T790M突变和cMet扩增

First in human phase I study of MK-2461, a small molecule inhibitor of c-Met, for patients with advanced solid tumors
http://meeting.ascopubs.org/cgi/ ... t/26/15_suppl/14657
Background: MK-2461 is a potent small molecule inhibitor of c-Met, a receptor tyrosine kinase involved in tumor cell proliferation and motility. Over-expression of c-Met or Met gene amplification has been associated with poorer prognosis in several tumor types. Methods: Multicenter, open-label, phase I dose escalation study in patients with advanced solid tumors refractory to standard therapy. Drug was administered by mouth daily or twice daily (BID) for 28 days followed by a 14 day rest period during cycle 1. Patients received continuous dosing subsequently for 28-day cycles. Maximum tolerated dose (MTD) was determined using a standard 3+3 dosing design. PK analyses were performed on days 1 and 28 of cycle 1. Results: Fourteen patients (10 M/ 4 F), mean age 54 (range 19–76), have received 31 cycles (range 1–6). Dose levels tested include 60mg daily, 60mg BID, 120mg BID, and 180 mg BID. Toxicity data are available for 11 patients treated at the 60mg daily-120mg BID dosing cohorts. Ten patients (91%) have not experienced > Grade 1 drug-related toxicity. Dose limiting toxicity has not been reached and no objective antitumor responses have been observed. One patient with mucinous carcinoma of the appendix had stable disease for 6 cycles. Common drug related toxicities are outlined in the table below. Four patients experienced serious adverse experiences that were considered not related to MK-2461. PK analysis revealed a rapid Tmax (1–3 hr) across all dosing cohorts with a terminal half life of 6.3 hr following the final day of dosing for the QD dosing cohort. Conclusions: Twice daily administration of MK-2461 at the doses tested is well tolerated. Terminal t1/2 suggests acceptable drug plasma concentrations expected at BID dosing. Dose escalation continues.

MK2461 Phase I/II Study in Patients With Advanced Solid Tumors (MK-2461-002 AM1)(COMPLETED)
http://www.clinicaltrial.gov/ct2 ... =MK-2461&rank=1

老马 能不能把易瑞沙、特罗凯耐药对策那个图翻译成中文的方便大多数可以学习下！

http://www.Dana-Farber.org/T790Mstudy
Pasi A. Janne

T790M: Understanding Its Role in Resistance and Potential as a Therapeutic Target
http://www.informedicalcme.com/egfr/T790M/
Interestingly, T790M-mediated resistance may not be the primary mechanism in patients with EGFR mutant tumors who develop brain metastasis while on treatment. In at least two autopsy cases of patients with acquired resistance, T790M mutations were found in peripheral tumors but not in brain metastases.35,69 Early data suggest that this phenomenon may occur due to poor penetration of the drug into the central nervous system, leading to a lack of selection pressure for cells harboring the T790M mutation. Thus, EGFR tyrosine kinase inhibitors that can better penetrate the blood-brain barrier could be clinically useful in patients with brain metastases.

The Role of MET Amplification in EGFR Resistance
http://www.informedicalcme.com/egfr/met-amplification/


Modeling Genotype-Associated Sensitivity to Receptor Tyrosine Kinase Inhibitors in
Lung Cancer-Derived Cell Lines
http://www.informedicalcme.com/e ... bitors-sensitivity/
We have recently begun to use such cell lines to model another aspect of drug treatment. Specifically, we have addressed the question of whether first-line EGFR-TKI therapy is likely to provide greater clinical benefit than second- line treatment. Currently, erlotinib is only approved for clinical use in chemotherapy-refractory NSCLC. However, recent clinical studies in which EGFR-mutant NSCLCs are treated with first-line EGFR-TKIs have revealed impressively high response rates.33 A standard component of chemotherapy for NSCLC is platinum, which can activate at least one signaling pathway (PI3K kinase/AKT) whose activation has been associated with acquired resistance to EGFR-TKIs. Therefore, we tested the possibility that exposure of EGFR-mutant erlotinib-sensitive NSCLC cells to platinum in vitro would lead to a subsequent reduction in erlotinib sensitivity.91 This was indeed found to be the case. Although the IC50 values for erlotinib in a cell viability assay comparing cisplatin-exposed cells and cisplatin-naive cells were similar, cisplatin-pretreated cells demonstrated a substantially increased ability to yield TKI-resistant clones in a longer-term clonogenic colony-forming assay. Moreover, this effect seemed to reflect the ability of cisplatin to activate the PI3K kinase/AKT cell survival pathway. These findings suggest that while initial response rates may be similar for EGFR-mutant NSCLCs in the first- or second-line setting, first-line treatment might lead to a longer period of progression-free survival. Considering the numerous clinical studies underway in which first-line EGFR-TKI therapy is being examined, data that address this possibility should be forthcoming.

Novel D761Y and common secondary T790M mutations in epidermal growth factor receptor-mutant lung adenocarcinomas with acquired resistance to kinase inhibitors
http://www.ncbi.nlm.nih.gov/pubmed/17085664
Abstract
PURPOSE: In patients whose lung adenocarcinomas harbor epidermal growth factor receptor (EGFR) tyrosine kinase domain mutations, acquired resistance to the tyrosine kinase inhibitors (TKI) gefitinib (Iressa) and erlotinib (Tarceva) has been associated with a second-site EGFR mutation, which leads to substitution of methionine for threonine at position 790 (T790M). We aimed to elucidate the frequency and nature of secondary EGFR mutations in patients with acquired resistance to TKI monotherapy.

EXPERIMENTAL DESIGN: Tumor cells from patients with acquired resistance were examined for secondary EGFR kinase domain mutations by molecular analyses.

RESULTS: Eight of 16 patients (50% observed rate; 95% confidence interval, 25-75%) had tumor cells with second-site EGFR mutations. Seven mutations were T790M and one was a novel D761Y mutation found in a brain metastasis. When combined with a drug-sensitive L858R mutation, the D761Y mutation modestly reduced the sensitivity of mutant EGFR to TKIs in both surrogate kinase and cell viability assays. In an autopsy case, the T790M mutation was found in multiple visceral metastases but not in a brain lesion.

CONCLUSIONS: The T790M mutation is common in patients with acquired resistance. The limited spectrum of TKI-resistant mutations in EGFR, which binds to erlotinib in the active conformation, contrasts with a wider range of second-site mutations seen with acquired resistance to imatinib, which binds to ABL and KIT, respectively, in closed conformations. Collectively, our data suggest that the type and nature of kinase inhibitor resistance mutations may be influenced by both anatomic site and mode of binding to the kinase target.

Acquired Resistance to Epidermal Growth Factor Receptor Kinase Inhibitors Associated with a Novel T854A Mutation in a Patient with EGFR-Mutant Lung Adenocarcinoma
http://clincancerres.aacrjournals.org/content/14/22/7519.full


D761Y Mutation.PDF (88.59 KB, 下载次数: 217)

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The Epidermal Growth Factor Receptor D761Y Mutation and Effect of Tyrosine Kinase Inhibitor
http://clincancerres.aacrjournal ... 431.1.full.pdf+html

MET Amplification Leads to Gefitinib Resistance in Lung Cancer by Activating ERBB3 Signaling
在肺癌中，MET扩增通过激活ERBB3信号通路导致对吉非替尼的耐药

Jeffrey A. Engelman, et al.

The epidermal growth factor receptor (EGFR) kinase inhibitors gefitinib and erlotinib are effective treatments for lung cancers with EGFR activating mutations, but these tumors invariably develop drug resistance. Here, we describe a gefitinib-sensitive lung cancer cell line that developed resistance to gefitinib as a result of focal amplification of the MET proto-oncogene. inhibition of MET signaling in these cells restored their sensitivity to gefitinib. MET amplification was detected in 4 of 18 (22%) lung cancer specimens that had developed resistance to gefitinib or erlotinib. We find that amplification of MET causes gefitinib resistance by driving ERBB3 (HER3)–dependent activation of PI3K, a pathway thought to be specific to EGFR/ERBB family receptors. Thus, we propose that MET amplification may promote drug resistance in other ERBB-driven cancers as well.

Engelman_Science2007.pdf (690.34 KB, 下载次数: 232)

2013-12-9 13:05 上传

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MET amplification occurs with or without T790M mutations in EGFR mutant lung tumors with acquired resistance to gefitinib or erlotinib
发生在对吉非替尼或厄洛替尼耐药的EGFR突变的肺癌中伴有或不伴有T790M突变的MET扩增

James Bean at al.

In human lung adenocarcinomas harboring EGFR mutations, a second-site point mutation that substitutes methionine for threonine at position 790 (T790M) is associated with approximately half of cases of acquired resistance to the EGFR kinase inhibitors, gefitinib and erlotinib. To identify other potential mechanisms that contribute to disease progression, we used array-based comparative genomic hybridization (aCGH) to compare genomic profiles of EGFR mutant tumors from untreated patients with those from patients with acquired resistance. Among three loci demonstrating recurrent copy number alterations (CNAs) specific to the acquired resistance set, one contained the MET proto-oncogene. Collectively, analysis of tumor samples from multiple independent patient cohorts revealed that MET was amplified in tumors from 9 of 43 (21%) patients with acquired resistance but in only two tumors from 62 untreated patients (3%) (P
0.007, Fisher’s Exact test). Among 10 resistant tumors from the nine patients with MET amplification, 4 also harbored the EGFRT790M mutation. We also found that an existing EGFR mutant lung adenocarcinoma cell line, NCI-H820, harbors MET amplification in addition to a drug-sensitive EGFR mutation and the T790M change. Growth inhibition studies demonstrate that these cells are resistant to both erlotinib and an irreversible EGFR inhibitor (CL-387,785) but sensitive to a multikinase inhibitor (XL880) with potent activity against MET. Taken together, these data suggest that MET amplification occurs independently of EGFRT790M mutations and that MET may be a clinically relevant therapeutic target for some patients with acquired resistance to gefitinib or erlotinib.

zpq20932.pdf (593.37 KB, 下载次数: 198)

2013-12-9 13:11 上传

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发生在对吉非替尼或厄洛替尼耐药的EGFR突变的肺癌中伴有或不伴有T790M突变的MET扩增

这是不是说易特耐药可能同时存在T790和MET,也可能单独存在.

Combined EGFR/MET or EGFR/HSP90 inhibition is effective in the treatment of lung cancers co-driven by mutant EGFR containing T790M and MET
0008-5472.CAN-11-3720.full.part1.rar (1.44 MB, 下载次数: 199)

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0008-5472.CAN-11-3720.full.part2.rar (917.2 KB, 下载次数: 223)

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三楼论文的大概内容

Combined EGFR/MET or EGFR/HSP90 inhibition is effective in the treatment of lung cancers co-driven by mutant EGFR containing T790M and MET
联合EGFR抑制剂和MET抑制剂或者EGFR抑制剂和HSP90抑制剂能有效的作用于带有EGFR突变合并T790M和MET扩增的肺癌细胞

T790M出现在大约50%对EGFR产生耐药的肺癌患者中，另外还有5-15%的患者因为MET的扩增而出现耐药，同时出现T790M和MET扩增的患者大概占有5-33%的比例，这篇论文就是想确定对于联合针对T790M的WZ4002和针对MET的crizotinib或者17-DMG，是否能够有效作用于同时含有T790M和MET扩增的肺癌细胞。

实验过程：
研究人员采用的方法是产生三种转基因鼠，一种还有MET扩增的基因(CCSP-rtTA/Tet-op-hMET)，另两种分别含有外显子19deletion合并T790M的基因(CCSP-rtTA/EGFR exon 19 deletion/T790M, TD)和L858R合并T790M的基因(CCSP-rtTA/EGFR L858R/T790M, TL)，然后让MET扩增的小鼠和后面两种基因小鼠杂交，就得到了两种同时含有T790M和MET扩增的基因鼠(使用TD/MET和TL/MET来表示)。

首先，研究人员采用多西环素诱导出TD/MET和TL/MET小鼠产生可测量的肺癌组织，作为对比，也诱导了TD和TL小鼠产生不包含MET扩增的肺癌。

接着，研究人员使用WZ4002(50mg/kg, qd)来治疗这四组小鼠。两周后的定量MRI显示，TD和TL组的肿瘤有了大幅度的缩小(-79.6%和-71.2%)，但TD/MET和TL/MET缩小得就不是特别显著了(-23.2%和-17.9%)，即使再加上针对EGF的西妥昔单抗后，缩小幅度也没有得到提高，提示可能产生了对WZ4002单药的耐药机制。

然后，研究人员又对这四组小鼠使用了MET抑制剂crizotinib(20mg/kg, qd)，结果所有小鼠都没能出现可测量的肿瘤的缩小，即使将剂量提升至50mg/kg也无效，分析显示MET的磷酸化已被大幅度抑制，提示此时肿瘤细胞生长主要依赖于EGFR通路。

最后，研究人员联合了WZ4002(50mg/kg)和crizotinib(20mg/kg)，所有小鼠都出现了显著的影像学相应，其中之前对WZ4002反应较为微弱的TD/MET组和TL/MET组，其肿瘤缩小比例分别为-69.5%和-74.0%。因为EGFR和MET的调节都需要HSP90的参与，联合WZ4002(50mg/kg)和HSP90抑制剂17-DMG(20mg/kg)对TD/MET和TL/MET组产生了显著的治疗效果(TD和TL组效果未见较WZ4002有更多的提升，提示WZ4002单药已经达到了最大的作用)。之后一系列的组织病理分析、免疫组化和蛋白质印迹分析都与影像学结果一致。

讨论：
T790M和MET扩增是EGFR抑制剂耐药的最主要的两个原因，NCI-H820肺癌细胞系(该细胞系同时含有外显子19deletion/T790M/MET扩增)提示T790M和MET扩增可以发生在同一个肿瘤细胞内部。对NCI-H820细胞系的体外实验表明，该细胞系的生长和侵袭主要依赖于MET扩增而不是EGFR+T790M，但该实验未能重复这一结论，对TD/MET和TL/MET小鼠，单独使用T790M和MET抑制剂，都无法取得显著的治疗效果。该实验主要是发现了带有MET扩增的对EGFR TKI耐药的细胞系对EGFR和MET的联合抑制较为敏感。但该实验也具有一些缺陷，首先是小鼠模型上的MET的表达可能与人类患者肺癌细胞中的表达并不一致。其次，并未考虑到HGF(MET配体)过表达的影响。
对于HSP90抑制剂来说，17-DMG对TD和TL的效果都较短(在应用17-DMG三周之后，肿瘤就会重新开始生长)，但联合WZ4002就能产生较为显著的效果，提示HSP90抑制剂对WZ4002具有协调作用。
之前的研究显示，MET不仅能通过联合ERBB3激活由Akt介导的下游通路，同时也能通过Gab1激活PI3K通路。于此一致，WZ4002并未在TD/MET组中产生较为显著的Akt磷酸化抑制效果，提示即使再EGFR受到抑制时，MET也能激活Akt活性。实验中采用WZ4002联合crizotinib或者17-DMG的方法，在所有模型中都有效地抑制了PI3K和MAPK信号通路