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.

Thursday, June 30, 2011

Is the Big Pharma Tail Wagging the Dr Dog?

In addition to the good work that the Aids Healthcare Foundation is doing to question the 'fast-tracking' of the use of Truvada as PrEP when it has so far shown such poor efficacy, a group of 55 US physicians have signed a letter, also urging the US Food and Drug Administration (FDA) to delay approval until further tests, which may take years, have been carried out.

PrEP may be a great theory and Truvada may be a great drug. But there is little to get excited about yet. If effectiveness in the real world (as opposed to efficacy in carefully controlled trial contexts) can reach a reasonable level, which would be a lot higher than the unimpressive 44% found in the iPrEX study, then it will be time to consider the use of Truvada as PrEP.

It's good to hear that some doctors are standing up for their patients. Others appear to be in the thrall, or in the pocket, of Big Pharma. Many AIDS and human rights activists seem to have got the wrong end of the stick on this one: people have a right to safe healthcare, not to be used as free lab-rat material.


Saturday, June 25, 2011

Interest in PrEP Wanes with Accurate Information about Effectiveness

The Aids Healthcare Foundation is one of the few very influential institutions questioning the wisdom of rushing into widespread use of PrEP before we really know how well it will work, what challenges it may present and whether it is the best option for some, or even any, risk group.

Their survey is worth a look but a couple of the findings in particular caught my eye. Aside from the fact that most people think they are not at risk, even thought they are sexually active and engaging in anal sex, only 42% say they always use condoms. Saying they 'sometimes' (34%) use condoms is rather vague and may not differ from those who 'rarely' (9%) use them. And 15% say they never use them.

These figures for condom use contrast strongly with answers to the question about using condoms if taking PrEP as well. 83% say they would continue to use condoms if they knew that PrEP was only 90% effective. And only 63% said they would be 'very likely' to remember to take PrEP every day.

The need for regular health visits and other measures only reduce the percentage willing to take PrEP a bit but sharing costs puts a lot of people off. $720 a year results in 59% of people saying they wouldn't choose PrEP. The result is not much different when the cost sharing goes down to $400 per year.

But resistance and side effects are taken very seriously by these health conscious people, many of whom only sometimes use condoms when engaging in anal sex. A small risk of kidney damage or bone loss over a long period of time taking the drugs results in 66% saying they would not take it.

And for the possibility of resistance to certain antiretroviral drugs if the user becomes infected with HIV, which may be far more likely than the side effects mentioned, a whopping 71% say they would not take PrEP. Perhaps they are aware of the implications of resistance, one of which is that the cost of their treatment will rocket.

It's good that the Aids Healthcare Foundation are interested in probing the issue of PrEP, rather than joining in the wholly unwarranted jubilation. Perhaps HIV drug users and potential users are aware that resistance, which is so incredibly valuable to the drug industry, is a potential disaster for them.


Thursday, June 9, 2011

Can PrEP Be Used As and When People Need it or Must it Be Taken Daily?

So far, PrEP has only been approved for daily use, not for intermittent use. Intermittent use, if it works well, could be a lot cheaper than daily use. It could also be a lot easier to adhere to that way. The side effects of taking strong medication might be reduced. And perhaps resistance would develop more slowly with intermittent use. Who knows?

These aspects of intermittent use will be examined in the HPTN 067 ADAPT study (Alternate Dosing to Augment PrEP Tablet-taking). Of course, the retail price of PrEP will be higher if those eventually using it are only taking the drug when they need it, but individuals should need fewer doses. And the hope is that it will work out cheaper for them. The effect of the availability of PrEP will also be assessed for its effect on sexual risk taking.


Monday, June 6, 2011

Would People Take PrEP Every Day? How Much Would they Pay?

An article by Enrique Rivero discusses the reactions of some people to the concept of pre-exposure prophylaxis (PrEP), the use of HIV antiretroviral medication by HIV negative people to reduce the probability of becoming infected. So far, there has been little written about PrEP that is not industry driven hype.

A study carried out in Peru used consumer marketing techniques to gauge the attitudes of some members of 'high risk' groups there. Apparently cost was a lot more important to them than effectiveness. The amount they would be willing to pay would not be considered much in the minds of the pharmaceutical industry, whose greed is boundless.

But there's also a problem with expectations because people expected PrEP to be 100% effective. In trial conditions, PrEP was only found to be 44% effective, which doesn't bode well for its use outside of trial conditions. People also expressed a preference to use the pill intermittently, a use that has not yet been demonstrated. In the much hyped trial with the 44% effetiveness, participants were supposed to take it every day.

I'm not a big fan of such techniques but they do suggest that the issue of PrEP would be better dealt with through sober research and honest reporting than the infantile hype that we have seen so far.

Also, the lowest cost, which participants preferred, would still be far too high for most Africans in high HIV prevalence countries to afford. PrEP never looked like something intended for people in high prevalence countries but I guess those trying to hawk PrEP still hope that bucket loads of aid money will be spent on it. So they don't want to pitch a competitive price if there is no real need to compete.

The study doesn't show much that couldn't have been worked out beforehand and the methodology will probably cut little ice in the scientific community. Which is a pity, because they seem more interested in marketing PrEP than in genuinely assessing its potential to reduce HIV transmission.

The industry clout behind PrEP seems much too strong to let a few problems like those alluded to in this marketing study have any influence on the process of foisting it on an unsuspecting public. If the study posed any threat at all, it seems unlikely it would have seen the light of day. Or perhaps I'm just too cynical, altogether.


Wednesday, June 1, 2011

Another PrEP Trial Casts Doubt on Strategy's Effectiveness

A trial of Truvada as PrEP in Botswana, the TDF2 trial) has changed its course after it became clear that it would not be able to demonstrate effectiveness in reducing HIV infection. No doubt the reasons given for changing course are valid enough; low and declining HIV prevalence in the trial population, high dropout rate, pregnancies and lack of commitment to time requirements.

It's probably unsurprising that the world's media are not clamoring to cover yet another PrEP non-event, though this contrasts sharply with coverage of their one 'success'. However, the thirtieth anniversary of the 'first' AIDS case will be marked on June the 5th. Only good news will be sought when it comes to marvelling at how things have changed over the last 30 years.

For those who think that the whole AIDS industry has been hijacked by big business, especially Big Pharma, it's interesting to note an article from the 20th anniversary, June 2001:

"It's not the drug cocktails that are going to enable us to overcome this major, major social problem," says Dr. Fred Sai, Ghana's top AIDS expert. "It can only be done by education, preventive health measures and creating better living standards. I am afraid that the big U.N. conference on AIDS in June is going to get hijacked by this clamor for drugs, drugs, drugs, when the answer is prevention and building better societies."

In a sense, we have a come a long way, a long way towards getting more people on drugs and inflating the profits of Big Pharma. As for wiping out HIV, some may question our progress.