CPT-11 - Clinical Cancer Research

Vol.
4, 2747-2754,
November
Irinotecan
Alex
Eric
J. Loos,
Brouwer,
Jaap
Kees
J. van
Robbert
H. J. Mathijssen,
Ron
Metabolism
and
Gerrit
Aiphen,
findings
Rotterdam
Hospital
Cancer
Rotterdam,
Institute
for
excretion
only
this
13.3%
data
should
evaluation
of this
(CPT-11).
Ten
patients
with
histologi-
is one
of the
clinical
trials
against
several
cancers
and
infusion
bipiperidine)-l
feces
were
collected
reversed-phase
assay
for
56
h and
drug
liquid
and
to date: SN-38;
(SN-38G);
Plasma,
urine,
analyzed
high-performance
for the parent
identified
-glucoronide
or 80 mg/rn2).
all four
by
and
a specific
chromatographic
metabolites
positively
its -glucuronide
conjugate,
7-ethyl-1O-[4-N-(5-aminopentanoic
acid)-1-piperidino]-carbonyloxycamptothecine
(APC);
all
compounds,
drug
[25.6
with
± 5.71
the main excretion
was only a minor
a clear
predominance
Total
with
2.45%
by bacterial
tabolites
urinary
minor
15.8
unexpectedly
of intestinal
3-glucuronidase.
overall
contribution
parent
± 3.51
M
was
28.1
from
and
SN-38G
clearance
fecal
oxycamptothecine
and
former
lesterase
side chain
converting
feral
and
the other
extracts,
with
of the cytochrome
liver
an
small
further
idine
group
major
The costs
of publication
of this article
were
defrayed
in part by the
of the American
I, 1998,
2
in New
To whom
Association
Orleans,
requests
for Cancer
Research,
held March
SN-38.
Fig.
1 is
The
and
I
to
converting
in serum
preliminary
(4),
evidence
activity
within
the
drug
activity
(7,
in
1). Be-
thought
Peripheral
characterized
(6),
tumor
may
8).
SN-38
mediated
by UDP glucuronosyl3-glucuronide
derivative,
SN-
on
been
the
C-b
there
is an
CPT-
1 1 and
drug
in humans.
than
APC
metabolites
to determine
Thus,
metabolism,
need
the
this
establish
complete
here,
we
and
urinary
of the
have
been
have
and
shown
culture,
fecal
to
the
effects
of NPC
examined
(14)
not yet
in
no reports
a mass
metabolic
have
as APC
in vitro
a
to the
pathway
to biological
have
elimination
to
rise
was recently
in
there
of
piper-
structures
metabolitcs
SN-38
and fecal
urgent
gives
and coworkers
Although
other
from
minor
In addition,
urinary
Thus,
disposition,
and
unknown.
which
1 resulting
active
consists
of the terminal
( 12, 13). The
1). Other,
identified.
of this
chain,
by Rivory
see Fig.
biologically
is still
side
of CPT-l
positively
less
1 1 metabolism
oxidation
compounds
established
(15;
CPT-
of
3A-mediated
metabolites
and NPC
payment
of page charges.
This article
must therefore
be hereby
marked
advertisement
in accordance
with
18 U.S.C.
Section
1734 solely
to
indicate this fact.
I This
work was previously
presented
in part at the 89th Annual
Meeting
of
factor
of several
recently
8/18/98.
po-
1).
a topoisomerase
CPT-l
has been
intestine
pathway
the quantitative
6/3/98; revised 8/13/98; accepted
(Fig.
see
as
systems,
vitro
metabolism,
to an inactive
,
P-450
contribution
Received
1.4’C-b
(9-11).
formation
vivo
unique
bulky
at the
position
potent
carboxylesterase
1A I
a
(3;
a prodrug
important
cytochrome
be
in
as
and
Another
been
C-7
more
in animals
that
be
38G3
Surprisingly,
>100-fold
vivo
(5),
transferase
7-ethyl-1O-[4-N-(5-aminopentanoic
of
located
cancer
I is
can be cleaved
enzyrnatically
by a carboxyenzyme
that generates
the active metabolite
activity
undergoes
a very
CPT-l
because
the
gyneco-
colorectal
chain
at
entered
of clinical
including
Structurally,
side
group
in various
±
me-
2).
drugs
ethyl
is
in
range
disorders,
(7-ethyl-1-hydroxycamptothecine)
as
P-450-mediated
acid)-1-piperidino]-rarbonyloxycamptothocine.
an
SN-38
also
7-ethyl-1O-[4-N-(1-piperidino)-1-amino]-carbonyl.
compounds
with
indicates
average,
of SN-
1 and
1, 7-ethyl-
to have
a broad
5-fluorouracil-refractory
Refs.
sition,
h
of SN-38
concentra-
high (on
hydrolysis
CPT-11
for
of the
excretion
CPT-l1
products.
Whereas
renal
route of drug elimination,
also be identified
could
versus
unchanged
of this compound
were
of the dose), suggestive
dons
in plasma
neoplastic
[CPT-l
agents
displaying
‘-carboxylate
function
enzyme
was observed
. h (CPT-11)
p.M
(total metabolites)].
10.6% of the dose,
38G
decline
antiturnor
years,
camptothecine
inhibitor
and
(NPC).
A three-exponential
among
cause
7-ethyl-1O-[4-N-(l-piperidino)-1-amino]-carbonyloxycamptothecine
in
SN-38
SN-38
promising
logical
(reviewed
(60
most
in recent
activity
cal proof
of malignant
solid
tumor
received
200 mg/m2
CPT-11
as a 90-mm
i.v. infusion,
followed
by a 1.5-h i.v.
of cisplatin
to
drug.
INTRODUCTION
The objective
of this study was to determine
the metafate and disposition
of the antitumor
camptothecine
irinotecan
The
as a guide
(Daniel
3008 AE
ABSTRACT
derivative
that
further
metabolites.
The topoisornerase
I poison
irinotecan
lO-[4-(l-piperidino)-l-piperidino]-carbonyloxycamptothecine]
bolic
some
of importance
be
2747
of the dose,
indicate
constitute
or nonfluorescent
study
therapeutic
±
These
may
Research
Patients1
24.4
of -52%.
in urine and feces
from
further
of Medical
Oncology,
Kliniek)
and University
the Netherlands
accounted
nonextractable
unknown
and
Cancer
in Cancer
to a total
of the dose
half
Verweij
Department
den Hoed
Rotterdam,
excretion
leading
Nooter,
Stoter,
Disposition
feral
J. A. de Jonge,
Maja
de Bruijn,
Walter
Clinical
(CPT-11)
Sparreboom,2
Peter
1998
and
balance
on
APC.
for
fate
of this
the
plasma
excretion
path-
29-April
LA.
for reprints
should
be addressed,
at Department
Medical
Oncology,
Rotterdam
Cancer
Institute
(Daniel
den Hoed Kliniek)
and University
Hospital
Rotterdam,
P.O. Box 5201, 3008 AE Rotterdam,
the Netherlands.
Phone:
31.10.4391112;
Fax:
31.10.4391113;
E-mail:
[email protected].
of
The abbreviations
used
are: SN-38G,
SN-38
-glucuronide;
APC,
7-ethyllO-l4-N-(5-aminopentanoic
acid)- I -piperidinol-carbonyloxycamptothecine;NPC.7-ethyl-lO-[4-N-(
I -piperidino)I -amino]-carbonyloxycamptothecine;
HPLC.
high-performance
liquid
chromatography;
3
AUC.
area under
the plasma
concentration-time
curve.
2748
Irinotecan
Metabolism
in Humans
CH,CH,
CH)CH
iv.
N-CN(o2\
oa(
0
APC
H,CH,C
OH
H,CH,C
OH
0
3A
45O
or tropisetron
(3 mg
of the CPT-l
to start
24 h. The
Cancer
Institute
consent
forms
H,CH2C
OH
carboxylesterase
CH,CH,
Premedication
was
for
were
CPT-l
from
lithium
I13CH2C
x
3000
polypropylene
1 and
a vein
in the
were
vials
informed
sufficient
its
5, 8.5,
which
was
Hamburg,
used
for
tubes
con-
for 5 mm at
stored
frozen
Germany)
SN.38
frozen
of feces
in microtubes.
Complete
in polystyrene
volumes
bursts
collections
containers
of 5%
feces
OH
0
aqueous
perchloric
T25
homogenizer
Fig. 1 Chemical
structures
of irinotecan
(CPT- 1 1) and four human
metabolites:
SN-38,
SN-38G,
APC, and NPC.
UGT IAI,
human
UDP
glucuronosyltransferase
isoform
1AI;
CYP45O
3A, cytochrome
P450
isoform 3A.
ways
of CPT-l
1 in a group
a recently
developed
detects
all currently
of patients
analytical
identified
with
method
metabolites
solid
based
(16,
tumors
chloride
(batch
(batch
LIE783)
and were
measured
that
used
by
whereas
tion
Patients
and Treatment.
of CPT-l
1 were
a Phase
I study
histologically
quate
study.
studied
was
chemotherapy
prior treatment
hepatic,
had no
and platinum
derivatives.
a
d-sorbitol
pH
3.5-4.5
(as
and
and
patients
participating
with
(18).
All patients
of a malignant
forms
and
Vials
hydrochloride
a lactic
were
acid-sodium
provided
that
by
in
form)
hydroxide
Rh#{244}ne-Poulenc
a
adeof
buffer
Rorer
Cedex,
France).
The CPT-l
1 dose of 200 mg/rn2
was
tered as a 90-mm
iv. infusion,
followed
immediately
system
in
Ref.
using
rpm.
five
1-mm
Aliquots
human
of the
plasma
and SN-38
19),
and
prior
feces,
(17).
The
analysis
of plasma,
were
(w/v)
of total,
the drug
rocked
and
on
i.e.
sulfate
acid.
The
,
at 24,000
the extracts
acetate
(3:7,
diluted
v/v),
latter
was
carboxylate,
for
adjusted
extracts
were
and J. Verweij,
5
10 msi
to pH
5.3
transferred
unpublished
allow
or
of
the
esti-
mm,
were
followed
clear
with
by
super-
methanol-
tetrabutylammowith
hydrochloric
to limited
data.
of
samples
(4#{176}C).
The
(Antony
A. Sparrcboom
urine,
concentrations
2-10-fold
containing
to
The
5 mm
diluted
proved
of a mixture
i.l
acid
mixer
X g for
was
method
plasma-diluted
500
simultaneously.
vortex
SN-38G
of NPC.4
with
plus
1 and
were
(16),
the methodology
perchloric
lactone
a multitube
arnmonium
nium
aqueous
its rnetabolites
from
M
acidified
Rorer
in plasma
method
of CPT-l
and
for concurrent
aliquots
hydrochloride
SN-38
HPLC
quantitation
in urine
250-i.l
homogenate
SN-38
CPT- 1 1 and
described
as described
rnethanol-5%
4
to
(batch
(batch
hydro-
by Rh#{244}ne-Poulenc
of
adminisby a 3-h
(17).
in five
(IKA-Labortechnik,
supplied
Briefly,
natant
40 or 100 mg of
formulated
acid
with
suitable
feces
0. 1
kindly
as received.
a previously
centrifugation
excluding
I inhibitors
143;
were
modified
mation
tumor
had
functions
at the time
one prior combination
contained
trihydrate
also
in
had
solid
of therapy
and renal
more
than
disposi-
cisplatin
regimen
or two single-agent
regimens,
with CPT- 1 1 or other topoisornerase
CPT-l
1
diagnosis
to standard
hematopoietic,
All patients
metabolism
1 in combination
malignancies
confirmed
refractory
The
EBO1
for simultaneous
further
in 10 adult
of CPT-l
nonhematological
various
that
METHODS
AND
at
of SN-38G
individually
at 20,500
diluted
also
sample
processing
as described
above
for urine.
Determination
of CPT-11
and Metabolites.
Pure refer-
and of APC
MATERIALS
operating
were
were
immediately
ence
standards
of CPT-l
1 hydrochloride
trihydrate
K0l6)
and the metabolites
SN-38G
trifluoroacetate
YE0265),
NPC trifluoroacetate
(batch
YE0304),
APC
using
on HPLC
17).
Germany)
stored
degradation
homogenized
(w/v)
homogenates
further
and
of an Ultra-Turrax
Dottingen,
HCHC
(i.e.,
and 0.5-ml
aliquots
plasma
and stored
-80#{176}C to prevent
continued
Weighted
feces samples
were
SN-38
were
up to 56 h after start of drug administration),
were diluted
I : 1 (v/v) with drug-free
human
obtained
G
in
at -80#{176}C
until the time of analysis.
Complete
urine
collections
obtained
for the duration
of the study during hospitalization
HO)#{231})rNo
11,
samples
to that
in glass
immediately
plasma,
1, and
All blood
opposite
ob-
0.5,
1, 1.5, 2,4,
and centrifuged
Blood
were
infusion;
collected
to
analysis.
metabolites
before
arm
(Eppendorf,
plasma,
1 1 administration
in the HPLC
points:
Samples
heparin
iv.)
repeated
signed
the end of infusion.
g (4#{176}C)to yield
rng
it was
by the Rotterdarn
CPT-
and0.17,0.33,0.5,
56 h after
(10
and
patient,
before
time
infusion;
(8 rng
the study.
peaks
of
1 infusion.
dexamethason
In each
analysis
drawn
CPT-l
,
(b)
was approved
interfering
and
48,
of (a) ondansetron
and all patients
obtained
at the following
taming
SN-38
mg/rn2).
1 infusion,
entering
was
possible
32,
and
Board,
before
1.5 hduring
24,
\N
80
protocol
Review
feces
samples
0
iv.)
Collection.
and
tamed
N
clinical
Sample
evaluate
-.-
or
consisted
prior
urine,
LJ)
(60
and
iv.)
CH,CH
CNCNOINO
CPT-11
cisplatin
just
after
CVP45O
of
for all patients
uniform
OH
NPC
infusion
0
volume
Clinical
inserts,
system.
and l00-200-.i.l
The system
was
solvent
delivery
system,
vice,
and a fluoriMonitor
Analytical,
were
inner
Riviera
achieved
diameter,
squares
an autoMetric
4100
4100
fluorescence
eters
minimizing
FL).
im
5
column
a SpH99
oven
size;
Injected
anol-0.1
M ammonium
acetate
containing
monium
sulfate
(v/v)
for CPT-l
plasma
urine,
[35:65
only or 30:70
(v/v)
and feces homogenate].
at 1 .0 mLlmin,
tation
and
lively.
analysis
computer
Italy).
running
The
over
ng/ml
100-5000
ng/ml
curves
were
logical
matrix
function
and
ious
samples
squares
in plasma,
homogenate.
using
Development
Co.,
bio-
regression
Lotus
New
for
Version
York,
CPT-
the between-run
and
levels
Siphar
termination
NY).
within-run
for
Version
multiexponential
tamed
by
4.0
and
each
variabilities
compound
functions.
numerical
minimize
any
(SIMED,
were
The
the
of the plotted
Initial
parameter
(Hyclone,
Life
algorithm
based
function
separately
and
o
fit
was
tical
best
of
calculated
by
an
ing
(20),
as
described
trols
was
and
determined
Amsterdam,
logarithmic
units/ml
added
plated
the
growth
air in
bovine
penicillin,
L-glutamine
100
(all
MD).
Exponentially
(2000
cells/well)
Cambridge,
the metabolites
in
MA), 48 h before
were
dissolved
concentrations
incubation
aqueous
assessed
with
tested
of
-2
period
Cell
minor
p.g/ml
in at least
was
plotted
in the absence
APC).
in the
5 days.
modifications
survival
in medium
of
trichloroacetic
acid,
using sulforhodamine
in quadruplicate
experiments.
incubated
a 90-mm
with
were
on the Powell
ob-
After
inhibition
B stain(21).
Each
three
mdc-
relative
to con-
of drug.
i.v.
malignancy,
clinical
solid
bilirubin
method
to
level
and
disease
of 87
SD
determined
for
respectively,
the
by
ith
and
are
for the
observation.
application
Y,
ith ob-
The
of (a)
the
statis-
Akaike’s
be
(18).
reported
cancer
7-1 1 i.M);
15 jiM);
protein
Only
treated
two
according
the
median
a total
creatinine
aminotransferase
of
19 units/liter
(range,
13-27
concentrations
(range,
units/liter),
of
of the participants
73
g/liter
in the study
to conventional
a 5-fluorouracil-containing
in
being
a serum
aspartate
units/liter
as
Full
six men and four
Each patient
had a
colorectal
levels
18
total
glliter).
will
in 10
1 given
protocols,
chemotherapeutic
reg-
imen.
Analytical
the composition
Method.
To gain a preliminary
insight
of the CPT-l
1 metabolites
in plasma,
urine,
feces, samples
from patients
procedure
(16). This assay
fled,
rnatographic
and
and
previously
as the ratio
the variance-covariance
and
69-78
with
72-1
aminotransferase
units/liter)
CPT-1
cisplatin
responses
(range,
i.M
(range,
.LM
alanine
matrix
using
between
of 8
with
with
performed
of
present
in 7 of 10 cases. The
for
all 10 patients
included
values
level
trial
group
consisted
of
from 36 to 66 years.
type,
chemistry
an
were
Y0,
treatment
refractory
(range,
observations;
and
The
in age
predominant
were
a Phase
infusion
toxicities
studies
I clinical
in combination
into
detail
elsewhere.
women,
ranging
with
criteria:
pharmacokinetic
entered
of the
computed
fitted
colon
carcinoma
cell line
cell line IGROV1 were
Gaithersburg,
(Costar,
1 1 and
(w/v)
was
information
criterion
with the x2 test to discriminate
models
and (b) the coefficient
of correlation,
defined
SD
were
(Brunschwig,
to obtain
followed
always
-
Y values,
is the
plates
CPT-
Complete
I
number
and
(Tmax)
UT), 100
2 msi freshly
Inc.,
fixation
with 10%
of cell proliferation
typically
servation;
best
(Cmax) and the
in continuous
trypsinized
in DMSO
medium,
patients
by de-
procedure,
by the following
[(Y0
i=
observed
of the
(SN-38)
and -20
i.g/rnl
(CPT-l
1, SN-38G,
NPC,
and
The compounds
were added to the cells by serial dilution
respectively;
F =
n is the
Logan,
and
were
96-well
culture
drug exposure.
15-42
where
kept
Technologies,
cells
at var-
curves
estimates
peeling-algorithm
objective
basis
0 to
of distri-
RESULTS
plasma
concenpharmacokinetic
Cr#{233}teil,France),
intercepts
an automated
integrated
in RPMI
were
streptomycin,
pendent
1 1 were
and were not significantly
deviation
from nominal
Data
Analysis.
were analyzed
using
of slopes
the
time
volume
concentration
The human
adenocarcinorna
Cells
serum
clinical
program
on
plasma
cx-
function.
from
steady-state
concentration
maintained
compound
<15%.
Pharmacokinetic
tration-time
curves
AUCs
(t,,2),
determined
plasma
pararn-
between
and the log-likelihood
and
2749
89.2 ± 12.4%
in urine,
and 90.0 ±
Recoveries
observed
for the metab-
82.6 and 99.3%
1 1 . The percentage
concentration
the
efficiencies
area
stand-
appropriate
calf
grown
1 1 and SN-38)
in plasma
or
linear
and
from
Calibration
of the
a least
extraction
(CPTAPC)
differences
Cell Cultures.
and the ovarian
pg/ml
of each
injected
of squared
the peak
extended
model
at 37#{176}C
in a humidified
atmosphere
in 5% C02/95%
medium
supplemented
with 10% (w/v) heat-inactivated
Milan,
peak
sum
clearance,
were
Netherlands).
personal
and
homogenate.
weighting
(Lotus
overall
olites ranged
between
different
from CPTvalues
feces
by
proportional
85.3 ± 5.3%
5.0% in feces
with
and
fitted
package
mean
in comparison
in blank
and
software
The
urine
prepared
with
times
to estimate
values
and
squares
evaluated
half-lives
body
to the peak
grown
at cxci-
determination
retention
total
least
Research
graphically.
WiDr
in plasma,
delivered
was
3.0 (Fisons,
ranges of 2-200
ng/ml
(SN-38G,
NPC,
and
in
whereas
in human
on an IBM
quantitative
respectively,
typically
SN-38
monitored
Windows
on HPLC
(V)
curves,
meth-
weighted
were
disposition
bution
and 5 15 nm, respecwith a Chrom-Card
implemented
and
based
was
of 355
processed
Microsoft
qualitative
10-400
effluent
system
under
was
measurements,
ards,
and
column
with
the
(4 X
10 mrvi tetrabutylam-
for other
compounds
The mobile
phase
drug
time
Both
and computed
infinity,
the Neth-
eluted
1 and
perimental
The
at 50#{176}C
Meppel,
isocratically
wavelengths
signal
was
software
compound
2.4
the
and emission
The detector
data
were
value.
methods
mm
the
Darmstadt,
maintained
Holland,
erlands).
column
Merck,
was
(Spark
samples
separations
guard
particle
temperature
column
de(LDC
ODS column
(100 X 4.6
size; LC Service,
Ernmen,
by a LiChroCART
diameter,
The
autosampling
detector
Chromatographic
a Hypersil
5 .am particle
inner
using
least
Beach,
protected
Germany).
the parameter
using
Netherlands),
4 mm
aliquots
were injected
into the HPLC
composed
of a constaMetric
4100
Cancer
as described
peaks
(17),
observed
were analyzed
procedure
was
so that
could
baseline
by our initial
subsequently
resolution
be achieved
into
and
HPLC
rnodi-
of all chro[Fig.
2, A (plas-
2750 Irinotecan
Metabolism
in Humans
A
C
B
10’
34
4
10#{176}
:
1
3#{149}
SC
l0’
102
350
0
350
retention
time
35
0
10
20
30
40
time
Fig. 2 Reversed-phase
HPLC
tracing
with fluorescence
detection
at
excitation
and emission
wavelengths
of 355 and 515 nm of a 250-pA
plasma
extract
taken from a sample
30 mm after iv. infusion
ofCPT-l
I
(A), a 125-pA urine extract
from a sample
collected
during
the first 0-5
h after iv. infusion
of CPT-l
1 (B), and a 25-p.g
fecal extract
from a
sample
collected
during
the first 0-7 h after iv. infusion
ofCPT-ll
(C).
All samples
ing
were obtained
CPT-l
I at a dose
I, SN-38G;
represent:
from a female
level
of
with colorectal
cancer
Fig.
3
Representative
CPT- I I (0)
SN-38
a dose
suspected
380,
and
metabolites
NPC,
(means
±
and
6.95
1 .77
structural
of
nonfluorescent,
polar
of the HPLC
chromatograms
sent
of
parent
of SN-
all
quently,
the relative
4 times
greater
1 .27,
and
fecal
characteristics
en-
any
(EC
or CPT-l
3.2. 1 .3 1) failed
1 metabolite,
its hydrophilic
with
repre-
to release
the exception
glucuroconjugate,
previously
time
the
plasma
studied,
concentration-time
profiles
neously
of CPT-l
the
squares
Powell
analysis
plasma
with
as calculated
Table
1 . Plasma
immediately
by this
summation
cessation
terminal
within
the
same
ously
(22).
The
phase
range
well
rnetabolites
as the parent
below
least
of
l/Y.
model,
for
The
1 1 and
infusion,
as described
input
weighted
are listed
this
course
by
the
two
cyto-
NPC and APC followed
drug, although
concentrations
corresponding
CPT-l
1 levels.
is
previthe
Conse-
be
and
fecal
The
>35
and
The
determined
The
time
most
patients
1 infusion
one patient
because
were
also
dose
in the
only 24.4
excretion
accounted
10 patients.
±
of
13 3%
-52%
for
un-
metabolite
time
de-
course
patient
is depicted
excretion
pattern
-30%
(range,
of the
CPT-1
was
this time,
fecal
of the
1 and its
in Fig. 4, A
virtually
10.7-40.
only
excretion
excreted
1%)
very
was
from
of
little
more
S to 24 h
in 9 of 10 patients.
Data of fecal
were excluded
in the pharmacokiin the study
stool
for only
28.1
Surprisingly,
±
collection.
-56
excretion
10.6%
(mean
fecal
of the dose (Table
of the dose.
As
h after
in either
Alstart
urine
this time period.
of CPT-l
1 and the
± SD)
excretion
2),
in
of the
represented
leading
plasma,
1 could
be distinguished
in urine and feces
as the predominant
species.
SN-38G
was the major
CPT-l
h
increasingly
observed
of
the cumulative
for
start
-25
metabolites.
The
of incomplete
kept
to
terminal
eliminaAs a result of this
principal
of the compounds
administration,
metabolites
up
became
was
the
15 h; after
course
1-2 h after
elimination
with
in the first
calculations
of drug
of
but
for
Overall,
however,
the mean
1 was >40%
larger
than the
urinary
in all 10 patients,
excreted.
SN-38G
Recovery.
for a representative
was
within
or feces is unlikely
to have changed
after
The total cumulative
urinary
excretion
a more
h, which
compound
of
in
1 was
not
of the measured
Fecal
B, respectively.
though
rapidly
followed
of -13.5
iv.
predominating
patients.
CPT-l
metabolites
excreted
peaked
was
urinary
netic
mean
the metab-
1 1 decreased
a half-life
concentration-time
chrome
P-450-mediated
same general
pattern
always
of the
with
zero-order
could
which
cumulative
CPT-l
from
factor
of CPT-
and
after the
excretion
simulta-
phase,
of the AUCs
Urinary
with
fitted
NPC
time,
SN-38G
in plasma
in most
value for unchanged
variable,
for CPT-
of
and
infusion
at
respectively.
to a 1 .75-fold
increased
to CPT- 1 1 and APC.
SN-38,
best
and
triexponential
concentrations
after
prolonged
weighting
parameters
due
relative
the dose
after
profile
#{149}
), APC (U),
of CPT-l
and APC,
APC
3). At this
elimination
identical
versus
for
with
(Fig.
were similar
for the
shown
in Fig. 3. All
algorithm
the
pharmacokinetic
olites,
model
minimization
concentration
were
to a three-compartmental
using
were
The
1 and the metabolites
with a typical
example
profiles
10 patients
of
Disposition.
NPC (
1 by a 90-mm
value
of NPC
consistently
infusion,
half-life
tected
AUC
and
(17).
Plasma
CPT-l
AUC
those
estimate
important
tion
the
of SN-38
as predicted
iv.
conjugated
other
might
the
extended
constituents.
that
(0),
APC.
and
more
from
did not reveal
half-life
postinfusion
mass
spectroscopy
of interference
urinary,
of
positive
plasma
than
All metabolites
and
tandem
resonance
given
time
versus
SN-38G
accurately
in some patients
due to constraints
in sensitivity
the HPLC procedure
(lower
limit of quantitation,
10 ng/ml)
was overall
still within
the same
range
as that observed
CPT-ll
matrices
to obtain
by
the
in any matrix.
In addition,
treatment
of
or isolated
metabolite
peaks
with 1000
3-glucuronidase
drug
from
similar
1 metabolites
aliquots
CPT-l
whole-sample
units
with
1 1 .8 ±
because
Analysis
compounds
0.92,
metabolites
dogenous,
major
in
±
of
standards
identical
magnetic
successful
times
reference
Attempts
the
nuclear
been
retention
were
respectively).
and
yet
of pure
SN-38
identification
not
The
± 0.2 1 , 9.50
mm,
spectrornetry
have
and
APC,
± SD:
28.6
C (feces)].
concentration
and its metabolites
(En) in a single patient
level of 200 mg/m2.
terminal
B (urine),
plasma
(h)
peaks
drug;
5.
SN-38.
ma),
60
receiv-
200 mg/m2.
Chromatographic
3, APC; 4, CPT-l I parent
NPC;
2,
50
(mm)
to a total
unchanged
of all patients
metabolite
in
Clinical
Table
Summary
1
Parameter
CPT-l
1.52
±
0.1 1
Cmax
3.90
±
±
±
±
±
0.484
0.273
0.64
2.06
5.71
3.15
0.62
24.0
t,,(a)
(h)
0.197
t,,,(3)
(h)
(h)
2.35
13.5
t,0(-y)
AUC (p.M . h)
CL (liters/hIm2)
MRT (h)
V,
(liters/m2)
Data
a
25.6
14.0 ±
10.7 ±
138
were
obtained
The parameters
maximum
from
were
calculated
concentration;
t,,2(i),
±
10 cancer
patients
of the
2.32
±
0.475
0.720
2.11
23.5
8.01
±
±
±
±
±
after
by compartmental
half-life
param eters of CPT- I I and m etabolites
SN-38G
Tmax (h)
(ij.M)
o f pharmacokinctic
I
the first
analysis,
2.66
0.057
0.382
0.85
9.67
0.731
treatment
course
phase;
CL,
total
2.86
0.524
0.208
±
± 0.48
± 5.12
± 0.329
of a 90-mm
and data represent
ith disposition
APC
0.47
± 0.019
±
mean
body
iv.
values
clearance;
1.07
±
2.92
15.1
5.90
± 0.96
± 2.30
± 1.20
infusion
MRT,
2751
SN-38
± 0.54
± 0.292
2.08
0.090
0.335
of CPT-
SD. Tm,,,,
±
Research
in plasma”
NPC
0.21
0.265
0.320
0.41
10.6
2.95
Cancer
0.15
0.023
0.183
0.45
± 7.70
± 0.357
0.684
1.34
23.8
1.14
I 1 at a dose
time to maximum
mean
±
±
±
±
residence
time;
level
mg/m2.
Cmax,
volume
of 200
concentration;
V,., steady-state
of distribution.
A
B
40.0
Fig. 4 Representative
urinary
(A) and fecal (B) excretion
versus time profiles of CPT-l 1 (0)
and
its
metabolites
30.0
co
_c,Y:v
,0
0
0
SN-38G
1..
(0),
NPC (#{149}),
APC (U), and
SN-38
(E1) in a single
patient
given
irinotecan
by a 90-mm
iv. infusion
at a dose level of
200 mg/m2.
20.0
C
4
2.0
10.0
/
_/
1r:T
0.0
I
0
urine,
consistent
acid group
rapid renal
only
with
route
of drug
this compound
were
of the dose
excreted
nature
elimination,
unexpectedly
high
in the feces,
reaching
mean
on
(h)
2.45%
The
two
were
cytomainly
percentages
Vitro
Cytotoxicity.
toxic properties
was obtained
noma
and
concentrations
Similar
line
found
mean
bition
of the metabolites
by the exposure
the
inhibition
(14),
data
assay
to be weak
of
of normal
were
cell
KB
human
NPC,
growth
and
and
APC)
(Fig.
to produce
(IGROV-l
2210
epidermoid
proliferation
compound
to various
of S days.
in an analogous
SN-38G,
of cell
each
1850
for APC
the
(i.e.,
inhibitors
concentration
respectively)
using
cell lines
for a period
nM
and
for
WiDr
CPT-l
nsi for SN-38G,
for APC,
indicate
and
that
potent
the
data
(14)
10
and
1610
and
30
time
(h)
with
SN-38.
This
and
1580
these
data
with
demonstrating
substitutions
structure
less
is in line
studies
(bulky)
of the camptothecine
930
Overall,
50
are up to 1000-fold
structure-activity
activity
40
nri for NPC,
APC
metabolite
and
20
nM for SN-38.
3.63
NPC,
active
loss of biological
position
1860
1.54 and
SN-38G,
than
previous
at the C-l0
(23).
DISCUSSION
the cyto-
relative
to CPT-l
1 and SN-38
of the IGROV-l
ovarian
carci-
obtained
all metabolites
into
insight
WiDr
colon
carcinoma
of each test compound
to the recent
growth
Preliminary
flM
0
50
of 1.68
and 5.08% of the dose, respectively,
probably
due to their lower
water solubility
favoring
a hepatobiliary
secretion
pathway.
In
40
1520
of
average,
and APC
total
time
concentrations
with,
NPC
30
with subsequent
of SN-38
was
in the feces.
metabolites
20
of the glucuronic
fecal
unconjugated
P-450-mediated
excreted
polar
and increased
aqueous
solubility
excretion.
Whereas
renal clearance
a minor
chrome
the highly
10
have
and
feces.
described,
of
The
CPT-l
data
for
1 and
complement
the
first
in
previous
of the administered
dose in urine
and bile,
summation
of CPT-ll,
SN-38,
and SN-38G,
The
cell
lines,
and
48 h postinfusion
(24).
substantial
of the dose
abolic
developed
portion
and (intestinal)
specific
This
secretory
analytical
were
gave
able
rise
to recover
pathways.
method
(17)
urine,
of
only
expressed
during
to the
is eliminated
human
the
important
practical
studies
of CPT-l
cell
inhi-
patients
the
plasma,
knowledge
clinical
pharmacology
of CPT-l
1 and have
implications
for its optimal
use. Previous
in cancer
time,
metabolites
metabolism
a 50%
1, 1010
we
cell
were
5).
Here,
pharmacokinetics
as the
the first
hypothesis
through
The
helped
1
25-50%
that
other
met-
use of a recently
to resolve
this
a
2752 Irinotecan
Metabolism
Table
2
in Humans
Cumulative
urinary
and
fecal
excretion
of CPT-
1 1 and
A
metabolites”
Compound
CPT-l
(%)
I
(%)
20.9 ± 7.38
( 12.4-33.4)
3.39 ± 2.31
SN-38G
(0.86-7.
NPC
0.308
13)
0.198
±
1.68
2.80 ± 1.68
(0.853-6.06)
0.389
± 0.260
(0.075-0.807)
SN-38
Total
compounds
28.1
±
0
1.00
II
0.200
±
C.-
(1.49-1.90)
5.08 ± 1.98
(2.28-6.88)
2.45 ± 1.16
(1.45-3.77)
24.4
± 13.3
( I 1.0-38.0)
(0.181-0.735)
APC
1.25
14.9 ± 10.3
(5.68-25.9)
0.317
± 0.306
(0.103-0.678)
10.6
( 1 1 .8-42.2)
0.75
0.50
I.
ci)
0.25
1
0.00
Data were obtained from 10 (urine) or 9 (feces) cancer patients
after the first treatment course of a 90-mm iv. infusion of CPT- 1 1 at a
dose level of 200 mg/m2. The data represent
mean values ± SD, with
ranges in parentheses.
fe, percent of the absolute
CPT- I 1 dose excreted
‘C
as indicated
10-I
10#{176} 10’
102
10
concentration
10
(nM)
drug.
B
l.25
uncertainty,
at least
neously
measure
SN-38,
NPC,
was followed
drug
in human
(b)
and
by cisplatin
liver
statistically
by making
all four principal
SN-38G,
pharmacokinetic
(a)
in part,
metabolites
APC.
administration
on CPT-
agent
Of the
and
greatest
importance
tially
presented
here
versus
time
accurately
profile
for
half-lives
was
of - 13.5
and
the
nential
models
use
underestimated
independent
this
study
models
estimation
and
CPT-l
1 AUC.
in plasma
during
the
formation
APC
parent
rate
and unconjugated
previously
with
(9),
and
The
basis
declined
for
four
to
apply
time
1 1 (and
metabolite)
accounted
Also,
times
The
of
relatively
parallel
decline
suggests
that
Terminal
elimination
limited.
SN-38
were also
CPT-l
1 administered
at a constant
the delayed
SN-38G
elimination
1/4 to 1/30 of
only
high
concomitant
of NPC
detect-
and
very similar,
as a 90-mn
to CPT-l
of
ratio
metabolites
(saturable)
binding
affinity
is
of -7.
the
rel-
plasma
drug.
The
effects,
Our
sites.
severalfold
species,
SN-38.
the contribution
protein
expected
but
processes
proteins
AUC
AUC,
activity,
binding
lower
of the
metabolites
products
on
and
their
in
to preferential
of CPT-l
1 to
reabsorption.
only
predominance
of CPT-l
depends
involve
constituted
a clear
contribution
however,
may
or differences
in addition
indicating
potential
biotransformation
antitumor
understood
elimination
recycling
of SN-38
and conversion
carboxylesterases
during
intestinal
parent
are
completely
for plasma
of the total
active
SN-38G
1 is not
rate-limited
-40%
the
as observed
iv. infusion
to SN-38
ative
biological
APC
elimination
phases
(nM)
ments
Overall,
amount
were
metabolite
of these
accurate
the total
for only
the metabolites
l0
(U), or SN-38 (El), as assessed
by the sulforhodamine
B
Data points, mean values of at least three independent
experiperformed
in quadruplicate;
bars.
SD.
enterohepatic
SN-38
by
kinetic
the
concentration-
that
10’
biexpo-
consistently
to yield dosethe results
of
for
l0
(#{149}),
APC
assay.
which
appropriate
points
10#{176} 10’
10’
Fig. 5 Cell survival
curves of the IGROV-l
ovarian adenocarcinoma
(A) and the WiDr colon carcinoma
cell lines (B) after a 5-day continuous
exposure to different concentrations
of CPT-l 1 (0), SN-38G
(a’), NPC
from Rivory
et a!. (22),
as a single
agent.
Previ-
and failed
28). Thus,
I
-r
concentration
SN-38
from
by terminal
h, respectively,
we observed
in plasma
drug
phase
(27,
of
metabolites
of CPT-l
1 and
characterized
1 disposition
need
CPT-
1 concentrations.
with
all
data
sampling
In our patients,
the total
CPT-l
1 and
have
the
0.25
0.00
concentration
or linear
of NPC
able
plasma
noncompartmental
of complete
profiles.
the
CPT-l
sufficient
ci)
its potenmodel
of simpler
emphasize
with
0.50-
of
activity
to describe
the elimination
parameter
estimates
0.75
no
and
metabolism
antitumor
23.5
are in good agreement
with recent
obtained
with the drug administered
ously,
had
(25);
of CPT-l
1 and
The pharmacokinetic
CPT-l
simultaneously.
The disappearance
the central
plasma
compartment
elimination
the
-t
because:
with cisplatin
to single
kinetic
interaction
(26).
describes
of both
2
C.-
important
likely,
cisplatin
pharmacokinetics
1 treatment
is the disposition
active rnetabolites
in plasma.
CPT-l
very
l.00
to date:
1 1 infusion
1 1 metabolism
1 in clinical
combination
therapy
therapy
did not reveal an apparent
CPT-l
time
not
experiments,
effect
the
CPT-
in this study,
are
microsomal
of
the
0
0
to simulta-
identified
Although
interactions
significant
comparison
it possible
the
of the
1 metabolites
intrinsic
to
activity
concentrations
of
at the
in vitro studies
have
shown
that all metabolites
less potent
than the pharmacologically
active
However,
of CPT-l
it will
(preliminary
plasma
before
drawing
any
1 metabolites
(other
be
essential
data
binding
conclusions
than SN-38)
to determine
are
reported
of the
their
in Ref.
metabolites
on
to
plasma
29).
The
compared
Clinical
with
that
of
SN-38,
which
human
serum
albumin
greater
ability
to interact
binding
sites.
The
addition,
SN-38G
only
metabolites
renal
of
small
APC
clearance
20.9,
estimated
to be
2.93
filtration
of CPT-l
I to plasma
sorbed
nor
extent.
It also
of the
were
proteins
indicates
can
be
metabolic
degradation
value
into
that
is less
in the
that
CPT-l
the
tubular
as much
as -80%
to nonrenal
ing because
of the nonrenal
for by fecal
excretion
of unchanged
it would
likely,
constitute
of CPT-l
by
compounds
and
lites
overall
to the
potentially
renal
microflora-induced
following
biliary
thracycline
important
as yet
nonrenal
of CPT-l
secretion,
11
or,
of the
were
sponding
plasma
tion
these
recently
shown
concentrations
fluids
(35,
36),
are of subordinate
predicted
by
of glucuronic
(17).
pleural
fluid,
than
corre-
lower
suggesting
that excre-
importance.
earlier
studies
acid conjugates
(12,
17),
of CPT-l
there
was no
1 or any other
metabolite
(except
SN-38)
in either urine or feces. This may be
related
to the large size of these molecules
relative
to SN-38,
preventing
them
ferases.
However,
to the fecal
bacterial
metabolites,
may
together
this
1 metabolites
was obtained
with
fecal
concentrations
of SN-38G
interaction
with the glucuronosyltranscaution
has to be exercised
with respect
as endogenous
3-g1ucuronidase
CPT-l
pearance
from
great
expressed
other
enzymes
excreted
from the
(biliary
or enteric)
by the intestinal
have
led to modification
of the
by this route. Indirect
evidence
observation
of unexpectedly
of SN-38
in all nine
accompanied
patients.
by a virtual
This
notion
and
microflora
for
high
AUC
of SN-38
in deriving
tion
side
criteria)
SN-38
ratio.
had also
and
the
Previous
of CPT-l
or penicillin
more
between
as
studies
deSN-38
index
1 and
and
for
systemic
a biliary
of CPT-l
accurate
and
the
ratio
diarrheal
severity
prediction
may
toxicity.
1 with
of diarrhea
This
and
baicalin,
a basis
need
(i.e., the
of the
incidences
et a!.
popu-
(38)
of pretreatment
with the antibiotic
istration
of CPT-l
1 is in progress
for
(40)
1-induced
the modulain light
that
cotreat-
of 3-glucuronidase,
markedly
A clinical
CPT-l
is intensified
coworkers
an inhibitor
streptomycin
in rats.
of
provide
of Takasuna
plus
the
lowest
data suggest
that consideration
of interinof fecal
3-glucuronidase
activity
would
effects
findings
In
relationships
to SN-38G)
of the experienced
ment
homogenates
to be fairly
assist
metabo-
1 within the gut lumen
as observed
with an-
expressed
In all, these
differences
of recent
or
rates,
tract
(38).
to note that the only
diarrhea
graded
>2
toxicity
a correlation
plasma
to be
(30, 33). However,
similar
to recent
findings
by Canal
(39), such a relationship
was not observed
in our patient
of these
Chemical
1 in sweat,
AUCs
of SN-38
pharmacokinetic-dynamic
shown
mechanism
to the intestinal
activity
excretion
sig-
it is thought
injuries
inhibitory
and
adequately
the
controversial,
common
to SN-38
of the
intestinal
is
not respond
of unconjugated
establish
glucuronidation
lation.”
dividual
pathways,
Institute
excretion
1 have
plasma
include
unidentified,
in feces
of CPT-1
Cancer
fecal
product
and
the mitotic
1 1 in( 1).
onset
Although
line with this hypothesis,
it is of interest
patient
in our study experiencing
delayed
CPT-l
leading
surpris-
and does
functional
use
of CPT-
myelosuppresssion
agents.
is still
and
may
to the clinical
toxicities
extent,
1
of the active
by an unexpected
(-60-70%)
from
elimina-
investigation
clearance.
result
to
of the formation
of this compound
concentrations
saliva
As
indication
Further
(12).
other,
and
degradation
or intestinal
stability
In addition,
into
a!.
that
SN-38G
oxidation
to a lesser
to structural
(National
carboxylate
of these
related
highest
antineoplastic
drugs
(34),
is unlikely
to play an
role in the overall
drug elimination,
in view of the
extended
and
from
combinations
incidence
signed
may
and,
2753
CPT-l
in the intestines
respect
dose-limiting
Research
with
concentrations
with
is characterized
fecal
CPT-
the
major
diarrhea
diarrhea
including
nonextractable
of
the contribution
conreab-
in urine
These
resulting
et
dose
unknown
metabolites.
or from
Lokiec
of the
decarboxylation
1, rnetabolites
to quantitate
half
further
after
nucleus
described
required
some
formed
camptothecine
as
that
nonfluorescent
compounds
form
suggest
the
of the overall
1. Part
1 1 . The
Yokokura
SN-38G
ramifications
toxicity
to a great
of CPT-l
dude
The
from
for the observed
studied
processes,
considerable
and
local
released
antidiarrheal
to binding
lumen
have
SN-38
nificant
was
1 is neither
Kaneda
to conventional
than
due
by
mean
clearance,
and the four metabolites,
as suggested
previously
(17),
to a total recovery
of -50%
of the dose. This is highly
more
previously
administered
to rats (37).
The finding
of increased
P-450
The
of the dose-fraction
(-58-68%
attributed
was accounted
cytochrome
in urine.
presumably
suggests
secreted
clearance
may
described
of CPT-
respectively,
body
This
in humans,
and
actively
major
total
liters/h/rn2.
1 1.
studies
in which
(24, 30-33).
In
the product
and
CPT-
3.39%,
detected
,
urine
rate
range),5
and
data of previous
without
cisplatin
1 1 , i.e.
in
glomerular
feces
a
essential
of unchanged
0.389,
NPC
of CPT-
unchanged
tion
to
denote
I or other
excretion
amounts
and
excreted
centration
principally
could
topoisomerase
urinary
very well with the
1 was administered
CPT-l
bound,
globulin.5
metabolite
and
agrees
gamma
with
cumulative
SN-38,
is 94-96%
and
Cancer
ameliorated
the
trial to evaluate
the effects
neornycin
before
at our institute.
the adrnin-
REFERENCES
I. Crecmcrs,
G. J., Lund, B., and Vcrweij, J. Topoisomerase
I inhibitors: topotecan
and irinotecan.
Cancer Treat. Rev., 20: 73-96,
1994.
2. Gcrrits,
C. J. H., de Jonge, M. J. A., Schellens,
J. H. M., Stoter, G., and
Verweij,
J. Topoisomerase
I inhibitors: the relevance of prolonged exposure
for present clinical development.
Br. J. Cancer, 76: 952-962,
1997.
3. Kawato,
Y., Aonuma,
M., Hirota, Y., Kuga, H., and Sato, K. Intracellular
CPT-ll,
4191,
4.
Tsuji,
roles of SN-38,
in the antitumor
a metabolite
effect
of
the
of CPT-l
camptothecin
I. Cancer
Res.,
derivative
51: 4 187-
1991.
T.,
Kaneda,
N.,
Kado,
N.,
Yokokura,
T.,
Yoshimoto
T.,
and
Tsuru, D. CPT- I 1 converting
enzyme from rat serum:
purification
and
some properties.
J. Pharmacobio-dyn.,
14: 341-349,
1991.
5. Rivory.
L. P., Bowlcs,
M. R., Robert I., and Pond, S. M. Conversion
of irinotecan
(CPT-l 1) to its active
metabolite,
7-ethyl-lO-hydroxycamptothecin
Pharmacol.,
(SN-38),
by
52: 1103-1111,
human
1996.
liver
carboxylcstcrase.
Biochcm.
disaphas
been
6
M. J. A. de Jonge,
J. Vcrweij,
P. de Bruijn.
E. Brouwer,
R. H. J.
Mathijsscn,
R. J. van Alphen, M. M. de Boer-Dennert,
C. Jacques. and
A. Sparrcboom.
Pharmacokinetic,
metabolic and pharmacodynamic
profiles in a dose escalating
study of irinotecan
and cisplatin, manuscript
in
5
G. G. Chabot,
Rh#{244}ne-Poulcnc Rorer,
unpublished
data.
preparation.