5 Things You Need to Know about the HIV Prevention Pill

 

It’s the little blue pill that could! TIME magazine’s “Top Medical Breakthrough” of 2010 was a study called iPrEx which showed that taking a pill a day, called Truvada®, can reduce the risk of contracting the virus by an average of 42% in men who have sex with men at risk for HIV. This approach, called pre-exposure prophylaxis (or PrEP), has the potential to be a promising new tool we can add to the HIV prevention tool box.

But the study raised as many questions as it answered. Now that the dust has settled a little, I want to probe a little deeper into the results and highlight some of the important points about what we do and don’t know about PrEP.

1. The pill is already available for HIV treatment and shouldn’t be used for prevention without a physician’s supervision

The pill that was used in the study is called Truvada® and is widely used to treat people living with HIV. It is one of many medication options to treat HIV and was chosen for the study in part because it is generally well-tolerated, can be taken once a day, and has few interactions with other medications.

But because it is already on the market, it means that people may use the drug in ways that are different than the reasons it was licensed. The pill is not a “morning after” pill and it’s not a “right before” pill either. It’s actually a fairly rigorous regimen that requires people take the pill consistently. Your doctor may prescribe it to you “off-label” for preventive use if you ask him or her, but the fact of the matter is we still don’t know yet if that’s a good idea for most people. The CDC (Centers for Disease Control and Prevention) is gathering together experts and community members to discuss whether this pill should be recommended for PrEP use for men who have sex with men and trans females. They may have a decision about their recommendation late 2011 or early 2012.

If a person does decide to use PrEP, it’s very important to be sure of the person’s HIV status prior to starting PrEP because in the study there were cases of drug resistance when people began Truvada® after they were already infected. It’s also important to be regularly tested for HIV and monitored by a physician for safety while taking PrEP.

2. The pill works (partially)

The study shows a 42% overall reduction of HIV infections when taking Truvada®. This number includes everyone who participated in the study even if people didn’t take the drug every day or hardly at all for that matter. How is that number calculated? The 42% reflects the difference in the number of infections between the people who were in the placebo arm vs. those who received Truvada®. Specifically, there were 83 men who acquired HIV in the placebo arm and 48 from the active arm; participants in the group that received Truvada® had 35 fewer HIV infections when compared with participants in the placebo arm.

Keep in mind this study shows that PrEP is only partially effective for men who have sex with men and trans females, and cannot be generalized to other populations. Studies are currently underway testing PrEP in other populations like injection drug users in Asia and serodiscordant couples (where one partner is HIV+ and the other is HIV-) in Africa. One study in high-risk women in Africa was stopped early because PrEP was not working to prevent HIV infection in that study.

3. The pill is expensive

Make that very expensive. At a cost of about $12,000 per year in the United States, one of the biggest questions yet to be answered is who will pay for it. This will be another major barrier that will prevent people from using the pill. There are discussions underway about whether or not insurance will pay for this. Stay tuned.

4. Currently it is recommended that PrEP be taken daily

As mentioned above, the study showed a 42% reduction in overall infections in the group that received Truvada®, in combination with a comprehensive package of prevention services. But they also did an analysis suggesting that participants who took the pill more consistently achieved a higher level of protection.

These results are encouraging and suggest that the pill works best if you take it consistently. Other dosing regimens have not yet been proven effective, but studies are underway to test intermittent dosing schedules. But is taking a pill every day to prevent HIV really going to happen? See my next point.

5. … but taking it every day is tough

In fact, some are arguing that if people can’t remember to use a condom every time, then how in the world will they remember to take a pill every day? My answer to that is I don’t think people are “forgetting” to use condoms. Condoms may not be accessible, people may be too drunk or high to be concerned about their safety, or it’s a conscious decision by one or both parties to not use a condom (because they believe they’re in a monogamous relationship, it feels better, etc.).

PrEP should not be thought of as a replacement for condoms but rather as a back-up plan of sorts. In the study, PrEP was provided in the context of comprehensive prevention services. Participants were given HIV risk reduction counseling and testing; free condoms; and regular monitoring and treatment for STDs. So there are still a lot of questions about how PrEP can be taken in real-life settings; and there are currently studies being planned to test just that.

Written by: David Nalos


References:

Grant, R.M., Lama, J.R., Anderson, P.L., McMahan, V., Liu, A.Y., Vargas, L., … Glidden, D.V. for the iPrex Study Team. (2010). Preexposure chemoprophylaxis for HIV prevention in men who have sex with men. New England Journal of Medicine, 363(27), 2587-99.

 
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