EGFR-tyrosine kinase inhibitor treatment beyond progression in long-term Caucasian responders to erlotinib in advanced non-small cell lung cancer: a case-control study of overall survival

Treatment beyond progression in non-small cell lung cancer: A systematic review and meta-analysis

OBJECTIVES

Treatment beyond progression (TBP) is defined as treatment continuing in spite of disease progression, according to the Response Evaluation Criteria In Solid Tumors. We performed a systematic review and meta-analysis to provide evidence for the effects of TBP on lung cancer survival.

MATERIALS AND METHODS

This study has been conducted following the PRISMA guidelines. A systematic review of PubMed, MEDLINE, Embase, and Cochrane Collaboration Central Register of Controlled Clinical Trials from the inception of each database to December 2021 was conducted. Two authors independently reviewed articles for inclusion and extract data from all the retrieved articles. Random-effects meta-analysis was performed using Comprehensive Meta-Analysis software, version 3 (Biostat, Englewood, NJ, USA). Hazard ratios (HRs) with the corresponding 95% confidence intervals (CI) were used for survival outcomes.

RESULTS

We identified five (15.6%) prospective randomized trials and twenty-seven (84.4%) retrospective observational studies of a total of 9,631 patients for the meta-analysis. 3,941 patients (40.9%) were in a TBP group and 5,690 patients (59.1%) were in a non-TBP group. There is a statistically significant advantage for patients who received TBP compared with those who did not in post progression progression-free survival (ppPFS), post progression overall survival (ppOS), and overall survival (OS) from initiation of drugs (ppPFS: HR, 0.746; 95% CI, 0.644-0.865; P<0.001; ppOS: HR, 0.689; 95% CI, 0.596-0.797; P<0.001; OS from initiation of drugs: HR, 0.515; 95% CI, 0.387-0.685; P<0.001).

CONCLUSION

This study provides further evidence in support of TBP for NSCLC, however, these results require cautious interpretation. Large, randomized, controlled trials investigating the efficacy of TBP in lung cancer treatment are warranted.

SYSTEMIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/PROSPERO/ identifier CRD42021285147.

Uncommon EGFR mutations in non-small-cell lung cancer: A systematic literature review of prevalence and clinical outcomes

Mutations in exons 18-21 of the epidermal growth factor receptor gene (EGFR) can confer sensitivity to EGFR-tyrosine kinase inhibitors (EGFR-TKIs) in patients with non-small-cell lung cancer (NSCLC). Deletions in exon 19 or the exon 21 L858R substitution comprise approximately 85% of mutations, but comparatively few data are available on the remaining "uncommon" mutations. We conducted a systematic literature review to identify evidence on uncommon EGFR mutations in locally advanced/metastatic NSCLC (PROSPERO registration number: CRD42019126583). Electronic screening and congress searches identified studies published in 2012-2020 including patients with locally advanced/metastatic NSCLC and uncommon EGFR mutations (excluding T790M). We assessed the prevalence of uncommon mutations (in studies using direct sequencing of exons 18-21), and compared response to treatment and progression-free survival (PFS) in patients with common versus uncommon mutations and in those with exon 20 mutations versus other uncommon mutations. We identified 64 relevant studies. Uncommon mutations constituted 1.0-18.2% of all EGFR mutations, across 10 studies. The most frequently reported uncommon mutations were G719X (0.9-4.8% of all EGFR mutations), exon 20 insertions (Ex20ins; 0.8-4.2%), L861X (0.5-3.5%), and S768I (0.5-2.5%). Patients with common mutations typically experienced better treatment response and longer PFS on EGFR-TKIs than patients with uncommon mutations; Ex20ins mutations were associated with less favourable outcomes than other uncommon mutations. This review shows that uncommon mutations may comprise a clinically significant proportion of the EGFR mutations occurring in NSCLC, and highlights disparities in EGFR-TKI sensitivity between different uncommon mutations.

Management of oligometastatic and oligoprogressive renal cell carcinoma: state of the art and future directions

INTRODUCTION

The aim of this paper was to perform a narrative review of the literature on the available approaches in the treatment of two emerging subpopulations of metastatic renal cell carcinoma (mRCC) patients: the oligometastatic disease (less than 5 metastasis) and the oligoprogressive disease, defined as worsening in maximum 3-5 sites while all other tumor sites are controlled by systemic therapy.

AREAS COVERED

We explore all possible approaches in these settings of patients: the role of local therapies, considering both surgical metastasectomy and/or ablative techniques, the efficacy of systemic therapies and the rationale behind active surveillance. We also discuss ongoing clinical trials in these settings.

EXPERT OPINION

Two different strategies are emerging as the most promising for the approach to the oligometastatic/oligoprogressive mRCC patient: (1) the use of immunocheckpoint inhibitors following metastasectomy; (2) the use of stereotactic radiotherapy alone or combined with immunotherapy for oligometastatic disease. The lack of validated biomarkers of response in these mRCC patient subpopulations is opening the way to the employment of novel technologies. Among them, the use of artificial intelligence seems to be the candidate to contribute to precision oncology in patients with mRCC.

Survival outcome of tyrosine kinase inhibitors beyond progression in association to radiotherapy in oligoprogressive EGFR-mutant non-small-cell lung cancer

Aim: The association of tyrosine kinase inhibitors (TKIs) and local radiotherapy in EGFR-mutated non-small-cell lung cancer patients experiencing disease progression under TKIs could be a valid an option. Patients & methods: We included 131 patients experiencing disease progression during first-line TKI. In group A, patients received TKI beyond progression and site(s) of progression were irradiated; in group B, patients remained on TKI alone beyond progression; and group C stopped TKI at first disease progression. Results: Median overall survival resulted longer in group A versus B and C (p < 0.0001). Group A had a trend toward a longer second progression-free survival (measured from the time of first progression until second progression) versus group B (p = 0.06). Conclusion: TKI beyond progression in association with local ablative treatment is a valid treatment option in oligoprogressive patients.

The Management of Oligoprogression in the Landscape of New Therapies for Metastatic Melanoma

Background: A limited degree of progression after a response to treatment is labelled as oligoprogression and is a hot topic of metastatic melanoma (MM) management. Rogue progressive metastases could benefit from local treatment, which could allow the continuation of ongoing systemic therapy, also known as treatment beyond progression (TBP). Methods: We retrospectively reviewed 214 selected MM patients who developed oligoprogression during treatment with v-Raf murine sarcoma viral oncogene homolog B (BRAF)/mitogen-activated-extracellular signal-regulated kinase (MEK) or programmed cell death protein 1 (PD-1) inhibitors and received a local treatment continuing TBP. We performed univariate and multivariable analyses to assess the association between therapy outcomes and a series of clinical and biological features. Results: We identified 27 (10%) oligoprogressed patients treated locally with surgery (14), radiosurgery (11), and electrochemotherapy (2). TBP included PD-1 inhibitors (13) and BRAF/MEK inhibitors (14). The median progression-free survival post oligoprogression (PFSPO) was 14 months (5-19 95% confidence interval (C.I.)). In the univariate analysis, a significantly longer PFSPO was associated with complete response (CR), Eastern Cooperative Oncology Group (ECOG) performance status (PS) of 0, neutrophils/lymphocytes ratio (N/L) <2, and progression-free survival (PFS) at oligoprogression >11 months. Nevertheless, in the multivariable analysis, only CR and N/L <2 were found to be associated with longer PFSPO. Conclusions: In selected patients, local treatments contribute to controlling oligoprogression for a long time, allowing the continuation of systemic treatment and prolongation of overall survival (OS). Increasing biological and clinical knowledge is improving the accuracy in identifying patients to apply for local ablative therapies.

Epidermal growth factor receptor tyrosine kinase inhibitors for the treatment of non-small cell lung cancer

Introduction: Epidermal growth factor receptor (EGFR) mutations are well-described drivers of non-small cell lung cancer (NSCLC) and EGFR tyrosine kinase inhibitors (TKIs) have become key components of the NSCLC front-line treatment landscape. Tumors inevitably develop resistance to these agents, and development efforts continue to focus on identifying mechanisms of resistance and drugs to target these mechanisms. Areas covered: With several EGFR TKIs approved for use in the first-line or in later-line settings, an understanding of the efficacy and safety of these inhibitors in various populations is warranted. Furthermore, given the frequent emergence of drug resistance in NSCLC, examination of tumor tissue throughout the disease course provides the opportunity to select treatments based on the tumor's mutation profile. Here, we discuss: key efficacy and safety findings for approved and investigational EGFR TKIs; known mechanisms of resistance, particularly the T790M acquired EGFR mutation; and recent advances in EGFR mutational testing that may facilitate less invasive tissue testing and guide treatment selection. Expert commentary: The expanding armamentarium of EGFR TKIs, improvements in the understanding of resistance mechanisms and technological developments in the molecular analysis of tumors may help render EGFR mutation-positive NSCLC a chronic disease in many patients by facilitating optimal sequential therapy.

Clinical Modality of Resistance and Subsequent Management of Patients with Advanced Non-small Cell Lung Cancer Failing Treatment with Osimertinib

BACKGROUND

The third-generation epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor (TKI) osimertinib has become the standard treatment for patients with pretreated EGFR-mutated non-small cell lung cancer (NSCLC) who acquire the T790M resistance mutation. However, no standard treatment after osimertinib failure has been established.

OBJECTIVE

This study was undertaken to explore the clinical resistance modality upon failure of osimertinib therapy and to assess post-progression treatments in a real-world setting.

PATIENTS AND METHODS

Medical data were retrospectively collected in our cancer center of patients with advanced NSCLC treated between 1 March 2017 and 1 July 2018, and who developed resistance to osimertinib.

RESULTS

A total of 65 patients were analyzed. Clinical resistance modality varied among patients: 15 (23.1%) with local progression, 29 (44.6%) with gradual progression, and 21 (32.3%) with dramatic progression. Most patients experienced intrathoracic progression only (40/65, 61.5%), while ten (15.4%) cases presented intracranial failure only. Upon progressive disease, 20 patients (30.8%) received subsequent chemotherapy, and showed a trend for longer median overall survival (OS) than in those receiving a non-chemotherapy regimen (25.0 vs. 11.8 months, p = 0.106). Thirty-nine patients (60.0%) continued osimertinib beyond progression with a median post-progression treatment duration of 4.1 months. No significant difference in median OS was seen between patients who continued osimertinib and those who discontinued osimertinib (18.9 vs. 15.1 months, p = 0.802). In subgroup analyses, OS was improved in patients who experienced dramatic progression and were treated with chemotherapy, but data were immature for patients with local or gradual progression.

CONCLUSIONS

Chemotherapy could be an effective option after osimertinib failure in unselected patients.

First-line afatinib for advanced EGFRm+ NSCLC: Analysis of long-term responders in the LUX-Lung 3, 6, and 7 trials

OBJECTIVES

In patients with advanced epidermal growth factor receptor mutation-positive (EGFRm+) non-small cell lung cancer (NSCLC), first-line afatinib significantly improved progression-free survival (PFS) and objective response vs. platinum-doublet chemotherapy in the phase III LUX-Lung 3 and LUX-Lung 6 trials, and significantly improved PFS, time to treatment failure and objective response vs. gefitinib in the phase IIb LUX-Lung 7 trial. We report post-hoc analyses of efficacy, safety and patient-reported outcomes (PROs) in afatinib long-term responders (LTRs) in these trials.

METHODS

Treatment-naïve patients with stage IIIB/IV EGFRm + NSCLC randomized to afatinib in LUX-Lung 3/LUX-Lung 6/LUX-Lung 7 were included in the analysis. Patients treated with afatinib for ≥ 3 years were defined as LTRs.

RESULTS

In LUX-Lung 3, LUX-Lung 6, and LUX-Lung 7, 24/229 (10%), 23/239 (10%) and 19/160 (12%) afatinib-treated patients were LTRs. Baseline characteristics were similar to the study populations, except for the proportions of women (LUX-Lung 3/LUX-Lung 6 only; 92/78% vs. 64% overall) and Del19-positive patients (63-79% vs. 49-58% overall). Median treatment duration among LTRs was 50, 56 and 42 months, and median PFS was 49.5, 55.5, and 42.2 months in LUX-Lung 3/LUX-Lung 6/LUX-Lung 7, respectively. Median overall survival could not be estimated. Frequency of afatinib dose reduction was consistent with the LUX-Lung 3/LUX-Lung 6/LUX-Lung 7 overall populations. PROs were stable in LTRs, with slight improvements after 3 years of afatinib treatment vs. baseline scores.

CONCLUSIONS

In the LUX-Lung 3/LUX-Lung 6/LUX-Lung 7 trials, 10-12% of afatinib-treated patients were LTRs. Long-term afatinib treatment was independent of tolerability-guided dose adjustment and had no detrimental impact on safety or PROs.

Oncogenic driver mutations, treatment, and EGFR-TKI resistance in a Caucasian population with non-small cell lung cancer: survival in clinical practice

Introduction

Oncogenic driver mutations activating EGFR, ALK, or BRAF in NSCLC predict sensitivity to specific tyrosine-kinase inhibitors (TKIs). We provide data on prevalence, treatment and survival of driver-mutation positive NSCLC in a predominantly Caucasian population in routine clinical practice.

Patients and Methods

NSCLC patients diagnosed from 2006-2015 with an EGFR-test result were included (n=265). Testing for EGFR, ALK, or BRAF was performed if specific TKI therapy was considered. Case-control analyses of overall survival (OS) comparing driver-mutation positive and negative patients were performed.

Results

44 sensitizing EGFR mutations (17%), 8 ALK translocations (7%, n=111) and 3 BRAF mutations (8%, n=39) were detected in adenocarcinoma or adenosquamous carcinoma. We did not find mutations in tumors without an adenocarcinoma-component. More than 90% of inoperable driver-mutation positive patients received TKI-therapy. Case-control analysis revealed improved OS of driver-mutation positive patients (39.6 vs. 19.4 months, HR 0.51). OS was improved in stage IV patients but not in stage I-III patients.

OS of EGFR-TKI treated patients was similar for 1^st and 2^nd-line EGFR-TKI treatment. Patients not treated with EGFR-TKI had no benefit in OS. Re-biopsies obtained at progression revealed an EGFR-T790M mutation in 73% (n=11). These patients responded to the 3^rd-generation EGFR-TKI osimertinib.

Discussion

Testing guided by predictive clinical parameters resulted in twice as high rates of mutation-positive patients than expected, and TKI treatment resulted in a strong long-term OS advantage.

Conclusion

Testing for driver mutations is feasible in routine clinical practice, and identifies patients who benefit from TKI-therapy. OS compares favorably with OS in clinical studies.

Continuous EGFR tyrosine kinase inhibitor treatment with or without chemotherapy beyond gradual progression in non-small cell lung cancer patients

Background

Several clinical studies have demonstrated that continuous administration of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) could provide additional survival benefit for advanced non-small cell lung cancer (NSCLC) patients who had benefited from prior EGFR TKI therapy. However, whether EGFR TKI combined with chemotherapy could further prolong survival in patients with gradual progression is still unclear. The present study was conducted to evaluate the clinical outcome of continuous EGFR TKI treatment in combination with chemotherapy (combination group) versus continuous EGFR TKI treatment only (monotherapy group) in such a clinical setting.

Methods

We designed a cohort study to collect all chart data of NSCLC patients treated with EGFR TKI in our institution from February 2012 to December 2015 retrospectively and followed up the clinical outcome of EGFR TKI monotherapy or therapy in combination with chemotherapy until April 2017 prospectively. All eligible patients had to meet the criteria of gradual progression. The time interval of progression-free survival 1 (PFS1, gradual progression or death) to PFS2 (off-EGFR TKI progression), and overall survival (OS) between the above 2 groups were used in survival analysis.

Results

In all, 50 patients were included in our study. Patients’ baseline characteristics were well balanced. Exon 19 deletion mutations and L858R point mutations were detected in 16 and 8 patients, respectively. Twenty, 22, and 8 patients were treated with EGFR TKI in the first, second, and third line setting, respectively. The time interval from PFS1 to PFS2 was 92 and 37 days (monotherapy vs combination), respectively (hazard ratio [HR] =1.16, 95% confidence interval [CI]: 0.61–2.21, P=0.652). The median OS in the monotherapy group and combination group was 696 and 799 days, respectively (HR =0.74, 95% CI: 0.33–1.71, P=0.501). There were no statistical differences between the 2 groups in terms of the time interval from PFS1 to PFS2 and OS.

Conclusion

Our results suggested that compared with EGFR TKI monotherapy, its combination with chemotherapy beyond gradual progression may not confer a significant survival benefit to NSCLC patients. Further prospective studies are warranted to reinforce the results of the study.

Optimal management of EGFR-mutant non-small cell lung cancer with disease progression on first-line tyrosine kinase inhibitor therapy

The first-generation epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs), gefitinib and erlotinib, and the second-generation EGFR-TKI, afatinib, have all been approved as standard first-line treatments for advanced EGFR-mutant non-small cell lung cancer (NSCLC) based on superior progression-free survival results compared to platinum doublet chemotherapy regimens. Acquired resistance to an EGFR-TKI inevitably develops after a period of effective drug treatment. After tumor progression, many combination therapy regimens that include an EGFR-TKI, or EGFR-TKI monotherapy, have been tested in prospective trials with the aim of extending survival. Third-generation EGFR-TKIs such as osimertinib have been developed with the aim of overcoming the effects of EGFR T790M resistance mutation, which occurs in half of the patients with disease progression on EGFR-TKI therapy. Osimertinib has become the standard treatment in patients for whom tumor re-biopsy reveals an acquired EGFR T790M mutation following EGFR-TKI therapy. Other third-generation EGFR-TKIs, such as olmutinib, EGF816, and ASP8273, are still in the trial phase.

[Clinical Analysis of Icotinib on Beneficiary of Advanced Non-small Cell Lung Cancer with EGFR Common Mutation]

背景与目的

靶向治疗已经成为晚期非小细胞肺癌（non-small cell lung cancer, NSCLC）治疗中不可或缺的重要手段，表皮生长因子受体（epithelial growth factor receptor, EGFR）的酪氨酸激酶抑制剂（tyrosine kinase inhibitor, TKI）可显著延长晚期携带EGFR基因突变肺癌患者生存期。埃克替尼是我国第一个拥有自主知识产权的EGFR-TKI。本研究旨在探讨埃克替尼治疗EGFR敏感突变的晚期NSCLC获益患者的临床特点，对获益患者[无进展生存时间（progression-free survival, PFS）≥6个月]进行回顾性资料收集并分析相关影响因素。

方法

收集2011年9月1日-2015年9月30日浙江省肿瘤医院经埃克替尼片治疗的231例EGFR敏感突变的晚期NSCLC获益患者的生存情况。

结果

经埃克替尼治疗后，一线治疗组1年获益率达67.9%，二线及以上组为53.6%，具有统计学意义（P=0.027）；一线治疗组2年获益率对比二线及以上组亦有统计学差异（18.7%和9.3%，P=0.047）。一线患者和二线及以上患者的中位PFS分别为16.7个月和12.4个月，且差异具有统计学意义（P=0.006）。其中有无脑转移（P=0.010）、埃克替尼治疗时机（P=0.001）、美国东部肿瘤协作组（Eastern Cooperative Oncology Group, ECOG）评分（P=0.001）为影响预后的主要因素。主要不良反应为皮疹51例（22.1%），腹泻27例（11.7%）。

结论

埃克替尼是EGFR基因敏感突变的晚期NSCLC患者有效的治疗方案，其优势人群除无脑转移者及ECOG评分好的患者外，一线治疗患者疗效明显优于二线及以上者。敏感突变患者采用埃克替尼可得到较好的临床获益，并具有较好的耐受性。

Continuing EGFR inhibition beyond progression in advanced non-small cell lung cancer

The majority of patients with epidermal growth factor receptor (EGFR) mutant non-small cell lung cancer (NSCLC) respond to first-line EGFR tyrosine kinase inhibitors (TKIs), but nearly all inevitably acquire resistance and develop disease progression. Conventional practice would be to switch treatments to second-line therapy. However, continuing TKIs beyond progression is becoming increasingly commonplace in patients with indolent, small volume asymptomatic growth, who may potentially continue to derive ongoing clinical benefit and to avoid a 'withdrawal tumour flare'. Nevertheless, there are limitations to our current criteria for assessing disease response, which are based on radiological assessments without considering symptomatic benefit, or the complex molecular and clinical heterogeneity of tumour growth and drug response patterns. In this article, we review the rationale for continuing EGFR inhibitors in patients with EGFR mutant NSCLC beyond disease progression and discuss strategies that have been pursued in the context of molecularly and clinically heterogeneous populations of tumour growth depending on the different clinical scenarios encountered. We discuss the management of systemic disease progression, including continuing EGFR TKIs alone, introducing a drug holiday, or combining TKIs with chemotherapy or other molecularly targeted agents. We also focus on approaches in managing patients with indolent, small volume asymptomatic growth (non-CNS oligometastatic disease progression) and those with oligometastatic EGFR mutant NSCLC with involvement of the central nervous system. We envision future precision medicine strategies through the use of next generation sequencing strategies of serial tumour rebiopsies and circulating plasma DNA to individualise the management for such patients during disease progression.

Continuation of epidermal growth factor receptor tyrosine kinase inhibitor treatment prolongs disease control in non-small-cell lung cancers with acquired resistance to EGFR tyrosine kinase inhibitors

Objectives

Patients with non-small-cell lung cancer (NSCLC) develop acquired resistance to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR TKIs) after tumor regression. No approved targeted therapies are currently available after initial EGFR TKI treatment. This study investigated the efficacy of continuing EGFR TKI therapy with local treatments for patients with NSCLC and local progression or minimal/slow progression on TKI therapy.

Materials and Methods

Fifty-five patients with NSCLC treated with EGFR TKIs and developed acquired resistance to the drug were included. Initial response to target therapy, median progression free survival (PFS1), progression pattern, and first progression site were assessed. Median progression free survival to physician assessment progression (PFS2) and difference between PFS1 and PFS2 (PFS difference) were also recorded.

Results and Conclusion

PFS1 was 11.2 months, PFS2 was 20.3 months, and PFS difference was 8.3 months. Nineteen patients (34.5%) who manifested progression received local therapy, and 16 (28.6%) underwent rebiopsy after progression with six positive EGFR T790M mutations detected. Cox proportional hazards regression model showed that only the first line of treatment was significantly correlated with PFS difference. NSCLC patients with acquired resistance to EGFR TKIs could benefit from the same TKI therapy through months to years of disease control.

Treatment and prognosis after progression in long-term responders to EGFR-tyrosine kinase inhibitor in advanced non-small cell lung cancer

INTRODUCTION

The aim of this study was to investigate the treatment and prognosis of advanced non-small cell lung cancer (NSCLC) patients after failure of long-term treatment with epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI).

MATERIAL AND METHODS

We retrospectively analyzed all NSCLC patients with EGFR-TKI (gefitinib or erlotinib) treatment at our institution between 2011 and 2013 who progressed after at least stable disease on erlotinib or gefitinib for more than 6 months. Survival curves were plotted using the Kaplan-Meier method. The Cox proportional hazard model was used for multivariate analysis.

RESULTS

In total, 521 patients were administered EGFR-TKI. Of these, 298 patients received EGFR-TKI with progression-free survival less than 6 months (group A), and the other 223 patients more than 6 months (group B). There was a significant difference in overall survival (OS) between group A and group B (7.2 months vs. 5.0 months, p < 0.0001). The median OS for group B patients was 5.0 months. Among the 223 patients in group B, 38 patients received chemotherapy with continued EGFR-TKI after failure of prior gefitinib or erlotinib treatment, 92 with chemotherapy alone and 93 with best supportive care. Patients who continued gefitinib or erlotinib had a significantly longer OS (median: 7.5 months), followed by chemotherapy (5.5 months) and best supportive care (4.0 months) (p < 0.001).

CONCLUSIONS

The prognosis of advanced NSCLC patients after failure of long-term treatment with EGFR-TKI was poor. Chemotherapy with continued EGFR-TKI beyond progression of long-term responders was feasible and led to prolonged OS in advanced NSCLC patients.

Afatinib: a second-generation EGF receptor and ErbB tyrosine kinase inhibitor for the treatment of advanced non-small-cell lung cancer

First-generation reversible EGF receptor (EGFR) tyrosine kinase inhibitors (TKIs) changed our understanding of advanced non-small-cell lung cancer biology and behavior. The presence of sensitizing EGFR mutations in advanced non-small-cell lung cancer defines a subset of patients with a better prognosis and sensitivity to EGFR-TKIs with a better response rate, progression-free survival, quality of life and symptom control than with chemotherapy in the first-line therapy setting. However, current EGFR-TKIs show minimal responses in EGFR wild-type patients or with acquired TKI resistance mediated through the EGFR T790M allele. Afatinib is an irreversible pan-ErbB-TKI, active against wild-type EGFR, sensitizing and T970M-mutant EGFR, ErbB2 and ErbB4 receptors, and represents a step change between reversible first-generation and future irreversible highly specific third-generation EGFR-TKIs. Here, we review the clinical development of afatinib through the LUX-Lung trials portfolio highlighting benefits and toxicities.

Vemurafenib for BRAF V600 mutated advanced melanoma: results of treatment beyond progression

BACKGROUND

Selective BRAF inhibition (BRAFi) by vemurafenib or dabrafenib has become approved standard treatment in BRAF V600 mutated advanced stage melanoma. While the response rate is high, the response duration is limited with a progression-free survival (PFS) of 5-6months. Our observation of accelerated disease progression within some patients after stopping vemurafenib treatment has fostered the idea of treatment beyond progression (BRAFi TBP).

METHOD

In this retrospective study, we analysed 70 metastatic melanoma patients, treated at our institute, who experienced progression after prior objective response upon treatment with vemurafenib. Thirty-five patients that continued treatment beyond progression are compared with 35 patients who stopped BRAFi treatment at disease progression.

RESULTS

Median overall survival beyond documented progression was found to be 5.2months versus 1.4months (95% confidence interval (CI): 3.8-7.4 versus 0.6-3.4; Log-Rank p=0.002) in favour of BRAFi TBP. In the multivariate survival analysis, stopping treatment at disease progression was significantly associated with shorter survival (hazard ratio: 1.92; 95% CI: 1.04-3.55; p=0.04).

CONCLUSION

Our results suggest that continuing vemurafenib treatment beyond progression may be beneficial in advanced melanoma patients, who prior to progression responded to vemurafenib.

Targeted treatment of mutated EGFR-expressing non-small-cell lung cancer: focus on erlotinib with companion diagnostics

Deeper understanding of the pathobiology of non-small-cell lung cancer (NSCLC) has led to the development of small molecules that target genetic mutations known to play critical roles in the progression to metastatic disease. The discovery of epidermal growth factor receptor (EGFR) mutations in 15%–20% of lung adenocarcinomas and the associated response to EGFR tyrosine kinase inhibitors have provided a successful avenue of attack in late-stage adenocarcinomas. Use of the EGFR tyrosine kinase inhibitors gefitinib, erlotinib, and afatinib is limited to patients who have adenocarcinomas with known activating EGFR mutations. However, the EGFR mutation testing landscape is varied and includes many screening and targeted methods, each with its own benefits and limitations. These tests can simplify the drug discovery process, make clinical trials more efficient and informative, and individualize cancer therapy. In practice, the choice of method should be determined by the nature of the sample to be tested, the testing laboratory’s expertise and access to equipment, and whether the detection of only known activating EGFR mutations, or of all possible mutations, is required. Development of companion diagnostic tests for this identification is advancing; nevertheless, the use of such tests merits greater attention.

Subsequent treatment choices for patients with acquired resistance to EGFR-TKIs in non-small cell lung cancer: restore after a drug holiday or switch to another EGFR-TKI?

The outcomes of first-generation EGFR-TKIs (Gefitnib and Erlotinib) have shown great advantages over traditional treatment strategies in patients with non-small cell lung cancer (NSCLC), but unfortunately we have to face the situation that most patients still fail to respond in the long term despite initially good control. Up to now, the mechanism of acquired resistance to EGFR-TKIs has not been fully clarified. Herein, we sought to compile the available clinical reports in the hope to better understanding the subsequent treatment choices, particularly on whether restoring after a drug holiday or switching to another EGFR-TKI is the better option after failure of one kind of EGFR-TKI.

Systemic treatment in EGFR-ALK NSCLC patients: second line therapy and beyond

Lung cancer is the most frequently diagnosed cancer and a leading cause of cancer mortality worldwide, with adenocarcinoma being the most common histological subtype. Deeper understanding of the pathobiology of non-small cell lung cancer (NSCLC) has led to the development of small molecules that target genetic mutations known to play critical roles in progression to metastatic disease and to influence response to targeted therapies. The principle goal of precision medicine is to define those patient populations most likely to respond to targeted therapies. However, the cancer genome landscape is composed of relatively few "mountains" [representing the most commonly mutated genes like KRAS, epidermal growth factor (EGFR), and anaplastic lymphoma kinase (ALK)] and a vast number of "hills" (representing low frequency but potentially actionable mutations). Low-frequency lesions that affect a druggable gene product allow a relatively small population of cancer patients for targeted therapy to be selected.

Gastric Acid suppression is associated with decreased erlotinib efficacy in non-small-cell lung cancer

BACKGROUND

Erlotinib is a key therapy for advanced NSCLC. Concurrent AS therapy with TKIs might reduce TKI plasma levels. Because of gastroesophageal reflux disease prevalence, this retrospective analysis was undertaken to determine if coadministering erlotinib with AS therapy affected NSCLC outcomes.

PATIENTS AND METHODS

Records of advanced NSCLC patients who received erlotinib from 2007 to 2012 at a large, centralized, cancer institution were retrospectively reviewed. Pertinent demographic data were collected and concomitant AS treatment was defined as AS prescription dates overlapping with ≥ 20% of erlotinib treatment duration. Records of patients who received erlotinib for ≥ 1 week were analyzed for progression-free survival (PFS) and overall survival (OS).

RESULTS

Stage IIIB/IV NSCLC patients (n = 544) were identified and 507 had adequate data for review. The median age was 64 years and 272 were female. Adenocarcinoma (n = 318; 64%) and squamous (n = 106; 21%) were predominant subtypes; 124 patients received concomitant AS therapy. In this unselected population, median PFS and OS in AS versus no AS groups were 1.4 versus 2.3 months (P < .001) and 12.9 versus 16.8 months (P = .003), respectively. Factoring sex, subtype, and performance status in multivariate Cox proportional hazards ratios for PFS and OS between AS and no AS groups were 1.83 (95% confidence interval [CI], 1.48-2.25) and 1.37 (95% CI, 1.11-1.69), respectively.

CONCLUSION

This large population-based study suggests erlotinib efficacy might be linked with gastric pH and OS could be adversely affected. To our knowledge, this is the first study demonstrating a possible negative clinical effect of coadministration of erlotinib with AS therapy. Further prospective investigation is warranted.

Triple-negative breast cancer possibly transforming into malignant melanoma due to targeted therapy? A case report and review of literature

BACKGROUND

Triple-negative breast cancer (TNBC) is characterized by lacking expression of estrogen receptor and progesterone receptor as well as absence of human epidermal growth factor receptor 2 overexpression and is an aggressive clinical phenotype.

PATIENTS AND METHODS

We report the case of a 33-year-old woman who has been treated using a targeted approach for TNBC and developed a malignant melanoma metastasis without any primary.

RESULTS AND CONCLUSION

Using targeted therapies, tumors can be treated much more effectively, but up to now, we do not know much about potential adverse reactions. Due to the targeted therapy, tumors may be pressurized for transformation. We call for further investigations to rule out the potential risks of targeted therapy in TNBC. This is the first report of a potential transforming of one tumor entity to another by a targeted therapy.

Gefitinib inhibits invasive phenotype and epithelial-mesenchymal transition in drug-resistant NSCLC cells with MET amplification

Despite the initial response, all patients with epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer (NSCLC) eventually develop acquired resistance to EGFR tyrosine kinase inhibitors (TKIs). The EGFR-T790M secondary mutation is responsible for half of acquired resistance cases, while MET amplification has been associated with acquired resistance in about 5-15% of NSCLCs. Clinical findings indicate the retained addiction of resistant tumors on EGFR signaling. Therefore, we evaluated the molecular mechanisms supporting the therapeutic potential of gefitinib maintenance in the HCC827 GR5 NSCLC cell line harbouring MET amplification as acquired resistance mechanism. We demonstrated that resistant cells can proliferate and survive regardless of the presence of gefitinib, whereas the absence of the drug significantly enhanced cell migration and invasion. Moreover, the continuous exposure to gefitinib prevented the epithelial-mesenchymal transition (EMT) with increased E-cadherin expression and down-regulation of vimentin and N-cadherin. Importantly, the inhibition of cellular migration was correlated with the suppression of EGFR-dependent Src, STAT5 and p38 signaling as assessed by a specific kinase array, western blot analysis and silencing functional studies. On the contrary, the lack of effect of gefitinib on EGFR phosphorylation in the H1975 cells (EGFR-T790M) correlated with the absence of effects on cell migration and invasion. In conclusion, our findings suggest that certain EGFR-mutated patients may still benefit from a second-line therapy including gefitinib based on the specific mechanism underlying tumor cell resistance.

Drug rechallenge and treatment beyond progression--implications for drug resistance

The established dogma in oncology for managing recurrent or refractory disease dictates that therapy is changed at disease progression, because the cancer is assumed to have become drug-resistant. Drug resistance, whether pre-existing or acquired, is largely thought to be a stable and heritable process; thus, reuse of therapeutic agents that have failed is generally contraindicated. Over the past few decades, clinical evidence has suggested a role for unstable, non-heritable mechanisms of acquired drug resistance pertaining to chemotherapy and targeted agents. There are many examples of circumstances where patients respond to reintroduction of the same therapy (drug rechallenge) after a drug holiday following disease relapse or progression during therapy. Additional, albeit limited, evidence suggests that, in certain circumstances, continuing a therapy beyond disease progression can also have antitumour activity. In this Review, we describe the anticancer agents used in these treatment strategies and discuss the potential mechanisms explaining the apparent tumour re-sensitization with reintroduced or continued therapy. The extensive number of malignancies and drugs that challenge the custom of permanently switching to different drugs at each line of therapy warrants a more in-depth examination of the definitions of disease progression and drug resistance and the resulting implications for patient care.

Analysis of tumor specimens at the time of acquired resistance to EGFR-TKI therapy in 155 patients with EGFR-mutant lung cancers

PURPOSE

All patients with EGF receptor (EGFR)-mutant lung cancers eventually develop acquired resistance to EGFR tyrosine kinase inhibitors (TKI). Smaller series have identified various mechanisms of resistance, but systematic evaluation of a large number of patients to definitively establish the frequency of various mechanisms has not been conducted.

EXPERIMENTAL DESIGN

Patients with lung adenocarcinomas and acquired resistance to erlotinib or gefitinib enrolled onto a prospective biopsy protocol and underwent a rebiopsy after the development of acquired resistance. Histology was reviewed. Samples underwent genotyping for mutations in EGFR, AKT1, BRAF, ERBB2, KRAS, MEK1, NRAS and PIK3CA, and FISH for MET and HER2.

RESULTS

Adequate tumor samples for molecular analysis were obtained in 155 patients. Ninety-eight had second-site EGFR T790M mutations [63%; 95% confidence interval (CI), 55%-70%] and four had small cell transformation (3%, 95% CI, 0%-6%). MET amplification was seen in 4 of 75 (5%; 95% CI, 1%-13%). HER2 amplification was seen in 3 of 24 (13%; 95% CI, 3%-32%). We did not detect any acquired mutations in PIK3CA, AKT1, BRAF, ERBB2, KRAS, MEK1, or NRAS (0 of 88, 0%; 95% CI, 0%-4%). Overlap among mechanisms of acquired resistance was seen in 4%.

CONCLUSIONS

This is the largest series reporting mechanisms of acquired resistance to EGFR-TKI therapy. We identified EGFR T790M as the most common mechanism of acquired resistance, whereas MET amplification, HER2 amplification, and small cell histologic transformation occur less frequently. More comprehensive methods to characterize molecular alterations in this setting are needed to improve our understanding of acquired resistance to EGFR-TKIs.

Local therapy with continued EGFR tyrosine kinase inhibitor therapy as a treatment strategy in EGFR-mutant advanced lung cancers that have developed acquired resistance to EGFR tyrosine kinase inhibitors

BACKGROUND

Development of acquired resistance limits the utility of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKI) for the treatment of EGFR-mutant lung cancers. There are no accepted targeted therapies for use after acquired resistance develops. Metastasectomy is used in other cancers to manage oligometastatic disease. We hypothesized that local therapy is associated with improved outcomes in patients with EGFR-mutant lung cancers with acquired resistance to EGFR TKI.

METHODS

Patients who received non-central nervous system local therapy were identified by a review of data from a prospective biopsy protocol for patients with EGFR-mutant lung cancers with acquired resistance to EGFR TKI therapy and other institutional biospecimen registry protocols.

RESULTS

Eighteen patients were identified, who received elective local therapy (surgical resection, radiofrequency ablation, or radiation). Local therapy was well tolerated, with 85% of patients restarting TKI therapy within 1 month of local therapy. The median time to progression after local therapy was 10 months (95% confidence interval [CI]: 2-27 months). The median time until a subsequent change in systemic therapy was 22 months (95% CI: 6-30 months). The median overall survival from local therapy was 41 months (95% CI: 26-not reached).

CONCLUSIONS

EGFR-mutant lung cancers with acquired resistance to EGFR TKI therapy are amenable to local therapy to treat oligometastatic disease when used in conjunction with continued EGFR inhibition. Local therapy followed by continued treatment with an EGFR TKI is well tolerated and associated with long PFS and OS. Further study in selected individuals in the context of other systemic options is required.

Epidermal growth factor receptor tyrosine kinase inhibitor-resistant disease

PURPOSE

EGFR-mutant lung cancer was first described as a new clinical entity in 2004. Here, we present an update on new controversies and conclusions regarding the disease.

METHODS

This article reviews the clinical implications of EGFR mutations in lung cancer with a focus on epidermal growth factor receptor tyrosine kinase inhibitor resistance.

RESULTS

The discovery of EGFR mutations has altered the ways in which we consider and treat non-small-cell lung cancer (NSCLC). Patients whose metastatic tumors harbor EGFR mutations are expected to live longer than 2 years, more than double the previous survival rates for lung cancer.

CONCLUSION

The information presented in this review can guide practitioners and help them inform their patients about EGFR mutations and their impact on the treatment of NSCLC. Efforts should now concentrate on making EGFR-mutant lung cancer a chronic rather than fatal disease.