T790M突变和cMet扩增

四楼的评述总结

Don't kick the TKI - kick在英文里是踢的意思，Don't kick the TKI可以直译为别踢走TKI，在这篇评述里，作者的意思是在应用TKI治疗的患者出现疾病进展的时候，不要轻易地停止使用TKI。

作者谈到应该将具有EGFR或ALK突变的患者与没有这些突变的患者区别开来。具有突变的患者可以看做是患有不同的疾病。在这部分患者的肿瘤中，由于肿瘤异质性，少部分的肿瘤细胞是野生型的，大部分是突变型的。甚至在应用TKI治疗出现进展的时候，大部分的细胞还是敏感突变型的，只有少部分细胞出现了耐药突变。

从实验室和临床观察结果来看，出现了第二突变(T790M)的细胞，生长速度慢于具有敏感突变的细胞。这点可以参照这个帖子作为论证。所以反过来说，敏感突变的细胞比耐药突变的细胞生长速度快。因此一旦停止使用TKI，很有可能会出现肿瘤的快速生长，即所谓的“爆发性增长(flare phenomenon)”，可以参见这个帖子。

在具有以上的知识之后，很明显就要仔细地观察患者的进展状况。在化疗经验中，当进展至出现症状，或者出现了新的病灶甚至有了其他部位的转移时，就该换治疗方案了。作者认为扩展至TKI的治疗中，就是需要增加一些其他治疗，而不停止使用TKI。

作者说到了RECIST标准，这个实体瘤评价标准认为在可测量病灶的最小直径出现20%以上的增长时，即可判断为进展。打个比方，原来8cm的病灶缩小至2cm，之后又增长至2.4cm，按照RECIST的说法，这个就是进展了。

在临床中，有时会遇见有些患者具有单独的病灶并且已经缓慢地生长很多年了。停止使用TKI对这些患者来说反而是种伤害。临床医生需要做的就是确定患者没有症状并且能够很好的耐受药物，要是这两个条件都满足，作者建议就是继续使用TKI，同时密切的进行观察。

对于那些必须要改变治疗方案的患者，作者认为最好是继续使用TKI，或者切换到另外一种相同靶点的TKI上。对于出现的新症状和新病灶来说，TKI加上局部治疗是可行的。

最后作者总结到，临床医生需要仔细的甄别所谓的进展，才能对不同的患者做出最佳的选择。

易、特耐药后虽然T90M突变的几率占了50%，但是好像目前4002的有效时间都不太长啊，这个问题有点头疼。

是不是可以理解为联合EGFR靶点和T790M、MET靶点用药可能比单独用抑制T790M、MET靶点的药更有效。

MET inhibition in lung cancer
MET抑制剂在肺癌中的应用

注：这篇综述太长了，选取了一部分有价值的翻译给大家看看

Met discovery and mechanism of action
Met的发现和作用机制

Met is a heterodimer receptor tyrosine kinase composed of a α-chain and a β-chain, linked by a disulphide bond.
Met是一种二聚的受体酪氨酸激酶，由一个α链和一个β链通过二硫键链接而成


从这张图可以看到α链和β链，磷酸根的转移发生于Tyr 1234和Tyr 1235，而Tyr 1349和Tyr 1356能插入到多底物的停泊位点，从而通过募集SH2链接分子启动下游信号转导

Met was originally isolated as the product of a human oncogene, trp-met, in tumor cells treated with a chemical carcinogen. Met gene encodes a 170-kD protein (p170met) that has constitutive and ligand-independent tyrosin kinase activity. Met has pivotal functions in embryogenesis and organogenesis of placenta, liver, kidney, neurons and muscles (22-25).
Met最开始作为人类原癌基因trp-met的产物，在由化学致癌物诱导的癌细胞中被分离出来。Met基因编码一个170kD的蛋白质，该蛋白质具有结构化并且独立于配体的磷酸化激酶活性。Met在胚胎形成和如胎盘、肝脏、肾脏、神经和肌肉等器官生成等功能上具有关键性作用。

Moreover, in vivo, Met receptor activation determines a phenomenon called “invasive growth”, which includes cell proliferation, scattering, survival, motility and invasion, epithelial-mesenchymal transition and branched morphogenesis (26,27).
而且，Met受体激活在体内表现出一种称为“侵袭性生长”的现象，主要包括细胞的增值、散播、生存、移动和侵袭、上皮间质转化(EMT)和分支形态生成。

The natural ligand for this receptor is the HGF, produced by stromal and mesenchymal cells, that acts primarily on Met-expressing epithelial cells in an endocrine and/or paracrine fashion (24,28). HGF-induced Met tyrosine kinase activation is regulated by paracrine ligand delivery, ligand activation at the target cell surface and ligand-activated receptor internalization and degradation (29). Going more into details, when HGF binds to the Met receptor, Met major autophosphorylation sites (located within the tyrosine kinase domain) are phosphorylated, with subsequent intrinsic catalytic activation of multiple signaling cascades involved in cell proliferation, survival, angiogenesis, morphogenesis, cell scattering, motility, migration and invasion. An activated docking site in the kinase domain further recruits intracellular adaptor molecules through the SH2 domains and other recognition motifs, such as GAB1 (a key coordinator of the cellular responses to Met). Downstream signaling of the GRB2-mitogen-activated protein kinase (MAPK) cascade, PI3K-mTOR pathway, and STAT pathway are eventually activated, mediating various cellular functions (27,30,31). Finally, in order to activate the receptor, proteolytic cleavage of proHGF is necessary (25).
该受体的自然配体是肝细胞生长因子(HGF)，由基质和间质细胞产生，主要以内分泌和旁分泌的方式作用于表达Met的上皮细胞。HGF诱导的Met酪氨酸激酶的激活通过三种方式进行调节：旁分泌配体输送、在靶细胞表面的配体激活和配体激活后受体的内在化和降解。更详细的描述是，当HGF绑定到Met受体之后，Met主要自磷酸化位点(位于其酪氨酸激酶域中)磷酸化，导致一系列涉及细胞增值、生存、血管生成、形态发生、细胞散播、移动、迁移和侵袭的下游级联通路的催化激活。在激酶域的一个激活的停泊位点将会通过SH2域募集胞内的链接分子和其他识别基序如GAB1(作为细胞对Met响应的一个关键的调节器)。最终，下游信号如GRB2-MAPK级联、PI3K-mTor通路和STAT通路将被激活，介导多种细胞功能。最后，要激活受体，proHGF还需要经过蛋白酶水解切割。


Met和其下游信号通路的一个总体描述图

HGF is mainly produced by stromal tissue like liver and bone marrow, and is expressed in a multitude of mesenchymal-derived cells. Being Met expression detected in the epithelium of most tissues, this indicates that HGF-Met signal transduction pathway contributes to mesenchymal-epithelial interactions (24,32-34).
HGF主要由基质组织产生如肝脏和骨髓，能够在大量的间质来源的细胞中表达。因为在绝大多数组织的上皮细胞中检测到了Met的表达，这表面HGF-Met信号转导促使了上皮间质转化过程。

Met downregulation occurs through rapid internalization of Met itself and subsequent degradation by the lysosome: this process is regulated by ligand-dependent ubiquitination of Met, a process also modulated by specific tyrosine phosphatases and recently identified as proteins decorin and LRIG1 (35,36).
Met的下调发生于Met自身的快速内在化以及随后被溶酶体降解：配体依赖的Met泛素化调节该过程，而泛素化又受到特定的酪氨酸磷酸化酶的控制，最近研究识别出该酶为胶饰蛋白多糖和LRIG1。

Met can be altered through receptor overexpression, genomic amplification, mutations or alternative splicing. These alterations lead to signaling deregulation that can be mediated through ligand (HGF)-independent receptor activation or through its ligand (HGF)-dependent activation via autocrine (intratumoral HGF), paracrine (mesenchymal or microenvironmental HGF), or endocrine (circulatory HGF) loop signaling cascades (29).
Met可以通过受体的过表达、基因组的扩增、突变和选择性剪切被改变。这些变化导致了信号的失调，该失调是受两种作用的介导：不依赖于配体的受体激活或者依赖于配体的受体激活，配体依赖的激活主要通过自分泌(瘤内的HGF)、旁分泌(间质或者微环境中的HGF)和内分泌(血液循环中的HGF)方式循环进行的信号级联反应。

HGF and Met are highly expressed in various stem and progenitors cells, but are only expressed as low levels in their mature cells (25). In preclinical animal models, whereas the overexpression of Met and/or HGF has been shown to stimulate tumorigenesis and metastasis, downregulation of Met or HGF expression resulted in increased apoptosis and decreased tumor growth and blood vessel density (37-40). Moreover, Met interacts synergistically with VEGF to promote angiogenesis, cell proliferation and invasion (41). This occurs through the transcriptional upregulation of the hypoxia inducible factor-1α and amplified HGF signaling, that resulted in both induction of invasion and increased expression of VEGF (41).
HGF和Met在多种干细胞和前体细胞中存在高表达，但在成熟细胞中表达水平很低。在亚临床动物模型中，Met和/或HGF的过表达表现出对肿瘤生长和转移的刺激作用。对Met和HGF的下调导致了细胞凋亡的增加以及肿瘤成长速度和血管密度的降低。而且，Met能协调地作用于VEGF从而促进了血管生成、细胞增值和侵袭。通过对缺氧诱导因子(HIF-1α)转录下调和HGF的扩增，导致了侵袭的发生和VEGF表达的增加。

Met pathway is also one of the key players in the development of acquired resistance to VEGF pathway inhibitors: the inhibition of Met expression prevented hypoxia-induced invasion growth (42,43).
Met通路也在对VEGF抑制剂的耐药的产生过程中扮演了关键角色：对Met表达的抑制阻止了缺氧诱导的侵袭性生长。

The increased Met expression described in case of response to ionizing radiation through the ATM-NFκB signaling pathway, could lead to radioresistance and cancer invasion (44).
Met能够通过ATM-NFkB信号通路增加表达以阻止对电离辐射的响应，这可以导致对放疗的抵抗和肿瘤的侵袭

Met pathway and cross-talks
Met通路和与其他信号通路的交互作用

The cross-talk of Met with various signaling pathways  is described in literature and that one between Met and  EGFR/HER family receptors is particularly important in lung cancer (45-49).
Met与其他多种信号通路的交互作用已经在文献中得到了阐述，在肺癌中，Met和EGFR/HER家族的交互表现得特别重要。

Met and EGF family receptors are often described co-expressed  in  tumors and  transactivation of Met depends on elevated expression of EGFR  in many human  tumors (46,50,51). Conversely, HGF stimulation promotes transactivation of EGFR in multiple cell lines, including NSCLC (49).
在许多人类肿瘤中都发现了Met和EGF族受体的协同表达以及依赖于EGFR表达水平提升的Met转录活化。与此对应的，HGF的刺激也能在包括NSCLC在内的多种细胞系中促进EGFR的转录活化。

Cooperation between Met and EGFR occurs also indirectly: when Met activates Src, this lead to EGFR phosphorylation and the creation of docking sites for EGFR interactors involved in downstream signaling (52).
Met和EGFR的协同作用总是间接的：Met对Src的激活会导致EGFR的磷酸化以及涉及下游信号的EGFR交互子的停泊位点的建立。

Moreover,  through receptor cross-talk, Met exerts a key role in the development of resistance to EGFR family inhibitors. One example  is  the stimulation of HER-3 phosphorylation and signaling to Akt (a key signaling molecule required for cell survival and proliferation) when Met  is amplified and overexpressed  (53,54). Inhibition of Met in EGFR inhibitors resistant cells, either  in vitro or in vivo, promotes apoptosis, tumor growth reduction and signifcant necrosis (49,53).
而且，通过受体的交互作用，Met在对EGFR家族抑制剂耐药性发展的过程中也表现出了关键的作用。一个例子就是Met的扩展会刺激HER3的磷酸化和到Akt(细胞生存和增殖所需的一个关键的信号分子)的信号传递。在对EGFR抑制剂耐药的细胞中应用Met抑制剂，无论是体外还是体内实验，都促进了肿瘤细胞的凋亡、肿瘤生长速度的减缓以及显著的坏死。

Met and EGFR inhibitors combined together, cooperatively abrogate ErbB3 signaling activation (49). An alternative mechanism  in  this context  is  the Src-induced EGFR phosphorylation (52).
联合应用Met和EGFR抑制剂，能够协同地解除ErbB3的信号激活。另外一种机制是能阻止Src诱导的EGFR磷酸化。

Preclinical data also support that Met cross-talks and cooperates with other members of the EGF receptor family, including HER2, to enhance cell invasion and this lead to the possibility  to explore  therapeutic activity of dual Met and HER2 therapies (55,56).
临床前数据也支持Met与EGF家族其他成员的交互和协同作用，包括HER2，能够增强细胞的侵袭功能，这引起了对同时作用于Met和HER2的靶向治疗的探索。

Stimulation with both HGF and EGF enhances downstream activation of several signaling pathways including Akt, Erk and STAT3 in a way that Met inhibitors abolished their baseline phosphorylation (57,58).
HGF和EGF的共同刺激增强了下游多种信号通路的激活，其中包括Akt、Erk和STAT3，在这种情况下，Met抑制剂能够抑制它们的基础磷酸化。

The already mentioned interaction between decorin and LRIG1 proteins, promotes ligand-independent receptor downregulation and degradation of EGFR family members. Decorin binds to the EGFR family, inducing receptor dimerization, internalization and eventual lysosomal degradation, whereas LRIG1 and EGFR associated via  their extracellular domains, allow enhanced EGFR phosphorylation. Thus, Met promotes resistance to VEGFR and EGFR inhibitors (59,60).
之前已经提到过胶饰蛋白多糖和LRIG1蛋白能够促进独立于配体的Met受体下调和EGFR族的降解。胶饰蛋白多糖绑定到EGFR家族，诱导了受体的二聚化、内在化和溶酶体降解。尽管LRIG1与EGFR结合与它们的胞外域，也能增强EGFR的泛素化。因此，Met促进了对VEGFR和EGFR抑制剂的耐药性。

Cross-talk between Met and KRAS signaling has also been described both in preclinical and clinical findings (61,62). Met activates RAS directly or via a protein-tyrosine phosphatase (63). Similarly, PI3K could be directly activated by Met or indirectly by RAS protein (30).
Met与KRAS的交互作用同样在临床前和临床研究中被发现。Met能够直接激活RAS，或者通过蛋白激酶磷酸化酶间接地激活。类似的，PI3K能够被Met直接激活或者通过RAS间接激活。

Moreover, Met directly binds to and sequesters the Fas receptor. This interaction prevents Fas self-aggregation and ligand binding, thus inhibiting Fas activation and apoptosis (64).
而且，Met能够直接绑定并且隔离Fas受体。这种相互作用阻止了Fas的自聚集和配体绑定，因此抑制了Fas的激活和细胞的凋亡。

Finally, preclinical studies exploring a combination of anti-Met therapeutic agents with mTOR inhibitors have also demonstrated an increased growth suppression, compared to mTOR inhibitors alone (62).
最后，临床前研究探索了联合抗Met治疗与mTor抑制剂的应用，相对于单独使用mTor抑制剂，这种方案同样展现了对肿瘤生长抑制效果的增加，

Met plays also a functional role in signaling pathways mediated by other membrane proteins. Integrin-dependent signaling could trigger ligand-independent Met phosphorylation following cellular adhesion, and Met and integrins might have independent yet synergistic roles in cell  invasion. Plexins, single-pass  transmembrane receptors for semaphorins, acts cooperatively with Met for cell adhesion and migration (45).
Met在由其他膜蛋白介导的信号通路中扮演了功能性角色。整合素依赖的信号能够在细胞粘附之后促发独立于配体的Met磷酸化，在细胞侵袭过程中，Met和整合素具有相互独立且协同增效的作用。Plexins，一种单次跨膜信号素受体，与Met协同作用于细胞的粘附和迁移

MET and NSCLC
MET与NSCLC

Met receptor  is overexpressed  in both Small Cell Lung Cancer (SCLC) and NSCLC, mainly in  non-squamous histotype (65-67).
Met受体能在小细胞肺癌(SCLC)和非小细胞肺癌(NSCLC)中有过表达，在NSLCL中主要是非鳞癌。

Recent  tumor microarray expression analysis demonstrated a 72% Met expression in human lung cancer tissue and 40% Met receptor over-expression; such values are higher than in breast (16%) and ovarian cancer (31%), but lower than in renal (70%) and colorectal cancers (CRC; 78%)  (67). Phospho-Met expression  is  found  to be at  the highest levels in lung cancer (73%), followed by ovarian (33%), breast (23%), and renal (18%) cancer (67).
最近的肿瘤基因芯片表达分析表明，在72%的人类肺癌组织存在Met表达，有40%具有Met受体的过表达，该比例高于乳腺癌(16%)和卵巢癌(31%)，低于肾癌(70%)和结直肠癌(78%)。磷酸化Met表达水平在肺癌中最高(73%)，之后依次是卵巢癌(33%)、乳腺癌(23%)和肾癌(18%)。

Met gene amplification can guide the dependency of cell survival and proliferation upon the Met signaling, even in lung cancer cell lines. Blocking Met causes significant growth inhibition, G1-S arrest and apoptosis in cell lines harboring Met gene amplification. When Met is not amplifed, its levels of activation are low and cells are unable to grow (68)
在肺癌细胞系中，Met基因的扩展能够指导依赖于Met信号的细胞生存和增殖。在具有Met扩增的细胞系中，阻断Met能够导致显著的生长抑制， G1到S期的阻断和细胞的凋亡。当Met失去扩增时，其激活水平较低，细胞也无法生长。

Different studies have reported primary Met amplification to be in the wide range of 2% to 21%, in NSCLC lung adenocarcinomas, particularly in TKI-naive cohorts (69-72).
在肺腺癌中，特别是未接受过TKI的治疗的患者，不同的研究报道了原发的Met扩增的概率范围从2%到21%。

In lung cancer, Met receptor mutations were mainly found clustered in the non-tyrosine kinase domain, in the juxtamembrane (JM) domain and in the sema domain (67). These mutations are oncogenic activating variants, that result in a deletion in the juxtamembrane domain with enhanced oncogenic signaling, tumorigenicity, cell motility, and migration (27,73). Met kinase domain mutations have been found to be somatically selected in the metastatic tissues, compared with the primary solid cancers (74).
在肺癌中，Met受体突变主要聚集于非酪氨酸激酶域、近膜域以及sema域。这些突变是致癌激活的变种，这导致了近膜域的缺失从而增强了致癌信号传导、致瘤行、细胞移动以及迁移。相比原发病灶，Met激酶域的突变被发现有选择地存在于转移的组织中。.

Literature data are quite discordant on the prognostic value of Met over-expression, amplification and mutation.
数据表明，Met的过表达、扩增和突变对预后值来说存在不一致的影响。

The overexpression of circulating Met in patients with NSCLC has been strongly associated with early tumor recurrence and patients with adenocarcinoma and Met mplification have also demonstrated a trend for poor rognosis (69,75,76).
对于NSCLC患者来说，外周循环的Met过表达与早期肿瘤复发存在密切联系，肺腺癌患者和Met突变同样表现为较差的预后。

Concerning the correlation between Met FISH status and clinical characteristics, only Okuda and colleagues demonstrated an association with male gender and smoking status, showing also a relationship with high Met gene copy number (77). In the same trial, both FISH positive and gene amplified cases had a worse prognosis, although the difference was not statistically significant and among the Met FISH-positive NSCLCs, patients with gene amplification showed not significantly worse OS compared to those with high polysomy.
考虑到Met FISH状态与临床特征的联系，Okuda和同事发现，男性和吸烟状况与高Met拷贝数存在关联。在同一个临床试验中，同时具有FISH阳性和基因扩增的病例有更差的预后，虽然并未表现出统计学上的显著差异。在Met阳性的NSCLC患者中，相对具有多染色体型的患者，具有基因扩增的患者并未表现出显著降低的OS。

All FISH-positive cases had squamous histology, adenocarcinoma had Met amplification: high Met gene copy number tended to have shorter OS and PFS than those with low Met gene copy number, being this difference statistically significant only in the squamous histotype.
所有FISH阳性病例其组织学类型都是鳞癌，而腺癌具有Met扩增：高的Met基因拷贝数倾向于具有更短的OS和PFS，相比具有低拷贝数的患者；而这种差异只有在鳞癌中才表现得明显。

Moreover, at multivariate analysis done on squamous histology, increased Met gene copy number and Met amplification were confirmed to be independent poor prognostic factors.
进一步的，对鳞癌的多元分析显示，增加的Met基因拷贝数和Met扩增被确定为独立的较差的预后因子。

No significant difference in prognosis was found in atients having adenocarcinoma regardless Met FISH status in the korean study. In contrast, Beau-Faller and colleagues found a tendency toward shorter event-free survival in adenocarcinoma patients with increased Met gene copy umber, whereas Kanteti and colleagues demonstrated that the high Met gene copy number in adenocarcinoma was associated with a trend of better prognosis (69). However,
the above mentioned study has some critical methodology aspects as it was conducted on a small sample size and PCR was used as test and not FISH, done on DNA samples extracted from formalin-fixed paraffin-embedded (FFPE) archival tumor tissues (70).
来自韩国的研究显示，Met FISH的不同状态在肺腺癌患者中对预后的影响没有差异。与此相反的是，Beau-Faller与同事发现在具有增多的Met基因拷贝数的腺癌患者趋向于拥有较短的无事件生存期，但Kanteti与同事又发现在腺癌患者中，高Met基因拷贝数与更加的预后相关，但此研究存在一些方法学上的缺陷，一是样本太少，二是采用的PCR而不是FISH，来分析来自于存档肿瘤组织的福尔马林固定石蜡包埋样本中的DNA。

Capuzzo and colleagues found no patient with EGFR mutation was Met FISH positive, but increased Met gene copy number significantly correlated with EGFR FISH positive status (78).
Capuzzo与同事发现没有EGFR突变的患者同时具有Met FISH阳性，但Met基因拷贝数的增加与EGFR FISH阳性状态显著相关。

Acquired Met amplification has also been linked to approximately 22% of non-T790M mediated secondary gefitinib resistance in NSCLC patients, although it can also occur concurrently but independently (52,53,78-80).
获得性Met扩增存在于大约22%的非T790M介导的对吉非替尼耐药的NSCLC患者中，虽然Met与T790M能同时存在但它们彼此是独立的。

Using in vitro cell line models, the Met gene amplification in gefitinib-resistant cell clones was identified (53).
使用体外细胞系模型，Met基因扩增被发现存在于在对吉非替尼耐药细胞克隆中。

Rho and colleagues tried to demonstrate that Met activation, rather than gene amplification, is sufficient to promote EGFR resistance, but the activation appear to be secondary to increase passage numbers rather than to EGFR-Tki exposure (81).
Rho和同事尝试展示Met的激活状态而不是基因的扩增，是促进EGFR耐药的原因，但发现激活为传代数增加的次要表现，而不是对EGFR-TKi的暴露。

More recently, two prospective analyses have investigated the mechanism of EGFR-Tki resistance through the tissue rebiopsy: high Met gene copy number was found in 11% and 5% of the tissue samples, respectively (82,83).
最近，两个前瞻分析通过组织再活检来研究EGFR-TKI的耐药机制：高的Met基因拷贝数分别在11%与5%的组织样本中被发现。

FIN

Poster Presentations - Inhibition of Kinase Signaling 1

Abstract 928: Volitinib (HMPL504), a novel, selective and potent cMET inhibitor, is efficacious in primary tumor models of cMET-driven gastric cancer.
Paul R. Gavine1, Shiming Fan2, Haihua Fu1, Lu Han1, Yuan Jie Liu1, Jing Lv1, Weiguo Qing2, Yongxin Ren2, Weiguo Su2, Xinying Su1, Huiying Wang1, Liang Xie1, Shirlian Xu1, Wen Xu2, XiaoLu Yin1, Yongjuan Yu2, Tianwei Zhang1, and Q.May Wang2
1AstraZeneca, Shanghai, China;
2Hutchison MediPharma Ltd, Shanghai, China.

Gastric cancer (GC) incidence rates are amongst the highest in Asian countries including; China, Japan and Korea(1). 5-year survival rates in early stage disease have improved through aggressive combinations of surgery and chemo/radiotherapy. In late stage disease however, despite Her2 molecular segmentation and trastuzumab therapy, prognosis remains dismal and novel therapeutic options are urgently required(2).

The MET oncogene encodes the receptor tyrosine kinase for hepatocyte growth factor and controls genetic programs leading to cell growth, invasion and survival. Dysregulation of MET signaling is a common feature of a diverse range of human tumor types and thus represents a highly competitive and attractive therapeutic target. Volitinib (HMPL-504) is an orally bioavailable, highly selective and potent small molecule ATP-competitive inhibitor, which inhibits cMET autophosphorylation and downstream signaling (3). Volitinib is currently in Phase I clinical development. To evaluate the utility of volitinib in treating patients with GC, we established the incidence of cMET amplification and overexpression and attempted to correlate this with response to volitinib in primary GC tumor models. Elevated cMET gene copy number (amplification 5%, high polysomy 13%), and protein overexpression (12%, cases > IHC 2+, 16% > IHC1+) were detected in a cohort of 217 Chinese GC samples using fluorescent in situ hybridization (FISH) and immunohistochemical (IHC) approaches. In vitro proliferation assays were performed on a panel of 26 GC cell lines and profound sensitivity to volitinib was demonstrated in lines harboring elevated cMET gene copy number (GI50 range 6 to 49nM). In the cMET amplified GC xenograft model, Hs746t, once-daily oral dosing of volitinib (2.5mg/kg) elicited potent anti-tumour activity at well-tolerated doses (97% tumour growth inhibition after 16 days dosing, P<0.0001) which correlated well with pharmacodynamic modulation of phospho-cMET signaling. To strengthen the translational relevance of these data, a panel of cMET amplified primary GC models were identified and established. In these models, volitinib demonstrated potent tumor growth inhibition or regressions (90% and 84% TGI at 10mg/kg/qd, all P<0.0001), correlated with pharmacodynamic modulation of tumor phospho-cMET. In contrast, 10mg/kg/qd volitinib was inactive (18% TGI, P=0.2405) in a cMET non-amplified control model. We also evaluated the activity of volitinib in combination with docetaxel, a standard of care chemotherapeutic commonly used in the treatment of gastric cancer. In model Hs746t, volitinib demonstrated additive benefit when used with docetaxel at well tolerated doses. These data support the potential clinical utility of volitinib as a selective agent for the therapeutic treatment of gastric cancers harboring dysregulated cMET signaling.
http://cancerres.aacrjournals.or ... eetingAbstracts/928

Abstract 3371: Preclinical disposition and pharmacokinetics of volitinib, a novel selective cMet inhibitor .
Yi Gu, Yang Sai, Jian Wang, Sumei Xia, Guanglin Wang, Yuansheng Zhao, Li Zhang, Wenqing Yang, Guangxiu Dai, Weihan Zhang, Qisun Gong, Zhenping Tian, and Weiguo Su
Hutchison MediPharma Limited, Shanghai, China.

Volitinib is a novel selective cMet inhibitor. This study is to evaluate its preclinical ADME/PK profile. Volitinib has high membrane permeability (Papp (A>B) 28x10–6 cm/s) without efflux transport across Caco-2 cell monolayer and exhibits negligible P-gp inhibition (IC50 > 17 μM). Metabolic stability of volitinib in liver microsomes and S9 fractions of rat, dog, monkey and human was evaluated. Five phase I metabolites were observed in liver microsomes and S9 fractions of different species, and three major metabolites resulted from demethylation (M1), hydroxylation (M2) and mono-oxygenation (M3) were found to be mediated by multiple enzymes, including CYP450s and aldehyde oxidase. Rat was the most similar species to human in terms of the in vitro metabolism and metabolite profile. Metabolism is the main route of elimination for volitinib in rat due to the fact that the fecal, urinary and biliary excretion of the parent volitinib accounted for <2% of the dose. The total of 16 phase I metabolites and 8 phase II metabolites were identified in plasma and excreta of rat. M22, a sulfate conjugate of a monooxidized metabolite M5, dominated with the abundance in all tested matrices. Demethylation to M2 excreted in urine was also an important elimination pathway in rat. Volitinib showed no significant reversible or mechanism-based CYP inhibition in human liver microsomes, and no induction of CYP1A2 and CYP3A4 in human hepatocytes. Volitinib had moderate plasma protein binding rate (60%70% in rat, dog, and human; 40% in mouse; 80% in monkey) and exhibited wide distribution to different organs in rat, with high exposures in liver and kidney, very low in brain, spinal cord and testis comparing to the plasma level. In PK studies in mouse, rat and dog, Volitinib showed the rapid oral absorption (Tmax<2.5 h) with high exposures and the acceptable bioavailability at 27.2%, 42.6% and 86.3%, respectively. The in vivo clearance (CL) was 11.0, 11.8 and 3.5 mL/min/kg in mouse, rat and dog, respectively, revealing a low extraction ratio. The volume of distribution in steady state (Vss) was 0.4, 1.4 and 1.4 L/kg in those species, respectively, indicating a moderate to low distribution pattern. Volitinib also displayed linear pharmacokinetics (PK) in the dose ranges of 1 to 25 mg/kg in rat and 2 to 10 mg/kg in dog. Food hardly affected its PK profile in dog. In contrast, volitinib in monkey showed a notably high extraction ratio (CL=17.2 mL/min/kg) consistent with the in vitro metabolism result. Considering the rapid absorption of volitinib (Tmax=1.9 h) and moderately low distribution (Vss=0.7 L/kg), the poor oral bioavailability (1.9%) of volitinib in monkey is considered to be the result of excessive first-pass extraction. Overall, volitinib exhibited favorable preclinical PK/ADME properties.

Abstract 971: Synergistic effect of c-Met inhibitor volitinib in combination with EGFR inhibitor Gefitnib on EGFR-TKI resistant NSCLC model HCC827C4R harboring acquired Met gene amplification.
Feng Zhou, Yongxin Ren, Yumin Cui, Hanyang Chen, Longxian Jiao, Guangxiu Dai, Shiming Fan, Junen Sun, Yongjuan Yu, Yang Sai, Yi Gu, Weiguo Qing, and Weiguo Su
Hutchison MediPharma Ltd., Shanghai, China.

It is well recognized that non-small cell lung carcinoma (NSCLC) patients with activating EGFR mutations will develop drug resistance after receiving EGFR-tyrosine kinase inhibitors (EGFR-TKI). About 20% of those patients with TKI resistance were identified to harbor Met gene amplification. The aim of this study includes two aspects: a) generating an acquired c-Met amplified EGFR-TKI resistant tumor line in preclinical setting, and b) exploring combination effect of c-met inhibitor volitinib and EGFR inhibitor gefitinib on the new tumor line. Volitinib is a novel, highly potent and selective c-Met inhibitor, currently being evaluated in the phase I clinical trial.

HCC827(exon 19 del E746-A750), a human NSCLC cell line, was treated with increasing concentrations of EGFR inhibitor for about 6 months and gradually produced the resistance to EGFR-TKIs, such as gefitinib and erlotinib. One of the subclones, HCC827C4R was isolated and was confirmed to carry Met gene amplification in comparison to parent cell line HCC827. It was not sensitive to volitinib treatment in cell survival assay due to dual activation of EGFR and c-Met pathways. The results from signal pathway study demonstrated that in HCC827C4R cells, volitinib or gefitinib alone only inhibited the phosphorylation of c-Met or EGFR, respectively, but had no effect on the activation of downstream molecules such as Akt and ERK which drive tumor cell proliferation and other cell functions. In contrast, combination of volitinib and gefitinib significantly inhibited phosphorylation of EGFR, c-Met, Akt and ERK in HCC827C4R, and consequently led to a synergistic effect on inhibiting tumor cell growth in vitro. These results were further confirmed in HCC827C4R xenograft model in vivo at clinically relevant doses. Combination of volitinib and gefitinib induced significant tumor regression and displayed synergistic effect compared to treatment by either gefitinib or volitinib alone. Consistent with in vitro results, combination group strongly inhibited the downstream Akt and ERK phosphorylation. In addition, combination treatment was well tolerant and no significant drug-drug exposure interaction was observed. These data indicated that both c-Met and EGFR could contribute to activating downstream signaling pathway and control HCC827C4R cell growth. Blocking either pathway may not be strong enough to stop tumor growth.

In conclusion, a cell line with activating EGFR mutation and c-Met gene amplification was generated with resistance to gefitinib and insensitivity to volitinib. The combination treatment with volitinib and an EGFR inhibitor gefitinib was highly effective in vitro and in vivo, suggesting that such combination could provide a safe and effective treatment in clinics for this particular patient population.

六楼的论文大概摘要

T790M and acquired resistance of EGFR TKI: a literature review of clinical reports
T790M和对EGFR TKI的获得性耐药：临床报告的书面回顾

Comparison of T790M detection methods
T790M检测方法比较

In most cases, DS plus PCR were used to detect EGFR mutation status including T790M. Generally, PCR, especially mutant-enriched PCR is a more sensitive and highly specific assay that can detect one copy of mutant allele among as many as 103 to 104 copies of wild-type alleles when compared to direct DNA sequencing. The use of this assay has been validated with various clinical specimens, including biopsy and pleural fluid specimens (31).
在绝大多数案例中，通常采用DS(直接测序，Direct Sequencing)加上PCR(聚合酶链反应，Polymerase Chain Reaction)来检测包括T790M在内的EGFR突变状态。通常来说，PCR特别是突变富集PCR(mutant-enriched PCR)具有更高的敏感度，对比直接DNA测序来说，其具有的高度特定的基因芯片可以在多达103至104份野生型等位基因中识别出1份突变基因。已经在多份临床样本中验证了该基因芯片的使用，包括组织活检样本和胸腔积液样本。

The use of Scorpion Amplification Refractory Mutation System (SARM) was also reported, in which the two technologies ARMS and Scorpion were combined to detect T790M in real-time PCR reactions (12). Compared to traditional PCR, SARM system was more sensitive.
同样报告了对于蝎形探针扩增阻滞突变系统(Scorpion Amplification Refractory Mutation System, SARM)的使用，联合ARMS和蝎型探针在实时PCR反应中(real-time PCR)检测T790M突变。对于传统PCR来说，SARM系统具有更高的敏感性。

In one clinical study, both SARM and WAVE/Surveyor methods were employed for the detection of EGFR activation and resistant mutations using plasma DNA from TKI resistant patients. Eight out of nine T790M positive patients were detected by SARM, while WAVE-Surveyor system detected four, and three were detected by both methods. Whole genome amplification of samples seems to have the greatest effect on the detection of T790M. Furthermore, whole genome amplification of DNA samples was also investigated to determine if the detection of additional EGFR mutations would be facilitated. For EGFR del E746_A750 and L858R, whole genome amplification identified only four additional patients with mutations, whereas for EGFR T790, whole genome amplification resulted in the identification of 10 additional patients (P = 0.011). This may be explained by the fact that T790M often exists as a rare allele and thus may go undetected in the absence of whole genome amplification. The results suggest that whole genome amplification should be incorporated in future noninvasive method in order to aid in monitoring drug resistance and in directing the course of subsequent therapy (32).
在一个临床研究中，同时使用SARM和WAVW/Surveyor两种方法来检测来自耐药患者血液DNA中的EGFR激活突变和耐药突变。九例T790M阳性患者中的八例被SARM检测出，WAVE-Surveyor系统检测出了4例，3例被两种方法同时检测出。样本的全基因组扩增显示对于T790M的检测具有最好的效果。进一步的，对于DNA样本的全基因组扩增同样被研究以确定能够容易地检测额外的EGFR突变。对于EGFR E746_A750缺失突变和L858R点突变来说，全基因组扩增只识别出了4例额外的突变患者，但对于EGFR T790，全基因组扩增识别出了额外10例患者(P=0.011)。这可解释为T790M是一种不常见的突变，在无全基因组扩增扩增时通常无法检出。该结果建议全基因组扩增应该联合未来非侵入式检测方法，以监控耐药性的产生以及指导随后的治疗方案。

In general, PCR, especially mutant PCR is more sensitive than direct sequencing. Since T790M is often present as a minor allele, whole genome amplification could improve detection of T790M.
通常来说，PCR，特别是突变PCR具有比直接测序更高的敏感度。因为T790M通常作为少见突变存在，全基因组扩增能提高T790M的检出率。

To sum up, acquired-resistant patients usually undergo a dramatic response or partial response for around 10 months before they develop resistance to TKI. Few patients among them can be detected T790M positive; but after the resistance developed, T790M mutations account for half of these cases. Meanwhile, in our analysis, EGFR T790M always coexist with other resistance mutations such as MET amplification. The switch therapy from gefitinib to erlotinib might be useful for those originally well-responded patients. Irreversible TKIs in development might also show promises in overcoming T790M-induced resistance. The use of high-sensitivity analytical techniques may aid in finding suitable individualized therapy for patients based on their mutational status.
概括来讲，获得性耐药的患者通常在对TKI产生耐药的前10个月左右显示出非常好的或者部分的响应，他们中的一少部分可以检测出T790M阳性。但在耐药发展之后，一半的患者都具有T790M。同时，在我们的分析中，EGFR T790M总是伴随着其他耐药突变比如MET扩增。从吉非替尼切换到厄洛替尼的方案可能适合于初始响应较好的患者。在研发中的不可逆TKIs同样显示出能克服T790M导致的耐药。高敏感性分析技术的应用能基于患者的突变状态来寻找适合每位患者的个体化治疗方案。

---

上面是老马粘贴文字部分的内容，我再说说这篇论文的大概意思

这篇论文是由南京大学医学院和金陵医院的研究者们于2011年撰写的一篇回顾性质的文章，当时afatinib还处于临床试验阶段，可用的EGFR TKI就只有易瑞沙和特罗凯。这篇文章收集了从2005年1月到2010年5月期间所有关于T790M和耐药性的包含病例报告的临床论文(去掉了基础研究比如动物实验和体外实验的论文)，主要想了解几个问题：1.T790M在耐药前和耐药后所占的比例；2.从易瑞沙切换到特罗凯是否可行；3.有哪些检测T790M的方法，分别有什么特点；4.MET和T790M的关系。

论文的主体包含了一个病例报告和一个临床报告。

病例报告回顾了19位T790M阳性的患者的资料，获得的信息是：

• 大部分(n=14)患者具有不同类型的EGFR敏感突变如外显子19缺失、L861Q和L858R
• 在应用TKI治疗前只有1位患者检测出T790M阳性
• 所有患者(n=19)在耐药后都检测出了T790M
• 显示T790M能够与敏感突变共存
• 其中有4个病例为细支气管肺泡癌(BAC)，分析表明在该病例类型的腺癌中，EGFR突变出现的频率特别高
  

临床报告主要为以下几点内容：

• T790M在未接受TKI治疗的患者中的情况：
  在7个临床报告共计845例患者中，只有4例在接受TKI治疗前检测出了T790M，这个比例是0.47%(4/845)。表明原发T790M是一种很少见的突变类型。所有4例患者都具有T790M/L858R双突变，这是种非常具有侵略性的肿瘤类型，所有的患者随后很快就出现了肿瘤的复发最后导致了死亡。(注：那时候没有更多的针对T790M导致耐药的用药经验，以及缺乏第二代EGFR TKI)
• T790M在TKI耐药的患者中的情况：
  在来自9个临床报告共计169例TKI耐药的患者中，采集到了158份TKI治疗失败后的组织样本，其中有82份具有T790M(51.9%)，与之前报告的约半数的耐药患者具有T790M相一致，且与性别、吸烟状态、病理学类型和种族无关。
• 使用厄洛替尼治疗对吉非替尼耐药和具有获得性T790M的患者：
  大部分(>83%)对吉非替尼耐药的患者在接受厄洛替尼之后的头二至四个月出现了影像学的进展。但与此相反的是，一部分患者却出现了肿瘤的缩小和部分缓解。类似的，一个Phase II的临床试验表明，在具有野生型EGFR且在接受吉非替尼治疗时病情稳定的患者，应用厄洛替尼治疗是一个潜在的治疗选择。同时，在高度选择的患者亚组中(女性、亚裔、非吸烟者、腺癌类型)，厄洛替尼的有效性还存在争议。一个研究报告厄洛替尼缺乏令人满意的有效性，另一个研究报告在一线对吉非替尼具有良好响应的患者，在应用厄洛替尼作挽救治疗(salvage treatment)时疾病控制率可达66.7%。因为最好的响应都只能是病情稳定(SD），所以应该将厄洛替尼应用于对吉非替尼具有较好响应的患者中。(注：再说一遍，那时候二代TKI还处于临床，所以在现在有2992和299804的情况下，不建议在易耐药时首选特)
• T790M和MET扩增在未接受TKI和对TKI耐药的患者中的情况：
  在7个临床报告中收集到47份未接受TKI治疗和140份TKI治疗后的组织样本。在所有未接受TKI治疗的样本中检测到4例具有MET扩增，在治疗后的样本中检测到了23例具有MET扩增。T790M未在未接受治疗的样本中检出，但在治疗后的样本中检测出了66例。9位患者同时具有MET扩增和T790M，该比例在具有MET扩增的患者中占39.1%。MET扩增在未接受治疗和接受治疗且耐药的患者中的比例分别为3.48%(4/115)和15.9%(23/145)，表明MET扩增是仅次于T790M的耐药原因之一，提示当时正在研发中的不可逆EGFR TKI可能对这部分含有MET扩增的患者无效。
• T790M检测方法对比：
  见前面的翻译内容
  

讨论：
第一例T790M于2005年在一位71岁的老年男性患者中被发现，当时已经接受吉非替尼的治疗两年了。在复发后对其肿瘤活检样本的DNA测序揭示了T790M的存在。值得深究的是，在其他激酶中也观察到了类似于T790M的获得性耐药突变。有研究指出，T790M更多发生于晚期肿瘤中，提示在晚期NSCLC中存在更多的染色体组不稳定性。表明T790M并不是肿瘤发生和细胞增值的主要驱动基因。
论文撰写时，还不太清楚T790M导致耐药的机理。据推测是因为发生在碱基对上的C到T的变换，引起790号位置苏氨酸到甲硫氨酸的置换，从而导致较大的甲硫氨酸侧链的生成，对TKI产生了空间位阻，从而是EGFR的激酶域的催化口袋(catalytic pocket)对ATP的结合性得到增强。
对于文中讨论的10个由T790M导致吉非替尼耐药并且切换至厄洛替尼的病例，分析并未达成一致的结论。但在大多数病例中，切换至厄洛替尼的方案都是失败的。部分患者从厄洛替尼中受益可能存在的解释有：1.肿瘤异质性导致对两种TKI存在不同的敏感度；2.厄洛替尼具有与吉非替尼不同的药代动力学；3.存在选择性群体。需要更多的临床试验来验证这些解释。
对于T790M检测方法来说，非侵入式检测还是不应代替肿瘤样本(这里非侵入式是指血液中游离的DNA检测，而不是循环肿瘤细胞)。主要原因是：1.很难确定分离出来的DNA是来源于肿瘤细胞的；2.很难确定是代表了大部分肿瘤细胞的突变(肿瘤异质性)。特别要注意的是从发展至耐药到采集血液样本的时间。在未来，非侵入式检测会具有更大的应用前景。
最后还展望了一下还在研发中的不可逆抑制剂，基于现在已经对2992/299804有了充分的了解和应用，这部分就不翻译了

FIN

七楼的摘要的翻译

Abstract 4112: De novo EGFR T790M mutation modifies outcome to second-line erlotinib in non-small cell lung cancer (NSCLC) according to metastatic site and upfront chemotherapy

摘要 4112：新生EGFR T790M突变改变了那些具有远端转移灶且最开始接受化疗的NSCLC患者中二线使用厄洛替尼的结局

Rafael Rosell, Miguel Angel Molina, Jose Javier Sanchez, Miquel Taron1, Susana Benlloch, Teresa Moran, Enric Carcereny, Felipe Cardenal, Bartomeu Massuti, and Ignacio Magri

EGFR T790M mutation is associated with shorter progression-free survival (PFS) (12 months [m] vs 18 m; P=0.02). We hypothesized that the site of metastases (mets) and/or prior chemotherapy could also influence outcome in these p.

EGFR T790M突变与较短的无进展生存期相关(PFS)(12个月 vs 18个月; P=0.002)。我们假设远端转移灶和/或之前接受的化疗会影响具有T790M患者的结局。

Methods: The T790M mutation was assessed in 129 advanced NSCLC p by TaqMan assay in the presence of a peptide-nucleic acid designed to inhibit the amplification of the wild-type allele.

方法：使用TaqMan asssay通过肽核酸(peptide-nucleic acid)抑制野生型基因的扩增来测定129晚期NSCLC患者的T790M状态。

Results: De novo T790M mutations were identified in 35% (45 of 129) of EGFR-mutant p before receiving erlotinib. The T790M mutation was detected more frequently in p with bone mets (35.6% vs 16.7%; P=0.03). PFS was 20 m for 58 p with a deletion in EGFR exon 19 (del 19) but without the T790M mutation vs 12 m for 23 p with both del 19 and the T790M mutation (P=0.03), but with no difference in MS between these two groups (31 m vs 29 m; P=0.56). PFS was 15 m for 26 p with the L858R mutation but without the T790M mutation vs 16 m for 22 p with both the L858R and T790M mutations (P=0.83), with no difference in MS between these two groups (27 m vs 21 m; P=0.81). When p with T790M were divided according to the presence of brain mets, PFS was 1 m for 4 p with brain mets vs 13 m for 41 p without brain mets (P=0.002), while MS was 6 m for p with brain mets vs 36 m for those without (P=0.009). No effect on PFS or MS was observed in p with the T790M mutation according to lung, liver, pleura or bone mets. In the multivariate analysis, the presence of the T790M mutation did not increase the risk of short MS (HR, 1.3; P=0.49), while having received prior chemotherapy was associated with longer MS (HR, 0.48; P=0.02).

结果：新生T790M突变在35%(45 of 129)的具有EGFR突变且还未接受厄洛替尼的患者中检出。T790M突变更多的存在于具有骨转移的患者(35.6% vs 16.7%; P=0.03)。58位具有EGFR外显子19缺失突变但没有T790M突变的患者的PFS是20个月，对比那些同时具有19突变和T790M的患者的PFS是12个月。但两个组的中位生存期(MS, middle survival)并未存在差异(31个月 vs 29个月; P=0.83)。26位具有L858R但没有T790M的患者的PFS是15个月，对比同时具有L858R和T790M的患者的PFS为16个月，这两个组的中位生存期也不存在显著的差异(27个月 vs 21个月; P=0.81)。将具有T790M的患者根据脑转移的状态分为两个组，1位具有脑转移的T790M患者PFS为1个月，对比不具有脑转移的41位患者其PFS为13个月(P=0.002)，两组的中位生存期分别为6个月和36个月(P=0.009)。在T790M患者中并未观察到肺部、肝脏、胸膜和骨转移对总生存期和PFS的影响。通过多变量分析，T790M的存在并未增加缩短总生存期的危险(HR, 1.3; P=0.49)，而那些之前接受过化疗的患者具有更长的总生存期(HR, 0.48; P=0.02)。

Conclusions: The de novo T790M mutation is a marker for poor prognosis in p with brain mets. Upfront chemotherapy can play a role in the management of NSCLC p with the de novo T790M mutation.

总结：新生T790M在具有脑转移的患者中是一个预后较差的标记物。最开始接受的化疗在具有新生T790M的NSCLC患者中扮演了控制疾病的角色。

---

这里有几个地方需要解释一下，不然可能会误导部分病友。

• de novo是新生的意思，在这里可以理解是原发的T790M突变，即是那些还未接受TKI治疗的患者中检测到的突变，而不是指导致耐药的二次突变。
• 我们看到这篇摘要里说明原发T790M能够在35%的EGFR突变患者中检出，这个比例大大超过了以往的数据，这主要是因为检测方法不同造成的。*
  

*:关于不同的检测方法对于原发T790M检出率不同可以参考以下论文：
Pretreatment Epidermal Growth Factor Receptor (EGFR) T790M Mutation Predicts Shorter EGFR Tyrosine Kinase Inhibitor Response Duration in Patients With Non–Small-Cell Lung Cancer

在未经的NSCLC患者中EGFR T790M突变提示较短的EGFR TKI响应时间

Kang-Yi Su, Hsuan-Yu Chen, Ker-Chau Li, Min-Liang Kuo, James Chih-Hsin Yang, Wing-Kai Chan, Bing-Ching Ho, Gee-Chen Chang, Jin-Yuan Shih, Sung-Liang Yu, and Pan-Chyr Yang

Purpose
Patients with non–small-cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR)–activating mutations have excellent response to EGFR tyrosine kinase inhibitors (TKIs), but T790M mutation accounts for most TKI drug resistance. This study used highly sensitive methods to detect T790M before and after TKI therapy and investigated the association of T790M and its mutation frequencies with clinical outcome.

Patients and Methods
Direct sequencing, matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) and next-generation sequencing (NGS) were used to assess T790M in the following two cohorts of patients with NSCLC: TKI-naive patients (n = 107) and TKI-treated patients (n = 85). Results were correlated with TKI treatment response and survival.

Results
MALDI-TOF MS was highly sensitive in detecting and quantifying the frequency of EGFRactivating mutations and T790M (detection limits, 0.4% to 2.2%). MALDI-TOF MS identified more T790M than direct sequencing in TKI-naive patients with NSCLC (27 of 107 patients, 25.2% v three of 107 patients, 2.8%, respectively; P = .001) and in TKI-treated patients (before TKI: 23 of 73 patients, 31.5% v two of 73 patients, 2.7%, respectively; P = .001; and after TKI: 10 of 12 patients, 83.3% v four of 12 patients, 33.3%, respectively; P = .0143). The EGFR mutations and their frequencies were confirmed by NGS. T790M was an independent predictor of decreased progression-free survival (PFS) in patients with NSCLC who received TKI treatment (P = .05, multivariate Cox regression).

Conclusion
T790M may not be a rare event before or after TKI therapy in patients with NSCLC with EGFR-activating mutations. The pretreatment T790M mutation was associated with shorter PFS with EGFR TKI therapy in patients with NSCLC.

JCO.2011.38.3224.full.pdf (553.54 KB, 下载次数: 120)

2014-1-6 12:26 上传

点击文件名下载附件

这篇论文采用了MALDI-TOF MS(基质辅助激光解吸电离飞行时间质谱仪)来检测未经治疗的患者中存在T790M的概率，结果这个概率大于直接测序(25.2% vs 2.8%)，在采用TKI治疗后，有多达83.3%的患者存在T790M。




Acquired Resistance to EGFR Tyrosine Kinase Inhibitors in EGFR-Mutant Lung Cancer: Distinct Natural History of Patients with Tumors Harboring the T790M Mutation

在EGFR突变的肺癌患者中对EGFR TKI的获得性耐药：在具有T790M突变的肿瘤患者不同的自然病程

Geoffrey R. Oxnard, Maria E. Arcila, Camelia S. Sima, et al.

Purpose: Patients with epidermal growth factor receptor (EGFR)-mutant lung adenocarcinoma develop acquired resistance to EGFR tyrosine kinase inhibitors (TKI) after a median of 10 to 16 months. In half of these cases, a second EGFR mutation, T790M, underlies acquired resistance. We undertook this study to examine the clinical course of patients harboring the T790M mutation following progression on TKI.

Experimental Design: EGFR-mutant lung cancer patients with acquired resistance to EGFR TKIs were identified as part of a prospective rebiopsy protocol in which postprogression tumor specimens were collected for molecular analysis. Postprogression survival and characteristics of disease progression were compared in patients with and without T790M.

Results: We identified T790M in the initial rebiopsy specimens from 58 of 93 patients (62%, 95% CI:52–72). T790M was more common in biopsies of lung/pleura tissue and lymph nodes than in more distant sites (P = 0.014). Median postprogression survival was 16 months (interquartile range &frac14; 9–29 months); patients with T790M had a significantly longer postprogression survival (P = 0.036). Patients without T790M more often progressed in a previously uninvolved organ system (P = 0.014) and exhibited a poorer performance status at time of progression (P = 0.007).

Conclusions: Among patients with acquired resistance to EGFR TKIs, the presence of T790M defines a linical subset with a relatively favorable prognosis and more indolent progression. Knowledge of T790M tatus is therefore important both for the clinical care of these patients and for the optimal design and nterpretation of clinical trials in this setting. Clin Cancer Res; 17(6); 1616–22. 2010 AACR.

1616.full.pdf (431.72 KB, 下载次数: 145)

2014-1-6 12:39 上传

点击文件名下载附件

在这篇论文也提到了T790M检出率依赖于不同的检测方法：though the prevalence of "de novo T790M" can vary depending on the detection method employed. 该论文中使用的是锁核酸探针PCR，其敏感度能在0.1%的DNA中侦测到T790M(hich suppresses amplification of the ild-type allele and allows detection of T790M when resent in as little as 0.1% of DNA)。使用这种具有更高敏感度的方法在62%的TKI耐药的患者中检测到了T790M，这个比例高于直接测序法。

FIN

MET-negative patients—eclipsing benefits.pdf (76.14 KB, 下载次数: 113)

2014-1-5 12:44 上传

点击文件名下载附件

Although the EGFR inhibitor erlotinib has improved survival in patients with non-small-cell lung cancer (NSCLC), resistance eventually develops. Data from preclinical models support at least additive effects when anti-MET and anti-EGFR therapies are combined. Thus, David&nbsp;Spigel and coauthors conducted a global, randomized, placebo-controlled phase&nbsp;II study in patients with recurrent NSCLC to compare erlotinib and onartuzumab with erlotinib and placebo. “As erlotinib is approved in the refractory setting in unselected patients with NSCLC, the goal of this trial was to learn if the addition of a novel MET
antibody could improve upon efficacy”, explains Spigel.No difference in progression-free survival was found in the intention-to-treat population. However, when MET-positive patients were assessed, a significant reduction in the risk of disease progression was noted compared with patients who
were MET-negative. In MET-positive patients, the combination resulted in an overall survival improvement three times greater than in the placebo arm. Crucially, the exact opposite effect was observed in patients with MET-negative tumours. Patients assigned to onartuzumab had significantly shorter overall survival compared with patients receiving placebo (median 8.1&nbsp;months versus 15.3&nbsp;months). Most adverse events were comparable
between the arms, although peripheral oedema was increased in patients treated with onartuzumab.The addition of onartuzumab in MET-positive patients resulted in a similar median survival as that observed in MET-negative patients receiving erlotinib alone, indicating that the combination in MET-positive
patients abrogated the&nbsp;negative&nbsp;prognostic effect seen in MET-negative patients.
A&nbsp;phase III trial in MET-positive patients with this combination is ongoing. This study underscores the importance of optimal patient selection according to biomarker status for the appropriate allocation of targeted therapies.