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

Mechanisms of resistance to tyrosine kinase inhibitor-targeted therapy and overcoming strategies

Tyrosine kinase inhibitor (TKI)-targeted therapy has revolutionized cancer treatment by selectively blocking specific signaling pathways crucial for tumor growth, offering improved outcomes with fewer side effects compared with conventional chemotherapy. However, despite their initial effectiveness, resistance to TKIs remains a significant challenge in clinical practice. Understanding the mechanisms underlying TKI resistance is paramount for improving patient outcomes and developing more effective treatment strategies. In this review, we explored various mechanisms contributing to TKI resistance, including on-target mechanisms and off-target mechanisms, as well as changes in the tumor histology and tumor microenvironment (intrinsic mechanisms). Additionally, we summarized current therapeutic approaches aiming at circumventing TKI resistance, including the development of next-generation TKIs and combination therapies. We also discussed emerging strategies such as the use of dual-targeted antibodies and PROteolysis Targeting Chimeras. Furthermore, we explored future directions in TKI-targeted therapy, including the methods for detecting and monitoring drug resistance during treatment, identification of novel targets, exploration of dual-acting kinase inhibitors, application of nanotechnologies in targeted therapy, and so on. Overall, this review provides a comprehensive overview of the challenges and opportunities in TKI-targeted therapy, aiming to advance our understanding of resistance mechanisms and guide the development of more effective therapeutic approaches in cancer treatment.

Management of Treatment Resistance in Patients With Advanced Epidermal Growth Factor Receptor-Mutated Lung Cancer: Personalization, Parsimony, and Partnership

The Oncology Grand Rounds series is designed to place original reports published in the Journal into clinical context. A case presentation is followed by a description of diagnostic and management challenges, a review of the relevant literature, and a summary of the authors' suggested management approaches. The goal of this series is to help readers better understand how to apply the results of key studies, including those published in Journal of Clinical Oncology, to patients seen in their own clinical practice.Patients with epidermal growth factor receptor (EGFR)-mutated advanced non-small-cell lung cancer represent a distinct subgroup of individuals who can experience initially tolerable and durable effects with first-line EGFR-directed tyrosine kinase inhibitors. Unfortunately, acquired treatment resistance and cancer progression within the CNS are inevitable during the disease course and present a challenging transition in the care continuum. Next-line therapies generally require combinations of drugs and afford nuanced differences in clinical outcomes relative to the treatment experience, toxicity profile, and quality of life. Therapeutic stratification and modulation thus require further personalization and partnership with patients to identify key clinical, molecular, and human-specific factors to best guide optimal care.

A retrospective study on the efficacy and safety of Endostar with chemotherapy in EGFR-TKI-resistant NSCLC

BACKGROUND

Endostar is a strong angiogenesis inhibitor that is effective in treating non-small cell lung cancer (NSCLC), but the effect of Endostar in the treatment of patients with EGFR-TKI-resistant NSCLC remains unclear. We evaluated the clinical efficacy and safety of Endostar in EGFR-mutant NSCLC patients resistant to EGFR inhibition treatment.

METHODS

From January 1, 2016 to June 30, 2018, 68 patients were selected from the 4 institutions for the study. Patients with NSCLC received Endostar plus chemotherapy every 21-day cycle. Chemotherapy types included platinum-containing dual drugs and platinum-free single drugs. Endostar was administered by intermittent intravenous infusion or continuous microinfusion pump infusion. The overall response rate (ORR), disease control rate (DCR) and adverse events were analyzed. Survival of patients was also evaluated.

RESULTS

For all patients, the median progression-free survival (PFS) was 2.8 months, and the median overall survival (OS) was 14.2 months. PFS and OS in the Endostar pump continuous group were better than those in the Endostar intravenous infusion group. The disease control rate (DCR) was 79.4%. A total of 28 (41.2%) patients experienced varying grades of adverse events during treatment. No treatment-associated deaths were observed. The grade 3 treatment-emergent adverse events (TEAEs) were myelosuppression, weakness, and nausea/vomiting.

CONCLUSIONS

Endostar was effective and well tolerated in advanced NSCLC patients. Endostar treatment showed promising survival results in EGFR-mutant NSCLC patients.

Advanced non-small-cell lung cancer treated with first-line pembrolizumab plus chemotherapy: tumor response dynamics as a marker for survival

OBJECTIVES

The study investigated tumor burden dynamics on computed tomography (CT) scans in patients with advanced non-small-cell lung cancer (NSCLC) during first-line pembrolizumab plus chemotherapy, to provide imaging markers for overall survival (OS).

METHODS

The study included 133 patients treated with first-line pembrolizumab plus platinum-doublet chemotherapy. Serial CT scans during therapy were assessed for tumor burden dynamics during therapy, which were studied for the association with OS.

RESULTS

There were 67 responders, with overall response rate of 50%. The tumor burden change at the best overall response ranged from - 100.0% to + 132.1% (median of - 30%). Higher response rates were associated with younger age (p < 0.001) and higher programmed cell death-1 (PD-L1) expression levels (p = 0.01). Eighty-three patients (62%) showed tumor burden below the baseline burden throughout therapy. Using an 8-week landmark analysis, OS was longer in patients with tumor burden below the baseline burden in the first 8 weeks than in those who experienced ≥ 0% increase (median OS: 26.8 vs. 7.6 months, hazard ratio (HR): 0.36, p < 0.001). Tumor burden remained below their baseline throughout therapy was associated with significantly reduced hazards of death (HR: 0.72, p = 0.03) in the extended Cox models, after adjusting for other clinical variables. Pseudoprogression was noted in only one patient (0.8%).

CONCLUSIONS

Tumor burden staying below the baseline burden throughout the therapy was predictive of prolonged overall survival in patients with advanced NSCLC treated with first-line pembrolizumab plus chemotherapy, and may be used as a practical marker for therapeutic decisions in this widely used combination regimen.

CLINICAL RELEVANCE STATEMENT

The analysis of tumor burden dynamics on serial CT scans in reference to the baseline burden can provide an additional objective guide for treatment decision making in patients treated with first-line pembrolizumab plus chemotherapy for their advanced NSCLC.

KEY POINTS

• Tumor burden remaining below baseline burden during therapy predicted longer survival during first-line pembrolizumab plus chemotherapy. • Pseudoprogression was noted in 0.8%, demonstrating the rarity of the phenomenon. • Tumor burden dynamics may serve as an objective marker for treatment benefit to guide treatment decisions during first-line pembrolizumab plus chemotherapy.

Novel considerations on EGFR-based therapy as a contributor to cancer cell death in NSCLC

Epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) represented by gefitinib and erlotinib are widely used in treating non-small cell lung cancer (NSCLC). However, acquired resistance to EGFR-TKI treatment remains a clinical challenge. In recent years, emerging research investigated in EGFR-TKI-based combination therapy regimens, and remarkable achievements have been reported. This article focuses on EGFR-TKI-based regimens, reviews the standard and novel application of EGFR targets, and summarizes the mechanisms of EGFR-TKI combinations including chemotherapy, anti-vascular endothelial growth factor monoclonal antibodies, and immunotherapy in the treatment of NSCLC. Additionally, we summarize clinical trials of EGFR-TKI-based combination therapy expanding indications to EGFR mutation-negative lung malignancies. Moreover, novel strategies are under research to explore new drugs with good biocompatibility. Nanoparticles encapsulating non-coding RNA and chemotherapy of new dosage forms drawn great attention and showed promising prospects in effective delivery and stable release. Overall, as the development of resistance to EGFR-TKIs treatment is inevitable in most of the cases, further research is needed to clarify the underlying mechanism of the resistance, and to evaluate and establish EGFR-TKI combination therapies to diversify the treatment landscape for NSCLC.

Case report: an initially unresectable stage III pulmonary sarcomatoid carcinoma qith EGFR mutation achieving pathological complete response following neoadjuvant therapy with osimertinib plus chemotherapy

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (EGFR-TKIs) provide dramatic response to patients with advanced EGFR-mutant non-small cell lung cancer (NSCLC). However, the use of neoadjuvant therapy with EGFR-TKIs in EGFR-mutant NSCLC remains controversial, especially in pulmonary sarcomatoid carcinoma (PSC). One patient with initially unresectable stage III (cT4N0M0) PSC was found to carry EGFR mutation by the next generation sequencing. After neoadjuvant therapy with osimertinib plus chemotherapy, radical resection of the right upper lung lesion was achieved, and the pathological results reached pathological complete response (pCR). To the best of our knowledge, this is the first report of an EGFR-mutant patient with initially unresectable stage III PSC achieved pCR by neoadjuvant therapy with osimertinib plus chemotherapy. Therefore, neoadjuvant therapy with EGFR-TKIs may be a viable option for EGFR-mutant PSC patients.

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

OBJECTIVES

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

SYSTEMIC REVIEW REGISTRATION

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

Treating disease progression with osimertinib in EGFR-mutated non-small-cell lung cancer: novel targeted agents and combination strategies

A precision medicine approach has been successfully applied in medical oncology for the treatment of non-small-cell lung cancer (NSCLC) through the identification of targetable driver molecular aberrations; activating mutations of epidermal growth factor receptor (EGFR) are the most common. Osimertinib, a third-generation, wild-type sparing, irreversible EGFR tyrosine kinase inhibitor (TKI), originally showed a striking activity after progression to first- and second-generation EGFR-TKIs when T790M resistance mutation was identified. Thereafter, upfront use of osimertinib became the standard of care based on overall survival benefit over first-generation TKIs erlotinib and gefitinib as reported in the FLAURA trial. For patients progressing on osimertinib, identification of resistance mechanisms is crucial to develop novel targeted therapeutic approaches. Moreover, innovative drugs or combination therapies are being developed for cases in which a specific resistance mechanism is not identifiable. In this review, the post-osimertinib treatment options for EGFR-mutated NSCLC are analyzed, with an outlook to ongoing clinical trials. An algorithm to guide clinicians in managing progression on osimertinib is proposed.

Tumor Growth Rate After Nadir Is Associated With Survival in Patients With EGFR-Mutant Non-Small-Cell Lung Cancer Treated With Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitor

PURPOSE

To investigate the association between tumor volume growth rate after the nadir and survival in patients with EGFR-mutant advanced non-small-cell lung cancer (NSCLC) treated with erlotinib.

MATERIALS AND METHODS

Seventy-one patients with EGFR-mutant advanced NSCLC treated with erlotinib were studied for computed tomography tumor volume kinetics during therapy. The tumor growth rate after nadir was obtained using a previously published analytic module for longitudinal volume tracking to study its relationship with overall survival (OS).

RESULTS

The median tumor volume for the cohort was 19,842 mm3 at baseline and 4,083 mm3 at nadir. The median time to nadir was 6.2 months. The tumor growth rate after nadir for logeV (the natural logarithm of tumor volume measured in mm3) was 0.11/mo on average for the cohort (SE: 0.014), which was very similar to the previously validated reference value of 0.12/mo to define slow and fast tumor growth. The OS of 48 patients with slow tumor growth (≤ 0.12/mo) was significantly longer compared with 23 patients with fast tumor growth (> 0.12/mo; median OS: 37.8 v 25.0 months; P = .0012). In Cox models, tumor growth rate was also associated with survival (regression coefficient: 3.9903; P = .0024; faster rate leads to increased hazards), after adjusting for time to nadir (regression coefficient: -0.0863; P = .0008; longer time to nadir leads to decreased hazards) and smoking history.

CONCLUSION

In patients with EGFR-mutant advanced NSCLC treated with erlotinib, slower tumor growth rates after nadir were associated with longer OS, providing a rationale for using tumor growth rates to guide precision therapy for lung cancer.

Tumor Growth Rate After Nadir Is Associated With Survival in Patients With EGFR-Mutant Non-Small-Cell Lung Cancer Treated With Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitor

PURPOSE

To investigate the association between tumor volume growth rate after the nadir and survival in patients with EGFR-mutant advanced non-small-cell lung cancer (NSCLC) treated with erlotinib.

MATERIALS AND METHODS

Seventy-one patients with EGFR-mutant advanced NSCLC treated with erlotinib were studied for computed tomography tumor volume kinetics during therapy. The tumor growth rate after nadir was obtained using a previously published analytic module for longitudinal volume tracking to study its relationship with overall survival (OS).

RESULTS

The median tumor volume for the cohort was 19,842 mm³ at baseline and 4,083 mm³ at nadir. The median time to nadir was 6.2 months. The tumor growth rate after nadir for log_eV (the natural logarithm of tumor volume measured in mm³) was 0.11/mo on average for the cohort (SE: 0.014), which was very similar to the previously validated reference value of 0.12/mo to define slow and fast tumor growth. The OS of 48 patients with slow tumor growth (≤ 0.12/mo) was significantly longer compared with 23 patients with fast tumor growth (> 0.12/mo; median OS: 37.8 v 25.0 months; P = .0012). In Cox models, tumor growth rate was also associated with survival (regression coefficient: 3.9903; P = .0024; faster rate leads to increased hazards), after adjusting for time to nadir (regression coefficient: -0.0863; P = .0008; longer time to nadir leads to decreased hazards) and smoking history.

CONCLUSION

In patients with EGFR-mutant advanced NSCLC treated with erlotinib, slower tumor growth rates after nadir were associated with longer OS, providing a rationale for using tumor growth rates to guide precision therapy for lung cancer.

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.

Drug interaction of ningetinib and gefitinib involving CYP1A1 and efflux transporters in non-small cell lung cancer patients

AIMS

Ningetinib is a tyrosine kinase inhibitor for the treatment of non-small cell lung cancer (NSCLC). The present study aims to investigate the drug interaction of ningetinib and gefitinib and the mechanism of high plasma exposure of N-demethylated ningetinib (M1) in NSCLC patients.

METHODS

Patients with NSCLC were recruited. Metabolism and transport assays were performed using in vitro models. Deuterated M1 was used to study the effects of ningetinib and gefitinib on M1 efflux in Institute of Cancer Research (ICR) mice.

RESULTS

Upon co-administration of ningetinib with gefitinib, the plasma exposure of M1 was reduced by 80%, whereas that of ningetinib was not affected. In vitro experiments indicated that CYP1A1 was primarily responsible for M1 formation. Gefitinib was demonstrated to be a strong inhibitor of CYP1A1 with K_i value of 0.095 μM. M1 was identified as a substrate of efflux transporters P-gp and BCRP, while ningetinib and gefitinib were demonstrated to be their inhibitors, which was consistent with the results in mice. However, the inhibitory effect of gefitinib on efflux in vivo was negligible in the presence of ningetinib.

CONCLUSION

The high plasma exposure of M1 in patients was attributed to the inhibition of M1 efflux by ningetinib and its low tissue affinity. When co-administered, gefitinib inhibited the formation of M1, but due to the low metabolic yield of M1 in vivo, the pharmacokinetics of ningetinib was not influenced. Inhibition of CYP1A1 may increase the concentration of ningetinib in target tissues, and the long-term safety and efficacy of ningetinib combined with gefitinib should be evaluated.

Inhibition of DNA‑PK by gefitinib causes synergism between gefitinib and cisplatin in NSCLC

Lung cancer has the highest incidence and mortality rates among the malignant tumor types worldwide. Platinum‑based chemotherapy is the main treatment for advanced non‑small‑cell lung cancer (NSCLC), and epidermal growth factor receptor‑tyrosine kinase inhibitors (EGFR‑TKIs) have greatly improved the survival of patients with EGFR‑sensitive mutations. However, there is no standard therapy for treating patients who are EGFR‑TKI resistant. Combining EGFR‑TKIs and platinum‑based chemotherapy is the most popular strategy in the clinical practice. However, the synergistic mechanism between EGFR‑TKIs and platinum remains unknown. Therefore, the aim of the present study was to determine the synergistic mechanism of gefitinib (an EGFR‑TKI) and cisplatin (a main platinum‑based drug). MTT assay, apoptosis analysis, tumorsphere formation and an orthotropic xenograft mouse model were used to examine the combination effects of gefitinib and cisplatin on NSCLC. Co‑immunoprecipitation and immunofluorescence were used to identify the underlying mechanism. It was found that gefitinib could selectively inhibit EGFR from entering the nucleus, decrease DNA‑PK activity and enhance the cytotoxicity of cisplatin on NSCLC. Collectively, the results suggested that inhibition of DNA‑dependent protein kinase by gefitinib may be due to the synergistic mechanism between gefitinib and cisplatin. Thus, the present study provides a novel insight into potential biomarkers for the selection of combination therapy of gefitinib and cisplatin.

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.

Icotinib and pemetrexed in treatment of lung adenocarcinoma and the effects on prognostic survival rate of patients

Efficacy comparison of icotinib and pemetrexed in the treatment of lung adenocarcinoma and the effects on the prognostic survival rate of patients were investigated. A retrospective analysis was performed in 132 lung adenocarcinoma patients who were treated in the Affiliated Hospital of Weifang Medical University from July 2010 to July 2015. Among them, 69 patients were treated with icotinib (icotinib group), and 63 patients were treated with pemetrexed (pemetrexed group). In the icotinib group, 125 mg icotinib was orally administered continuously, 3 times a day, until progressive disease or intolerable adverse reactions occurred. In the pemetrexed group, 500 mg/m² pemetrexed was intravenously dripped for a total of 4 cycles, 21 days for 1 cycle, until progressive disease or intolerable adverse reactions occurred. The efficacy, toxic and side effects, and survival rate of the two groups were evaluated. There was a statistically significant difference in toxic and side effects between the two groups of drugs after the treatment of lung adenocarcinoma (P<0.05). The median survival time of patients was 16 months in the icotinib group and 10 months in the pemetrexed group, with a statistically significant difference (P<0.05). The 1-year survival rate was higher in the icotinib group than that in the pemetrexed group (P<0.05). There was no difference in 2- and 3-year survival rates between the two groups (P>0.05). In conclusion, the clinical efficacy of icotinib is similar to that of pemetrexed in the treatment of lung adenocarcinoma, but icotinib has less adverse reactions, with better improvement in disease control.

Strategies to overcome acquired resistance to EGFR TKI in the treatment of non-small cell lung cancer

Epidermal growth factor receptor tyrosine kinase inhibitor (EGFR TKI) represents a paradigm shift in the treatment of non-small cell lung cancer (NSCLC) patients and has been the first-line therapy in clinical practice. While erlotinib, gefitinib and afatinib have achieved superior efficacy in terms of progression-free survival and overall survival compared with conventional chemotherapy in NSCLC patients, most people inevitably develop acquired resistance to them, which presents another challenge in the treatment of NSCLC. The mechanisms of acquired resistance can be classified as three types: target gene mutation, bypass signaling pathway activation and histological transformation. And the most common mechanism is T790M which accounts for approximately 50% of all subtypes. Many strategies have been explored to overcome the acquired resistance to EGFR TKI. Continuation of EGFR TKI beyond progressive disease is confined to patients in asymptomatic stage when the EGFR addiction is still preserved in some subclones. While the combination of EGFR TKI and chemotherapy or other targeted agents has improved the survival benefit in EGFR TKI resistant patients, there are controversies within them. The next-generation EGFR TKI and immunotherapy represent two novel directions for overcoming acquired resistance and have achieved promising efficacy. Liquid biopsy provides surveillance of the EGFR mutation by disclosing the entire genetic landscape but tissue biopsy is still indispensable because of the considerable rate of false-negative plasma.

Larger tumors are associated with inferior progression-free survival of first-line EGFR-tyrosine kinase inhibitors and a lower abundance of EGFR mutation in patients with advanced non-small cell lung cancer

BACKGROUND

The impact of primary tumor size on the therapeutic outcomes of EGFR-tyrosine kinase inhibitors (TKIs) in advanced non-small cell lung cancer (NSCLC) with EGFR mutation remains unclear.

METHODS

A total of 291 consecutive patients with advanced EGFR-mutant NSCLC administered first-line EGFR-TKIs were enrolled. Computed tomography was used to assess primary tumor diameter. The amplification refractory mutation system plus was used to quantitatively evaluate the abundance of EGFR mutations. Associations between depth of response, abundance of EGFR mutations, and tumor size was investigated.

RESULTS

Patients were divided into three groups according to T classification: ≤ 3 cm (n = 109), 3-5 cm (n = 121), and > 5 cm (n = 61). Median progression-free survival (PFS) was significantly longer in the ≤ 3 cm and 3-5 cm groups compared to the > 5 cm group (10.8 vs. 10.5 vs. 7.1 months; P < 0.001). Subgroup analysis revealed a consistent result in patients with exon 19 deletion and 21 L858R mutation. Multivariate analysis revealed that tumor size was an independent predictive factor for PFS (hazard ratio 1.528, 95% confidence interval 1.104-2.115; P = 0.010). Larger tumors (> 5 cm) were marginally significantly less EGFR-mutant abundant than smaller tumors (≤ 5 cm) (mean ± standard deviation 30.5 ± 29.5% vs. 45.8 ± 43.1%; P = 0.08).

CONCLUSION

Larger tumors (> 5 cm) were associated with inferior PFS of first-line EGFR-TKI therapy in advanced NSCLC patients with activating EGFR mutations. A potential explaination might be that EGFR mutations are less abundant in larger tumors.

Thick-wall cavity predicts worse progression-free survival in lung adenocarcinoma treated with first-line EGFR-TKIs

BACKGROUND

Cavity occurs in 5.7 to 14.9% of patients with lung adenocarcinoma (ADC). However, the impact of cavity on the therapeutic response to epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) in ADC patients with EGFR mutations remains unclear. The aim of the present retrospective study was to elucidate the incidence and detailed characteristics of EGFR-mutant cavitary ADC and investigate the efficacy of EGFR-TKI treatment in this subgroup.

METHODS

Two hundred seventy-six consecutive patients with advanced EGFR-mutant lung ADC treated with first-line EGFR-TKIs were enrolled. Cavitation and the thickness of cavity wall were assessed based on high-resolution computed tomography scans. Progression-free survival (PFS) was analyzed by the Kaplan-Meier plots and the log-rank test was used to calculate the significance between groups.

RESULTS

Cavity occurred in 5.4% (15/276) of patients with EGFR-mutant lung ADC and was more prevalent among male patients (66.7% vs. 33.3%, P = 0.008). Of the 15 EGFR-mutant cavitary ADC, 9 patients had exon 19 deletion (19DEL) and 6 harbored L858R mutation, 9 patients had thick-wall cavity while 6 had thin-wall cavity. Cavity had an adverse impact on the PFS of EGFR-mutant ADC treated with first-line EGFR-TKIs (noncavity versus cavity, 11.0 versus 6.5 months, hazard ratio [HR]: 0.33, 95% confidence interval [CI], 0.15-0.73, P = 0.003). The impaired effect was only observed in patients with L858R mutation (11.0 vs. 4.2 months, HR: 0.05, 95%CI, 0.01-0.27, P = 0.0003) but not in those with 19DEL (10.4 versus 9.7 months, HR: 0.73, 95%CI, 0.30-1.75, P = 0.483). All six L858R-mutant cavitary ADC patients had thick-wall cavity while thick-wall cavity was only identified in one thirds (3/9) of patients with 19DEL. Further analyses showed that patients with thick-wall cavity had worse PFS (6.0 versus 11.0 months, P = 0.013). Multivariate analysis identified cavity as an independent predictive factor for PFS (HR: 0.49, 95% CI, 0.26-0.90, P = 0.022).

CONCLUSION

Cavitary ADC was associated with a worse PFS of first-line EGFR-TKI therapy, mainly in those with L858R mutation. Thick-wall cavity formation may be the main cause that contribute to the worse PFS.

Lung cancer in never smokers-the East Asian experience

Approximately one third of all lung cancer patients in East Asia are never-smokers. Furthermore, the proportion of lung cancer in never smokers (LCINS) has been increasing over time. Never-smokers are more often diagnosed with adenocarcinoma in East Asia, a subtype largely defined by oncogenic drivers. In this subgroup of patients, as high as 90% of patients have been found to harbor well-known oncogenic mutations and can be successfully managed with targeted therapies inhibiting specific oncogenic mutant kinases. EGFR tyrosine kinase inhibitor (EGFR-TKI) treatment has been the most important targeted therapy in lung adenocarcinoma from East Asian never-smokers as approximately 70% of these patients have the opportunity to receive EGFR-TKI treatment. Lung squamous cell carcinoma (SQCC) and small cell lung cancer (SCLC) are two common histologic types of smoking-related non-small cell lung cancer (NSCLC). The proportion of never-smokers with SQCC and SCLC in East Asian patients seems to be higher than that in Caucasian patients. Recent studies also suggest that lung SQCC and SCLC in never-smokers may be distinct subtypes. Therefore, better understanding of the biologic characteristics of these subtypes of patients may provide new insights for the treatment. In this review, we will provide an overview of East Asian experience in the treatment of advanced, never-smoking lung cancer, focusing on etiologic factors in the development of LCINS, targeted therapy for never-smokers with adenocarcinoma, distinct characteristics of never-smokers with lung SQCC and SCLC, and the role of immunotherapy in never-smokers with NSCLC.

Consolidative Local Ablative Therapy Improves the Survival of Patients With Synchronous Oligometastatic NSCLC Harboring EGFR Activating Mutation Treated With First-Line EGFR-TKIs

INTRODUCTION

The aim of the current study was to investigate whether consolidative local ablative therapy (LAT) can improve the survival of patients with stage IV EGFR-mutant NSCLC who have oligometastatic disease treated with first-line EGFR-tyrosine kinase inhibitor (TKI) therapy.

METHODS

Patients with stage IV EGFR-mutant NSCLC and no more than five metastases within 2 months of diagnosis were identified. All patients were treated with first-line EGFR-TKIs. Consolidative LAT included radiotherapy, surgery, or both. Overall survival (OS) and progression-free survival (PFS) were estimated by Kaplan-Meier curves.

RESULTS

From October 2010 to May 2016, 145 patients were enrolled, including 51 (35.2%) who received consolidative LAT to all oligometastatic sites (all-LAT group), 55 (37.9%) who received consolidative LAT to either primary tumor or oligometastatic sites (part-LAT group), and 39 (26.9%) who did not receive any consolidative LAT (non-LAT group). The median PFS in all-LAT, part-LAT, and non-LAT groups were 20.6, 15.6, and 13.9 months, respectively (p < 0.001). The median OS in all-LAT, part-LAT, and non-LAT groups were 40.9, 34.1, and 30.8 months, respectively (p < 0.001). The difference was statistically significant between the all-LAT group and part-LAT or non-LAT group but was not between the part-LAT and non-LAT group. The median OS was significantly improved with consolidative LAT for primary tumor (40.5 versus 31.5 months, p < 0.001), brain metastases (38.2 versus 29.2 months, p = 0.002), and adrenal metastases (37.1 versus 29.2 months, p = 0.032). Adverse events (grade ≥ 3) due to radiotherapy included pneumonitis (7.7%) and esophagitis (16.9%).

CONCLUSIONS

The current study showed that consolidative LAT to all metastatic sites was a feasible option for patients with EGFR-mutant oligometastatic NSCLC during first-line EGFR-TKI treatment, with significantly improved PFS and OS compared with consolidative LAT to partial sites or observation alone.

EGFR-TKIs in non-small-cell lung cancer: focus on clinical pharmacology and mechanisms of resistance

The clinical introduction of EGFR-TKIs within the oncologic armamentarium has changed the therapeutic landscape of non-small-cell lung cancer (NSCLC) creating widespread expectations both in patients and clinicians. However, several gaps in current understanding leave open important questions regarding the use of these drugs in clinical practice. For instance, there is uncertainty in regard to which EGFR-TKI should be given first in naive patients with EGFR-driven malignancies since different generations of drugs are available with different pharmacological profiles. Furthermore, acquired drug resistance may limit the therapeutic potential of EGFR-TKIs and the choice of the best treatment strategy after first-line treatment failure is still debated. This review article is aimed at describing the pharmacological properties of EGFR-TKIs and the current treatment options for NSCLC patients who develop acquired resistance. This information might be useful to design new rational and more effective pharmacological strategies in patients with EGFR-mutant NSCLC.