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TreatmentUpdate 70
By Sean Hosein
Volume 8, no 6
September 1996
A publication of the Community AIDS Treatment Information
Exchange (CATIE).
Table of Contents
I ANTI-HIV AGENTS
A. How long should treatment be continued?
B. Ritonavir -- effect on survival
C. Indinavir -- with or without AZT and 3TC
D. Indinavir -- which dose is best?
E. Hydroxyurea -- one year later
F. Saquinavir and d4T
G. Saquinavir -- 2 or 4 times the normal dose
H. A cocktail of 5 anti-HIV drugs
II IMMUNOMODULATORS
A. Bone marrow stimulant may increase survival
B. DNCB and viral load
C. Enzyme therapy
D. High-dose IL-2
E. Malaria for AIDS
F. Transfer factor for HIV
III INFECTION FIGHTERS
A. High-dose AP for PCP?
B. Nitazoxanide for crypto
C. Garlic enemas for crypto?
D. Roxithromycin for crypto?
E. Three options for preventing MAC; which is best?
F. Using Biaxin(R) to prevent MAC; a risky decision?
G. A powerful combination for treating MAC in Canada
IV TESTING
A. Infections in American women
B. Deciding if a drug works
C. Practical uses for viral load
I ANTI-HIV AGENTS
We report below on selected abstracts and posters from the XI
International Conference on AIDS, which took place from July 7-12,
1996, in Vancouver. Most of the anti-HIV therapies reported here focus
on the newer protease inhibitors indinavir, ritonavir and saquinavir,
alone or in combination. All references are from the conference unless
otherwise noted.
A. How long should treatment be continued?
One research team studied the effect of combinations of
anti-HIV agents on subjects newly infected with HIV. They think that
these subjects will need at least 1.5 to 3 years of treatment to
eliminate all HIV-infected cells. In a recent issue of the journal
Science, a doctor reported that one of his patients who had been
taking anti-HIV combination therapy for 78 weeks decided to stop
therapy when technicians could no longer detect HIV in his blood or
lymph nodes (the doctor did not reveal the names of the drugs used,
but they probably included a protease inhibitor). "Within 1 week, high
levels of virus could be found in his blood."
REFERENCES:
1. Cohen J. Shooting for the moon with drugs. Science
1996;273(5273):302.
B. Ritonavir -- effect on survival
Researchers randomly assigned over 1,000 subjects to receive
ritonavir 600 mg twice daily or fake ritonavir (placebo). All subjects
had less than 101 CD4+ cells, the average ranging from 30 to 35 cells.
After 4 months, subjects receiving placebo could switch to ritonavir
if they developed new life-threatening complications or renewed
attacks of old infections, specifically:
PCP
ulcers due to herpes viruses
yeast infections in the mouth and throat
Subjects were allowed to continue taking whatever drugs they
were using before entering this study. Indeed, half the subjects were
taking 14 other drugs.
Who survived?
By the 6th month of the study, researchers found that roughly
4% of subjects on ritonavir
8% of subjects on placebo
had died. This difference was statistically significant; that is, not
likely due to chance alone.
Extracting meaning from numbers
It is difficult to assess the impact of ritonavir over the long
term because after 4 months, subjects who developed serious
complications were allowed to use ritonavir. Moreover, another study
found that ritonavir improved the ability of T cells to respond to
infections during the first month of therapy. After this time, T cell
function declined to its pre-ritonavir level. Nearly one year into the
study researchers reported the following events:
Event Ritonavir Placebo
Death 27 35
Yeast infections (oral) 18 41
Kaposi's sarcoma 8 20
PCP 10 22
CMV retinitis 18 17
Wasting syndrome 2 8
HIV and CD4+ cell counts
Some subjects who received ritonavir had an increase of at
least 50 CD4+ cells that was sustained for about one year. After
receiving ritonavir for 2 weeks, the amount of HIV in the blood fell
to 1/10th its pre-study level.
Toxicity
Subjects receiving ritonavir experienced diarrhea, tingling around the mouth (both inside and
outside) and nausea. Gradually increasing the dose of ritonavir over a period of 10 days, starting
with 600 mg/day, may increase patients' tolerance of the drug.
REFERENCES:
1. Cameron DW, Heath-Chiozzi M, Kravick S, et al.
Prolongation of life and prevention of complications in
advanced HIV immunodeficiency with ritonavir: update. Mo.B.411.
2. Pakker NG, Roos MTL, de Jong M, et al. Analyses of T cell
repopulation and restoration of T cell function during therapy
with different antiretrovirals. We.B.291.
C. Indinavir -- with or without AZT and 3TC
Background and Study details
In this study researchers compared the effects of different
regimens:
Indinavir alone
Indinavir with AZT and 3TC
AZT and 3TC
The drugs were taken in their standard doses: AZT 600 mg/day,
3TC 300 mg/day and indinavir 2.4 grams/day. Researchers assigned
subjects at random to each group. All 91 subjects were HIV-infected
adults (15 female, 76 male), at least half of whom had a CD4+ cell
count of 144 cells. No subject was supposed to have used a protease
inhibitor before entering this study. Neither doctors nor subjects
were supposed to know which combination of drugs was used.
Results -- HIV
Those subjects receiving the triple combination had a dramatic
reduction in the amount of HIV in their blood, averaging about 1/100
th their pre-study level, a reduction was sustained for 44 weeks.
Subjects receiving AZT and 3TC had the amount of HIV in their blood
fall by 50%. This reduction was sustained for the rest of the study.
Results -- CD4+ cell counts
Subjects who received AZT and 3TC had an average increase of 40
CD4+ cells compared with their pre-study levels. Those subjects
receiving indinavir alone or in combination had their CD4+ cell counts
rise by 100 cells. This increase was maintained for 9 months. Readers
should note that as the trial progressed, more subjects began to
leave.
Toxicity
Four subjects in the AZT/3TC group and 2 others
developed:
low levels of certain white blood cells called
neutrophils.
Twenty-two produced higher-than-normal levels of :
bilirubin.
Eight subjects receiving indinavir and one on AZT/3TC
developed
kidney stones.
REFERENCES:
1. Gulick RM, Mellors J, Havlir D, et al. Potent and
sustained antiretroviral activity of indinavir, zidovudine and
lamivudine. Th.B.931
D. Indinavir -- which dose is best?
In this study researchers tested three doses of indinavir:
2.4 g/day
3 g/day
3.2 g/day
Doctors reported results on 63 subjects who had been using
indinavir for about 1 year. By the 6th month of the study, the amount
of HIV in the blood of subjects had decreased to at least 1/100th of
its pre-study level. Half the subjects had an increase of between "80
to 145 CD4+ cells." By the 12th month of the study, production of HIV
remained as low as it had been 6 months earlier and subjects had 85
extra CD4+ cells than when they started. Technicians were not able to
detect HIV in "54%" of subjects. Readers should note this does not
mean that no virus was present, but simply that the equipment was not
sensitive enough to detect it. Doses of indinavir greater than 2.4
g/day do not appear to provide any benefit beyond that seen with 2.4
g/day.
Toxicity
About 50% of subjects had higher than normal levels of
bilirubin. This was detected in lab tests only, as subjects did not
have any signs/symptoms associated with this. Kidney stones did
develop in the following proportion of subjects:
2.4 g -- 10%
3.0 g -- 16%
3.2 g -- 12%
References:
1. Steigbel R, Berry P, Teppler H, et al. Extended
follow-up of patientsin a study of indinavir at 800 mg every 8
hours (2.4 g/day) and 800 mg every 6 hours (3.2 g/day).
Mo.B.412
E. Hydroxyurea -- one year later
Doctors in Italy recruited 60 HIV-infected subjects who had
more than 250 CD4+ cells. Twenty subjects received ddI 400 mg/day and
40 received the same dose of ddI as well as hydroxyurea 1 g/day.
Doctors monitored the subjects for up to 6 months.
Results -- combination
Once subjects started to receive both drugs the amount of virus
in their blood fell by over 90% compared to their pre-study level. Of
the 40 subjects on combination therapy, 18 remained in the study until
the 6th month. Production of virus remained low and CD4+ cell counts
remained stable.
Result -- ddi alone
Use of ddI also caused a dramatic decrease in production of HIV
during the first 2 weeks of the study, but after that it began to
rise. By the 6th month of the study the average amount of HIV in the
blood of these subjects had risen to 50% of its pre-study level. In
25% of subjects on ddI alone, levels of HIV in the blood returned to
pre-study levels by the 6th month of the study.
Results -- 7 subjects
The researchers also did experiments on 7 other subjects, 3 of whom
had AIDS. All subjects saw the amount of HIV in their blood fall to
1/10th its pre-study level. The researchers did not report any further
information.
REFERENCE:
1. Lori F, Foli A, Viale P, et al. Sustained absence of
viral rebound consistently observed in patients treated with
combination of hydroxyurea and didanosine. Th.B.942, programme
supplement.
F. Saquinavir and d4T
Doctors in Switzerland gave 14 subjects d4T 80 mg/day and
saquinavir 1800 mg/day. Before entering this study, half of the
subjects had used ddI for about 3 months. Twelve of the subjects had
survived at least one life-threatening infection. At the time they
entered the study half the subjects had a CD4+ cell count of 33 cells
and a CD8+ cell count of 449. None of these subject improved on other
older anti-HIV drugs.
Results
One month after entering the study half the subjects saw their
CD4+ cell count climb to 65 cells and by the second month, it had
reached 90 cells. Similarly, their CD8+ cell count increased to 599
cells during the first month, and in the second it rose to 696 cells.
Yet these increases were not statistically significant. During the
first month, blood levels of HIV fell to 1/100th their pre-study
level, but returned to 1/10th their pre-study level by the end of the
second month. This difference was statistically significant.
REFERENCE:
1. Rutschmann O, Kaiser L, Gabriel V, et al. Adding
saquinavir to d4T in advanced HIV-1 infection. Th.B.945.
G. Saquinavir -- 2 or 4 times the normal dose
Why increase the dose?
Although saquinavir can reduce production of HIV in laboratory
experiments, when taken orally more than 90% of the drug is not
absorbed or processed, which drastically reduces the amount of drug
that gets into the blood. As a result, researchers have been testing
between 2 and 4 times the licensed dose of saquinavir (1800 mg/day) to
see if absorption can be increased.
Study details
Researchers enrolled 40 HIV-infected subjects (1 female,
39 male) with CD4+ cell counts ranging between 188 to 527 cells, the
average being 346. Sixteen subjects in each group had less than 3
months of exposure to AZT and "related" drugs. Half the subjects
received "low-dose" saquinavir, that is, 3,200 mg/d. The other half
received "high-dose" saquinavir, that is, 7,200 mg/day. The drug was
supplied in 200 mg capsules, so some subjects "needed to take 36
[capsules] each day."
Results -- low dose saquinavir
CD4+ cell counts
Subjects in the low-dose group had an increase of 72 cells by
the 4th week of the study. By the 6th month of the study, this figure
had fallen to 31 cells. The increased cell count was statistically
significant until the 4th month.
HIV
The amount of HIV in the blood fell to 1/12th its pre-study
level by the 2nd week of the study. After that it began to increase
until by the 6th month, it had returned to near its pre-study level.
Results -- High dose saquinavir
The average
CD4+ cell count rose by 121 cells when subjects started using
saquinavir. Six months later the average increase was 82 cells. These
changes were statistically significant. Readers should note that all
subjects in this group had an increase of at least 50 CD4+ cells. The
difference in the increased CD4+ cell counts between the high-dose and
low-dose groups was statistically significant in the 3rd and 5th
months of the study.
HIV
In the high-dose group, production of HIV fell to 1/22nd its
pre-study level. After this, it began to increase slowly but still
remained below its pre-study level by the 6th month. This difference
between the level of HIV in the 6th month and the pre-saquinavir level
was statistically significant.
Toxicity -- low-dose group
Common signs/symptoms included:
fatigue
headache
muscle pain
diarrhea
low-blood sugar
Toxicity -- the high-dose group
Common signs/symptoms included:
headache
muscle pain
diarrhea
low levels of magnesium in the blood
According to the researchers, all subjects recovered from all of
these effects once they stopped taking the drug. They added, "Most
gastro-intestinal [problems happened during] the first 1 - 2 weeks [of
the study] and decreased or disappeared.... without [need to reduce
the dose]." Since subjects could tolerate the doses of drugs used in
this study, the researchers think that further experiments with these
doses of saquinavir and other antiviral drugs should be conducted. The
company that makes saquinavir is also testing a new form of the drug
in soft gel capsules. Researchers think that use of this product
should result in much higher levels of saquinavir in the blood. In
Canada that study in question is being coordinated at Sunnybrook
Hospital (Toronto).
REFERENCE:
1. Schapiro JM, Winters MA, Stewart F, et al. The effect
of high-dose saqunavir on viral load and CD4+ T cell counts in
HIV-infected patients. Annals of Internal Medicine
1996;124(12):1039-1050.
H. A cocktail of 5 anti-HIV drugs
Researchers used 6 subjects who had become infected within the
past 6 months. Subjects received standard doses of AZT, ddC, ddI and
interferon-alpha with or without 3TC. In some subjects, the use of
combination anti-HIV therapy caused a dramatic decrease in the amount
of HIV detected in their blood. Viral load (HIV RNA) fell to 1/1,000th
its pre-treatment level. One subject had a normal CD4+ cell count and
the amount of HIV RNA in his blood was less than 12 copies/ml.
REFERENCE:
1. Saget BM, Elbiek T, Guthries J, et al. Dramatic
suppression of HIV-1 plasma RNA using a combination of
zidovudine, didanosine, zalcitabine, epivir, and
interferon-alpha in subjects with recent HIV-1 infection.
We.B.533
II IMMUNOMODULATORS
A. Bone marrow stimulant may increase survival
Background
Less than normal levels of white blood cells can occur in some
people with HIV/AIDS, particularly those who have certain
infections_CMV and MAC_ or use certain drugs including:
AZT
Bactrim/Septrar
chemotherapy
ganciclovir
Reduced numbers of white blood cells make fighting infections
even more difficult. Doctors at a clinic in Copenhagen, Denmark who
have been conducting a study with the bone marrow stimulant G-CSF
(granulocyte-colony-stimulating factor, filgrastim, Neupogenr) report
interesting results. In their study, all subjects had less than 50
CD4+ (T4+) cells and low numbers of white blood cells - 1 billion or
less (normal range: 4 to 11 billion). Many subjects had low numbers of
a particular white blood cell call neutrophils - less than half a
billion (normal range: 1.8 to 7 billion).
Sixty subjects received G-CSF daily until their white blood
cell (WBCs) levels increased to 1.5 billion. Although the dose was not
stated, a common protocol is to use 300 æg injected under the
skin once daily for five consecutive days, followed by the same dose
on Monday, Wednesday and Friday until the WBCs increase to an
acceptable level. Once the 1.5 billion level was reached, the drug was
given three times weekly. In the meantime, doctors observed a similar
group of 104 subjects who had low levels of WBCs who were not given
G-CSF.
Results
At least half the subjects who received G-CSF lived for 658
days. The equivalent figure for subjects not receiving G-CSF was 511
days. This difference was statistically significant; that is, not
likely due to chance alone. These results may not be surprising in
light of some research done in the US. Doctors there gave "76
[subjects] at different stages of [HIV infection]" filgrastim 300
æg injected under the skin "four times daily every other day for
8 days." Doctors conducting the study found that the WBCs ability to
kill bacteria was increased to levels seen in non-HIV-infected people.
References:
1. Grutzmeier S, Gerstoft J, Boje HP, et al. Filgrastim
(G-CSF) use is associated with prolonged survival in
AIDS-patients with leukopenia and CD4+ cells < 50 x 106/L.
We.A.3094.
B. DNCB and viral load
In San Francisco, another research team reported their results
using the drug dinitrochlorobenzene (DNCB) on 8 subjects, 2 with AIDS,
one with mild symptoms of HIV infection and 5 with no symptoms. For a
detailed report on DNCB please read TreatmentUpdate 43. None of the
subjects had previously used DNCB, nor were they using anti-HIV drugs
while they were in this study. Researchers monitored subjects for 3 to
4 months.
Results
While using DNCB, all subjects had the amount of HIV in their
blood decrease to between 1/5th and 1/10th their pre-study level.
These decreases in viral load were statistically significant.
References:
1. Stricker RB, Goldberg B, Mills LB, et al. Decrease in
viral load associated with topical dinitrochlorobenzene (DNCB) therapy
of HIV disease. Th.B.4182.
C. Enzyme therapy
Background
A German product called Wobenzym(R), which consists of several
enzymes that can break up protein, fats and starch, is being tested in
New York. One idea drivingthe testing of this product involves
something called an immune complex. An immune complex is formed when
an antibody joins to whatever it is attacking, in this case HIV or its
proteins. Some researchers think that large numbers of these immune
complexes weaken the immune system's ability to fight infections. Some
believe that Wobenzym can "eat" these immune complexes, thereby
possibly improving the immune systems response to HIV-infection.
Doctors recruited 21 HIV-infected subjects who had between 200 and 500
CD4+ cells and gave them oral doses (precise dose was not revealed) of
Wobenzym. They reported results after subjects had been in the study
for 1 year. They also monitored 8 other HIV-infected subjects who were
not given the enzymes but who served as a group for comparing results.
Results
In general, the enzymes were well tolerated and appeared to
stabilize CD4+ cell counts and levels of HIV in the blood. Five
subjects had increased levels of a type of interferon called
acid-labile interferon alpha. In other studies, increased levels of
this form of interferon have been seen in subjects prior to them
developing AIDS. For details about this type of interferon please read
TreatmentUpdate 31. The researchers suggest further studies with the
enzyme preparation and anti-HIV drugs should be conducted.
Reference:
1. Lange M, Maitra U, Inada Y, et al. Effect of enzyme
therapy on HIV-RNA and CD4+ counts in HIV seropositive subjects
with CD4 count 200 to 500 cells. We.B.3198.
D. High-dose IL-2
In order to repair the
immune systems of people with HIV/AIDS, researchers are testing
chemicals that can increase the number of T cells. One of those
chemicals is interleukin-2 (IL-2). Researchers assigned HIV-infected
subjects to receive "one of 4 [schedules] of IL-2 twice a day for 5
days, either every 4 or 8 weeks." The doses and schedules were:
1.5 million units (MU) twice daily every 8 weeks
1.5 MU twice daily every 4 weeks
7.5 MU twice daily every 8 weeks
7.5 MU twice daily every 4 weeks
The average CD4+ count was 620 cells.
Among the subjects receiving 1.5 MU of IL-2, the average CD4+ cell
count rose above 800 cells during the first 6 months of the study.
Among subjects receiving the higher dose, the highest CD4+ cell counts
rose above 1,000 cells. The side effects seen with this drug included:
fever
headache
bone and muscle pain
fatigue
IL-2 therapy did not increase CD8+ cell counts. The researchers
noted that the amount of HIV in the blood did not increase
"significantly". Since subjects were relatively healthy, it was not
clear if the increased CD4+ cell counts will protect them from future
infections.
Reference:
1. Davy RT, Chaitt D, Kovacs J, et al. Subcutaneous
interleukin-2 therapy is capable of inducing marked sustained
increases in CD4+ counts in early HIV-infected patients. We.B.
290.
E. Malaria for AIDS
Earlier in this century, before the development of antibiotics,
some doctors treated their patients who had syphilis with malaria. The
theory was that the resulting fever would kill the germs that caused
syphilis. One research team in China observed that some of their
patients with AIDS and malaria lived longer than others who had AIDS
without malaria. Doctors there have given 8 HIV-infected subjects
malaria and looked for any changes. They claim that the patients' CD4+
cell counts have stabilized over a period of 6 to 18 months. They did
not release further details. It is not clear whether people with both
HIV and malaria in Africa have been studied to observe how the two
infections interact.
References:
1. Heimlich H, Chen XP, Xiao BQ, et al. CD4 response in
HIV+ patients treated with malariotherapy. We.B.3200.
2. Marussig M, R'nia L and Mazier D. Interaction between
AIDS viruses and malaria parasites: a role for macrophages?
Research in Virology 1996;147:139-145.
F. Transfer factor for HIV
Background
For the past 40 years researchers have known that it is
possible to "transfer" immunity against certain germs from a donor who
is immune to those microbes to other people who do not have this
immunity. The immune response that is transferred by means of what is
called "transfer factor" helps T cells contain infections caused by
certain "viruses, parasites, [bacteria] and fungi." The immune
response is called CMI (cell-mediated immunity) and it is critical in
fighting many of the infections seen in AIDS.
How transfer factor is made
To make transfer factor, healthy animals are injected with a
particular microbe. Several weeks later white blood cells from the
immunized animals are removed and processed to extract the transfer
factor(s). The factor can then be given by injection to a person with
weakened CMI. More recent experiments show that transfer factor can be
given by mouth and successfully "transfer" CMI.
Transfer factor for HIV
Researchers in Italy injected HIV into mice to stimulate their
white blood cells. Technicians extracted the transfer factor and gave
it to 24 HIV-infected subjects who took it orally along with AZT.
Twenty subjects had some symptoms of HIV infection but had not yet
developed AIDS. The remaining 4 subjects had AIDS.
Results
Symptoms/signs of HIV infection were reduced or cleared in the 20
subjects without AIDS. In 12 of the 20 CMI was restored. In at least 5
of the 20, CD8+ cell counts increased as did production of the T cell
growth factor IL-2. In two subjects, viral load was reduced to 1/10th
of their pre-study levels. Two subjects with AIDS remain alive 3 to 4
years after receiving the transfer factor.
Reference:
1. Chiodo F, Raise F, Gritti F, et al. HIV-specific
transfer factor. LB.B.6037.
III INFECTION FIGHTERS
A. High-dose AP for PCP?
Background
Doctors in Toronto enrolled 14 subjects with AIDS who had
developed the life-threatening lung infection PCP despite use of
aerosol pentamidine (AP) 300 mg/month. None of the subjects could
tolerate Bactrim/Septra(R) or dapsone. Doctors increased the dose of
AP to "300 mg every two weeks."
Results
Eight subjects died (cause of death was not released) and 6
subjects remained on the high-dose AP protocol and did not develop
PCP. The increased dose has not caused any increased toxicity.
Long-term observation continues.
Reference:
1. Lee-Pack L, Favell K, Lewis C, et al. High-dose
aerosol pentamidine for secondary prophylaxis of pneumocystis
carinii pneumonia in patients intolerant of other systemic
therapy. Tu.B. 2290.
B. Nitazoxanide for crypto
Study details Researchers in Mexico recruited 15 adults with
AIDS who had diarrhea caused by the parasite C. parvum (crypto). The
subjects had already tried other drugs including:
azithromycin
somatostatin (Octreotider)
spiramycin
but their diarrhea continued. Doctors gave some subjects NTZ
(nitazoxanide) 1 gram/day and others 2 g/day for between "10 to 30
days."
Results
Ten subjects recovered from crypto and technicians could not
find any parasites in their stool samples. The remaining 4 subjects
appeared to have diarrhea caused by CMV or bacteria. Doctors
interested in obtaining NTZ for their patients with crypto may call
Sandy Faulkner at Unimed Pharmaceuticals at 708-541-2525.
Reference:
1. Feregrino GM, Higuera
RF, Rossignol JF, et al. Extraordinary potency of the nitozoxanide. A
new antiparasitary against the Cryptosporidium parvum infections in
advanced AIDS. Th.b.4213.
C. Garlic enemas for crypto?
Doctors in Los Angeles have conducted a study using a chemical
found in garlic called allicin. The doctors told subjects with crypto
to mix 30 mg of allicin with 90 ml of water and drink. They were then
instructed to give themselves a "retention enema" with the second
dose. Fifteen of eighteen subjects in this study had less than 30 CD4+
cells.
Results
The doctors reported results from 18 subjects who had used the
drug for "at least 3 weeks." Eight subjects reported reduced diarrhea
and either gained weight or stopped losing weight. By the 6th week of
the study, 10 of 16 subjects had fewer bowel movements and their
weight stabilized or increased. In the 12th week of the study,
technicians could not find any crypto in stool samples from 4
subjects. Subjects complained about the taste and smell of the garlic
preparation, but no toxicity was reported. Further studies are
underway.
Reference:
1. Fareed G, Scolaro M, Jordan W, et al. The use of a
high-dose garlic preparation for the treatment of
cyrptosporidium parvum diarrhea. Th.B.4215.
D. Roxithromycin for crypto?
Background
Doctors in Brazil recruited 2 women and 21 men with AIDS who had
diarrhea for at least 1 month. These subjects were infected with the
parasite crypto. The average CD4+ cell count was 151 cells. Doctors
gave subjects roxithromycin 300 mg orally twice daily for 1 month.
Roxithromycin is 'related' to the antibiotics azithromycin,
clarithromycin and erythromycin.
Results
Eleven subjects recovered from diarrhea while 7 had less
frequent diarrhea or reduced numbers of C. parvum in their stool
samples. Five subjects did not respond to the drug. Roxithromycin
caused minor liver damage which healed once subjects reduced the dose
by 50% or stopped taking the drug.
Reference:
1. Sprinz E, Barcellos S, Bem DD, et al. A phase II
trial with roxithromycin in AIDS-related cryptosporidium
diarrhea. Th.B. 4211.
E. Three options for preventing MAC; which is best?
Background
In North America, when CD4+ cell counts fall to between 75 and
50 cells, people with HIV/AIDS are at increased risk for developing a
certain bacterial infection called MAC (mycobacterium avium complex).
Symptoms of MAC can include:
fever
night sweats
weight loss
painful intestines
diarrhea
loss of appetite
tiredness
A report on treatment for MAC appear later in this issue.
The antibiotic rifabutin taken at a dose of 300 mg/day can delay the
appearance of symptoms of MAC infection. We now report results from a
study comparing the effects of:
azithromycin 1200 mg once a week
rifabutin 300 mg/day
a combination of both regimens
Neither doctors nor subjects were supposed to know which drugs
subjects received. The CD4+ cell counts ranged between 47 and 57
cells. About 5% of subjects were female and 95% male. Researchers
randomly assigned the following subjects to receive:
azithromycin 233 subjects
rifabutin 236 subjects
combination 224 subjects
Results -- protection from MAC
After 1 year the researchers found that
the following proportion of subjects in each group developed MAC:
azithromycin 7.6%
rifabutin 15.0%
combination 3.0%
These differences were statistically significant. Clearly
subjects who received azithromycin were 50% less likely to develop MAC
than those who received rifabutin.
Results -- protection from other infections
Subjects receiving rifabutin were twice as likely to develop
certain bacterial infections in the lungs and sinuses than subjects
who received azithromycin.
Results -- survival
A total of 249 deaths were reported during this study, of which
an equal number occurred in each group.
Results -- toxicity
The proportion of subjects in the following groups reported
side effects:
combination 90%
azithromycin 86%
rifabutin 76%
Thus, subjects assigned to receive azithromycin alone or in
combination had more side effects than subjects who did not receive
that drug.
Side effects included:
painful intestines
diarrhea
nausea
vomiting
Deciding which regimen is suitable
Results from this study clearly suggest that azithromycin
alone or in combination with rifabutin is "more effective
than rifabutin [alone]".
The advantage of using azithromycin is that it need only be
taken once weekly, unlike rifabutin. Only about 11% of
subjects using azithromycin developed bacteria that were
resistant to that drug.
The combination of azithromycin and rifabutin is
clearly the most effective of the three regimens. Since
azithromycin need only be taken once weekly, side effects due
to azithromycin are limited to a few hours on one day.
Drug interactions
A disadvantage in using rifabutin is that it will interact with
the new anti-HIV drugs ritonavir and indinavir. Taking these drugs can
increase the concentration of rifabutin in the blood from 2 to 7 times
above normal. Indinavir and ritonavir do not have this effect on
azithromycin.
Reference:
1. Havlir DV, Dube MP, Sattler FR, et al. Prophylaxis
against disseminated mycobacterium avium complex with weekly
azithromycin, daily rifabutin or both. New England Journal of
Medicine 1996;335(6):392-398.
F. Using Biaxin(R) to prevent MAC, a risky decision?
Study details
Doctors in England, France, Germany and the US recently
reported their results using the antibiotic clarithromycin (also know
as Biaxin, Klaricid, Mavid and Zeclar) to prevent MAC infection in 667
subjects with AIDS. Researchers assigned subjects at random to receive
clarithromycin 500 mg taken every 12 hours or fake clarithromycin
(placebo). Roughly 90% of subjects were male and 10% female. At least
half of the 333 subjects who received the antibiotic had a CD4+ cell
count of 30 cells and a CD8+ cell count of 560 cells. Infections that
subjects had before entering this study included:
yeast infections in the mouth
PCP
hairy leukoplakia
shingles
Results -- who developed infections?
Six percent of subjects who received clarithromycin developed
MAC, as did 16% of subjects on placebo. This difference was
statistically significant.
Results -- survival
About 32% of subjects in the clarithromycin group died during
the study as did 41% of subjects who received placebo, a difference
that was statistically significant. The difference in survival
continued for about 2 years. By that time, however, only 28 subjects
remained on clarithromycin and 20 on placebo. Once subjects developed
MAC, the length of time they survived was the same whether or not they
received clarithromycin. Overall, subjects whose blood had MAC were
twice as likely to die as subjects who did not have MAC in their
blood.
Technicians were able to study samples of MAC-infected blood
from 19 subjects who received clarithromycin. They found that roughly
60% had MAC that could resist the effects of clarithromycin.
Results -- other infections
Subjects in the clarithromycin group had fewer bacterial chest
infections (2%) than subjects on placebo (6%). More subjects on
placebo (57%) needed to stay in a hospital than did subjects taking
clarithromycin (47%).
Toxicity
Subjects receiving clarithromycin were more likely to
experience certain side effects including:
nausea and/or vomiting
altered sense of taste
than subjects on placebo. Seventeen percent of subjects on placebo
left the study because of side effects as did 18% on clarithromycin.
What next?
Results from this study show that clarithromycin 500 mg every
12 hours can provide some protection against:
life-threatening MAC infection
bacterial chest infections
infection with a certain parasite (giardia)
Clarithromycin is one of two antibiotics that can suppress MAC
infection, the other being azithromycin. Most subjects on
clarithromycin who develop MAC were also likely to have MAC that could
withstand azithromycin. This event limits their options for effective
treatment. Some doctors may prefer to save clarithromycin for later
use as part of a treatment regimen. Others may use the 2 antibiotics
sparingly. Consider, for example, the previous study where
azithromycin was taken once a week with or without rifabutin.
References:
1. Pierce M, Crampton S, Henry D, et al. A randomized
trial of clarithromycin prophylaxis against disseminated
mycobacterium avium complex infections in patients with
advanced Acquired Immunodeficiency Syndrome. New England
Journal of Medicine 1996;335(6):384-391.
G. A powerful combination for treating MAC in Canada
Study details
Canadian doctors reported results from their study testing two
regimens in HIV-infected subjects who developed symptoms of MAC. All
subjects had detectable MAC in their blood, and were randomly assigned
to receive one of two regimens consisting of 3 or 4 drugs. The 3-drug
regimen consisted of:
clarithromycin 2 g/day
rifabutin 300 mg/day
ethambutol (see the following note)
A note on ethambutol
The dose of ethambutol was adjusted to the weight of each
subject. Those who weighed less than 60 kg received ethambutol 800
mg/day. To subjects who weighed between 60 and 80 kg, the researchers
gave 1200 mg/day. Subjects who weighed more than 80 kg received 1600
mg/day.
Rifabutin, adjusting the dose
When the study began researchers gave subjects in the 3-drug
group rifabutin 600 mg/day. At that dose many developed eye
inflammation so researchers reduced the dose to 300 mg/day. Five
percent of subjects in the 3-drug group were female and 95% male, as
were a similar proportion of subjects in the 4-drug group. Half of the
subjects had a CD4+ cell count of 10 cells. Over 90% of subjects had
less than 31 CD4+ cells.
Four antibiotics
Subjects in the 4-drug group received:
ciprofloxacin 750 mg twice daily
clofazimine 100 mg
ethambutol (dose adjusted as above)
rifampin 600 mg/day
Results -- symptoms
Subjects in the 3-drug group found that their symptoms of MAC
infection became less severe as early as the 2nd week of the
study. By the 12th week, at least 50% of the subjects in this
group had reduced symptoms of MAC infection compared to their
pre-study levels. This change was statistically significant.
Reducing the dose of rifabutin from 600 mg to 300 mg/day did
not affect changes in MAC symptoms.
Neither regimen was better or worse than the other in
reducing "fever or diarrhea".
Subjects receiving the 3-drug regimen lost less weight than
other subjects. This difference was also statistically
significant.
Subjects in the 3-drug group were able to carry out their
daily activities better than subjects in the 4-drug group, a
difference that was statistically significant .
Results -- survival
Half of the subjects in the 3-drug group survived for about 9
months while half the subjects in in the 4-drug group survived for 5
months. This difference in length of survival was statistically
significant.
Results -- levels of bacteria
It is important to remember that at the start of the study all
subjects had detectable MAC in their blood. Once subjects began to
receive treatment, technicians could not detect MAC in blood samples
from 29% of subjects in the 4-drug group and 69% in the 3-drug group.
This difference was statistically significant.
Toxicity
The risk of developing eye inflammation in the 3-drug group
was about 50% after 7 months. After researchers reduced the dose of
rifabutin to 300 mg/day the risk fell to 13%. Again, this difference
was statistically significant. One side effect noticed by the 3-drug
group was an altered sense of taste.
What's next?
What results from this study show is that a 3-drug combination
of clarithromycin, ethambutol and rifabutin is better treatment than a
combination of 4 older drugs. Compared to the 4-drug group, the 3-drug
combination group experienced:
increased survival
reduced symptoms of MAC
improved quality of life
How much clarithromycin?
It is clear from this and other studies that clarithromycin is
an important part of an anti-MAC treatment regimen. What is not clear
is how much clarithromycin is best. Other studies suggest that lower
doses of clarithromycin, ie., 500 mg every 12 hours, are less toxic
than higher doses. Due to their toxicity, higher doses may also reduce
survival. Readers should note that rifabutin and clarithromycin
interact. Rifabutin reduces levels of clarithromycin in the blood by
about 50% and clarithromycin increases levels of rifabutin by 77%.
This is why the Canadian researchers used such a high dose of
clarithromycin. According to their calculations, the mix of
clarithromycin and rifabutin used in this study should result in
levels of clarithromycin that would be similar to those found in
subjects taking clarithromycin 1 g/day. Results from studies using
azithromycin in combination with other antibiotics as anti-MAC therapy
are needed. This Canadian regimen may not be the best anti-MAC
therapy, but it is much better than combinations of older drugs.
References:
1. Shafran SD, Singer J, Zarowny DP, et al. A comparison
of two regimens for the treatment of MAC-bacteremia in AIDS:
rifabutin, ethambutol and clarithromycin versus rifampin,
ethambutol, clofazimine and ciprofloxacin. New England Journal
of Medicine 1996;335(6):337-383.
IV TESTING
A. Infections in American women
Doctors in New Jersey have been reviewing their records to
determine which infections were responsible for the deaths of their
female patients in 1994. Of the 36 cases studied, most died within 4
years of being diagnosed with HIV infection. "At the time of death,
56% of the [patients] had less than 50 CD4+ cells." At the time of
their deaths, the following complications/diseases were present in
these women in the proportions indicated:
42% wasting
39% TB or MAC
31% bacterial pneumonia
28% PCP (in the past).
Other, less common complications were reported:
2 subjects had PML (progressive multifocal
leucoencephalopathy -- a brain infection)
one had severe brain damage due to HIV
three had toxo. During the years the patients visited the
clinic, only 19% did not have cervical cancer, while 78% had
vaginal yeast infections.
Reference:
1. Klose PC, Corell P, Eyassu R, et al. Rates of
opportunistic infections and disease conditons in clients of
the Newark women's AIDS clinic (NWAC). We.C.3403.
B. Deciding if a drug works
Survival
According to one British researcher:
"There are many different anti-HIV drugs being developed and
there is a great wish to assess new treatments and complex drug
combinations as quickly as possible. However, the slow natural
history of HIV-infection means that controlled trials using
[death] as an end-point inevitably take several years to
complete. Even trials on [subjects with symptoms who die] more
rapidly, require many thousands of patient-years of
observation. It is therefore highly desirable that techniques
should be developed which can assess more quickly the
effectiveness of drugs. In order to achieve this, [laboratory
tests], have ben adopted in the hope that they are reliable and
effective."
CD4+
One lab test or marker that has been used is the CD4+ cell
count. However, changes in CD4+ counts do not always result in
decreased symptoms or decreased risk of death. Therefore,
pharmaceutical companies have now begun looking for other surrogate
markers. Currently their focus is on viral load, particularly the
amount of viral RNA in the blood.
Why viral load?
One reason for choosing to measure viral load is that changes in
this marker are supposed to be linked to damage to the immune system.
That is, as viral load increases, CD4+ cell counts should fall and
patients should normally be at increased risk of life-threatening
infections or death. "Repeated measurements can be easily performed on
each patient and changes in viral load accurately followed over weeks
and months. Therefore only a small number of patients needs to be
studied to obtain a repeatable result." While there are a number of
problems with this rationale, and "there are no published data from
controlled clinical trials [of an anti-HIV agent] as yet," an American
group of researchers has recommended that regular monitoring of the
amount of HIV RNA (viral load) be used to help doctors manage their
HIV-infected patients. Information from several studies support that:
"There is a reasonable belief that the more viral load is suppressed
and the [longer it is kept suppressed], people with HIV/AIDS will get
better." As more doctors begin to monitor viral load, the benefits of
this test will become clear.
REFERENCES:
1. Peto T. Surrogate markers in HIV disease. Journal of
Antimicrobial Chemotherapy 1996;37(supplement B):161-170.
2. Mellors JW, Rinaldo CR, Gupta P, et al. Prognosis in
HIV-1 infection predicted by the quantity of virus in the
plasma. Science 1996;272:1167-1170.
3. Saag MS, Holodniy, Kuritzkes DR, et al. HIV viral
load markers in clinical practise. Nature Medicine 1996;
2(6):625-629.
4. Serum HIV-1 RNA levels and the time to development of
AIDS in the multicentre Hemophilia cohort story. Journal of the
American Medical Association 1996;276(2):105-110.
5. Phillips AN, Eron JJ, Bartlett JA, et al. HIV-1 RNA
levels and the development of clinical disease. AIDS
1996;10(8):859-865.
C. Practical uses for viral load
The American arm of the International AIDS Society recently
convened a panel of researchers to make recommendations about the use
of viral load, that is the measurement of HIV-1 RNA in the blood.
Results of viral load measurements are reported as copies/ml, for
example, 5,000 copies/ml.
Regular use of viral load
at the beginning of therapy: 2 viral load tests, 2 - 4 weeks
apart
every 3 to 4 months or when CD4+ cell counts are performed
more frequently when considering a change in anti-HIV therapy
3 - 4 weeks after starting/changing therapy
When to start anti-HIV therapy?
"The goals of anti-[HIV therapy] are to limit or delay
[worsening symptoms, falling CD4+ cell counts] and, to increase
survival." Doctors should begin treatment when: l there are between
5,000 and 10,000 copies per ml and CD4+ cell counts are low or falling
and/or symptoms of HIV appear or become worse; l there are between
30,000 and 50,000 copies/ml regardless of [CD4+ cell counts], even if
there are no or few symptoms of HIV infection.
How low should viral load be suppressed?
The panel recommended that blood levels of HIV RNA be reduced
as low as possible -- "undetectable". If this is not possible then a
goal of less than 5,000 copies per ml is "acceptable." When is it time
to change anti-HIV therapy? When viral RNA levels in the blood rise
"toward (or within 0.3 to 0.5 logs of) pre-treatment values."
How can one tell that anti-HIV therapy is working?
For a treatment to be considered useful, levels of HIV RNA in
the blood should decrease by at least 0.5 log. Which test should be
used? Currently there are three test kits in use:
branched chain DNA
NASBA
RT-PCR
The panel recommends that the same test "should always [be used] in
the same individual patient."
References:
1. Saag MS, Holodniy, Kuritzkes DR, et al. HIV viral
load markers in clinical practise. Nature Medicine 1996;
2(6):625-629.
2. Kuritzkes DR. Plasma HIV RNA quantitation. Improving
the Management of HIV disease. 1996;4(2):11-15.
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