Antitumor Efficacy of Dual Blockade of EGFR Signaling by Osimertinib in Combination With Selumetinib or Cetuximab in Activated EGFR Human NCLC Tumor Models

PPP3CB overexpression mediates EGFR TKI resistance in lung tumors via calcineurin/MEK/ERK signaling

Despite initial high response rates to first-line EGFR TKI, all non-small-cell lung cancer (NSCLC) with EGFR-activating mutation will ultimately develop resistance to treatment. Identification of resistance mechanisms is critical to adapt treatment and improve patient outcomes. Here, we show that a PPP3CB transcript that encodes full-length catalytic subunit 2B of calcineurin accumulates in EGFR-mutant NSCLC cells with acquired resistance against different EGFR TKIs and in post-progression biopsies of NSCLC patients treated with EGFR TKIs. Neutralization of PPP3CB by siRNA or inactivation of calcineurin by cyclosporin A induces apoptosis in resistant cells treated with EGFR TKIs. Mechanistically, EGFR TKIs increase the cytosolic level of calcium and trigger activation of a calcineurin/MEK/ERK pathway that prevents apoptosis. Combining EGFR, calcineurin, and MEK inhibitors overcomes resistance to EGFR TKI in both in vitro and in vivo models. Our results identify PPP3CB overexpression as a new mechanism of acquired resistance to EGFR TKIs, and provide a promising therapeutic approach for NSCLC patients that progress under TKI treatment.

Lesion-Adaptative Bionic Tracheal Stent with Local Paclitaxel Release for Enhanced Therapy of Tracheal Tumor and Stenosis

The efficacy of tracheal stents (TSs) in treating malignant tracheal stenosis is often compromised by tumor overgrowth, leading to restenosis and other stent-related complications that conventional chemotherapy and commercial stents fail to adequately address. Drug-loaded tracheal stents have the potential to deliver chemotherapeutics directly to tumors while relieving stenosis, but their effectiveness has yet to be studied in vivo. The design of drug-loaded tracheal stents adapting to lesions to achieve optimal antitumor effects and minimal side effects remains an area worth exploring. In this study, a lesion-adaptive bionic tracheal stent (PTX-TS) designed for the dual purpose of treating tracheal tumors and associated stenosis was developed. This novel PTX-TS was evaluated using an orthotopic rabbit model of malignant tracheal stenosis, newly established in this study. The rabbit lesions were precisely scanned using computed tomography (CT) for 3D reconstruction, enabling the design of a PTX-TS that fit both the tumor and airway dimensions to ensure complete tumor coverage and effective dilation of the stenotic airway. The PTX-TS featured a bilayer structure including a surface layer of PTX/ethylene-vinyl acetate copolymer (EVA) blends for sustained PTX release and an inner layer of polycaprolactone (PCL)/EVA blends for appropriate mechanical performance. The stent was fabricated layer by layer using a custom-built 3D printer, and the drug-loaded surface layer was printed using a novel liquid printing technique developed in our lab, achieving a high drug loading of up to 80%. The dose of the PTX-TS was investigated and set as 7.5 mg/cm2, which leads to maximum tissue permeation. With its bionic cross-sectional C-shaped structure, the PTX-TS demonstrated excellent radial flexibility, allowing successful implantation at the lesion site using a specially designed delivery apparatus, where it self-expanded to relieve stenosis. Additionally, the PTX-TS effectively delivered PTX directly to the tracheal tumor, resulting in superior antitumor efficacy without significant toxicity or complications.

ITGB1 and DDR activation as novel mediators in acquired resistance to osimertinib and MEK inhibitors in EGFR-mutant NSCLC

Osimertinib is a third-generation tyrosine kinase inhibitor clinically approved for first-line treatment of EGFR-mutant non-small cell lung cancer (NSCLC) patients. Although an impressive drug response is initially observed, in most of tumors, resistance occurs after different time and an alternative therapeutic strategy to induce regression disease is currently lacking. The hyperactivation of MEK/MAPKs, is one the most common event identified in osimertinib-resistant (OR) NSCLC cells. However, in response to selective drug pressure, the occurrence of multiple mechanisms of resistance may contribute to treatment failure. In particular, the epithelial-to-mesenchymal transition (EMT) and the impaired DNA damage repair (DDR) pathways are recognized as additional cause of resistance in NSCLC thus promoting tumor progression. Here we showed that concurrent upregulation of ITGB1 and DDR family proteins may be associated with an increase of EMT pathways and linked to both osimertinib and MEK inhibitor resistance to cell death. Furthermore, this study demonstrated the existence of an interplay between ITGB1 and DDR and highlighted, for the first time, that combined treatment of MEK inhibitor with DDRi may be relevant to downregulate ITGB1 levels and increase cell death in OR NSCLC cells.

Taking early preventive interventions to manage the challenging issue of acquired resistance to third-generation EGFR inhibitors

Although the clinical efficacies of third-generation epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) such as osimertinib in the treatment of non-small cell lung cancer (NSCLC) with EGFR-activating mutations are promising, drug-acquired resistance inevitably occurs whether they are used as first-line or second-line treatment. Therefore, managing the acquired resistance to third-generation EGFR-TKIs is crucial in the clinic for improving patient survival. Great efforts have been made to develop potentially effective strategies or regimens for the treatment of EGFR-mutant NSCLC patients after relapse following these TKIs therapies with the hope that patients will continue to benefit from treatment through overcoming acquired resistance. Although this approach, which aims to overcome drug-acquired resistance, is necessary and important, it is a passive practice. Taking preventive action early before disease progression to manage the unavoidable development of acquired resistance offers an equally important and efficient approach. We strongly believe that early preventive interventions using effective and tolerable combination regimens that interfere with the process of developing acquired resistance may substantially improve the outcomes of EGFR-mutant NSCLC treatment with third-generation EGFR-TKIs. Thus, this review focuses on discussing the scientific rationale and mechanism-driven strategies for delaying and even preventing the emergence of acquired resistance to third-generation EGFR-TKIs, particularly osimertinib.

"Sandwich" Strategy to Intensify EGFR Blockade by Concurrent Tyrosine Kinase Inhibitor and Monoclonal Antibody Treatment in Highly Selected Patients

EGFR TKIs are not curative, and targeted resistance inevitably results in therapeutic failure. Additionally, there are numerous uncommon EGFR mutations that are insensitive to EGFR TKIs, and there is a lack of clinical strategies to overcome these limitations. EGFR TKI and mAbs target EGFR at different sites, and a combination regimen for delaying/preventing resistance to targeted therapy or obtaining more intensive inhibition for uncommon mutations at cellular, animal and human levels has been explored. This review critically focuses on a combination strategy for uncommon EGFR mutation-positive NSCLC, and discuss the preclinical data, clinical implications, limitations and future prospects of the combination strategy.

Emerging strategies to overcome resistance to third-generation EGFR inhibitors

Epidermal growth factor receptor (EGFR), the receptor for members of the epidermal growth factor family, regulates cell proliferation and signal transduction; moreover, EGFR is related to the inhibition of tumor cell proliferation, angiogenesis, invasion, metastasis, and apoptosis. Therefore, EGFR has become an important target for the treatment of cancer, including non-small cell lung cancer, head and neck cancer, breast cancer, glioma, cervical cancer, and bladder cancer. First- to third-generation EGFR inhibitors have shown considerable efficacy and have significantly improved disease prognosis. However, most patients develop drug resistance after treatment. The challenge of overcoming intrinsic and acquired resistance in primary and recurrent cancer mediated by EGFR mutations is thus driving the search for alternative strategies in the design of new therapeutic agents. In view of resistance to third-generation inhibitors, understanding the intricate mechanisms of resistance will offer insight for the development of more advanced targeted therapies. In this review, we discuss the molecular mechanisms of resistance to third-generation EGFR inhibitors and review recent strategies for overcoming resistance, new challenges, and future development directions.

Osimertinib plus Selumetinib in EGFR-Mutated Non-Small Cell Lung Cancer After Progression on EGFR-TKIs: A Phase Ib, Open-Label, Multicenter Trial (TATTON Part B)

BACKGROUND

MEK/ERK inhibition can overcome acquired resistance to osimertinib in preclinical models. Osimertinib [EGFR-tyrosine kinase inhibitor (TKI)] plus selumetinib (MEK1/2 inhibitor) was assessed in the global TATTON study.

METHODS

This multicenter, open-label, phase Ib study expansion cohort enrolled patients (aged ≥18 years) with MET-negative, EGFRm advanced NSCLC who had progressed on EGFR-TKIs. Patients were assigned to one of two cohorts by prior first- or second-generation or T790M-directed EGFR-TKI and received osimertinib 80 mg every day and intermittent selumetinib 75 mg twice a day orally. Safety and tolerability (primary objective) and antitumor activity determined by objective response rate (ORR), and progression-free survival (PFS) using RECIST v1.1 were assessed. Data cutoff: March 4, 2020.

RESULTS

Forty-seven patients received treatment (prior first- or second-generation EGFR-TKI, n = 12; prior T790M-directed EGFR-TKI, n = 35). Forty-four (94%) patients were Asian; 30 (64%) had baseline exon 19 deletion. Most common AEs were diarrhea (89%), decreased appetite (40%), and stomatitis (32%); 11/47 patients (23%) had an AE Grade ≥3 possibly causally selumetinib-related. ORR was 66.7% [95% confidence interval (CI), 34.9-90.1] in the prior first- or second-generation EGFR-TKI group, 22.9% (95% CI, 10.4-40.1) in the prior T790M-directed EGFR-TKI group, and 34.0% (95% CI, 20.9-49.3) overall; median PFS was 15.0 (95% CI, 2.7-33.0), 2.8 (95% CI, 1.6-5.5), and 4.2 months (95% CI, 2.7-7.2), respectively.

CONCLUSIONS

In this small study, AEs and tolerability of osimertinib plus selumetinib were as expected, on the basis of previous studies. The combination demonstrated antitumor activity supportive of further investigation in patients with MET-negative, EGFRm advanced NSCLC who had progressed on a previous EGFR-TKI.

High Circulating Sonic Hedgehog Protein Is Associated With Poor Outcome in EGFR-Mutated Advanced NSCLC Treated With Tyrosine Kinase Inhibitors

Introduction

Growing preclinical evidence has suggested that the Sonic hedgehog (Shh) pathway is involved in resistance to tyrosine kinase inhibitor (TKI) therapy for EGFR-mutated (EGFRm) non-small cell lung cancer (NSCLC). However, little is known concerning the prognostic value of this pathway in this context.

Materials and Methods

We investigated the relationship between plasma levels of Shh and EGFRm NSCLC patients’ outcome with EGFR TKIs. We included 74 consecutive patients from two institutions with EGFRm advanced NSCLC treated by EGFR TKI as first-line therapy. Plasma samples were collected longitudinally for each patient and were analyzed for the expression of Shh using an ELISA assay. The activation of the Shh–Gli1 pathway was assessed through immunohistochemistry (IHC) of Gli1 and RT-qPCR analysis of the transcripts of Gli1 target genes in 14 available tumor biopsies collected at diagnosis (baseline).

Results

Among the 74 patients, only 61 had baseline (diagnosis) plasma samples, while only 49 patients had plasma samples at the first evaluation. Shh protein was detectable in all samples at diagnosis (n = 61, mean = 1,041.2 ± 252.5 pg/ml). Among the 14 available tumor biopsies, nuclear expression of Gli1 was observed in 57.1% (8/14) of patients’ biopsies. Shh was significantly (p < 0.05) enriched in youth (age < 68), male, nonsmokers, patients with a PS > 1, and patients presenting more than 2 metastatic sites and L858R mutation. Higher levels of Shh correlated with poor objective response to TKI, shorter progression-free survival (PFS), and T790M-independent mechanism of resistance. In addition, the rise of plasma Shh levels along the treatment was associated with the emergence of drug resistance in patients presenting an initial good therapy response.

Conclusion

These data support that higher levels of plasma Shh at diagnosis and increased levels of Shh along the course of the disease are related to the emergence of TKI resistance and poor outcome for EGFR-TKI therapy, suggesting that Shh levels could stand both as a prognostic and as a resistance biomarker for the management of EGFR-mutated NSCLC patients treated with EGFR-TKI.

Systematic analysis of the potential off-target activities of osimertinib by computational target fishing

Osimertinib is a third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor used to treat non-small cell lung cancer. However, its off-targets are obscure, and systematic analysis of off-target activities remains to be performed. Here, we identified the off-targets of osimertinib using PharmMapper and DRAR-CPI and analyzed the intersected targets using the GeneMANIA and DAVID servers. A drug-target-pathway network was constructed to visualize the associations. The results showed that osimertinib is associated with 31 off-targets, 40 Kyoto Encyclopedia of Genes and Genomes pathways, and 9 diseases. Network analysis revealed that the targets were involved in cancer and other physiological processes. In addition to EGFR, molecular docking analysis showed that seven proteins, namely Janus kinase 3, peroxisome proliferator-activated receptor alpha, renin, mitogen-activated protein kinases, lymphocyte-specific protein tyrosine kinase, cell division protein kinase 2 and proto-oncogene tyrosine-protein kinase Src, could also be potential targets of osimertinib. In conclusion, osimertinib is predicted to target multiple proteins and pathways, resulting in the formation of an action network via which it exerts systematic pharmacological effects.

Dramatic response to osimertinib combined with crizotinib in EGFR T790 M mutation only in blood and Met amplification only in tumor tissue expressive non-small cell lung cancer: A case report

RATIONALE

Besides the T790 M mutation, it may coexist with bypass pathway activation in real clinical cases for patients with EGFR mutations who resisted to the first- and second-generation tyrosine kinase inhibitors (TKIs) in non-small cell lung cancer (NSCLC). There are limited clinical trial data describing the efficacy of osimertinib combined with MET inhibition in EGFR T790M-mutant NSCLC patients with Met amplification.

PATIENT CONCERNS

A non-smoking 53-year-old male patient with lung adenocarcinoma underwent gefitinib, afatinib, and osimertinib combined with crizotinib treatment and developed different EGFR resistance mutations.

DIAGNOSES

The patient was diagnosed with lung adenocarcinoma (stage cT4N2M0, IIIB). After resistance to the therapy targeting EGFR exon 21 L858R point mutation, T790 M mutation was detected in liquid biopsy and Met amplification was detected via tissue biopsy by next-generation sequencing (NGS).

INTERVENTIONS

The patient received systemic treatments, including chemotherapy, gefitinib, afatinib, and osimertinib combined with crizotinib.

OUTCOMES

The patient died of multisystem organ failure and had an overall survival of 24 months.

LESSONS

Although osimertinib combined with crizotinib therapy showed dramatic tumor shrinkage in both the primary tumor and bone metastasis to an EGFR T790M-mutant NSCLC patient with MET amplification, the progression-free survival (PFS) was only two months.

Emerging Approaches to Overcome Acquired Drug Resistance Obstacles to Osimertinib in Non-Small-Cell Lung Cancer

The pyrimidine core-containing compound Osimertinib is the only epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) from the third generation that has been approved by the U.S. Food and Drug Administration to target threonine 790 methionine (T790M) resistance while sparing the wild-type epidermal growth factor receptor (WT EGFR). It is nearly 200-fold more selective toward the mutant EGFR as compared to the WT EGFR. A tertiary cystein 797 to serine 797 (C797S) mutation in the EGFR kinase domain has hampered Osimertinib treatment in patients with advanced EGFR-mutated non-small-cell lung cancer (NSCLC). This C797S mutation is presumed to induce a tertiary-acquired resistance to all current reversible and irreversible EGFR TKIs. This review summarizes the molecular mechanisms of resistance to Osimertinib as well as different strategies for overcoming the EGFR-dependent and EGFR-independent mechanisms of resistance, new challenges, and a future direction.

Managing Acquired Resistance to Third-Generation EGFR Tyrosine Kinase Inhibitors Through Co-Targeting MEK/ERK Signaling

Although epidermal growth factor receptor (EGFR)-targeted therapy has improved clinical outcomes of patients with advanced non-small-cell lung cancer (NSCLC) carrying activating EGFR mutations, the development of acquired resistance to EGFR tyrosine kinase inhibitors (EGFR-TKIs), including the promising third-generation ones, results in disease progression and has become an unavoidable problem that limits patient long-term benefit. The third-generation EGFR-TKIs, osimertinib and almonertinib, are now approved for the treatment of advanced NSCLC patients harboring activating EGFR mutations (first-line) and/or the resistant T790M mutation (second-line). Clinically, appropriate management of acquired resistance to third-generation EGFR-TKIs will substantially improve their long-term efficacy against EGFR-mutant NSCLC. Recent preclinical and clinical studies suggest that activation of the Ras/Raf/MEK/ERK signaling pathway may be an important resistance mechanism and accordingly co-targeting this pathway effectively overcomes and abrogates acquired resistance to third-generation EGFR-TKIs. This review focuses on discussing the scientific rationale for and potential of co-targeting MEK/ERK signaling in delaying and overcoming acquired resistance to third-generation EGFR-TKIs, particularly osimertinib.

Use of liquid biopsy in monitoring therapeutic resistance in EGFR oncogene addicted NSCLC

Liquid biopsy has emerged as a minimally invasive alternative to tumor tissue analysis for the management of lung cancer patients, especially for epidermal growth factor receptor (EGFR) oncogene addicted tumor. In these patients, despite the clear benefits of tyrosine kinase inhibitors therapy, the development of acquired resistance and progressive disease is inevitable in most cases and liquid biopsy is important for molecular characterization at resistance and, being non-invasive, may be useful for disease monitoring. In this review, the authors will focus on the applications of liquid biopsy in EGFR-mutated non small cells lung cancer at diagnosis, during treatment and at progression, describing available data and possible future scenarios.

Marked synergy by vertical inhibition of EGFR signaling in NSCLC spheroids shows SOS1 is a therapeutic target in EGFR-mutated cancer

Drug treatment of 3D cancer spheroids more accurately reflects in vivo therapeutic responses compared to adherent culture studies. In EGFR-mutated lung adenocarcinoma, EGFR-TKIs show enhanced efficacy in spheroid cultures. Simultaneous inhibition of multiple parallel RTKs further enhances EGFR-TKI effectiveness. We show that the common RTK signaling intermediate SOS1 was required for 3D spheroid growth of EGFR-mutated NSCLC cells. Using two distinct measures of pharmacologic synergy, we demonstrated that SOS1 inhibition strongly synergized with EGFR-TKI treatment only in 3D spheroid cultures. Combined EGFR- and SOS1-inhibition markedly inhibited Raf/MEK/ERK and PI3K/AKT signaling. Finally, broad assessment of the pharmacologic landscape of drug-drug interactions downstream of mutated EGFR revealed synergy when combining an EGFR-TKI with inhibitors of proximal signaling intermediates SOS1 and SHP2, but not inhibitors of downstream RAS effector pathways. These data indicate that vertical inhibition of proximal EGFR signaling should be pursued as a potential therapy to treat EGFR-mutated tumors.

Lung cancer is the leading cause of cancer-related deaths worldwide. In non-smokers, this disease is usually caused by a mutation in a protein found on the surface of a cell, called EGFR. In healthy lung cells, these proteins trigger a chain of chemical signals that tell the cells to multiply. However, faulty forms of EFGR make the cells grow uncontrollably, leading to the formation of tumors.

Current treatments use EGFR inhibitors that block the activity of these proteins. But cancer cells often become resistant to these treatments by activating other types of growth proteins. One way to overcome this resistance has been by targeting the signaling pathways within individual tumors. But since those pathways differ between tumors, it has been challenging to find a single therapy that can treat all drug-resistant cancer cells.

Now, Theard et al. assessed the therapeutic effects of blocking a specific protein inside lung cells, called SOS1, which is involved in growth signaling in all tumor cells. Six different types of human lung cancer cells were used, all of which had faulty forms of EGFR, with three of the cell types showing drug resistance to current therapies. The cancer cells were either exposed to EGFR inhibitors only or to a combination of EGFR and SOS1 inhibitors. The most effective treatment was found to be through combinational therapy, with enhanced killing of drug-resistant cells.

Theard et al. further assessed the effect of combinational therapy using cells kept in two different ways. Cancer cells were either grown in a two-dimensional format, with cells forming a single cell layer, or in a three-dimensional format, where cells were multi-layered and grew on top of each other as self-aggregating spheroids. Combinational therapy treatment was only successful when the cells where grown in a three-dimensional format.

These findings highlight that future drug development studies should give consideration to the way cells are grown, as it can impact the results. They also provide a steppingstone towards tackling drug resistance in lung cancers that arise from EGFR mutations.

MEK or ERK inhibition effectively abrogates emergence of acquired osimertinib resistance in the treatment of epidermal growth factor receptor-mutant lung cancers

BACKGROUND

The majority of patients with non-small cell lung cancer (NSCLC) harboring activating epidermal growth factor receptor (EGFR) mutations respond well to osimertinib (AZD9291), a third-generation, mutation-selective EGFR inhibitor. The current study focuses on determining whether targeting MEK/ERK signaling prevents or delays the development of acquired resistance to osimertinib.

METHODS

Drug effects on cell survival were determined by measuring cell number alterations. Apoptosis was assessed with flow cytometry for the detection of annexin V-positive cells and with Western blotting for protein cleavage. Alterations of proteins in cells were detected with Western blotting. Drug effects on delaying the emergence of osimertinib resistance were evaluated with colony formation in vitro and xenografts in nude mice in vivo.

RESULTS

Osimertinib combined with an MEK or ERK inhibitor synergistically decreased cell survival with enhanced induction of apoptosis in EGFR-mutant NSCLC cells but not in EGFR wild-type NSCLC cells. These combinations were also very effective in killing cell clones with primary intrinsic resistance to osimertinib. Continuous and intermittent pharmacologic inhibition of MEK/ERK signaling delayed the emergence of osimertinib resistance both in vitro and in vivo.

CONCLUSIONS

These results provide strong preclinical evidence in support of targeting MEK/ERK signaling as a strategy for delaying or preventing acquired resistance to osimertinib in the clinic to improve the long-term therapeutic efficacy of osimertinib. From a clinical standpoint, the data support the evaluation of an intermittent treatment schedule of osimertinib in combination with an MEK or ERK inhibitor in patients with EGFR-mutated NSCLC.

Combined Therapeutic Effects of 131I-Labeled and 5Fu-Loaded Multifunctional Nanoparticles in Colorectal Cancer

Background

Owing to its combined effects, the co-delivery of different therapeutics is a promising option for the treatment of cancer. In the present study, tumor-targeting poly(ethylene glycol)-poly(lactic acid) (PEG-PLA) nanoparticles were developed for the transportation of two molecules, namely chemotherapeutic drug 5-fluorouracil (5Fu) and radionuclide iodine-131 (¹³¹I), in a single platform.

Methods

The obtained nanoparticles (Cetuximab [Cet]-PEG-PLA-5Fu-¹³¹I) were spherical (diameter approximately 110 nm) and pH-sensitive. The targeting effect of nanoparticles via Cet was confirmed in colorectal cancer cells using a fluorescent assay. The combined effects of Cet-PEG-PLA-5Fu-¹³¹I on cell viability and apoptosis were evaluated in colorectal cancer cells by Cell Counting Kit-8 and flow cytometry assays.

Results

Blank nanoparticles (Cet-PEG-PLA) showed good biocompatibility, and Cet-PEG-PLA-5Fu-¹³¹I nanoparticles were the most effective in terms of inhibition of cell viability and induction of apoptosis compared with monotherapy using Cet-PEG-PLA-5Fu or Cet-PEG-PLA-¹³¹I. In the xenograft mouse model, compared with using Cet-PEG-PLA-5Fu or Cet-PEG-PLA-¹³¹I alone, Cet-PEG-PLA-5Fu-¹³¹I nanoparticles exhibited prolonged circulation in the blood and accumulation in the tumor, thus resulting in enhanced antitumor efficacy. Additionally, combined radio-chemotherapy with Cet-PEG-PLA-5Fu-¹³¹I nanoparticles was associated with smaller tumor sizes than monotherapy, revealing the superior antitumor effects of Cet-PEG-PLA-5Fu-¹³¹I nanoparticles. These effects were further evidenced by histological and immunohistochemical analyses.

Conclusion

The multifunctional Cet-PEG-PLA-5Fu-¹³¹I nanoparticles are promising candidates for the co-delivery of 5Fu-mediated chemotherapy and ¹³¹I-mediated radiotherapy.

Effectiveness and safety of osimertinib in patients with metastatic EGFR T790M-positive NSCLC: An observational real-world study

Osimertinib showed encouraging efficacy in patients with advanced EGFR T790M-positive NSCLC in previous randomized controlled trials. This real-world study aimed to evaluate the effectiveness and safety of osimertinib in a real-world setting. This observational study (NCT03133234) included 74 patients with metastatic EGFR T790M-positive NSCLC who progressed on prior EGFR TKI therapy and received osimertinib between May 2016 and April 2018 at the Kiang Wu Hospital in Macau. Response rate (RR) and other endpoints (progression-free survival [PFS], overall survival [OS], disease control rate [DCR], stable disease rate, and adverse events) were assessed. Survival data were estimated using the Kaplan-Meier method. All patients had stage IV lung adenocarcinoma and 25.6% had brain metastases; median age was 58 years (range 28-84 years) and 83.8% of patients had received at least three prior lines of treatment. The median duration of osimertinib treatment was 8 months (range, 1-25 months). RR and DCR were 67.5% (95% CI 56.9-78.1) and 79.8% (95% CI 70.7-88.9), respectively, while 12.1% had stable disease. The median PFS was 9.0 months (95% CI 6.7-11.2 months), and the median OS was 12.0 months (95% CI 8.8-15.1 months). Nausea (25.8%) and decreased appetite (20.2%) were the most common adverse events associated with osimertinib treatment. Even though most patients had at least three lines of prior treatment, real-world RR and PFS with osimertinib in this study were consistent with those from randomized controlled trials; no new safety signals were observed.

Treatment of uncommon EGFR mutations in non-small cell lung cancer: new evidence and treatment

Sensitizing mutations in epidermal growth factor receptor (EGFR) are associated with positive responses to anti-EGFR-targeted therapy, leading to a new era of treatment for non-small cell lung cancer (NSCLC). Exon 19 deletions and exon 21 L858R substitutions are the most common mutations, accounting for approximately 90% mutations in NSCLC; these are termed classic mutations and result in high sensitivity to tyrosine kinase inhibitors (TKIs). Other EGFR mutations are termed uncommon EGFR mutations, of which G719X, S768I, L861Q, exon 20 insertions, and complex mutations are the most frequent. G719X, S768I, and L861Q are point mutations and those that exist with complex mutations are sensitive to first-generation TKIs. A prospective analysis demonstrated that afatinib, a second-generation TKI, led to a better prognosis in some patients with NSCLC compared to first-generation TKIs. Chemotherapy used to be the traditional choice for patients carrying exon 20 insertions; however, with the development of novel targeted drugs, the role of chemotherapy is changing. Tremendous progress has also been made in clinical trials on immunotherapy treatment of uncommon EGFR mutations. The treatment for patients with NSCLC harboring uncommon EGFR mutations remains a subject of debate and the sensitivity of uncommon EGFR mutations to TKIs is still unclear. Here, we summarized recent data in the literature and provide an overview of the clinical characteristics, incidence, and outcomes of patients harboring G719X, S768I, L861Q, exon 20 insertions, and complex mutations who were treated with TKIs, chemotherapy, or immunotherapy.

Inhibition of the Hedgehog pathway in lung cancer

Inhibitors of the hedgehog pathway are effective in patients with basal cell carcinoma and a subgroup of patients with medulloblastoma with active hedgehog signaling. Despite preclinical work suggesting otherwise, clinical trials in solid tumors of epithelial origin have not shown added benefit with these drugs. Here, we review the preclinical and clinical data of hedgehog pathway inhibition in the most common histologic types of lung cancer. We focus on highlighting areas of uncertainty, where further research might define a niche for hedgehog pathway inhibition in patients with lung cancer.

Integrin-linked kinase (ILK) and src homology 2 domain-containing phosphatase 2 (SHP2): Novel targets in EGFR-mutation positive non-small cell lung cancer (NSCLC)

BACKGROUND

The activation of multiple signaling pathways jeopardizes the clinical efficacy of EGFR tyrosine kinase inhibitors (TKIs) in EGFR-mutation positive non-small cell lung cancer (NSCLC). Integrin-linked kinase (ILK) regulates the interactions between tumor cells and extracellular environment to activate signaling pathways and promote cell proliferation, migration, and epithelial-mesenchymal transition. Src homology 2 domain-containing phosphatase 2 (SHP2) is essential for receptor tyrosine kinase signaling and mitogen-activated protein kinase (MAPK) pathway activation.

METHODS

We analyzed tumor ILK, β-receptor subunit glycoprotein 130 (gp130), SHP2, and stromal hepatocyte growth factor (HGF) and interleukin-6 (IL-6) mRNA expression in baseline tumor specimens of advanced EGFR-mutation positive NSCLC patients treated with EGFR TKIs.

RESULTS

ILK, when highly expressed, was an independent poor prognostic factor for the progression-free survival of the patients, both in the univariate (hazard ratio [HR for disease progression, 2.49; 95% CI, 1.37-4.52; P = .0020]) and in the multivariate (HR 3.74; 95% CI, 1.33-10.56; P = .0126) Cox regression model. Patients with high SHP2 expression had an almost 13-month shorter progression-free survival (P = .0094) and an 18-month shorter overall survival (P = .0182) in comparison to those with low SHP2 mRNA expression.

INTERPRETATION

The levels of ILK and SHP2 could be predictive for upfront combinatory therapy of EGFR TKIs plus SHP2 or ILK inhibitors. FUND: A grant from La Caixa Foundation, an Instituto de Salud Carlos III grant (RESPONSE, PIE16/00011), an Instituto de Salud Carlos III grant (PI14/01678), a Marie Skłodowska-Curie Innovative Training Networks European Grant (ELBA No 765492) and a Spanish Association Against Cancer (AECC) grant (PROYE18012ROSE).

ERBBal Remedies: Combination Therapy for EGFR-mutant Lung Cancers

Multiple members of the ERBB/HER family of the receptor tyrosine kinases have been implicated in mediating acquired resistance to EGFR inhibitors that are used to treat EGFR-mutant lung cancers. New single agents and combination therapies targeting the ERBB/HER family members are being investigated to either prevent or overcome the emergence of acquired resistance. Clin Cancer Res; 24(22); 5499-501. ©2018 AACR See related article by Romaniello et al., p. 5610.

Hedgehog Signaling in Lung Cancer: From Oncogenesis to Cancer Treatment Resistance

Hedgehog signaling pathway is physiologically activated during embryogenesis, especially in lung development. It is also reactivated in many solid tumors. In lung cancer, Hedgehog pathway is closely associated with cancer stem cells (CSCs). Recent works have shown that CSCs produced a full-length Sonic Hedgehog (Shh) protein, with paracrine activity and induction of tumor development. Hedgehog pathway is also involved in tumor drug resistance in lung cancer, as cytotoxic chemotherapy, radiotherapy, and targeted therapies. This review proposes to describe the activation mechanisms of Hedgehog pathway in lung cancer, the clinical implications for overcoming drug resistance, and the perspectives for further research.