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An unwise recommendation by the WHO.

July 20, 2014 Leave a comment

 

PrEP is an HIV prevention intervention in which antiviral medications are taken to interrupt sexual transmission of the virus. It is now being recommended by the WHO for, it seems all   sexually active gay men.  Actually it’s not quite that stark – they continue to recommend condom use as well.   Despite this, many will probably see this as a recommendation to rely on PrEP as an alternative to condoms.

 

The WHO recommendation is a population based proposal, a public health recommendation as opposed to recommendations for specific individuals.   Recommendations for individuals are different because they take into account individual circumstances, such as the extent to which a specific person is at risk.  Population based recommendations are recommendations made across the board, in the case of the WHO, addressed to all men who have sex with men.

 

While assuring us that the recommendations are evidence based and providing the customary explanation of how the strength of evidence is graded, we learn that the WHO has made a sweeping worldwide population based recommendation on evidence provided by just one randomized study!    This was the iPrEx study, which was beset with interpretative difficulties, not least because few took the medication as directed, if at all.

 

We simply do not know enough about PrEP to make a sweeping population based recommendation. .  We have little idea of what adherence to the medication might look like in various populations, we know little about the degree of protection in specific sexual acts.  Different sex acts carry different risks, for example, to the receptive or insertive partner in anal sex.   Also, how effective is PrEP  in situations of exposure to high and low viral loads.  In addition we have little idea of the extent to which condom use will be abandoned.

 

It’s clear that there is a widespread view that PrEP is an alternative to condoms, despite official recommendations stating that PrEP  should be part of a comprehensive prevention approach that includes condom use.

 

 

A more balanced response would have been a call for more research, and importantly, for a fuller description of those individual situations where PrEP use is a rational preventative intervention at the present time.

 

 

The use of PrEP by an individual is very different.     The degree of risk to individuals will vary considerably and on an individual basis PrEP use can be a completely appropriate intervention in situations of very high risk, even if we do not have precise information of its efficacy without condom use.   The use of  PrEP could also be considered when there is an inability to maintain an erection with a condom.  It might be an option to enable a fuller sexual expression among what is probably   a large number of men whose difficulty with condoms, for whatever reason,  stands in the way of satisfactory   sex.      Medical supervision is also more likely in individual situations. It is important to check for HIV infection and to monitor for sexually transmitted infections and drug toxicities.

 

 

Monitoring for sexually transmitted infections is important.  Since PrEP alone offers no protection from the transmission of infections that might be interrupted by condoms we might expect an increase in such infections with a wide roll out of PrEP.  The current increase in sexually transmitted infections among gay men in some cities is most likely attributable to an increase in unprotected sex.    Many sexually transmitted infections facilitate the transmission of HIV which may be another factor that could drive an increase in new HIV infections.

 

 

 

The way PrEP has been promoted during the past few years has surely contributed to the poor support received for prevention education.   One way in which this has happened is the shifting of budgets for prevention to those entities, private or government insurers that pay for drugs used in biomedical prevention.

 

There seems to be a widespread view that prevention education does not work.  But we know that it can work. The adoption of safe sex practices including condom use in the early 1980s curbed the spread of the epidemic, although admittedly conditions are not the same today.  There is little support for continued condom use, and rather than take the view that condoms don’t work, we might try to understand the obstacles that stand in the way of effective prevention education.

 

 

 

If prevention education has been ineffective it’s  be because there has been so little of it, and what little there is has not been properly targeted.  The move of the epidemic into African American communities during the 1990s  was occurring in plain view yet the federal government was churning out expensive vacuous untargeted prevention messages in the form of “America responds to AIDS,” a futile exercise that helped to discredit prevention education.

I get the sense that some younger gay men feel they have missed out in not experiencing the abandon of the 1970s and see PrEP as a way to make up for this.  The real lesson of the 1970s is that sex with multiple different partners on such a vast scale, as occurred in NYC in the 1970s, permits any pathogen that can be transmitted sexually to disseminate widely. That’s what started to happen with amebas and other intestinal parasites and HIV, and is happening with syphilis, gonorrhoea, herpes, hepatitis and many other infections.  There surely will be others beyond HIV.

 

Since we really have very little information about PrEP, and almost none about its use on a population level  such a broad recommendation by the WHO is absolutely inappropriate, so maybe  faced with increasing HIV  infections among gay men,  the WHO is simply giving up  and proposing an unproved intervention out of desperation.  When I say unproven, I mean it is unproven as a viable population based intervention.    Looked at this way, it’s a put down –  a response that may be no more than gestural to people who continue to harm themselves by refusing to use condoms in sex with partners of unknown sero status.

 

This unwise WHO recommendation may also have the effect of increasing new HIV infections if it results in an increase in unprotected sex where adherence is inadequate.

 

I hope there will be a critical look at the WHO panel and funders responsible for producing such unhelpful recommendations.

 

 

 

 

Treatment as Prevention: Protecting Individual Autonomy

Treatment as Prevention

Protecting  patient autonomy

Patient autonomy is just a particular instance of individual autonomy, a term that may sound pretty dry and academic but if we used the term individual freedom we would essentially be talking about the same thing.

Respect for the autonomy of the individual may be the most important of the principles that form the foundation of medical ethics. (1)

One attribute of personal autonomy is: “the capacity to be one’s own person, to live one’s life according to reasons and motives that are taken as one’s own and not the product of manipulative or distorting external forces.” (2)

There is no disagreement about the importance of respect for individual autonomy but as I’ll explain, it seems that its pre-eminence is being questioned in some proposals to use antiretroviral treatment to prevent transmission of HIV.

The recent demonstration that antiretroviral treatment can prevent transmission of HIV among serodiscordant heterosexual couples is great news.  However, when the person offered treatment has not yet been shown to personally benefit from it, an ethical issue needs to be addressed.   It has not yet been reliably demonstrated that for people with greater than 350 CD4 lymphocytes, starting treatment immediately rather than deferring it confers a net benefit; indeed, it may even prove to be harmful.   A randomized controlled trial now enrolling will provide needed information, but we will have to wait several years for its results.

The issue isn’t whether or not people with greater than 350 CD4 lymphocytes should receive treatment.  A respect for their autonomy requires that the decision whether or not to do so is made by them and is made free from coercion.

A recent issue of the Journal, Public Health Ethics (3) is devoted to ethical issues associated with the proposal that a program of universal testing and treatment of infected individuals could bring an end to the HIV/AIDS epidemic.  Such a proposal would involve the treatment of healthier HIV infected individuals not at this time known to personally benefit from antiviral medications which could even harm them.

In an article in the journal referred to above,  public health ethics  is said to require an approach where respect for individual autonomy is not paramount;  a commitment to the supremacy of individual autonomy could have no place where the “primacy of collective wellbeing is the starting point”.

In that case I wonder just how desirable a collective wellbeing would be where individual rights were subservient to whatever was defined as the collective good.

I can only hope that this goes nowhere, as abandoning the pre-eminence of respect for individual autonomy opens the door to tyranny, paternalistic or otherwise.  Individual freedoms have been hard won, and we should always be aware of harms that have been perpetrated in the name of the public good, even leaving alone the problem of who defines what constitutes the public good.

In public health, medical research and medical practice, concern for individual autonomy remains paramount.   The only commonly agreed acceptable exemption is the restriction of personal freedoms to prevent harm to others such as limiting the movement of individuals with highly communicable diseases where the harm that may be done to others is considerable.  That is, outside the criminal justice system, among individuals who are free.

People have the right to make decisions about their treatment, their participation in a research study, or in a public health intervention, free from coercion.   

Providing misleading information is a form of coercion; withholding information may also be coercive.

Providers of health care have an obligation to provide patients with honest information to inform their decisions.  This must include information about what is known about the risks and benefits of treatment, as well as what remains conjectural.

Information and the strength of the evidence upon which it rests:

 

It’s not enough to simply provide individuals with information concerning the benefits and risks of a particular treatment.  In order for the information to be useful we must also indicate the strength of the evidence on which the information rests. (4)

The most reliable evidence regarding the effects of a particular treatment is provided by results of randomized controlled clinical trials.  This is because the treatment in question has been put to the test in a protocol that minimizes bias; we can therefore have a greater degree of confidence that effects observed are in fact caused by the treatment.

Unfortunately information derived from randomized controlled trials is often unavailable.  The clinical trial may not yet have been completed, or for whatever reasons the trial cannot be undertaken.

When this is the case we have to consider evidence of inferior quality, for example, evidence derived from reviews of patient records or observational studies, and the opinion of experts.

Observational studies are beset with interpretative difficulties because subjects are not randomly assigned to receive one or another kind of intervention.  The particular reasons why participants were selected for study may influence the outcome rather than the effects of the intervention.

Expert opinion:

In all the systems I have seen that grade the quality of different kinds of evidence, expert opinion is at the bottom of the list.    But expert opinion can be valuable to an individual in coming to a treatment decision when evidence of the highest quality is not available.

Respect for patient autonomy means that patients make their own decisions free from coercion.  As noted, supplying misleading information is a form of coercion.   To state that something is known to be the case, when it is only an opinion is misleading.

HPTN 052

HPTN 052 is the study which demonstrated the efficacy of antiretroviral treatment in preventing transmission of HIV among serodiscordant heterosexual couples.  Although the result was not unexpected it is nonetheless significant because it was obtained from a randomized controlled clinical trial.

We now know that the uninfected partners of individuals with greater than 350 CD4 lymphocytes will benefit from treatment of the HIV positive partner.  At this time we can only have an opinion about whether starting treatment immediately or deferring it will benefit or harm the infected partner with greater than 350 CD4s or be without effect – apart from cost.

Most of the jubilant reports of the results of HPTN 052 do not mention the problem facing the healthier HIV positive partner in coming to a decision.  Do the commentators just assume that it’s been established that all infected individuals receive a net benefit from treatment irrespective of CD4 numbers?  Or do they not believe it to be important that patients make their own decisions regarding their treatment?

I wish I could say I was startled to read in one newsletter that “For treatment as prevention to work….. people need to be convinced that early treatment is in their interest.”

Convincing people to take a possibly perilous course of action based merely on opinion and evidence of inferior quality is a step on a road that ends with enforcement.

A respect for individual autonomy means that we respect the right of individuals to make decisions on their own behalf, free from even subtle coercion.  Our obligation as providers of health care information is to not only provide information, but also an indication of the quality of the evidence supporting it.

At this time we do not know that individuals with greater than 350 CD4 lymphocytes receive a net benefit from antiviral treatment.  There is evidence that they may, but until this is put to the test in a randomized controlled trial such as START, we must not mislead them by trying to convince them that “early treatment is in their interest”.

Given adequate information, a person with greater than 500 CD4 lymphocytes may reasonably decide to take antiretroviral drugs to lessen the risk of infecting a partner even knowing that there may be no personal benefit or that there is a possibility of harm.

Whenever treatment is offered for any reason other than for a person’s benefit, and where it has not yet been reliably demonstrated that there will be a net benefit, a consent process should be required.  I doubt though that this will happen.

At the end of the day what’s of central importance is that we respect our patient’s right to make choices about his or her treatment, and provide honest information to inform that choice, recognizing the difference between expert opinion and established fact.

(1)    Ever since Beauchamp and Childress published the first edition of their classic text, Principles of Biomedical Ethics, in 1979 it’s been commonly accepted that beneficence, nonmaleficence, justice and respect for autonomy, are four principles that should guide medical ethics.

The Four Principles are general guides:

Respect for autonomy: respecting the decision-making capacities of autonomous persons; enabling individuals to make reasoned informed choices.

Beneficence: this considers the balancing of benefits of treatment against the risks and costs; the healthcare professional should act in a way that benefits the patient

Non maleficence: avoiding the causation of harm; the healthcare professional should not harm the patient. All treatment involves some harm, even if minimal, but the harm should not be disproportionate to the benefits of treatment.

Justice: distributing benefits, risks and costs fairly; the notion that patients in similar positions should be treated in a similar manner.

Beauchamp and Childress; Principles Biomedical Ethics, OUP, 5th edition

(2)   Christman, J, 2001″Autonomy in Moral and Political Philosophy”, The Stanford Encyclopedia of Philosophy (Fall 2007 Edition) , Edward N. Zalta (ed.), URL = <http://plato.stanford.edu/archives/fall2007/entries/autonomy-moral/&gt;.

(3)    http://phe.oxfordjournals.org/content/3/3.toc

(4)   Several systems have been devised to grade the quality of evidence.For example:  http://www.cebm.net/index.aspx?o=1025 The GRADE working group has been working on assessing the quality of evidence since 2000. http://www.gradeworkinggroup.org/index.htm

The AZT trial that led to FDA approval

March 27, 2011 1 comment

I’m moving some posts from aidsperspective.net/blog as there have been difficulties accessing that blog.   This was originally posted there on January 28th 2011., with a similar  but shorter article on my POZ  blog.

The clinical trial that led to the approval of AZT for the treatment of AIDS in 1987 is a landmark event, not only in the field of HIV medicine but I believe it had a major impact on the drug regulatory process that has had effects in all fields of clinical medicine.

The trial reported in the New England Journal of medicine, had produced a dramatic result (1). Before the planned 24 week duration of the study, after a mean period of participation of about 120 days, nineteen participants receiving placebo had died while there was only a single death among those receiving AZT.   This appeared to be a momentous breakthrough and accordingly there was no restraint at all in reporting the result; prominent researchers triumphantly proclaimed the drug to be “a ray of hope” and “a light at the end of the tunnel”.   Because of this dramatic effect, the placebo arm of the study was discontinued and all participants offered 1500mg of AZT daily.

I was treating many HIV infected individuals in 1987 when the drug was approved for the treatment of advanced AIDS.  I was puzzled by the results of the trial quite simply because those patients of mine who resembled trial participants would not have died in the period before the placebo arm was terminated.   Many patients enrolled in the trial had experienced an episode of pneumocystis pneumonia within four months of participation.  My patients and those of other experienced physicians were unlikely to die within four months of an episode of this type of pneumonia.

This means that if my patients had enrolled in the trial it’s probable that there would have been no deaths at all by the time the placebo arm was discontinued and thus an apparent dramatic effect of AZT on mortality would not have been seen.

There had to be an explanation for the discrepancy between the outcome of my patients (and those of other experienced physicians) and individuals participating in the trial; I was confident that an academic clinical researcher would sort this out.

But no explanation was forthcoming.

I was then able to obtain a copy of the application submitted to the FDA by Burroughs Wellcome, (the NDA) and tried to understand the discrepancy myself.

I reviewed the report as a primary care provider to people with AIDS, and thus challenged very aggressively, both by my colleagues and by many patient advocates, to prescribe AZT.  I also reviewed the report as a clinical researcher who had designed and implemented clinical trial protocols.

This is the report I wrote after reviewing the NDA. (1)

Essentially it makes the point that patient management strategies were the most significant factor influencing mortality, at least in the short term, and it could not be excluded that differences in the ways patients were managed in the trial, were to a greater or lesser extent, responsible for survival differences.  Patient management in this context refers to all the measures available, before the introduction of specific antiviral therapy, to care for individuals susceptible to infections and malignancies associated with impaired cell mediated immunity.   For example, the speed with which a potentially fatal opportunistic infection is suspected and diagnosed and efficiently treated can make the difference between life and death.   Much experience in the treatment of immunocompromised individuals had been gained before the AIDS epidemic, particularly in the field of renal transplantation, but also in other conditions.

The AZT trial took place in 12 centers across the country.  There was no uniform approach to patient management during the trial; each of the 12 medical centers approached the most important determinant of life and death in the short term, independently.

I will return to the implications of this lack of uniformity in patient management strategies.

It may seem surprising today that so little attention was paid to developing methods for the optimal day to day care of patients with AIDS, but at the time there was a pervasive defeatist attitude concerning treatment.    All too commonly it was felt that nothing could be done to halt the inevitable progression of the disease to its fatal end.

I’m not sure that it’s even possible to adequately describe the terror and desperation felt in the early 1980s.   At that time doctors on the front lines were trying to do what they could for their patients but had received little help from experts at academic medical centers and virtually none at all from Government scientists, although by 1981 when the first AIDS cases were reported,  diseases of the immunocompromised host had already become a distinct medical subspecialty.

But by 1986 nothing of any use regarding treatments had come from the Public Health Service.  For example, people with AIDS had to wait until 1989 for the CDC to issue guidelines for the prevention of pneumocystis pneumonia, the most frequent cause of death among them, while this type of pneumonia had often been routinely prevented in many other individuals who were also at risk because they were recipients of kidney transplants, or were children with leukemia.  The means to prevent pneumocystis pneumonia had been published in 1977.

Some community doctors were not waiting for recommendations from government scientists or from their colleagues in academic medical centers, and were learning how to care for their patients. I and several colleagues were preventing pneumocystis pneumonia among our patients for many years before the Public Health Service got around to making their recommendations.

Those who had taken on the medical leadership of the epidemic were telling us in their silence that there was nothing much we could do – we just had to wait for a drug.

Then, after six years of silence regarding treatments Government scientists at last told us that help was on the way.  Dr Samuel Broder who was head of the National Cancer Institute appeared on television shows trumpeting the benefits of a drug he called Compound S.   I well remember a TV show where he appeared with an AIDS patient who enthusiastically attested to the benefit he had received from the drug, presumably from 1.5G of AZT daily.

A note about patient management strategies:

There really was a lot that we were able to do for our patients before the advent of specific antiviral therapy.    After all, most deaths were caused by opportunistic infections, and we certainly could do a great deal to prevent and treat many of them.

Without much guidance some doctors with large practices were able to develop structured programs of patient care.   These included the prevention of opportunistic infections when possible, the determination of susceptibility to some, and their early diagnosis and aggressive treatment.

All too often symptoms, particularly diarrhea, fever, weight loss, and anemia were simply attributed to AIDS and not investigated. In fact, such symptoms could frequently be ameliorated if their causes were aggressively sought.  More often than not they were caused by treatable conditions.   So, patient management strategies included aggressively trying to establish the causes of such symptoms and treating them.

It was the experts who in fact were more likely to attribute them to AIDS and therefore consider them to be untreatable

The provision of general support, including attention to nutrition and mental health issues are parts of patient management.

All of this is pretty labour intensive doctoring, but these measures were able to prolong the lives of our patients.

Needless to say, it was community doctors who had to develop such strategies without much help from the experts. I suppose one has to conclude that the government medical leadership of the response to the epidemic, unlike community doctors dealing with it, must have felt that nothing could be done for people with AIDS, that the only hope to be found was in a new drug.

Returning to the original AZT trial:

If in the short term patient management strategies can make the difference between life and death is there any reason to consider that such strategies may have differed in those receiving placebo or AZT?

The reason why randomized placebo controlled clinical trials are blinded, (so that neither investigator nor participant knows who is receiving placebo or active drug) is to minimize bias.  Bias can influence the outcome that might incorrectly be attributed to a drug effect.   But it’s impossible to blind a trial using AZT.  The drug causes changes in routine blood counts that investigators need to see.   Therefore we must conclude that investigators could know who was receiving AZT or placebo.   The FDA reviewer was aware of this.

If patient management is the most important determinant of mortality in the short term, could bias have influenced the ways patients were managed?

Unfortunately, because this was essentially an unblinded trial, the answer is yes.

Patients known to be taking AZT or placebo might have unintentionally been treated differently, with either greater or lesser care, when the investigator was also the treating physician.  AZT may therefore have been even more effective than claimed or may have been worse.

In some centers there would have been instances where the participant also had a personal physician.   There was no analysis of trial outcomes based on this difference. Of course from what I have written, I would expect that mortality was probably confined to those participants who did not have a personal physician, but were treated by the study doctor.

But who knows? Information must still be available regarding mortality at different study centers, and in relation to whether the participant was treated by the study doctor or had a personal physician.

Dr Fischl was the principal investigator of the trial but I don’t know if she and her team at the University of Miami were the treating physicians as well as the trial investigators.

Incidentally this also brings up the important question of   the propriety of an individual serving as both investigator and treating physician. I believe these two roles are often incompatible; that there can be an insuperable conflict of interest that should preclude an individual from functioning in these two roles concurrently.  I have served in both capacities but in most instances, not simultaneously.

The survival benefit in the trial attributed to AZT   may therefore, to a greater or lesser extent have been due to differences in how placebo or AZT recipients were managed.  All we can say is that the question remains, not that this was in fact the case.

The problems resulting from unblinding were clearly acknowledged by the FDA reviewer but not by the study investigators.   Around the time of the trial report I took part in a Canadian Broadcasting Corporation telephone interview.  When I tried to bring up the issue of bias I was cut short by a NIH official who said this was too technical a detail for the audience!

Very unfortunately, the most vocal of the critics of the AZT trial included some individuals who believed that HIV could not cause AIDS.   Their strident criticisms were unhelpful; it was evident that none of these critics had any experience in clinical trial methodology.

It was immensely disappointing to find that many of the problems in the trial were identified by Ellen Cooper, the FDA reviewer, yet the drug was still approved at a dosage that proved to be so toxic that another trial compared a similar dose with half that dose. This exercise resulted in excess deaths among those taking the higher dose. (A randomized controlled trial of a reduced daily dose of zidovudine in patients with the Acquired Immunodeficiency Syndrome. Margaret A Fischl et al. NEJM 1990: 323:1009-14).

Among the many bizarre aspects surrounding the introduction of AZT was the claim that the excess deaths in those receiving the higher dose were due to AIDS – that in the case of AZT, less is better – the explanation given for the superiority of the low dose compared to the high dose was that the lower dose allowed people to remain on the drug for longer – not even a hint that the higher dose contributed to the increased mortality.  Here is the representation of the mortality differences between the two dosages:

It’s worth reproducing the disingenuous words in which this is stated.

“The findings in this study indicate that a lower daily dose of zidovudine is at least as effective ………as the initially tested dose of 1500mg per day and is less toxic”  “Moreover low dose therapy was associated with a better survival rate” “The reason for this better interim survival is not certain, but is most likely related to the greater likelihood that continuous antiviral therapy can be maintained with lower doses of zidovudine”

If ever evidence was needed that AZT – at the initial recommended dose of 1500mg daily probably caused an excess mortality – the figure above provides it, despite the disingenuous claims of the authors that the deaths were due to AIDS.  A rational response would have been to work out the minimum effective dose. Why stop at 600mg a day? 300mg a day is probably just as good.  It is the dose I prescribed with no evidence that 300mg AZT daily was associated with a worse outcome.  As described in another article it is likely that endogenous interferon plays a role in pathogenesis, and AZT promptly removes it from the circulation

That the possibility that more people on the higher dose died from AZT toxicity  is not even mentioned in the above report is a sad indication of what has become of the discussion of results section in a scientific paper, at least in the field of AIDS. Traditionally all reasonable possibilities are discussed, even to be dismissed, but not in this paper.

The publicity following the approval of AZT was huge. Doctors received a video where AZT was billed as “A ray of hope”. I recall white coated doctors speaking about the “light at the end of the tunnel”.

The dosage schedule was absurd.  There was no scientific basis at all for four hourly dosing.  AZT was to be taken even at night, and patients were given beepers to remind them to take their medicine exactly at the appointed time.   AZT is not the compound that blocks HIV replication. It is changed into the active compound within the cell by the addition of phosphate, and so blood levels tell you nothing about the levels of the active form in the cell. It is also a little gruesome – because as it turned out adherence to this difficult ritual was associated with great toxicity, and I can imagine that sometimes the manifestations of this toxicity would be attributed to AIDS and patients encouraged to still keep their beeper going and continue to take AZT.  At first the drug was only available if patients met certain criteria, and I know colleagues, devoted to their patients, who forged the papers to enable their patients to get the huge dose of AZT.   All on the basis of an approval based on a terribly flawed trial.

Of course the need for some therapy was quite desperate and one must wonder if this desperation lowered the threshold of what was deemed to be acceptable, so that there was perhaps less scrutiny of the trial and the failures of AZT at the dose used – until of course toxicity forced a reconsideration of the dosage.

The approval of AZT also set an important precedent that seemed to go unnoticed at the time, and indeed has escaped comment subsequently.

AZT was the first drug of its kind to be approved for lifelong human use.

The drug  is an analogue of thymidine which is a normal building block of DNA.  It is incorporated, instead of thymidine, into DNA during its synthesis, and then immediately stops further DNA chain elongation because nothing can be added to it.

The use of such analogues able to disrupt DNA synthesis was considered to be perilous when I first dealt with them in the 1960s.  I had used them in the virology laboratory in experiments conducted in vitro, and they were handled with caution, as potentially hazardous substances.

In clinical practice, apart from acyclovir which is a similar drug, but in a special category,   such analogues were used systemically in malignancies and some viral infections – such as herpes encephalitis or neonatal herpes, but only for short periods.  Acyclovir is in a different category as it can only be used by the herpes virus enzymes, and has no effect in cells not infected with herpes viruses.    The idea of a possibly lifelong exposure to a DNA chain terminating compound – or even an analogue that is incorporated into DNA that continues to be synthesized, was I believe a novel concept at that time. To emphasize, what was novel was not the use of such compounds, but a life time exposure to them. .    So, I was somewhat concerned at the very idea of this approach, and also found it strange that colleagues were mostly silent on this issue.  These analogues need to undergo changes in the cell, and are added to the growing DNA chain by enzymes, either those that belong to the cell, or enzymes that are specific to the virus, such as the reverse transcriptase of HIV.  It was hoped that AZT, which is turned into its active form by cellular enzymes, would be preferentially used by the viral rather than the cell enzymes that synthesize DNA, and therefore not terminate cellular DNA synthesis; there was some evidence to support this. HIV’s reverse transcriptase adds AZT to the viral DNA chain, while cellular enzymes add it to cellular DNA. Cell DNA is found in two different sites. In the nucleus it is the DNA that constitutes our genome – that is all the information that determines our inherited characteristics. DNA is also found in cellular structures called mitochondria which are the source of the energy needed by the cell. Two different enzymes are needed to make DNA in each situation. While there was comforting evidence that AZT much preferred the viral reverse transcriptase to the enzyme that makes our genomic DNA, this preference was less evident in the case of the enzyme that makes mitochondrial DNA. In fact much of the toxicity of AZT is a result of its effect on mitochondrial DNA synthesis.

I never prescribed AZT when it was first approved, and when I did it was at a dose of 300mg a day.  Because I was one of the few physicians around 1987 who did not prescribe AZT I attracted patients who were reluctant to take it and whose physicians were nor supportive of this choice.  I also received severe criticism for my position

This original AZT trial did however clearly demonstrate to me how important patient management strategies were in the treatment of AIDS, particularly in the days before the more potent antiviral drugs became available.

The New England Journal of medicine, which reported the original trial, rejected my review. I sent copies to all the clinicians who were prominent in the field – as well as to several patient advocates. There was not a single response – not even to reject the points I made.  Just total silence.  Realizing the difficulty in publishing independent material we – myself and mostly Michael Callen , decided to publish an independent journal.  We called it AIDS Forum. Michael was the editor, and it lasted for three issues.

One last comment on the baneful effects of this trial:  While it was not responsible for the undue influence industry has on medical practice, this trial probably provided the greatest impetus towards the sad situation we are in today. It is possible that in the field of HIV medicine, industry had its greatest opportunity to establish a firm hold on many different ways to influence practice. These include not only marketing strategies, but influence on guidelines committees, support of continuing medical education, the support of medical conferences and influence on reports of their proceedings, as well as the invention of the Key Opinion leader or KOL, to provide information to physicians.    “Key Opinion Leader” is not the only absurd designation in this field.  We also have “Thought Leader”.  Needless to say these distinctions are not conferred by any academic institution; I would assume that the marketing departments of pharmaceutical companies are responsible for choosing who deserve these titles.

(1)

N Engl J Med 1987; 317:185-191July 23, 1987

USPHS guidelines:We need reliable evidence to justify an earlier start of anti-retroviral therapy.


The most recent revision of the US Department of Health and Human Services (DHHS) guidelines for the treatment of HIV/AIDS recommended initiation of anti-retroviral treatment at a CD4 count of 500.

This recommendation was made in the absence of evidence from a prospective randomized clinical trial.   Instead, evidence of inferior quality was relied on.

Much is at stake for HIV infected individuals.  The point in the course of HIV infection when treatment is initiated can affect the duration and quality of life.

Rather than issuing interim guidelines pending the completion of a prospective randomized trial the guidelines committee has jumped the gun, relying on evidence of inferior quality.

In the following article, John Falkenberg reminds us of the harm that has resulted from basing recommendations on observational cohort studies.

—————————————————————————————

John Falkenberg  New York, NY

Doctors and patients always have the right to choose treatment that is not based on data generated from well-designed clinical trials.  However, I worry when treatment guidelines are based on cohort studies or anecdote, and it’s alarming when the city of San Francisco and Project Inform endorse that practice.

No study is cited more often than NA-ACCORD, an observational cohort study, to support early antiretroviral therapy.  Besides the many historical examples of harm caused by treatment guidelines based on observational studies (see the Nurses’ Health Study, below), NA-ACCORD suffers from more than the self selection bias of observational studies:  a large percentage of the deferred treatment group, approximately 45%, did not initiate therapy and/or did not have a decline in CD4 counts.  How can those findings be extrapolated to clinical practice?  In addition, the early treatment group may have had incomparable medical care.  For example, were lipids more carefully monitored in that group resulting in more aggressive use of statins, a class of drug with pleiotropic effects that include improving endothelial function, enhancing the stability of atherosclerotic plaques, decreasing oxidative stress and inflammation, and inhibiting the thrombogenic response.  These drugs have demonstrated morbidity and mortality benefits in clinical settings where lipid levels are normal.

The history of HIV treatment guidelines is an excellent reminder of the risk of formulating guidelines based on observational studies and anecdotal evidence.  However, HIV is not the best example.  There are clinical settings where “more compelling” cohort data using medications considered relatively safe served as the basis for treatment guidelines that ultimately were proven wrong at a significant cost.

I think the best example pertains to the use of hormone replacement therapy (HRT) in postmenopausal women.  There were many anecdotal, observational and retrospective reports of the many benefits of HRT, but the Nurses’ Health Study was the flagship.  The Nurses Heath Study was a case control, observational study of over 120,000 nurses, including over 20,000 who were post menopausal.  As the follow up continued for years, an increasing number of women reached menopause, and various health variables were monitored and reported.  The most striking “conclusion” of this study was that the relative risk of death was 0.63 in HRT users vs. non users.  The risk of major coronary artery disease among HRT users was 0.60 when compared to those who never used HRT.  Both of these findings were statistically significant.  These data were broadly reported in medical journals, and professional meetings.  The data were added to the HRT prescribing information and aggressively promoted by the pharmaceutical industry, particularly the manufacturer of Premarin (American Home Products, renamed Wyeth, recently acquired by Pfizer), the most widely prescribed HRT.

There was huge resistance to conducting a prospective randomized controlled trial in this population.  “It denies the placebo-controlled group the protective heart benefits of HRT.”  “It is unethical to randomize people who would clearly benefit from HRT to placebo.”  “No one would enroll in this trial considering what we already know about the benefits of HRT in this population.”  Despite the criticism, the Women’s Health Initiative, a prospective randomized controlled study of HRT in postmenopausal women was conducted.  In July 2002 the study was halted early due to a statistically significant excess risk of heart attack, stroke and breast cancer in those receiving HRT versus those on placebo; a finding that literally rocked the world of HRT.

More recently, long-term treatment recommendations in diabetes were debunked by results from the first well designed, randomized controlled study (coincidently named ACCORD), with cardiovascular clinical endpoints.  Using multiple medications for intensive glucose lowering and intensive blood pressure reduction did not reduce cardiovascular events but only increased adverse events.  Once again, guidelines formulated without data derived from controlled clinical trials did more harm than good.

There is a lot at stake here and I fear that this is déjà vu all over again.  The NA-ACCORD results are compelling and generate a hypothesis that needs to be tested, but the clinical trial has yet to be performed and the evidence is absent.  I find it difficult to understand why those of us who have lived during decades of this epidemic, who have seen those living with HIV experience a wide range in the rate of disease progression, and who have seen the rise and fall of early antiretroviral therapy, do not demand more.  I’m shocked by both the city of San Francisco and Project Inform.

I cannot claim to know the motivation behind the current push for early treatment without evidence.  However, I do know the pressure felt by the pharmaceutical industry as they approach a patent cliff with little in the advanced research pipeline and significant overcapacity.  It is not coincidental that lobbying efforts have been stepped up in an economic climate where value driven medicine is a new priority.  That lobbying includes an aggressive push to eliminate informed consent for HIV testing and a push for early treatment.  And, here we are with major public health agencies and CBO’s jumping on the bandwagon without the evidence

We need reliable evidence to justify an earlier start of anti-retroviral therapy. May, 2009


The most recent revision of the US Department of Health and Human Services (DHHS) guidelines for the treatment of HIV/AIDS recommended initiation of anti-retroviral treatment at a CD4 count of 500.

This recommendation was made in the absence of evidence from a prospective randomized clinical trial.   Instead, evidence of inferior quality was relied on.

Much is at stake for HIV infected individuals.  The point in the course of HIV infection when treatment is initiated can affect the duration and quality of life.

Rather than issuing interim guidelines pending the completion of a prospective randomized trial the guidelines committee has jumped the gun, relying on evidence of inferior quality.

In the following article, John Falkenberg reminds us of the harm that has resulted from basing recommendations on observational cohort studies.

—————————————————————————————

John Falkenberg  New York, NY

Doctors and patients always have the right to choose treatment that is not based on data generated from well-designed clinical trials.  However, I worry when treatment guidelines are based on cohort studies or anecdote, and it’s alarming when the city of San Francisco and Project Inform endorse that practice.

No study is cited more often than NA-ACCORD, an observational cohort study, to support early antiretroviral therapy.  Besides the many historical examples of harm caused by treatment guidelines based on observational studies (see the Nurses’ Health Study, below), NA-ACCORD suffers from more than the self selection bias of observational studies:  a large percentage of the deferred treatment group, approximately 45%, did not initiate therapy and/or did not have a decline in CD4 counts.  How can those findings be extrapolated to clinical practice?  In addition, the early treatment group may have had incomparable medical care.  For example, were lipids more carefully monitored in that group resulting in more aggressive use of statins, a class of drug with pleiotropic effects that include improving endothelial function, enhancing the stability of atherosclerotic plaques, decreasing oxidative stress and inflammation, and inhibiting the thrombogenic response.  These drugs have demonstrated morbidity and mortality benefits in clinical settings where lipid levels are normal.

The history of HIV treatment guidelines is an excellent reminder of the risk of formulating guidelines based on observational studies and anecdotal evidence.  However, HIV is not the best example.  There are clinical settings where “more compelling” cohort data using medications considered relatively safe served as the basis for treatment guidelines that ultimately were proven wrong at a significant cost.

I think the best example pertains to the use of hormone replacement therapy (HRT) in postmenopausal women.  There were many anecdotal, observational and retrospective reports of the many benefits of HRT, but the Nurses’ Health Study was the flagship.  The Nurses Heath Study was a case control, observational study of over 120,000 nurses, including over 20,000 who were post menopausal.  As the follow up continued for years, an increasing number of women reached menopause, and various health variables were monitored and reported.  The most striking “conclusion” of this study was that the relative risk of death was 0.63 in HRT users vs. non users.  The risk of major coronary artery disease among HRT users was 0.60 when compared to those who never used HRT.  Both of these findings were statistically significant.  These data were broadly reported in medical journals, and professional meetings.  The data were added to the HRT prescribing information and aggressively promoted by the pharmaceutical industry, particularly the manufacturer of Premarin (American Home Products, renamed Wyeth, recently acquired by Pfizer), the most widely prescribed HRT.

There was huge resistance to conducting a prospective randomized controlled trial in this population.  “It denies the placebo-controlled group the protective heart benefits of HRT.”  “It is unethical to randomize people who would clearly benefit from HRT to placebo.”  “No one would enroll in this trial considering what we already know about the benefits of HRT in this population.”  Despite the criticism, the Women’s Health Initiative, a prospective randomized controlled study of HRT in postmenopausal women was conducted.  In July 2002 the study was halted early due to a statistically significant excess risk of heart attack, stroke and breast cancer in those receiving HRT versus those on placebo; a finding that literally rocked the world of HRT.

More recently, long-term treatment recommendations in diabetes were debunked by results from the first well designed, randomized controlled study (coincidently named ACCORD), with cardiovascular clinical endpoints.  Using multiple medications for intensive glucose lowering and intensive blood pressure reduction did not reduce cardiovascular events but only increased adverse events.  Once again, guidelines formulated without data derived from controlled clinical trials did more harm than good.

There is a lot at stake here and I fear that this is déjà vu all over again.  The NA-ACCORD results are compelling and generate a hypothesis that needs to be tested, but the clinical trial has yet to be performed and the evidence is absent.  I find it difficult to understand why those of us who have lived during decades of this epidemic, who have seen those living with HIV experience a wide range in the rate of disease progression, and who have seen the rise and fall of early antiretroviral therapy, do not demand more.  I’m shocked by both the city of San Francisco and Project Inform.

I cannot claim to know the motivation behind the current push for early treatment without evidence.  However, I do know the pressure felt by the pharmaceutical industry as they approach a patent cliff with little in the advanced research pipeline and significant overcapacity.  It is not coincidental that lobbying efforts have been stepped up in an economic climate where value driven medicine is a new priority.  That lobbying includes an aggressive push to eliminate informed consent for HIV testing and a push for early treatment.  And, here we are with major public health agencies and CBO’s jumping on the bandwagon without the evidence

AIDS Pathogenesis: HIV disease has characteristics of positive feedback systems

April 2, 2010 Leave a comment

2nd April,  2010

There is a similar and slightly extended version of this post on the blog I have on the POZ website. It’s in two parts:

Part 1

Part 2

HIV infection and many other infections caused by a wide variety of microorganisms have a mutually enhancing relationship that is characteristic of positive feedback systems.

Although the reciprocal enhancing effects of HIV and other infections have been frequently described since the late 1980s, it is useful to explicitly recognize these as positive feedback systems as this highlights the implications they have for treatment of individuals and for control of the epidemic.  Explicitly recognizing the positive feedback characteristic of HIV disease also provides a way of looking at pathogenesis that can suggest further studies, both clinical and laboratory, that might advance our understanding of mechanisms of disease acquisition.

This is an illustration of positive feedback.    A stimulates B which in turn stimulates A. In this way the effects of A and B are increased.

The infections associated with the immunological disorders of HIV disease are generally, but not solely, caused by microorganisms that replicate within cells.     Many of the organisms that cause these infections survive in healthy people without causing disease, prevented from doing so by a competent immune system.   When the immune system fails these infectious agents start to divide.   They may then cause disease.  An additional effect of some of these active infections is to accelerate the replication of HIV.  Several mechanisms are responsible for this effect, which can then result in further immunological deterioration.

In addition, co-infection with many of the pathogens that also affect individuals with intact immune systems can also promote HIV replication.

Not all co- infections result in a more rapid progression of HIV disease.  Many have no effect and a few have even been reported to cause a temporary improvement of HIV disease.    This may be the case with measles, scrub typhus and a form of transfusion associated hepatitis.   But more often, when an effect of a co-infection has been noted, it has been to promote HIV disease progression.

Different co-infections can therefore affect the course of HIV disease in different ways.  Some may have no impact on the course of HIV disease; a few may possibly cause a temporary amelioration.   Those that are able to accelerate it are highly prevalent in HIV infected individuals.

Worldwide, viruses of the herpes family are probably the most important of the co-infections that interact with HIV in a mutually enhancing fashion. .    Virtually all adults are infected with some of these viruses that usually exist in a latent or dormant state.  They are readily activated in the setting of HIV infection and then promote further HIV replication by a number of different mechanisms.

In developing nations a range of different endemic infections, depending on geography, may be just as important; many can also accelerate HIV disease progression.  Conversely, HIV infection can promote progression of some  endemic infections.

Several different mechanisms have been uncovered that can explain the effects of co-infections on promoting HIV replication.    With such a wide range of infections, the precise ways in which each do this will vary in detail.

However there is one characteristic possessed by all HIV potentiating infections.  This is their ability to add to the immune activation that is a feature of progressive HIV disease.

By now I think it is generally accepted that chronic immune activation not only results from HIV infection but is a major contributor to the pathogenesis of HIV disease.   A state of sustained high level immune activation is the basis of the chronic inflammation and immunologic deterioration characteristic of progressive   HIV disease.

But what exactly is immune activation?

Immune activation refers to those changes that take place in the immune system when exposed to an infectious agent that allow it to eliminate or control the infection.  Essentially, the immune system is activated from a resting state to fight an infection.   Generally this process will last for days until the infection is overcome, and usually but not always, is followed by a lifelong immunity to the infectious agent.

However in progressive HIV disease the immune system continues to be activated at a high level and it is this sustained immune activation that eventually results in disease.   An activated state of the immune system is characterized by differentiation of precursor immune system cells.  Differentiation is the process by which these cells develop specialized functions.   Examples of cells that have acquired specialized functions are those that produce specific antibodies, or those with the ability to kill other cells infected with specific microorganisms.   Proliferation of immune system cells is an important characteristic of an activated state.  This is usually a short-term response subsiding with control of the infection that stimulated it.  But in progressive HIV disease, proliferation is sustained, probably with episodic cycles of further accelerations, and this continued proliferation contributes to the loss of immune system cells.

These cellular changes, differentiation and proliferation, are associated with the secretion of a variety of cytokines.  Cytokines are molecules that can change the behaviour of cells by binding to specific receptors on their surfaces, for example, causing them to divide.  Once released, cytokines not only attach to receptors on other cells but can also come back and attach to the receptors on the cell that produced it.

The cytokines that are released   have widespread effects.  Importantly, they include those that are associated with inflammatory changes, – the pro-inflammatory cytokines.    With respect to positive feedback, pro-inflammatory cytokines including IL-6 and TNF alpha are able to accelerate HIV replication.

A part of the immune system, the innate immune system, responds immediately to infection by recognizing molecular patterns common to different organisms.  The more familiar adaptive immune system responds to specific characteristics unique to each organism.

The innate immune system is also activated in untreated HIV infection.   Interestingly effects of activation of innate immunity were recognized very early in the epidemic, even before HIV was discovered, and so are among the earliest recognized AIDS related immunological abnormalities.  Activated innate immunity is responsible for the large amounts of alpha interferon in the circulation of people with untreated HIV/AIDS, first noted in 1981, the year this disease first came to our attention[i].   At that time the origin of this endogenous interferon was not known.   For a period, elevated levels of beta 2- microglobulin were regarded as an adverse prognostic marker.  This molecule can be regarded as a surrogate marker for interferon.   The association of interferon with abnormalities characteristic of this disease – including low CD4 numbers was also reported in the first 2-3 years of the epidemic[ii].   Over twenty years later mechanisms have been discovered that can explain the participation of interferon in the disease process[iii].

Interferon appearing in the circulation in untreated HIV disease may even be the first marker of immune activation noted, although not recognized as such when first observed

The changes that occur on activation of the immune system are associated with many other markers that can be measured.    Different molecules appear on the surface of activated cells.  These can be detected and measured, as can the cytokines associated with immune activation.

These measurements can tell us the extent of immune activation.   Importantly, the degree of immune activation parallels the rate of HIV disease progression.

Although it is now accepted that the consequences of continued activation and proliferation of immune system cells contribute to the loss of CD4 cells and the development of disease, the precise way it does so is not yet known, although there  are a number of different mechanisms  that could account for it.  The   associated inflammation also has adverse effects beyond the immune system.   For more detailed information on these mechanisms there are references to two reviews at the end of this article[iv].

Sustained immune activation is therefore at the heart of HIV/AIDS pathogenesis.   It is the sustained nature of the activated state that is critical.  Short lived states of immune activation are of course beneficial allowing us to recover from infections.  But in progressive HIV disease the process continues at variable rates.   Understanding what causes continued immune activation is central to an understanding of the pathogenesis of HIV disease.

What causes Immune activation?

While infection with HIV may start the process, other causes of immune activation are almost certainly also necessary to keep it going.

The following all contribute:

1:            The immune response to HIV itself.   This includes both innate and adaptive immune responses.  As noted above, adaptive responses are the familiar specific antibody and cell mediated responses that provide generally lifelong immunity to specific infectious agents.  Innate responses depend on recognition of molecular patterns common to several organisms.

Some suggest that HIV contributes directly to immune activation through binding of some of its proteins to immune system cells.

2:            Microbial products that can penetrate into the intestinal wall as a result of damage caused by HIV.  These microbial products then activate immune system cells.

3:            Other infections.

Some like active herpesvirus infections or the more traditional opportunistic infections can be seen as indirect effects of HIV infection.

Others are infections that can cause disease in people with intact immune systems like the endemic infections in developing nations. Some of these can be more severe in the setting of HIV infection.

Infections that can accelerate HIV replication include those caused by bacteria, viruses, protozoa and helminths.

Those that promote HIV disease progression can  usefully be  described in three categories.

A:            Herpes virus infections.   These are probably the most important worldwide.  Virtually 100% of adults are infected with some of them.     They represent infections that are more often latent, but are  readily activated  in HIV infected individuals.

B:            Endemic infections caused by a variety of different microorganisms than promote HIV disease progression and HIV replication.   These are important in developing nations.

C:            Other infections.  These include the opportunistic infections, as well as those that can affect people with intact immune systems.  TB may be the most important.  HIV infected individuals are much more susceptible to active TB infections than those who are HIV uninfected.  HIV transcriptional activity and viral loads have been noted to be higher in people with active TB.

Here is a little more detail about these three classes of infection:

A:  Herpesviruses.

There are eight members of the herpesvirus family that can infect humans.   Herpes simplex virus types 1 and 2 (HSV-1, HSV-2) are perhaps the most familiar.  Cytomegalovirus (CMV) and the Epstein-Barr virus (EBV) infect close to 100% of adults.   Varicella-Zoster virus (VZV) causes chicken pox on initial infection and shingles when reactivated. Of the three remaining human herpes viruses HHV-6, HHV-7, and HHV-8, the last is associated with Kaposi’s sarcoma.

With all of the herpes viruses, once infected, individuals carry them for the rest of their lives, usually in a dormant or inactive state.  All can be periodically reactivated with or without symptoms.

Humans and herpes viruses have co-existed for evolutionary periods and are well adapted to each other.   The immune system generally maintains these viruses in a latent sate so that they cause no harm.  Reactivation does occur periodically but is generally limited.  Virtually 100% of adults will carry some viruses of the herpesvirus family, usually in a dormant or latent state.

The impaired immunity characteristic of HIV disease however results in reactivation of herpes virus infections. In progressive HIV disease these viruses become active and through a variety of mechanisms, including their contribution to immune activation, promote the replication of HIV.    Cytomegalovirus (CMV) may be the most important of the herpesviruses that promote HIV disease progression.  It can be part of a positive feedback system in its interactions with HIV.

HIV → latent herpes infections  →active herpes infections → HIV

It is not only through their contributions to immune activation that herpes viruses promote HIV replication.   In addition to the pro-inflammatory cytokines that have this effect, herpes virus gene products can directly activate HIV if a cell is infected with both viruses.  This process, called transactivation works both ways; HIV can also activate herpes viruses.

In addition herpes infections cause a receptor (Fc) to appear on cell surfaces that allows HIV to enter it.  In this way cells that do not possess CD4 molecules can become infected with HIV.   Active CMV infections can also exert a mildly immunosuppressive effect.

Herpesviruses, particularly CMV are singled out because they probably play a significant role in the pathogenesis of HIV disease.  CMV infections are so common that it is hard to find HIV infected individuals who are free from it so that they can be compared to those who are not.   But as early as 1991 this was done with HIV infected haemophiliac patients, when it was noted that those also infected with CMV had a much more rapid progression of their HIV disease[v].

That CMV may play a role was suggested by many very early in the epidemic.  A multifactorial model for the development of this disease published in 1983 before HIV was discovered suggested a major role for CMV and EBV[vi].    The considerable evidence for a role for herpesviruses, particularly for CMV, did not disappear with the discovery of HIV.   The interactions of CMV and other herpes viruses with HIV that have been discovered may now explain their role.

Large studies on the effects of acyclovir on the course of HIV infection have provided compelling evidence that active infection with these viruses can be regarded as part of the disease process for most HIV infected individuals.    Investigators focussed on HSV-2 undoubtedly because it is the most common cause of genital ulcers.   The dose of acyclovir used would also have suppressed  HSV-1, which is even more prevalent than HSV-2 and may be more sensitive to acyclovir.  HIV viral loads and the rate of HIV disease progression were reduced in individuals receiving acyclovir compared to those receiving placebo.  Although genital ulcer recurrences were suppressed by acyclovir, the drug had no effect on the transmission of HIV.

The effects of acyclovir on HIV probably resulted from suppression of active herpes infection.  This is entirely consistent with a model that places HIV and herpesviruses in a positive feedback relationship.

EBV and CMV are much more resistant to acyclovir than HSV-1 and 2.   But it cannot be excluded that this drug did not have some effect in also diminishing reactivations of CMV and EBV.   If samples from the trial have been stored appropriately, this can be looked at.  EBV reactivation patterns are easily recognized, CMV virus isolation is possible and even detection and quantification of activated T lymphocytes would tell us something.

B:  Endemic infections:

These are singled out because of their high prevalence in some parts of the developing world.

These infections affect significant proportions of the population, they tend to be chronic and persist in the absence of treatment.    The specific infections will depend on geography and many are transmitted by insects.   Many of these can also accelerate   HIV disease progression, and some also progress more rapidly in the setting of HIV infection[vii].

C:   Other infections:

On an individual level, some episodic infections can promote HIV replication.   An acute febrile illness may increase HIV viral loads, but this is a transient effect lasting for the duration of the infection.

Most of the serious opportunistic infections occur late in the course of HIV disease, and may promote even further disease progression.

TB deserves special consideration because of its high prevalence in HIV infection.  Susceptibility to TB is increased even at higher CD4 levels. Active TB can then promote further HIV replication thus becoming a partner with HIV in a positive feedback interaction[viii].

A role for immune activation in a positive feedback system:

One way to look at the process of disease acquisition in HIV infection assigns a central role to immune activation.

Immune activation not only results from HIV infection, it can also promote further replication of HIV.

HIV replicates more efficiently in activated immune system cells.  Secondly, the pro-inflammatory cytokines that are associated with an activated immune system   can directly stimulate HIV replication.   Progressive HIV disease and immune activation are therefore components of a positive feedback system in this way.

HIV disease → Immune activation → HIV disease → Immune activation

The process starts with HIV infection, and is promoted by other infections , some of which are activated by HIV infection.

Whatever is driving immune activation is driving HIV disease.

The following diagram illustrates this.

Looking at the course of HIV infection in this way has a number of implications.

Pathogenesis.

In the above diagram the course of HIV disease is represented by a self perpetuating cycle proceeding in a clockwise direction.   In addition to the elements that have positive effects in driving the process, there will also be those that retard the cycle.  This is illustrated in the next diagram which focuses for simplicity on the immunological control of HIV infection and of those infections that add to immune activation.    Of course there are other mitigating factors, for example, genetic factors conferring varying degrees of resistance resulting from receptor polymorphism.

In the diagram, the connection of HIV with CMV and other herpes viruses is probably constant and indicated by a red arrow.   The connection of HIV with endemic and associated infections is indicated by a blue dotted line, because HIV infection does not increase susceptibility to all of them, nor does it accelerate the progression of all.

The positive feedback cycle starts with HIV infection.  At least some of the determinants of the rate of disease progression may be found in the conditions that exist at the time of initial infection that promote or retard the cycle.

There is evidence that the degree of immune activation at the time of seroconversion predicts future disease progression.[ix] [x] It may also be an important determinant of what is called the set point.  This is the point following initial infection with HIV, from which CD4 numbers decline.

The degree of immune activation at seroconversion thus influences the starting CD4 level; the rate of subsequent decline is influenced by the degree of immune activation  in a system where once started, conditions can exist where  immune activation increases with falling CD4 numbers, in a self perpetuating and accelerating fashion.   Whatever the outcome, it will be the balance of positive and negative influences.

In the earliest years there were reports of EBV reactivation preceding HIV seroconversion[xi].

I have not seen any follow up of this interesting report.   It at least suggests that there might even be   situations in which active herpes infections could sometimes promote seroconversion.  They certainly produce signals that can activate HIV transcription from proviral DNA.

Treatment and prevention.

The role of immune activation in driving HIV disease is generally accepted now.   There are sources of immune activation other than HIV and some of these can be controlled.

Attempts to identify and control additional sources of immune activation may be critical in the fight against HIV/AIDS.

Perhaps the most significant benefit in this respect concerns the developing world, where there are so many additional sources of immune activation. Even ascariasis, infestation with the common intestinal round worm is associated with significant immune activation.   Worldwide prevalence is estimated to be about one billion, with 173 million in sub-Saharan Africa.

Many highly prevalent endemic infections can promote HIV replication.  Controlling these are perfectly appropriate targets in the fight against HIV/AIDS, and of course this would independently improve the lives of millions of individuals.

Measures to control endemic infections include traditional public health interventions, such as the provision of sanitation and clean water and the control of insect vectors. Effective drugs are sometimes inexpensive.  Peter Hotez has written an article entitled “Africa’s 32 cent solution to AIDS”.[xii] This refers to the price of Praziquantel , effective in treating  schistosomiasis as a single dose.

The lives of impoverished populations are ravaged and shortened by these infections. Many of these infections also interact with HIV to compound the devastation they cause.  Poverty, multiple endemic infections and HIV are intimately intertwined and in many instances reciprocally affect each other.

Recent and ongoing studies will probably lead to the routine use of drugs that are effective against herpes virus infections.       Trials of valacyclovir to reduce HIV viral loads are in progress. Given the ubiquitous nature of herpes infections, the use of acyclovir as adjunctive therapy might be warranted even in the absence of recurrent herpetic ulcers.  Valacyclovir unfortunately is not yet available as a generic medication.

Unfortunately EBV and CMV are much more resistant to these drugs.   The development of agents less toxic than valgancyclovir is important.   Valgancyclovir has already been shown to reduce immune activation in HIV infected individuals as measured by a reduction in activated CD8 lymphocytes.

In summary it is useful to explicitly recognize the positive feedback interactions between HIV and other infections that can promote its replication, some of which are in turn promoted by HIV.    Control of the AIDS epidemic in Africa must include measures to prevent and treat multiple endemic infections that affect hundreds of millions of individuals.


[i] This is of particular interest to me as I was involved in the discovery of large amounts of interferon in the circulation of people with HIV/AIDS in 1981, the year the disease was a first described.

http://aidsperspective.net/articles/Interferon_Vilcek.pdf

http://sonnabendj.files.wordpress.com/2009/03/aids-inf-31.jpg

[ii] http://aidsperspective.net/articles/Interferon-AZT-1991.pdf Fig 1 shows CD4 counts in relation to serum interferon  . Presented 1986 at the 2nd international aids conference in Paris.

[iii] http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2491901/

[iv] Immune activation and inflammation in HIV-1 infection:  causes and consequences.

V.Appay and D. Sauce

J.Pathol. 2008; 214: 231-241

(This is an important  review)

HIV immunopathogenesis and strategies for intervention.

M. Cadogan and A Dalgleish

Lancet Infectious diseases. 2008: 8: 675-84

[v] http://www3.interscience.wiley.com/journal/119316871/abstract?CRETRY=1&SRETRY=0

[vi] http://aidsperspective.net/articles/NYAS.pdf

[vii] Endemic infections in Africa have everything to do with HIV/AIDS:

http://sonnabendj.files.wordpress.com/2009/06/lawn21.jpg

[viii]

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1905977/

http://www.ncbi.nlm.nih.gov/pubmed/14551885?ordinalpos=1&itool=PPMCLayout.PPMCAppController.PPMCArticlePage.PPMCPubmedRA&linkpos=4

http://www.ncbi.nlm.nih.gov/pubmed/12416451?ordinalpos=1&itool=PPMCLayout.PPMCAppController.PPMCArticlePage.PPMCPubmedRA&linkpos=5

[ix] http://jvi.asm.org/cgi/content/full/81/16/8838?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&fulltext=fig&searchid=1&FIRSTINDEX=1440&resourcetype=HWFIG

[x]

http://bloodjournal.hematologylibrary.org/cgi/content/full/104/4/942

[xi]

http://www3.interscience.wiley.com/journal/119342256/abstract?CRETRY=1&SRETRY=0

[xii] http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0000430

HIV Treatment as Prevention. March 2010

March 4, 2010 Leave a comment

“Treatment as prevention” is in the news again as part of the media coverage of two conferences in California this month where claims were again made that treatment of virtually all HIV infected individuals could bring an end to the AIDS epidemic.

“Research shows that treatment could end the epidemic in thirty years” is typical of the headlines that enthusiastically announced this proposal to test and treat everybody found to be infected. Sadly, most of the reports I saw failed to comment on the huge practical difficulties that will need to be overcome to make such a project feasible. All ignored a probably insuperable ethical obstacle that will have to be confronted, which may well make the project completely unworkable. Added to these difficulties is the lack of agreement on the soundness of the mathematical model on which the proposal is based.

This initiative is also described as “treatment as prevention” although I also saw the term “seek, test and treat” used.

The prevention in “treatment as prevention” results from the reduced ability to transmit HIV that results from treatment with antiviral drugs.

It’s important to note that “treatment as prevention” can refer to two very different situations where infectivity is reduced by treatment. It describes the mathematical model, noted above that was published about a year ago in the Lancet, an influential weekly medical journal, which claims that the AIDS epidemic could be eliminated with regular tests for HIV and the immediate commencement of antiviral treatment of all who are infected. This is the title of the article: “Universal voluntary HIV testing with immediate antiretroviral therapy as a strategy for elimination of HIV transmission: a mathematical model “ (Reuben Granich and colleagues. Lancet 2009 373: 7).

Antiviral therapy according to this model would be given to all infected individuals whether or not the individual needs treatment. It would include lifelong treatment of healthier HIV infected people who have not been shown to benefit from it, such as those with more intact immune systems as well as those fortunate individuals whose disease does not progress. This is the root of the ethical problem; people who themselves are not known to benefit from treatment will be asked to receive it for a societal benefit. The benefits of treatment to such individuals are conjectural but as the drugs are not free from adverse effects, the risks are real. Unlike individuals with more advanced disease where the benefits of treatment vastly outweigh the risks, this cannot be known in the case of healthier HIV infected individuals.

This is very different to the analysis of the reduction in transmission of HIV that results from treating only those HIV infected individuals known to benefit from antiviral drugs. This is also referred to as “treatment as prevention” but unfortunately in none of the reports I saw was the distinction made between treatment only of those who benefit from it and treatment of all infected individuals. These two very different meanings of “treatment as prevention” were almost always conflated by commentators which could quite easily convey a mistaken impression that all HIV infected individuals are known to benefit from treatment.

Treatment must always be voluntary. But a voluntary decision to receive treatment does not mean a great deal if it is uninformed. The decision can most certainly seen to be coerced if misinformation is supplied. HIV infected individuals must be clearly informed about the risks and benefits of the intervention. As already noted, for individuals with more advanced disease, treatment without question provides a net benefit, but this is not known to be the case for HIV infected individuals with more intact immune systems.   There are suggestions that HIV infection may be associated with morbidity resulting from inflammatory reactions.   It is far from firmly established  if this is indeed the case and if it is, whether  it is an inevitable or even common  consequence of HIV infection, or if it can be prevented or treated with antiviral drugs.   It may also prove to be true that, as claimed by some investigators,  the newer antiviral drugs are less toxic than the older ones.  But the full range of their effects, particularly their longer term effects cannot be yet known. HIV disease can manifest in so many different ways that sorting out what is a drug effect from what is an effect of the infection itself may take a long time.

For healthier HIV infected individuals, the benefits of treatment remain conjectural as long as clinical trials have not been completed that are designed to provide a reliable answer to the question of when in the course of HIV disease it is best to start treatment. Quite remarkably, about fifteen years after potent antiviral drugs became available no such trial has been completed.

If a decision about whether or not to receive treatment is fully informed, healthier HIV infected individuals faced with an intervention that is accompanied with very real risks but only conjectural benefits may well choose to remain untreated, at least at that particular time in the course of their disease. The purpose of treatment is to reduce infectivity to others, but many might feel that this can be achieved with greater safety, and even possibly with greater reliability, by the use of condoms.  It should be said though that those researchers who point out the prevention benefits of treatment do not suggest that treatment is an alternative to condoms. On the contrary they recommend that treated individuals continue to use condoms.

Since the objective of treating all infected people is to end the epidemic, this can only be achieved if a large percentage of infected people receive treatment. But faced with a consent form clearly stating what is known about risks and benefits, it is most unlikely that enough healthier HIV infected people will agree to receive treatment. This is but one reason that if a decision to start treatment is properly informed the project is unlikely to enrol enough individuals to achieve its objective. A danger is that treatment of healthier HIV infected people may be claimed to have a net benefit with greater confidence than is warranted with information we presently have.   To succeed, the project also requires a lifetime of adherence to the treatment regimen.  When drugs are taken without confidence that they are of personal benefit, we cannot know how adherence to the regimen will play out.   Failures in this respect will not only diminish the chances that the project will succeed,  they can also result in the emergence of drug resistant strains of HIV which then could limit treatment options when treatment is needed.

There evidently is a belief that all HIV infected individuals, no matter the stage of disease will benefit from treatment. But this remains just that, a belief, as long as there is no firm evidence to support it. The evidence there is that healthier HIV infected individuals would receive a net benefit from treatment is of inferior quality, and therefore remains insecure. It comes from some retrospective observational studies. In such studies medical records are analyzed to compare outcomes in individuals who started treatment earlier with those who started later. Such studies however are beset with interpretative difficulties. Because individuals were not randomly assigned to start treatment early or later, a particular outcome, say improved survival of those starting treatment early, may result from whatever the reasons were that treatment was started at a particular time.

The great benefit of randomly assigning individuals to receive one treatment or another when two are compared is the elimination of interpretative  problems that arise when one or the other course of action is chosen.

The problem of such confounding factors was also discussed in a previous post: http://aidsperspective.net/blog/?p=75

The retrospective analysis most frequently cited in support of an earlier start to antiviral therapy, the NA-ACCORD study is also discussed in that post.

HIV infected individuals and those who advise them surely deserve more reliable evidence to support a decision whether to start or defer treatment than that provided by retrospective observational studies or worse, by mere belief.

Prospective randomized trials remain the best way to achieve this. They minimize bias, and thus misinterpretation, and remain the most reliable way to resolve uncertainty. There is no getting over this. Such trials may be expensive, and last a long time, but in the end, probably more time and money is lost by repeating inconclusive and conflicting retrospective studies. Surely we need to know, and not guess when it is best to start treatment.

START is a large clinical trial designed to provide an answer to the question of whether it is best to start treatment early or to defer it.     Another casualty of the pursuit of treatment as prevention that aims to treat all infected individuals is enrolment in START which may become more difficult. Those promoting treatment of all infected individuals as prevention must evidently feel that they already know the answer to be that an early start is best. How can this belief be reconciled with a respect for evidence based medicine that many of same experts claim to have?

We should rather concentrate our efforts on providing treatment to all HIV positive individuals who are at a stage in their disease where treatment is of unquestionable benefit. The fact that treatment reduces their infectivity to others is an added powerful argument to encourage widespread testing. An additional benefit is that people who know their HIV status are more likely to take steps to prevent infection of others.

The proposal to treat every infected person as a prevention strategy can be criticized on many levels. I have focussed here on the difficulty that arises from including the treatment of individuals not known to benefit from it. This can usefully be linked to support for and encouragement of enrolment in START.

The lack of concern for the ethical problem that arises from treating people not known to benefit from it is puzzling. A headline on the front page of the UK Independent newspaper reporting on the proposal to treat all infected people states: “AIDS: is the end in sight?”  The report quotes the opinion of one scientist that “the problem is that we are using the drugs to save lives, but we are not using them to stop transmission”   This statement  is quite remarkable.   The real problem arises when we administer drugs that can have adverse effects to people for any reason other than for their benefit.   We can only ask individuals to agree to take risks for a societal benefit if we have good reasons to believe that the endeavour has a good chance of success – in this case the grandiose one of ending the epidemic.  For reasons outlined above we cannot provide any confidence that this will be so.  At any rate many may feel that their societal concerns can be more safely met by using condoms, a proven way to reduce transmission of HIV.

I also wrote about this issue for the magazine POZ about a month ago. It can be seen by following this link. http://blogs.poz.com/joseph /archives/2010/02/treatment_of_hiv_dis.html

I also commented on this issue about a year ago. http://aidsperspective.net/blog/?p=152 This post repeats several points that were made then.

HIV Treatment: There is a role for intermittent therapy. July, 2009

From where we are at the moment in our understanding of HIV disease, we have to accept that lifelong treatment will be required for most infected individuals..

The drugs are not free from undesirable effects, they are costly and for many, quality of life is impaired to a greater or lesser extent by taking medications, even a single pill, day after day.

For these reasons it is important to study ways to safely minimize exposure to these necessary drugs.

We have potent tools to fight HIV disease but we still do not know how best to use them to achieve the most favourable antiviral effect, while minimizing toxicity and undesirable effects.

One approach to these objectives – at the moment, perhaps the only viable approach is the study of intermittent therapy as a means to safely reduce exposure to drugs.   This approach will almost definitely not be possible for all HIV infected people needing treatment.  But it may well be possible for most. The cost savings with intermittent therapy could also be substantial.

This important undertaking was dealt a completely unwarranted setback with the publication of the results of the SMART study, in the New England Journal of Medicine in 20061.  SMART is by far the largest study comparing continuous with intermittent therapy.  In this study more people died in the intermittent treatment arm, not only from AIDS associated events but all cause mortality was increased, including more deaths from cardiovascular disease and from some cancers not previously associated with AIDS.

The negative effect of SMART on the study of intermittent treatment continues.   In addition, because of the association of an increased number of deaths with intermittent treatment from cardiovascular disease and other conditions not related to HIV disease, the SMART study results have been interpreted by some to indicate that HIV disease includes a much wider spectrum of clinical manifestations than previously thought.  The most favoured explanation for how HIV infection causes heart disease and some other conditions is that they are a consequence of inflammation induced by infection with this virus.

For a number of reasons, the conclusion that, as a generalization, intermittent therapy is associated with a worse outcome compared to continuous therapy is completely without justification.  The original SMART study report omitted information that brings this conclusion into question; this has been alluded to in a previous post.

SMART studied just one particular strategy of CD4 guided intermittent therapy, in a population where  multiple non HIV related diseases were overrepresented in US sites, where almost all deaths occurred (79 out of a total of 85 deaths). These conditions included hepatitis B and C,  hypertension, and a previous  history of heart disease   Even setting aside interpretative difficulties concerning this particular study, one can say no more than that the particular strategy of treatment interruption used in SMART, in the population studied, indicated a worse outcome in those randomized to receive intermittent therapy.   That’s all.  The generalizations made about the danger of intermittent treatment were completely unjustified, although enthusiastically endorsed by many community commentators, and repeatedly stressed in educational  literature addressed to physicians.

Inappropriate generalizations of course apply to other studies of treatment interruptions, which used different criteria for interrupting therapy. All the other studies were smaller than SMART and had different follow up times.  But in all of them the excess mortality observed in SMART was not seen, although in some, morbidity, particularly bacterial infections, was more frequent with intermittent treatment.

Some examples are the Trivacan study2 which was conducted in a different population using different interruption criteria. There was an excess of bacterial infections in those receiving intermittent therapy but not the excess of deaths noted in SMART.  The Staccato study3,  using a different interruption strategy also did not show the excess mortality seen in SMART in the treatment interruption group.

The LOTTI study4 concluded that the continuous and intermittent therapy groups could be considered equivalent.  Actually, in complete contradistinction to the SMART results, in this study, cardiovascular disease was actually worse in the continuous therapy group (controls) compared to those receiving intermittent therapy (STI group).  Although pneumonia was more frequent in the STI group.    Here is a sentence from the author’s abstract.

A higher proportion of patients in the STI arm were diagnosed with pneumonia (P 0.037), whereas clinical events influencing the cardiovascular risk of patients were significantly (P<0.0001) more frequent among controls”.

The finding regarding cardiovascular disease is particularly relevant.

Much has been made of the increases in cardiovascular disease seen in the intermittent treatment group in the SMART study.  It is now considered by some that HIV infection per se constitutes a risk for heart disease and this, as noted, is attributed to HIV induced inflammation.   There are even studies now that look at arterial wall thickening as a measure of atherosclerosis and find this to be increased in untreated HIV infected people.  So this needs to be studied.  But in terms of cardiovascular clinical events, LOTTI tells us these are more frequent in people receiving continuous therapy compared to those receiving intermittent treatment.

Despite evidence to the contrary some “experts” still tell physicians to avoid treatment interruptions in order to protect patient’s cardiovascular health!!

There are even sponsored courses for physicians for whom CME credit can be earned where instruction is provided to not interrupt treatment precisely because this will increase the risk of heart disease, as well as other problems.

I was shown an invitation to physicians to a free course offered by a distinguished academic institution.   Among the descriptions of what those attending the course will learn to do is the following:

“Describe, discuss and apply the data from the SMART study on CHD  (coronary heart disease)  risk associated with ARV treatment interruption and be able to integrate these data into ARV treatment plans and algorithms for HIV-positive patients”

What is one to make of this in the light of the LOTTI observations?

This absurdity can only be possible because there is a selective reporting of information to HIV infected people, their advocates and to physicians who are not able to look at all the literature.   As a consequence almost none of the web sites devoted to conveying information to patients and their advocates have even mentioned the LOTTI study.

As far as cardiovascular disease is concerned those of us who took care of HIV infected patients in the 1980s before effective treatments were available will have observed that people with AIDS characteristically had huge elevations in their serum triglycerides.  They also characteristically had low levels of HDL cholesterol (and of total cholesterol).  I helped a resident in a hospital where I once worked to prepare a report on HDL levels in HIV infected patients before HAART was available.  We used my patient records from the 1980s and were able to clearly show that as the disease progressed over time, HDL levels decreased.    There was, not surprisingly,  a correlation between falling HDL levels and falling CD4 counts – data which I never published, but probably can still find.

So, there may indeed be something in the connection between untreated HIV disease and heart disease.  In the early days possibly our patients did not survive long enough to manifest any clinical manifestation of heart disease.   Increased triglycerides are an independent risk factor for coronary heart disease.  There even was a possible mechanism for this that was known in those days that could account for this.

Untreated individuals with more advanced disease have high serum levels of alpha interferon (also increased levels of gamma interferon) and TNF alpha, and both of these cytokines can inhibit an enzyme called lipoprotein lipase that then results in the lipid changes noted.  Such changes have been seen in people with hepatitis C treated with recombinant interferon.

So, why is the failure of just one form of intermittent therapy used to categorically condemn the practice in principle?   There are numerous different ways in which intermittent therapy can be structured.

The discouragement of the study of intermittent therapy is even more peculiar in view of the different outcomes of other, albeit,  studies smaller  than SMART

Perhaps a clue is to be found in a sentence in the LOTTI study report.

Here it is:

“The mean daily therapeutic cost was 20.29 euros  for controls and dropped to 9.07 euros  in the STI arm (P<0.0001)”.

This more or less translates into a 50% reduction in drug sales to people receiving intermittent treatment according to the LOTTI protocol.

Taking other studies of intermittent therapy into account, and considering some problems associated with SMART, I believe that one can say with a resounding affirmative that, in principle , intermittent therapy can be safe. Not for all, and maybe not for all of the time, but probably for many HIV infected individuals with over 350 CD4 lymphocytes who need treatment (who such individuals may be is also a controversial issue particularly regarding individuals with over 350 CD4 lymphocytes),   some form of intermittent therapy will probably be demonstrated to be safe.  For individuals with at least 700 CD4 lymphocytes, this is already the case.

Many of my patients wanted to take “treatment holidays” as they were once called; some from time to time, and others on some regular basis.  I have always believed that we need to find ways where we can safely minimize drug exposure so I was supportive of their wishes, as long as some conditions were met and we had the means to monitor viral load and CD4 counts.   This desire for treatment interruptions  was obviously  true not only among my patients but it seemed quite common in New York City to hear of individuals who were receiving some form of intermittent treatment, and this must also be the case elsewhere.

Of course for individuals with CD4 counts below 200, this was not a good idea.   Whatever we did, we knew that we needed to keep the CD4 count above this level. So, for patients with higher CD4 counts a variety of strategies were used.

There will be many anecdotes accumulated over the years of such experiences of intermittent treatment.   I need to stress that these are just anecdotes and most definitely not formal studies.  As such they can only lead to hypotheses on which studies can be based.

It would be foolhardy for HIV infected individuals to interrupt treatment without the advice and close supervision of an experienced physician. I have seen too many individuals who have come to harm by stopping their medications completely on their own, without supervision and not even informing their physicians that treatment was stopped.  This at least indicates that there is such a thing as “pill fatigue”, something we cannot ignore.

Of my patients who interrupted treatment none have come to harm.  There was no established protocol to guide us and strategies used took patient preference into account.    An effective antiviral combination, one that has produced sustained suppression, at least as indicated by an undetectable viral load should work again if stopped and re started later. There may be some theoretical difficulty in abruptly stopping antivirals that are slowly eliminated without additional temporary cover.   As a result, in certain patients some form of episodic treatment was used, that is periods on treatment alternating with periods off treatment.  This approach is now generally considered to be unsafe and CD4 guided strategies are studied.   But numerous anecdotes as well as earlier studies of episodic treatment indicate that this approach can be viable in some situations, and I believe should be further studied.

In an editorial in the journal reporting the LOTTI study Bernard Herschel and Timothy Flanagan state.

“Many of our patients with high CD4 cell counts want to

stop treatment. The LOTTI study does not justify a

recommendation in that regard, but it does give clinicians

useful information that it is probably safe to stop

treatment within the limits of CD4 cell counts of

LOTTI. Continued vigilance is needed so that excellent

adherence is maintained when patients are on HAART

to prevent the emergence of resistance.

The LOTTI study adds important information to the

continued question of whether there is a role for

interrupted therapy. Further study is justified, particularly

with newer combination therapies, which may well

have less toxicity and therefore shift the balance towards

continuous treatment. Clinicians will welcome the

information from LOTTI because it can allay some of

the concerns regarding the safety of treatment interruptions

at high CD4 cell counts”.

In the LOTTI trial, treatment was restarted when the CD4 count dropped  to 350 and stopped at a CD4 count of  700.  So within these limits we have some reassurance of safety.

So, further study is absolutely warranted.

In the LOTTI study, participants had to have a CD4 count of 700.

What about individuals who have had  undetectable viral loads for six months (as in LOTTI) but whose CD4 count has remained stable at 500, or 450 or some number lower than 700?    Studies with different CD4 criteria should continue and not be deterred by the SMART results.

I have written about the need to work on ways to individualize therapy to take individual rates of disease progression as well as other individual characteristics into consideration.   That is to get away from the prevailing  one size fits all approach to therapy,  mainly using a snapshot of just one or two parameters,  the CD4 count and viral load to guide one, without considering the rate of change in  CD4 numbers.

In the same way, studies to individualize intermittent treatment interupptions in those for whom it is possible should be considered.   As noted, if an antiviral regimen is effective in fully suppressing replication – at least to the extent indicated by an undetectable viral load, there is absolutely no reason why it should not be effective again if stopped. There may be some consideration needed regarding how to stop with some drugs that are eliminated very slowly.   (Of course an individual may be super infected with a drug resistant variant).

It is likely that some form of episodic treatment may be effective in selected individuals.   That is, periods on treatment alternating with periods off treatment.   Because of its flexibility it is probably best suited to individualization.

As mentioned, this approach has been thought to be more dangerous than a CD4 guided strategy.  But this approach appeared to be effective in earlier studies but they have not had long periods of follow up5.   But other similar studies have shown a high rate of viral rebound6.

However, the fact that there has been a successful study and the many anecdotes of successful episodic types of intermittent therapy provide encouragement that it is worthwhile to continue to study such an approach.

It certainly is possible to study the characteristics of those individuals in whom such an approach has proven to be successful.

I conclude with a few more comments on the SMART study with a possible explanation for the huge discrepancy in the number of deaths in US sites, 79, compared to only 6 in non US sites.   At least there is a very clear reason why the results observed in this study should not be generalized to all HIV infected individuals.

The study was conducted in US sites on what appear to have been a group of individuals in whom disorders unrelated to HIV were overrepresented.  As mentioned earlier, these disorders include diabetes, hepatitis B and C, high blood pressure and a history of heart disease.

Look at this table, which has been copied from a report on a SMART follow on study of inflammation in trial participants7.

This table shows characteristics of individuals who died compared to those who did not.

Kuller 2

The 85 people who died are represented in the third column, and their characteristics have been compared to those of two individuals who did not die (controls).

It can be seen that of the people who died, compared to those who did not, 11.8%  vs  4.7% had a history of heart disease (p=0.04);  45.9% vs 24.1%  were co infected with Hepatitis B or C  (p = 0.0008); 57.6% vs 31.8% were current smokers (p = 0.0001); 25.9% vs 14.7% were diabetic (p = 0.03); 38.8% vs 25.3% were taking medications for high blood pressure (p = 0.02).

Thus the people who died in the SMART study tended to be sick with non HIV related conditions.  64% of them were in the treatment interruption group so this tells us that individuals who already have more traditional risk factors may increase their risk of death by interrupting treatment according to the schedule defined in SMART.

But there is another remarkable figure in this table.  92.9 % of those who died were participants in US sites!  I have already written about this – that of the 85 deaths in SMART, 79 occurred in US sites with 55% of participants, and only 6 people died in sites outside the US where 45% of individuals were enrolled.

Despite what some experts incessantly tell us, SMART cannot justifiably be used to conclude that intermittent treatment is dangerous, in principle,  for all HIV infected individuals, particularly with additional information that for some reason, has only been made available less than a year ago.

The original report of the SMART study in the New England Journal of medicine in 2006 reported the baseline characteristics of participants.  All of these baseline characteristics, including co morbidities and traditional risk factors for heart disease such as hypertension and smoking were about the same in both treatment groups – that is, in those receiving continuous therapy and those on the treatment interruption arm.   However the distribution of these characteristics in those who died was not reported in this publication.  We had to wait until October 2008 to learn that those who died already had more multiple health problems unrelated to HIV infection.

I missed seeing this 2008 publication.  It seems that most who saw it had little to say.  But the strange distribution of deaths was brought to attention again with comments in the Lancet Infectious Disease in April of this year8.   I did not miss it this time, and have already written about it.

Because of the deleterious and unwarranted influence of SMART in discouraging the study of intermittent therapy, I thought it was absolutely important to make this information as widely known as possible.   Without further explanation, these results indicating the greater extent of co morbidities and traditional risk factors among those who died bring the often repeated conclusion  that the SMART study indicates that treatment interruptions are unsafe for all,  into question.

To my great surprise, despite my best efforts to disseminate this information on the strange distribution of deaths during the study, there was almost no expression of interest from the many individuals I communicated with.

This lack of interest is really puzzling.

Despite what might be considered to be an inappropriate generalization of the results, particularly regarding the relationship of HIV infection to deaths from causes unrelated to HIV infection the SMART study was a massive undertaking and its completion should be seen as a triumph.

Organizing such a huge endeavour that was dispersed so widely is a tremendous achievement.  There are sub studies and follow on studies that continue and will advance our understanding of HIV disease.

We know with some security from SMART that HIV infected individuals with Hepatitis B and C,   hypertension, and a past history of heart disease and some other associated health problems would increase their risk of death by interrupting treatment for HIV according to the strategy used in SMART.

For otherwise healthy HIV infected individuals it is likely that for some, unfortunately not for all,   a form of treatment interruption will be demonstrated to be safe.  This can already be said for those meeting the conditions of the participants in the LOTTI trial.

The original report of the SMART study was published in the New England Journal of medicine in 2006.

http://content.nejm.org/cgi/content/full/355/22/2283

———————————————————————————————————————–

Refs

1:    New England Journal of medicine    2006  355:2283-2296

2:    Trivacan(ANRS 1269)    Lancet  2006  367:1981-1989

3:    Staccato                           Lancet 2006   368: 459-465

4:    LOTTI                                AIDS     2009   23:799-807

5:     Proceedings National Academy of Sciences   2001   98: 15161-6

6:      AIDS  2003    17:2257-2258

7:      Kuller et al.   PLoS  Oct. 2008   5(10): e203

8:      The Lancet Infectious Diseases  2009 Vol 9 Issue 5 268-9

Despite the SMART study there is a role for intermittent therapy. July, 2009

From where we are at the moment in our understanding of HIV disease, we have to accept that lifelong treatment will be required for most infected individuals..

The drugs are not free from undesirable effects, they are costly and for many, quality of life is impaired to a greater or lesser extent by taking medications, even a single pill, day after day.

For these reasons it is important to study ways to safely minimize exposure to these necessary drugs.

We have potent tools to fight HIV disease but we still do not know how best to use them to achieve the most favourable antiviral effect, while minimizing toxicity and undesirable effects.

One approach to these objectives – at the moment, perhaps the only viable approach is the study of intermittent therapy as a means to safely reduce exposure to drugs.   This approach will almost definitely not be possible for all HIV infected people needing treatment.  But it may well be possible for most. The cost savings with intermittent therapy could also be substantial.

This important undertaking was dealt a completely unwarranted setback with the publication of the results of the SMART study, in the New England Journal of Medicine in 20061.  SMART is by far the largest study comparing continuous with intermittent therapy.  In this study more people died in the intermittent treatment arm, not only from AIDS associated events but all cause mortality was increased, including more deaths from cardiovascular disease and from some cancers not previously associated with AIDS.

The negative effect of SMART on the study of intermittent treatment continues.   In addition, because of the association of an increased number of deaths with intermittent treatment from cardiovascular disease and other conditions not related to HIV disease, the SMART study results have been interpreted by some to indicate that HIV disease includes a much wider spectrum of clinical manifestations than previously thought.  The most favoured, and almost certainly correct explanation for how HIV infection causes heart disease and some other conditions is that they are a consequence of inflammation induced by infection with this virus.

For a number of reasons, the conclusion that, as a generalization, intermittent therapy is associated with a worse outcome compared to continuous therapy is completely without justification.  The original SMART study report omitted information that brings this conclusion into question; this has been alluded to in a previous post.    Almost all the deaths in the study occurred at US sites, where in contrast to non-US sites multiple co-morbidities were over represented.  As seen in the table below these co morbidities included, among other conditions,  hepatitis B and C, a history of heart disease and  diabetes.  There were even significantly more smokers among those enrolled at US sites.  How can one extrapolate interpretations of observations made in such  individuals  to HIV infected  populations free from these co-morbidities?

SMART studied just one particular strategy of CD4 guided intermittent therapy, in a population where  multiple non HIV related diseases were overrepresented in US sites, where almost all deaths occurred (79 out of a total of 85 deaths). These conditions included hepatitis B and C,  hypertension, and a previous  history of heart disease   Even setting aside interpretative difficulties concerning this particular study, one can say no more than that the particular strategy of treatment interruption used in SMART, in the population studied, indicated a worse outcome in those randomized to receive intermittent therapy.   That’s all.  The generalizations made about the danger of intermittent treatment were completely unjustified, although enthusiastically endorsed by many community commentators, and repeatedly stressed in educational  literature addressed to physicians.

Inappropriate generalizations of course apply to other studies of treatment interruptions, which used different criteria for interrupting therapy. All the other studies were smaller than SMART and had different follow up times.  But in all of them the excess mortality observed in SMART was not seen, although in some, morbidity, particularly bacterial infections, was more frequent with intermittent treatment.

Some examples are the Trivacan study2 which was conducted in a different population using different interruption criteria. There was an excess of bacterial infections in those receiving intermittent therapy but not the excess of deaths noted in SMART.  The Staccato study3,  using a different interruption strategy also did not show the excess mortality seen in SMART in the treatment interruption group.

The LOTTI study4 concluded that the continuous and intermittent therapy groups could be considered equivalent.  Actually, in complete contradistinction to the SMART results, in this study, cardiovascular disease was actually worse in the continuous therapy group (controls) compared to those receiving intermittent therapy (STI group).  Although pneumonia was more frequent in the STI group.    Here is a sentence from the author’s abstract.

A higher proportion of patients in the STI arm were diagnosed with pneumonia (P 0.037), whereas clinical events influencing the cardiovascular risk of patients were significantly (P<0.0001) more frequent among controls”.

The finding regarding cardiovascular disease is particularly relevant.

Much has been made of the increases in cardiovascular disease seen in the intermittent treatment group in the SMART study.  It is now considered by some that HIV infection per se constitutes a risk for heart disease and this, as noted, is attributed to HIV induced inflammation.   There are even studies now that look at arterial wall thickening as a measure of atherosclerosis and find this to be increased in untreated HIV infected people.  So this needs to be studied.  But in terms of cardiovascular clinical events, LOTTI tells us these are more frequent in people receiving continuous therapy compared to those receiving intermittent treatment.

Despite evidence to the contrary some “experts” still tell physicians to avoid treatment interruptions in order to protect patient’s cardiovascular health!!

There are even sponsored courses for physicians for whom CME credit can be earned where instruction is provided to not interrupt treatment precisely because this will increase the risk of heart disease, as well as other problems.

I was shown an invitation to physicians to a free course offered by a distinguished academic institution.   Among the descriptions of what those attending the course will learn to do is the following:

“Describe, discuss and apply the data from the SMART study on CHD  (coronary heart disease)  risk associated with ARV treatment interruption and be able to integrate these data into ARV treatment plans and algorithms for HIV-positive patients”

What is one to make of this in the light of the LOTTI observations?

This absurdity can only be possible because there is a selective reporting of information to HIV infected people, their advocates and to physicians who are not able to look at all the literature.   As a consequence almost none of the web sites devoted to conveying information to patients and their advocates have even mentioned the LOTTI study.

As far as cardiovascular disease is concerned those of us who took care of HIV infected patients in the 1980s before effective treatments were available will have observed that people with AIDS characteristically had huge elevations in their serum triglycerides.  They also characteristically had low levels of HDL cholesterol (and of total cholesterol).  I helped a resident in a hospital where I once worked to prepare a report on HDL levels in HIV infected patients before HAART was available.  We used my patient records from the 1980s and were able to clearly show that as the disease progressed over time, HDL levels decreased.    There was, not surprisingly,  a correlation between falling HDL levels and falling CD4 counts – data which I never published, but probably can still find.

So, there may indeed be something in the connection between untreated HIV disease and heart disease.  In the early days possibly our patients did not survive long enough to manifest any clinical manifestation of heart disease.   Increased triglycerides are an independent risk factor for coronary heart disease.  There even was a possible mechanism for this that was known in those days that could account for this.

Untreated individuals with more advanced disease have high serum levels of alpha interferon (also increased levels of gamma interferon) and TNF alpha, and both of these cytokines can inhibit an enzyme called lipoprotein lipase that then results in the lipid changes noted.  Such changes have been seen in people with hepatitis C treated with recombinant interferon.

So, why is the failure of just one form of intermittent therapy used to categorically condemn the practice in principle?   There are numerous different ways in which intermittent therapy can be structured.

The discouragement of the study of intermittent therapy is even more peculiar in view of the different outcomes of other, albeit,  studies smaller  than SMART

Perhaps a clue is to be found in a sentence in the LOTTI study report.

Here it is:

“The mean daily therapeutic cost was 20.29 euros  for controls and dropped to 9.07 euros  in the STI arm (P<0.0001)”.

This more or less translates into a 50% reduction in drug sales to people receiving intermittent treatment according to the LOTTI protocol.

Taking other studies of intermittent therapy into account, and considering some problems associated with SMART, I believe that one can say with a resounding affirmative that, in principle , intermittent therapy can be safe. Not for all, and maybe not for all of the time, but probably for many HIV infected individuals with over 350 CD4 lymphocytes who need treatment (who such individuals may be is also a controversial issue particularly regarding individuals with over 350 CD4 lymphocytes),   some form of intermittent therapy will probably be demonstrated to be safe.  For individuals with at least 700 CD4 lymphocytes, this is already the case.

Many of my patients wanted to take “treatment holidays” as they were once called; some from time to time, and others on some regular basis.  I have always believed that we need to find ways where we can safely minimize drug exposure so I was supportive of their wishes, as long as some conditions were met and we had the means to monitor viral load and CD4 counts.   This desire for treatment interruptions  was obviously  true not only among my patients but it seemed quite common in New York City to hear of individuals who were receiving some form of intermittent treatment, and this must also be the case elsewhere.

Of course for individuals with CD4 counts below 200, this was not a good idea.   Whatever we did, we knew that we needed to keep the CD4 count above this level. So, for patients with higher CD4 counts a variety of strategies were used.

There will be many anecdotes accumulated over the years of such experiences of intermittent treatment.   I need to stress that these are just anecdotes and most definitely not formal studies.  As such they can only lead to hypotheses on which studies can be based.

It would be foolhardy for HIV infected individuals to interrupt treatment without the advice and close supervision of an experienced physician. I have seen too many individuals who have come to harm by stopping their medications completely on their own, without supervision and not even informing their physicians that treatment was stopped.  This at least indicates that there is such a thing as “pill fatigue”, something we cannot ignore.

Of my patients who interrupted treatment none have come to harm.  There was no established protocol to guide us and strategies used took patient preference into account.    An effective antiviral combination, one that has produced sustained suppression, at least as indicated by an undetectable viral load should work again if stopped and re started later. There may be some theoretical difficulty in abruptly stopping antivirals that are slowly eliminated without additional temporary cover.   As a result, in certain patients some form of episodic treatment was used, that is periods on treatment alternating with periods off treatment.  This approach is now generally considered to be unsafe and CD4 guided strategies are studied.   But numerous anecdotes as well as earlier studies of episodic treatment indicate that this approach can be viable in some situations, and I believe should be further studied.

In an editorial in the journal reporting the LOTTI study Bernard Herschel and Timothy Flanagan state.

“Many of our patients with high CD4 cell counts want to

stop treatment. The LOTTI study does not justify a

recommendation in that regard, but it does give clinicians

useful information that it is probably safe to stop

treatment within the limits of CD4 cell counts of

LOTTI. Continued vigilance is needed so that excellent

adherence is maintained when patients are on HAART

to prevent the emergence of resistance.

The LOTTI study adds important information to the

continued question of whether there is a role for

interrupted therapy. Further study is justified, particularly

with newer combination therapies, which may well

have less toxicity and therefore shift the balance towards

continuous treatment. Clinicians will welcome the

information from LOTTI because it can allay some of

the concerns regarding the safety of treatment interruptions

at high CD4 cell counts”.

In the LOTTI trial, treatment was restarted when the CD4 count dropped  to 350 and stopped at a CD4 count of  700.  So within these limits we have some reassurance of safety.

So, further study is absolutely warranted.

In the LOTTI study, participants had to have a CD4 count of 700.

What about individuals who have had  undetectable viral loads for six months (as in LOTTI) but whose CD4 count has remained stable at 500, or 450 or some number lower than 700?    Studies with different CD4 criteria should continue and not be deterred by the SMART results.

I have written about the need to work on ways to individualize therapy to take individual rates of disease progression as well as other individual characteristics into consideration.   That is to get away from the prevailing  one size fits all approach to therapy,  mainly using a snapshot of just one or two parameters,  the CD4 count and viral load to guide one, without considering the rate of change in  CD4 numbers.

In the same way, studies to individualize intermittent treatment interupptions in those for whom it is possible should be considered.   As noted, if an antiviral regimen is effective in fully suppressing replication – at least to the extent indicated by an undetectable viral load, there is absolutely no reason why it should not be effective again if stopped. There may be some consideration needed regarding how to stop with some drugs that are eliminated very slowly.   (Of course an individual may be super infected with a drug resistant variant).

It is likely that some form of episodic treatment may be effective in selected individuals.   That is, periods on treatment alternating with periods off treatment.   Because of its flexibility it is probably best suited to individualization.

As mentioned, this approach has been thought to be more dangerous than a CD4 guided strategy.  But this approach appeared to be effective in earlier studies but they have not had long periods of follow up5.   But other similar studies have shown a high rate of viral rebound6.

However, the fact that there has been a successful study and the many anecdotes of successful episodic types of intermittent therapy provide encouragement that it is worthwhile to continue to study such an approach.

It certainly is possible to study the characteristics of those individuals in whom such an approach has proven to be successful.

I conclude with a few more comments on the SMART study with a possible explanation for the huge discrepancy in the number of deaths in US sites, 79, compared to only 6 in non US sites.   At least there is a very clear reason why the results observed in this study should not be generalized to all HIV infected individuals.

The study was conducted in US sites on what appear to have been a group of individuals in whom disorders unrelated to HIV were overrepresented.  As mentioned earlier, these disorders include diabetes, hepatitis B and C, high blood pressure and a history of heart disease.

Look at this table, which has been copied from a report on a SMART follow on study of inflammation in trial participants7.

This table shows characteristics of individuals who died compared to those who did not.

Kuller 2

The 85 people who died are represented in the third column, and their characteristics have been compared to those of two individuals who did not die (controls).

It can be seen that of the people who died, compared to those who did not, 11.8%  vs  4.7% had a history of heart disease (p=0.04);  45.9% vs 24.1%  were co infected with Hepatitis B or C  (p = 0.0008); 57.6% vs 31.8% were current smokers (p = 0.0001); 25.9% vs 14.7% were diabetic (p = 0.03); 38.8% vs 25.3% were taking medications for high blood pressure (p = 0.02).

Thus the people who died in the SMART study tended to be sick with non HIV related conditions.  64% of them were in the treatment interruption group so this tells us that individuals who already have more traditional risk factors may increase their risk of death by interrupting treatment according to the schedule defined in SMART.

But there is another remarkable figure in this table.  92.9 % of those who died were participants in US sites!  I have already written about this – that of the 85 deaths in SMART, 79 occurred in US sites with 55% of participants, and only 6 people died in sites outside the US where 45% of individuals were enrolled.

Despite what some experts incessantly tell us, SMART cannot justifiably be used to conclude that intermittent treatment is dangerous, in principle,  for all HIV infected individuals, particularly with additional information that for some reason, has only been made available less than a year ago.

The original report of the SMART study in the New England Journal of medicine in 2006 reported the baseline characteristics of participants.  All of these baseline characteristics, including co morbidities and traditional risk factors for heart disease such as hypertension and smoking were about the same in both treatment groups – that is, in those receiving continuous therapy and those on the treatment interruption arm.   However the distribution of these characteristics in those who died was not reported in this publication.  We had to wait until October 2008 to learn that those who died already had more multiple health problems unrelated to HIV infection.

I missed seeing this 2008 publication.  It seems that most who saw it had little to say.  But the strange distribution of deaths was brought to attention again with comments in the Lancet Infectious Disease in April of this year8.   I did not miss it this time, and have already written about it.

Because of the deleterious and unwarranted influence of SMART in discouraging the study of intermittent therapy, I thought it was absolutely important to make this information as widely known as possible.   Without further explanation, these results indicating the greater extent of co morbidities and traditional risk factors among those who died bring the often repeated conclusion  that the SMART study indicates that treatment interruptions are unsafe for all,  into question.

To my great surprise, despite my best efforts to disseminate this information on the strange distribution of deaths during the study, there was almost no expression of interest from the many individuals I communicated with.

This lack of interest is really puzzling.

Despite what might be considered to be an inappropriate generalization of the results, particularly regarding the relationship of HIV infection to deaths from causes unrelated to HIV infection the SMART study was a massive undertaking and its completion should be seen as a triumph.

Organizing such a huge endeavour that was dispersed so widely is a tremendous achievement.  There are sub studies and follow on studies that continue and will advance our understanding of HIV disease.

We know with some security from SMART that HIV infected individuals with Hepatitis B and C,   hypertension, and a past history of heart disease and some other associated health problems would increase their risk of death by interrupting treatment for HIV according to the strategy used in SMART.

For otherwise healthy HIV infected individuals it is likely that for some, unfortunately not for all,   a form of treatment interruption will be demonstrated to be safe.  This can already be said for those meeting the conditions of the participants in the LOTTI trial.

The original report of the SMART study was published in the New England Journal of medicine in 2006.

http://content.nejm.org/cgi/content/full/355/22/2283

———————————————————————————————————————–

Refs

1:    New England Journal of medicine    2006  355:2283-2296

2:    Trivacan(ANRS 1269)    Lancet  2006  367:1981-1989

3:    Staccato                           Lancet 2006   368: 459-465

4:    LOTTI                                AIDS     2009   23:799-807

5:     Proceedings National Academy of Sciences   2001   98: 15161-6

6:      AIDS  2003    17:2257-2258

7:      Kuller et al.   PLoS  Oct. 2008   5(10): e203

8:      The Lancet Infectious Diseases  2009 Vol 9 Issue 5 268-9

Endemic Infections in Africa have everything to do with HIV/AIDS and are a long neglected therapeutic target.

June 6, 2009 1 comment

An article with the striking title “Africa’s 32 Cents Solution for HIV/AIDS” was just published in PLoS Neglected Tropical Diseases.  It can be seen here:

http://www.plosntds.org/article/info%3Adoi%2F10.1371%2Fjournal.pntd.0000430

This dramatic title refers to the cost of treatment of schistosomiasis with praziquantal.

Schistosomiasis is an infection caused by parasitic worms, or helminths., of the genus  Schistosoma.    Most of the 200 million cases of schistosomiasis in the world occur in Africa.

The species, Schistosoma haematobium is estimated to infect about 112 million people in sub Saharan Africa.  So its high prevalence puts it in the same class as that of TB, malaria and HIV.  It is responsible for a huge burden of morbidity particularly in children and young adults.

S. haematobium  has a complicated life cycle, some of which takes place in snails.  People are infected by organisms released by snails living in fresh water. These organisms can penetrate the skin of any body part that is immersed in snail infested water.  S. haematobium affects the urinary tract.  The disease it causes is commonly called bilharzia.

I was very conscious of its danger as a child growing up in Zimbabwe, with signs at several small lakes around Bulawayo warning one not to swim in them because of the danger of bilharzia.

Peter Hotez and colleagues article is a welcome addition to the already substantial literature that strongly suggests that many endemic infections, not only with helminths, but also with bacteria, protozoa and viruses can increase the transmission of HIV and most probably  have a detrimental effect on the course of HIV infection.

This paper concentrates on the local effects of S.haematobium on the female genital tract , where lesions caused by  schistosome egg deposition result in mucosal patches, that can bleed during sexual intercourse. The authors state “Presumably, the schistosome egg granulomas produce genital lesions and mucosal barrier breakdown to facilitate HIV viral entry” and go on to compare this to the process by which herpes simplex ulcers increase susceptibility to HIV.

This does seem obvious – there is a mucosal break, so HIV has a way in.

In fact in the case of herpes simplex, this seemingly obvious connection is probably not correct.   The large Partners in Prevention study, recently completed, found that acyclovir, a drug effective in treating herpes does not reduce the risk of HIV transmission.  The drug however was associated with a reduction in the number of recurrences of herpetic ulcerations, and significantly slowed HIV disease progression.  I have written about this in another post.

As with herpes simplex, it is possible that systemic effects of schistosomiasis, may be much more significant, or at least as significant, as local effects in enhancing the transmission of HIV.    Of course, both local and systemic effects may play a role in enhancing HIV transmission.  The systemic effects include an impairment of virus specific immune responses; immune activation may also increase susceptibility to HIV and promote its replication.

The influence of associated infections on the infectivity of HIV extends far beyond that of schistosomiasis.  Peter Hotez  (the lead author of the above article) has done a great service by bringing attention to a number of devastating neglected tropical diseases.  This important article can be seen in the Lancet of May 2nd, 2009, (Lancet 2009 373;1570-1575).

The title of the article is:

“Rescuing the bottom billion through control of neglected tropical diseases”

By Peter J Hotez, Alan Fenwick, Lorenzo Savioli and David Molyneux

I have copied this table from the above article:

tropical

These are incredibly huge numbers.

Many of these infections occur in children and young adults and not only  have an impact on life expectancy, but significantly are the cause of chronic debility particularly in young people.

Some also have an activating effect on HIV replication by several mechanisms, some of which  have been understood for well over ten years.  The resulting acceleration of HIV infection,  by  increasing  HIV viral loads,  as well as by other mechanisms increases the transmission of this virus.

The health of hundreds of millions of individuals could be improved by efforts to prevent and treat these infections.  These infections are also appropriate therapeutic targets in the fight against HIV/AIDS.

Despite a great deal of evidence for the interaction of multiple bacterial, viral, protozoal and helminthic infections and HIV,  this association has been inexplicably neglected in providing  additional approaches to controlling the epidemic..

I had what might be described as a  misfortune to have been a member of President Mbeki’s panel on AIDS, an almost surreal experience I should write about.  The following is an excerpt from something I wrote for this panel almost 10 years ago:

“The crucial difference in Africa, as opposed to the US, is the high prevalence of associated infections. These include STDs, TB, malaria and other protozoal infections, helminthic and bacterial  infections. Such infections would supply sustained signals, such as IL-1  IL-6 and TNF, known to activate HIV.  Some can also upregulate the expression of chemokine co receptors required for HIV entry.  Some of these infections are  somewhat immunosuppressive themselves, an effect contributed to by the secretion of IL-10.37 Sexual transmission of HIV is also known to be facilitated by a high viral burden.38 This would also be the consequence of the HIV activating effect of frequent associated infections in Africa.”

This was almost 10 years ago, and since then literature has continued to accumulate documenting the detrimental interactions between HIV and multiple infectious agents.

About two years ago I made a presentation at the Prevention Research Center at Berkeley, trying to understand why endemic diseases had been so neglected in our attempts to control AIDS, particularly in Africa.  I thought that part of the problem was poor interdisciplinary communication and understanding.   Specifically, there might be difficulties in   communications between public health experts and microbiologists.   Possible public health implications of the findings of microbiologists might not be perceived without additional explanation.  I illustrated this with a specific article.

I used an excellent article to illustrate this problem.

The article is called “Contribution of Immune Activation to the Pathogenesis and transmission of HIV type 1 infection” and the authors are Stephen Lawn, Salvatore Butera and Thomas Folks.   (Clinical Microbiology Reviews. Oct 2001 14; 753-777)

This is part of what I said in California  in trying to illustrate the difficulty in communication:

“Of great interest – because of its implications for disease control was the discovery that other infections, viral, bacterial, protozoal and helminthic, could influence the course of HIV disease.  Generally the effect was to enhance HIV replication, but a few seemed to ameliorate – at least temporarily, the course of infection.  Scrub typhus, measles and perhaps a form of viral hepatitis, may have a  transient beneficial effect on HIV disease, but these are exceptional cases. Most co-infections have the opposite effect.

We now come to an example of observations made by microbiologists and work done at a molecular level with enormous implications for the control of AIDS in Africa.   This example is a review (cited above)  explaining in great technical detail how the replication of HIV can be enormously enhanced by concurrent endemic infections, and how this not only accelerates the progression of HIV disease, but also facilitates its transmission. The authors show in molecular detail how many viral, bacterial, protozoan and helminthic infections can affect HIV replication.  Included among these are common intestinal worms and water borne bacterial infections, causing severe diarrhea particularly in infants.  The discussion is largely concerned with the possible beneficial effect of drugs that might counteract this enhancement of HIV replication. There is one short sentence on public health interventions that might eliminate this problem altogether. It is of particular interest because of its brevity in a rather long article.   There is also a curious statement that where antiretroviral drugs are unavailable, measures to control endemic infections may be a useful approach.  This comment is reproduced below, and somehow ignores the significance of the implication that control of these endemic infections requires no other justification than as a measure to control AIDS.

This paper, because of its immunological and molecular detail is not too likely to find its way to an epidemiologist or public health expert,  but for one trained in these technicalities, I would suppose the public health implications would be immediately evident.

This particular paper also is a great illustration of the compartmentalization of information, and the difficulties of interdisciplinary communication.

Below is an illustration from the body of the article: there is much more just like this.  A person with no training in molecular biology or virology would not be likely to spend any time with this illustration.

lawn1

However if one turned a few pages the following diagram may just be of some interest. But again this is unlikely.

The part that would be of interest to a public health professional , if noted,  is contained in the large arrow at the bottom right of the illustration.  In this rather complex diagram it would be quite easy for the public health expert to be sufficiently distracted so that the bottom right hand corner would be easily missed.

lawn21

There is a long discussion, quite technical in nature, but at least the authors find space for the following brief comment.

“Prevention and Treatment of Coinfections

The widespread use of HAART in the treatment of HIV-

infected persons in westernized countries has resulted in a

phenomenal decrease in the incidence of opportunistic infec-

tions and has greatly increased survival. For these individuals,

the antiretroviral drugs are the major determinant of prognosis

and the potential cofactor effect of opportunistic infections is

now a more minor consideration. However, the vast majority

(>95%) of the world’s HIV-infected people do not currently

have access to antiretroviral drugs. Most of these people live in

developing countries, where the quality and access to health

care is often limited and where there is a high incidence of

endemic infectious diseases such as malaria, TB, and infections

by helminths and waterborne pathogens which may adversely

affect HIV-1 disease progression. Prevention or early treat-

ment of these diseases may therefore represent an important

strategy in addressing the HIV-1 epidemic in developing coun-

tries”. -

In the above quotation, the authors are overoptimistic in their assertion that the cofactor effect of opportunistic infections is now a more minor consideration in developed countries.  Valacyclovir, a drug that inhibits the replication of  many members of the herpes virus group, but has no direct effect on HIV was reported to reduce HIV viral loads in the absence of antiretroviral therapy. In the developed world, active herpes virus infections are common in the setting of HIV infection, although most will be asymptomatic. For example, Cytomegalovirus, Epstein Barr Virus and Human herpes virus type 6 are not infrequently found to be active in HIV infected individuals. Valacyclovir will have an effect on these viruses, and may well find a place in the treatment of HIV infection in developed countries.  Indeed it may not be uncommon for experienced physicians here (in the US) to prescribe related anti herpes medications to their HIV infected patients. I certainly do.

There is another aspect, a little more difficult to establish and perhaps altogether conjectural.  This is that we are presented with the question of why we need AIDS to justify interventions that have long been established to themselves improve the health of populations.  These include the provision of sanitation and clean water, the control of malaria and TB, and something as simple as getting rid of worms.  In the public’s assessment of the health needs of developing countries the information that is used is largely to be found in popular media, newspapers, magazines and TV.  Those who report in turn receive information from professional sources, and maybe it is here that the interdisciplinary barriers to communication I have been talking about have their effect. Thus the AIDS epidemic is perceived to be the greatest threat to the future of Africa, even though malaria kills more people, and common endemic infections contribute to an abysmal life expectancy.   (This was written 2-3 years ago and was probably incorrect even at that time;  estimates are that today there are  1.5-2 million deaths from AIDS in Africa, with close to 1 million deaths from malaria.  Malaria though  is responsible for a greater  number of deaths in children under 5 years of age).

It continues to be remarkable that although evidence has existed for years that many of these infections can interact with HIV infection to increase its infectivity and accelerate disease progression, those who advocate for, and allocate funds to fight HIV/AIDS seem oblivious to the relevance and implications of these interactions.

This effort of course needs absolutely no justification, but its funding is small compared to the resources that have been made available to combat HIV/AIDS –  but from all that has been described funding for these endemic infections is in fact also funding to fight HIV/AIDS “.

Those were comments made 2-3 years ago.

While malaria and tuberculosis are now receiving attention and are included with AIDS in some programs,   many other endemic infections  continue to be neglected.

Going back much further in time,  interest in the activating effects of associated infections on HIV replication began within the first 10 years of the epidemic.  This started with the demonstration that proinflammatory cytokines, TNF alpha or IL 6, for example could greatly accelerate HIV replication.

Of course these cytokines appear in the course of many different infections.  When viral load tests became available this effect was well understood by patients and physicians in N America and Europe. It became common wisdom that an HIV infected person who had a febrile illness, or had even received a flu vaccine  should delay viral load testing because the infection or vaccination was frequently associated with temporary rises in HIV viral loads.

The implications for geographic areas where the infections were far from temporary seemed to escape notice.

Thus endemic infections in Africa do have everything to do with HIV/AIDS.  There are numerous preventative and therapeutic measures available to control many of these infections,  and some are inexpensive.  Even something as simple as deworming may be useful.  Ascaris lumbricoides, the common intestinal round worm also is associated with immune activation and is easily got rid of.  There is a report that doing this with a drug called albendazole actually raised CD4 counts. (Walson JL et al. Albendazole treatment of HIV-1 and helminth co-infection: a randomized, double-blind, placebo-controlled trial. AIDS 22:1601-1609, 2008).

The person who has been studying immune activation and the association of parasitic infestations and AIDS for the longest time is  Zvi Bentwich.   I can’t remember when his first  publication on this issue appeared but by the mid 1990s he was publishing on this association in Ethiopian immigrants to Israel.   Zvi Bentwich deserves the greatest credit for his early recognition of the importance of this association, its significance regarding immune activation and for his continuing contributions.   He pointed out the relevance of schistosomiasis to AIDS  (and TB) at least 10 years ago.

The connection of so many endemic infections with AIDS  in Africa is also a connection of poverty with AIDS.  I saw an absurd and instantly forgettable paper entitled something like “Poverty does not cause AIDS” a few years ago.    Of course poverty is not the direct  cause of ascariasis,  schistosomiasis, tuberculosis, or any number of devastating infections.  Poverty is a very significant factor in  the acquisition of these infections, and as such can certainly be regarded as having a causative role.

The lives of impoverished populations are ravaged and shortened by these infections. Many of these infections also interact with HIV to compound the devastation they cause.  Poverty, multiple endemic infections and HIV are intimately intertwined and in many instances reciprocally affect each other.  For example the debility associated with schistosomiasis has an impact on an individual’s productivity, with economic consequences not only for the individual but for the larger community.

Controlling the AIDS epidemic in Africa must also include measures to prevent and treat the multiple endemic infections that affect hundreds of millions of individuals.

To conclude this post I want to recommend a book published about four years ago by Eileen Stillwaggon, a professor of economics.  It is called “AIDS and the ecology of poverty” and is published by the Oxford University Press.

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