Predictive efficacy of 11C‐PD153035 PET imaging for EGFR–tyrosine kinase inhibitor sensitivity in non‐small cell lung cancer patients

To determine the correlation of ¹¹C‐PD153035 uptake with epidermal growth factor receptor‐tyrosine kinase inhibitor (EGFR‐TKI) sensitivity and phosphorylated EGFR (pEGFR) expression in non‐small cell lung cancer (NSCLC) cell lines with different EGFR‐TKI sensitivities and in their corresponding xenografts. Four human NSCLC cell lines (HCC827, PC9, A549, and H1975) in the logarithmic phase were co‐incubated with ¹¹C‐PD153035 to analyze the correlation of ¹¹C‐PD153035 uptake with EGFR‐TKI sensitivity, and EGFR/pEGFR expression. Nude mice xenograft models bearing the four NSCLCs were prepared. ¹¹C‐PD153035 positron‐emission tomography (PET)‐computed tomography (CT) was used to image the xenografts and observe radioactive uptakes. Correlation of the in vivo uptakes with EGFR‐TKI sensitivity, and EGFR/pEGFR expression was analyzed. HCC827 and PC9 cells, which were highly sensitive to EGFR‐TKIs, exhibited higher ¹¹C‐PD153035 uptakes than the other cells. A549 cells, which were moderately sensitive to EGFR‐TKIs, showed higher uptake than the EGFR‐TKI–resistant H1975 cells, which showed little or no uptake. Radioactive uptakes were positively correlated with pEGFR expression in all cells. PET‐CT showed that radioactivity was highest in HCC827 xenografts. The radioactivity in PC9 xenografts was higher than that in A549 and H1975 xenografts. Tumor vs. non‐tumor tissue ratio values were positively correlated with pEGFR expression in HCC827 and PC9 xenografts, but not in A549 and H1975 xenografts. In conclusion, ¹¹C‐PD153035 can serve as an EGFR imaging agent in vitro and in vivo, and predicts sensitivity to EGFR‐TKIs. This will provide an experimental basis for clinical applications of ¹¹C‐PD153035 and individualized NSCLC therapy.     

Safety and efficacy of first‐line dacomitinib in Japanese patients with advanced non‐small cell lung cancer

In a subgroup of Japanese patients in the ARCHER 1050 randomized phase 3 trial, we evaluated the efficacy and safety and determined the effects of dose modifications on adverse events (AE) and therapy management of first‐line oral dacomitinib 45 mg compared with oral gefitinib 250 mg, each once daily in 28‐d cycles, in patients with EGFR‐activating mutation–positive (EGFR‐positive; exon 19 deletion or exon 21 L858R substitution mutations) advanced non‐small cell lung cancer (NSCLC). The primary endpoint was progression‐free survival (PFS; RECIST, version 1.1, by blinded independent review). In 81 Japanese patients (40 dacomitinib, 41 gefitinib), PFS was longer with dacomitinib compared with gefitinib (hazard ratio [HR], 0.544 [95% confidence interval {CI}, 0.307‐0.961]; 2‐sided P = .0327; median 18.2 for dacomitinib [95% CI, 11.0‐31.3] mo, 9.3 [95% CI, 7.4‐14.7] mo for gefitinib). The most common Grade 3 AEs were dermatitis acneiform with dacomitinib (27.5%) and increased alanine aminotransferase with gefitinib (12.2%). A higher proportion of patients receiving dacomitinib (85.0%) compared with gefitinib (24.4%) had AEs leading to dose reduction. Incidence and severity of diarrhea, dermatitis acneiform, stomatitis and paronychia were generally reduced after dacomitinib dose reductions and dacomitinib treatment duration was generally longer in patients with a dose reduction in comparison with those without a dose reduction. Our results confirmed the efficacy and safety of first‐line dacomitinib in Japanese patients with EGFR‐positive advanced NSCLC.     

Impact of tumor microenvironment on the efficacy of epidermal growth factor receptor‐tyrosine kinase inhibitors in patients with EGFR‐mutant non‐small cell lung cancer

We retrospectively investigated the impact of the tumor microenvironment (TME) on the efficacy of epidermal growth factor receptor (EGFR)‐tyrosine kinase inhibitors (TKIs) as first‐line treatment in 70 patients with advanced EGFR‐mutant non‐small cell lung cancer and who were seen at Osaka City University Hospital (Osaka, Japan) between August 2013 and December 2017. Using immunohistochemical staining with 28‐8 and D7U8C Abs, the tumor proportion score was assessed for programmed cell death‐1 ligand‐1 (PD‐L1), as high (50% or more) or low (less than 50%), and ligand‐2 (PD‐L2) expression, respectively. The extent of CD8⁺ tumor‐infiltrating lymphocytes was evaluated on a scale of 0‐3, with 0‐1 as low and 2‐3 as high. The TME of the 52 evaluable pretreatment specimens was categorized into 4 subtypes, according to the respective PD‐L1 tumor proportion and CD8⁺ scores, as follows: (a) high/high (13.5%, n = 7); (b) low/low (42.3%, n = 22); (c) high/low (17.3%, n = 9); and (d) low/high (26.9%, n = 14). Expression of PD‐L2 was significantly the highest in type 1 (57.1% vs 4.5% vs 11.1% vs 7.1%, respectively; P = .0090). Response rate was significantly the lowest in type 1 (14.3% vs 81.8% vs 66.7% vs 78.6%, respectively; P = .0085). Progression‐free survival was the shortest in type 1 and the longest in type 4 (median, 2.4 vs 11.3 vs 8.4 vs 17.5 months, respectively; P = .00000077). The efficacy of EGFR‐TKIs differed according to the TME, and the phenotype with high PD‐L1 and CD8⁺ expression might be the subset that would poorly benefit from such treatment.     

Osimertinib in Japanese patients with EGFR T790M mutation‐positive advanced non‐small‐cell lung cancer: AURA3 trial

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) are the first‐line treatment for patients with EGFR mutant non‐small‐cell lung cancer (NSCLC). However, most patients become resistant to these drugs, so their disease progresses. Osimertinib, a third‐generation EGFR‐TKI that can inhibit the kinase even when the common resistance‐conferring Thr790Met (T790M) mutation is present, is a promising therapeutic option for patients whose disease has progressed after first‐line EGFR‐TKI treatment. AURA3 was a randomized (2:1), open‐label, phase III study comparing the efficacy of osimertinib (80 mg/d) with platinum‐based therapy plus pemetrexed (500 mg/m²) in 419 patients with advanced NSCLC with the EGFR T790M mutation in whom disease had progressed after first‐line EGFR‐TKI treatment. This subanalysis evaluated the safety and efficacy of osimertinib specifically in 63 Japanese patients enrolled in AURA3. The primary end‐point was progression‐free survival (PFS) based on investigator assessment. Improvement in PFS was clinically meaningful in the osimertinib group (n = 41) vs the platinum‐pemetrexed group (n = 22; hazard ratio 0.27; 95% confidence interval, 0.13‐0.56). The median PFS was 12.5 and 4.3 months in the osimertinib and platinum‐pemetrexed groups, respectively. Grade ≥3 adverse events determined to be related to treatment occurred in 5 patients (12.2%) treated with osimertinib and 12 patients (54.5%) treated with platinum‐pemetrexed. The safety and efficacy results in this subanalysis are consistent with the results of the overall AURA3 study, and support the use of osimertinib in Japanese patients with EGFR T790M mutation‐positive NSCLC whose disease has progressed following first‐line EGFR‐TKI treatment. (ClinicalTrials.gov trial registration no. NCT02151981.)     

转化性小细胞肺癌1例分析

我国肺癌发病率及死亡率在恶性肿瘤中居首位[1].肺癌分为小细胞肺癌( small cell lung cancer,SCLC)和非小细胞肺癌(non -small cell lung cancer,NSCLC)[2].NSCLC 包括腺癌、鳞癌及大细胞肺癌.最常见的组织学分类是腺癌,其次是小细胞癌,鳞状细胞癌或神经内分...     

Rebiopsy for patients with non‐small‐cell lung cancer after epidermal growth factor receptor‐tyrosine kinase inhibitor failure

Although third‐generation epidermal growth factor receptor‐tyrosine kinase inhibitors (EGFR‐TKI) can overcome T790M‐mediated resistance in non‐small‐cell lung cancer (NSCLC), rebiopsy to confirm T790M status is occasionally difficult. We aimed to investigate the current tendency and the limitations of rebiopsy in clinical practice. This study included 139 consecutive NSCLC patients with EGFR mutations, who had experienced progressive disease (PD) after EGFR‐TKI treatment. We retrospectively reviewed patient characteristics, tumor progression sites and rebiopsy procedures. Of 120 patients (out of the original 139) who were eligible for clinical trials, 75 (63%) underwent rebiopsy for 30 pleural effusions, 32 thoracic lesions, four bone, two liver, and seven at other sites. Rebiopsy procedures included 30 thoracocentesis, 24 transbronchial biopsies, 13 computed tomography (CT)‐guided needle biopsies and 8 other procedures. Of the 75 rebiopsied patients, 71 (95%) were pathologically diagnosed with malignancy; and 34 (45%) had available tissue samples for EGFR analyses. Of the 75 biopsied patients, 61 (81%) were analyzed for EGFR mutation, using tissue or cytology samples; T790M mutations were identified in 20 (33%) of the 61 patients. Of the 120 patients, 45 (38%) did not undergo rebiopsy, because of inaccessible tumor sites (n = 19), patient refusal (n = 6) or decision of physician (n = 10). In conclusion, among patients with EGFR mutations who had PD after EGFR‐TKI treatment, 63% underwent rebiopsy. Most rebiopsy samples were diagnosed with malignancy. However, tissue samples were less available and T790M mutations were identified less frequently than in previous studies. Skill and experience with rebiopsy and noninvasive alternative methods will be increasingly important.     

RAC1 inhibition as a therapeutic target for gefitinib‐resistant non‐small‐cell lung cancer

Although epidermal growth factor receptor (EGFR)‐tyrosine kinase inhibitors (EGFR‐TKI), including gefitinib, provide a significant clinical benefit in non‐small‐cell lung cancer (NSCLC) patients, the acquisition of drug resistance has been known to limit the efficacy of EGFR‐TKI therapy. In this study, we demonstrated the involvement of EGF‐EGFR signaling in NSCLC cell migration and the requirement of RAC1 in EGFR‐mediated progression of NSCLC. We showed the significant role of RAC1 pathway in the cell migration or lamellipodia formation by using gene silencing of RAC1 or induction of constitutive active RAC1 in EGFR‐mutant NSCLC cells. Importantly, the RAC1 inhibition suppressed EGFR‐mutant NSCLC cell migration and growth in vitro, and growth in vivo even in the gefitinib‐resistant cells. In addition, these suppressions by RAC1 inhibition were mediated through MEK or PI3K independent mechanisms. Collectively, these results open up a new opportunity to control the cancer progression by targeting the RAC1 pathway to overcome the resistance to EGFR‐TKI in NSCLC patients.     

ASP8273 tolerability and antitumor activity in tyrosine kinase inhibitor‐naïve Japanese patients with EGFR mutation‐positive non‐small‐cell lung cancer

Epidermal growth factor receptor (EGFR) activating mutations occur in approximately 50% of East Asian patients with non‐small‐cell lung cancer (NSCLC) and confer sensitivity to tyrosine kinase inhibitors (TKIs). ASP8273 is an irreversible EGFR‐TKI, given orally, that inhibits EGFR activating mutations and has shown clinical activity in patients with EGFR mutation‐positive NSCLC. Epidermal growth factor receptor‐TKI‐naïve Japanese adult patients (≥20 years) with NSCLC harboring EGFR mutations were enrolled in this open‐label, single‐arm, phase II study (ClinicalTrials.gov identifier NCT02500927). Patients received ASP8273 300 mg once daily until discontinuation criteria were met. The primary end‐point was to determine the safety of ASP8273 300 mg; the secondary end‐point was antitumor activity defined by RECIST version 1.1. Thirty‐one patients (12 men and 19 women; median age, 64 years [range, 31‐82 years]) with EGFR mutation‐positive NSCLC were enrolled; as of 23 February 2016, 25 patients (81%) were still on study. Of the 31 patients, 27 (87%) had an exon 19 deletion (n = 13, 42%) or an L858R (n = 14, 45%) EGFR activating mutation, and two (7%) had an L861Q mutation. Five patients (16%) had other EGFR activating mutations, two had an activating mutation and the T790M resistance mutation. The most commonly reported treatment‐emergent adverse event was diarrhea (n = 24, 77%). All patients had at least one post‐baseline scan; one patient (3%) achieved a confirmed complete response, 13 (42%) had a confirmed partial response, and 15 (48%) had confirmed stable disease (disease control rate, 94% [n = 29/31]) per investigator assessment. Once‐daily ASP8273 at 300 mg was generally well tolerated and showed antitumor activity in TKI‐naïve Japanese patients with EGFR mutation‐positive NSCLC.     

Clinical activity of ASP8273 in Asian patients with non‐small‐cell lung cancer with EGFR activating and T790M mutations

Epidermal growth factor receptor (EGFR)‐activating mutations confer sensitivity to tyrosine kinase inhibitor (TKI) treatment for non‐small‐cell lung cancer (NSCLC). ASP8273 is a highly specific, irreversible, once‐daily, oral, EGFR TKI that inhibits both activating and resistance mutations. This ASP8273 dose‐escalation/dose‐expansion study (NCT02192697) was undertaken in two phases. In phase I, Japanese patients (aged ≥20 years) with NSCLC previously treated with ≥1 EGFR TKI received escalating ASP8273 doses (25‐600 mg) to assess safety/tolerability and to determine the maximum tolerated dose (MTD) and/or the recommended phase II dose (RP2D) by the Bayesian Continual Reassessment Method. In phase II, adult patients with T790M‐positive NSCLC in Japan, Korea, and Taiwan received ASP8273 at RP2D to further assess safety/tolerability and determine antitumor activity, which was evaluated according to Simon's two‐stage design (threshold response = 30%, expected response = 50%, α = 0.05, β = 0.1). Overall, 121 (n = 45 [33W/12M] phase I, n = 76 [48W/28M]) phase 2) patients received ≥1 dose of ASP8273. In phase I, RP2D and MTD were established as 300 and 400 mg, respectively. As 27 of the 63 patients treated with ASP8273 300 mg achieved a clinical response, ASP8273 was determined to have antitumor activity. The overall response rate at week 24 in all patients was 42% (n = 32/76; 95% confidence interval, 30.9‐54.0). Median duration of progression‐free survival was 8.1 months (95% confidence interval, 5.6, upper bound not reached). The most commonly reported treatment‐related adverse event in phase II was diarrhea (57%, n = 43/76). ASP8273 300 mg was generally well tolerated and showed antitumor activity in Asian patients with both EGFR‐activating and T790M mutations.     

Enhanced efficacy of AZD3759 and radiation on brain metastasis from EGFR mutant non‐small cell lung cancer

The prognosis of patients with brain metastasis (BM) is poor. In our study, we demonstrated that AZD3759, an EGFR tyrosine kinase inhibitors (TKIs) with excellent blood–brain barrier (BBB) penetration, combined with radiation enhanced the antitumor efficacy in BM model from EGFR mutant (EGFRm) NSCLC. Besides, the antitumor activity displayed no difference between radiation concurrently with AZD3759 and radiation sequentially with AZD3759. Mechanistically, we found that two factors determined the enhanced efficacy: cells with EGFRm which were sensitive to AZD3759, and a relative high concentration of AZD3759. We have validated mechanisms underlying the radiosensitizing effect of AZD3759, which were involved in decreased cell proliferation and survival, and suppressed repair of DNA damage. Moreover, our study found that AZD3759 inhibited both the non‐homologous end joining (NHEJ) and homologous recombination (HR) DNA double‐strand breaks (DSBs) repair pathway, and abrogated the G2/M checkpoint to suppress DNA damage repair. We also detected the BBB penetration of AZD3759 when combined with cranial radiation. The results showed the BBB penetration of AZD3759 was decreased within 24 hr after radiation, however, the free concentration of AZD3759 in brain kept at a high level in the context of radiation. In conclusion, our findings suggest that AZD3759 combined with radiation enhances the antitumor activity in BM from EGFRm NSCLC, this combination therapy may be an effective treatment option for BM from EGFRm NSCLC.     

Afatinib versus cisplatin plus pemetrexed in Japanese patients with advanced non‐small cell lung cancer harboring activating EGFR mutations: Subgroup analysis of LUX‐Lung 3

In LUX‐Lung 3, afatinib significantly improved progression‐free survival (PFS) versus cisplatin/pemetrexed in EGFR mutation‐positive lung adenocarcinoma patients and overall survival (OS) in Del19 patients. Preplanned analyses in Japanese patients from LUX‐Lung 3 were performed. Patients were randomized 2:1 to afatinib or cisplatin/pemetrexed, stratified by mutation type (Del19/L858R/Other). Primary endpoint was PFS (independent review). Secondary endpoints included OS, objective response, and safety. Median PFS (data cut‐off: February 2012) for afatinib versus cisplatin/pemetrexed was 13.8 vs 6.9 months (hazard ratio [HR], 0.38; 95% confidence interval [CI], 0.20–0.70; P = 0.0014) in all Japanese patients (N = 83), with more pronounced improvements in those with common mutations (Del19/L858R; HR, 0.28; 95% CI, 0.15–0.52; P < 0.0001) and Del19 mutations (HR, 0.16; 95% CI, 0.06–0.39; P < 0.0001). PFS was also improved in L858R patients (HR, 0.50; 95% CI, 0.20–1.25; P = 0.1309). Median OS (data cut‐off: November 2013) with afatinib versus cisplatin/pemetrexed was 46.9 vs 35.8 months (HR, 0.75; 95% CI, 0.40–1.43; P = 0.3791) in all Japanese patients, with greater benefit in patients with common mutations (HR, 0.57; 95% CI, 0.29–1.12; P = 0.0966) and Del19 mutations (HR, 0.34; 95% CI, 0.13–0.87; P = 0.0181); OS was not significantly different in L858R patients (HR, 1.13; 95% CI, 0.40–3.21; P = 0.8212). Following study treatment discontinuation, most patients (93.5%) received subsequent anticancer therapy. The most common treatment‐related adverse events were diarrhea, rash/acne, nail effects and stomatitis with afatinib and nausea, decreased appetite, neutropenia, and leukopenia with cisplatin/pemetrexed. Afatinib significantly improved PFS versus cisplatin/pemetrexed in Japanese EGFR mutation‐positive lung adenocarcinoma patients and OS in Del19 but not L858R patients ( www.clinicaltrials.gov ; NCT00949650).     

Management of acquired resistance to epidermal growth factor receptor kinase inhibitors in patients with advanced non‐small cell lung cancer

The widespread adoption of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors for the first‐line treatment of patients with advanced EGFR‐mutated non‐small cell lung cancer has resulted in acquired tyrosine kinase inhibitor resistance becoming a ubiquitous clinical problem. The identification of specific mechanisms of acquired resistance has allowed a better understanding of the biology and natural history of resistant disease, but is only now starting to impact treatment decisions. Strategies for managing acquired resistance in patients with advanced non‐small cell lung cancer are complex and must be adapted to the individual characteristics of each patient's cancer. Although combination chemotherapy is the presumed standard of care for most patients, prospective trial data are lacking, highlighting the importance of offering patients participation in clinical trials in this setting. Emerging data from trials of third‐generation mutant‐specific EGFR kinase inhibitors suggests particular promise with this class of agents. Cancer 2014;120:2289–2298. © 2014 American Cancer Society.     

Osimertinib in patients with epidermal growth factor receptor T790M advanced non‐small cell lung cancer selected using cytology samples

Osimertinib is a potent, irreversible epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) selective for EGFR‑TKI sensitizing (EGFRm) and T790M resistance mutations. The primary objective of the cytology cohort in the AURA study was to investigate safety and efficacy of osimertinib in pretreated Japanese patients with EGFR T790M mutation‐positive non‐small cell lung cancer (NSCLC), with screening EGFR T790M mutation status determined from cytology samples. The cytology cohort was included in the Phase I dose expansion component of the AURA study. Patients were enrolled based on a positive result of T790M by using cytology samples, and received osimertinib 80 mg in tablet form once daily until disease progression or until clinical benefit was no longer observed at the discretion of the investigator. Primary endpoint for efficacy was objective response rate (ORR) by investigator assessment. Twenty‐eight Japanese patients were enrolled into the cytology cohort. At data cut‐off (February 1, 2016), 12 (43%) were on treatment. Investigator‐assessed ORR was 75% (95% confidence interval [CI] 55, 89) and median duration of response was 9.7 months (95% CI 3.8, not calculable [NC]). Median progression‐free survival was 8.3 months (95% CI 4.2, NC) and disease control rate was 96% (95% CI 82, 100). The most common all‐causality adverse events were paronychia (46%), dry skin (46%), diarrhea (36%) and rash (36%). Osimertinib provided clinical benefit with a manageable safety profile in patients with pretreated EGFR T790M mutation‐positive NSCLC whose screening EGFR T790M mutation‐positive status was determined from cytology samples. (ClinicalTrials.gov number NCT01802632).     

Osimertinib for Japanese patients with T790M‐positive advanced non‐small‐cell lung cancer: A pooled subgroup analysis

Epidermal growth factor receptor (EGFR)‐tyrosine kinase inhibitors (TKIs) are the standard of care for non‐small‐cell lung cancer (NSCLC) patients harboring EGFR mutations. However, almost all patients develop resistance after approximately 1 y of treatment, with >50% of cases due to the T790M secondary mutation of the EGFR gene. A large global Phase III study (AURA3) demonstrated that osimertinib significantly prolonged progression‐free survival (PFS) over platinum‐doublet chemotherapy in patients with T790M‐positive NSCLC who had progressed on previous EGFR‐TKI therapy. However, it is not clear whether efficacy or safety of osimertinib in Japanese patients is similar to the overall population. We report a pre‐planned subgroup analysis of pooled Phase II data from the AURA Extension and AURA2 trials to investigate the efficacy and safety of osimertinib in Japanese patients. This study included 81 Japanese patients. Patients were administered 80 mg osimertinib orally once daily until disease progression. The main endpoints were objective response rate (ORR), PFS, and safety. The ORR was 63.6% and median PFS was 13.8 mo. Overall survival rate at 36 mo was 54.0%. The most common all‐cause adverse events (AEs) were rash (grouped term; 65.4%), diarrhea (51.9%), paronychia (grouped term; 49.4%), and dry skin (grouped term; 39.5%). Most AEs were grade 1‐2. Five patients (6.2%) developed interstitial lung disease, resulting in two deaths (2.5%). Osimertinib demonstrated favorable ORR and PFS in Japanese patients, similar to the overall population. Additionally, osimertinib has good efficacy and a manageable safety profile in Japanese patients with NSCLC who had acquired resistance due to the T790M mutation.     

EGFR-TKI治疗非小细胞肺癌的耐药机制进展研究

肺癌的发病率和死亡率已居我国恶性肿瘤的第一位。以表皮生长因子受体,酪氨酸激酶为靶点的酪氨酸激酶抑制剂(EGFR-TKI)治疗肺癌已广泛引起关注。但部分患者在服用EGFR-TKI初期即出现原发耐药,有些患者在服用EGFR-TKI一段时间后产生继发性耐药,本文综述EGFR-TKl分子耐药机制的研究现状,探讨EGFR-TKl分子耐药机制重要的临床意义。      

Combined inhibition of MEK and PI3K pathways overcomes acquired resistance to EGFR‐TKIs in non‐small cell lung cancer

Compensatory activation of the signal transduction pathways is one of the major obstacles for the targeted therapy of non‐small cell lung cancer (NSCLC). Herein, we present the therapeutic strategy of combined targeted therapy against the MEK and phosphoinositide‐3 kinase (PI3K) pathways for acquired resistance to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) in NSCLC. We investigated the efficacy of combined trametinib plus taselisib therapy using experimentally established EGFR‐TKI‐resistant NSCLC cell lines. The results showed that the feedback loop between MEK/ERK and PI3K/AKT pathways had developed in several resistant cell lines, which caused the resistance to single‐agent treatment with either inhibitor alone. Meanwhile, the combined therapy successfully regulated the compensatory activation of the key intracellular signals and synergistically inhibited the cell growth of those cells in vitro and in vivo. The resistance mechanisms for which the dual kinase inhibitor therapy proved effective included (MET) mesenchymal‐epithelial transition factor amplification, induction of epithelial‐to‐mesenchymal transition (EMT) and EGFR T790M mutation. In further analysis, the combination therapy induced the phosphorylation of p38 MAPK signaling, leading to the activation of apoptosis cascade. Additionally, long‐term treatment with the combination therapy induced the conversion from EMT to mesenchymal‐to‐epithelial transition in the resistant cell line harboring EMT features, restoring the sensitivity to EGFR‐TKI. In conclusion, our results indicate that the combined therapy using MEK and PI3K inhibitors is a potent therapeutic strategy for NSCLC with the acquired resistance to EGFR‐TKIs.