Pre-Exposure Prophylaxis or PrEP

Pre-exposure prophylaxis (PrEP) involves putting HIV negative people on antiretroviral drugs (ARV) with the aim of protecting them from HIV infection. This blog looks at some of the pros and cons of PrEP.

Saturday, July 21, 2012

PrEP is Win-Win for Big Pharma, Lose-Lose for Ordinary People

When a PrEP trial produces poor results, the reaction is often to point the finger at the patient: they didn't take the drugs regularly, 'adherence' was low, etc. The irony of this is that people thought of as good candidates for PrEP are often those who have not successfully modified their sexual behavior, or have shown themselves unwilling to do so. If they will not or can not modify their sexual behavior, why would they be more willing or able to modify their drug taking behavior?

Some drug trial reports parcel up the high achievers and exclude the low and medium achievers and call it a 'sub-study' or something similar. But the point of a randomized controlled trial is to make it clear what kind of result can be expected of people taking part, not what kind of result can be expected if everyone behaved as drug manufacturers would wish them to. Given that people don't behave in real life as they do during drug trials, the results for strategies such as PrEP so far have been somewhat encouraging, but not good enough to roll out the strategy.

Even with PrEP, people are encouraged to engage in safe sex, to limit their number of partners, to use condoms, etc. If they can't or won't do some or all of those things, PrEP will not be very effective; but it may not have any positive impact at all. Those behind the trials and those producing the drugs are anxious to portray the strategy as tested and proven, but it is most definitely not, not yet anyhow. One of the main exponents of the strategy tries to persuade us that PrEP is the way to go, but some of his readers are clearly not convinced. And the opposing case raises additional concerns about PrEP, referring to the strategy as 'grasping at straws'.

In countries where HIV prevalence is very high and transmission is highest among low (sexual) risk groups, those engaging in heterosexual sex with one HIV negative partner, PrEP is not going to be feasible. Those who face the lowest risk, but are paradoxically the highest risk group in Modes of Transmission Surveys, are unlikely to be targeted by a PrEP campaign.

And given that the majority of HIV positive people in need of treatment are still not receiving it due to cost, infrastructure, political and other reasons, it would be odd to offer the same drugs to people who are still HIV negative. It would seem far better to establish what exactly the risks are and address those risks before throwing yet more drugs at the problem. But PrEP is the way to go if you want to sell lots of drugs to healthy people; if that doesn't work, you'll then have lots of sick people to sell even more drugs to.