Dr. Vy Chu:
Hey everyone! By now you may have heard about the new study published yesterday in the New England Journal of Medicine about an HIV prevention strategy called "pre-exposure prophylaxis," or PrEP. Here's a link to the NYTimes article about it.
This post will be dedicated to explaining why this is an exciting development, how it might compliment or enhance the HIV prevention strategies we are using today, and who the study affects most directly. The conclusion might surprise you.
Hopefully, by now you already know about POST-exposure prophylaxis (PEP), whereby someone who is worried about a high-risk sexual encounter can start a triple-drug antiretroviral regimen within 72 hours of the exposure in order to decrease their risk of being infected with HIV. But what you may not know is that the guidelines on PEP were largely formulated based on a small 1997 study that looked at HIV prevention in a very different group (hospital workers who had a workplace exposure such as a needle stick) and who were given only one older medication (AZT). So a lot of leaps of faith had to be made in order to justify modern PEP guidelines.
Today's study was exciting for a couple reasons. For one, it was a pretty big study, and formulated specifically to study the effectiveness of using HIV treatment as a form of HIV prevention in gay men. Second, the researchers took the concept a step further by using PRE-exposure prophylaxis: having the medications already in the bloodstream when HIV exposure occurred. They followed two groups: one group took Truvada (a relatively safe and lower-side-effect HIV combination of two drugs) every day, and the other took a placebo. Both groups were tested regularly and received HIV prevention counseling as part of the study, and both groups were followed for up to two years. The final reason for excitement was the result:
The study found that the group taking Truvada had 44% less HIV infections compared to those who received a placebo. What's even more interesting is, when you examine the Truvada group closely - the people who had higher blood levels of Truvada during the study (and thus were likely taking it religiously every day) had even greater benefit - they were 92% less likely to be infected. So this is a big deal!
But, let's make sure we're excited for the right reasons. Remember that ALL participants in the study received pretty intensive (every four weeks) HIV prevention counseling, and were counseled and reminded to use condoms as the main form of HIV prevention. So these patients were practicing safe sex at rates higher than the general gay population.
My main point here: this study DID NOT compare the effectiveness of Truvada to condom use. In other words, this study by no means is saying that Truvada has any business being the primary HIV prevention strategy for anyone. And it shouldn't be, for a lot of reasons. Remember that there are a lot of STDs out there besides HIV, and only some are curable. Also, Truvada costs about $14,000 dollars a year to take - even people with very good insurance will pay really high copays monthly. And, as far as we know, you need to take this medication every day in order to get the maximum protective benefits. Add in the side effects and possible longterm health effects of taking this drug, and you really start to wonder: who exactly should be taking PrEP?
My thoughts are that this is a very useful and exciting study, but for a pretty limited group, at least in the short term, before more follow-up studies are done. I would say that the best candidates for daily Truvada PrEP are HIV negative gay men who are in relationships with an HIV positive partner. It would afford an enhancement of protection to those individuals, in addition to the safe sex and risk-navigation strategies they are already using.
But the study is worth a conversation with your doctor if you feel this study would apply to you. I've already fielded a few calls and emails from patients wondering if they should be considering Truvada. In general, my answer is: probably not. But having a conversation about HIV risk and prevention is always a good thing to have. Have a visit with your doctor if you have questions. If you don't have a doctor, we here at Capitol Hill Medical are ready to serve - just give us a ring!
-VY CHU, MD
Dr. Rob Killian adds:
Wow - way to go, Dr. Chu, for making the science understandable and for sharing with our community a truly gay physician's perspective. This is such great news and gives us hope that we can work together as patients and doctors to prevent even more HIV transmission in many of our couples and others who are at increased risk. I would second his advice, make this a topic of discussion with your doctor. Understand the risks, the costs and the potential benefits if you feel you would consider yourself a candidate of this prevention approach.