Article

AMN107 (nilotinib): a novel and selective inhibitor for BCR-ABL

Department of Adult Oncology, Dana Farber Cancer Institute, Boston, MA 02115, USA.
British Journal of Cancer (Impact Factor: 4.84). 06/2006; 94(12):1765-9. DOI: 10.1038/sj.bjc.6603170
Source: PubMed
ABSTRACT
Chronic myelogenous leukaemia (CML) and Philadelphia chromosome positive (Ph+) acute lymphoblastic leukaemia (ALL) are caused by the BCR-ABL oncogene. Imatinib inhibits the tyrosine kinase activity of the BCR-ABL protein and is an effective, frontline therapy for chronic-phase CML. However, accelerated or blast-crisis phase CML patients and Ph+ ALL patients often relapse due to drug resistance resulting from the emergence of imatinib-resistant point mutations within the BCR-ABL tyrosine kinase domain. This has stimulated the development of new kinase inhibitors that are able to over-ride resistance to imatinib. The novel, selective BCR-ABL inhibitor, AMN107, was designed to fit into the ATP-binding site of the BCR-ABL protein with higher affinity than imatinib. In addition to being more potent than imatinib (IC50< 30 nM) against wild-type BCR-ABL, AMN107 is also significantly active against 32/33 imatinib-resistant BCR-ABL mutants. In preclinical studies, AMN107 demonstrated activity in vitro and in vivo against wild-type and imatinib-resistant BCR-ABL-expressing cells. In phase I/II clinical trials, AMN107 has produced haematological and cytogenetic responses in CML patients, who either did not initially respond to imatinib or developed imatinib resistance. Dasatinib (BMS-354825), which inhibits Abl and Src family kinases, is another promising new clinical candidate for CML that has shown good efficacy in CML patients. In this review, the early characterisation and development of AMN107 is discussed, as is the current status of AMN107 in clinical trials for imatinib-resistant CML and Ph+ ALL. Future trends investigating prediction of mechanisms of resistance to AMN107, and how and where AMN107 is expected to fit into the overall picture for treatment of early-phase CML and imatinib-refractory and late-stage disease are discussed.

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AMN107 (nilotinib): a novel and selective inhibitor of BCR-ABL
E Weisberg
1
, P Manley
2
, J Mestan
2
, S Cowan-Jacob
2
, A Ray
1
and JD Griffin
*
,1
1
Department of Adult Oncology, Dana Farber Cancer Institute, 44 Binney Street, Boston, MA 02115, USA;
2
Novartis Institutes of Biomedical Research,
Basel, Switzerland
Chronic myelogenous leukaemia (CML) and Philadelphia chromosome positive (Ph þ ) acute lymphoblastic leukaemia (ALL) are
caused by the BCR-ABL oncogene. Imatinib inhibits the tyrosine kinase activity of the BCR-ABL protein and is an effective, frontline
therapy for chronic-phase CML. However, accelerated or blast-crisis phase CML patients and Ph þ ALL patients often relapse due to
drug resistance resulting from the emergence of imatinib-resistant point mutations within the BCR-ABL tyrosine kinase domain. This
has stimulated the development of new kinase inhibitors that are able to over-ride resistance to imatinib. The novel, selective BCR-
ABL inhibitor, AMN107, was designed to fit into the ATP-binding site of the BCR-ABL protein with higher affinity than imatinib. In
addition to being more potent than imatinib (IC50o30 n
M) against wild-type BCR-ABL, AMN107 is also significantly active against
32/33 imatinib-resistant BCR-ABL mutants. In preclinical studies, AMN107 demonstrated activity in vitro and in vivo against wild-type
and imatinib-resistant BCR-ABL-expressing cells. In phase I/II clinical trials, AMN107 has produced haematological and cytogenetic
responses in CML patients, who either did not initially respond to imatinib or developed imatinib resistance. Dasatinib (BMS-354825),
which inhibits Abl and Src family kinases, is another promising new clinical candidate for CML that has shown good efficacy in CML
patients. In this review, the early characterisation and development of AMN107 is discussed, as is the current status of AMN107 in
clinical trials for imatinib-resistant CML and Ph þ ALL. Future trends investigating prediction of mechanisms of resistance to
AMN107, and how and where AMN107 is expected to fit into the overall picture for treatment of early-phase CML and imatinib-
refractory and late-stage disease are discussed.
British Journal of Cancer (2006) 94, 1765 1769. doi:10.1038/sj.bjc.6603170 www.bjcancer.com
Published online 23 May 2006
& 2006 Cancer Research UK
Keywords: BCR-ABL; AMN107; nilotinib; dasatinib; imatinib-resistance
Chronic myelogenous leukaemia (CML) constitutes 15% of adult
leukaemias, with approximately 4600 newly diagnosed cases per
annum in the United States. The initial, chronic phase of the
disease has a median duration of 4 6 years and is characterised by
overproduction of immature myeloid cells and mature granulo-
cytes in the spleen, bone marrow, and peripheral blood. Without
therapeutic intervention, after a mean latency period of 46 years,
the disease progresses via an accelerated phase, marked by the
presence of primitive blast cells in the bone marrow and peripheral
blood, and finally advances to the ‘blast-crisis’ phase, characterised
by over 30% undifferentiated blasts in the bone marrow and
peripheral blood, and for which median survival is 18 weeks
(Kantarjian and Talpaz, 1988).
The BCR-ABL oncogene, which results from a reciprocal t(9;22)
chromosomal translocation, encodes a chimeric BCR-ABL protein
having constitutively activated Abl tyrosine kinase activity, and is
the underlying cause of CML (Bartram et al, 1983; Groffen et al,
1984; Lugo et al, 1990). The 210 kDa BCR-ABL protein is expressed
in CML patients, whereas a 190 kDa BCR-ABL protein, resulting
from an alternative breakpoint in the BCR gene, is expressed in
Ph þ acute lymphoblastic leukaemia (ALL) patients (Chan et al,
1987).
The discovery that CML is due to the activity of BCR-ABL
prompted the design and development Novartis Pharma AG,
WKL-136.7.86, Klybeckstrasse 141, CH-4057 Basel, Switzerland of
imatinib (Glivec
s
, Gleevect, STI571; Novartis Pharma AG), a
small molecule kinase inhibitor that targets the PDGFR, c-Kit and
Abl kinases (Druker et al, 1996; Buchdunger et al, 2000). Imatinib
provides an effective and durable therapy for CML, inducing
complete haematologic remissions (normal leucocyte count in
peripheral blood) in the majority (98%) of newly diagnosed
patients in the chronic phase of the disease, and complete
cytogenetic responses (no detectable Ph þ cells from X20 bone
marrow cells in metaphase) in a high percentage (86%) of patients
(Simonsson, 2005). Primary resistance to imatinib only occurs
occasionally in chronic-phase CML patients, and recent analysis of
the IRIS study shows a low and decreasing annual rate of
progression (resulting in death) after 1, 2, 3 and 4 years of therapy
of 3.4, 7.5, 4.8 and 1.5%, respectively, possibly as a result of
patients with the worse prognosis progressing relatively early. In
39% of newly diagnosed chronic-phase CML patients, therapy with
a standard dose of imatinib for 12 months leads to a major
molecular response comprising of 1000-fold reduction in BCR-ABL
transcript levels, which is associated with a reduced risk of disease
progression (Hughes et al, 2003). However, advanced (accelerated
or blast crisis) phase CML and Ph þ ALL patients show
significantly decreased response rates to treatment with imatinib
monotherapy, with relapse common within a year (Ottmann et al,
2002; Sawyers et al, 2002); acquired resistance is less commonly
observed in the case of newly diagnosed Ph þ ALL patients
receiving combination therapy with chemotherapy.
Received 15 February 2006; revised 20 April 2006; accepted 21 April
2006; published online 23 May 2006
*Correspondence: Dr JD Griffin; E-mail: James_Griffin@dfci.harvard.edu
Several of the authors are employed by a company (Novartis) whose
product is described in the present work.
British Journal of Cancer (2006) 94, 1765 1769
&
2006 Cancer Research UK All rights reserved 0007 0920/06
$
30.00
www.bjcancer.com
Page 1
Resistance frequently results from the emergence of point
mutations within the kinase domain of the BCR-ABL protein that
reduce the binding affinity of imatinib, although it is occasionally
associated with amplification of the BCR-ABL gene (Gorre et al,
2001). Most mutations that confer resistance to imatinib are
distributed throughout the Abl kinase domain. However, the most
resistant ones, such as many of those found in the P-loop, often
occur at or near residues that are in direct contact with the drug.
The degree of resistance ranges from a few fold for some of the
A-loop mutants, up to complete resistance for the T315I mutation,
which precludes imatinib from binding. Overall, the steady rate
of developing resistance to imatinib has suggested that new
kinase inhibitors could be of clinical value, particularly if they
could override imatinib resistance and bind with higher affinity to
BCR-ABL.
AMN107 (NILOTINIB)
Rational design of novel inhibitors exhibiting effectiveness against
imatinib-resistant mutants of BCR-ABL was carried out by
researchers at Novartis Pharmaceuticals, based upon the crystal
structure of the imatinib-Abl complex (Schindler et al, 2000; Nagar
et al, 2002; Manley et al, 2004). It was hypothesised that the
potency and selectivity of imatinib (Figure 1F) could be improved
by maintaining binding to the inactive conformation of the Abl
kinase domain, but incorporating alternative binding groups to the
N-methylpiperazine moiety, while preserving an amide pharma-
cophore to retain H-bond interactions to Glu286 and Asp381. This
led to the development of AMN107 (nilotinib; Figure 1E), a high-
affinity aminopyrimidine-based ATP-competitive inhibitor that
decreases proliferation and viability of wild-type BCR-ABL- and
imatinib-resistant BCR-ABL mutant-expressing cells in vitro by
selectively inhibiting BCR-ABL autophosphorylation (Table 1).
AMN107 exhibits superior potency to imatinib as an inhibitor of
wild-type BCR-ABL in a wide range of CML-derived and
transfected cell lines (Golemovic et al, 2005; Weisberg et al,
2005). This in vitro profile translates into in vivo efficacy, where
AMN107 has been shown to prolong the survival of mice injected
with BCR-ABL-transformed haematopoietic cell lines or primary
marrow cells, and to prolong survival in imatinib-resistant CML
mouse models (Weisberg et al, 2005).
As well as being designed to bind more tightly to the BCR-ABL
protein in an attempt to enhance efficacy, AMN107 was intended
to over-ride resistance caused by mutations. Crystallographic
studies of AMN107 indeed suggest that subtle differences in the
mode of binding to Abl and a better topological fit to the Abl
protein account for the greater potency of the drug (Weisberg et al,
2005). Like imatinib, AMN107 binds to the inactive conformation
of the Abl tyrosine kinase, with P-loop folding over the ATP-
binding site, and the activation-loop blocking the substrate
binding site, to disrupt the ATP-phosphate-binding site and
inhibit the catalytic activity of the enzyme (Figure 1C) (Manley
et al, 2005). AMN107 makes four hydrogen-bond interactions with
N
O
H
3
C
H
3
CH
3
C
Cl
H
N
N
N
CH
3
CH
3
CH
3
N
HO
H
S
N
N
Met318
Thr315
N
N
N
N
N
O
N
N
H
H
F
F
F
Glu286
Met318
Thr315
Asp381
Met318
Glu286
N
N
N
N
N
O
H
H
N
N
Thr315
Asp381
Ile360
His361
A
B
C
E
D
F
Figure 1 Structures of Abl kinase (A) in the active (Fendrich et al, 2006) and (C) inactive states, with dasatinib (blue) docked and nilotinib (magenta) as
bound in the crystal structure (Weisberg et al, 2005), respectively. The differing conformations of the glycine-rich or P-loop (yellow) and the activation loop
(green) are induced or stabilised by the different binding modes of the two inhibitors. (B) shows a superposition of the two distinct conformations,
emphasising how dasatinib and nilotinib occupy different parts of the cleft between the N- (upper) and C-terminal (lower) lobes of the kinase. The
corresponding aspects of the molecular structures of (D) dasatinib and (E) nilotinib are depicted, with their respective H-bond interactions with the Abl
kinase domain indicated in red, in comparison to imatinib (F).
AMN107 (nilotinib)
E Weisberg et al
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British Journal of Cancer (2006) 94(12), 1765 1769 & 2006 Cancer Research UK
Page 2
the Abl kinase domain (Figure 1E), involving the pyridyl-N and the
backbone-NH of Met318, the anilino-NH and the side-chain
hydroxyl of Thr315, the amido-NH and side-chain carboxylate of
Glu286, as well as the amido-C ¼ O and backbone-NH of Asp381,
to induce the inactive conformation of BCR-ABL (Figure 1C)
(Manley et al, 2005). However, the many lipophilic interactions are
also important for affinity, as is the interaction between the
backbone-C ¼ O of Asp381 and a fluorine atom in the trifluoro-
methyl group of AMN107 (Manley et al, 2005).
AMN107 is X20-fold more potent than imatinib in the killing of
wild-type BCR-ABL-expressing cells (Table 1) (Manley et al, 2005;
O’Hare et al, 2005; Weisberg et al, 2005). Studies involving the
imatinib-sensitive cell lines KBM5 and KBM7 show AMN107 to be
43- and 60 times more potent than imatinib, respectively
(Golemovic et al, 2005). AMN107 maintains activity against
32/33 imatinib-resistant BCR-ABL mutants, but has no significant
activity against the T315I mutant (Table 1) (Manley et al, 2005;
O’Hare et al, 2005; Weisberg et al, 2005). As with imatinib, the lack
of activity against the T315I mutant is the result of AMN107
binding closely to the T315 residue, such that loss of the hydroxyl
side chain and additional methyl group of the isoleucine inhibits
binding (Figure 1E and F).
In a dose-escalating Phase I study, imatinib-resistant CML
patients in the chronic phase (17 patients), accelerated phase (46
patients) and blast crisis (33 patients), together with 13 Ph þ ALL
patients, were treated with AMN107 (50 1200 mg day
1
) for up to
385 days (Kantarjian et al, 2006). The maximum tolerated dose was
determined to be 600 mg b.i.d., with frequently noted side effects
being myelosuppression, mild-moderate skin rash and transient
indirect hyperbilirubinaemia. In this study, AMN107 was not
associated with the oedema frequently associated with imatinib.
Among patients with chronic, accelerated and blast-phase CML,
haematological/cytogenetic responses were achieved in 92/53,
72/48 and 39/27%, respectively. The best responses were seen at
doses X400 mg q.d. and with 400 mg b.i.d. Two of the imatinib-
resistant Ph þ ALL patients also responded. Pharmacokinetic
analysis of patients receiving 400 mg b.i.d., which was the dose
selected for Phase II trials, showed mean peak-trough plasma
levels of 3.6 and 1.7 m
M, respectively, with an apparent half-life of
15 h. Based upon the in vitro data, this level of drug exposure
would be expected to result in clinical activity against most of the
mutants characterised in Table 1, with the exception of T315I, and
is therefore consistent with the responses observed in patients
harbouring imatinib-resistant point mutations.
Table 1 Comparison of imatinib and AMN107 for effects on autophosphorylation and proliferation in Ba/F3 cells transfected to express native BCR-ABL-
or imatinib-resistant mutant forms of the enzyme
Imatinib AMN107
BCR-ABL form (construct) Autophosphorylation Proliferation Autophosphorylation Proliferation
Wild-type p210+IL-3 NA 47700 (4) NA 410000 (15)
Wild-type p210 221731 (14) 678739 (23) 2072 (7) 2571 (68)
M237I (p185) 399 (2) 1545 (2) 4178.3 (3) 4378.7 (3)
M244V (p185) 937 (2) 2036 (2) 101716 (3) 6777 (4)
L248V (p185) 1011 (2) 2081 (2) 8377 (3) 102713 (4)
G250A (p185) 313 (2) 1269 (2) 58711 (3) 6575.6 (3)
G250E (p185) 22877826 (4) 332971488 (2) 92710 (5) 145732 (3)
G250V (p185) 489 (2) 624 (2) 66712 (3) 1971.4 (3)
Q252H (p185) 10807119 (2) 8517436 (2) 117725 (3) 67722 (4)
Y253H (p185) 410000 (2) 47000 (2) 260734 (6) 7007116 (5)
E255D (p185) 754 (2) 1082 (2) 5174.8 (3) 2773.1 (3)
E255K (p185) 48567482 (4) 5567 (2) 392782 (6) 308742 (5)
E255K (p210) 24557433 (4) 71617970 (3) 15379 (4) 548772 (6)
E255R (p185) 1877 (2) 1567 (2) 24076.5 (3) 5874.2 (3)
E255V (p210) 63537636 (14) 61117854 (12) 244722 (13) 791767 (19)
E275K (p185) 1038 (2) 563 (2) 12575.0 (3) 44717.1 (3)
D276G (p185) 1284 (2) 2486 (2) 10779.1 (3) 69710 (3)
E281K (p185) 584 (2) 1601 (2) 4276.5 (3) 4079.8 (3)
K285N (p185) 919 (2) 1264 (2) 204719 (3) 57712 (3)
E292K (p210) 275781 (3) 1552 (2) 3176 (3) 8178 (4)
F311V (p185) 1480 (2) 3535 (2) 8472 (3) 155731 (4)
T315I (p210) 410 000 (22) 47000 (17) 410 000 (48) 410 000 (51)
F317C (p185) 1090 (2) 694 (2) 69713 (3) 2073.1 (3)
F317L (p210) 797792 (11) 15287227 (15) 3874 (13) 9176.5 (17)
F317V (p185) 544747 (3) 5497173 (4) 95728 (3) 2874 (4)
D325N (p185) 584 (2) 887 (2) 7079.0 (3) 2672.7 (3)
S348L (p185) 553 (2) 1370 (2) 5571.3 (3) 2674.8 (3)
M351T (p210) 593757 (11) 16827233 (18) 2973 (13) 3874 (18)
E355A (p185) 676 (2) 1434 (2) 90717 (3) 3576.7 (3)
E355G (p185) 601 (2) 1149 (2) 67715 (3) 4778 (4)
F359C (p185) 1130 (2) 2377 (2) 217717 (3) 258761 (3)
F359V (p185) 1528 (2) 595 (2) 313779 (3) 161761 (4)
A380S (p185) 2617 (2) 3744 (2) 135711 (3) 164727 (3)
L387F (p185) 530 (2) 172 (2) 197725 (3) 4677.2 (3
M388L (p185) 517 (2) 525 (2) 73716 (3) 1872.6 (3)
F486S (p210) 12387110 (11) 30507597 (10) 4174 (8) 7577 (11)
The influence of compounds on kinase autophosphorylation or cell viability was calculated as percentage inhibition as described (Weisberg et al, 2005). Dose response curves
were used to calculate IC
50
values, expressed as mean7s.e.m. (nM) (number of replicates). The influence of compounds on BCR-ABL autophosphorylation or cell viability was
determined with capture ELISAs or the ATPlitet assay kit (Perkin-Elmer), respectively. Dose response curves (per cent inhibition) were used to calculate IC
50
values, expressed
as mean7s.e.m., n ¼ number of experiments.
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E Weisberg et al
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Page 3
The early-phase clinical trials, therefore, support the possibility
that AMN107 will have substantial clinical utility in rescuing
patients who develop imatinib resistance due to point mutations,
and could potentially be used as a single agent in patients at risk
for progression. Additionally, there is growing interest in testing
the hypothesis that administration of multiple Abl kinase
inhibitors in early-phase patients, such as AMN107, dasatinib
(Shah et al, 2005) and imatinib, could be used to delay or prevent
the emergence of drug-resistant clones. In support of these ideas,
additive/synergistic toxicity against both imatinib-sensitive and
imatinib-resistant BCR-ABL-expressing cells has been reported
following coadministration of AMN107 and imatinib, in vitro and
in vivo (Griffin and Weisberg, 2005; Weisberg et al, 2005). Such
effects might result from pharmacodynamic effects, and prelimin-
ary data suggest that synergy between imatinib and AMN107 may
occur at the level of the CML stem cell due to the ability of both
imatinib and AMN107 to inhibit or act as substrates of the
multidrug efflux transporter ABCG2, which confers resistance
toward several anticancer drugs (Jorgensen et al, 2005). A recent
report also suggests that imatinib and AMN107 are taken up in
cells by different mechanisms, with the influx, intracellular
concentrations of imatinib, and consequently patient sensitivity
to imatinib depending upon the organic cation transporter Oct-1,
whereas AMN107 transport appears to be independent of Oct-1
(White et al, 2006). However, since the T315I mutation of BCR-
ABL is highly resistant to imatinib, AMN107 and dasatinib, this
approach needs to be extended to include inhibitors of T315I BCR-
ABL to prevent this mutation from becoming more prevalent.
Alternatively, it is also important to explore the potential for
synergy between AMN107 and other classes of inhibitors that work
through mechanisms not involving inhibition of Abl tyrosine
kinase activity.
To aid the selection of patients most likely to benefit and
show clinical responses to single agents, as well as to assess
which drug combinations might be most appropriate, it is
important to be able to predict resistance mechanisms and
establish the resistance profiles of the available BCR-ABL
inhibitors. Although overexpression of BCR-ABL is a possible
resistance mechanism for AMN107 (Mahon et al, 2004), resistance
is more likely to arise through the emergence of clones expressing
AMN107-resistant mutant forms of BCR-ABL. A cell-based
screening assay designed to predict such mutations has
recently been applied to AMN107 (Von Bubnoff et al, 2006).
Using this system, a reduced pattern of mutations was observed
for AMN107, having some overlap with that seen for imatinib:
Q252H, Y253H, E255K(V), F311I, T315I, S349L and F359I(V), all of
which, with the exception of the T315I mutant, were suppressed at
clinically achievable concentrations of AMN107. In an alternative
cell-line-based mutagenesis study, the emergence of BCR-ABL
mutations resistant to imatinib, AMN107 and dasatinib were
compared: 18 mutations were recovered with imatinib, nine
mutations (G250E, Y253H, E255K(V), E292V, T351I, F359C,
L384M and L387F) were recovered with AMN107, and six
mutations (E255K, L284V, V299L, T315I and F317I(V)) were
recovered with dasatinib (Deininger et al, 2005). In a similar
mutagenesis study with dasatinib (Shah et al, 2005), 10 resistance
mutants of BCR-ABL involving six residues were isolated: L248R,
Q252H, E255K, V299L, F317L/V/I/S and T315I/A. BCR-ABL point
mutations conferring resistance to AMN107 have also been
identified in a random mutagenesis study (Ray et al, 2005). In
this study, 11 novel mutations were detected (K247N, L248V,
L273F, E282K, K285N, V289L, E292K, N297T, H375P, T406I and
W430L), in addition to five (Q252H, Y253C(H), E255K and T315I),
which have been previously observed in CML patients treated with
imatinib. Although these studies do not consistently identify the
same drug-resistant BCR-ABL point mutations for individual
drugs, it is clear that all three compounds display different
mutagenicity profiles.
Since the pattern of arising BCR-ABL mutants should be
associated with the binding mode of that particular compound
to the Abl protein, conceptually, the greatest benefit from a
combination of two such agents should be achieved using
compounds having the greatest difference between their
binding modes. Thus, whereas both imatinib and AMN107 bind
to an inactive conformation of Abl (Figure 1C), dasatinib has
been shown to bind to the active conformation (Figure 1A),
and this can be invoked to explain the differences observed in the
mutagenesis studies with these compounds. Therefore, a combina-
tion between dasatinib and AMN107 (or imatinib) might be
expected to impart the greatest benefit (cf. Figure 1B), since
dasatinib might inhibit many AMN107/imatinib-resistant mutants
and conversely AMN107/imatinib might inhibit many dasatinib-
resistant mutants.
Other studies have uncovered additional targets of AMN107
that help to elucidate its mechanism of action and/or suggest
additional disease targets. Both AMN107 and imatinib have
been observed to promote the expression of Bcl-2-interacting
mediator, a tumour suppressor reported to be underexpressed in
primary CML cells in comparison to normal cells (Aichberger
et al, 2005). The ability of AMN107 to inhibit TEL-platelet-derived
growth factor receptor-beta (TEL-PDGFRbeta), which causes
chronic myelomonocytic leukaemia, and FIP1-like-1-PDGFRalpha,
which causes hypereosinophilic syndrome, suggests potential
use of AMN107 for myeloproliferative diseases characterised
by these kinase fusions (Stover et al, 2005; Weisberg et al,
2005). AMN107 also inhibits the c-Kit receptor kinase, including
the D816V-mutated variant of KIT, at pharmacologically
achievable concentrations, supporting potential utility in
the treatment of mastocytosis, and gastrointestinal stromal
tumours (Weisberg et al, 2005; von Bubnoff et al, 2005; Gleixner
et al, 2006).
CONCLUSION
Preclinical and early-phase clinical findings indicate that
AMN107 may be useful in the treatment of imatinib-refractory
CML. This is due to its strong binding affinity to Abl, its
activity against imatinib-resistant BCR-ABL point mutants, and
its efficacy and tolerability in clinical studies. Greater than 70%
of CML patients with advanced disease and over 90%
of early, chronic-phase patients have responded to AMN107,
and response rates continue to increase with overall good
tolerability. In order to evaluate AMN107 in newly diagnosed
CML, a study has recently been initiated (MD Anderson Cancer
Center, Houston).
The failure of some patients to respond to AMN107, especially
those with more advanced disease, might arise due to development
of new mutations that impede the interaction between AMN107
and BCR-ABL. Thus, the identification and characterisation of
BCR-ABL point mutants conferring resistance to AMN107 will
assist in the prediction of patient responses to AMN107,
identifying combination partners, as well as in the design and
development of novel inhibitors of BCR-ABL that can over-ride
resistance to such mutants. The preclinical and clinical evaluation
of combinations of AMN107 with other approved or investiga-
tional inhibitors of Abl and additional signaling pathways will be
helpful in the development of therapeutic strategies designed to
over-ride drug resistance.
Both the safety and effectiveness of AMN107 are currently being
evaluated in clinical trials involving CML patients that are
intolerant of, or refractory to, imatinib. Thus far, AMN107 is
showing promise as a potential therapeutic for CML at all levels of
the disease. The frequency of use of AMN107 as a treatment for
CML and Ph þ ALL will depend on its safety/efficacy profiles in
clinical trials.
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Page 4
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    • "Previous studies have shown that the specific tyrosine kinase inhibitor imatinib (STI571) [4] and nilotinib (AMN107, trade name Tasigna) [5] are approved for the treatment of CML-AP or CML-BC patients. The second-generation tyrosine kinase inhibitor nilotinib appears to be effective and well-tolerated for those who are resistant to imatinib treatment [6,7] . "
    [Show abstract] [Hide abstract] ABSTRACT: To determine the effects of arsenic trioxide (ATO) and nilotinib (AMN107, Tasigna) alone or in combination on the proliferation and differentiation of primary leukemic cells from patients with chronic myeloid leukemia in the blast crisis phase (CML-BC). Cells were isolated from the bone marrow of CML-BC patients and were treated with 1 μM ATO and 5 nM nilotinib, either alone or in combination. Cell proliferation was evaluated using a MTT assay. Cell morphology and the content of hemoglobin were examined with Wright-Giemsa staining and benzidine staining, respectively. The expression of cell surface markers was determined using flow cytometric analysis. The levels of mRNA and protein were analyzed using RT-PCR and Western blotting, respectively. ATO and nilotinib alone or in combination suppressed cell proliferation in a dose- and time-dependent pattern (P < 0.01 vs. control). Drug treatments promoted erythroid differentiation of CML-BC cells, with a decreased nuclei/cytoplasm ratio but increased hemoglobin content and glycophorin A (GPA) expression (P < 0.01 compared with control). In addition, macrophage and granulocyte lineage differentiation was also induced after drug treatment. The mRNA and protein levels of basic helix-loop-helix (bHLH) transcription factor T-cell acute lymphocytic leukemia protein 1 (TAL1) and B cell translocation gene 1 (BTG1) were both upregulated after 3 days of ATO and Nilotinib treatment. Our findings indicated that ATO and nilotinib treatment alone or in combination greatly suppressed cell proliferation but promoted the differentiation of CML-BC cells towards multiple-lineages. Nilotinib alone preferentially induced erythroid differentiation while combined treatment with ATO preferentially induced macrophage and granulocyte lineage differentiation.
    Full-text · Article · Dec 2015 · Cancer Cell International
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    • "Considering emesis, as well as various medical conditions caused by combination chemotherapy where oral administration of medication is not feasible, initial imatinib dose intensity ≥90% may not be achievable in a significant proportion of patients with newly diagnosed Ph + ALL. Nilotinib, a second generation tyrosine kinase inhibitor, however, showed a better tolerance than imatinib by the upper gastrointestinal tract in patients with CML.[25] Nilotinib is a much more potent BCR-ABL tyrosine kinase inhibitor than imatinib,[26] and might show greater efficacy in leukemia control independent of dose intensity. Alternatively, nilotinib dose intensity may be a limiting factor for effective leukemia control, similar to imatinib. "
    [Show abstract] [Hide abstract] ABSTRACT: The effects of imatinib plus chemotherapy were assessed in 87 patients with newly diagnosed Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL). Imatinib was administered continuously, starting from the eighth day of remission induction chemotherapy, then through 5 courses of consolidation or until allogeneic hematopoietic cell transplantation (HCT). Patients who were not transplanted were maintained on imatinib for 2 years. Eighty-two patients (94.3%) achieved complete remission (CR). Among these 82 CR patients, 40 experienced recurrence of leukemia. The 5-year relapse free survival (RFS) rate and overall survival (OS) rates were 39.0% and 33.4%, respectively. In total, 56 patients underwent allogeneic HCT in first CR. The 5-year cumulative incidence of relapse and OS rate of them was 59.1% and 52.6%, respectively. Six of Seven patients who were maintained on imatinib after completion of consolidation relapsed and the median time of RFS was 40.7 months. In total patient, cumulative molecular CR rate was 88.5% and median time of molecular CR duration was 13 months. Initial imatinib dose intensity was significantly associated with median CR duration (P<0.0001), and overall survival (P=0.002). During the initial phase of treatment of patients with Ph+ ALL, it is important to maintain imatinib dose intensity. This article is protected by copyright. All rights reserved. © 2015 Wiley Periodicals, Inc.
    Full-text · Article · Jul 2015 · American Journal of Hematology
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    • "Imatinib can be used in many types of cancer such as Ph (+) CML, Ph (+) ALL, myelodisplatic disorders, gastrointestinal stromal tumors (GIST) and myeloproliferative disorders by inhibiting Bcr-Abls (123). Nilotinib is a bcr-abl protein blocker and it helps treat CML with Ph (+) chromosome [124]. Pazozanib is used as a treatment for renal cancer [125]. "
    [Show abstract] [Hide abstract] ABSTRACT: Cancer is a disease with uncontrolled division and proliferation of the cells in an organism and is under the influence of genetic and environmental factors but probably the most important factor is human itself. There are more than 100 types of cancer but cancer is also personal. Besides social and economic burden of cancer, patients are affected by side effects of conventional treatments like radiotherapy and chemotherapy. For this reason, scientists are studying on new approaches like gene therapy, cancer vaccines, stem cell therapy, developing tumor specific antibodies, modifying the tumor microenvironment, using miRNAs and immunotherapy which are faster, cheaper, more effective with less side effects. Gene therapy can cure a disease by either making a non-functional gene work again by repairing, replacing, silencing the gene or by killing the tumor cell. Cancer vaccines usually target the tumor and deliver their agent selectively on tumor cells or activate the immune system for tumor cell destruction. Another approach for treatment is the use of oncolytic vectors which target the tumor cells. miRNAs can also be used in cancer treatment by defining the miRNA profiles in body fluids, facilitate the diagnosis and monitoring the process. By modifying the tumor microenvironment, cancer cells can be killed and thus the disease can be cured. The aim of this chapter is to summarize all methods and latest developments in cancer therapy in one combined. It has been focused more on latest technologies and techniques rather than well-known standard therapies. When one wants to learn about cancer, there is more than enough information about therapies, approaches, scientific evidence, superstitions and rumors. It may be necessary to dig deeper to reach the useful knowledge. Generally speaking, books, journals or articles focus on only one or two types of treatment, usually pushing their benefits but only a limited number of publications provide collective data. The reader is usually confused what to search for and what to believe in. This section has been written for the purposes of filling the gap between simple information and extensive complicated data. This chapter summarizes all available treatments and latest developments in a clear and simple language by supporting scientific evidence from latest studies and milestones of therapies and arguing pros et contras of the methods.
    Full-text · Chapter · Jul 2015
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