Calabar, Jos • NACA roundtable calls for nationwide introduction of novel drug

A new study has found that 100 per cent of participants taking Human Immuno-deficiency Virus (HIV)/Acquired Immune Deficiency Syndrome (AIDS) prevention pill remained infection free.

The study conducted at Kaiser Permanente in San Francisco, United States (U.S.) involved more than 600 high-risk individuals, most of whom were men who have sex with men. These individuals were healthy at the time of enrollment and were put on a daily regimen of a blue pill called Truvada as a pre-exposure prophylaxis (PrEP).

Lead author Jonathan Volk, a physician and epidemiologist at Kaiser Permanente San Francisco Medical Center, described the study as “the first to extend the understanding of the use of PrEP in a real-world setting and suggests that the treatment may prevent new HIV infections even in a high-risk setting.”

The U.S. Centers for Disease Control and Prevention (CDC) says that PrEP has been shown to reduce the risk of HIV infection by up to 92 percent when taken consistently but is much less effective when taken inconsistently. In one key study, called PROUD that included men who have sex with men in Britain, the risk was reduced by 86 percent.

In this study, 100 percent of the participants remained HIV-free. That’s right, not a single person in the study, published in Clinical Infectious Diseases, became infected while on the drug during the study period that included 2.5 years of observation.

“Tremendously good news,” University of California-San Francisco researchers Kimberly A. Koester and Robert M. Grant (one of Time’s most influential people of 2012 for his work in AIDS) said of the results in a commentary accompanying the publication of the study.

Not long after the Food and Drug Administration first approved the drug for preventive HIV use in 2012, the Los Angeles-based AIDS Healthcare Foundation derided it as a “party drug” and warned that high-risk individuals would use it instead of condoms — raising the risk of transmission of other sexually transmitted diseases. #Truvadawhore went viral. But as more studies have come out showing how well it appears to protect against HIV, many of those critics appear to be turning around.

Koester and Grant emphasized that despite the promising findings in the Kaiser study many questions still remain, a number of them practical in nature.

“What proportion of the population vulnerable to HIV will take a pill a day to prevent it? How will costs of the medication and clinic visits be paid for?” they asked. “Assuming people are willing to use PrEP and can access PrEP, will they take the medication as directed? Will uptake and use be higher or lower among those at higher risk? Will people place themselves at higher risk or HIV and sexually transmitted infections (STIs) as a consequence of using PrEP?”

The pair said it wasn’t clear from the study if the reported rate of sexually transmitted infections in the study is an increase or not and that further investigation is needed. They recommended that Truvada be combined with a parallel plan to prevent other Sexually Transmitted Infections (STIs), which may include the use of condoms, more frequent testing and discussions with prospective partners.

Meanwhile, Nigeria is in a process of commencing a study on PrEP and Treatment as Prevention (TasP).

Nigeria is going into the study through the National Agency for the Control of AIDS, NACA, because of its immense positive effects on the HIV/AIDS epidemic in the country.

Until now, multiple studies have established that anti-retroviral drugs could be used to reduce the rate of infection in a population in two different ways, known by the acronyms PrEP and TasP.

Pre-exposure prophylaxis, or PrEP, is a procedure for people who do not have HIV but who are at substantial risk of contracting the virus to prevent HIV infection by taking a pill every day. The pill (brand name Truvada), which contains two medicines (tenofovir and emtricitabine) were used in combination with other medicines to treat HIV. When someone is exposed to HIV through sex or injection drug use, these medicines can work to keep the virus from establishing a permanent infection.

Treatment as Prevention or TasP, on the other hand, targets people who are already infected with HIV-1, reducing their infectiousness in the population.

Multiple studies have established that, after about the first six months of treatment, anti-retroviral therapy (ART) reduces HIV-1 concentrations to undetectable levels in blood plasma and genital compartments. Additional studies have demonstrated that HIV transmission by an infected person is significantly reduced when that person adheres to ART well enough to maintain viral suppression.

Chief Communications Officer (NACA), Toyin Aderibigbe, said the study is not being done to determine whether PrEP works or not as it has long been established that PrEP actually works when used in combination with other methods of HIV prevention.

She said the study is however being carried out in Nigeria to see whether it will work in real life situations among the Nigerian population under normal conditions. The initial studies that showed that PrEP works were done under well-controlled situations.

Aderigbigbe further explained: “NACA and other key players that will participate in this study will collect relevant data that will tell us how these strategies will work in real life situations. Thus the study is expected to provide needed information on how to implement the strategies in a large population as part of a comprehensive public health program aimed at preventing HIV infection. The treatment strategy to be used in this project will adopt both TasP and PrEP.”

She said three sites have been selected for the study. “They are Nnewi in Anambra State, Calabar in Cross River State and Jos in Plateau State. Teams for the study that will work at various sites are being put in place,” Aderigbigbe said.

She said some of the questions that the study teams will be trying to answer include the following:

What are the barriers to uptake, that is, why would people hesitate to adopt a prevention strategy?

What are the barriers to adherence, that is, what would prevent a person who has started PrEP or ART from continuing it?

What are the most cost-effective ways of delivering, not just the drugs, but the counseling and support needed to make the strategies work? Should there be a separate program? Is it better done within an established programme?

Aderigbigbe added: “Sero-discordant couples are couples in which one partner is HIV positive while the other partner is HIV negative. ART, necessary for TasP, is not indicated for the infected partner until quite some time after initial diagnosis. So the study will provide an avenue for PrEP and TasP to work together for long-term prevention of HIV infection for a sero-discordant couples. Throughout this period, the uninfected partner is at elevated risk.

However, if PrEP is adopted by the uninfected partner when the infected partner is diagnosed, that risk is significantly reduced. Eventually the infected partner begins ART (TasP) and sometime later achieves viral suppression.

“At this point PrEP can be stopped because once the infected partner is suppressed (undetectable levels of the virus), the risk of transmission of HIV to the uninfected partner is significantly reduced.”

She said the project will have three primary goals:

•Construct a model that effectively delivers PrEP to serodiscordant couples. Within the context of this goal, the measure of effectiveness will be the number of new infections averted.

•Measure the cost effectiveness of the model. The measure of cost effectiveness will be cost per life-year gained and cost per infection averted

•Estimate what would be needed to scale up the delivery model to the national level.

“NACA understands that, given the data and experience to be gained from the project, it should be possible to present this to stakeholders for consideration as part of the policy and guidelines for the comprehensive combination prevention programme in the country,” she said.

Meanwhile, there are several dozen other ongoing clinical trials worldwide using Truvada in different populations. In South Africa, for instance, National Institutes of Health-funded researchers are looking at its use in heterosexual adolescent men and women ages 15 to 19 and in Australia the government is looking at people in relationships with HIV-negative partners. The issues they are hoping to find out more about include the factors that can influence an individual’s compliance with taking the pills regularly, how effective the pill can be when it’s not taken regularly but before and after sex, and how to integrate education about Truvada into regular clinic services.

A previous story stated that another study on Truvada found that the drug prevented infection in about 86 percent of participants. The study, called PROUD, lowered their risk by 86 percent.