18 Jun 2010

Will a Pill a day keep HIV at bay?

Fridae’s Men's sexual health columnist Jan Wijngaarden discusses PrEP, PEP and iPrEP, and the extent to which anti-retroviral drugs for HIV can indeed help prevent HIV (but not STI) infection.

Sometimes we forget how important some things are in life, especially if we use them often. Take acetylsalicylic acid. Usually when I ask for it, people don't know what I am talking about, but it sounds impressive, nevertheless. Until I use its most common brand name: Aspirin. Acetylsalicylic acid was discovered in 1853 by the French scientist Charles F Gerhardt. One could say that this was the best French invention since the French kiss! It took a bit more effort by several other scientists before it became clear what it was that he had created. In 1897 scientists from the German firm Bayer discovered its pain-killing effects and as soon as 1899 Bayer was selling Aspirin around the world. After its patent expired (in 1918), other companies were also allowed to produce acetylsalicylic acid under their own brand-names. New pain-killers, based on other chemicals, followed soon: Paracetamol (1956) and Ibuprofen (1969).

Apparently, according to Wikipedia, the world defeats hangovers, converts unwilling sex-partners with headaches, and oh yes, also reduces the effects of fever, flu and pain using 40 million kilos of Aspirin per year! Imagine! While Aspirin lost a lot of market share to Paracetamol and Ibuprofen, its sales have recovered since the mid-1990s when it was found that acetylsalicylic acid can help PREVENT heart attacks and strokes. So many (mostly older people) use one pill a day to keep heart attacks away...

Interesting - taking a pill not to treat a disease, but to prevent it from occurring!

What do anti-retroviral (ARV) drugs do?

This brings me to the topic of this column. Many of you must have heard about the existence of medicines that can reduce the effects of HIV infection in those who are infected. These medicines can, in different ways, block HIV from reproducing in the human body. Usually people are prescribed three drugs at the same time, often combined in a single pill, sometimes called a 'cocktail' (sorry guys no alcohol in this one!). Each of the drugs in the cocktail works in a slightly different way, and together they are much more effective than each of the drugs by itself. The medicines can be so effective that (when they are duly taken according to the prescription) it becomes impossible to measure the amount of virus that an infected person has in his blood. This is good for the health of a person taking these drugs, and it probably also makes a person using these drugs much less infectious to others. The drugs I am talking about are called 'Anti-RetroViral Drugs' (ARV) and the process of treating HIV infection with a combination of ARV drugs is called Anti-Retroviral Treatment (ART).

The introduction of ARV drugs, and the increasing variety of slightly differing ARV drugs, allowing for changes in the treatment if a person becomes resistant to components of the cocktail, has led to big advances in the life expectancy of people living with HIV. The nasty side-effects of earlier medicines tend to be less in the newer generation of ARV drugs, although side effects remain. It is now believed that people who live in countries (or cities) where they have access to very good health care, the chance is high that they will survive their infection for several decennia, and end up dying of 'old age' rather than of AIDS. THIS IS WHY YOU SHOULD GET TESTED FOR HIV, if you haven't already done that for a while!

Coming back to the Aspirin example... Many people use Aspirin (or similar drugs) to reduce the chances of a stroke (or of a hangover – even though the effectiveness of this has not been proven). So how about I take ARV drugs before having unsafe sex – can that prevent HIV infection from happening?

That is, literally, the One Billion Dollar question. Just imagine: you take a pill, go out, meet someone and have fun without bothering about condoms! Drug companies would make billions in profits. (Maybe Hugo Chavez and other socialist leaders would even start mixing the drugs in the drinking water!).

Currently, in several countries around the world, research is being conducted to look at the extent to which ARV drugs for HIV can indeed help prevent HIV infection. The use of ARV drugs for this purpose is called 'Pre-Exposure Prophylaxis' (PrEP). This to distinguish it from 'Post-Exposure Prophylaxis' (PEP) – which is the use of ARV drugs AFTER possible exposure with HIV – most often this is used by medical personnel who have accidents with (potentially) infected blood during their work, or by people who were raped and possibly exposed to infected semen. PEP is also more and more often used by gay men who experienced condom breakage or just 'forgot' to use condoms, in the heat of the moment... By the way, if you think you could have been exposed to HIV, you have to start PEP as soon as possible, and not later than 72 hours after possible exposure. Usually you have to keep using the drugs for a period of four weeks. Since it is during the first months of using ARV drugs that the most severe side-effects usually occur, this is NOT a nice experience, I can promise you, and its actual effectiveness in preventing infection is still debated.

Preventing HIV infection by taking ARV pills BEFORE sex

So back to the topic: Preventing HIV infection by taking ARV pills BEFORE sex. Several research trials are looking at that at the moment. Put in simple terms, the research works as follows: a group of volunteers is recruited and randomly assigned to two groups. There is one group of people using ARV every day, and one group of similar people using a fake drug. The participants are 'blinded' – i.e. they do not know in which group they are. They are both counselled and told to be safe and use condoms (or, in the trials with injecting drug users, follow harm reduction principles). The scientists then look if the ARV-using group gets infected less rapidly than the latter.

This takes several years to follow up. So far there are no results from these trials. The problem with these trials is that they all focus on populations that have to take the ARV drug every day. Just like women who use the pill to prevent pregnancy. However, if the trials work, daily PrEP may not be a feasible option for most gay men. Because using these drugs daily is not pleasant in terms of side-effects. Also, the chance of forgetting to take it is always there – especially if you are on a normal work/study day and do not plan to have any sex. Indeed, the majority of gay men are not exposed to HIV on a daily basis and therefore probably do not need to take ARV drugs every day. Finally, while they have become much cheaper recently, ARV medication remains quite expensive for most gay men, particularly those in poor countries or settings.

Therefore, rather than only focusing on daily use, we should also have information about the effectiveness of using ARV drugs intermittently - in other words, not every day, but only on the days that we have sex. This proposed regimen is called iPrEP – which stands for 'Intermittent Pre-Exposure Prophylaxis'. The benefits would be obvious: no need to take daily pills; it would be more convenient and cheaper, and probably also better for your health.

Unfortunately currently there are no clinical trials evaluating the efficacy of iPrEP, even though this regimen has, according to available science (including results in test animals), the same biological plausibility of effectiveness as daily PrEP. It is not likely that such trials WILL be held. Because if the ongoing studies demonstrate that daily PrEP does indeed protect against HIV infection – which very likely will be the case – it will become difficult to evaluate the efficacy of iPrEP, because – for to ethical reasons – daily PrEP would need to be given as comparison drug to the volunteers in the fake-drug-group. 

Because the differences in effects between daily PrEP and iPrEP are likely to be very small, such a study would need more than 10,000 randomly assigned volunteers to prove whether iPrEP is as good as daily PrEP. It would take several years to conduct and would require enormous financial resources. Who would invest in this? Surely not the pharmaceutical industry, which is heavily invested in the ongoing daily PrEP trials... They want, after all, to sell drugs. Loads of them. Every day. 

This is a pity - because even if positive results are shown by the daily PrEP trials, probably in practice most gay men would be taking the pills intermittently anyway – because they can't afford daily pills, because they don't want daily pills or because they simply forget to take them every day. This is a complicated issue which has, unfortunately, hardly been taken up by gay activists. 

I would be interested to hear your views about this new potential, but still controversial HIV prevention technique. 

Would you be willing to take a pill every day if you could ditch condoms and be 100% sure it would prevent you from HIV infection (but not from other sexually transmitted infections)? And how about if you could be 70% sure? Or 50%? 

No easy answers here, I am afraid! 

PS: To pre-empt renewed hate-crimes against me from the Condom Mafia, let me repeat here, again and again, that I LOVE condoms, under all anal circumstances. They are much healthier for you than pills, as long as you don't swallow them! Also they prevent against many sexually transmitted infections – something ARV drugs do not.

Jan Wijngaarden has worked, in different functions and roles, on promoting HIV prevention, care and support for men who have sex with men (MSM) since 1994. He is also the moderator of MSM-Asia, an information network on MSM, HIV and human rights, with nearly 600 members from across the region. If you want to become a member of MSM-Asia, or for information requests or comments, pls contact him at jwdlvw@gmail.com