An interesting paper on HIV-1 prevention came out while I was on my Grand Adventure:
Preexposure Chemoprophylaxis for HIV Prevention in Men Who Have Sex with Men
Quick summary: They used an antiretroviral, Truvada, as a prophylactic drug. That is, you take this antiretroviral every day in the hopes of preventing infection as opposed to taking the drug to control infection.
Basically, its The Pill... for HIV-1 infection instead of pregnancy.
And it actually kinda worked!
People who took the drug as instructed, had a 92% lower chance of becoming infected than placebo.
YAY!
... Yeah, no, read that again: "People who took the drug as instructed".
Lots of people didnt take the drug properly, which is just asking for trouble, evolutionarily, and was a problem practically in that the overall lowered risk in the treatment group was only 44%, not 92%.
And then we have cost issues: One pill? $36. Yeah.
Gotta take it every day.
$13,140. Yeah.
And then theres the fact we already have an anti-HIV-1 prophylactic out there that works really well when used as instructed. Condoms reduce your chances of becoming HIV-1 infected at about 80-90%, and dont cost very much (freely available lots of places), nor do you have to remember to wear a condom every day. Just when you are having sex. And they dont have side-effects (unless youre allergic to latex). And then theres the fact that HIV-1 is not going to evolve resistance to condoms.
:-/
It would be better if this kind of prophylactic were available for women in high-HIV areas who are not in control of their sexual partners (aka, the wives of married men who are sleeping around and coming home and infecting their wife and subsequent children because they wont wear a condom), but at $36 a pop, thats not going to happen today. Or tomorrow.
At this point it just looks like an overly convoluted 'answer' to a problem we already have an answer to. And in a lot of situations, the old answer is the much better answer.
On 2 October, two dozen AIDS researchers gathered at the Eden Roc hotel on Millionaire's Row in Miami Beach, Florida, to learn whether an HIV prevention study they had just completed would become a millstone or a milestone for the field.
... Unlike the many HIV prevention trials that have failed or had positive but barely significant results, the study--called the Pre-Exposure Prophylaxis Initiative (iPrEx)--showed unequivocally that the treated group had 44% fewer infections after an average of 1.2 years. More encouraging still, most of the failure seemed to occur among those who did not take the pill as directed: A small substudy found that risk of infection plummeted by 92% in people who had measurable drug levels in their blood. The researchers applauded and some even cried when they heard the bottom line.
O.o... alright... okay... alright...
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I've had AIDS for 25 years now, and I have trouble keeping up with the regimen of pills on which my life supposedly depends. Imagine if you had to take a daily pill just just so you could have the occasional good time - and at that cost and not covered by insurance.
People won't stick with the regimin and they won't submit to the never ending counseling that goes along with PrEP - take your pill, take your pill, take your pill.
To take advantage of the publicity surrounding this PrEP craze, drug dealers at gay circuit (disco/sex) parties are selling a combo: Truvada, Viagra and a matching blue ecstasy cap for $60. a pop. It's a recipe for disaster.
I really like idea that any proposed prophylactic intervention *should* be held up against condoms, but, "they don't have side-effects (unless youre allergic to latex)" isn't exactly true. They do have one major side effect: the sex you're having is different from condom-free sex. Which is why studies like this can exist. The study population has condoms, they know how and why to use them, but they choose not to. This is also why, after a decade of widespread understanding of HIV transmission and decent sex education in Western Europe, folk are still not using them enough to reduce incidence rates. So we do (apparently) need something else: not just for the wives of KwaZulu-Nata, but also for the party boys of Zurich.
Having everyone constantly dosed up with NRTIs does sounds like a bit of a recipe for major, rapid resistance though.
This is, I think, the perfect use for something like this and a big part of why it is necessary. Much like the NRTI vaginal gel (actually wasn't that also Truvada based?) tested in Africa a few years back. In high risk HIV situations you need to be able to put the responsibility for preventing infections into the hands of the individual. Wives should not have to rely on marital fidelity to protect themselves. Women (or men for that matter) should not have to worry about conversion after rape. Whether this is the right method for that, or whether we will ever get the money to distribute it, is in question. But I think it is apparent that we severely need a method that doesn't rely on the goodness of men, because we have seen time and again that that doesn't fly.
That's going to be really pretty easy for girls who are expected to take oral birth control because their partners are shunting the responsibility for family planning off on them. Most of them seem to get by just fine. Or hey, what about the countless numbers of regimen compliant diabetics? And they have much more of a hassle. I have absolutely no sympathy for anyone who can't comply with a simple daily regimen. Especially if their lives and the lives of others depend on it. I do concede your point about cost though, insurance structure would need to change for this to become widely feasible.
Kind of true, kind of not. If I recall the studies correctly, the only escape mutants seen occurred in people who already had a pre-existing infection that their incoming screening didn't catch (why the hell we don't have sensitive enough screening might be another important question to ask). So at least the risk seems lower (although I will agree certainly present) when we are talking about the initial viral dose instead of an already entrenched and proliferating infection.
And/or because it's considerably more effective than condoms. And in some cases because their partners are idiots and take the girls' word for it that they're really taking the pills. But I digress.
You got a few things wrong, ERV - I work down the hall from these people so I know how the trials were carried out. The people recruited (all of them, the treatment and placebo arms) were put in a comprehensive AIDS prevention program including counseling and free condoms. So clearly, even though condoms are highly effective, people are people and don't use condoms all the time. When the study was being carried out, some of the noncompliant patients were asked the reasons why they weren't taking the drugs, and they answered that not knowing whether it was a placebo or not and not knowing whether it would be effective at all were the main reasons.
Tenofovir is already being put into clinical trials in women, and Gilead has licensed tenofovir to Indian/South African pharma companies where the yearly cost of treatment would be around $200 in 3rd world countries (still prohibitive for many, but not as bad as $13000).
Long time reader, first time commenter. It's $36 a pill at the moment, sold to a market of people who take it for HIV treatment. If that market quadrupled overnight - suddenly including HIV-negative users - Gilead could reduce the price enormously and still turn a huge profit. Just remember there is nothing natural about price.
Two methods is always better than one, too. That way if one fails there is a back-up (like women who use the pill and a condom).
This study proves Tenofovir works for prevention. I wonder if there are studies already underway for lower dosages?
I wonder if eventually we'll have a tenofovir (or whatever) implant/deposit medication. That could help vs noncompliance.
It's going to take a lot more evolutionary time for human physiology to evolve resistance to oral contraceptives (or for sperm to evolve a way to digest through latex...) than for a virus to evolve resistance to a drug taken relatively rarely.
Personally, I would love someone to create an oral contraceptive you could take just on the days you thought you would get some, not all the time, that didn't have the side effects of the morning-after pill.
Evolution of resistance requires an active or latent infection. The chance that a transmission strain of HIV has resistance to both efavirenz and tenofovir (sorry about before - tenofovir is only one of the components of Truvada) is nigh impossible. Hence, the people taking these drugs prophylactically will have to be monitored closely to ensure that they don't seroconvert.
But even in this trial, the infected patients displayed no resistance in isolated HIV strains. If you were taking one of the older post-exposure prophylaxis drugs, such as AZT, evolution of resistance would be a concern. But taking an nNRTI and NRTI combination pre-exposure prophylaxis, you would have to be noncompliant in a really bad way. That is, you would have to get infected, let the infection spread for weeks, and take your Truvada in sporadic intervals after that. Like weeks apart.
And really, the entire point of these trials is not to say that everyone in sub-Saharan Africa or Thailand or San Francisco has to take these drugs prophylactically. But identifying the epicenters and treating them could make a huge difference - especially given that the epicenters may not be able to request condom usage.