The HPTN 052 trial, which found that treating HIV positive people with antiretrovirals reduces transmission to their sexual partner by '96%', has been reported far and wide. That's great, up to a point. It means that HIV positive people can benefit from early treatment, another finding of the trial. But more importantly, it means that HIV positive people's HIV negative partner can enjoy a very high degree for protection.
What the reporting does not point out is that, while HIV positive people's partners are protected, not everyone is infected by their partner. The HIV positive people in discordant couples, themselves, were probably not infected by their partner. The might have been, but it's more likely that they were in a position where they would not have been protected by the sort of program suggested by the results of the HPTN 052 trial.
In fact, a very high percentage of new HIV transmissions in countries such as Uganda are estimated to occur in long term, monogamous couples, perhaps over 40%. But only some of these new infections occur within the couple. How do people think discordancy occurs in the first place?
What this means is that, once someone is infected, their partner (or even future partners) can be protected. So treating everyone in a discordant relationship will protect partners not already infected. But HIV prevention needs to go beyond targeting those who are already infected if they are to protect those who are not yet infected.
The theory is that everyone (or about 80%, even) in a population is to be tested for HIV regularly and anyone found to be HIV positive can be put on treatment straight away, instead of waiting, as is done currently. It is even claimed that it is possible to test everyone every year, and this may be true. But no one has demonstrated that yet, certainly not the HPTN trials.
So far, the majority of people in high HIV prevalence countries have never been tested for HIV and the majority of those who have tested have only done so once. Testing programs might one day be scaled up and testing may become something people do every year, like paying their taxes. Or it may not. And the so called 'test and treat', 'treatment as prevention', 'treatment is prevention', whatever it is called strategy requires regular testing for everyone, or at least a sizeable majority.
All the necessary elements may one day be achieved, but it is premature, and irresponsible to claim that "we now have the tools that could end the HIV pandemic" or that "HIV is 100 percent preventable", or, indeed, that "treatment is prevention". Treatment is, and has been for some time, part of prevention. But we can't eradicate HIV simply by throwing unlimited quantities of drugs at the disease.
[There's more about Treatment as Prevention on my other blog, HIV in Kenya.]
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.
Friday, May 20, 2011
Friday, April 22, 2011
Truvada and Tenofovir PrEP Trials Continue in Kenya Despite Setbacks
There are still PrEP trials going on in Kenya, this time among 4,800 discordant couples in the Thika area. The work is partly funded by the Gates Foundation, which is not surprising. But one of the findings in the shelved FEM-PrEP trial was that more women on the drug became pregnant than those on the placebo, despite all women taking some kind of contraceptive as a condition of the trial.
Increased fertility will not please either FHI, the institution running the FEM-PrEP trial, not the Gates Foundation, as both are firm believers in the assumption that development is a matter of population control, something that used to be called 'eugenics'.
Although antiretroviral (ARV) industry front group AVAC are trying to paint a rosy picture of PrEP, FEM-PrEP wasn't the first disaster. The iPrEx trial results were far too poor to allow further trials to proceed without extreme caution. Despite that, some groups are calling for approval of the use of Truvada as PrEP to be fast-tracked by the US Food and Drug Administration (FDA).
[For more about HIV and development, see my other blog.]
Increased fertility will not please either FHI, the institution running the FEM-PrEP trial, not the Gates Foundation, as both are firm believers in the assumption that development is a matter of population control, something that used to be called 'eugenics'.
Although antiretroviral (ARV) industry front group AVAC are trying to paint a rosy picture of PrEP, FEM-PrEP wasn't the first disaster. The iPrEx trial results were far too poor to allow further trials to proceed without extreme caution. Despite that, some groups are calling for approval of the use of Truvada as PrEP to be fast-tracked by the US Food and Drug Administration (FDA).
[For more about HIV and development, see my other blog.]
Labels:
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behavioral paradigm,
CAPRISA 004,
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FEM-PrEP,
iatrogenic Truvada,
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pre-exposure prophylaxis,
prepwatch,
recreational drugs,
technical solutions,
tenofovir,
unaids
Tuesday, April 19, 2011
AIDS Healthcare Foundation Are Right to be Cautious
The AIDS Healthcare Foundation (AHF) are a good friend to Western gays but Western men who have sex with men (MSM) seem to think otherwise. Gilead's Truvada, was found to be 44% effective in preventing HIV transmission in MSM in the iPrEx trials. This result means that the drug would be of marginal benefit, at best, outside of trial conditions. At worst, HIV transmission rates could stay the same or increase.
All AHF are saying is that FDA (US Food and Drug Administration) approval for use of Truvada as pre-exposure prophylaxis should be delayed until it is fully understood why effectiveness is so low and what sort of value this use of the drug has, if any. Do Western MSM wish to be guinea pigs in what would merely be a re-run of the trials but under less favorable conditions?
The FEM-PrEP trial of Truvada as pre-exposure prophylaxis for women engaging in (presumably vaginal) sex with men showed no effectiveness whatsoever in reducing HIV transmission. Most of the study participants were women in African countries, and perhaps Western MSM are not so worried about this group. But AHF are drawing attention to the fact that it is far too early to give the drug approval. They are not saying it should never get approval.
In areas where HIV transmission is phenomenally high, such as in the study areas, entire sectors of the female population are being infected. And even after these supposedly controlled trials, research doesn't appear to have shown why women are being infected in such large numbers, especially when their sexual behavior is similar to that of women in low prevalence countries and the men they are having sex with are far less likely to be infected.
If you don't know how people are being infected, throwing drugs at them will not solve the problem. Gilead may be able to increase their profits by a billion or more, but the HIV industry wasn't established to make wealthy and powerful pharmaceutical companies wealthier and more powerful. If and when PrEP is able to show its value in reducing HIV infection, it should be considered for approval. But it has not yet shown its value and the HIV industry should distinguish between who is suffering from the effects of AIDS and who is profiting from it.
[For further comments about PrEP, see my other blog.]
All AHF are saying is that FDA (US Food and Drug Administration) approval for use of Truvada as pre-exposure prophylaxis should be delayed until it is fully understood why effectiveness is so low and what sort of value this use of the drug has, if any. Do Western MSM wish to be guinea pigs in what would merely be a re-run of the trials but under less favorable conditions?
The FEM-PrEP trial of Truvada as pre-exposure prophylaxis for women engaging in (presumably vaginal) sex with men showed no effectiveness whatsoever in reducing HIV transmission. Most of the study participants were women in African countries, and perhaps Western MSM are not so worried about this group. But AHF are drawing attention to the fact that it is far too early to give the drug approval. They are not saying it should never get approval.
In areas where HIV transmission is phenomenally high, such as in the study areas, entire sectors of the female population are being infected. And even after these supposedly controlled trials, research doesn't appear to have shown why women are being infected in such large numbers, especially when their sexual behavior is similar to that of women in low prevalence countries and the men they are having sex with are far less likely to be infected.
If you don't know how people are being infected, throwing drugs at them will not solve the problem. Gilead may be able to increase their profits by a billion or more, but the HIV industry wasn't established to make wealthy and powerful pharmaceutical companies wealthier and more powerful. If and when PrEP is able to show its value in reducing HIV infection, it should be considered for approval. But it has not yet shown its value and the HIV industry should distinguish between who is suffering from the effects of AIDS and who is profiting from it.
[For further comments about PrEP, see my other blog.]
Labels:
AVAC,
behavioral paradigm,
CAPRISA 004,
FEM-PrEP,
iatrogenic transmission,
iPrEx,
nosocomial infection,
pre-exposure prophylaxis,
prepwatch,
recreational drugs,
technical solutions,
unaids
Monday, April 18, 2011
Unbelieveably High Adherence Doesn't Guarantee Effectivenss of Truvada
A less well publicized trial of Truvada for pre-exposure prophylaxis has finished early. Not only is it less well publicized, but the results are not being released in full until further notice.
Family Health International's (FHI) press release said "the Independent Data Monitoring Committee (IDMC) advised that the FEM-PrEP study will be highly unlikely to be able to demonstrate the effectiveness of Truvada in preventing HIV infection in the study population."
This trial was like the iPrEx study except that it was testing the use of Truvada to prevent HIV infection in women. The release of preliminary data only contrasts strongly with the way iPrEx data was released, even though the latter data was not particularly impressive.
Adherence appears to have been extremely high, higher than in the iPrEx study. But the rate of new infections was very high, at 5% per year, and there was not difference in rate between those on Truvada and those on a placebo.
Interestingly, 66% of women were using injectible contraceptives. This a popular contraception method in many African countries. Unsafe injection rates, which are extremely high in developing countries, might explain at least some of the transmissions.
Higher pregnancy rates were found among women who were taking Truvada and this was quite unexpected. It's good to hear that researchers and other commentators are being cautious, unlike with the iPrEx trial results.
Family Health International's (FHI) press release said "the Independent Data Monitoring Committee (IDMC) advised that the FEM-PrEP study will be highly unlikely to be able to demonstrate the effectiveness of Truvada in preventing HIV infection in the study population."
This trial was like the iPrEx study except that it was testing the use of Truvada to prevent HIV infection in women. The release of preliminary data only contrasts strongly with the way iPrEx data was released, even though the latter data was not particularly impressive.
Adherence appears to have been extremely high, higher than in the iPrEx study. But the rate of new infections was very high, at 5% per year, and there was not difference in rate between those on Truvada and those on a placebo.
Interestingly, 66% of women were using injectible contraceptives. This a popular contraception method in many African countries. Unsafe injection rates, which are extremely high in developing countries, might explain at least some of the transmissions.
Higher pregnancy rates were found among women who were taking Truvada and this was quite unexpected. It's good to hear that researchers and other commentators are being cautious, unlike with the iPrEx trial results.
Wednesday, April 13, 2011
PrEP Should Never Be First Line of Defence Against HIV
There's an interesting exchange that I heard about through JournalWatch. Readers of HIV/AIDS Clinical Care journal were asked if they would prescribe PrEP for a high-risk patient. Remarkably, 45% said they would not. More surprisingly, 35% said they would prescribe PrEP intermittently, surprising because this is not a currently recommended use. Only 20% said they would prescribe daily PrEP, the only use that is currently available.
But two detailed responses outline what the practitioner would do, step by step. And it is these steps that makes me wonder what form PrEP prescription would take in developing countries, where most people are unlikely ever to see a doctor.
Those with only vague notions of what PrEP is, anyone who has been informed by following the mainstream press, might think it is a pill that you can take to prevent yourself from being infected with HIV. In fact, it's a pill that may play some small part in reducing the probability of infection if you also take other precautions, such as always wearing a condom, reducing your number of partners, etc.
As one of the practitioners says, PrEP "should never be the first line of defense against HIV infection". The same practitioner says "the healthcare system [in the US] currently lacks the infrastructure to support PrEP care in the manner recommended by the CDC". Whatever Western health infrastructures lack, they sure as hell will not be found in developing countries.
But there is a sort of paradox about behavioral interventions that aim to reduce HIV transmission: PrEP depends on strict adherence, which is a behavioral matter. Whether someone is considered to be at high or low risk of HIV infection is based on their behavior. If their behavior is tractable, their risk can be reduced. If their behavior is not tractable, their risk can not be reduced.
So, if someone is the sort of person who would adhere strictly to a PrEP prescription, they would be likely to benefit from PrEP. But then they would be unlikely to be at high risk of infection. But then a person would be unlikely to be able to benefit from PrEP if they are genuinely at high risk of infection because of their behavior.
Perhaps a partner of someone whose sexual behavior puts them at high risk of HIV infection could benefit. They would need to take other precautions aside from PrEP, otherwise it is unlikely to give them much protection. But penile-vaginal sex is not particularly high risk, so PrEP is unlikely to be the intervention of choice anyway.
But two detailed responses outline what the practitioner would do, step by step. And it is these steps that makes me wonder what form PrEP prescription would take in developing countries, where most people are unlikely ever to see a doctor.
Those with only vague notions of what PrEP is, anyone who has been informed by following the mainstream press, might think it is a pill that you can take to prevent yourself from being infected with HIV. In fact, it's a pill that may play some small part in reducing the probability of infection if you also take other precautions, such as always wearing a condom, reducing your number of partners, etc.
As one of the practitioners says, PrEP "should never be the first line of defense against HIV infection". The same practitioner says "the healthcare system [in the US] currently lacks the infrastructure to support PrEP care in the manner recommended by the CDC". Whatever Western health infrastructures lack, they sure as hell will not be found in developing countries.
But there is a sort of paradox about behavioral interventions that aim to reduce HIV transmission: PrEP depends on strict adherence, which is a behavioral matter. Whether someone is considered to be at high or low risk of HIV infection is based on their behavior. If their behavior is tractable, their risk can be reduced. If their behavior is not tractable, their risk can not be reduced.
So, if someone is the sort of person who would adhere strictly to a PrEP prescription, they would be likely to benefit from PrEP. But then they would be unlikely to be at high risk of infection. But then a person would be unlikely to be able to benefit from PrEP if they are genuinely at high risk of infection because of their behavior.
Perhaps a partner of someone whose sexual behavior puts them at high risk of HIV infection could benefit. They would need to take other precautions aside from PrEP, otherwise it is unlikely to give them much protection. But penile-vaginal sex is not particularly high risk, so PrEP is unlikely to be the intervention of choice anyway.
Thursday, April 7, 2011
Will Profits From the HIV Pandemic Ever Be Accompanied By Progress?
The answer to the question 'will Africans most in need of PrEP be able to access it?' is not a straightforward yes or no. If the question were 'will Africans in need of the most common and effective drugs for the most common, treatable, preventable and deadly diseases have access to them?', the answer is 'they certainly don't have access right now'. So why should we believe they will ever have access to PrEP?
But the question is harder to answer than that. Even if the HIV industry were to wave a magic wand and grant PrEP to whoever needed it most, they have no idea who those people would be. They don't know who is at most risk of HIV infection or of transmitting HIV and they have never known. Or they have never been quite frank about it.
There are Modes of Transmission Surveys, but these are figures cobbled together from a disparate collection of assumption, guesswork, prejudice, overactive imagination and devotion to the tooth fairy. In the end, some Africans are more likely to be infected than others, but those the industry says are most likely to be infected are not the most likely, or they are not likely to be infected for the reasons the industry says.
The majority of infections in East African countries are in married couples and those in long term relationships. Many of these people are not promiscuous, many only have sex with their partner, they don't have sex very often and many of them even take precautions to prevent infection with HIV, other sexually transmitted infections and unplanned pregnancies. In other words, a disease that is difficult to transmit through any kind penile/vaginal sex is commonly transmitted through low-risk heterosexual sex.
An update from a recent conference doesn't mention the above issues. It is accepted that effectiveness is only moderate. But there is a tendency to believe that adherence will, almost miraculously, become better than anything every seen in the history of healthcare that focuses on technical fixes.
One only need look at the number of HIV positive people who die without treatment, the number who die on treatment, the number whose treatment has failed and they are seriously ill, the levels of resistance that are mounting up over the years, etc, to wonder where all the optimism about PrEP comes from. It may be great, but will it have a great impact, or any impact, where it is most needed?
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.
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.
Labels:
behavioral paradigm,
behvioural,
iatrogenic transmission,
nosocomial infection,
pep,
post-exposure prophylaxis,
pre-exposure prophylaxis,
prepwatch,
recreational drugs,
technical solutions,
unaids
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