Phase II study of a combination regimen of gefitinib and pemetrexed as first-line treatment in patients with advanced non-small cell lung cancer harboring a sensitive EGFR mutation

Efficacy and safety analyses of epidermal growth factor receptor tyrosine kinase inhibitors combined with chemotherapy in the treatment of advanced non-small-cell lung cancer with an EGFR/TP53 co-mutation

PURPOSE

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) combined with cytotoxic chemotherapy are highly effective in the treatment of advanced non-small-cell lung cancer (NSCLC) with EGFR mutations. The purpose of this study is to evaluate the efficacy and safety of this combination in advanced NSCLC patients with an EGFR/TP53 co-mutation.

METHODS

Ninety-five advanced NSCLC patients with an EGFR/TP53 co-mutation were enrolled in this study. Treatments with either EGFR-TKI monotherapy (T group, n = 61) or EGFR-TKI combined with chemotherapy (TC group, n = 34) were evaluated in relation to objective response rate (ORR), disease control rate (DCR), median time to progression (TTP), and median overall survival (OS).

RESULTS

There were no statistically significant differences in DCR between the treatment groups. The ORR was significantly improved in the TC group versus the T group (55.9% vs. 34.4%, P = 0.042). A higher median TTP was noted in TC group compared with T group (16.1 vs. 11.1 months, P = 0.002). Patients without brain metastases in TC group had a longer median OS than in T group (48.4 vs. 28.8 months, P = 0.003). However, there was a non-significant trend towards longer OS in TC group in the entire cohort (36.9 vs. 28.2 months, P = 0.078). Cox multivariate regression analysis showed that clinical stage, brain metastases, EGFR21 L858R mutation, and T790M status at first progression were independent risk factors for OS. However, the incidence of grade 3 or higher adverse events were higher in the TC group than in the T group (32.4% vs. 13.1%, P = 0.025).

CONCLUSION

Our study indicates that EGFR-TKIs combined with chemotherapy could significantly improve the ORR and TTP of advanced NSCLC patients with an EGFR/TP53 co-mutation. Combination therapy may be a promising treatment for advanced NSCLC patients with an EGFR/TP53 co-mutation without brain metastases.

Treatment Sequencing Strategies in Lung Cancer

BACKGROUND

The advances in the lung cancer screening methods and therapeutics, together with awareness towards deleterious habits, such as smoking, is increasing the overall survival with better quality of life for the patients. However, lung cancer is still one of the most common and fatal neoplasm with a high incidence and consequently burden to public health worldwide. Thus, based on guidelines and recent phases II and III clinical trials studies, this manuscript summarizes the current treatment sequencing strategies in lung cancer.

METHODS

A comprehensive search of related articles was performed focused on phases II and III clinical trials studies.

RESULTS

The lung cancer management should take into consideration the tumor characteristics, histology, molecular pathology and be discussed in a multidisciplinary team. Lung cancer treatment options comprises surgery whenever possible, radiotherapy associate with/or chemotherapy and immunotherapy as monotherapy, or combined with chemotherapy and best palliative care.

CONCLUSIONS

The screening predictability in more patients, smoking reduction, early diagnosis, better disease understanding and individualized, more effective and tolerable therapeutics are related to an increasing in overall survival and quality of life. In the near future improvement of personalized therapy in precision medicine is expected, enhancing new predictive biomarkers, optimal doses and optimal treatment sequencing as well as anti-cancer vaccines development.

The Relationship Between Short-Term Surrogate Endpoint Indicators and mPFS and mOS in Clinical Trials of Malignant Tumors: A Case Study of Approved Molecular Targeted Drugs for Non-Small-Cell Lung Cancer in China

Objective: Due to the initiation of the priority review program in China, many antitumor drugs have been approved for marketing based on phase II clinical trials and short-term surrogate endpoint indicators. This study used approved targeted drugs for the treatment of non-small-cell lung cancer (NSCLC) in China as an example to evaluate the association between short-term surrogate endpoints [objective response rate (ORR) and disease control rate (DCR)] and median progression-free survival (mPFS) and median overall survival (mOS). Methods: Five databases, i.e., MEDLINE, Embase, Cochrane Library, China National Knowledge Infrastructure (CNKI), and Wanfang Data were searched, for phase II or phase III clinical trials of all molecular targeted drugs that have been marketed in China for the treatment of NSCLC. After screening the literature and extracting information, both univariate and multivariate linear regression were performed on the short-term surrogate indicators and mPFS and mOS to explore the relationship. Results: A total of 63 studies were included (25 studies with only ORR, DCR, and mPFS and 39 studies with ORR, DCR, mPFS, and mOS). In terms of the targeted drugs for the treatment of NSCLC, in addition to the good but not excellent linear relationship between DCR and mOS (0.4 < R2 adj = 0.5653 < 0.6), all other short-term surrogate endpoint indicators had excellent linear relationships with mPFS and mOS (R2 adj≥0.6), while mPFS and mOS had the most excellent linear relationships (R2 adj = 0.8036). Conclusion: For targeted drugs for the treatment of NSCLC, short-term surrogate endpoint indicators such as ORR and DCR may be reliable surrogate indicators for mPFS and mOS. However, whether short-term surrogate endpoint indicators can be used to predict final endpoints remains to be verified.

A review on epidermal growth factor receptor's role in breast and non-small cell lung cancer

Epithelial growth factor receptor (EGFR) is a cell surface transmembrane receptor that mediates the tyrosine signaling pathway to carry the extracellular messages inside the cell and thereby alter the function of nucleus. This leads to the generation of various protein products to up or downregulate the cellular function. It is encoded by cell erythroblastosis virus oncogene B1, so called C-erb B1/ERBB2/HER-2 gene that acts as a proto-oncogene. It belongs to the HER-2 receptor-family in breast cancer and responds best with anti-Herceptin therapy (anti-tyrosine kinase monoclonal antibody). HER-2 positive breast cancer patient exhibits worse prognosis without Herceptin therapy. Similar incidence and prognosis are reported in other epithelial neoplasms like EGFR + lung non-small cell carcinoma and glioblastoma (grade IV brain glial tumor). Present study highlights the role and connectivity of EGF with various cancers via signaling pathways, cell surface receptors mechanism, macromolecules, mitochondrial genes and neoplasm. Present study describes the EGFR associated gene expression profiling (in breast cancer and NSCLC), relation between mitrochondrial genes and carcinoma, and several in vitro and in vivo models to screen the synergistic effect of various combination treatments. According to this study, although clinical studies including targeted treatments, immunotherapies, radiotherapy, TKi-EGFR combined targeted therapy have been carried out to investigate the synergism of combination therapy; however still there is a gap to apply the scenarios of experimental and clinical studies for further developments. This review will give an idea about the transition from experimental to most advanced clinical studies with different combination drug strategies to treat cancer.

Hype or hope - Can combination therapies with third-generation EGFR-TKIs help overcome acquired resistance and improve outcomes in EGFR-mutant advanced/metastatic NSCLC?

Three generations of epidermal growth factor receptor - tyrosine kinase inhibitors (EGFR-TKIs) have been developed for treating advanced/metastatic non-small cell lung cancer (NSCLC) patients harboring EGFR-activating mutations, while a fourth generation is undergoing preclinical assessment. Although initially effective, acquired resistance to EGFR-TKIs usually arises within a year due to the emergence of clones harboring multiple resistance mechanisms. Therefore, the combination of EGFR-TKIs with other therapeutic agents has emerged as a potential strategy to overcome resistance and improve clinical outcomes. However, results obtained so far are ambiguous and ideal therapies for patients who experience disease progression during treatment with EGFR-TKIs remain elusive. This review provides an updated landscape of EGFR-TKIs, along with a description of the mechanisms causing resistance to these drugs. Moreover, it discusses the current knowledge, limitations, and future perspective regarding the use of EGFR-TKIs in combination with other anticancer agents, supporting the need for bench-to-bedside approaches in selected populations.

Concurrent chemotherapy and first-generation epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) with or without an antiangiogenic agent as first-line treatment in advanced lung adenocarcinoma harboring an EGFR mutation

BACKGROUND

Previous studies have demonstrated the combination of epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) and other antitumor agents may delay drug resistance. In this study, we retrospectively reviewed the efficacy and safety of first-line concurrent EGFR-TKIs and platinum-based doublet chemotherapy with or without an antiangiogenic agent for advanced lung adenocarcinoma patients in the real world.

METHODS

A total of 30 patients with advanced lung adenocarcinoma and activating EGFR mutations concurrently received an EGFR-TKI and platinum-based doublet chemotherapy with or without bevacizumab. The safety profile and efficacy were retrospectively reviewed.

RESULTS

At the median follow-up time of 22.1 months, 18 patients had experienced disease progression, and six patients had died because of disease. The median progression-free survival (mPFS) was 21.2 months (95% CI: 12.631-29.798). Of the 28 patients who had measurable lesions, the objective response rate and disease control rate were 71.4% and 96.4%, respectively (one patient achieved complete remission, 19 patients had a partial response and seven patients had stable disease). Male patients had significantly longer mPFS than female patients (32.6 vs. 14.6 months, HR = 3.593, 95% CI: 1.158-11.148, p = 0.027). The most frequently seen grade 3/4 adverse events were hematological toxicities, seen in three cases (10%). Three patients ceased bevacizumab due to vascular events, including hypertension (grade 2, 6.7%) and venous thrombosis (grade 2, 3.3%), and continued EGFR-TKI and platinum-based doublet chemotherapy.

CONCLUSIONS

The combination of first-generation EGFR-TKIs with platinum-based chemotherapy may be a first-line treatment for advanced lung adenocarcinoma patients harboring activated EGFR mutations and is well tolerated.

The treatment of advanced lung adenocarcinoma with activating EGFR mutations

INTRODUCTION

Lung adenocarcinomas account for approximately 40-50% of all NSCLC (Non-Small Cell Lung Cancer) cases. In addition, lung adenocarcinomas can harbor several different genetic mutations, EGFR (Epidermal Growth Factor Receptor) being the most frequent one, accounting for approximately 5-15% of all the mutations in western patients and for approximately 40-55% in Asian patients; on the other hand, EGFR mutations are uncommon in squamous histology. Approximately 90% of EGFR mutations are represented by exon 19 in-frame deletion and by the L858R exon 21-point mutation, that confer sensitivity to EGFR TKI (Tyrosine Kinase Inhibitors) treatment.

AREAS COVERED

The authors comprehensively review the current state of the art with reference to EGFR+ NSCLC treatment and to discuss the possible future developments.

EXPERT OPINION

Osimertinib must be considered the preferred first-line agent in EGFR+ advanced NSCLC patients thanks to its superior performances. With respect to acquired resistance mechanisms to osimertinib, the currently ongoing clinical trials will surely help us to better understand and tackle them. Globally, we strongly believe that a biomarker-driven sequential treatment algorithm is key in order to provide personalized, effective and durable therapies in the increasingly complex landscape of EGFR+ advanced NSCLC.

Reporting of Incidence and Outcome of Bone Metastases in Clinical Trials Enrolling Patients with Epidermal Growth Factor Receptor Mutated Lung Adenocarcinoma-A Systematic Review

Bone metastases, occurring in 30-60% of patients with non-small cell lung cancer (NSCLC), are associated with decreased survival, cancer-induced bone pain, and skeletal-related events (SREs). Those with an activating epidermal growth factor mutation (EGFR+) seem to be more prone to develop bone metastases. To gain more insight into bone metastases-related outcomes in EGFR+ NSCLC, we performed a systematic review on Pubmed (2006-2021). Main inclusion criteria: prospective, phase II/III trials evaluating EGFR-tyrosine kinase inhibitors, ≥10 EGFR+ patients included, data on bone metastases and/or bone-related outcomes available. Out of 663 articles, 21 (3176 EGFR+ patients) met the eligibility criteria; 4 phase III (one double blind), 17 phase II trials (three randomized) were included. In seven trials dedicated bone imaging was performed at baseline. Mean incidence of bone metastases at diagnosis was 42%; 3-33% had progression in the bone upon progression. Except for one trial, it was not specified whether the use of bone target agents was permitted, and in none of the trials, occurrence of SREs was reported. Despite the high incidence of bone metastases in EGFR+ adenocarcinoma, there is a lack of screening for, and reporting on bone metastases in clinical trials, as well as permitted bone-targeted agents and SREs.

Efficacy and acquired resistance of EGFR-TKI combined with chemotherapy as first-line treatment for Chinese patients with advanced non-small cell lung cancer in a real-world setting

Background

To compare the benefits and explore the cause of acquired resistance of epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) and its combination with chemotherapy in advanced non-small-cell lung cancer (NSCLC) patients harboring EGFR mutation in a real-life setting.

Methods

This retrospective analysis included 117 advanced NSCLC patients with EGFR mutation who underwent next-generation sequencing (NGS) prior to treatment. The combination group included 50 patients who received the regimen of EGFR-TKI combined with chemotherapy, while the EGFR-TKI monotherapy group included 67 patients treated with TKI only. The primary endpoint of this study was progression-free survival (PFS); the secondary endpoints were overall survival (OS), response rate, and toxicity.

Results

The median PFS was significantly longer in the combination group than in the EGFR-TKI monotherapy group (19.00 months [95% CI, 14.67–23.33] vs. 11.70 months [95% CI, 10.81–12.59], p < 0.001). Subgroup analysis showed a similar trend of results. The median OS was not reached in the combination group and was 38.50 (95% CI, 35.30–41.70) months in the EGFR-TKI monotherapy group (p = 0.586). Patients in the combination group were more likely to experience adverse events, most of which showed the severity of grade 1 or 2. T790M mutation remains the main reason for acquired resistance, and the frequency of T790M mutation was similar between the two groups (p = 0.898).

Conclusions

Compared with EGFR-TKI monotherapy, EGFR-TKI combined with chemotherapy significantly improved PFS in advanced NSCLC patients with EGFR mutation, with acceptable toxicity.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08291-9.

Outcomes of concurrent versus sequential icotinib therapy and chemotherapy in advanced non-small cell lung cancer with sensitive EGFR mutations

Abstract

To explore a better treatment strategy for patients with advanced non‐small cell lung cancer harboring sensitive epidermal growth factor receptor mutations, a total of 271 patients were retrospectively analyzed. The patients were divided into two groups: the combination group (58 cases), which received concurrent icotinib, pemetrexed, and platinum treatment, and the sequential group (213 cases), which received the sequential pemetrexed and platinum therapy, followed by icotinib treatment. The primary end points were progression‐free survival (PFS) and PFS on the subsequent line of therapy (PFS2). PFS in the combination group was significantly higher compared with that in the sequential group (16.89 months vs. 9.90 months; p < 0.001). PFS in the combination group was also significantly higher than PFS2 in the sequential group (16.89 months vs. 14.05 months; p = 0.009). The overall survival (OS) of the patients was 33.22 months (95% confidence interval (CI): 26.99–37.01) in the combination group and 26.47 months (95% CI: 25.05–26.95) in the sequential group (p < 0.001). The combination group’s objective response rate was superior to that of the sequential group (79.31% vs. 52.11%; p < 0.001). Propensity score matching also revealed that icotinib therapy combined with chemotherapy extended the PFS, PFS2, and OS of the patients (p < 0.0001, p = 0.003, and p = 0.001, respectively). The combination group’s objective response rate was also better compared with the sequential group (79.31% vs. 51.72%; p = 0.001). In conclusion, our study demonstrated icotinib combined with chemotherapy can improve survival efficacy better than the separated two‐line therapy.

Chemotherapy Plus EGFR-TKI as First-Line Treatment Provides Better Survival for Advanced EGFR-Positive Lung Adenocarcinoma Patients: Updated Data and Exploratory In Vitro Study

BACKGROUND

Previously, we demonstrated that treatment with gefitinib combined with pemetrexed plus carboplatin chemotherapy improved progression-free survival (PFS) compared to gefitinib or chemotherapy alone in lung adenocarcinoma patients with sensitizing EGFR mutations.

OBJECTIVE

In the present study, we updated the long-term overall survival (OS) of the combination therapy and the gefitinib groups. Furthermore, the possible mechanisms underlying the effects of combination therapy were investigated.

PATIENTS AND METHODS

Lung adenocarcinoma patients harboring sensitizing EGFR mutations received either gefitinib plus chemotherapy (n = 40) or gefitinib alone (n = 41), and long-term survival was assessed. The pharmacological interaction between gefitinib and pemetrexed was evaluated in the PC-9 lung adenocarcinoma cell line using a colorimetric assay for assessing cell metabolic activity (MTT assay). The influence of combined treatment with gefitinib plus pemetrexed on gene expression profiles and signaling pathways was investigated using microarrays and Ingenuity Pathway Analysis (IPA).

RESULTS

On the last day of follow-up (28 September 2018), 30 (75.0%) patients in the combination group and 35 (85.4%) patients in the gefitinib group had died. The 2-year and 3-year survival rates of the combination versus gefitinib were 85.0% versus 56.1% (P = 0.004) and 52.5% versus 24.4% (P = 0.009), respectively. The median OS was 37.9 months (95% CI: 17.3-58.6) for the combination group and 25.8 months (95% CI: 19.2-32.3) for the gefitinib group (HR = 0.56, 95% CI: 0.34-0.91, P = 0.02). A synergistic inhibitory effect between gefitinib and pemetrexed was observed in the lung adenocarcinoma cell line PC-9. Furthermore, widespread gene expression changes and critical signaling pathways such as AKT signaling were identified, which might be responsible for the synergism seen with the combination treatment.

CONCLUSIONS

Combined treatment with gefitinib plus pemetrexed resulted in improved OS over gefitinib alone. A synergistic inhibitory effect between gefitinib and pemetrexed was observed on lung adenocarcinoma cell growth. Gene expression profile analysis revealed potential signaling pathways, including AKT signaling, contributing to the synergism.

CLINICAL TRIAL REGISTRATION NUMBER

NCT02148380.

Multikinase inhibitor-induced liver injury in patients with cancer: A review for clinicians

BACKGROUND

Multikinase inhibitors (MKI) are targeted molecular agents that have revolutionized cancer management. However, there is a paucity of data concerning MKI-related liver injury risk and clinical guidelines for the management of liver toxicity in patients receiving MKI for cancer are scarce.

DESIGN

We conducted a PubMed search of articles in English published from January 2000 to December 2018 related to hepatotoxicity of the 29 FDA-approved MKIs at doses used in clinical practice. The search terms were the international non-proprietary name of each agent cross-referenced with «hepatotoxicity», «hepatitis», «hepatic adverse event», or «liver failure», and «phase II clinical trial», «phase III clinical trial», or «case report».

RESULTS

Following this search, 140 relevant studies and 99 case reports were considered. Although asymptomatic elevation of aminotransferase levels has been frequently observed in MKI clinical trials, clinically significant hepatotoxicity is a rare event. In most cases, the interval between treatment initiation and the onset of liver injury is between one week and two months. Liver toxicity is often hepatocellular and less frequently mixed. Life-threatening MKI-induced hepatic injury has been described, involving fulminant liver failure or death. Starting from existing data, a description of MKI-related liver events, grading of hepatotoxicity risk, and recommendations for management are also given for various MKI molecules.

CONCLUSION

All MKIs can potentially cause liver injury, which is sometimes irreversible. As there is still no strategy available to prevent MKI-related hepatotoxicity, early detection remains crucial. The surveillance of liver function during treatment may help in the early detection of hepatotoxicity. Furthermore, the exclusion of potential causes of hepatic injury is essential to avoid unnecessary MKI withdrawal.

Combination of EGFR-TKIs and chemotherapy in advanced EGFR mutated NSCLC: Review of the literature and future perspectives

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) improved clinical outcome compared to chemotherapy in EGFR mutated advanced non-small cell lung cancer (NSCLC) patients. Nonetheless, acquired resistance develops within 10-14 months and 20-30% of EGFR-mutated patients do not respond to EGFR-TKI. In order to delay or overcome acquired resistance to EGFR-TKIs, combination therapies of EGFR-TKIs with chemotherapy has been investigated with conflicting results. Early studies failed to show a survival benefit because of a lack of patient selection, but more recently clinical studies in EGFR mutated patients have shown promising results. This review summarizes preclinical and clinical studies of combination of EGFR-TKIs, including the third-generation TKI osimertinib, with chemotherapy in first- and second-line settings, using concurrent or intercalated treatment strategies. In the new era of third-generation EGFR-TKIs, new studies of this combination strategy are warranted.

Advanced Non-Small Cell Lung Cancer with Activating Epidermal Growth Factor Receptor Mutation: First Line Treatment and Beyond

BACKGROUND

Lung cancer is the leading cause of cancer mortality, being responsible for more than 1.6 million deaths each year worldwide and non-small-cell lung cancer (NSCLC) accounts for approximately 85% of lung cancers; moreover, 10 to 15% of all NSCLCs harbor EGFR (epidermal growth factor receptor) activating mutations, being suitable for EGFR-Tyrosine Kinase Inhibitors (TKI) molecular targeted therapy. However, EGFR+ NSCLCs gain acquired resistance to these agents, representing one of the key challenges for modern precision oncology.

OBJECTIVE

Therefore, this paper aims to provide an extensive state of the art review, alongside with hints about future perspectives.

CONCLUSION

To date, in the light of the data from the FLAURA study, osimertinib represents the best first-line option in NSCLC patients with EGFR activating mutations; EGFR-TKI plus chemotherapy combination therapies, even though interesting, must still be considered investigational.

Efficacy of first-line treatment with epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) alone or in combination with chemotherapy for advanced non-small cell lung cancer (NSCLC) with low-abundance mutation

OBJECTIVE

The objective of this study was to investigate whether first-line treatment with epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) in combination with chemotherapy improves the prognosis of patients with advanced non-small cell lung cancer (NSCLC) who harbour low-abundance EGFR mutations.

PATIENTS AND METHODS

We retrospectively analysed the clinical data of 76 patients with advanced NSCLC who harboured low-abundance EGFR mutations. The patients were divided into the combination group and the monotherapy group. The combination group received EGFR-TKI combined with a platinum-based regimen. After the end of chemotherapy, EGFR-TKI was administered daily. The monotherapy group was administered EGFR-TKI therapy daily.

RESULTS

No significant difference was observed in response rate between the different groups. The median PFS and OS were significantly longer in the combination group than in the monotherapy group (PFS: 7.9 months [95% CI,5.73-10.07] vs 5.9 months [95% CI, 4.99-6.81], p = 0.015; OS: 25.8 months[95% CI,16.27-35.33] vs 19.8 months [95% CI, 18.60-21.00], p = 0.047). Subgroup analysis showed that, for patients with the exon 21 L858R mutation, the PFS and OS were significantly longer in the combination group than in the monotherapy group (PFS: 7.2 months vs 5.8 months, p = 0.013; OS: 22.0 months vs 18.7 months, p = 0.024). The incidence of adverse events was significantly higher in the combination group.

CONCLUSION

For patients with advanced NSCLC and low-abundance EGFR mutations, first-line treatment with EGFR-TKI plus chemotherapy significantly improved PFS and OS. The combination therapy increased the incidence of adverse reactions, but all adverse reactions were expected and tolerated.

Efficacy of combined icotinib and pemetrexed in EGFR mutant lung adenocarcinoma cell line xenografts

Background

The combination of EGFR tyrosine kinase inhibitors (TKIs) and chemotherapy is thought to increase treatment efficacy in non‐small‐cell lung cancer (NSCLC). This study investigated the efficacy and potential mechanisms of different combined modes of icotinib plus pemetrexed in EGFR‐mutant lung adenocarcinoma cell line xenograft models.

Methods

Nude mice were subcutaneously injected with EGFR‐mutant human lung adenocarcinoma cells (HCC827) and randomized into six treatment groups. Tumor xenograft volumes were monitored and recorded. Microvessel density (MVD) and proliferation and apoptosis rates were evaluated with CD34 positive cell counting, and Ki‐67 and caspase‐3 scores, respectively, and determined via immunohistochemistry. Thymidylate synthase (TS), EGFR, and downstream signaling molecule expression was detected by Western blotting.

Results

The volume and weight of tumor xenografts in the sequential pemetrexed followed by icotinib (Pem‐Ico) group and the concurrent icotinib and pemetrexed (Ico + Pem) group were significantly smaller than those in the control, pemetrexed (Pem), icotinib (Ico), and sequential icotinib followed by pemetrexed (Ico‐Pem) groups. Compared to other groups, a decrease in the MVD and proliferation rate and an increase in the apoptosis rate were observed in the Pem‐Ico and Ico + Pem groups. TS expression and EGFR, AKT, and MAPK phosphorylation were significantly reduced in the Pem‐Ico or Ico + Pem groups.

Conclusions

Pem‐Ico had additive antitumor activity in vivo, similar to Ico + Pem, both of which are suggested as potentially optimized strategies for treating EGFR‐mutant lung adenocarcinoma.

EGFR-TKIs plus chemotherapy demonstrated superior efficacy than EGFR-TKIs alone as first-line setting in advanced NSCLC patients with EGFR mutation and BIM deletion polymorphism

BACKGROUND

Non-small-cell lung cancer (NSCLC) patients with both epidermal growth factor receptor (EGFR) positive mutation and B-cell chronic lymphocytic leukemia/lymphoma-like 11 (BIM) deletion polymorphism had a poor clinical response to EGFR-tyrosine kinase inhibitors (TKIs). The current study aimed to investigate the clinical efficacy and tolerability of EGFR-TKIs plus chemotherapy versus EGFR-TKIs alone as first-line treatment in advanced NSCLC patients with EGFR mutations and BIM deletion polymorphism.

METHODS

A retrospective, non-randomized analysis was conducted. BIM deletion polymorphism was detected using polymerase chain reaction (PCR) analysis and direct sequencing of DNA from peripheral blood cells. Clinical characteristics, overall survival (OS), progress-free-survival (PFS), objective response rate (ORR) and treatment-related adverse events were compared between EGFR-TKIs alone versus EGFR-TKIs plus chemotherapy group.

RESULTS

65 patients were enrolled. 36 of them received EGFR-TKIs and 29 received EGFR-TKIs plus chemotherapy. EGFR-TKIs plus chemotherapy had significantly higher ORR than TKIs alone (65.5% vs. 38.9%, P = 0.046). Median PFS was significantly longer in EGFR-TKIs plus chemotherapy group than in TKIs group (7.2 vs 4.7 m; P = 0.008). Median OS was numerically longer in EGFR-TKIs plus chemotherapy group than in TKIs alone (18.5 vs 14.2 m; P = 0.107). EGFR-TKIs plus chemotherapy was associated with more grade 3 or 4 hematological toxic effects than EGFR-TKIs alone.

CONCLUSION

EGFR-TKIs plus chemotherapy conferred a significantly higher ORR, prolonged PFS and numerically longer OS in advanced NSCLC patients with EGFR mutation and BIM deletion polymorphism. Further prospective studies are needed to validate these findings.

Updated survival outcomes of NEJ005/TCOG0902: a randomised phase II study of concurrent versus sequential alternating gefitinib and chemotherapy in previously untreated non-small cell lung cancer with sensitive EGFR mutations

Background

The North-East Japan Study Group (NEJ) 005/Tokyo Cooperative Oncology Group (TCOG) 0902 study has reported that first-line concurrent and sequential alternating combination therapies of an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (gefitinib) plus platinum-based doublet chemotherapy (carboplatin/pemetrexed) offer promising efficacy with predictable toxicities for patients with EGFR-mutant non-small cell lung cancer. However, overall survival (OS) data were insufficient in the primary report because of the lack of death events.

Patients and methods

Progression-free survival (PFS) and OS were re-evaluated at the final data cut-off point (March 2017) for the entire population (n=80).

Results

At the median follow-up time of 35.6 months, 88.8% of patients had progressive disease and 77.5% of patients had died. Median PFS was 17.5 months for the concurrent regimen and 15.3 months for the sequential alternating regimen (P=0.13). Median OS was 41.9 and 30.7 months, respectively (P=0.036). Updated response rates were similar in both groups (90.2% and 82.1%, respectively; P=0.34). Patients with Del19 tumours displayed relatively better OS (median: 45.3 vs 33.3 months, respectively) than those with L858R (31.4 vs 28.9 months, respectively). No severe adverse events, including interstitial lung disease, occurred in the period since the primary report.

Conclusions

This updated analysis confirms that PFS is improved with first-line combination therapy compared with gefitinib monotherapy and that the concurrent regimen, in particular, offers an OS benefit of 42 months in the EGFR-mutated setting. Our ongoing NEJ009 study will clarify whether this combination strategy can be incorporated into routine clinical practice.

Trial registration number

UMIN C000002789, Post-results.

Combination Strategies Using EGFR-TKi in NSCLC Therapy: Learning from the Gap between Pre-Clinical Results and Clinical Outcomes

Although epidermal growth factor receptor (EGFR) inhibitors have been used to treat non-small cell lung cancer (NSCLC) for decades with great success in patients with EGFR mutations, acquired resistance inevitably occurs after long-term exposure. More recently, combination therapy has emerged as a promising strategy to overcome this issue. Several experiments have been carried out to evaluate the synergism of combination therapy both in vitro and in vivo. Additionally, many clinical studies have been carried out to investigate the feasibility of treatment with EGFR-tyrosine kinase inhibitors (TKi) combined with other NSCLC treatments, including radiotherapy, cytotoxic chemotherapies, targeted therapies, and emerging immunotherapies. However, a significant gap still exists when applying pre-clinical results to clinical scenarios, which hinders the development and use of these strategies. This article is a literature review analysing the rationalities and controversies in the transition from pre-clinical investigation to clinical practice associated with various combination strategies. It also highlights clues and challenges regarding future combination therapeutic options in NSCLC treatment.

A systematic review of targeted agents for non-small cell lung cancer

BACKGROUND

advanced-stage non-small cell lung cancer (NSCLC) is characterized by having limited treatment options and thus a poor prognosis. However, new treatment options, in the form of targeted agents (TA), have emerged during recent years. This systematic review aims to provide an overview of the accessible literature in PubMed evaluating TA used on NSCLC patients, and the resulting survival outcomes.

METHOD

this systematic literature review was conducted by reviewing all relevant literature in PubMed. Six separate searches were performed: Three searches where controlled entry terms were used and three free text searches. Furthermore, other relevant publications were included manually. A total of seventy-two studies met the search criteria and were thus further analyzed and evaluated.

RESULTS

In the included studies, various TAs and their effect on different molecular targets have been evaluated. Clinical responses vary considerably among the different genetic aberrations. The majority of studies evaluated TA for epidermal growth factor receptor (EGFR) mutations and TA for echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase (EML4-ALK) rearrangements. Studies regarding the use of TA for Rat sarcoma (RAS), rapidly accelerated fibrosarcoma (RAF), ROS proto-oncogene 1 (ROS1) rearrangement, Receptor tyrosine-protein kinase erbB-2 (ERBB2), Phosphatidylinositol 3-kinase (PIK3CA)/v-akt murine thymoma viral oncogene homolog; protein kinase B(AKT)/Phosphatase and tensin homolog deleted on chromosome 10(PTEN), The mammalian target of rapamycin (mTOR), and Mesenchymal-epithelial transition factor (MET) were included as well. In general, studies comparing treatment outcomes in EGFR-mutated patients and EML4-ALK (ALK) rearranged patients after use of either TA or standard chemotherapy, present significant better results after TA.

CONCLUSIONS

This systematic review provides an overview of available literature in PubMed regarding NSCLC and TA. Included studies point toward that TA appears to be a promising therapeutic tool in treating NSCLC patients and use of TA is expected to result in improved treatment outcomes.

First-line therapy for advanced non-small cell lung cancer with activating EGFR mutation: is combined EGFR-TKIs and chemotherapy a better choice?

As the standard first-line treatment for advanced non-small cell lung cancer (NSCLC) with activating epidermal growth factor receptor (EGFR) mutation, EGFR-tyrosine kinase inhibitors (EGFR-TKIs) have significantly improved the median progression-free survival (PFS) up to 18.9 months. However, almost all patients eventually develop acquired resistance to EGFR-TKIs, which limits the first-line PFS. To overcome the resistance and improve overall survival, researchers have tried to identify the resistance mechanisms and develop new treatment strategies, among which a combination of EGFR-TKIs and cytotoxic chemotherapy is one of the hotspots. The data from preclinical and clinical studies on combined EGFR-TKIs and chemotherapy have shown very interesting results. Here, we reviewed the available preclinical and clinical studies on first-line EGFR-TKIs-chemotherapy combination in patients with advanced NSCLC harboring activating EGFR mutation, aiming to provide evidences for more potential choices and shed light on clinical treatment.

Sequentially administrated of pemetrexed with icotinib/erlotinib in lung adenocarcinoma cell lines in vitro

Combination of chemotherapy and epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) had been proved to be a potent anti-drug for the treatment of tumors. However, survival time was not extended for the patients with lung adenocarcinoma (AdC) compared with first-line chemotherapy. In the present study, we attempt to assess the optimal schedule of the combined administration of pemetrexed and icotinib/erlotinib in AdC cell lines. Human lung AdC cell lines with wild-type (A549), EGFR T790M (H1975) and activating EGFR mutation (HCC827) were applied in vitro to assess the differential efficacy of various sequential regimens on cell viability, cell apoptosis and cell cycle distribution. The results suggested that the antiproliferative effect of the sequence of pemetrexed followed by icotinib/erlotinib was more effective than that of icotinib/erlotinib followed by pemetrexed. Additionally, a reduction of G1 phase and increased S phase in sequence of pemetrexed followed by icotinib/erlotinib was also observed, promoting cell apoptosis. Thus, the sequential administration of pemetrexed followed by icotinib/erlotinib exerted a synergistic effect on HCC827 and H1975 cell lines compared with the reverse sequence. The sequential treatment of pemetrexed followed by icotinib/erlotinib has been demonstrated promising results. This treatment strategy warrants further confirmation in patients with advanced lung AdC.

Selection of Non-small Cell Lung Cancer Patients for Intercalated Chemotherapy and Tyrosine Kinase Inhibitors

BACKGROUND

When treating patients with advanced non-small cell lung cancer (NSCLC) with tyrosine kinase inhibitors and chemotherapy, intercalated schedule with time separation between the two classes of drugs should avoid their mutual antagonism. In a survey of published trials, we focus on relation between eligibility criteria and effectiveness of intercalated treatment.

METHODS

Published documents were identified using major medical databases, conference proceedings and references of published trials. Median progression-free survival (PFS) was taken as the basic parameter of treatment efficacy. Correlation between characteristics of patients and median PFS was assessed through the Pearson's correlation coefficient and the coefficient of determination, separately for first-line and second-line setting.

RESULTS

The series includes 11 single-arm trials and 18 randomized phase II or phase III trials with a total of 2903 patients. Treatment-naive patients or those in progression after first-line treatment were included in 16 and 13 trials, respectively. In 14 trials, only patients with non-squamous histology were eligible. Proportion of patients with non-squamous carcinoma (in first-line setting), proportion of never-smokers (both in first- and second-line setting) and proportion of epidermal growth factor receptor (EGFR) mutant patients (both in first- and second-line setting) showed a moderate or strong correlation with median PFS. In six trials of intercalated treatment applied to treatment-naive EGFR-mutant patients, objective response was confirmed in 83.1% of cases and median PFS was 18.6 months.

CONCLUSIONS

Most suitable candidates for intercalated treatment are treatment-naive patients with EGFR-mutant tumors, as determined from biopsy or liquid biopsy. For these patients, experience with intercalated treatment is most promising and randomized trials with comparison to the best standard treatment are warranted.

Synchronous Duodenal Cancer and Lung Cancer Harboring an Epidermal Growth Factor Receptor Mutation Treated with Erlotinib and Oral Fluoropyrimidine

Chemotherapy for multiple primary cancers is challenging. We describe a case of synchronous duodenal cancer with lung cancer harboring an epidermal growth factor receptor (EGFR) mutation treated with erlotinib and S-1, an oral fluoropyrimidine agent. A 78-year-old woman with advanced EGFR-mutated lung adenocarcinoma was simultaneously diagnosed with duodenal adenocarcinoma. After the treatment with erlotinib, the lung cancer responded well, but her duodenal cancer showed no response. S-1 was added to erlotinib, and the duodenal cancer demonstrated a good response with tolerable toxicities. The concurrent use of erlotinib and S-1 was safe and efficacious for synchronous lung cancer harboring an EGFR mutation and duodenal cancer.

A Review of Regimens Combining Pemetrexed With an Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitor in the Treatment of Advanced Nonsquamous Non-Small-Cell Lung Cancer

Pemetrexed is a standard first-line treatment for advanced nonsquamous non-small-cell lung cancer (NSCLC), and epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) are a standard first-line treatment for advanced nonsquamous NSCLC with activating EGFR mutations. Pemetrexed and EGFR TKIs have different mechanisms of action and minimally overlapping toxicity profiles; therefore, it is hypothesized that their combination might result in acceptable toxicity, provided that the synergistic antitumor activity observed in preclinical studies is achieved. This review summarizes clinical trials of pemetrexed in combination with an EGFR TKI for the treatment of advanced nonsquamous NSCLC in the first- and second-line settings, using intercalated, sequential, and concurrent treatment strategies. As would be expected, such strategies were most efficacious in patients with the activating EGFR mutations associated with response to an EGFR TKI. In the studies that compared a pemetrexed-EGFR TKI combination with pemetrexed alone or the EGFR TKI alone, the pemetrexed-EGFR TKI combination was more efficacious than the single-agent regimens. The pemetrexed-EGFR TKI combinations were generally associated with a higher incidence of grade 3/4 treatment-related adverse events than the single-agent regimens; however, such toxicities were clinically manageable. Future studies of pemetrexed-EGFR TKI combinations should focus on optimizing treatment strategies in patients with activating EGFR mutations.

Combination of chemotherapy and gefitinib as first-line treatment for patients with advanced lung adenocarcinoma and sensitive EGFR mutations: A randomized controlled trial

To explore the optimal treatment strategy for patients who harbor sensitive EGFR mutations, a head-to-head study was performed to compare chemotherapy and gefitinib in combination or with either agent alone as first-line therapy, in terms of efficacy and safety. A total of 121 untreated patients with advanced lung adenocarcinoma who harbored sensitive EGFR mutations were randomly assigned to receive gefitinib combined with pemetrexed and carboplatin, pemetrexed plus carboplatin or gefitinib alone. The progression-free survival (PFS) of patients in the combination group (17.5 months, 95% CI, 15.3-19.7) was longer than that of patients in the chemotherapy group (5.7 months, 95% CI, 5.2-6.3) or gefitinib (11.9 months, 95% CI, 9.1-14.6) group. The (hazard ratios) HRs of PFS for the combination group vs. chemotherapy and gefitinib groups were 0.16 (95% CI, 0.09-0.29, p < 0.001) and 0.48 (95% CI, 0.29-0.78, p = 0.003), respectively. The overall response rate (ORR) in the combination therapy group, chemotherapy group and the gefitinib group was 82.5%, 32.5% and 65.9%, respectively. The combinational strategy resulted in longer overall survival (OS) than chemotherapy (HR = 0.46, p = 0.016) or gefitinib (HR = 0.36, p = 0.001) alone. Our finding suggested that treatment with pemetrexed plus carboplatin combined with gefitinib could provide better survival benefits for patients with lung adenocarcinoma harboring sensitive EGFR mutations.

Intercalated Chemotherapy and Epidermal Growth Factor Receptor Inhibitors for Patients With Advanced Non-Small-cell Lung Cancer: A Systematic Review and Meta-analysis

Randomized clinical trials (RCTs) of concurrent epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) plus chemotherapy for unselected patients with advanced non-small-cell lung cancer (NSCLC) produced negative results. Intercalated administration could avoid the reduction of chemotherapy activity due to G₁ cell-cycle arrest from EGFR-TKIs. A PubMed search was performed in December 2015 and updated in February 2016. The references from the selected studies were also checked to identify additional eligible trials. Furthermore, the proceedings of the main international meetings were searched from 2010 onward. We included RCTs comparing chemotherapy intercalated with an EGFR-TKI versus chemotherapy alone for patients with advanced NSCLC. Ten RCTs were eligible (6 with erlotinib, 4 with gefitinib): 39% of patients had a known EGFR mutational status, 43% of whom EGFR mutation positive. The intercalated combination was associated with a significant improvement in overall survival (OS; hazard ratio [HR], 0.82; 95% confidence interval [CI], 0.71-0.95; P = .01), progression-free survival (PFS; HR, 0.60; 95% CI, 0.53-0.68; P < .00001), and objective response rate (ORR; odds ratio [OR], 2.70; 95% CI, 2.08-3.49; P < .00001). Considering only first-line trials, similar differences were found in OS (HR, 0.85; 95% CI, 0.72-1.00; P = .05), PFS (HR, 0.63; 95% CI, 0.55-0.73; P < .00001), and ORR (OR, 2.21; 95% CI, 1.65-2.95; P < .00001). In EGFR mutation-positive patients, the addition of an intercalated EGFR-TKI produced a significant benefit in PFS (129 patients; HR, 0.24; 95% CI, 0.16-0.37; P < .00001) and ORR (168 patients; OR, 11.59; 95% CI, 5.54-24.25; P < .00001). In patients with advanced NSCLC, chemotherapy plus intercalated EGFR-TKIs was superior to chemotherapy alone, although a definitive interpretation was jeopardized by the variable proportion of patients with EGFR mutation-positive tumors included.

Randomized Phase II Trial of Gefitinib With and Without Pemetrexed as First-Line Therapy in Patients With Advanced Nonsquamous Non–Small-Cell Lung Cancer With Activating Epidermal Growth Factor Receptor Mutations

Purpose

To determine whether the addition of pemetrexed to gefitinib (P+G) provides clinical benefit, compared with gefitinib monotherapy, in patients with advanced nonsquamous (NS) non–small-cell lung cancer (NSCLC) and activating epidermal growth factor receptor (EGFR) mutations.

Patients and Methods

Chemotherapy-naïve for advanced NSCLC patients from China, Japan, Korea, and Taiwan (35 sites) with advanced, EGFR-mutant, NS NSCLC were randomly assigned (2:1; computer-generated, interactive voice response) to open-label pemetrexed (500 mg/m2 on day 1 of every 21-day cycle) plus gefitinib (250 mg/d [n = 129]) or gefitinib alone (n = 66). The primary end point was progression-free-survival (PFS); secondary end points were time to progressive disease, overall survival, tumor response rates, duration of response, and safety. All end points were assessed in the intent-to-treat and safety population (P+G, n = 126; gefitinib alone, n = 65).

Results

PFS was significantly longer with P+G (median, 15.8 months; 95% CI, 12.6 to 18.3 months) than with gefitinib (median, 10.9 months; 95% CI, 9.7 to 13.8 months; adjusted hazard ratio [HR], 0.68; 95% CI, 0.48 to 0.96; one-sided P = .014; two-sided P = .029). Results of EGFR exon 19 deletion and EGFR exon 21 L858R point mutation subgroup analyses were consistent with the intent-to-treat result. P+G, compared with gefitinib alone, resulted in significantly longer time to progressive disease (median, 16.2 v 10.9 months, respectively; HR, 0.66; 95% CI, 0.47 to 0.93) and numerically longer duration of response (median, 15.4 v 11.3 months, respectively; HR, 0.74; 95% CI, 0.50 to 1.08). Tumor response rates did not differ. Overall survival data are immature. Drug-related grade 3 or 4 adverse events were more common with P+G, but toxicities were manageable.

Conclusion

P+G improved PFS compared with gefitinib alone in East Asian patients with advanced NS NSCLC and activating EGFR mutations. This combination may offer EGFR mutation–positive patients new treatment options and improved clinical outcomes compared with the current standard of care.

The Efficacy of Bevacizumab in Different Line Chemotherapy for Chinese Patients with Metastatic Colorectal Cancer

Objective: To evaluate the effect of bevacizumab in different lines for Chinese patients with metastatic colorectal cancer (mCRC).

Methods: Patients of mCRC treated with bevacizumab or not at Sun Yat-sen University Cancer Center from 2007 to 2013 were recruited as study and control group. Endpoints were overall survival (OS), progression free survival (PFS), objective response rate (ORR) and disease control rate (DCR). Corresponding survival rates of first- and second-line in study and control group were compared.

Results: 1. Median OS of study and control group were 44.8 (95% CI: 37.1~52.4) months, 36.1 (95% CI: 32.8~39.5) months respectively, which were significantly different (P=0.004). 2. In the first line treatment, median OS of study and control group were 49.9(95% CI: 40.1~59.8) months and 36.1 (95% CI: 32.7~39.4) months (P=0.002), respectively. And median PFS were 10.1(95% CI: 8.7~11.5) months and 6.2 (95% CI: 5.5~6.8) months (P<0.001), respectively. 3. In the second line treatment, median OS of study and control group were 34.8 (95% CI: 26.3~43.3) months and 24.6 (95% CI: 22.2~27.0) months (P=0.022), respectively. And the mPFS were 6.3 (95% CI: 4.7~7.8) months and 3.1 (95% CI: 2.5~3.6) months (P<0.001), respectively. 4. Median OS of first- and second-line treatment of the study groups were 49.9(95% CI: 40.1~59.8) months and 34.8 (95% CI: 26.3~43.3) months (P=0.189), respectively.

Conclusion: The combination of bevacizumab and chemotherapy had a promising efficacy in Chinese mCRC patients. However, their OS were statistically insignificant between first- and second-line of bevacizumab groups.

Phase I Study of Oral Vinorelbine in Combination with Erlotinib in Advanced Non-Small Cell Lung Cancer (NSCLC) Using Two Different Schedules

Purpose

This study aimed to evaluate the safety, tolerability and pharmacokinetics of the combination of oral vinorelbine with erlotinib using the conventional (CSV) and metronomic (MSV) dosing schedules in patients with advanced non-small cell lung cancer (NSCLC).

Methods

This was an open-label, multiple dose-escalation phase I study. An alternating 3+3 phase I design was employed to allow each schedule to enroll three patients sequentially at each dose level. Thirty patients with Stage IIIB/IV NSCLC were treated with escalating doses of oral vinorelbine starting at 40 mg/m² on day 1 and 8 in the CSV group (N = 16) and at 100 mg/week in the MSV group (N = 14). Erlotinib was administered orally daily.

Results

The maximum tolerated dose was vinorelbine 80 mg/m² with erlotinib 100 mg in the CSV group and vinorelbine 120 mg/week with erlotinib 100 mg in the MSV group. Grade 3/4 toxicities included neutropenia (N = 2; 13%) and hyponatremia (N = 1; 6%) in the CSV group, and neutropenia (N = 5; 36%) in the MSV group. Objective response was achieved in 38% and 29% in the CSV and MSV groups respectively. Vinorelbine co-administration did not significantly affect the pharmacokinetics of erlotinib and OSI-420 after initial dose. However, at steady-state, significantly higher C_max, higher C_min and lower CL/F of erlotinib were observed with increasing dose levels of vinorelbine in the CSV group. Significantly higher steady-state C_min, C_avg and AUC_ss of erlotinib were observed with increasing dose levels of vinorelbine in the MSV group.

Conclusions

Combination of oral vinorelbine with erlotinib is feasible and tolerable in both the CSV and MSV groups.

Trial Registration

ClinicalTrials.gov NCT00702182

Combination of Gefitinib and Pemetrexed Prevents the Acquisition of TKI Resistance in NSCLC Cell Lines Carrying EGFR-Activating Mutation

INTRODUCTION

Development of resistance to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors is a clinical issue in patients with epidermal growth factor receptor gene (EGFR)-mutated non-small cell lung cancer (NSCLC). The aim of this study was to investigate the potential of combining gefitinib and pemetrexed in preventing the acquisition of resistance to EGFR tyrosine kinase inhibitors in NSCLC cell lines harboring EGFR exon 19 deletion.

METHODS

The effect of different combinatorial schedules of gefitinib and pemetrexed on cell proliferation, cell cycle, apoptosis, and acquisition of gefitinib resistance in PC9 and HCC827 NSCLC cell lines and in PC9 xenograft models was investigated.

RESULTS

Simultaneous treatment with gefitinib and pemetrexed enhanced cell growth inhibition and cell death and prevented the appearance of gefitinib resistance mediated by T790M mutation or epithelial-to-mesenchymal transition (EMT) in PC9 and HCC827 cells, respectively. In PC9 cells and in PC9 xenografts the combination of gefitinib and pemetrexed, with different schedules, prevented gefitinib resistance only when pemetrexed was the first treatment, given alone or together with gefitinib. Conversely, when gefitinib alone was administered first and pemetrexed sequentially alternated, a negative interaction was observed and no prevention of gefitinib resistance was documented. The mechanisms of resistance that developed in vivo included T790M mutation and EMT. The induction of EMT was a feature of tumors treated with gefitinib when given before pemetrexed, whereas T790M was recorded only in tumors treated with gefitinib alone.

CONCLUSIONS

The combination of gefitinib and pemetrexed is effective in preventing gefitinib resistance; the application of intermittent treatments requires that gefitinib not be administered before pemetrexed.