Clinical Characteristics and Outcome of Patients (pts) with T315I Mutation after Imatinib Failure.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 2189-2189
Author(s):  
Elias Jabbour ◽  
Hagop Kantarjian ◽  
Dan Jones ◽  
Francis Giles ◽  
Gautam Borthakur ◽  
...  
Keyword(s):  
Overall Survival ◽  
Tyrosine Kinase ◽  
Tyrosine Kinase Inhibitors ◽  
Clinical Characteristics ◽  
Kinase Inhibitors ◽  
Cytogenetic Response ◽  
Kinase Domain ◽  
Abl Kinase ◽  
Hematologic Response ◽  
T315i Mutation

Point mutations of the Bcr-Abl kinase domain are the most frequently identified mechanism of resistance in patients (pts) with CML who failed imatinib. T315I is an imatinib pocket binding mutation within the Bcr-Abl kinase domain that is highly resistant to imatinib as well as to the novel tyrosine kinase inhibitors (NTKIs) (eg, dasatinib, nilotinib) both in vitro and in vivo. It has thus been suggested that these pts have a very poor prognosis. To define the clinical characteristics and outcome of these pts, we reviewed all pts with this mutations identified at our institution after failure to imatinib. T315I was detected in 15 of 112 patients (13%) harboring kinase domain mutations. Median age was 49 years (range, 34-66 years). At the time imatinib was started, 12 pts were in chronic (CP) and 3 in accelerated (AP). Ten pts had received prior interferon therapy. The best response to imatinib was major molecular response in 1, major cytogenetic response in 5 (complete in 2), and complete hematologic response in 8. One patient was intolerant to imatinib. The median duration of response was 37 months (range, 10–60 months). T315I was identified after a median of 48 months (range, 10–83 months). At the time the mutation was identified, 9 patients had transformed (7 to AP, 2 to BP). Clonal evolution was observed in only 1 pt. Fourteen patients received subsequent NTKIs; 3 of them received both nilotinib and dasatinib. Among them, 1 patient achieved a partial hematologic response with nilotinib that lasted for 3 months and 1 other had T315I identified while in complete cytogenetic response induced by nilotinib that has been sustained for 16+ months. After a median follow-up of 27 months (range, 3–42 months), 11 pts (73%) are alive: 8 are alive with active disease, and 3 patients are alive with ongoing response: 1 in complete molecular remission following allogeneic stem cell transplantation, 1 in partial cytogenetic response following treatment with aurora kinase inhibtor MK0457, and one in sustained complete cytogenetic response with ongoing treatment with nilotinib. Four patients have died of disease progression. Except for previous treatment with interferon (more frequent in patients harboring the T315I mutation; p=0.024) and the lack of response to the NTKI (p=0.001), there was no difference in patients characteristics and previous response to imatinib compared to patients with other mutations. Similarly, there was no difference in overall survival among patients with T315I mutations or other mutations (p=0.71). In conclusion T315I is a highly resistant mutation to conventional tyrosine kinase inhibitors; however occasional responses can be observed and overall survival may not be as poor as previously reported.

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.

Combination Therapy with Tyrosine Kinase Inhibitors and Agents with Different Mechnisms of Actions Is Effective in a Patient with Chronic Myeloid Leukemia Harboring the T315l BCR - ABL1 Mutation.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 4282-4282
Author(s):  
Fabio P S Santos ◽  
Jorge Cortes ◽  
Charles Koller ◽  
Elias Jabbour
Keyword(s):  
Chronic Myeloid Leukemia ◽  
Combination Therapy ◽  
Tyrosine Kinase ◽  
Tyrosine Kinase Inhibitors ◽  
Myeloid Leukemia ◽  
Kinase Inhibitors ◽  
Specific Inhibitor ◽  
Cytogenetic Response ◽  
Molecular Response ◽  
T315i Mutation

Abstract Abstract 4282 Mutations of BCR-ABL1 have been observed in 50% of patients with chronic myeloid leukemia (CML) who develop resistance to imatinib. The gate-keeper mutation T315I is one of the mutations with universal resistance to imatinib and to the second-generation tyrosine kinase inhibitors (TKI) that are approved for the treatment of patients with imatinib failure. The use of new kinase inhibitors with in vitro activity against T315I mutation as well as other agents with different mechanisms of actions is being evaluated in clinical trials. We report the case of a 57-year old man that was diagnosed with CML in 2003. Patient received initial therapy with standard-dose imatinib that was subsequently increased to 800 mg daily. He did achieve a complete cytogenetic response (CCyR) 9 months post dose escalation. He was followed by RT-PCR for BCR-ABL1.. In May, 2007, the patient BCR-ABL1/ABL1 ratio increased to 16.38 but the patient remained in CCyR. BCR-ABL1 sequencing revealed the T315I mutation in 100% of cells (Figure 1). One month later the patient lost CCyR (5% Philadelphia-positive [Ph+] cells) and the BCR-ABL1/ABL1 ratio was 5.08. The patient was started on the T315I specific inhibitor KW-2449 (100 mg orally twice daily for 14 days, every 3 weeks). Patient had a progressive decline in percentage of cells with the T315I mutation (Figure 1). However, at the same time he had an increase in percentage of Ph+ cells. In September, 2007, three months after starting therapy with KW-2449, patient had no cytogenetic response (80% Ph+ cells, PCR for BCR-ABL1 ratio > 100) and the T315I mutation was undetectable. At that time, a new ABL1 sequencing revealed the F359I mutation (no quantification was done). Patient was maintained on KW-2449 for the next 6 months, without significant improvement in cytogenetic response nor BCR-ABL1 ratio, but the clone with the T315I mutation did not reappear. In February, 2008, the patient lost hematologic response and presented with an elevated white blood cell count of 22×109/L. The F359I mutation was still present. Therapy with KW-2449 was stopped and the patient started dasatinib 100 mg/day and Interferon-a 3,000,000 units. Three months later, the patient acheived CCyR with a BCR-ABL1/ABL1 ratio of 0.05. At the last evaluation, 16 months after the start of dasatinib and interferon combination, the patient was maintaining CCyR and major molecular response. In conclusion, this case illustrates the benefit of the use of combination therapy, mainly TKI and agent with different mechanism of action either sequentially (TKI followed by KW-2449) or concomitantly (TKI + interferon) in eradicating resistant disease with T315I clone. Figure 1 Serial Monitoring of Ph+ Cells, T315I Cells and BCR-ABL1/ABL1 Ratio Figure 1. Serial Monitoring of Ph+ Cells, T315I Cells and BCR-ABL1/ABL1 Ratio Disclosures: Cortes: Novartis: Research Funding. Jabbour:Novartis: Speakers Bureau; Bristol Myers Squibb : Speakers Bureau.

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.

Mutation Mediated Resistance to the Tyrosine Kinase Inhibitors Imatinib, Dasatinib & Nilotinib in Philadelphia Positive Leukaemia

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 4245-4245 ◽  
Author(s):  
Lisa M O’ Connor ◽  
Stephen Langabeer ◽  
Shaun R. McCann ◽  
Eibhlin Conneally
Keyword(s):  
Tyrosine Kinase ◽  
Tyrosine Kinase Inhibitors ◽  
Molecular Mechanisms ◽  
Second Generation ◽  
Kinase Inhibitors ◽  
Kinase Inhibitor ◽  
Kinase Domain ◽  
Patient Specific ◽  
Abl Kinase ◽  
Clinically Significant

Abstract The Philadelphia chromosome is formed as a result of a reciprocal translocation between chromosomes 9 and 22 and results in the formation of the hybrid oncoprotein BCR-ABL. It is observed in over 95% of Chronic Myeloid Leukaemia (CML) and approximately 30% of adult Acute Lymphoblastic Leukaemia (ALL) cases. Imatinib Mesylate (IM), a tyrosine kinase inhibitor that specifically binds BCR-ABL in its inactive conformation has revolutionized therapy for CML and Ph+ ALL. However, resistance develops in a significant proportion of patients and is predominantly mediated by single base-pair substitutions within the BCR-ABL kinase domain leading to changes in the amino acid composition that inhibit IM binding whilst retaining BCR-ABL phosphorylation capacity. Second generation tyrosine kinase inhibitors such as Dasatinib and Nilotinib retain activity in IM-resistant patients due to less stringent binding requirements and represent viable alternatives for IM-resistant patients with a suitable molecular profile. In this study, we undertook to examine the molecular mechanisms underlying IM resistance. A cohort of 40 patients with either primary or acquired resistance or intolerance to IM was identified by persistent high or increasing levels of BCR-ABL transcripts determined by real-time quantitative PCR. An allele-specific PCR screen was used to sensitively detect the clinically significant T315I mutation, which renders patients insensitive to currently available tyrosine kinase inhibitors: five (12.5%) IM resistant/intolerant patients were T315I positive. To further elucidate the molecular mechanisms of mutation induced resistance, the BCR-ABL kinase domain was screened for the presence of a mutation using a sensitive denaturing high performance liquid chromatography (dHPLC) approach. Samples showing evidence of mutation were examined by direct sequencing to identify the mutation(s) present. Kinase domain mutations have been identified in 20 of the 40 (50%) patients examined to date and these include p-loop mutations (M244V, G250E, Q252H), IM-binding domain mutations (T315I), catalytic domain mutations (M351T), an activation-loop mutation (L387M). Three previously unreported mutations were identified in patients with indications of IM resistance (T267A, E275Q) and Nilotinib resistance (L273M). The L273 residue lies adjacent to a region of the BCR-ABL kinase domain bound by Nilotinib. Three patients were found to harbour mutations at two distinct kinase domain residues while one patient harboured mutations at three distinct residues, supporting the theory that patients who develop mutation-mediated resistance to one kinase inhibitor may become resistant to subsequent inhibitors by a similar mechanism. The identification of clinically significant mutations facilitates selection of alternative approaches to therapy such as dose escalation of IM, second generation tyrosine kinase inhibitors or allogeneic stem cell transplant, if eligible, at an early stage in a patient’s disease, tailoring patient specific approaches to therapy.

Dynamics of BCR-ABL kinase domain mutations in chronic myeloid leukemia after sequential treatment with multiple tyrosine kinase inhibitors

Blood ◽  
2007 ◽  
Vol 110 (12) ◽  
pp. 4005-4011 ◽  
Author(s):  
Jorge Cortes ◽  
Elias Jabbour ◽  
Hagop Kantarjian ◽  
C. Cameron Yin ◽  
Jianqin Shan ◽  
...  
Keyword(s):  
Chronic Myeloid Leukemia ◽  
Tyrosine Kinase ◽  
Tyrosine Kinase Inhibitors ◽  
Myeloid Leukemia ◽  
Kinase Inhibitors ◽  
Kinase Domain ◽  
Differential Sensitivity ◽  
Mutation Site ◽  
Abl Kinase

AbstractDasatinib and nilotinib are potent tyrosine kinase inhibitors (TKIs) with activity against many imatinib-resistant chronic myeloid leukemia (CML) clones with BCR-ABL kinase domain (KD) mutations, except T315I. We assessed for changes in the BCR-ABL KD mutation status in 112 patients with persistent CML who received a second-generation TKI after imatinib failure. Sixty-seven different KD mutations were detected before the start of therapy with a second TKI, with T315I seen in 15%. Equal numbers of patients received nilotinib or dasatinib following imatinib, and 18 received 3 TKIs. Response rates were similar for patients with and without mutations, regardless of mutation site except for T315I. Overall, 29 patients (26%) developed new KD mutations after therapy with a second (n = 24) or third (n = 5) TKI, but only 4 (4%) developed T315I. In 73% of cases, the KD mutations that persisted or developed following switch to new TKI were at sites also found in prior in vitro TKI mutagenesis assays. Although there is only a mild increase in mutation frequency with sequential TKI treatment, novel mutations do occur and mutation regression/acquisition/persistence generally reflects the in vitro differential sensitivity predicted for each TKI. In this study, there was no marked increase in development of T315I.

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).

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