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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

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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