Kegg Pathway: Chronic myeloid leukemia

Cancer. 2009 Nov 18;
Porkka K, Khoury HJ, Paquette RL, Matloub Y, Sinha R, Cortes JE

BACKGROUND:: Dasatinib, a highly potent BCR-ABL inhibitor, is an effective treatment for patients with Chronic myeloid leukemia in Chronic phase (CML CP) after resistance, suboptimal response, or intolerance to prior imatinib. In a phase 3 dose optimization trial in patients with CML CP (CA180-034), the occurrence of pleural effusion was significantly minimized with dasatinib 100 mg once daily (QD) compared with other treatment arms (70 mg twice daily [twice daily], 140 mg QD, or 50 mg twice daily). METHODS:: To investigate the occurrence and management of pleural effusion during dasatinib treatment, and efficacy in patients with or without pleural effusion, data from CA180-034 were analyzed. RESULTS:: With 24-month minimum follow-up, 14% of patients treated with dasatinib 100 mg QD incurred pleural effusion (grade 3: 2%; grade 4: 0%) compared with 23% to 26% in other study arms. The pleural effusion rate showed only a minimal increment from 12 to 24 months. In the 100 mg QD study arm, median time to pleural effusion (any grade) was 315 days, and after pleural effusion, 52% of patients had a transient dose interruption, 35% had a dose reduction, 57% received a diuretic, and 26% received a corticosteroid. Three patients in the 100 mg QD study arm discontinued treatment after pleural effusion. Across all study arms, patients with or without pleural effusion demonstrated similar progression-free and overall survival, and cytogenetic response rates were higher in patients with a pleural effusion. CONCLUSIONS:: Pleural effusion is minimized with dasatinib 100 mg QD dosing and its occurrence does not affect short- or long-term efficacy. Cancer 2010. (c) 2009 American Cancer Society.

leukemia. 2009 Nov 19;
Puissant A, Colosetti P, Robert G, Cassuto JP, Raynaud S, Auberger P

Imatinib is the leading compound to treat patients with Chronic myelogenous leukemia (CML) but the exact mechanism of its anti-leukemic effect is incompletely elucidated. Through inhibition of BCR-ABL, Imatinib blocks several downstream pathways and induces apoptosis of BCR-ABL positive cells. In this study, we analyzed further the mode of action of Imatinib in different appropriate cellular models of CML either sensitive or resistant to Imatinib and in CD34+ cells from CML patients. Pharmacological or short hairpin RNA-mediated inhibition of BCR-ABL triggers lysosomal membrane permeabilization (LMP) that culminates in activation and redistribution of Cathepsin B (CB) into the cytoplasm of CML cells, in which it triggers directly BCR-ABL degradation. Pharmacological inhibition of CB by CA-074Me or small interfering RNA-mediated knock-down of CB partly protects K562 cells from Imatinib-induced cell death and CB overexpression sensitizes these cells to Imatinib killing. Strikingly, Imatinib-triggered LMP, CB activation and BCR-ABL cleavage in CD34+ cells from CML patients and inhibition of CB confers protection against cell death in clonogenic assays of CD34+ primary cells from CML patients. Hence, we describe an original pathway by which Imatinib participates to the elimination of CML cells through LMP and CB-mediated specific degradation of BCR-ABL.leukemia advance online publication, 19 November 2009; doi:10.1038/leu.2009.233.

Clin Pharmacol Ther. 2009 Nov 18;
Tanaka C, Yin OQ, Sethuraman V, Smith T, Wang X, Grouss K, Kantarjian H, Giles F, Ottmann OG, Galitz L, Schran H

This article describes studies that investigated the pharmacokinetics of nilotinib, a highly specific, oral, second-generation BCR-ABL tyrosine kinase inhibitor. After a once- or twice-daily regimen at doses ranging from 50 to 1,200 mg/day in 119 patients with Chronic myeloid leukemia (CML), the area under the serum concentration-time curve (AUC) and peak serum concentration (C(max)) of nilotinib were found to be nearly dose proportional up to a dose of 400 mg once daily. Solubility-limited absorption at higher doses was observed, but this was partially overcome by dividing the daily dose into two. For instance, the administration of 400 mg nilotinib twice daily resulted in a 35% increase in AUC as compared to a once-daily dose of 800 mg. Exploratory pharmacodynamic assessment showed a general trend of greater reduction in white blood cell (WBC) levels with increase in nilotinib concentrations. This finding was consistent with the observation of an 82% reduction in WBC levels in patients after a regimen of 400 mg nilotinib twice daily for 15 days. The type and quantity of food intake variably affected nilotinib absorption. When administered after a high-fat meal, the AUC of nilotinib increased by 50% in CML patients (n = 10) and by 82% in healthy volunteers (n = 44).

Molecules. 2009; 14(10): 4166-4179
Chang S, Yin SL, Wang J, Jing YK, Dong JH

A series of novel 2-phenylaminopyrimidine (PAP) derivatives structurally related to STI-571 were designed and synthesized. The abilities of these compounds to inhibit proliferation were tested in human Chronic myeloid leukemia K562 cells. (E)-3-(2-bromophenyl)-N-[4-methyl-3-(4-pyridin-3-yl-pyrimidin-2-ylamino)phenyl]acrylamide(12d) was the most effective cell growth inhibitor and was 3-fold more potent than STI-571.

J Neurol Sci. 2009 Nov 16;
Lee G, Xiang Z, Brannagan TH, Chin RL, Latov N

Gene expression analysis previously identified molecular markers that are up-regulated in sural nerve biopsies from patients with Chronic inflammatory demyelinating polyneuropathy (CIDP). To determine whether the same or additional genes are also up-regulated in skin, we applied gene microarray profiling and quantitative real-time PCR (qPCR) analysis to skin punch biopsies from patients with CIDP and controls. Five genes, allograft inflammatory factor 1 (AIF-1), lymphatic hyaluronan receptor (LYVE-1/XLKD1), FYN binding protein (FYB), P2RY1 (purinergic receptor P2Y, G-protein-coupled, 1), and MLLT3 (myeloid/lymphoid or mixed-lineage leukemia translocated to, 3), all associated with immune cells or inflammatory processes, were elevated in punch skin biopsies from patients with CIDP as compared to normal subjects or patients with Charcot-Marie-Tooth Type 1 (CMT1). The average fold change of the 5 genes over normal expression, as determined by qPCR, was significantly elevated in skin biopsies from patients with CIDP in comparison to CMT1 or diabetic neuropathy, and similar to that seen in Lyme disease. The findings indicate the presence of inflammatory changes in the skin of patients with CIDP.

Drug Des Devel Ther. 2009; 3: 89-101
Swords R, Mahalingam D, Padmanabhan S, Carew J, Giles F

Chronic myeloid leukemia (CML) is the consequence of a single balanced translocation that produces the BCR-ABL fusion oncogene which is detectable in over 90% of patients at presentation. The BCR-ABL inhibitor imatinib mesylate (IM) has improved survival in all phases of CML and is the standard of care for newly diagnosed patients in Chronic phase. Despite the very significant therapeutic benefits of IM, a small minority of patients with early stage disease do not benefit optimally while IM therapy in patients with advanced disease is of modest benefit in many. Diverse mechanisms may be responsible for IM failures, with point mutations within the Bcr-Abl kinase domain being amongst the most common resistance mechanisms described in patients with advanced CML. The development of novel agents designed to overcome IM resistance, while still primarily targeted on BCR-ABL, led to the creation of the high affinity aminopyrimidine inhibitor, nilotinib. Nilotinib is much more potent as a BCR-ABL inhibitor than IM and inhibits both wild type and IM-resistant BCR-ABL with significant clinical activity across the entire spectrum of BCR-ABL mutants with the exception of T315I. The selection of a second generation tyrosine kinase inhibitor to rescue patients with imatinib failure will be based on several factors including age, co-morbid medical problems and ABL kinase mutational profile. It should be noted that while the use of targeted BCR-ABL kinase inhibitors in CML represents a paradigm shift in CML management these agents are not likely to have activity against the quiescent CML stem cell pool. The purpose of this review is to summarize the pre-clinical and clinical data on nilotinib in patients with CML who have failed prior therapy with IM or dasatinib.

Drug Des Devel Ther. 2009; 2: 233-243
Fava C, Kantarjian H, Cortes J, Jabbour E

The development of imatinib has resulted in sustained hematologic and cytogenetic remissions in all phases of Chronic myeloid leukemia (CML). Despite the high efficacy, relapses have been observed and are much more prevalent in patients with advanced disease. The most common mechanism of acquired resistance has been traced to Bcr-Abl kinase domain mutations. Several strategies have been developed to overcome the problem of imatinib resistance, including imatinib dose escalation, novel targeted agents and combination treatments. A second generation of tyrosine kinase inhibitors was developed, which displays increased potency towards Bcr-Abl and is able to target the majority of CML mutant clones. Nilotinib (Tasigna((R)), AMN107, Novartis) is a close analog of imatinib with approximately 20-fold higher potency for BCR-ABL kinase inhibition. Preclinical and clinical investigations demonstrate that nilotinib effectively overcomes imatinib resistance, and has induced high rates of hematologic and cytogenetic responses in CML post imatinib failure, with a good tolerance. Nilotinib has been approved for CML patients in Chronic and accelerated phases, post imatinib failure.

Drug Des Devel Ther. 2009; 2: 215-219
Huang X, Patel S, Ahmed N, Seiter K, Liu D

Chronic myeloid leukemia (CML) is characterized by a Philadelphia chromosome which contains an oncogene, bcr-abl. This oncogene encodes a tyrosine kinase which is constitutively activated. Imatinib, a tyrosine kinase inhibitor (TKI), has been widely used in the treatment of CML. Dasatinib and nilotinib were recently approved for the treatment of CML. Other TKIs, such as bosutinib, erlotinib, and sunitinib, are under study for the treatment of CML as well as other hematologic and solid malignancies. Skin rash has been reported as one of the most common side effects of the TKIs. Here we present a case of severe skin rash together with unusual symptoms of high fever and diarrhea induced by imatinib in a CML patient. The dermatologic toxicities from a variety of tyrosine kinase inhibitors are reviewed and general principles of management are also discussed.

Arch Dermatol. 2009 Nov; 145(11): 1313-6
Campbell T, Felsten L, Moore J

BACKGROUND: Gastrointestinal stromal tumors (GISTs) harbor gain-of-function mutations of the c-kit tyrosine kinase receptor. Imatinib mesylate is an inhibitor of c-kit and is indicated in the treatment of Chronic myeloid leukemia and GISTs. Reported adverse effects of imatinib include hypopigmentation, depigmentation, and hyperpigmentation. Although the exact mechanism by which these occur is unclear, it is likely that inhibition of c-kit leads to downstream inhibition of the tyrosinase gene promoter and thus to inhibition of pigment production. OBSERVATIONS: A 45-year-old woman with a history of multiple dysplastic nevi and lentigines was diagnosed as having familial GIST syndrome. Treatment with imatinib mesylate was started in an attempt to decrease the tumor load. Three months after treatment initiation, the patient noted a decrease in the number of pigmented lesions, lightening of the skin in her genital area, and graying of her terminal hair. CONCLUSIONS: The potential association between a specific genetic mutation and pigmentation changes secondary to imatinib therapy may account for the variety in presentation of this potential side effect. Further genetic studies paired with melanocyte-specific or c-kit-specific stains of affected tissue are warranted to better understand the relationship between the genetic mutation and the effect of imatinib on pigmentation.

J Hematol Oncol. 2009 Nov 12; 2(1): 46
Masiello D, Gorospe G, Yang AS

ABSTRACT: Tyrosine kinase inhibitors (TKIs) like dasatinib and nilotinib are indicated as second-line treatment for Chronic myeloid leukemia resistant or intolerant to the current first-line TKI imatinib. These are agents are well tolerated, but potent and as such should be monitored for potentially serious side-effects like fluid retention and pleural effusions. Here we present key clinical trial data and safety considerations for all FDA approved TKIs in context for effective management of fluid retention and pleural effusions. Altering the dasatinib regimen from 70 mg twice daily to 100 mg daily reduces the risk of pleural effusion for patients taking dasatinib. Should pleural effusion develop, dasatinib should be interrupted until the condition resolves. Patients with a history of pleural effusion risk factors should be monitored closely while taking dasatinib. Patients receiving imatinib and nilotinib are not without risk of fluid retention. All patients should also be educated to recognize and report key symptoms of fluid retention or pleural effusion. Pleural effusions are generally managed by dose interruption/reduction and other supportive measures in patients with Chronic myeloid leukemia receiving dasatinib therapy.

Curr Med Res Opin. 2009 Nov 11;
Wu EQ, Johnson S, Beaulieu N, Arana M, Bollu V, Guo A, Coombs J, Feng W, Cortes J

Abstract Background: Patients with Chronic myeloid leukemia (CML) who do not adhere to treatment may experience suboptimal outcomes. Objective: To examine the association between adherence with imatinib and direct healthcare costs and resource utilization in a large group of privately insured CML patients. Patients and methods: CML patients under age 65 were identified with ICD-9 code 205.1X using MarketScan Commercial Claims data between 1/1/02 and 7/31/08. Patients were required to be continuously enrolled in a private insurance plan during the baseline and study periods, defined respectively as the 4 months prior to and the 12 months following imatinib initiation. Non-adherence was evaluated by the medication possession ratio (MPR), defined as the fraction of days during the study period that patients had filled prescriptions for imatinib, and stratified into two groups (low MPR: <85%, high MPR: >/=85%). Costs, inpatient admissions, and hospital days were compared between high and low adherence groups using Wilcoxon tests. Regression models compared utilization and costs controlling for age, sex, CML severity, Charlson comorbidity index, baseline costs, and other factors. Results: The study sample consisted of 592 patients, where 242 (40.9%) patients were classified with a low MPR, while 350 (59.1%) had a high MPR. Mean MPR was 79% (95% confidence interval 76-81%). Patients with a low MPR incurred more all-cause inpatient visits (4.1 vs. 0.4; p < 0.001) and all-cause inpatient days (14.8 vs. 1.8; p < 0.001). Regression models demonstrated a 283% increase (US$56 324; p < 0.001) in non-imatinib costs within the low- vs. high-MPR group. The generalizability of this study is limited by the use of a privately insured population under 65 years of age as well as by the limitations common to claims data analyses. Conclusions: Imatinib adherence is an important issue for patients and physicians. Better imatinib adherence was associated with significantly lower resource utilization and costs in CML patients, as lower imatinib costs in low MPR patients were more than offset by higher non-imatinib costs mostly driven by inpatient services.

FEBS Lett. 2009 Nov 11;
Baruzzi A, Iacobucci I, Soverini S, Lowell CA, Martinelli G, Berton G

Cytoskeleton dynamics are regulated by Src-family tyrosine kinases (SFKs) and c-Abl. We found that the SFK members Hck and c-Fgr regulate tyrosine phosphorylation of c-Abl and c-Abl associates with beta1 integrin-bound Hck or c-Fgr in murine macrophages. Studies with selective inhibitors and cells from SFK-deficient mice showed that c-Abl and SFK regulate migration and activation of the small GTPases Cdc42 and Rac in macrophages. Additionally, human neutrophil chemotactic activity was reduced by c-Abl inhibitors, and neutrophils from Chronic myeloid leukaemia patients displayed an increased chemotactic ability. Hence, Src-family kinase and c-Abl cross-talk in the regulation of myeloid cell migration. STRUCTURED SUMMARY: MINT-7296608: Integrin beta-1 (uniprotkb:P09055) physically interacts (MI:0914) with Hck (uniprotkb:P08103), Abl (uniprotkb:P00520) and Fgr (uniprotkb:P14234) by anti bait coimmunoprecipitation (MI:0006) MINT-7296596: Integrin beta-1 (uniprotkb:P09055) physically interacts (MI:0914) with Fgr (uniprotkb:P14234) and Abl (uniprotkb:P00520) by anti bait coimmunoprecipitation (MI:0006).

Bull Exp Biol Med. 2009 Jul; 148(1): 57-9
Romanouskaya TV, Grinev VV

We compared the cytotoxic effect of 11 flavonoids on Chronic myeloid leukemia (erythroblast crisis) K562 cells and peripheral blood mononuclear cells from healthy donors. Baicalein and myricetin had a specific cytotoxic effect on leukemia cells.

J Clin Oncol. 2009 Nov 9;
Makishima H, Cazzolli H, Szpurka H, Dunbar A, Tiu R, Huh J, Muramatsu H, O'Keefe C, Hsi E, Paquette RL, Kojima S, List AF, Sekeres MA, McDevitt MA, Maciejewski JP

PURPOSE: Acquired somatic uniparental disomy (UPD) is commonly observed in myelodysplastic syndromes (MDS), myelodysplastic/myeloproliferative neoplasms (MDS/MPN), or secondary acute myelogenous leukemia (sAML) and may point toward genes harboring mutations. Recurrent UPD11q led to identification of homozygous mutations in c-Cbl, an E3 ubiquitin ligase involved in attenuation of proliferative signals transduced by activated receptor tyrosine kinases. We examined the role and frequency of Cbl gene family mutations in MPN and related conditions. METHODS: We applied high-density SNP-A karyotyping to identify loss of heterozygosity of 11q in 442 patients with MDS, MDS/MPN, MPN, sAML evolved from these conditions, and primary AML. We sequenced c-Cbl, Cbl-b, and Cbl-c in patients with or without corresponding UPD or deletions and correlated mutational status with clinical features and outcomes. RESULTS: We identified c-Cbl mutations in 5% and 9% of patients with Chronic myelomonocytic leukemia (CMML) and sAML, and also in CML blast crisis and juvenile myelomonocytic leukemia (JMML). Most mutations were homozygous and affected c-Cbl; mutations in Cbl-b were also found in patients with similar clinical features. Patients with Cbl family mutations showed poor prognosis, with a median survival of 5 months. Pathomorphologic features included monocytosis, monocytoid blasts, aberrant expression of phosphoSTAT5, and c-kit overexpression. Serial studies showed acquisition of c-Cbl mutations during malignant evolution. CONCLUSION: Mutations in the Cbl family RING finger domain or linker sequence constitute important pathogenic lesions associated with not only preleukemic CMML, JMML, and other MPN, but also progression to AML, suggesting that impairment of degradation of activated tyrosine kinases constitutes an important cancer mechanism.

Mol Cytogenet. 2009; 2: 21
Al Achkar W, Wafa A, Mkrtchyan H, Moassass F, Liehr T

ABSTRACT: BACKGROUND: The well-known typical fusion gene BCR/ABL can be observed in connection with a complex translocation event in only 2-10% of cases with Chronic myeloid leukemia (CML). As currently most CML cases are treated with Imatinib, variant rearrangements have in general no specific prognostic significance, though the emergence of therapy resistance remains to be studied. RESULTS: Here we report an exceptional CML case with complex chromosomal aberrations not observed before, involving a 5 chromosome translocation implying chromosomal regions such as 1q42, 4p14 and 5q31 besides 9q34 and 22q11.2. CONCLUSION: The reported rearrangement developed most probably in one initial step and had no influence on a good response during Imatinib treatment.

Rev Gastroenterol Peru. 2009 Jul-Sep; 29(3): 239-46
Quispe-Mauricio A, Callacondo D, Rojas J, Zavala D, Posso M, Vaisberg A

INTRODUCTION: The plants have been used as drugs for centuries. However, limited research has been done on its great potential as sources of new therapeutic agents. The purpose of this study was to evaluate Physalis peruviana cytotoxic activity on cell lines HT-29, PC-3, K-562 and VERO. MATERIALS AND METHODS: The HT-29 cell lines, PC-3, K-562 and VERO, were exposed to four concentrations of P. peruviana ethanolic leave and stem extracts, also at different concentrations of cisplatin and 5-fluorouracil (5-FU), which were used as positive controls. We found rates of growth within 48 hours, then we determined the inhibitory concentration 50 (IC50) using linear regression analysis and the index of selectivity of each sample. RESULTS: The P. peruviana ethanolic leave and stem extracts showed cytotoxic activity. The IC50 in g/mL in leaves and stems were, 0.35 (r =-0.95 p <0.025) and 0.37 (r =- 0.90 p <0.05 ) for HT-29; 0.87 (r =-0.98 p <0.01) and 1.01 (r =-0.95 p <0.025) for PC-3; 0.02 (r =-0.98 p <0.01) and 0.03 (r =-0.98 p <0.01) for K-562; 4.9 (r =-0.95 p <0.025) and 6.2 (r =-0.98 p <0.01) for VERO. The IC50 for antineoplastic were: for cisplatin: 4.2 (r =-0.96 p <0.025), 10.3 (r =-0.97 p <0.025), 0.15 (r =-0.98 p = 0.01) and 1.1 (r =- 0.98 p = 0.01); for 5-FU: 2.3 (r =-0.97 p <0.025), 17.9 (r =-0.95 p <0.025), 0.15 (r =-0.98 p = 0.01) and 1.1 (r =-0.94 p = 0.05) for HT-29, PC-3, K562 and VERO respectively. The leaves and stems extracts selectivity index were between 5.6 and 245 for tumor cell lines evaluated, by contrast, cisplatin and 5-FU, only showed values between 0.11 and 7.3. CONCLUSIONS: The P. peruviana leaves and steams ethanolic extracts were more cytotoxic than cisplatin and 5 FU, on the lines HT-29, PC-3 and K562. Furthermore the P. peruviana cytotoxic effects were less than cisplatin and 5-FU for VERO control cells lines.

Chem Biol Drug Des. 2009 Nov 5;
Zhou T, Commodore L, Huang WS, Wang Y, Sawyer TK, Shakespeare WC, Clackson T, Zhu X, Dalgarno DC

Bcr-Abl is the oncogenic protein tyrosine kinase responsible for Chronic myeloid leukemia (CML). Treatment of the disease with imatinib (Gleevec) often results in drug resistance via kinase mutations at the advanced phases of the disease, which has necessitated the development of new mutation-resistant inhibitors, notably against the T315I gatekeeper mutation. As part of our efforts to discover such mutation resistant Abl inhibitors, we have focused on optimizing purine template kinase inhibitors, leading to the discovery of potent DFG-in and DFG-out series of Abl inhibitors that are also potent Src inhibitors. Here we present crystal structures of Abl bound by two such inhibitors, based on a common N9-arenyl purine, and that represent both DFG-in and -out binding modes. In each structure the purine template is bound deeply in the adenine pocket and the novel vinyl linker forms a non-classical hydrogen bond to the gatekeeper residue, Thr315. Specific template substitutions promote either a DFG-in or -out binding mode, with the kinase binding site adjusting to optimize molecular recognition. Bcr-Abl T315I mutant kinase is resistant to all currently marketed Abl inhibitors, and is the focus of intense drug discovery efforts. Notably, our DFG-out inhibitor, AP24163, exhibits modest activity against this mutant, illustrating that this kinase mutant can be inhibited by DFG-out class inhibitors. Furthermore our DFG-out inhibitor exhibits dual Src-Abl activity, absent from the prototypical DFG-out inhibitor, imatinib as well as its analog, nilotinib. The data presented here provides structural guidance for the further design of novel potent DFG-out class inhibitors against Src, Abl and Abl T315I mutant kinases.

Klin Padiatr. 2009 Nov-Dec; 221(6): 351-7
Suttorp M, Claviez A, Bader P, Peters C, Gadner H, Ebell W, Dilloo D, Kremens B, Kabisch H, Führer M, Zintl F, Göbel U, Klingebiel T

PURPOSE: Stem cell transplantation (SCT) can definitely cure Chronic myeloid leukemia (CML), a rare disease in childhood. We prospectively evaluated the results of early SCT in pediatric CML after standardized pretreatment with hydroxyurea+/-interferon. PATIENTS AND METHODS: Between 1995 and 2004, 200 children (median age: 12.4 years) were enrolled and stratified: given the availability of an HLA-matched related donor (MRD), SCT was scheduled within 6 months and otherwise from an unrelated donor (UD) within 12 months following diagnosis. RESULTS: 176 patients underwent SCT; from MRD within median 4 months and from UD within median 11 months after diagnosis. At SCT, 158 patients were in Chronic phase (CP1 or CP2), 9 patients were in accelerated phase and 9 patients were in blast crisis (BC). The conditioning regimen - total body irradiation or busulfan - exerted no different impact on overall survival (OS). Probability of OS at 5 years was 87+/-11% if grafted from a sibling (n=41), 52+/-9% from matched UD (MUD, n=71), and 45+/-16% from mismatched donors (MMD, n=55), respectively. A trend for better OS in CP1 was observed if SCT was performed within 6 months (n=49; 74+/-9%), compared to 7-12 months (n=52; 62+/-15%), and >12 months (n=43; 62+/-17%) after diagnosis, respectively (p=0.157). Probability of relapse at 5 years was 20+/-12%. Transplant-related mortality and graft-versus-host disease mainly contributed to the inferior outcome in UD and HLA-mismatched SCT. CONCLUSION: These data from the first prospective trial on CML restricted to children and adolescents might be considered for decision making when balancing the risks of SCT against the increasing use of imatinib as upfront treatment for CML.

leukemia. 2009 Nov 5;
Rix U, Remsing Rix LL, Terker AS, Fernbach NV, Hantschel O, Planyavsky M, Breitwieser FP, Herrmann H, Colinge J, Bennett KL, Augustin M, Till JH, Heinrich MC, Valent P, Superti-Furga G

Resistance to the BCR-ABL tyrosine kinase inhibitor imatinib poses a pressing challenge in treating Chronic myeloid leukemia (CML). This resistance is often caused by point mutations in the ABL kinase domain or by overexpression of LYN. The second-generation BCR-ABL inhibitor INNO-406 is known to inhibit most BCR-ABL mutants and LYN efficiently. Knowledge of its full target spectrum would provide the molecular basis for potential side effects or suggest novel therapeutic applications and possible combination therapies. We have performed an unbiased chemical proteomics native target profile of INNO-406 in CML cells combined with functional assays using 272 recombinant kinases thereby identifying several new INNO-406 targets. These include the kinases ZAK, DDR1/2 and various ephrin receptors. The oxidoreductase NQO2, inhibited by both imatinib and nilotinib, is not a relevant target of INNO-406. Overall, INNO-406 has an improved activity over imatinib but a slightly broader target profile than both imatinib and nilotinib. In contrast to dasatinib and bosutinib, INNO-406 does not inhibit all SRC kinases and most TEC family kinases and is therefore expected to elicit fewer side effects. Altogether, these properties may make INNO-406 a valuable component in the drug arsenal against CML.leukemia advance online publication, 5 November 2009; doi:10.1038/leu.2009.228.

Blood. 2009 Nov 4;
Vandyke K, Fitter S, Dewar AL, Hughes TP, Zannettino AC

Imatinib mesylate is a rationally designed tyrosine kinase inhibitor that has revolutionised the treatment of Chronic myeloid leukaemia and gastro-intestinal stromal tumours. Although the efficacy and tolerability of imatinib is a vast improvement over conventional chemotherapies, the drug exhibits off-target effects. An unanticipated side-effect of imatinib therapy is hypophosphataemia and hypocalcaemia, which in part has been attributed to drug-mediated changes to renal and gastro-intestinal handling of phosphate and calcium. However, emerging data suggests that imatinib also targets cells of the skeleton, stimulating the retention and sequestration of calcium and phosphate to bone, leading to decreased circulating levels of these minerals. The aim of this review is to highlight our current understanding of the mechanisms surrounding the effects of imatinib on the skeleton. In particular, it examines recent studies which suggest that imatinib has direct effects on bone-resorbing osteoclasts and bone-forming osteoblasts through inhibition of c-fms, c-kit, carbonic anhydrase II and the platelet-derived growth factor receptor. The potential application of imatinib in the treatment of cancer induced osteolysis will also be discussed.