吉非替尼和厄洛替尼耐药机制

吉非替尼和厄洛替尼是首批用于晚期非小细胞肺癌(NSCLC)的分子靶向药物,尽管治疗效果显著,但最终多数患者均会发生耐药.近年来研究表明,其耐药机制与表皮生长因子受体(EGFR)二次突变、其他酪氨酸激酶家族受体异常活化及信号通路成分或调节因子基因表达的改变等有关.另有研究表明,可能与EGFR受体内化及肿瘤微环境改变也有相关性.进一步研究其耐药机制,并寻找克服或逆转耐药的方法、开发新的靶向药物已成为肺癌治疗领域的前沿课题.     

厄洛替尼单药治疗EGFR突变的晚期NSCLC患者试验汇合分析

背景与目的 厄洛替尼被全球多个国家批准用于晚期非小细胞肺癌(non-small cell lung cancer,NSCLC)患者的二、三线治疗.有报道显示EGFR突变的患者应用厄洛替尼治疗疗效更好.本文拟探讨厄洛替尼单药治疗EGFR突变晚期NSCLC患者的疗效.方法 计算机检索MEDLINE(2004-2009)、CBMdjc(2004-2008)、CNKI(2004-2008),互联网检索以及纳入试验的参考文献.纳入相关临床试验,提取并汇总试验结果.结果 共纳入研究7篇,包括晚期非小细胞肺癌患者463例.厄洛替尼单药治疗EGFR突变的晚期非小细胞肺癌患者,有效率达到66%,1年生存率达到73%,2年生存率达到5396,中位生存时间23个月以上,无进展生存时间8.6个月以上.结论 在当前研究的基础上,厄洛替尼单药一线和二线治疗EGFR突变的晚期NSCLC有效率高,无进展生存期和总生存期长,可以推荐作为EGFR突变的晚期NSCLC的首选治疗.尚需要更详尽的证据评价厄洛替尼单药方案或厄洛替尼与化疗联合方案与标准含铂化疗方案在治疗晚期NSCLC中的地位.     

干扰素、亚砷酸联合酪氨酸激酶抑制剂治疗原发T315I突变慢性粒细胞白血病一例并文献复习

目的 探讨干扰素、亚砷酸联合酪氨酸激酶抑制剂(TKI)治疗原发T315I突变慢性粒细胞白血病(CML)的效果.方法 应用干扰素、亚砷酸联合TKI(伊马替尼)治疗1例原发T315I突变的CML患者,并进行文献复习.结果 CML加速期患者应用亚砷酸联合伊马替尼治疗1周后达完全血液学缓解;更换为干扰素联合尼洛替尼治疗6个月后,达部分细胞遗传学缓解,T315I突变消失.结论 干扰素、亚砷酸联合TKI可作为原发T315I突变CML的有效治疗手段.     

表皮生长因子受体酪氨酸激酶突变对于非小细胞肺癌疗效影响的研究进展

随着肺癌发病机制研究的深入,靶向治疗在NSCLC治疗中的地位日渐重要.其中,以厄洛替尼和吉非替尼为代表的表皮生长因子受体酪氨酸激酶抑制剂(epidermal growth factor receptor tyrosine kinase inhibitor,EGFR TKI)的靶向药物取得了一定的疗效.     

厄洛替尼治疗失败后埃克替尼靶向治疗晚期非小细胞肺癌1例报道

厄洛替尼和埃克替尼是一种选择性表皮生长因子受体（epidermal growth factor receptor,EGFR）——酪氨酸激酶抑制剂（tyrosine kinase inhibitor,TKI）,在进展期非小细胞肺癌（NSCLC）中具有靶向治疗作用。靶向药物治疗一般作为二线或三线用药,其治疗失败后很少有行之有效的治疗策略。本文报道1例晚期NSCLC厄洛替尼治疗失败后采用埃克替尼靶向治疗有效的病例。     

c-Met/ErbB3/PI3K信号通路在肺癌EGFR-TKI获得性耐药中的研究进展

0引言目前小分子酪氨酸激酶抑制剂(tyrosine kinase inhibitor,TKI)包括吉非替尼(Gefitinib)和厄洛替尼(Erlotinb),作为二线药物在非小细胞肺癌的临床治疗中取得了明显疗效。但在临床使用中,EG-FR-TKI敏感病人在用药6~8月后部分出现了疾病进展即获得性耐药,获得性耐药的发生使小分子     

EGFR TKIs在非小细胞肺癌中的耐药机制及治疗进展

吉非替尼和厄洛替尼是表皮生长因子受体(epidermal growth factor receptor,EGFR)酪氨酸激酶抑制剂(tyrosine kinase inhibitors,TKIs),广泛用于非小细胞肺癌的治疗。但随着应用的深入,耐药问题开始凸显。过去几年,针对继发性耐药和原发性耐药的深入研究,发现EGFR二次突变,MET基因扩增, K-ras基因突变等是EGFR TKIs耐药的主要原因。本文就EGFR-TKIs原发耐药与继发耐药的机制,以及克服此类耐药的新型药物及其临床试验数据作一综述。     

非小细胞肺癌脑转移厄洛替尼结合全脑放疗治疗的理论基础和研究进展

非小细胞肺癌（NSCLC）脑转移患者预后极差,全脑放疗（WBRT）不能同时控制颅外病灶。酪氨酸激酶抑制剂（TKI）对肺腺癌脑转移瘤患者的研究结果是令人鼓舞的,表皮生长因子受体（EGFR）突变状态与疗效相关。厄洛替尼配合全脑放疗治疗肺癌脑转移患者增敏的理论基础存在。目前,小型临床试验资料显示厄洛替尼联合全脑放疗较单纯厄洛替尼疗效更佳,且不良反应可耐受。     

三种EGFR-TKI药物治疗晚期肺癌疗效及预后因素的回顾性研究

目的:探讨厄洛替尼、吉非替尼、埃克替尼治疗晚期非小细胞肺癌的疗效及安全性。方法:收集从2015年12月至2017年9月被确诊为转移性非小细胞肺癌的46位患者，分析了患者接受三种TKI药物治疗后基线特征、生存期及安全性。结果:研究结果表明，三组患者接受TKI药物治疗后总PFS为9.2个月，厄洛替尼组患者平均PFS为10.8个月，接受吉非替尼及埃克替尼治疗的患者，其PFS分别为7.8 个月和6.7个月。不同EGFR突变类型的肺癌患者，其PFS相似，约9个月。接受TKI治疗前CEA及CYFRA211阳性的患者，其PFS分别为8.0个月和8.5个月。接受TKI治疗前CEA及CYFRA211阴性的患者，其PFS均约为10.8个月。研究中发现，常见的治疗相关不良反应包括乏力、皮疹及腹泻。而肝功能不全、骨髓抑制、浮肿、发热、甲沟炎和疼痛发生率较低。结论:三种TKI药物在具有EGFR敏感突变的晚期转移性肺癌患者中显示了较好的抗肿瘤作用、可耐受药物的毒性。     

尼洛替尼一线治疗慢性髓系白血病的进展

慢性髓系白血病(CML)是一类骨髓增殖性肿瘤,其发病机制与BCR/ABL融合基因相关。酪氨酸激酶抑制剂(TKI)可显著改善CML患者的生存及预后。尼洛替尼一线治疗CML患者疗效显著、治疗反应快、缓解程度深并且安全性高。在获得持续深层分子反应后,实现停止尼洛替尼用药并达到无治疗缓解是CML治疗的新目标。此外,由于疾病耐药及突变的产生,尼洛替尼治疗失败后如何开始新的治疗值得进一步研究。     

Acquired Resistance to Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors in Non–Small-Cell Lung Cancers Dependent on the Epidermal Growth Factor Receptor Pathway

Most advanced Non–Small-cell lung cancers (NSCLCs) with activating epidermal growth factor receptor (EGFR) mutations (exon 19 deletions or L858R) initially respond to the EGFR tyrosine kinase inhibitors (TKIs) gefitinib and erlotinib. However, over time (median of 6–12 months), most tumors develop acquired resistance to EGFR TKIs. Intense research in these NSCLCs has identified two major mechanisms of resistance to gefitinib/erlotinib: secondary resistance mutations and “oncogene kinase switch" systems. The secondary T790M mutation occurs in 50% of EGFR-mutated patients with TKI resistance, and in vitro, this mutation negates the hypersensitivity of activating EGFR mutations. Sensitive detection methods have identified a proportion of TKI-naive tumors that carry T790M, and these resistant clones may be selected after exposure to gefitinib or erlotinib. Other secondary resistance mutations (D761Y, L747S, T854A) seem to be rare. The amplification of the MET oncogene is present in 20% of TKI-resistant tumors; however, in half of the cases with this “oncogene kinase switch" mechanism the T790M is coexistent. It is possible that other kinases (such as insulin-like growth factor-1 receptor [IGF-1R]) might also be selected to bypass EGFR pathways in resistant tumors. The growing preclinical data in EGFR-mutated NSCLCs with acquired resistance to gefitinib or erlotinib has spawned the initiation or conception of clinical trials testing novel EGFR inhibitors that in vitro inhibit T790M (neratinib, XL647, BIBW 2992, and PF-00299804), MET, or IGF-1R inhibitors in combination with EGFR TKIs, and heat shock protein 90 inhibitors. Ongoing preclinical and clinical research in EGFR-mutated NSCLC has the potential to significantly improve the outcomes of patients with these somatic mutations.     

Challenges of detecting EGFR T790M in gefitinib/erlotinib-resistant tumours

For patients with advanced non-small cell lung cancer (NSCLC), the introduction of the epi- dermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs), gefitinib and erlotinib, into clinical practice was promising. Treatment with either of these agents is associated with an objective response in 10-20% of patients. Subsequent studies have shown that patients responsive to gefitinib/erlotinib have tumours containing somatic activating mutations in the EGFR gene. Although impressive clinical and radiological responses have been observed in these patients, tumour progression occurs after the prolonged administration of gefitinib/erlotinib as acquired resistance develops. In order to combat acquired resistance, research has been largely focused on determining the factors underlying it. Two resistance mechanisms have so far been identified: a secondary mutation in the EGFR gene, T790M, and amplification of the MET proto-oncogene. This review will centre on T790M, which is thought to cause steric hindrance and impair the binding of gefitinib/erlotinib. A novel class of irreversible TKIs currently under development may retain activity against some common resistance mechanisms, including T790M. The next challenge is to identify accurately the subgroup of patients with NSCLC whose tumours harbour EGFR T790M. To this end, post-treatment tumour specimens will be needed to establish molecular profiles for each patient. In addition, novel, highly sensitive technology will be required to detect these mutations. This is because allelic dilution, whereby the EGFR gene is amplified but only a few copies of the T790M allele are needed to confer resistance, may obscure results of conventional sequencing methods. The importance of identifying patients who harbour T790M cannot be overstated; the development of irreversible TKIs will have profound implications for their treatment. In this way, treatment strategies in NSCLC are becoming increasingly tailored to the individual, and may set an example for other areas of oncology.     

厄洛替尼与西妥昔单抗联合应用治疗吉非替尼耐药NSCLC的疗效

本研究通过EGFR-TKI和EGFR单克隆抗体联合应用探讨治疗EGFR突变阴性和EGFR T790M突变继发性耐药的NSCLC的疗效。方法:应用EGFR突变阴性和EGFR T790M突变继发性耐药的NSCLL细胞原代培养及药敏技术检验EGFR-TKI和EGFR单克隆抗体联合应用的疗效。结果:检测厄洛替尼和西妥昔单抗联合处理对于15例EGFR突变阴性和8例T790M突变阳性的继发性耐药的NSCLC患者原代细胞的影响,应用浓度分别为50 μg/mL西妥昔单抗和1 μM厄洛替尼作用于EGFR突变阴性的NSCLC患者原代细胞,结果显示这三组间T/C值无显著性差异（P>0.05）,对于T790M突变阳性的继发性耐药的NSCLC原代细胞这三组间T/C值有显著性差异（P<0.05）,联合用药组疗效明显高于单药组。结论:进一步验证了厄洛替尼和西妥昔单抗联合应用对于EGFR突变阴性的NSCLC患者无效,但对于T790M突变阳性的继发性耐药的NSCLC患者有效。      

Bronchial and peripheral murine lung carcinomas induced by T790M-L858R mutant EGFR respond to HKI-272 and rapamycin combination therapy

The EGFR T790M mutation has been identified in tumors from lung cancer patients that eventually develop resistance to erlotinib. In this study, we generated a mouse model with doxycycline-inducible expression of a mutant EGFR containing both L858R, an erlotinib-sensitizing mutation, and the T790M resistance mutation (EGFR TL). Expression of EGFR TL led to development of peripheral adenocarcinomas with bronchioloalveolar features in alveoli as well as papillary adenocarcinomas in bronchioles. Treatment with an irreversible EGFR tyrosine kinase inhibitor (TKI), HKI-272, shrunk only peripheral tumors but not bronchial tumors. However, the combination of HKI-272 and rapamycin resulted in significant regression of both types of lung tumors. This combination therapy may potentially benefit lung cancer patients with the EGFR T790M mutation.     

Poor response to erlotinib in patients with tumors containing baseline EGFR T790M mutations found by routine clinical molecular testing

BackgroundEGFR T790M is the most common mutation associated with acquired resistance to EGFR tyrosine kinase inhibitors (TKIs). Baseline EGFR T790M mutations in EGFR TKI-naïve patients have been reported, but the frequency and their association with response to EGFR TKIs remain unclear.Patients and methodsThe frequency of baseline EGFR T790M as detected by routine molecular genotyping was determined by reviewing clinical results obtained at our institution from 2009 to 2013. We also collected outcome data for treatment with EGFR TKIs.ResultsTo define the incidence of EGFR T790M, we reviewed 2774 sequentially tested patients with lung cancer who underwent molecular testing using a mass spectrometry-based assay, and 11 (0.5%) had baseline EGFR T790M. Compiling results from several molecular techniques, we observed EGFR T790M in tumors from 20 patients who had not previously been treated with an EGFR TKI. In all cases, EGFR T790M occurred concurrently with another EGFR mutation, L858R (80%, 16/20), or exon 19 deletion (20%, 4/20). Two percent of all pre-treatment EGFR-mutant lung cancers harbored an EGFR T790M mutation. Thirteen patients received erlotinib monotherapy as treatment for metastatic disease. The response rate was 8% (1/13, 95% confidence interval 0%–35%). For the patients who received erlotinib, the median progression-free survival was 2 months and the median overall survival was 16 months.ConclusionsDe novo EGFR T790M mutations are rare (<1%) when identified by standard sensitivity methods. TKI therapy for patients with baseline EGFR T790M detected by standard molecular analysis has limited benefit.     

Incidence of T790M in Patients With NSCLC Progressed to Gefitinib,Erlotinib, and Afatinib: A Study on Circulating Cell-free DNA

BackgroundInsights into the mechanism of resistance to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) could provide important information for further patient management, including the choice of second-line treatment. The EGFR T790M mutation is the most common mechanism of resistance to first- and second-generation EGFR TKIs. Owing to its biologic relevance in the response of non–small-cell lung cancer (NSCLC) to the selective pressure of treatment, the present study investigated whether the occurrence of T790M at progression differed among patients receiving gefitinib, erlotinib, or afatinib.Patients and MethodsThe present retrospective study included patients with NSCLC with an EGFR activating mutation, who had received gefitinib, erlotinib, or afatinib as first-line treatment. Plasma samples for the analysis of cell-free DNA were taken at disease progression and analyzed using a digital droplet polymerase chain reaction EGFR mutation assay.ResultsA total of 83 patients were enrolled; 42 had received gefitinib or erlotinib and 41afatinib. The patient characteristics were comparable across the 2 groups. The median time to progression (TTP) was 14.4 months for the gefitinib and erlotinib group and 10.2 months for the afatinib group (P = .09). Of the 83 patients, 47 (56.6%) were positive for the T790M in plasma. A greater incidence of T790M was observed in patients with progression during gefitinib or erlotinib therapy compared with patients treated with afatinib (33 [79%] vs. 14 [34%], respectively; odds ratio, 7.1; 95% confidence interval, 2.7-18.5; P = .0001).ConclusionsAlthough gefitinib, erlotinib, and afatinib showed a comparable TTP in patients receiving first-line therapy, the incidence of T790M differed among them, as demonstrated by the present study, which could have implications for the choice of second-line treatment.     

The role of irreversible HER family inhibition in the treatment of patients with non-small cell lung cancer

Small-molecule tyrosine kinase inhibitors (TKIs) of the human epidermal growth factor receptor (HER) include the reversible epidermal growth factor receptor (EGFR/HER-1) inhibitors gefitinib and erlotinib. EGFR TKIs have demonstrated activity in the treatment of patients with non-small cell lung cancer (NSCLC) harboring activating EGFR mutations; however, multiple mechanisms of resistance limit the benefit of these drugs. Although resistance to EGFR TKIs can be intrinsic and correlated with molecular lesions such as in Kirsten rat sarcoma viral oncogene homolog (KRAS; generally observed in a wild-type EGFR background), acquired resistance to EGFR TKIs can evolve in the setting of activating EGFR mutations, such as in the case of EGFR T790M mutations. Several irreversible inhibitors that target multiple members of the HER family simultaneously are currently in clinical development for NSCLC and may have a role in the treatment of TKI-sensitive and TKI-resistant disease. These include PF00299804, an inhibitor of EGFR/HER-1, HER-2, and HER-4, and afatinib (BIBW 2992), an inhibitor of EGFR/HER-1, HER-2, and HER-4. Results of large, randomized trials of these agents may help to determine their potential for the treatment of NSCLC.     

Novel D761Y and common secondary T790M mutations in epidermal growth factor receptor-mutant lung adenocarcinomas with acquired resistance to kinase inhibitors.

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.     

Schedule-dependent antitumor activity of the combination with erlotinib and docetaxel in human non-small cell lung cancer cells with EGFR mutation, KRAS mutation or both wild-type EGFR and KRAS

Erlotinib is used as a standard treatment for recurrent advanced non-small cell lung cancer (NSCLC). Epidermal growth factor receptor (EGFR) mutations in NSCLC have been shown to be a predictive factor of erlotinib, although the relationship between K-ras oncogene (KRAS) mutations and erlotinib resistance is controversial. Recently, in vitro sequence-dependent interactions of erlotinib and docetaxel have been studied on as a novel therapeutic approach against NSCLC. The purpose of the present study was to determine the optimum novel regimen of erlotinib and docetaxel against NSCLC cells which have EGFR mutation (HCC827 cells), KRAS mutation (A549 cells) or both wild-type (NCI-H292 cells). First, we analyzed the effects of in vitro combination for cell proliferation-inhibition using a combination index. In all cell lines, docetaxel followed by erlotinib treatment showed nearly additive effects. On the other hand, erlotinib followed by docetaxel treatment showed remarkable antagonistic interactions. Second, we examined the effect of combinations on the in vitro apoptosis induction. Erlotinib followed by docetaxel treatment reduced apoptosis induction compared with docetaxel alone; in contrast, docetaxel followed by erlotinib treatment had no inhibitory effects on docetaxel-induced apoptosis in any of the cell lines. Finally, an in vivo tumor growth inhibition test was performed using xenograft models. Docetaxel followed by erlotinib administration resulted in significant tumor growth inhibition compared with erlotinib or docetaxel monotherapy in all models. In conclusion, we demonstrated that docetaxel followed by erlotinib therapy was a potentially optimum regimen against NSCLC regardless of the mutation status of EGFR and KRAS.     

Mechanisms of acquired resistance to epidermal growth factor receptor tyrosine kinase inhibitors in non-small cell lung cancer.

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors gefitinib and erlotinib are effective therapies for non-small cell lung cancer patients whose tumors harbor somatic mutations in EGFR. All patients, however, ultimately develop resistance to these agents. Thus, there is a great need to understand how patients become resistant to develop effective therapies for these cancers. Studies over the last few years have identified two different EGFR tyrosine kinase inhibitor resistance mechanisms, a secondary mutation in EGFR, EGFR 790M, and amplification of the MET oncogene. These findings have led to clinical trials using newly designed targeted therapies that can overcome these resistance mechanisms and have shown promise in laboratory studies. Ongoing research efforts will likely continue to identify additional resistance mechanisms, and these findings will hopefully translate into effective therapies for non-small cell lung cancer patients.