Long-Term Mutation Follow-up of Philadelphia-Chromosome Positive Leukemia Patients Treated with Second-Generation Tyrosine Kinase Inhibitors after Imatinib Failure Shows That Newly Acquired Bcr-Abl Kinase Domain Mutations Leading to Relapse Are Mainly Detected during the First Year.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 2118-2118 ◽  
Author(s):  
Simona Soverini ◽  
Alessandra Gnani ◽  
Sabrina Colarossi ◽  
Fausto Castagnetti ◽  
Francesca Palandri ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Median Time ◽  
Kinase Inhibitors ◽  
Initial Response ◽  
Kinase Domain ◽  
Abl Kinase ◽  
Imatinib Resistant ◽  
Tki Treatment ◽  
Selection Of

Abstract Resistance to imatinib in Philadelphia-positive (Ph+) leukemia patients is often associated with selection of point mutations in the Bcr-Abl kinase domain (KD). Dasatinib and nilotinib are second-generation tyrosine kinase inhibitors (TKIs) with different binding modes with respect to imatinib, that have been shown to confer in vitro and in vivo activity against many Bcr-Abl mutated forms. However, both dasatinib and nilotinib have been shown to retain some ‘Achilles heels’, and they include both imatinib-resistant mutations (e.g., T315I) and some novel, inhibitor-specific ones. Selection of either type of KD mutations has frequently been observed in patients (pts) who relapse after an initial response to dasatinib or nilotinib and represents one of the major hurdles on the road to successful treatment of imatinib-resistant pts. We have monitored Abl KD mutation status in a total of 121 pts who received dasatinib (n= 78) or nilotinib (n=43) as 2nd TKI after imatinib failure since February 2005. Fifty-eight (48%) pts had chronic phase (CP) chronic myelogenous leukemia (CML), 63 pts (52%) had accelerated phase (AP) or blast crisis (BC) CML or Ph+ acute lymphoblastic leukemia (ALL). Median age was 55 years (range, 18–76); median time from diagnosis was 49 months (range, 4–181); median time on imatinib was 32 months (range, 4–66). Median follow-up of all pts who received a 2nd TKI is 7 months (range, 1–38). Median follow-up of pts who are still on 2nd TKI treatment is 32 months (range, 28–38). Relapses after an initial response have so far been observed in 46/121 pts. Thirty-eight out of these 46 pts had AP/BC CML or Ph+ ALL at the time 2nd TKI was started. Forty-one out of 121 (34%) pts have experienced relapse after an initial response during the first 12 months of 2nd TKI treatment (median time to relapse, 6,5 months; range 4–12 months), while only five of the 45 (11%) pts who were still on 2nd TKI treatment after >12 months have relapsed (at 13, 15, 18, 20 and 33 months, respectively). Interestingly, none of these 5 pts had never achieved more than a minor cytogenetic response (CgR), and 4/5 pts were receiving a reduced TKI dose because of toxicity. In 36/46 (78%) cases, relapse was associated with newly acquired Abl KD mutations. In particular 26/30 (87%) pts who relapsed on dasatinib and 10/16 (63%) pts who relapsed on nilotinib had evidence of a newly acquired KD mutation presumably responsible for treatment failure. Newly acquired mutations in pts who relapsed on dasatinib as 2nd TKI were T315I (n= 12 pts) F317L (n= 8 pts) T315A (n=3 pts); V299L (n=3 pts); F317I (n=2 pts); 2 pts had multiple mutations. Newly acquired mutations in pts who relapsed on nilotinib as 2nd TKI were E255K (n=3); E255V (n=2); Y253H (n=2); T315I (n=1); F359V (n=1); F359C (n=1). Sixteen pts (but none of those harboring the T315I) switched to dasatinib or nilotinib or high-dose imatinib as 3rd TKI and this rescued hematologic or even cytogenetic responses in a proportion of cases. Our observations suggest that: newly acquired mutations leading to relapse in Ph+ leukemia pts receiving dasatinib or nilotinib as 2nd TKI usually arise rapidly; the likelihood of mutation selection consistently decreases over time, and seems mainly confined to advanced phase pts and to pts with no or minor CgR; almost all (87%) cases who developed resistance to dasatinib had newly acquired KD mutations - suggesting that the higher potency with respect to imatinib can overcome Bcr-Abl gene amplification and that Src kinase inhibition may turn off Bcr- Abl-independent resistance mechanisms; a lower incidence (63%) of newly acquired KD mutations was observed in pts who developed resistance to nilotinib; with the exception of T315I, there is little if no overlap between dasatinib and nilotinib-resistant mutants, which may allow to regain responses by switching TKIs.

Philadelphia-positive patients who already harbor imatinib-resistant Bcr-Abl kinase domain mutations have a higher likelihood of developing additional mutations associated with resistance to second- or third-line tyrosine kinase inhibitors

Blood ◽  
2009 ◽  
Vol 114 (10) ◽  
pp. 2168-2171 ◽  
Author(s):  
Simona Soverini ◽  
Alessandra Gnani ◽  
Sabrina Colarossi ◽  
Fausto Castagnetti ◽  
Elisabetta Abruzzese ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Tyrosine Kinase Inhibitors ◽  
Kinase Inhibitors ◽  
Sequential Therapy ◽  
Initial Response ◽  
Kinase Domain ◽  
Imatinib Resistance ◽  
Mutation Status ◽  
Abl Kinase ◽  
Imatinib Resistant

Abstract Dasatinib and nilotinib are tyrosine kinase inhibitors (TKIs) developed to overcome imatinib resistance in Philadelphia-positive leukemias. To assess how Bcr-Abl kinase domain mutation status evolves during sequential therapy with these TKIs and which mutations may further develop and impair their efficacy, we monitored the mutation status of 95 imatinib-resistant patients before and during treatment with dasatinib and/or nilotinib as second or third TKI. We found that 83% of cases of relapse after an initial response are associated with emergence of newly acquired mutations. However, the spectra of mutants conferring resistance to dasatinib or nilotinib are small and nonoverlapping, except for T315I. Patients already harboring mutations had higher likelihood of relapse associated with development of further mutations compared with patients who did not harbor mutations (23 of 51 vs 8 of 44, respectively, for patients who relapsed on second TKI; 13 of 20 vs 1 of 6, respectively, for patients who relapsed on third TKI).

Outcome of Patients (pts) with Chronic Myeloid Leukemia (CML) After Failure to 2nd and 3rd Tyrosine Kinase Inhibitors (TKIs)

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 1238-1238
Author(s):  
Liunan Li ◽  
Hagop Kantarjian ◽  
Meng Zhao ◽  
Susan O'Brien, MD ◽  
Elias Jabbour ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Patient Population ◽  
Kinase Inhibitors ◽  
Chronic Phase ◽  
Cytogenetic Response ◽  
Kinase Domain ◽  
Abl Kinase ◽  
Kinase Domain Mutations ◽  
Lost To Follow Up

Abstract Abstract 1238 Background: First and second generation tyrosine kinase inhibitors are effective for most pts with CML in chronic phase. Approximately 80% of pts achieve complete cytogenetic response (CCyR) with imatinib, but nearly 15% of them eventually lose response. With dasatinib, nilotinib or bosutinib, approximately 50% of those who failed imatinib achieve CCyR, and about 15% of them eventually lose response. Using one of these agents after failure to 2 prior TKIs results in CCyR in only about 20%, usually of short duration. Thus, some pts receive and fail therapy with 3rd TKI. No standard therapy is available for these pts. Although their outcome is presumed to be poor, this has not been systematically analyzed. Understanding their outcome is important since new investigational options are being developed to treat this patient population, and understanding their expected outcome is needed to better comprehend the results obtained. Aim: To analyze the outcome of patients who have received and failed 2nd and 3rd TKI. Methods: We reviewed the records of 64 CML pts treated at MD Anderson Cancer Center from 2005–2009 who received treatment with 3 sequential TKIs. The second TKI was bafetinib (INNO-406, 1pt), bosutinib (12 pts), dasatinib (13 pts), and nilotinib (38 pts). Upon failure to 2nd TKI, 27 pts were in chronic (CP), 20 pts in accelerated (AP), 14 pts in blast phase (BP), and 3 pts in 2nd chronic phase, and were started on a 3rd TKI: bafetinib (6 pts), bosutinib (12 pts), dasatinib (35 pts), and nilotinib (11 pts). Results: After a median follow-up of 36 months (mo) (range, 3 – 71), 14 (22%) pts were still on 3rd TKI, including nilotinib (4 pts), dasatinib (7 pts), bafetinib (1 pt), and bosutinib (2 pts). Fifty (78%) pts failed therapy, including 16 pts (1 in 2nd CP, 2 in CP, 4 in AP, and 9 in BP) died during therapy with 3rd TKI. Among the 34 pts alive after 3rd TKI failure, their median age was 59 years (range, 19 to 92), and 17 were female. Their median time from diagnosis of CML was 76 mo (22 to 241). They failed the 3rd TKI after a median of 5.8 mo (range, 0.3 to 45) on therapy, with 27 pts being resistant (1 had minor cytogenetic response, all others 100% Ph+) and 7 pts were intolerant to 3rd TKI. The best response to a 3rd TKI was 1 partial cytogenetic (PCyR), 1 minor and 1 minimal cytogenetic response, 7 complete hematologic responses (CHR), and 24 with no response (NR). Upon failure to 3rd TKI, 16 pts were in CP (4 with BCR-ABL kinase domain mutations including two F359V, and one Y253H and one F317L), 11 in AP (6 with BCR-ABL kinase domain mutations including two G250E, and one each for F317L, F359C, T315I, and F317L), and 7 in BP (3 pts with BCR-ABL kinase domain mutations, two T315I and one V299L). These stages at the end of 3rd TKI represented no stage change in 26 patients, a progression in 5 pts (3 from CP to AP, 1 from CP to BP, 1 from AP to BP), and an improvement in 3 (from AP to CP in 2, from BP to AP in 1). Of those in CP, 16 pts were in complete hematologic responses (CHR). The median Ph+ metaphase after failure to 3rd TKI was 94% (8 to 100). After failure to 3rd TKI, 4 pts received dasatinib, 5 nilotinib, 4 bafetinib, 2 AP24534, 3 omacetaxine + imatinib, 6 single-agent omacetaxine, 4 stem cell transplantation, and 1 each for MK-0457, hydroxyurea, vincristine + deaxmethasone, idarubicin + imatinib + Ara-C, and DCC-2036. One pt was lost to follow-up. Response to subsequent therapy is described in the table 1 . After a median follow-up of 4 mo since failure to 3rd TKI, 15 of 34 pts have died, including 4 of 16 in CP, 5 of 11 in AP, and 6 of 7 in BP. The median survival from failure to 3rd TKI was 25 mo (12 mo for pts in CP, 6 in AP, and 1 in BP). Among patients who are still alive, 12 pts are still receiving the 4th therapy which were 3 pts received nilotinib, 2 dasatinib, 2 homoharringtonine, 2 AP245341, 1 bafetinib, 1 DCC-2036, and 1 hydroxyurea since failure to 3rd TKI, and 6 pts have changed to subsequent therapies after 4th therapy, including 5 pts on AP24534, 1 pt on XL228, and one lost to follow-up. Conclusions: Patients who have failed therapy with 2nd and 3rd TKI have a very poor prognosis with rare responses and a very short expected survival. New therapies that may improve their outcome and prolong their survival are urgently needed for this patient population. Disclosures: No relevant conflicts of interest to declare.

BCR-ABL kinase domain mutation analysis in chronic myeloid leukemia patients treated with tyrosine kinase inhibitors: recommendations from an expert panel on behalf of European LeukemiaNet

Blood ◽  
2011 ◽  
Vol 118 (5) ◽  
pp. 1208-1215 ◽  
Author(s):  
Simona Soverini ◽  
Andreas Hochhaus ◽  
Franck E. Nicolini ◽  
Franz Gruber ◽  
Thoralf Lange ◽  
...  
Keyword(s):  
Chronic Myeloid Leukemia ◽  
Tyrosine Kinase ◽  
Tyrosine Kinase Inhibitors ◽  
Mutation Analysis ◽  
Myeloid Leukemia ◽  
Kinase Inhibitors ◽  
Direct Sequencing ◽  
Chronic Phase ◽  
Kinase Domain ◽  
Abl Kinase

AbstractMutations in the Bcr-Abl kinase domain may cause, or contribute to, resistance to tyrosine kinase inhibitors (TKIs) in chronic myeloid leukemia patients. Recommendations aimed to rationalize the use of BCR-ABL mutation testing in chronic myeloid leukemia have been compiled by a panel of experts appointed by the European LeukemiaNet (ELN) and European Treatment and Outcome Study and are here reported. Based on a critical review of the literature and, whenever necessary, on panelists' experience, key issues were identified and discussed concerning: (1) when to perform mutation analysis, (2) how to perform it, and (3) how to translate results into clinical practice. In chronic phase patients receiving imatinib first-line, mutation analysis is recommended only in case of failure or suboptimal response according to the ELN criteria. In imatinib-resistant patients receiving an alternative TKI, mutation analysis is recommended in case of hematologic or cytogenetic failure as provisionally defined by the ELN. The recommended methodology is direct sequencing, although it may be preceded by screening with other techniques, such as denaturing-high performance liquid chromatography. In all the cases outlined within this abstract, a positive result is an indication for therapeutic change. Some specific mutations weigh on TKI selection.

Co-Crystal Structures of 7-Azaindole Inhibitors of Wild-Type and T315I Imatinib-Resistant Mutant Forms of the BCR-ABL Tyrosine Kinase.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 1018-1018
Author(s):  
Hal A. Lewis ◽  
Fred Zhang ◽  
Richard Romero ◽  
Pierre-Yves Bounaud ◽  
Mark E. Wilson ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Tyrosine Kinase ◽  
Crystal Structures ◽  
Kinase Domain ◽  
Hinge Region ◽  
Wild Type ◽  
X Ray ◽  
Abl Kinase ◽  
Imatinib Resistant ◽  
Mutant Forms

Abstract Chronic myelogenous leukemia (CML) arises from uncontrolled cell growth driven by a constitutively active BCR-ABL fusion protein tyrosine kinase, which is the product of the pathognomonic Philadelphia chromosomal translocation. Imatinib mesylate (Gleevec) is a BCR-ABL inhibitor used as a first line treatment of CML. Although imatinib is highly effective in chronic phase CML, in advanced disease patients frequently relapse due to the emergence of drug resistance. Approximately two-thirds of resistance is caused by point mutations in the BCR-ABL kinase domain, which give rise to active mutant forms of the enzyme that are insensitive to Gleevec. The T315I mutation represents one of the most common causes of resistance, is resistant to the second generation BCR-ABL inhibitors dasatinib and nilotinib, and represents an important and challenging target for discovery of next generation targeted CML treatments. We have applied X-ray crystallographic screening of our FAST™ fragment library and structure-guided hit-to-lead optimization to identify potent inhibitors of both wild-type and T315I mutant BCR-ABL. These efforts yielded a 7-azaindole compound series that exhibits binding to and inhibition of both wild-type and T315I BCR-ABL. Methods: Wild-type (with Y393F) and T315I Abl kinase domain protein were expressed in E. coli and purified to homogeneity. These proteins were crystallized in the presence of a reference inhibitor followed by addition of the 7-azaindole series compounds soaked into the preformed crystals to displace the reference compound, giving the desired co-crystal. X-ray diffraction data were recorded at the company’s proprietary synchrotron beamline SGX-CAT at the Advanced Photon Source. Three-dimensional enzyme-inhibitor co-crystal structures were determined by molecular replacement and refined to permit modeling of bound ligand. Results: Both wild-type and T315I Abl structures revealed enzyme in the active conformation with inhibitors bound to the kinase hinge region. The crystal structure of 2-amino-5-[3-(1-ethyl-1H-pyrazol-5-yl)-1H-pyrrolo[2,3-b]pyridin-5-yl]-N,N-dimethylbenzamide in complex with T315I, illustrates the typical binding mode which is independent of the 315 residue, and therefore accounts for the compound inhibiting the T315I mutant form of BCR-ABL (see figure). The inhibitor binds to the hinge region of ABL utilizing hydrogen bonding to backbone carbonyl of Glu316 and NH of Met318, with the pyrazole ring stacking in a lipophilic pocket between Phe382 and Tyr253. In addition, the benzamide carbonyl participates in a hydrogen bond interactioin with the backbone-NH of Glu249 of the p-loop. Conclusions: X-ray crystallographic fragment screening and co-crystal structure studies have been successfully employed in discovery/optimization of 7-azaindole series compounds, yielding potent, selective inhibitors of both wild-type and imatinib-resistant forms of BCR-ABL. Figure Figure

Treating Ph+ Acute Lymphoblastic Leukemia (ALL) in the Elderly: The Sequence of Two Tyrosine Kinase Inhibitors (TKI) (Nilotinib and Imatinib) Does Not Prevent Mutations and Relapse.

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 2601-2601 ◽  
Author(s):  
Cristina Papayannidis ◽  
Paola Fazi ◽  
Alfonso Piciocchi ◽  
Francesco Di Raimondo ◽  
Giovanni Pizzolo ◽  
...  
Keyword(s):  
Acute Lymphoblastic Leukemia ◽  
Tyrosine Kinase ◽  
Research Funding ◽  
Kinase Inhibitors ◽  
Lymphoblastic Leukemia ◽  
The Elderly ◽  
Kinase Domain ◽  
Intensive Chemotherapy ◽  
Molecular Responses ◽  
Abl Kinase

Abstract Abstract 2601 Background: Tyrosine Kinase Inhibitors (TKI) have been shown to be very effective for the treatment of Acute Lymphoblastic Leukemia (ALL), with a Complete Hematologic Remission (CHR) rate close to 100%, and a high rate of Complete Cytogenetic and Molecular responses (CCgR and CMR). However, when they are used alone, as single agents, most patients relapse, so that they are currently used in combination with chemotherapy and as a preparation to allogeneic stem cell transplantation (SCT). Since Ph+ ALL is more frequent in the elderly, many patients cannot tolerate intensive chemotherapy and are not eligible for SCT. We have explored if the administration of two TKIs, Nilotinib (NIL) and Imatinib (IM) can improve the results without increasing the toxicity. Aims: To evaluate the response and the outcome of Ph+ ALL patients treated with the sequential administration of NIL and IM, to investigate the type and number of BCR-ABL kinase domain mutations developing during and after the study. Methods: We have designed a study (ClinicalTrials.gov. NCT01025505) in which patients more than 60 years old or unfit for intensive chemotherapy and SCT where treated with two TKIs, NIL 400 mg twice daily, and IM 300 mg twice daily, alternating for 6 weeks for a minimum of 24 weeks (study core) and indefinitely in case of response. The 6-weeks rotation schedule was respected, irrespectively of temporary discontinuations. The primary end-point was the rate of Disease Free Survival (DFS) at 24 weeks (4 courses of treatment); the secondary end points included the evaluation of CHR, CCgR and CMR rates. Mutation analysis was performed by nested RT-PCR amplification of the ABL kinase domain of the BCR-ABL transcript (codons 206 through 421). Amplified products were screened by denaturing-high performance liquid chromatography (D-HPLC). Samples scored positive for the presence of sequence variations were then subjected to direct automatic sequencing to characterize the mutation. Results: 39 patients have been enrolled in 15 Italian hematologic Centers (median age 66 years, range 28–84). Among these, 8 patients were unfit for standard chemotherapy or SCT (median age 50 years, range 28–59). 27 patients were p190, 5 were p210 and 7 were p190/p210. After 6 weeks of treatment, 36 patients were evaluable for response: 34 were in CHR (94%) and 2 in PHR (6%). 23 patients have already completed the study core (24 weeks), 87% were in CHR and 17 are currently continuing therapy in the protocol extension phase. Thus, the OS at 1 year is 79%, and 64% at 2 years. Overall, 1 patient was primarily resistant and 13 patients have relapsed, with a median time to relapse of 7.6 months (range 0.8–16.1 months), for a DFS of 51.3% at 12 months (Figure 1). Mutations detected were T315I in 2 cases, Y253H in 3 cases, T315I and Y253H in 1 case, E255K in 1 case, T315I and E255K in 1 case, E255V and Y253H in 1 case. Two patients were WT. A detailed kinetics of Molecular responses is shown in Table 1. Data on mutational analysis are reported in Table 2. Further details about Cytogenetic and Molecular responses, and about Adverse Events will be provided on site. Conclusions: In this small cohort of Ph+ ALL elderly/unfit patients, the rates of relapse and progression were not likely to be different from the rates observed with Imatinib alone (Vignetti et al, Blood 2007, May 1;109(9):3676-8) and Dasatinib alone (Foà, Blood 2011, Dec 15;118(25):6521-8). It's important to notice that the mutations that occurred at the time of relapse were sensitive to other TKIs (Dasatinib and Ponatinib). Acknowledgments: COFIN, Bologna University, BolognAIL, PRIN, Fondazione del Monte di Bologna e Ravenna, INPDAP. Disclosures: Pizzolo: Hoffmann-La Roche: Consultancy, Honoraria. Luppi:CELGENE CORPORATION: Research Funding. Vallisa:CELGENE CORPORATION: Research Funding. Martinelli:NOVARTIS: Consultancy, Honoraria, Speakers Bureau; BMS: Consultancy, Honoraria, Speakers Bureau; PFIZER: Consultancy; ARIAD: Consultancy. Baccarani:ARIAD, Novartis, Bristol Myers-Squibb, and Pfizer: Consultancy, Honoraria, Speakers Bureau.

Dissecting the Complexity of Philadelphia-Positive Mutated Populations by Ultra-Deep Sequencing of the Bcr-Abl Kinase Domain: Biological and Clinical Implications

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 692-692 ◽  
Author(s):  
Simona Soverini ◽  
Caterina De Benedittis ◽  
Katerina Machova Polakova ◽  
Adela Brouckova ◽  
Fausto Castagnetti ◽  
...  
Keyword(s):  
Deep Sequencing ◽  
Research Funding ◽  
Kinase Inhibitor ◽  
Lymphoblastic Leukemia ◽  
Kinase Domain ◽  
Mutation Status ◽  
Abl Kinase ◽  
Selection Of ◽  
Higher Sensitivity

Abstract Abstract 692 Background and Aims: In chronic myeloid leukemia (CML) and Philadelphia-positive acute lymphoblastic leukemia (ALL), tyrosine kinase inhibitor (TKI) therapy may select for drug-resistant Bcr-Abl mutants. Mutation status of resistant patients is usually investigated by Sanger sequencing (SS) of the Bcr-Abl kinase domain (KD). Novel ultra-deep sequencing (UDS) technologies allow to conjugate higher sensitivity with the unprecedented possibility to perform instant cloning of thousands of DNA molecules. We thus decided to take advantage of an UDS-based approach in order to: Methods: We retrospectively performed a longitudinal analysis of a total of 111 samples from 35 CML or Ph+ ALL patients who had received sequential treatment with multiple TKIs (two to four TKIs among imatinib, dasatinib, nilotinib, ponatinib) and had experienced sequential relapses accompanied by selection of TKI-resistant mutations. All samples had already been scored by SS; 74/111 (67%) were positive for one (n=33) or multiple (n=41) mutations. UDS of the Bcr-Abl KD was done using Roche 454 technology. UDS allowed to achieve a lower detection limit of at least 0.1% – as compared to 20% of SS. Results: Bcr-Abl KD mutation status was found to be more complex than SS had previously shown in 85/111 (77%) samples (representative examples are detailed in Table 1). In 33/74 (44%) samples known to harbour one or more mutations by SS, UDS revealed that up to four ‘minor’ mutations with 1–20% abundance were present in addition to the ‘dominant’ one(s). The type of mutations could easily be accounted for by TKI exposure history, since the majority were known to be poorly sensitive either to the current or to the previous TKI received. The higher degree of complexity was evident also when the clonal relationships of multiple mutations were reconstructed (Table 1). This revealed that identical mutations may be acquired in parallel by independent populations (e.g., one wild-type and one already harboring a mutation), via the same or different nucleotide changes leading to the same amino acid substitution (convergent evolution). In addition, longitudinal quantitative follow-up of mutated populations revealed that: Conclusions: Disclosures: Soverini: ARIAD: Consultancy; Bristol-Myers Squibb: Consultancy; Novartis: Consultancy. Castagnetti:Novartis: Honoraria; Bristol Myers Squibb: Honoraria. Luppi:CELGENE CORPORATION: Research Funding. Rosti:Bristol Myers Squibb: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Research Funding. Baccarani:ARIAD, Novartis, Bristol Myers-Squibb, and Pfizer: Consultancy, Honoraria, Speakers Bureau. Martinelli:NOVARTIS: Consultancy, Honoraria, Speakers Bureau; BMS: Consultancy, Honoraria, Speakers Bureau; PFIZER: Consultancy; ARIAD: Consultancy.

scholarly journals Characteristics and outcomes of patients with V299L BCR-ABL kinase domain mutation after therapy with tyrosine kinase inhibitors

Blood ◽  
2012 ◽  
Vol 120 (16) ◽  
pp. 3382-3383 ◽  
Author(s):  
Elias Jabbour ◽  
Van Morris ◽  
Hagop Kantarjian ◽  
Cameron C. Yin ◽  
Elizabeth Burton ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Tyrosine Kinase Inhibitors ◽  
Kinase Inhibitors ◽  
Kinase Domain ◽  
Abl Kinase ◽  
Kinase Domain Mutation

Generation of Specific Resistance Profiles in FLT3-ITD and FIP1L1-PDGFRalpha towards Specifically Acting Tyrosine Kinase Inhibitors.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1376-1376
Author(s):  
Nikolas von Bubnoff ◽  
Silvia Thoene ◽  
Sivahari P. Gorantla ◽  
Jana Saenger ◽  
Christian Peschel ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Tyrosine Kinase Inhibitors ◽  
Kinase Inhibitors ◽  
Kinase Inhibitor ◽  
Point Mutations ◽  
Kinase Domain ◽  
Myelogenous Leukemia ◽  
Resistance Mutations ◽  
Abl Kinase ◽  
Mechanism Of Resistance

Abstract BCR-ABL kinase domain mutations constitute the major mechanism of resistance in patients with chronic myelogenous leukemia treated with the ABL kinase inhibitor imatinib. Mutations causing resistance to therapeutic kinase inhibition were also identified in other target kinases in various malignant diseases, such as FLT3-ITD in acute myelogenous leukemia, cKit in gastrointestinal stromal tumors, EGFR in patients with lung cancer, and FIP1L1-PDGFRalpha in hypereosinophilic syndrome. Thus, mutations in kinase domains seem to be a general mechanism of resistance to therapeutically applicated tyrosine kinase inhibitors. We recently developed a cell-based screening strategy that allows one to predict the pattern and relative abundance of BCR-ABL resistance mutations emerging in the presence of imatinib, and the novel ABL kinase inhibitor AMN107 (nilotinib). We therefore intended to determine, if this method would also allow the generation of resistant cell clones with other oncogeneic tyrosine kinases as targets in the presence of specifically acting kinase inhibitors. When FLT3-ITD and su5614 were used as drug/target combination in our cell-based method, the frequency of resistant clones in the presence of su5614 at 10 times the IC50 was 0.17 per million cells. In 40 per cent of resistant clones, point mutations were detected leading to amino acid exchanges within the FLT3-ITD split kinase domain. The yield of resistant clones was increased by the factor of 14 to 2.37 per million cells by adding ethyl-nitrosourea (ENU), a potent inducer of point mutations. Also, the proportion of mutant clones increased from 40 to 74 per cent. In 83 mutant clones that were examined so far, we detected eight exchanges affecting kinase domain two (TK2) of the split kinase domain within or shortly behind the FLT3-ITD activation loop (A-loop). We did not detect exchanges affecting TK1. We next examined whether resistant clones would also come up with FIP1L1-PDGFRalpha-transformed cells in the presence of imatinib. Again, the yield of resistant clones increased when cells were pretreated with ENU, and a proportion of resistant clones contained mutations in the FIP1L1-PDGFRalpha kinase domain, affecting the nucleotide-binding loop (P-loop) and A-loop. We conclude that cell-based resistance screening is a simple and powerful tool that allows prediction of resistance mutations towards kinase inhibitors in various relevant oncogeneic kinases.

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