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.

Monday, February 28, 2011

Maximizing Profits from a Drug that Doesn't Work

Advocates of PrEP are probably as aware as anyone else that it hasn't yet shown much promise for men who have sex with men (MSM). It may not even be of much use in combination with other strategies (that also haven't shown much promise). But no one really wants to be the first to say that there is still a lot left to do, or admit that PrEP may end up in the broom cupboard.

Advocates still go back to their tack of 'sub-group analysis', taking the group that shows the best level of adherence to the drug and pointing out how effective it was for them. But high levels of adherence to PrEP could indicate other protective and risk avoidence practices, so care needs to be taken in interpreting this.

More importantly, levels of adherence in the group that shows the lowest levels of adherence could indicate that they engage in other risk behaviors and fail to take protective measures, adhering to PrEP just being one. Dr Joseph Sonnabend has discussed the folly of such analyses.

So these advocates of PrEP gathered around the ashes to figure out what to do and one of the questions they came up with was "what subset of men would be the most appropriate candidates for this new prevention tool?" Sonnabend's warning against sub-group analysis recommends an 'intention to treat analysis' as an alternative.

However, PrEP on an intention to treat basis would mean they would aim to put all MSM on the drugs. And then you have the problem that you will spend a lot of money for a miniscule return (if any). Even UNAIDS will start to notice if the effectiveness of PrEP doesn't improve considerably.

The group of advocates conclude that "PrEP is not a “magic bullet” and that it should not be viewed as the sole approach to reducing new HIV infections among MSM".

Exactly; they've also got a brand new roll of sticky tape, a stapler, a needle and some thread, a pot of glue and some thumb tacks, otherwise known as 'treatment 2.0'. So maybe they won't need the PrEP after all.


Saturday, February 19, 2011

Is Most HIV Spread By Sex? No, But Billions of Dollars Say Otherwise

Most of the billions of dollars currently being spent on HIV go to treating and caring for those already infected. A small amount is being spent on 'preventing' HIV but most of that is targeted at sexual transmission, despite the evidence that this is not the only type of transmission. It may not even be the most common type of transmission.

My remarks apply to African countries because that's where HIV epidemics are worst, where most HIV positive people live and where most people at risk of being infected live. It's where HIV, rather mysteriously, almost always spreads through heterosexual sex, while everywhere else in the world it mainly spreads through anal sex and injecting drug use.

One third of research and development funding for over 30 'neglected' diseases is spent on HIV, according to the G-Finder report by Policy Cures, an 'independent' group that happens to rub shoulders with some of the top HIV industry and pharmaceutical players. None of the money spent on HIV R&D is being spent on nosocomial or iatrogenic transmission, transmission that occurs as a result of unsafe medical treatment. HIV drugs, whether they are pre-exposure prophylaxis (PrEP), microbicides, vaccines or antiretrovirals, are aimed at sexual transmission.

In fact, HIV, TB and malaria R&D funding accounts for more than two thirds of all funding, amounting to over two billion dollars a year. Conditions that maim and kill millions of people every year, such as water-borne and food-born conditions, only receive a fraction of this amount. (Although it's interesting to note that the authors of the report are aware of the significance of diarrheal diseases.)

As for provision of clean water and sanitation which would reduce incidence of all of these conditions, this is not even discussed in polite circles.

Developing health services and facilities is not much discussed either. Pharmaceutical and other companies competing for billions of what is, after all, public money, know that if money was spent on health services and facilities and improving access to them, they would end up with far fewer customers.

So, there is no evidence that HIV is almost always transmitted sexually, even in African countries. But an awful lot of money is being spent on 'preventing' sexual HIV transmission while next to none is being spent on non-sexual transmission. And being able to talk about sex and promiscuity is quite a blessing for an otherwise sterile industry. So don't expect attitudes to change quickly.

[For more about nosocomial and iatrogenic HIV transmission, see my other blog, HIV in Kenya.]


Tuesday, February 8, 2011

Your Solution Is The Problem, Mr Gates

Bill Gates seems to write at least some of this own materials. His 'annual letter' reads as you'd expect it to read if written by someone who has little understanding, of and probably little interest in, development. His priorities are high profile issues and his 'solutions' are high technology and narrowly focused. But development issues and appropriate measures to improve conditions are not isolated phenomena, they also have a context.

Gates' grasp of public health is particularly weak. He seems to think that a handful of diseases can be eradicated, without any attempt being made to improve the conditions that result in those diseases remaining widespread, often after decades of work and billions of dollars spent. He wants to eradicate polio and prevent cholera, for example, without ensuring that people have access to clean water and sanitation.

An article in Science and Development Network picks up on Gates' comments about the 'slow pace of progress' in fighting AIDS. In the case of treatment and care for HIV positive people, he probably has a point, although he seems to think this area is doing well. Yet, in high prevalence countries, only a minority are receiving the care they need and most of them are lucky to receive drugs, which are of limited value on their own.

The pace of progress in HIV prevention is even more lamentable, but I don't really see Gates and his Foundation doing much about it. He seems to think that if drugs and a few other things rain down from the heavens, everything will be fine. He doesn't seem to see the need for health facilities, trained personnel, equipment, processes and other supplies.

This naivety might be touching in someone who is still growing into such a role as his. But given the extent to which he and his Foundation skew global health, development and spending priorities, treating his word as gospel is downright foolish.

The fact is, Mr Gates, most deaths among HIV positive people in developing countries are preventable and treatable. Most of the people who are dying should not be dying. They die because developing country health services can barely even dole out the antiretroviral drugs they are given in such huge quantities (sometimes), while they don't have the cheap drugs they need to stop people from dying from diseases the Gates Foundation doesn't consider worth bothering about.

But Gates still reverts to his obsession, drugs, in the form of vaginal microbicides and PrEP. We've tried forcing drugs down the throats of HIV positive people, lets now try to force them down the throats of HIV negative people as well. Oh, and he wants a vaccine as well. And male circumcision.

Money is not going into investigating how people are becoming infected with HIV. It's assumed that sex is the problem and drugs are the solution. Health systems just don't seem sexy enough to merit attention, nor do improved infrastructures, water and sanitation, basic education or anything else that might alleviate the conditions that allow HIV to spread rapidly.

Gates said "given all the lives that are at stake, I am willing to be viewed as a troublemaker by people who are happy with the status quo". Sorry, Mr Gates, but you are the status quo in development, Indeed, that's what makes you a troublemaker.


Sunday, February 6, 2011

In Case of Poor Health, Treat for HIV

Dr Joseph Sonnabend has a fascinating article on his blog about the original AZT trials, which notes that in the 1980s, many people with AIDS were dying of pneumocystis pneumonia, a preventable and treatable condition. That was in the US and other wealthy countries. But I suspect similar things are still happening in developing countries.

For example, sixty percent of people living with HIV in India are said to be dying of TB, a disease for which there are ample tests and drugs available. Dr Sonnabend notes a defeatist attitude in the 1980s but I don't think that attitude has lessened in resource poor countries.

In some countries, mothers are routinely treated with antiretroviral drugs to prevent transmission to their babies. But the health of the mothers themselves if often seen as being of little value compared to the life of  their babies.

HIV positive mothers who give birth to HIV negative babies are not likely to be seen as a priority and may become sick and even die from preventable and curable illnesses. And if mothers die, the chances of their children suffering ill health and even of dying are significantly raised. Prioritizing the needs of their babies and ignoring the longer term needs of their mothers is extremely short sighted and even self-defeating.

In Kenya, I met a number of HIV positive people who subsequently died from TB or from undiagnosed conditions. AIDS was always blamed, but the people who died were usually on antiretroviral medication. Just because they were HIV positive, it was assumed that they were going to die and when they became very ill, there was often little available to them that they could afford.

Many of them had TB, which was sometimes being treated. But even people with TB are assumed to be HIV positive, although only about half the Kenyans with TB are also HIV positive. There is little said about the massive TB epidemic raging in Kenya, unless insofar as it is associated with HIV. But it's a very easily transmitted disease and it appears to spread independently of HIV just as efficiently as in conjunction with it.

The article about India continues: "though we have 12,500 microscopy centers available across India, deaths occur mainly due to late diagnosis, owing to technology limitations". In Kenya, the problem may be due to factors other than late diagnosis, for example, lack of facilities for diagnosis, lack of access to health facilities and lack of drugs for even very common conditions.

Distribution of HIV technologies always seems to have a lot more to do with markets than about need. And when all you have is a hammer, everything looks like a nail. There seems little point in treating people with expensive antiretroviral drugs and allowing recipients to suffer from and die from preventable and treatable conditions. But who am I to tell drug manufacturers how to maximize their profits?

[For more about HIV and health care, see my other blog, HIV in Kenya.]


Wednesday, February 2, 2011

If You Need PrEP, You Probably Won't Receive It

Although not yet approved for use as a pre-exposure prophylaxis for men who have sex with men, CDC has issued guidelines for its use, a sort of de facto approval. But the guidelines make it clear that this is an expensive drug, intended for recreational use among those who can afford it. It's certainly not for people who live in the handful of African countries where HIV prevalence rates are the highest in the world.

For example, confirming that someone is at "substantial, ongoing, high risk for acquiring HIV infection" is going to be a bit of a challenge for the UNAIDS dominated prevention strategies in developing countries. As far as they are concerned, if someone is African and has sex, they are at high risk. The majority of infections occur among those engaging in what is essentially low risk sex. The contradiction doesn't bother UNAIDS.

Regular testing for those on PrEP is out of the question for most people in countries where most people are never tested and HIV positive people usually find out their status by the time their problem is AIDS rather than HIV. Similar remarks apply to regular sexually transmitted infection testing; poor countries don't have the health infrastructure to do this sort of work on large sectors of the population, even if they could identify which sectors those happen to be.

And so on. The measures recommended by CDC are pie in the sky for developing countries, where HIV prevalence wouldn't be nearly as high if they had such strong health services. And as for the remarks about adherence, the trial results cited completely fudge this issue. The overall 44% lower likelihood of acquiring HIV is constantly qualified by the higher figure achieved by those with high levels of adherence.

How about the lower figure for those who achieved the lowest level of adherence? People who fail to adhere to drug regimes or other measures that are intended to reduce risk of contracting HIV and other diseases are the very people who are at the highest risk. In other words, those least likely to adhere, and therefore to benefit from Truvada PrEP, are the ones who should be targeted. That's according to the guidelines, anyhow.

African populations are handy for testing out HIV drugs because there are very high levels of HIV transmission in many areas. But this drug is not intended for them. It is intended for those who wish to continue having risky sex but to minimize the risk of contracting HIV. The less risk they take, the better Truvada will work, but the less they will need it. The more risk they take, the worse Truvada will work and the more they will need it.