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Effectiveness
and
Safety
of
Abacavir,
Lamivudine,
and
Zidovudine
in
Treatment-naïve
HIV
Patients
Initial
controlled
trials
with
the
combination
of
abacavir
(Ziagen),
lamivudine
(Epivir)
and
zidovudine
(Retrovir)
[ABC/3TC/ZDV;
Trizivir]
showed
equivalent
efficacy
to
the
regimen
of
indinavir
(Crixivan),
lamivudine,
and
ZDV
in
achieving
a plasma
HIV-1
viral
load
(pVL)
<400
copies/mL
at
48
weeks
in
treatment-naive
(ART-naive)
HIV
patients. The
virologic
response
of
this
triple-nucleoside
reverse
transcriptase
inhibitor
(NRTI)
regimen
was
later
shown
to
be
inferior
to
that
of
efavirenz
(Sustiva)-based
regimens
and
also
to
that
of
indinavir-based
regimens
in
patients
with
a high
pVL. For
this
reason,
current
guidelines
for
the
initial
treatment
of
HIV-1-infected
patients
recommend
2 NRTIs
combined
with
a non
nucleoside
reverse
transcriptase
inhibitor
(NNRTI)-or
boosted
protease
inhibitor/ritonavir-based
(PI/r)
regimen
and
consider
the
triple-NRTI
regimen
of
ABC/3TC/ZDV
as
an
alternative
only
when
a preferred
regimen
cannot
be
used. The
aim
of
the
current
retrospective
study,
published
in
the
current
issue
(February
1,
2006)
of
the
Journal
of
the
Journal
of
Acquired
Immune
Deficiency
Syndromes
was
to
analyze
the
safety
and
effectiveness
of
abacavir,
lamivudine,
and
zidovudine
(ABC/3TC/ZDV)
in
antiretroviral
therapy
(ART)-naive
HIV-infected
patients
enrolled
in
an
observational
cohort
study The
investigators
analyzed
all
consecutive
ART-naive
HIV-infected
patients
who
initiated
ABC/3TC/ZDV
in
71
centers
throughout
Spain
and
had
a clinical
visit
and
laboratory
data
at
least
16
weeks
after
initiating
this
regimen.
They
assessed
safety,
mortality,
new
AIDS-defining
conditions
(ADCs)
and
treatment
failure,
the
latter
defined
by
any
of
the
following:
(1)
reduction
in
plasma
HIV-1
viral
load
(pVL)
<1
log
during
the
first
12
weeks
of
ART,
unless
it
was
less
than
the
lower
limit
of
quantification
(LOQ);
(2)
failure
to
achieve
a pVL
<LOQ
after
24
weeks
of
ART;
and
(3)
rebound
to
2 consecutive
pVLs
≥LOQ
after
achieving
a pVL
<LOQ. Results -
A
total
of
730
patients
were
included,
median
patient
age
was
37
years,
prior
ADCs
occurred
in
20%,
median
pVL
was
4.76
log,
and
median
CD4
count
was
255
cells/mm3;
109
(14.9%)
patients
had
<100
CD4
cells/mm3.
-
After
a median
follow-up
of
50.5
weeks,
104
(14.25%)
patients
discontinued
therapy
because
of
adverse
events
and
36
(4.93%)
had
a suspected
hypersensitivity
reaction
to
abacavir
(ABC).
-
The
frequency
of
treatment
failure
according
to
an
intention-to-treat
(ITT)
analysis
of
observed
data
was
14.4%.
-
In
a more
rigorous
approach
considering
losses
to
follow-up
and
interruptions
or
switches
of
therapy
as
failures,
however,
the
frequency
of
treatment
failure
was
22.92%.
-
Factors
independently
associated
with
treatment
failure
by
observed
data
ITT
analysis
were
adherence
<90%,
methadone
use,
baseline
pVL,
and
prior
ADC.
In
conclusion,
the
study
authors
write,
“The
triple-nucleoside
regimen
of
ABC/3TC/ZDV
is
a reasonable
option
for
ART-naive
patients
with
a pVL
<100,000
copies/mL
in
whom,
for
any
reason,
preferred
regimens
are
not
advisable,
even
in
patients
with
a baseline
CD4
cell
count
<100
cells/mm3.” 01/13/06 Reference
J
Berenguer
and
others.
Effectiveness
and
Safety
of
Abacavir,
Lamivudine,
and
Zidovudine
in
Antiretroviral
Therapy-Naive
HIV-Infected
Patients:
Results
From
a Large
Multicenter
Observational
Cohort.
Journal
of
Acquired
Immune
Deficiency
Syndromes
41(2):
154-159
.
February
1,
2006. 
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