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Medline ® Abstracts for References 1-6

of 'Clinical use of tyrosine kinase inhibitors for chronic myeloid leukemia'

1
TI
Overriding imatinib resistance with a novel ABL kinase inhibitor.
AU
Shah NP, Tran C, Lee FY, Chen P, Norris D, Sawyers CL
SO
Science. 2004;305(5682):399.
 
Resistance to the ABL kinase inhibitor imatinib (STI571 or Gleevec) in chronic myeloid leukemia (CML) occurs through selection for tumor cells harboring BCR-ABL kinase domain point mutations that interfere with drug binding. Crystallographic studies predict that most imatinib-resistant mutants should remain sensitive to inhibitors that bind ABL with less stringent conformational requirements. BMS-354825 is an orally bioavailable ABL kinase inhibitor with two-log increased potency relative to imatinib that retains activity against 14 of 15 imatinib-resistant BCR-ABL mutants. BMS-354825 prolongs survival of mice with BCR-ABL-driven disease and inhibits proliferation of BCR-ABL-positive bone marrow progenitor cells from patients with imatinib-sensitive and imatinib-resistant CML. These data illustrate how molecular insight into kinase inhibitor resistance can guide the design of second-generation targeted therapies.
AD
Division of Hematology and Oncology, Department of Medicine, The David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA.
PMID
2
TI
AMN107, a novel aminopyrimidine inhibitor of p190 Bcr-Abl activation and of in vitro proliferation of Philadelphia-positive acute lymphoblastic leukemia cells.
AU
Verstovsek S, Golemovic M, Kantarjian H, Manshouri T, Estrov Z, Manley P, Sun T, Arlinghaus RB, Alland L, Dugan M, Cortes J, Giles F, Beran M
SO
Cancer. 2005;104(6):1230.
 
BACKGROUND: Previous studies have shown that patients with Bcr-Abl-positive acute lymphoblastic leukemia (ALL) either have primary disease that is refractory to imatinib mesylate or develop disease recurrence after an initial response.
METHODS: The authors investigated the effects of a newly designed Bcr-Abl inhibitor, AMN107, by comparing its in vitro inhibitory potency on p190 Bcr-Abl ALL cell lines with that of imatinib.
RESULTS: In two Philadelphia (Ph)-positive ALL cell lines, AMN107 was found to be 30-40 times more potent than imatinib in inhibiting cellular proliferation. AMN107 was also more effective than imatinib in inhibiting phosphorylation of p190 Bcr-Abl tyrosine kinase in cell lines and primary ALL cells. The inhibition of cellular proliferation was associated with the induction of apoptosis in only one of the cell lines. No activity was observed in cell lines lacking the BCR-ABL genotype.
CONCLUSIONS: The results of the current study suggest the superior potency of AMN107 compared with imatinib in Ph-positive ALL and support clinical trials of AMN107 in patients with Ph-positive ALL.
AD
Department of Leukemia, University of Texas MD Anderson Cancer Center, Houston, 77230, USA.
PMID
3
TI
Characterization of AMN107, a selective inhibitor of native and mutant Bcr-Abl.
AU
Weisberg E, Manley PW, Breitenstein W, Brüggen J, Cowan-Jacob SW, Ray A, Huntly B, Fabbro D, Fendrich G, Hall-Meyers E, Kung AL, Mestan J, Daley GQ, Callahan L, Catley L, Cavazza C, Azam M, Neuberg D, Wright RD, Gilliland DG, Griffin JD
SO
Cancer Cell. 2005;7(2):129.
 
The Bcr-Abl tyrosine kinase oncogene causes chronic myelogenous leukemia (CML) and Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL). We describe a novel selective inhibitor of Bcr-Abl, AMN107 (IC50<30 nM), which is significantly more potent than imatinib, and active against a number of imatinib-resistant Bcr-Abl mutants. Crystallographic analysis of Abl-AMN107 complexes provides a structural explanation for the differential activity of AMN107 and imatinib against imatinib-resistant Bcr-Abl. Consistent with its in vitro and pharmacokinetic profile, AMN107 prolonged survival of mice injected with Bcr-Abl-transformed hematopoietic cell lines or primary marrow cells, and prolonged survival in imatinib-resistant CML mouse models. AMN107 is a promising new inhibitor for the therapy of CML and Ph+ ALL.
AD
Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA.
PMID
4
TI
AMN107 (nilotinib): a novel and selective inhibitor of BCR-ABL.
AU
Weisberg E, Manley P, Mestan J, Cowan-Jacob S, Ray A, Griffin JD
SO
Br J Cancer. 2006;94(12):1765. Epub 2006 May 23.
 
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 inCML 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.
AD
Department of Adult Oncology, Dana Farber Cancer Institute, Boston, MA 02115, USA.
PMID
5
TI
Important therapeutic targets in chronic myelogenous leukemia.
AU
Kantarjian HM, Giles F, Quintás-Cardama A, Cortes J
SO
Clin Cancer Res. 2007;13(4):1089.
 
PURPOSE: Review the state-of-art knowledge of the biology and therapy of chronic myelogenous leukemia (CML).
EXPERIMENTAL DESIGN: A review of the literature was undertaken to summarize current information on the pathophysiology of CML and to update data of imatinib mesylate therapy, mechanisms of resistance, and in vitro and clinical data with the new tyrosine kinase inhibitors.
RESULTS: Imatinib, which targets the ABL kinase activity of BCR-ABL, has prolonged survival in CML. Despite the efficacy of imatinib, some patients in chronic phase and more in advanced phases of CML develop resistance, frequently as a result of BCR-ABL tyrosine kinase domain mutants that impair imatinib binding but retain enzymatic activity. New tyrosine kinase inhibitors inhibit BCR-ABL more potently than imatinib and maintain activity against an array of imatinib-resistant BCR-ABL mutants. The IC(50) values of nilotinib and dasatinib are at least 10- to 100-fold lower for BCR-ABL compared with imatinib. Phase I-II trials of nilotinib and dasatinib showed high activity in imatinib-resistant CML and Philadelphia chromosome-positive ALL. Dasatinib also inhibits membersof the Src family of kinases (SFKs); nilotinib does not. Whether SFKs have a critical role in imatinib resistance or BCR-ABL-mediated oncogenesis is unresolved. Agents that target signals downstream of BCR-ABL (e.g. Ras/Raf and phosphatidylinositol 3-kinase) are under investigation.
CONCLUSIONS: Understanding the pathophysiology of CML and mechanisms of resistance has produced effective targeted strategies for imatinib-resistant CML.
AD
The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, USA. hkantarj@mdanderson.org
PMID
6
TI
Second generation inhibitors of BCR-ABL for the treatment of imatinib-resistant chronic myeloid leukaemia.
AU
Weisberg E, Manley PW, Cowan-Jacob SW, Hochhaus A, Griffin JD
SO
Nat Rev Cancer. 2007;7(5):345.
 
Imatinib, a small-molecule ABL kinase inhibitor, is a highly effective therapy for early-phase chronic myeloid leukaemia (CML), which has constitutively active ABL kinase activity owing to the expression of the BCR-ABL fusion protein. However, there is a high relapse rate among advanced- and blast-crisis-phase patients owing to the development of mutations in the ABL kinase domain that cause drug resistance. Several second-generation ABL kinase inhibitors have been or are being developed for the treatment of imatinib-resistant CML. Here, we describe the mechanism of action of imatinib in CML, the structural basis of imatinib resistance, and the potential of second-generation BCR-ABL inhibitors to circumvent resistance.
AD
Dana Farber Cancer Institute, Mayer 540, 44 Binney Street, Boston, MA 02115, USA.
PMID