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

Patients with non‑small cell lung cancer with the exon 21 L858R mutation: From distinct mechanisms to epidermal growth factor receptor tyrosine kinase inhibitor treatments (Review)

The most common oncogenic driver in non-small cell lung cancer (NSCLC) is epidermal growth factor receptor (EGFR) gene mutations, which are more common in Asian (30-50%) than in Caucasian (10-15%) populations. Exon 19 deletion (ex19del) and exon 21 L858R (ex21 L858R) mutations account for ~45 and 40% of all EGFR mutations, respectively. Moreover, EGFR-tyrosine kinase inhibitors (TKIs) may be more effective and improve the quality of life of patients with NSCLC more than chemotherapy regimens. By contrast, patients with the ex21 L858R mutation may have a lower sensitivity and duration of response to EGFR-TKIs as well as a shorter survival compared with those with the ex19del mutation. However, current guidelines classify ex21 L858R and ex19del as the same condition and recommend the same treatment strategy for both. Aiming for precision medicine, the present review introduces and compares different EGFR-TKIs for the ex21 L858R mutation to assess more personalized treatment options for the population with this mutation.

A Bayesian network meta-analysis of EGFR-tyrosine kinase inhibitor treatments in patients with EGFR mutation-positive non-small cell lung cancer

Background

To date, no direct comparisons have been performed to compare the effectiveness of all epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) against EGFR mutation-positive non-small cell lung cancer (NSCLC). This study aimed to investigate the efficacy and safety of EGFR-TKIs in patients with EGFR mutation-positive NSCLC.

Methods

We conducted a network meta-analysis of randomized controlled trials comparing osimertinib, lazertinib, aumolertinib, befotertinib, furmonertinib, dacomitinib, afatinib, erlotinib, gefitinib, icotinib, and chemotherapy. Pooled estimations of progression-free survival (PFS), overall survival (OS), objective response rate (ORR), and toxicity (grade ≥ 3 adverse events) were performed within the Bayesian framework.

Results

Twenty-three trials involving 11 treatments were included. All EGFR-TKIs improved PFS relative to chemotherapy, except for icotinib (hazard ratio [HR] = 0.61, 95% confidence interval [CI]: 0.26-1.44). All EGFR-TKIs demonstrated significant ORR benefits over chemotherapy. Osimertinib seemed to prolong PFS compared with icotinib (HR = 0.29, 95% CI: 0.1-0.86), gefitinib (HR = 0.39, 95% CI: 0.21-0.74), and erlotinib (HR = 0.53, 95% CI: 0.29-1.0). In addition, osimertinib showed favorable superiority in improving OS compared with chemotherapy (HR = 0.6, 95% CI: 0.43-0.82), gefitinib (HR = 0.61, 95% CI: 0.45-0.83), erlotinib (HR = 0.65, 95% CI: 0.48-0.89), and afatinib (HR = 0.65, 95% CI: 0.44-0.94). Among these regimens, afatinib showed the highest ORR (cumulative probability: 96.96%). Icotinib was associated with minimal toxicity among the EGFR-TKIs, followed by furmonertinib and osimertinib. Moreover, the toxicity spectra differed among the EGFR-TKIs. Subgroup analyses of patients with two common types of EGFR mutations indicated that furmonertinib possessed the greatest PFS benefit in patients with exon 19 deletion, and lazertinib showed the greatest PFS benefit in patients with Leu858Arg mutation. We also identified differences between EGFR-TKIs in prolonging PFS in patients with brain metastasis.

Conclusions

Osimertinib is the first choice of treatment with considerable efficacy and safety for EGFR mutation-positive NSCLC. The treatments associated with the best PFS in patients with exon 19 deletions and Leu858Arg mutations were furmonertinib and lazertinib, respectively.

The changing treatment landscape of EGFR-mutant non-small-cell lung cancer

The discovery of the association between EGFR mutations and the efficacy of EGFR tyrosine-kinase inhibitors (TKIs) has revolutionized the treatment paradigm for patients with non-small-cell lung cancer (NSCLC). Currently, third-generation EGFR TKIs, which are often characterized by potent central nervous system penetrance, are the standard-of-care first-line treatment for advanced-stage EGFR-mutant NSCLC. Rational combinations of third-generation EGFR TKIs with anti-angiogenic drugs, chemotherapy, the EGFR-MET bispecific antibody amivantamab or local tumour ablation are being investigated as strategies to delay drug resistance and increase clinical benefit. Furthermore, EGFR TKIs are being evaluated in patients with early stage or locally advanced EGFR-mutant NSCLC, with the ambitious aim of achieving cancer cure. Despite the inevitable challenge of acquired resistance, emerging treatments such as new TKIs, antibody-drug conjugates, new immunotherapeutic approaches and targeted protein degraders have shown considerable promise in patients with progression of EGFR-mutant NSCLC on or after treatment with EGFR TKIs. In this Review, we describe the current first-line treatment options for EGFR-mutant NSCLC, provide an overview of the mechanisms of acquired resistance to third-generation EGFR TKIs and explore novel promising treatment strategies. We also highlight potential avenues for future research that are aimed at improving the survival outcomes of patients with this disease.

What is the optimal first-line regimen for advanced non-small cell lung cancer patients with epidermal growth factor receptor mutation: a systematic review and network meta-analysis

OBJECTIVES

There are currently various tyrosine kinase inhibitor (TKI)-based regimens available, and it can be challenging for clinicians to determine the most effective and safe option due to the lack of direct comparisons between these regimens. In this study, we conducted a network meta-analysis comparing the efficacy and safety of distinct regimens to determine the optimal regimen for patients with EGFR-mutated non-small cell lung cancer, thereby facilitating clinical decision-making.

MATERIALS AND METHODS

The PubMed, Embase, Cochrane Library databases and international conference databases were comprehensively searched from their inception to 02 April 2024 for collecting data regarding efficacy and safety from eligible randomized controlled trials (RCTs). Following literature screening and data extraction, a NMA was conducted to compare the efficacy and safety among 21 regimens with a random-effects consistency model in a Bayesian framework using a Markov Chain Monte Carlo simulation technique within the GEMTC package.

RESULTS

A total of 35 RCTs were included, involving 9718 individuals and 21 regimens. Compared with other interventions, combination therapies based on third-generation TKIs, especially osimertinib plus ramucirumab, showed the most favorable PFS prolongation in overall patients. Consistently, subgroup analyses showed that third-generation TKIs-based combination regimens were superior to other regimens in most prespecified subgroups with distinct clinicopathological characteristics. In terms of overall survival, despite the combination regimens based on third-generation TKIs also showing relatively superior outcomes, erlotinib plus chemotherapy and gefitinib plus chemotherapy were ranked more favorably. In terms of safety profile, combination therapies based on third-generation TKIs did not significantly increase the incidence of grade 3 or higher adverse events compared with other regimens.

CONCLUSION

Our study concluded that combination regimens based on third-generation TKIs (osimertinib plus ramucirumab, osimertinib plus chemotherapy, osimertinib plus bevacizumab, amivantamab plus lazertinib and aumolertinib plus apatinib) could be the new and clinically preferable first-line, standard of care for EGFR-mutated advanced non-small cell lung cancer.

TRIAL REGISTRATION

The protocol was registered in the Prospective Register of Systematic Reviews (PROSPERO CRD42023480596).

EGFR-TKIs or EGFR-TKIs combination treatments for untreated advanced EGFR-mutated NSCLC: a network meta-analysis

BACKGROUND

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) and EGFR-TKI combination treatments have become the standard first-line treatments for EGFR-mutated non-small cell lung cancer (NSCLC) patients. However, the best option has yet to be determined. This study compares the efficacy and safety of various first-line EGFR-TKI monotherapies and combination treatments for advanced EGFR-mutated NSCLC.

METHODS

We searched PubMed, Embase, the Cochrane Central Register of Controlled Clinical Trials databases, and several international conferences to identify randomized controlled trials reporting on first-line EGFR-TKI treatments for patients with advanced EGFR-mutated NSCLC. The study quality was assessed using the revised tool for risk of bias in randomized trials. The efficacy and safety outcomes of the included treatments were compared by network meta-analysis based on a frequentist approach.

RESULTS

We identified 26 trials (8,359 patients) investigating 14 treatment groups, including first, second, and third-generation EGFR-TKIs and their combination treatments. Osimertinib plus chemotherapy and lazertinib plus amivantamab showed the highest efficacy in improving progression-free survival. New third-generation EGFR-TKIs demonstrated comparable efficacy to osimertinib alone but did not surpass it. Subgroup analyses revealed slight variation in treatment efficacy based on mutation types and patient demographics. Combination treatments were associated with a higher incidence of adverse events.

CONCLUSION

These results reveal that osimertinib plus chemotherapy and lazertinib plus amivantamab are superior first-line options for patients with advanced EGFR-mutated NSCLC. However, these combinations are associated with higher adverse event rates.

The benefit and risk of addition of chemotherapy to EGFR tyrosine kinase inhibitors for EGFR-positive non-small cell lung cancer patients with brain metastases: a meta-analysis based on randomized controlled trials

Background

Combining epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) with chemotherapy (ETC) offers more advantages for patients with EGFR-positive non-small cell lung cancer (NSCLC) than using EGFR TKIs alone (ET). However, whether this conclusion applies to patients with brain metastases (BM) remains controversial. This meta-analysis was performed to evaluate the benefits and risks of the two groups.

Methods

Six databases were systematically searched for relevant literatures comparing ETC versus ET in treating EGFR-positive NSCLC patients with BM. The primary outcome assessed was overall survival (OS), while secondary outcomes included progression-free survival (PFS), and central nervous system (CNS)-PFS, responses, progression status and safety.

Results

Seven studies based on five randomized clinical trials with 550 patients were included. The ETC group exhibited better OS (hazard ratio [HR]: 0.64 [0.48, 0.87]), PFS (HR: 0.42 [0.34, 0.52]), and CNS-PFS (HR: 0.42 [0.31, 0.57]). The benefits in survival for OS, PFS, and CNS-PFS were validated in nearly all subgroups. Meanwhile, the overall objective response rate (ORR) (risk ratio [RR]: 1.25 [1.02, 1.52]) and CNS-ORR (RR: 1.19 [0.93, 1.51]) also tended to favor the ETC group. However, the addition of chemotherapy also brought about more grade 3-5/serious adverse events (AEs). The top five grade 3-5 AEs in the ETC group were alanine aminotransferase increase (11.25%), neutropenia (7.5%), nausea (7.5%), anorexia (5%), and diarrhea (5%).

Conclusions

ETC appears to be better than ET in treating EGFR-positive NSCLC patients with BM, with better OS, PFS, CNS-PFS, and responses. However, its poorer safety profile also needs to be taken into consideration.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42024551073.

Targeting metabolic adaptive responses induced by glucose starvation inhibits cell proliferation and enhances cell death in osimertinib-resistant non-small cell lung cancer (NSCLC) cell lines

Osimertinib, a tyrosine kinase inhibitor targeting mutant EGFR, has received approval for initial treatment in patients with Non-Small Cell Lung Cancer (NSCLC). While effective in both first- and second-line treatments, patients eventually develop acquired resistance. Metabolic reprogramming represents a strategy through which cancer cells may resist and adapt to the selective pressure exerted by the drug. In the current study, we investigated the metabolic adaptations associated with osimertinib-resistance in NSCLC cells under low glucose culture conditions. We demonstrated that, unlike osimertinib-sensitive cells, osimertinib-resistant cells were able to survive under low glucose conditions by increasing the rate of glucose and glutamine uptake and by shifting towards mitochondrial metabolism. Inhibiting glucose/pyruvate contribution to mitochondrial respiration, glutamine deamination to glutamate, and oxidative phosphorylation decreased the proliferation and survival abilities of osimertinib-resistant cells to glucose starvation. Our findings underscore the remarkable adaptability of osimertinib-resistant NSCLC cells in a low glucose environment and highlight the pivotal role of mitochondrial metabolism in mediating this adaptation. Targeting the metabolic adaptive responses triggered by glucose shortage emerges as a promising strategy, effectively inhibiting cell proliferation and promoting cell death in osimertinib-resistant cells.

Phosphorylation of AGO2 by TBK1 Promotes the Formation of Oncogenic miRISC in NSCLC

Non-small-cell lung cancer (NSCLC) is a highly lethal tumor that often develops resistance to targeted therapy. It is shown that Tank-binding kinase 1 (TBK1) phosphorylates AGO2 at S417 (pS417-AGO2), which promotes NSCLC progression by increasing the formation of microRNA-induced silencing complex (miRISC). High levels of pS417-AGO2 in clinical NSCLC specimens are positively associated with poor prognosis. Interestingly, the treatment with EGFR inhibitor Gefitinib can significantly induce pS417-AGO2, thereby increasing the formation and activity of oncogenic miRISC, which may contribute to NSCLC resistance to Gefitinib. Based on these, two therapeutic strategies is developed. One is jointly to antagonize multiple oncogenic miRNAs highly expressed in NSCLC and use TBK1 inhibitor Amlexanox reducing the formation of oncogenic miRISC. Another approach is to combine Gefitinib with Amlexanox to inhibit the progression of Gefitinib-resistant NSCLC. This findings reveal a novel mechanism of oncogenic miRISC regulation by TBK1-mediated pS417-AGO2 and suggest potential therapeutic approaches for NSCLC.

Tumor-associated macrophages in non-small-cell lung cancer: From treatment resistance mechanisms to therapeutic targets

Non-small cell lung cancer (NSCLC) remains one of the leading causes of cancer-related deaths worldwide. Different treatment approaches are typically employed based on the stage of NSCLC. Common clinical treatment methods include surgical resection, drug therapy, and radiation therapy. However, with the introduction and utilization of immune checkpoint inhibitors, cancer treatment has entered a new era, completely revolutionizing the treatment landscape for various cancers and significantly improving overall patient survival. Concurrently, treatment resistance often poses a critical challenge, with many patients experiencing disease progression following an initial response due to treatment resistance. Increasing evidence suggests that the tumor microenvironment (TME) plays a pivotal role in treatment resistance. Tumor-associated macrophages (TAMs) within the TME can promote treatment resistance in NSCLC by secreting various cytokines activating signaling pathways, and interacting with other immune cells. Therefore, this article will focus on elucidating the key mechanisms of TAMs in treatment resistance and analyze how targeting TAMs can reduce the levels of treatment resistance in NSCLC, providing a comprehensive understanding of the principles and approaches to overcome treatment resistance in NSCLC.

Targeting glucosylceramide synthase induces antiproliferative and proapoptotic effects in osimertinib-resistant NSCLC cell models

The EGFR tyrosine kinase inhibitor osimertinib has been approved for the first-line treatment of EGFR-mutated Non-Small Cell Lung Cancer (NSCLC) patients. Despite its efficacy, patients develop resistance. Mechanisms of resistance are heterogeneous and not fully understood, and their characterization is essential to find new strategies to overcome resistance. Ceramides are well-known regulators of apoptosis and are converted into glucosylceramides (GlcCer) by glucosylceramide synthase (GCS). A higher content of GlcCers was observed in lung pleural effusions from NSCLC patients and their role in osimertinib-resistance has not been documented. The aim of this study was to determine the therapeutic potential of inhibiting GCS in NSCLC EGFR-mutant models resistant to osimertinib in vitro and in vivo. Lipidomic analysis showed a significant increase in the intracellular levels of glycosylceramides, including GlcCers in osimertinib resistant clones compared to sensitive cells. In resistant cells, the GCS inhibitor PDMP caused cell cycle arrest, inhibition of 2D and 3D cell proliferation, colony formation and migration capability, and apoptosis induction. The intratumoral injection of PDMP completely suppressed the growth of OR xenograft models. This study demonstrated that dysregulation of ceramide metabolism is involved in osimertinib-resistance and targeting GCS may be a promising therapeutic strategy for patients progressed to osimertinib.

Front-line therapy for brain metastases and non-brain metastases in advanced epidermal growth factor receptor-mutated non-small cell lung cancer: a network meta-analysis

BACKGROUND

The brain is a common metastatic site in patients with non-small cell lung cancer (NSCLC), resulting in a relatively poor prognosis. Systemic therapy with epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) is recommended as the first-line treatment for EGFR -mutated, advanced NSCLC patients. However, intracranial activity varies in different drugs. Thus, brain metastasis (BM) should be considered when choosing the treatment regimens. We conducted this network meta-analysis to explore the optimal first-line therapeutic schedule for advanced EGFR -mutated NSCLC patients with different BM statuses.

METHODS

Randomized controlled trials focusing on EGFR-TKIs (alone or in combination) in advanced and EGFR -mutant NSCLC patients, who have not received systematic treatment, were systematically searched up to December 2021. We extracted and analyzed progression-free survival (PFS) and overall survival (OS). A network meta-analysis was performed with the Bayesian statistical model to determine the survival outcomes of all included therapy regimens using the R software. Hazard ratios (HRs) and 95% confidence intervals (CIs) were used to compare intervention measures, and overall rankings of therapies were estimated under the Bayesian framework.

RESULTS

This analysis included 17 RCTs with 5077 patients and 12 therapies, including osimertinib + bevacizumab, aumolertinib, osimertinib, afatinib, dacomitinib, standards of care (SoC, including gefitinib, erlotinib, or icotinib), SoC + apatinib, SoC + bevacizumab, SoC + ramucirumab, SoC + pemetrexed based chemotherapy (PbCT), PbCT, and pemetrexed free chemotherapy (PfCT). For patients with BM, SoC + PbCT improved PFS compared with SoC (HR = 0.40, 95% CI: 0.17-0.95), and osimertinib + bevacizumab was most likely to rank first in PFS, with a cumulative probability of 34.5%, followed by aumolertinib, with a cumulative probability of 28.3%. For patients without BM, osimertinib + bevacizumab, osimertinib, aumolertinib, SoC + PbCT, dacomitinib, SoC + ramucirumab, SoC + bevacizumab, and afatinib showed superior efficacy compared with SoC (HR = 0.43, 95% CI: 0.20-0.90; HR = 0.46, 95% CI: 0.31-0.68; HR = 0.51, 95% CI: 0.34-0.77; HR = 0.50, 95% CI: 0.38-0.66; HR = 0.62, 95% CI: 0.43-0.89; HR = 0.64, 95% CI: 0.44-0.94; HR = 0.61, 95% CI: 0.48-0.76; HR = 0.71, 95% CI: 0.50-1.00), PbCT (HR = 0.29, 95% CI: 0.11-0.74; HR = 0.31, 95% CI: 0.15-0.62; HR = 0.34, 95% CI: 0.17-0.69; HR = 0.34, 95% CI: 0.18-0.64; HR = 0.42, 95% CI: 0.21-0.82; HR = 0.43, 95% CI: 0.22-0.87; HR = 0.41, 95% CI: 0.22-0.74; HR = 0.48, 95% CI: 0.31-0.75), and PfCT (HR = 0.14, 95% CI: 0.06-0.32; HR = 0.15, 95% CI: 0.09-0.26; HR = 0.17, 95% CI: 0.09-0.29; HR = 0.16, 95% CI: 0.10-0.26; HR = 0.20, 95% CI: 0.12-0.35; HR = 0.21, 95% CI: 0.12-0.39; HR = 0.20, 95% CI: 0.12-0.31; HR = 0.23, 95% CI: 0.16-0.34) in terms of PFS. And, SoC + apatinib showed relatively superior PFS when compared with PbCT (HR = 0.44, 95% CI: 0.22-0.92) and PfCT (HR = 0.21, 95% CI: 0.12-0.39), but similar PFS to SoC (HR = 0.65, 95% CI: 0.42-1.03). No statistical differences were observed for PFS in patients without BM between PbCT and SoC (HR = 1.49, 95% CI: 0.84-2.64), but both showed favorable PFS when compared with PfCT (PfCT vs. SoC, HR = 3.09, 95% CI: 2.06-4.55; PbCT vs. PfCT, HR = 0.14, 95% CI: 0.06-0.32). For patients without BM, osimertinib + bevacizumab was most likely to rank the first, with cumulative probabilities of 47.1%. For OS, SoC + PbCT was most likely to rank first in patients with and without BM, with cumulative probabilities of 46.8%, and 37.3%, respectively.

CONCLUSION

Osimertinib + bevacizumab is most likely to rank first in PFS in advanced EGFR -mutated NSCLC patients with or without BM, and SoC + PbCT is most likely to rank first in OS.

A New ABCB1 Inhibitor Enhances the Anticancer Effect of Doxorubicin in Both In Vitro and In Vivo Models of NSCLC

In tumors, the multi drug resistance phenomenon may occur through the efflux of chemotherapeutic drugs out of cancer cells, impeding their accumulation, and eventually reducing their toxicity. This process is mediated by transporters overexpressed in the plasma membranes of tumor cells, among which is the P-glycoprotein/multidrug resistance 1/ATP-binding cassette B1 (P-gp/MDR1/ABCB1). The aim of this study was to explore the effect of a new molecule, called AIF-1, on ABCB1 activity. In a cellular model of non-small cell lung cancer (NSCLC), AIF-1 significantly inhibited ABCB1 activity, which was evaluated by the fluorimetric measurement of the intracellular accumulation of calcein. AIF-1 also significantly increased the intracellular content of doxorubicin, which was evaluated by confocal microscopy and LC-MS/MS analysis. This effect translated to higher cytotoxicity of doxorubicin and reduced cellular proliferation. Finally, in a murine xenograft model, the tumor volume increased by 267% and 148% on average in mice treated with vehicle and doxorubicin alone, respectively. After the co-administration of doxorubicin with AIF-1, tumor volume increased by only 13.4%. In conclusion, these results suggest enhancement of the efficacy of the chemotherapeutic drug doxorubicin by AIF-1, laying the basis for the future development of new ABCB1 inhibitors for tumor treatment.

Comparison of gefitinib plus chemotherapy versus gefitinib alone for advanced non‑small‑cell lung cancer: A meta analysis

This study aimed to perform a meta‑analysis comparing the efficacy and safety of gefitinib in combination with chemotherapy versus gefitinib alone in patients with advanced Non‑Small Cell Lung Cancer (NSCLC). We searched databases for clinical studies that reported the efficacy or safety of gefitinib plus chemotherapy in comparison with gefitinib alone. Raw data from included studies were extracted and pooled to calculate the Odds Ratio (OR) for Objective Response Rate (ORR) and Disease Control Rate (DCR), the Hazard Ratio (HR) for Progression-Free Survival (PFS) and Overall Survival (OS), and OR for complication ≥ Grade 3. A total of 10 studies containing 1,528 patients with NSCLC were identified and included in the analysis. Gefitinib plus chemotherapy showed significantly better efficacy in improving ORR (OR = 1.54; 95% CI [Confidence Interval], 1.13‒2.1; p = 0.006), DCR (OR = 1.62; 95% CI 1.14‒2.29; p = 0.007), PFS (HR=1.67; 95% CI 1.45‒1.94; p < 0.001) and OS (HR = 1.49; 95% CI 1.2‒1.87; p < 0.001) as compared with gefitinib alone. Consistent results were observed in the sub-population with positive EGFR mutation. The combination of gefitinib with chemotherapy had a significantly higher risk of complication (≥ Grade 3) with an OR of 3.29 (95% CI 2.57‒4.21; p < 0.001). The findings in the present study suggest that the combination of gefitinib with chemotherapy can provide better disease response and survival outcomes for patients with advanced NSCLC.

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.

Comparison of the efficacy and safety of first-line treatments based on clinicopathological characteristics for patients with advanced epidermal growth factor receptor mutated non-small-cell lung cancer: A systematic review and network meta-analysis

BACKGROUND

A growing number of regimens have been approved as first-line treatments for patients with advanced epidermal growth factor receptor (EGFR) mutated non-small cell lung cancer. However, the optimal regimen has not been determined, especially for patients with different clinicopathological characteristics. Therefore, we performed this meta-analysis to compare the efficacy and safety of first-line treatments for patients with EGFR-mutated NSCLC based on clinicopathological characteristics, thereby providing evidence for individual patient clinical decision-making.

METHODS

The PubMed, Embase, Cochrane Library databases, and abstracts of ASCO, ESMO, and WCLC were searched from inception to 3 June 2021 to identify eligible randomized controlled trials (RCTs). The outcomes of progression-free survival (PFS), overall survival (OS), objective response rate (ORR), and grade 3 or higher adverse events (≥3AEs) were compared and ranked based on various clinicopathological characteristics among 14 regimens by network meta-analysis (NMA) and the surface under the cumulative ranking curve (SUCRA), respectively.

RESULTS

25 RCTs were included, with a total of 6965 patients and 14 treatment regimens. The primary endpoint of all RCTs was PFS, and OS, ORR, and ≥3AEs were secondary endpoints. Regarding overall patients, the most distinct PFS benefit was observed in osimertinib (OSI), with the fewest ≥3AEs, whereas gefitinib plus pemetrexed-based chemotherapy (GEF+PB) provided the greatest benefit for OS. When considering EGFR mutation type, aumolertinib (AUM) and GEF+PB could be the optimal regimens in terms of PFS for patients with EGFR 19DEL and EGFR 21L858R, respectively. Notably, the efficacy of the 14 regimens for PFS varied across clinicopathological characteristics, with GEP+PB ranking first in Eastern Cooperative Oncology Group performance status (ECOG PS)= 1, Asian, age＜65 and smoking subgroups, with AUM ranking first in ECOG PS= 0 and female subgroups, with ICO+PB ranking first in age ≥65 and no smoking subgroups, and with AFA+CET ranking first in the male subgroup. In terms of brain metastases, third-generation EGFR-TKI showed obvious superiority, with AUM and OSI optimally prolonging PFS in patients with and without brain metastases, respectively. In addition, GEF+PB is a superior alternative, ranking second in terms of PFS regardless of the presence of brain metastases.

CONCLUSIONS

OSI and GEF+PB were the most two effective first-line regimens for overall patients, ranking first in PFS and OS, respectively. GEF+PB ranked first in terms of PFS in subgroups of EGFR 21L858R, ECOG PS= 1, Asian, age <65, and smoking. Meanwhile, AUM in subgroups of EGFR 19DEL, ECOG PS= 0, female, brain metastasis, OSI in the subgroup of without brain metastasis, ICO+PB in no smoking subgroup, and AFA+CET in male subgroup were the best options as for their evident superiority in PFS.

Overall Survival Benefits of First-Line Treatments for Asian Patients with Advanced Epidermal Growth Factor Receptor-Mutated NSCLC Harboring Exon 19 Deletion: A Systematic Review and Network Meta-Analysis

Simple Summary

Survival benefits and clinical responsiveness have been exhibited by various generations of EGFR-tyrosine kinase inhibitors (TKIs) in numerous randomized-controlled trials for EGFR-mutated advanced non-small-cell lung cancer (NSCLC) over the past two decades. However, the efficacy, especially long-term overall survival (OS) for Asians harboring an exon 19 deletion (19del) in their NSCLC, remains uncertain. This systematic review and network meta-analysis evaluate the efficacy of all first-line treatments in Asian patients with advanced EGFR-mutated NSCLC harboring 19del. EGFR-TKIs and combination treatments demonstrated no OS benefits in comparison with standard chemotherapy treatments, although progression-free survival (PFS) benefits were revealed. Erlotinib plus bevacizumab, ramucirumab plus erlotinib, and osimertinib are the optimal regimens to prolong PFS for Asians with 19del. Further studies are warranted to investigate the resistance mechanisms and possible strategies for individuals harboring this common mutation.

Abstract

(1) Background: Randomized controlled trials (RCTs) have explored various primary treatments for individuals diagnosed as having later-stage epidermal growth factor receptor (EGFR)-mutated non-small-cell lung cancer. Nevertheless, the extent to which such treatments are efficacious, particularly with regard to overall survival (OS) rates of patients from Asia with exon 19 deletion (19del), has yet to be clarified. (2) Methods: A systematic review and frequentist network meta-analysis were conducted by obtaining pertinent studies from PubMed/MEDLINE Ovid, Embase, Cochrane Library, and trial registries, as well as various other sources. RCTs in which two or multiple treatments in the primary setting for patients from Asia with EGFR 19del were compared were included. This research has been recorded in the Prospective Register of Systematic Reviews (CRD 42022320833). (3) Results: A total of 2715 patients from Asia participated in 18 trials in which 12 different treatments were administered, which included: EGFR tyrosine kinase inhibitors (TKIs) (osimertinib, dacomitinib, afatinib, erlotinib, gefitinib, and icotinib), pemetrexed-based chemotherapy, pemetrexed-free chemotherapy, and combination treatments (gefitinib plus apatinib, erlotinib plus ramucirumab, erlotinib plus bevacizumab, and gefitinib plus pemetrexed-based chemotherapy). Such treatments were not significantly beneficial in terms of OS for patients from Asia who had 19del. It was demonstrated that erlotinib plus bevacizumab, ramucirumab plus erlotinib, and osimertinib consistently yielded the greatest benefits regarding progression-free survival benefit (P-scores = 94%, 84%, and 80%, respectively). Combination treatments resulted in increased toxicity, particularly gefitinib plus apatinib and erlotinib plus bevacizumab, causing the highest prevalence of grade ≥ 3 adverse events. Icotinib and osimertinib had the fewest grade ≥ 3 adverse events. Specific treatments were associated with a wide range of toxicity levels. (4) Conclusions: In patients from Asia with 19del, both EGFR-TKIs and treatments in which therapies were combined exhibited no OS benefits in comparison with standard chemotherapy treatments. Additional research is required to study TKIs’ resistance mechanisms and possible combined approaches for individuals harboring this common mutation.

Combination Effect of Cilengitide with Erlotinib on TGF-β1-Induced Epithelial-to-Mesenchymal Transition in Human Non-Small Cell Lung Cancer Cells

The epithelial-to-mesenchymal transition (EMT) is important for morphogenesis during development and is mainly induced by transforming growth factor (TGF)-β. In lung cancer, EMT is characterized by the transformation of cancer cells into a mobile, invasive form that can transit to other organs. Here, using a non–small cell lung cancer (NSCLC) cell line, we evaluated the EMT-related effects of the epidermal growth factor receptor inhibitor erlotinib alone and in combination with cilengitide, a cyclic RGD-based integrin antagonist. Erlotinib showed anti-proliferative and inhibitory effects against the TGF-β1–induced EMT phenotype in NSCLC cells. Compared with erlotinib alone, combination treatment with cilengitide led to an enhanced inhibitory effect on TGF-β1–induced expression of mesenchymal markers and invasion in non–small cell lung cancer A549 cells. These results suggest that cilengitide could improve anticancer drug efficacy and contribute to improved treatment strategies to inhibit and prevent EMT-based cancer progression.

Front-Line Therapy in EGFR Exon 19 Deletion and 21 Leu858Arg Mutations in Advanced Non-Small Cell Lung Cancer: A Network Meta-Analysis

Objective

This study aimed to compare the efficacy of different first-line strategies based on different EGFR mutation types (19 deletion and 21 Leu858Arg mutations).

Methods

We conducted a systematic review and network meta-analysis (NMA) by searching and analyzing RCTs on PubMed, Embase, Cochrane Library, ASCO.org, and ESMO.org, from inception to September 30^th, 2020.

Results

Nineteen RCTs involving 5450 patients were finally included in this study, covering 10 different treatment strategies. The Bayesian ranking results suggested that, in terms of PFS, in the overall population and in patients with 19del mutation, osimertinib was most likely to rank the first, with the cumulative probabilities of 41.89% and 45.73%, respectively, while for patients with 21 Leu858Arg mutation, standard of care (SoC, represents first-generation EGFR-TKIs in this NMA) + chemotherapy was most likely to rank the first, with the cumulative probabilities of 30.81% in PFS. Moreover, SoC + chemotherapy provided the best overall survival benefit for the overall population and patients with 19del, with the cumulative probabilities of 57.85% and 33.51%, respectively. In contrast, for patients with 21 Leu858Arg mutation, dacomitinib showed the most favorable overall survival, with the cumulative probabilities of 36.73%.

Conclusions

In this NMA, osimertinib and SoC combined with chemotherapy would be the optimal first-line treatment options for advanced NSCLC patients harboring EGFR 19 deletion mutation and 21 Leu858Arg mutation, respectively. This finding is likely to be adopted in clinical practice and provide guidance for future clinical study design. Systematic review registration: INPLASY2020100059.

ELF3 Is a Target That Promotes Therapeutic Efficiency in EGFR Tyrosine Kinase Inhibitor-Resistant Non-Small Cell Lung Cancer Cells via Inhibiting PKCί

(1) Background: Mutations in epidermal growth factor receptor (EGFR) proteins account for many non-small cell lung cancers (NSCLCs), and EGFR tyrosine kinase inhibitors (TKIs) are being used as targeted therapeutics. However, resistance to TKIs continues to increase owing to additional mutations in more than half of the patients receiving EGFR TKI therapy. In addition to targeting new mutations with next-generation therapeutics, it is necessary to find an alternative target to overcome the challenges associated with resistance. (2) Methods: To identify potential alternative targets in patients with NSCLC undergoing targeted therapy, putative targets were identified by transcriptome profiling and validated for their biological and therapeutic effects in vitro and in vivo. (3) Results: ELF3 was found to be differentially expressed in NSCLC, and ELF3 knockdown significantly increased cell death in K-Ras mutant as well as in EGFR L858R/T790M mutation harboring lung cancer cells. We also found that auranofin, an inhibitor of protein kinase C iota (PKCί), a protein upstream of ELF3, effectively induced cell death. (4) Conclusions: Our study suggests that blocking ELF3 is an effective way to induce cell death in NSCLC with K-Ras and EGFR T790M/L858R mutations and thus advocates the use of auranofin as an effective alternative drug to overcome EGFR TKI resistance.

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.

Targeting the Epidermal Growth Factor Receptor in EGFR-Mutated Lung Cancer: Current and Emerging Therapies

Epidermal growth factor receptor-targeting tyrosine kinase inhibitors (EGFR TKIs) are the standard of care for patients with EGFR-mutated metastatic lung cancer. While EGFR TKIs have initially high response rates, inherent and acquired resistance constitute a major challenge to the longitudinal treatment. Ongoing work is aimed at understanding the molecular basis of these resistance mechanisms, with exciting new studies evaluating novel agents and combination therapies to improve control of tumors with all forms of EGFR mutation. In this review, we first provide a discussion of EGFR-mutated lung cancer and the efficacy of available EGFR TKIs in the clinical setting against both common and rare EGFR mutations. Second, we discuss common resistance mechanisms that lead to therapy failure during treatment with EGFR TKIs. Third, we review novel approaches aimed at improving outcomes and overcoming resistance to EGFR TKIs. Finally, we highlight recent breakthroughs in the use of EGFR TKIs in non-metastatic EGFR-mutated lung cancer.

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.

EGFR mutation mediates resistance to EGFR tyrosine kinase inhibitors in NSCLC: From molecular mechanisms to clinical research

With the development of precision medicine, molecular targeted therapy has been widely used in the field of cancer, especially in non-small-cell lung cancer (NSCLC). Epidermal growth factor receptor (EGFR) is a well-recognized and effective target for NSCLC therapies, targeted EGFR therapy with EGFR-tyrosine kinase inhibitors (EGFR-TKIs) has achieved ideal clinical efficacy in recent years. Unfortunately, resistance to EGFR-TKIs inevitably occurs due to various mechanisms after a period of therapy. EGFR mutations, such as T790M and C797S, are the most common mechanism of EGFR-TKI resistance. Here, we discuss the mechanisms of EGFR-TKIs resistance induced by secondary EGFR mutations, highlight the development of targeted drugs to overcome EGFR mutation-mediated resistance, and predict the promising directions for development of novel candidates.

Cyclic RGD Pentapeptide Cilengitide Enhances Efficacy of Gefitinib on TGF-β1-Induced Epithelial-to-Mesenchymal Transition and Invasion in Human Non-Small Cell Lung Cancer Cells

During non-small cell lung cancer (NSCLC) progression, transforming growth factor (TGF)-β mediated epithelial-to-mesenchymal transition (EMT) is an important process leading to high mortality and poor prognosis. The EMT is a fundamental process for morphogenesis characterized by the transformation of cancer cells into invasive forms that can be transferred to other organs during human lung cancer progression. Gefitinib, an epidermal growth factor receptor (EGFR) inhibitor, has shown anti-proliferative effects in EGFR-mutated NSCLC cells and an inhibitory effect on migration and invasion of NSCLC cells to other organs. In this study, we evaluated the combinatorial treatment effect of cilengitide, a cyclic RGD pentapeptide, on TGF-β1-induced EMT phenotype and invasion. Gefitinib suppressed the expression of TGF-β1-induced mesenchymal markers by inhibiting Smad and non-Smad signaling pathways. Cilengitide enhanced the inhibitory effect of gefitinib on TGF-β1-induced expression of mesenchymal markers, phosphorylation of Smad2/3, and invasion of NSCLC A549 cells. We suggested that the use of cilengitide can improve the efficacy of anti-cancer drugs in combination drug-based chemotherapy. These results provide an improved therapeutic strategy for treating and preventing EMT-related disorders, such as NSCLC, lung fibrosis, cancer metastasis, and relapse.

Akt kinase LANCL2 functions as a key driver in EGFR-mutant lung adenocarcinoma tumorigenesis

Epidermal growth factor receptor (EGFR) is a key oncogene in lung adenocarcinoma (LUAD). Resistance to EGFR tyrosine kinase inhibitors is a major obstacle for EGFR-mutant LUAD patients. Our gene chip array, quantitative polymerase chain reaction validation, and shRNA-based high-content screening identified the Akt kinase lanthionine synthetase C-like protein 2 (LANCL2) as a pro-proliferative gene in the EGFR-mutant LUAD cell line PC9. Therefore, we investigated whether LANCL2 plays a role in promoting cell proliferation and drug resistance in EGFR-mutant LUAD. In silico clinical correlation analysis using the Cancer Genome Atlas Lung Adenocarcinoma dataset revealed a positive correlation between LANCL2 and EGFR expression and an inverse relationship between LANCL2 gain-of-function and survival in LUAD patients. The EGFR-mutant LUAD cell lines PC9 and HCC827 displayed higher LANCL2 expression than the non-EGFR-mutant cell line A549. In addition, LANCL2 was downregulated following gefitinib+pemetrexed combination therapy in PC9 cells. LANCL2 knockdown reduced proliferation and enhanced apoptosis in PC9, HCC827, and A549 cells in vitro and suppressed murine PC9 xenograft tumor growth in vivo. Notably, LANCL2 overexpression rescued these effects and promoted gefitinib + pemetrexed resistance in PC9 and HCC827 cells. Pathway analysis and co-immunoprecipitation followed by mass spectrometry of differentially-expressed genes in LANCL2 knockdown cells revealed enrichment of several cancer signaling pathways. In addition, Filamin A and glutathione S-transferase Mu 3 were identified as two novel protein interactors of LANCL2. In conclusion, LANCL2 promotes tumorigenic proliferation, suppresses apoptosis, and promotes gefitinib+pemetrexed resistance in EGFR-mutant LUAD cells. Based on the positive association between LANCL2, EGFR, and downstream Akt signaling, LANCL2 may be a promising new therapeutic target for EGFR-mutant LUAD.

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.

Efficacy of the CDK4/6 Dual Inhibitor Abemaciclib in EGFR-Mutated NSCLC Cell Lines with Different Resistance Mechanisms to Osimertinib

Simple Summary

Osimertinib, a third-generation irreversible epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI), has shown marked clinical benefit for non-small cell lung cancer (NSCLC) patients with EGFR activating mutations. However, resistance to osimertinib inevitably develops and heterogeneous mechanisms of acquired resistance have been documented. Therefore, new strategies to bypass resistance are urgently needed. In this study, we investigated the potential activity of abemaciclib as second-line therapeutic approach after osimertinib progression and the effect of combining abemaciclib with osimertinib on the appearance of resistance in osimertinib-sensitive models.

Abstract

Abemaciclib is an inhibitor of cyclin-dependent kinases (CDK) 4 and 6 that inhibits the transition from the G1 to the S phase of the cell cycle by blocking downstream CDK4/6-mediated phosphorylation of Rb. The effects of abemaciclib alone or combined with the third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) osimertinib were examined in a panel of PC9 and HCC827 osimertinib-resistant non-small cell lung cancer (NSCLC) cell lines carrying EGFR-dependent or -independent mechanisms of intrinsic or acquired resistance. Differently from sensitive cells, all the resistant cell lines analyzed maintained p-Rb, which may be considered as a biomarker of osimertinib resistance and a potential target for therapeutic intervention. In these models, abemaciclib inhibited cell growth, spheroid formation, colony formation, and induced senescence, and its efficacy was not enhanced in the presence of osimertinib. Interestingly, in osimertinib sensitive PC9, PC9T790M, and H1975 cells the combination of abemaciclib with osimertinib significantly inhibited the onset of resistance in long-term experiments. Our findings provide a preclinical support for using abemaciclib to treat resistance in EGFR mutated NSCLC patients progressed to osimertinib either as single treatment or combined with osimertinib, and suggest the combination of osimertinib with abemaciclib as a potential approach to prevent or delay osimertinib resistance in first-line treatment.

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.

TMEM16A-inhibitor loaded pH-responsive nanoparticles: A novel dual-targeting antitumor therapy for lung adenocarcinoma

To overcome the adverse effects of conventional chemotherapy for cancers, various nanoparticles based drug delivery systems have been developed. However, nanoparticles delivering drugs directly to kill tumor cells still faced with challenges, because tumors possessed adopt complex mechanism to resist damages, which compromised the therapeutic efficacy. TMEM16A/CaCCs (Calcium activates chloride channels) has been identified to be overexpressed in lung adenocarcinoma which can serve as a novel tumor specific drug target in our previous work. Here, we developed a novel dual-targeted antitumor strategy via designing a novel nano-assembled, pH-sensitive drug-delivery system loading with specific inhibitors of TMEM16A against lung adenocarcinoma. For validation, we assayed the novel dual-targeting therapy on xenograft mouse model which exhibited significant antitumor activity and not affect mouse body weight. The dual targeting therapy accomplished in this study will shed light on the development of advanced antitumor strategy.

Determining the appropriate treatment for different EGFR mutations in non-small cell lung cancer patients

Introduction: Epidermal growth factor receptor (EGFR) mutations occur in a significant fraction of non-small cell lung cancer (NSCLC) patients. Most common activating mutations are in-frame deletion in exon 19 and point mutation in exon 21. EGFR tyrosine kinase inhibitors (TKIs) represent standard of care of EGFR mutated patients bearing common mutations. Therapy for individuals carrying uncommon mutations, such as G719X, L861Q, S768I, is less defined and few options exist for individuals harboring EGFR exon 20 mutations. In all mutated patients, drug resistance remains the most critical clinical problem and new agents and strategies are under investigation.Areas covered: We have reviewed the current status of NSCLC EGFR mutated treatment by analyzing data from preclinical studies, clinical prospective and retrospective trials in order to analyze current and future options for patients harboring different EGFR mutations.Expert opinion: At the present time, available data demonstrated that osimertinib is the best EGFR-TKI for front-line therapy. Other agents, such as dacomitinib, and new drug combinations, such as regimens including anti-angiogenic agents or chemotherapy, demonstrated to significantly prolong progression-free survival or overall survival, representing potential alternative to osimertinib. Many questions remain opened, including best drug sequencing and needing of new therapeutic approaches extending patient survival and cure rate.

Pemetrexed Enhances Membrane PD-L1 Expression and Potentiates T Cell-Mediated Cytotoxicity by Anti-PD-L1 Antibody Therapy in Non-Small-Cell Lung Cancer

Immunotherapy has significantly changed the treatment landscape for advanced non-small-cell lung cancer (NSCLC) with the introduction of drugs targeting programmed cell death protein-1 (PD-1) and programmed cell death ligand-1 (PD-L1). In particular, the addition of the anti-PD-1 antibody pembrolizumab to platinum-pemetrexed chemotherapy resulted in a significantly improved overall survival in patients with non-squamous NSCLC, regardless of PD-L1 expression. In this preclinical study, we investigated whether chemotherapy can modulate PD-L1 expression in non-squamous NSCLC cell lines, thus potentially affecting immunotherapy efficacy. Among different chemotherapeutic agents tested, only pemetrexed increased PD-L1 levels by activating both mTOR/P70S6K and STAT3 pathways. Moreover, it also induced the secretion of cytokines, such as IFN-γ and IL-2, by activated peripheral blood mononuclear cells PBMCs that further stimulated the expression of PD-L1 on tumor cells, as demonstrated in a co-culture system. The anti-PD-1/PD-L1 therapy enhanced T cell-mediated cytotoxicity of NSCLC cells treated with pemetrexed and expressing high levels of PD-L1 in comparison with untreated cells. These data may explain the positive results obtained with pemetrexed-based chemotherapy combined with pembrolizumab in PD-L1-negative NSCLC and can support pemetrexed as one of the preferable chemotherapy partners for immunochemotherapy combination regimens.

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.

Efficacy and safety of first line treatments for patients with advanced epidermal growth factor receptor mutated, non-small cell lung cancer: systematic review and network meta-analysis

OBJECTIVE

To compare the efficacy and safety of first line treatments for patients with advanced epidermal growth factor receptor (EGFR) mutated non-small cell lung cancer (NSCLC).

DESIGN

Systematic review and network meta-analysis.

DATA SOURCES

PubMed, Embase, Cochrane Central Register of Controlled Trials, ClinicalTrials.gov, and several international conference databases, from inception to 20 May 2019.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Published and unpublished randomised controlled trials comparing two or more treatments in the first line setting for patients with advanced EGFR mutated NSCLC were included in a bayesian network meta-analysis. Eligible studies reported at least one of the following clinical outcome measures: progression free survival, overall survival, objective response rate, and adverse events of grade 3 or higher.

RESULTS

18 eligible trials involved 4628 patients and 12 treatments: EGFR tyrosine kinase inhibitors (TKIs; osimertinib, dacomitinib, afatinib, erlotinib, gefitinib, and icotinib), pemetrexed based chemotherapy, pemetrexed free chemotherapy, and combination treatments (afatinib plus cetuximab, erlotinib plus bevacizumab, gefitinib plus pemetrexed based chemotherapy, and gefitinib plus pemetrexed). Consistent with gefitinib plus pemetrexed based chemotherapy (hazard ratio 0.95, 95% credible interval 0.72 to 1.24), osimertinib showed the most favourable progression free survival, with significant differences versus dacomitinib (0.74, 0.55 to 1.00), afatinib (0.52, 0.40 to 0.68), erlotinib (0.48, 0.40 to 0.57), gefitinib (0.44, 0.37 to 0.52), icotinib (0.39, 0.24 to 0.62), pemetrexed based chemotherapy (0.24, 0.17 to 0.33), pemetrexed free chemotherapy (0.16, 0.13 to 0.20), afatinib plus cetuximab (0.44, 0.28 to 0.71), and gefitinib plus pemetrexed (0.65, 0.46 to 0.92). Osimertinib and gefitinib plus pemetrexed based chemotherapy were also consistent (0.94, 0.66 to 1.35) in providing the best overall survival benefit. Combination treatments caused more toxicity in general, especially erlotinib plus bevacizumab, which caused the most adverse events of grade 3 or higher. Different toxicity spectrums were revealed for individual EGFR-TKIs. Subgroup analyses by the two most common EGFR mutation types indicated that osimertinib was associated with the best progression free survival in patients with the exon 19 deletion, and gefitinib plus pemetrexed based chemotherapy was associated with the best progression free survival in patients with the Leu858Arg mutation.

CONCLUSIONS

These results indicate that osimertinib and gefitinib plus pemetrexed based chemotherapy were associated with the best progression free survival and overall survival benefits for patients with advanced EGFR mutated NSCLC, compared with other first line treatments. The treatments resulting in the best progression free survival for patients with the exon 19 deletion and Leu858Arg mutations were osimertinib and gefitinib plus pemetrexed based chemotherapy, respectively.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42018111954.

Acquired Resistance to EGFR TKIs Mediated by TGFβ1/Integrin β3 Signaling in EGFR-Mutant Lung Cancer

Investigation of novel molecular mechanisms is essential to develop strategies to overcome acquired resistance to EGFR tyrosine kinase inhibitors (TKI). Integrin has been demonstrated as a regulator of cancer progression. The aim of this study was to identify which specific integrins are involved and regulated in acquired resistance to EGFR TKIs in EGFR-mutant lung cancer. The expression levels of integrin subunits were examined in EGFR-mutant lung cancer cells and xenograft tumors with acquired resistance to EGFR TKIs. Manipulation of integrin β3 was performed to explore whether integrin β3 overexpression was associated with TKI resistance, anoikis resistance, EMT, and cancer stemness in resistant lung cancer. To explore the mechanism, TGFβ1 level was examined, and TGFβ1 inhibitor was then used. Integrin β3 was dramatically and consistently overexpressed in acquired gefitinib- or osimertinib-resistant lung cancer in vitro and in vivo Integrin β3 was also involved in the progression of lung adenocarcinoma. Antagonizing integrin β3 increased the TKI sensitivity and delayed the occurrence of TKI resistance in vitro and in vivo, as well as suppressed proliferation, anoikis resistance, and EMT phenotype in lung cancer cells. Overexpression of integrin β3 was also associated with the enhanced cancer stemness that was acquired in the development of resistance and suppressed by antagonizing integrin β3. Mechanistically, integrin β3 was induced by increased TGFβ1 levels in acquired TKI-resistant lung cancer. Our study identified the TGFβ1/integrin β3 axis as a promising target for combination therapy to delay or overcome acquired resistance to EGFR TKIs in EGFR-mutant lung cancer.

Epidermal Growth Factor Receptor (EGFR)-Tyrosine Kinase Inhibitors (TKIs) Combined with Chemotherapy Delay Brain Metastasis in Patients with EGFR-Mutant Lung Adenocarcinoma

BACKGROUND

Whether epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) combined with chemotherapy can delay the occurrence of brain metastasis (BM) is unclear.

OBJECTIVE

This retrospective study aimed to evaluate whether EGFR-TKIs combined with chemotherapy can delay BM and decrease the incidence of BM as initial progression.

PATIENTS AND METHODS

The data of 100 patients with EGFR-mutant advanced lung adenocarcinoma were retrospectively reviewed. The patients had no BM at initial diagnosis, and BM occurred during the treatment. Patients received EGFR-TKI only or EGFR-TKI combined with chemotherapy. Intracranial progression-free survival (iPFS), systemic progression-free survival (PFS), and overall survival (OS) were evaluated.

RESULTS

The overall median OS was 39 months (95% confidence interval (CI), 35.6-42.4 months). The median OS of EGFR-TKI combined with chemotherapy and EGFR-TKI only are 41 months (95% CI 35.5-46.5 months) and 39 months (95% CI 36.8-41.2 months), respectively. Patients in the combination treatment group had longer PFS (16 vs. 10 months; P = 0.030) and iPFS (21 vs. 14 months; P = 0.026). Further, as initial progression, fewer patients developed BM in the combined treatment group compared with the EGFR-TKI-only group (30.6% vs. 52.9%, P = 0.002) with a hazard ratio of 0.64 (95% CI 0.43-0.96). After controlling for significant covariables in a multivariable model, the different treatment strategies were independently associated with improved iPFS.

CONCLUSIONS

In this retrospective analysis, EGFR-TKIs combined with chemotherapy could improve PFS. Further, the combined treatment could delay BM occurrence and decrease the incidence of BM as initial progression.

Third generation EGFR inhibitor osimertinib combined with pemetrexed or cisplatin exerts long-lasting anti-tumor effect in EGFR-mutated pre-clinical models of NSCLC

BACKGROUND

The third generation Epidermal Growth Factor Receptor (EGFR) Tyrosine Kinase Inhibitor (TKI) osimertinib has been initially approved for T790M positive Non-Small Cell Lung Cancer (NSCLC) and more recently for first-line treatment of EGFR-mutant T790M negative NSCLC patients. Similarly to previous generation TKIs, despite the high response rate, disease progression eventually occurs and current clinical research is focused on novel strategies to delay the emergence of osimertinib resistance. In this study we investigated the combination of osimertinib with pemetrexed or cisplatin in EGFR-mutated NSCLC cell lines and xenografts.

METHODS

Tumor growth was evaluated in a PC9T790M xenograft model and tissue composition was morphometrically determined. PC9, PC9T790M and HCC827 cell lines were employed to test the efficacy of osimertinib and chemotherapy combination in vitro. Cell viability and cell death were evaluated by MTT assay and fluorescence microscopy. Protein expression and gene status were analysed by Western blotting, fluorescence in situ hybridization analysis, next-generation sequencing and digital droplet PCR.

RESULTS

In xenograft models, osimertinib significantly inhibited tumor growth, however, as expected, in 50% of mice drug-resistance developed. A combination of osimertinib with pemetrexed or cisplatin prevented or at least delayed the onset of resistance. Interestingly, such combinations increased the fraction of fibrotic tissue and exerted a long-lasting activity after stopping therapy. In vitro studies demonstrated the stronger efficacy of the combination over the single treatments in inhibiting cell proliferation and inducing cell death in PC9T790M cells as well as in T790M negative PC9 and HCC827 cell lines, suggesting the potential role of this strategy also as first-line treatment. Finally, we demonstrated that osimertinib resistant clones, either derived from resistant tumors or generated in vitro, were less sensitive to pemetrexed prompting to use a chemotherapy regimen non-containing pemetrexed in patients after progression to osimertinib treatment.

CONCLUSIONS

Our results identify a combination between osimertinib and pemetrexed or cisplatin potentially useful in the treatment of EGFR-mutated NSCLC patients, which might delay the appearance of osimertinib resistance with long-lasting effects.

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 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.

Epigenetic silencing of miR-483-3p promotes acquired gefitinib resistance and EMT in EGFR-mutant NSCLC by targeting integrin β3

All lung cancers patients with epidermal growth factor receptor (EGFR) mutation inevitably develop acquired resistance to EGFR tyrosine kinase inhibitors (TKI). In up to 30% of cases, the mechanism underlying acquired resistance remains unknown. MicroRNAs (miRNAs) is a group of small non-coding RNAs commonly dysregulated in human cancers and have been implicated in therapy resistance. The aim of this study was to understand the roles of novel miRNAs in acquired EGFR TKI resistance in EGFR-mutant non-small cell lung cancer (NSCLC). Here, we reported the evidence of miR-483-3p silencing and epithelial-to-mesenchymal transition (EMT) phenotype in both in vitro and in vivo EGFR-mutant NSCLC models with acquired resistance to gefitinib. In those tumor models, forced expression of miR-483-3p efficiently increased sensitivity of gefitinib-resistant lung cancer cells to gefitinib by inhibiting proliferation and promoting apoptosis. Moreover, miR-483-3p reversed EMT and inhibited migration, invasion, and metastasis of gefitinib-resistant lung cancer cells. Mechanistically, miR-483-3p directly targeted integrin β3, and thus repressed downstream FAK/Erk signaling pathway. Furthermore, the silencing of miR-483-3p in gefitinib-resistant lung cancer cells was due to hypermethylation of its own promoter. Taken together, our data identify miR-483-3p as a promising target for combination therapy to overcome acquired EGFR TKI resistance in EGFR-mutant NSCLC.

The anti-tumor efficacy of CDK4/6 inhibition is enhanced by the combination with PI3K/AKT/mTOR inhibitors through impairment of glucose metabolism in TNBC cells

Background

Cell cycle regulators have gain attention as potential targets for anticancer therapy. Palbociclib is a selective inhibitor of the cyclin-dependent kinases 4 and 6 (CDK4/6), which coordinate the G1-S transition. Palbociclib is currently approved for the treatment of hormone receptor positive, HER2-negative advanced breast cancer (BC) in association with letrozole or fulvestrant. In contrast, its efficacy in triple negative BC (TNBC), either alone or in combined therapies, has not been fully investigated to date.

Methods

Here we evaluated the potential of combining palbociclib with PI3K/mTOR inhibitors in Rb-proficient TNBC cells comparing different schedules of treatment: simultaneous, sequential, or sequential combined treatment (pre-incubation with palbociclib followed by exposure to both palbociclib and PI3K/mTOR inhibitors). We assessed the effects on cell proliferation, cell death, and cell cycle distribution, and looked at the impact of such treatments on glucose metabolism.

Results

Palbociclib exerted cytostatic effects in Rb-positive TNBC cells, inducing a reversible blockade in G0/G1 cell cycle phase associated with down-regulation of CDK6, Rb, and c-myc expression and/or activity. Palbociclib treatment induced AKT signaling, providing a rationale for its combination with PI3K/mTOR inhibitors. The simultaneous or sequential treatment resulted in an additive inhibition of cell proliferation. On the other hand, the sequential combined treatment in which palbociclib was maintained also during exposure to PI3K/mTOR inhibitors gave rise to synergistic anti-proliferative and pro-apoptotic effects, by inhibiting both CDK4/6/Rb/myc and PI3K/mTOR signaling. Interestingly, the inhibition of the Rb/E2F/myc axis mediated by palbociclib resulted in a significant down-regulation of glucose metabolism; most importantly, these inhibitory effects were enhanced by the combination of palbociclib with BYL719 (specific inhibitor of the p110α PI3K-subunit), which promoted a stronger inhibition of GLUT-1 glucose transporter expression, glucose uptake and consumption in comparison with individual treatments, under both normoxic and hypoxic conditions.

Conclusions

Combination of palbociclib with PI3K/mTOR inhibitors may represent a promising therapeutic option for the treatment of Rb-proficient TNBC, with the sequential combined schedule showing a superior efficacy over the other schedules. In addition our results demonstrate that the impairment of glucose metabolism may contribute to the anti-tumor activity of such drug combinations.

MTOR inhibition reversed drug resistance after combination radiation with erlotinib in lung adenocarcinoma

Objective

To investigate the effects of mTOR inhibition on drug resistance in lung adenocarcinoma after combined radiation and erlotinib therapy.

Results

Combined radiation and erlotinib therapy produced clear radiosensitization effects both in vitro and in vivo; however, tumor cells remained drug resistant. Additionally, combined radiation and erlotinib therapy significantly increased p-AKT and p-P70 levels. After mTOR inhibition, the number of surviving cells significantly decreased compared with that before inhibition, and the in vivo growth curve was significantly reduced.

Methods

The effects of combined radiation and erlotinib therapy on tumor inhibition and drug resistance were evaluated by in vitro survival curves in PC9 lung adenocarcinoma cell line and in vivo growth curves in nude mouse xenograft tumor model respectively. The association between tumor drug resistance and the phosphatidylinositol 3-kinase/protein kinase B/mechanistic target of rapamycin (PI3K-AKT-mTOR) pathway was measured by western blot, assessing the changes in protein kinase B (AKT), phosphor-AKT (p-AKT), P70, and p-P70 protein levels. MTOR was inhibited using everolimus, and changes in AKT, p-AKT, P70, and p-P70 levels were observed. Furthermore, changes in in vitro survival curves, and in vivo growth curves before and after mTOR inhibition were evaluated to confirm its effects on drug resistance in lung adenocarcinoma after combined radiation and TKI therapy.

Conclusion

mTOR was associated with drug resistance in lung adenocarcinoma after radiation combined with TKI, and MTOR inhibition reversed drug resistance in lung adenocarcinoma after combined radiation and TKI therapy.

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.

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.

Trastuzumab emtansine delays and overcomes resistance to the third-generation EGFR-TKI osimertinib in NSCLC EGFR mutated cell lines

BACKGROUND

Osimertinib is a third-generation EGFR-TKI with a high selective potency against T790M-mutant NSCLC patients. Considering that osimertinib can lead to enhanced HER-2 expression on cell surface and HER-2 overexpression is a mechanism of resistance to osimertinib, this study was addressed to investigate the potential of combining osimertinib with trastuzumab emtansine (T-DM1) in order to improve the efficacy of osimertinib and delay or overcome resistance in NSCLC cell lines with EGFR activating mutation and with T790M mutation or HER-2 amplification.

METHODS

The effects of osimertinib combined with T-DM1 on cell proliferation, cell cycle, cell death, antibody-dependent cell-mediated cytotoxicity (ADCC), and acquisition of osimertinib resistance was investigated in PC9, PC9-T790M and H1975 cell lines. The potential of overcoming osimertinib resistance with T-DM1 was tested in a PC9/HER2c1 xenograft model.

RESULTS

T-DM1 exerted an additive effect when combined with osimertinib in terms of inhibition of cell proliferation, cell death and ADCC induction in PC9, PC9-T790M and H1975 cell lines. Combining osimertinib and T-DM1 using different schedules in long-term growth experiments revealed that the appearance of osimertinib-resistance was prevented in PC9-T790M and delayed in H1975 cells when the two drugs were given together. By contrast, when osimertinib was followed by T-DM1 an antagonistic effect was observed on cell proliferation, cell death and resistance acquisition. In xenograft models, we demonstrated that HER-2 amplification was associated with osimertinib-resistance and that T-DM1 co-administration is a potential strategy to overcome this resistance.

CONCLUSIONS

Our data suggest that concomitant treatment with osimertinib and T-DM1 may be a promising therapeutic strategy for EGFR-mutant NSCLC.

Continuation of gefitinib plus chemotherapy prolongs progression-free survival in advanced non-small cell lung cancer patients who get acquired resistance to gefitinib without T790M mutations

Background

Aimed to identify the benefit population from continuation of epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs), this study investigated the efficacy of continuation of EGFR-TKIs plus chemotherapy beyond the response evaluation criteria in solid tumors-progressive disease (RECIST-PD) according to different progression modes and T790M mutational status.

Methods

From November 2009 to July 2015, 630 patients with advanced non-small cell lung cancer (NSCLC) receiving gefitinib as initial EGFR-TKI treatment were screened in Shanghai Pulmonary Hospital. A total of 170 patients with documented gradual or dramatic progression after gefitinib treatment who received chemotherapy alone or in combination with gefitinib were included. Post-RECIST-PD progression-free survival (PPFS) between continuation of gefitinib plus chemotherapy and chemotherapy alone was assessed.

Results

The incidence of T790M mutation was 42.9% (63/147) in patients who got acquired resistance in this study. Median PPFS was 4.0 months [95% confidence interval (CI), 3.1-4.9 months] in the chemotherapy group and 5.0 months (95% CI, 3.6-6.4 months) in the combination group with a borderline statistical significance (P=0.071). Continuation of gefitinib plus chemotherapy resulted in a significant improvement in PPFS compared with chemotherapy alone in patients with EGFR^T790M-negative tumors [median PPFS: 6.6 vs. 3.5 months, hazard ratio (HR) 0.50, 95% CI, 0.29-0.88; P=0.011], especially in pemetrexed-based chemotherapy (HR 0.45, 95% CI, 0.24-0.86; P=0.011). PPFS was similar in patients with EGFR^T790M-positive tumors (median PPFS: 5.0 vs. 5.5 months, HR 0.80, 95% CI, 0.40-1.61; P=0.520) or EGFR^T790M-unknown tumors (median PPFS: 2.0 vs. 3.0 months, HR 1.40, 95% CI, 0.69-2.81; P=0.323).

Conclusions

Our study showed that continuous gefitinib plus chemotherapy, especially pemetrexed-based therapy, significantly improved PPFS in patients with EGFR^T790M-negative tumors as compared with chemotherapy alone, suggesting that this subtype of patients may derive clinical benefit from continuation of gefitinib treatment beyond progression.

Enhancement of the anti-tumor activity of FGFR1 inhibition in squamous cell lung cancer by targeting downstream signaling involved in glucose metabolism

Fibroblast Growth Factor Receptor (FGFR) signaling is a complex pathway which controls several processes, including cell proliferation, survival, migration, and metabolism. FGFR1 signaling is frequently deregulated via amplification/over-expression in NSCLC of squamous histotype (SQCLC), however its inhibition has not been successfully translated in clinical setting. We determined whether targeting downstream signaling implicated in FGFR1 effects on glucose metabolism potentiates the anti-tumor activity of FGFR1 inhibition in SQCLC. In FGFR1 amplified/over-expressing SQCLC cell lines, FGF2-mediated stimulation of FGFR1 under serum-deprivation activated both MAPK and AKT/mTOR pathways and increased glucose uptake, glycolysis, and lactate production, through AKT/mTOR-dependent HIF-1α accumulation and up-regulation of GLUT-1 glucose transporter. These effects were hindered by PD173074 and NVP-BGJ398, selective FGFR inhibitors, as well as by dovitinib, a multi-kinase inhibitor. Glucose metabolism was hampered by the FGFR inhibitors also under hypoxic conditions, with consequent inhibition of cell proliferation and viability. In presence of serum, glucose metabolism was impaired only in cell models in which FGFR1 inhibition was associated with AKT/mTOR down-regulation. When the activation of the AKT/mTOR pathway persisted despite FGFR1 down-regulation, the efficacy of NVP-BGJ398 could be significantly improved by the combination with NVP-BEZ235 or other inhibitors of this signaling cascade, both in vitro and in xenotransplanted nude mice. Collectively our results indicate that inhibition of FGFR1 signaling impacts on cancer cell growth also by affecting glucose energy metabolism. In addition, this study strongly suggests that the therapeutic efficacy of FGFR1 targeting molecules in SQCLC may be implemented by combined treatments tackling on glucose metabolism.

Combined Inhibition of CDK4/6 and PI3K/AKT/mTOR Pathways Induces a Synergistic Anti-Tumor Effect in Malignant Pleural Mesothelioma Cells

Malignant pleural mesothelioma (MPM) is a progressive malignancy associated to the exposure of asbestos fibers. The most frequently inactivated tumor suppressor gene in MPM is CDKN2A/ARF, encoding for the cell cycle inhibitors p16^INK4a and p14^ARF, deleted in about 70% of MPM cases. Considering the high frequency of alterations of this gene, we tested in MPM cells the efficacy of palbociclib (PD-0332991), a highly selective inhibitor of cyclin-dependent kinase (CDK) 4/6. The analyses were performed on a panel of MPM cell lines and on two primary culture cells from pleural effusion of patients with MPM. All the MPM cell lines, as well as the primary cultures, were sensitive to palbociclib with a significant blockade in G0/G1 phase of the cell cycle and with the acquisition of a senescent phenotype. Palbociclib reduced the phosphorylation levels of CDK6 and Rb, the expression of myc with a concomitant increased phosphorylation of AKT. Based on these results, we tested the efficacy of the combination of palbociclib with the PI3K inhibitors NVP-BEZ235 or NVP-BYL719. After palbociclib treatment, the sequential association with PI3K inhibitors synergistically hampered cell proliferation and strongly increased the percentage of senescent cells. In addition, AKT activation was repressed while p53 and p21 were up-regulated. Interestingly, two cycles of sequential drug administration produced irreversible growth arrest and senescent phenotype that were maintained even after drug withdrawal. These findings suggest that the sequential association of palbociclib with PI3K inhibitors may represent a valuable therapeutic option for the treatment of MPM.