EGFR-TKIs Gefitinib Research Articles

Postprogression Outcomes for Osimertinib versus Standard-of-Care EGFR-TKI in Patients with Previously Untreated EGFR-mutated Advanced Non-Small Cell Lung Cancer.

In the phase III FLAURA study, third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) osimertinib significantly improved progression-free survival (PFS) versus standard-of-care (SoC) EGFR-TKI (gefitinib or erlotinib) in patients with previously untreated EGFR (exon 19 deletion or L858R) mutation-positive advanced non-small cell lung cancer (NSCLC). Interim overall survival (OS) data were encouraging, but not formally statistically significant at current maturity (25%). Here we report exploratory postprogression outcomes. Patients were randomized 1:1 to receive osimertinib (80 mg orally, once daily) or SoC EGFR-TKI (gefitinib 250 mg or erlotinib 150 mg, orally, once daily). Treatment beyond disease progression was allowed if the investigator judged ongoing clinical benefit. Patients receiving SoC EGFR-TKI could cross over to receive osimertinib after independently confirmed objective disease progression with documented postprogression T790M-positive mutation status. At data cutoff (June 12, 2017), 138 of 279 (49%) and 213 of 277 (77%) patients discontinued osimertinib and SoC EGFR-TKI, respectively, of whom 82 (59%) and 129 (61%), respectively, started a subsequent treatment. Median time to discontinuation of any EGFR-TKI or death was 23.0 months [95% confidence interval (CI), 19.5-not calculable (NC)] in the osimertinib arm and 16.0 months (95% CI, 14.8-18.6) in the SoC EGFR-TKI arm. Median second PFS was not reached (95% CI, 23.7-NC) in the osimertinib arm and 20.0 months (95% CI, 18.2-NC) in the SoC EGFR-TKI arm [hazard ratio (HR), 0.58; 95% CI, 0.44-0.78; P = 0.0004]. All postprogression endpoints showed consistent improvement with osimertinib versus SoC EGFR-TKI, providing further confidence in the interim OS data.

Reciprocal interaction of HOTAIR and SP1 together enhance the ability of Xiaoji decoction and gefitinib to inhibit EP4 expression

Ethnopharmacological relevanceThe Chinese herbal prescription Xiaoji decoction (XJD) has long been used for cancer treatment. However, the molecular mechanisms underlying the effects of this medicine, particularly to enhance the efficiency of EGFR-TKI in the treatment of lung cancer have not been well elucidated. Materials and methodsCell viability and cell cycle distribution were detected by MTT assay and flow cytometry, respectively. The phosphorylation of ERK1/2 and protein levels of SP1 and EP4 were determined by Western blot. The expression of the HOX transcript antisense RNA (HOTAIR) was measured by qRT-PCR. Transient transfection experiments were used to overexpress the HOTAIR, SP1 and EP4 genes. The interaction between HOTAIR and SP1 were further examined via RNA immunoprecipitation (RIP) assay. A tumor xenograft model was used to confirm the in vitro findings. ResultsWe showed that XJD inhibited growth and induced cell arrest of human non-small cell lung cancer (NSCLC) cells. We also found that XJD increased the phosphorylation of ERK1/2 and inhibited levels of HOTAIR and SP1, EP4 proteins, which were blocked by inhibitor of MEK/ERK. There was reciprocal interaction between HOTAIR and SP1. Silencing of HOTAIR reduced EP4 protein levels and repressed the growth of NSCLC cells, while overexpression of HOTAIR and SP1 overcame XJD-reduced EP4 protein expression. Additionally, excessive expressed EP4 reversed the effect of XJD on cell growth. Importantly, there was synergy of XJD with another cancer treatment drug, EGFR-TKI gefitinib, in this process. We also found that XJD inhibited tumor growth in a xenograft nude mice model. ConclusionsOur results show that XJD inhibits NSCLC cell growth via ERK1/2-mediated reciprocal repression of HOTAIR and SP1 protein expression, followed by reduced EP4 gene expression. XJD and gefitinib exhibit synergy in this process. The in vitro and in vivo study provides a novel mechanism by which XJD enhances the growth inhibitory effect of gefitinib in gefitinib-resistant NSCLC cells.

First- and Second-Generation EGFR-TKIs Are All Replaced to Osimertinib in Chemo-Naive EGFR Mutation-Positive Non-Small Cell Lung Cancer?

Activating mutations of the epidermal growth factor receptor gene (EGFR) are a driving force for some lung adenocarcinomas. Several randomized phase III studies have revealed that treatment with first- or second-generation EGFR tyrosine kinase inhibitors (TKIs) results in an improved progression-free survival (PFS) compared to standard chemotherapy in chemonaive patients with advanced non–small cell lung cancer (NSCLC), selected based on the presence of EGFR mutations. Patients treated with second-generation EGFR-TKIs have also shown an improved PFS relative to those treated with first-generation EGRF-TKIs. Osimertinib is a third-generation EGFR-TKI that still irreversibly inhibits the activity of EGFR after it has acquired the secondary T790M mutation that confers resistance to first- and second-generation drugs. Its efficacy has been validated for patients whose tumors have developed T790M-mediated resistance, as well as for first-line treatment of those patients with EGFR mutation–positive NSCLC. Although there are five EGFR-TKIs (gefitinib, erlotinib, afatinib, dacomitinib, and osimertinib) currently available for the treatment of EGFR-mutated lung cancer, the optimal sequence for administration of these drugs remains to be determined. In this review, we addressed this issue with regard to maximizing the duration of the EGFR-TKI treatment.

Frequency and clinical significance of NF1 mutation in lung adenocarcinomas from East Asian patients.

NF1 is a tumor suppressor gene that negatively regulates Ras signaling. NF1 deficiency plays an important role in carcinogenesis. To investigate the frequency and clinical significance of NF1 mutation, we examined mutation status of NF1, TP53, LKB1 and RB1 in 704 surgically resected lung adenocarcinomas from East Asian patients using semiconductor-based Ion Torrent sequencing platform. Common driver events, including mutations in EGFR, KRAS, HER2, BRAF, MET, and fusions affecting ALK, RET and ROS1, were also concurrently detected. The correlation between NF1 mutations and clinicomolecular features of patients was further evaluated. Among 704 patients, 42 NF1 mutations were found in 33 patients (33/704, 4.7%), including 14 patients harboring EGFR/NF1 comutations (14/33, 42.4%). Comparing with EGFR-mutant patients, patients harboring NF1 mutations were closely associated with solid component subtype (p = 0.028). Comparing with KRAS mutations, NF1 mutations were found more common in female and never smokers (p = 0.003 and p = 0.004, respectively). Kaplan-Meier survival analysis revealed that patients harboring NF1 mutation had similar disease-free survival (DFS) and overall survival (OS) with patients with KRAS mutation. Although frequently overlapped with EGFR mutation, patients harboring NF1 mutation had significantly shorter DFS (p = 0.019) and OS (p = 0.004) than patients with EGFR mutation. During follow-up, one female patient with EGFR exon 19 deletion and NF1 Q1815X comutation showed poor response to EGFR TKIs (Gefitinib and Osimertinib) after disease relapse. In conclusion, NF1 mutations define a unique molecular and clinicopathologic subtype of lung adenocarcinoma. Examination of NF1 mutation may contribute to molecular subtyping and therapeutic intervention of lung adenocarcinoma.

Abstract B27: Osimertinib (AZD9291) is sensitive and bound with affinity to EGFR exon 20 insertion mutant models

Abstract Background: Although EGFR exon 20 insertion mutation is the third most common among EGFR-mutant NSCLC, this mutation has not been well studied and the first-generation EGFR TKIs are ineffective. In addition, the efficacy of the third-generation EGFR TKIs is controversial. Methods: Various EGFR exon 20 insertion mutation models were developed using Ba/F3 system as follows: C-helix (n=1, A763_Y764insFQEA) and loop following C-helix (n=7). In addition, SNU-3173 cell line was derived from NSCLC patient with EGFR exon 20 insertion mutation. Cell viability assays were performed using EGFR TKIs (gefitinib, erlotinib, dacomitinib, afatinib, rociletinib, olmutinib, nazartinib, and osimertinib). Immunoblotting was performed to evaluate the downstream signals of EGFR pathway. Additionally, the docking homology models of EGFR exon 20 insertion mutations with osimertinib were developed with SWISS-Model and SwissDock for estimation of the structural appropriateness. Results: Cell viability assay showed that EGFR exon 20 insertion mutants are resistant to the first-generation EGFR TKIs, except for A763_Y764insFQEA mutant Ba/F3 cells. IC50 values of second-generation EGFR TKIs are five- to hundreds-folds lower than gefitinib and erlotinib. Dacomitinib and afatinib have good efficacy for the most of them, and regulated down signaling pathways. The third-generation TKIs showed moderate efficacy against EGFR exon 20 insertion mutants. Overall, osimertinib has the most successful inhibition of EGFR exon 20 insertion mutants (IC50 values for C-helix and loop following C-helix mutants for afatinib, <0.1nM and 16.7-352.5nM; rociletinib 1022.1nM and 288.0-3034.6nM; olmutinib, 351.8nM and 30.4-626.7nM; osimertinib 131.6nM and 14.7-65.7nM; and nazartinib, 351.8nM and 36.3-509.9nM, respectively). Ribbon diagram with in silico homology docking simulations showed how exon 20 insertion mutations change the structures of kinase domain and the suitable binding values with various EGFR exon 20 insertion mutant subtypes with osimertinib. Conclusions: Osimertinib showed an outstanding effectiveness against various EGFR exon 20 insertion mutations. In addition, docking simulation of in silico homology models corresponded with the in vitro results. Consequently, osimertinib is effective against EGFR exon 20 insertion mutant models. Citation Format: Yusoo Lee, Tae Min Kim, Dong-Wan Kim, Yong-Oon Ahn, Soyeon Kim, Bhumsuk Keam, Miso Kim, Dae Seog Heo. Osimertinib (AZD9291) is sensitive and bound with affinity to EGFR exon 20 insertion mutant models [abstract]. In: Proceedings of the Fifth AACR-IASLC International Joint Conference: Lung Cancer Translational Science from the Bench to the Clinic; Jan 8-11, 2018; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(17_Suppl):Abstract nr B27.

CNS Response to Osimertinib Versus Standard Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors in Patients With Untreated EGFR-Mutated Advanced Non-Small-Cell Lung Cancer.

Purpose We report CNS efficacy of osimertinib versus standard epidermal growth factor receptor ( EGFR) tyrosine kinase inhibitors (TKIs) in patients with untreated EGFR-mutated advanced non-small-cell lung cancer from the phase III FLAURA study. Patients and Methods Patients (N = 556) were randomly assigned to osimertinib or standard EGFR-TKIs (gefitinib or erlotinib); brain scans were not mandated unless clinically indicated. Patients with asymptomatic or stable CNS metastases were included. In patients with symptomatic CNS metastases, neurologic status was required to be stable for ≥ 2 weeks after completion of definitive therapy and corticosteroids. A preplanned subgroup analysis with CNS progression-free survival as primary objective was conducted in patients with measurable and/or nonmeasurable CNS lesions on baseline brain scan by blinded independent central neuroradiologic review. The CNS evaluable-for-response set included patients with ≥ one measurable CNS lesion. Results Of 200 patients with available brain scans at baseline, 128 (osimertinib, n = 61; standard EGFR-TKIs, n = 67) had measurable and/or nonmeasurable CNS lesions, including 41 patients (osimertinib, n = 22; standard EGFR-TKIs, n = 19) with ≥ one measurable CNS lesion. Median CNS progression-free survival in patients with measurable and/or nonmeasurable CNS lesions was not reached with osimertinib (95% CI, 16.5 months to not calculable) and 13.9 months (95% CI, 8.3 months to not calculable) with standard EGFR-TKIs (hazard ratio, 0.48; 95% CI, 0.26 to 0.86; P = .014 [nominally statistically significant]). CNS objective response rates were 91% and 68% in patients with ≥ one measurable CNS lesion (odds ratio, 4.6; 95% CI, 0.9 to 34.9; P = .066) and 66% and 43% in patients with measurable and/or nonmeasurable CNS lesions (odds ratio, 2.5; 95% CI, 1.2 to 5.2; P = .011) treated with osimertinib and standard EGFR-TKIs, respectively. Probability of experiencing a CNS progression event was consistently lower with osimertinib versus standard EGFR-TKIs. Conclusion Osimertinib has CNS efficacy in patients with untreated EGFR-mutated non-small-cell lung cancer. These results suggest a reduced risk of CNS progression with osimertinib versus standard EGFR-TKIs.

Abstract 3922: Ganetespib demonstrates strong anti-tumor effect in acquired EGFR-TKI resistance NSCLC cells

Abstract Purpose: Epidermal growth factor receptor (EGFR) -tyrosine kinase inhibitors (TKIs) are the standard first-line treatment of advanced non-small cell lung cancer (NCSLC). However, almost all patients eventually acquire resistance to EGFR-TKIs, and novel therapeutic strategies to overcome the acquired resistance have been required. Heat-shock protein 90 (Hsp90) is a chaperon protein involved in folding and stabilization of client proteins essential for cancer cell growth and survival. Ganetespib (STA-9090) is one of the second-generation Hsp90 inhibitors with strong anti-tumor effect on NSCLC cells. In this study, we evaluated the anti-tumor effect of ganetespib in EGFR-TKI sensitive and acquired resistance NSCLC cell lines. Materials and Methods: We treated 4 EGFR-mutant NSCLC cell lines (HCC827, HCC4006, PC-9 and HCC4011), and 14 experimentally established EGFR-TKIs (gefitinib or afatinib) resistance cell lines with ganetespib. The EGFR-TKI resistance mechanism consisted of EGFR T790M second mutation, MET amplification, epithelial-to-mesenchymal transition (EMT) and cancer stem cell-like features. We determined cell proliferation by MTS assay and calculated the IC50 values. We also performed Western blotting to investigate downstream signaling pathways. Results: The IC50 values in parental NSCLC cell lines ranged from 1.3nM to 15nM, and those in acquired EGFR-TKI resistant cell lines ranged from 0.87nM to 25nM, which suggests strong anti-tumor effect of ganetespib. In addition, this effect was observed regardless of the resistant mechanisms, including EMT. Ganetespib suppressed EGFR activation in EGFR-TKI resistance cells harboring EGFR T790M second mutation. Also, ganetespib suppressed MET activation in EGFR-TKI resistance cells harboring MET amplification. Conclusion: Ganetespib showed strong anti-tumor effect in acquired EGFR-TKI resistance NSCLC cells regardless of the resistant mechanisms, suggesting that ganetespib could be a promising therapeutic option in the treatment of NSCLC with acquired EGFR-TKI resistance. Citation Format: Eisuke Kurihara, Kazuhiko Shien, Hidejiro Torigoe, Yuta Takahashi, Yusuke Ogoshi, Takahiro Yoshioka, Kei Namba, Hiroki Sato, Hiromasa Yamamoto, Junichi Soh, Shinichi Toyooka. Ganetespib demonstrates strong anti-tumor effect in acquired EGFR-TKI resistance NSCLC cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3922.

Abstract CT013: Osimertinib displays high brain exposure in healthy subjects with intact blood-brain barrier: a microdose positron emission tomography (PET) study with 11C-labelled osimertinib

Abstract Introduction. Osimertinib is a third generation, CNS active, epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) used for treatment of patients with locally advanced and metastatic T790M mutation positive non-small cell lung cancer (NSCLC). Osimertinib has shown efficacy superior to that of EGFR-TKIs (erlotinib and gefitinib) in the first-line treatment of EGFR mutation-positive advanced NSCLC and with reduced risk of CNS progression (Soria et al 2017). Furthermore, rapid osimertinib response on brain metastases has been reported (Koba et al 2017). Preliminary examination in non-human primates using 11C-labeled osimertinib indicates penetration of the intact blood brain barrier (BBB) and a high brain exposure compared to other EGFR-TKI agents, which may potentially contribute to improved efficacy in patients with brain metastases compared to other TKIs (Ballard et al 2016). Aim. The aim of this positron emission tomography (PET) study was to measure the brain exposure of [11C]osimertinib administered intravenously in healthy volunteers with an intact BBB. Methods. Eight male healthy volunteers (age 52±8 years) were examined for ~90 minutes with PET after single intravenous microdose of [11C]osimertinib. Concentration of [11C]osimertinib was also measured in arterial and venous blood and plasma. Brain MRI was acquired and used for co-registration of the PET data and automatic delineation of regions of interest in the brain. PK parameters Cmax (brain), Tmax (brain) and AUC0-90 min brain/blood ratio were calculated. Results. In all healthy volunteers, [11C]osimertinib distributed to the brain rapidly, with mean Tmax=13 min (range 5-30 min), Cmax= 1.4±0.3 SUV (range 1-1.8) corresponding to 2.2±0.2% of injected radioactivity and AUC0-90 min brain/blood ratio=3.8±0.3 (range 3.3-4.1). [11C]Osimertinib was distributed in all regions of the brain with uptake being highest in putamen followed by thalamus, frontal cortex, temporal cortex, caudate, cerebellum and white matter. Conclusions. This study indicates that [11C]osimertinib has a good brain exposure in human subjects with intact BBB and may potentially contribute to the efficacy of treatment with osimertinib. In NSCLC, patients with brain metastasis may benefit from treatment with osimertinib due to favorable brain exposure of the drug. Future studies in patients with NSCLC are required to examine uptake and kinetic properties of [11C]osimertinib in brain metastases.

Treatment of EGFR mutation-positive non-small cell lung cancer complicated by Trousseau syndrome with gefitinib followed by osimertinib: a case report.

Malignant tumors can induce a hypercoagulable state known as Trousseau syndrome that increases the risk for venous thromboembolism including disabling cerebral infarction. Anticoagulant therapy without anticancer treatment is not effective for amelioration of this coagulation abnormality. Most patients with lung cancer positive for activating mutations of the epidermal growth factor receptor (EGFR) are sensitive to EGFR tyrosine kinase inhibitors (TKIs), but the efficacy and safety of EGFR-TKIs in such patients with a poor performance status (PS) due to Trousseau syndrome has been unclear. We here describe a patient with EGFR mutation–positive lung cancer who developed disabling cerebral infarction due to Trousseau syndrome. Administration of the EGFR-TKI gefitinib and anticoagulant therapy resulted in a partial tumor response and recovery from both the coagulation abnormality and the severe neurological symptoms. After the development of resistance to gefitinib, the EGFR-TKI osimertinib was safely administered until disease progression without recurrence of the coagulation abnormality. This case suggests that gefitinib followed by osimertinib may be a safe and effective treatment option for patients with EGFR mutation–positive lung cancer who experience disabling cerebral infarction due to Trousseau syndrome.

Abstract A158: Characterization of antitumor activity of TAS6417, a novel EGFR-TKI targeting exon 20 insertions

Abstract Background: Activating mutations in the EGFR gene are important targets in cancer therapy because they are key drivers of NSCLC. EGFR-TKIs (gefitinib, erlotinib and afatinib) are eligible for first-line therapy in NSCLC patients with EGFR activating mutations such as exon 19 deletions and L858R. However, NSCLC driven by EGFR exon 20 insertions, the third most common mutation in the EGFR gene, are associated with poor clinical response to the existing EGFR-TKI therapies, suggesting an unmet medical need for these patients. TAS6417 (previously termed TPC-064) is a novel EGFR inhibitor that has a potent inhibitory activity against exon 20 insertions while sparing wild-type (WT) EGFR, and could be an efficacious treatment option for these patients without the risk of severe diarrhea associated with inhibition of WT EGFR. Materials and Methods: Tumor growth analysis was conducted in athymic nude mice or nude rats bearing a patient-derived xenograft (PDX) (LXF2478, an NSCLC harboring EGFR V769_D770insASV mutation), or genetically engineered cells expressing EGFR exon 20 insertions (NCI-H1975 EGFR D770_N771insSVD and NIH-3T3 EGFR H773_V774insNPH). The protein and phosphoprotein expression level in tumors were determined by Western blot analysis. Results: TAS6417 was discovered as a more potent and selective inhibitory activity on the EGFR harboring exon 20 insertions compared to WT. The effect of TAS6417 on antitumor activity was evaluated in subcutaneously implantation model in nude mice and nude rats, and also in orthotopic lung implantation in nude mice. In sc mouse models, once-daily dosing of TAS6417 at 50 mg/kg or more inhibited tumor growth of genetically engineered cell lines, NCI-H1975 EGFR D770_N771insSVD (expressing exon 20 insertion mutation instead of endogenous L858R/T790M mutations) and NIH-3T3 EGFR N773_V774insNPH. Furthermore, a PDX harboring EGFR V769_D770insASV showed a striking response to TAS6417, resulting in tumor regression at 100 mg/kg. In nude rats bearing NCI-H1975 EGFR D770_N771insSVD xenografts, TAS6417 inhibited tumor growth at 10 mg/kg or more, and tumor shrinkage was observed at 40 mg/kg without any effect on body weight gain. Furthermore, TAS6417 provided a survival benefit with good tolerability in lung orthotopic implantation mouse model. Pharmacodynamics marker analysis revealed that TAS6417 inhibited EGFR signaling including both AKT and ERK pathways in tumors, leading to caspase activation with an increase in Bim protein expression. Conclusions: These findings demonstrated that TAS6417 had potent antitumor activity with good tolerability in not only genetically engineered xenografts but also in a PDX harboring EGFR exon 20 insertions, suggesting a promising therapeutic option for patients with NSCLC harboring EGFR exon 20 insertions. Citation Format: Shinichi Hasako, Miki Terasaka, Ryoto Fujita, Naomi Abe, Akihiro Hashimoto, Kenichi Matsuo, Teruhiro Utsugi, Yoshikazau Iwasawa. Characterization of antitumor activity of TAS6417, a novel EGFR-TKI targeting exon 20 insertions [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr A158.

Cancer-associated fibroblasts promote epithelial-mesenchymal transition and EGFR-TKI resistance of non-small cell lung cancers via HGF/IGF-1/ANXA2 signaling

The involvement of the tumor stromal cells in acquired resistance of non-small cell lung cancers (NSCLCs) to tyrosine kinase inhibitors (TKIs) has previously been reported, but the precise mechanism remains unclear. In the present study, we investigated the role and mechanism underlying Cancer-associated fibroblasts (CAFs) in TKI resistance of NSCLCs. In vitro and in vivo experiments showed that HCC827 and PC9 cells, non-small cell lung cancer cells with EGFR-activating mutations, became resistant to the EGFR-TKI gefitinib when cultured with CAFs isolated from NSCLC tissues. Moreover, we showed that CAFs could induce epithelial-mesenchymal transition (EMT) phenotype of HCC827 and PC9 cells, with an associated change in the expression of epithelial to mesenchymal transition markers. Using proteomics-based method, we identified that CAFs significantly increased the expression of the Annexin A2 (ANXA2). More importantly, knockdown of ANXA2 completely reversed EMT phenotype and gefitinib resistance induced by CAFs. Furthermore, we found that CAFs increased the expression and phosphorylation of ANXA2 by secretion of growth factors HGF and IGF-1 and by activation of the corresponding receptors c-met and IGF-1R. Dual inhibition of HGF/c-met and IGF-1/IGF-1R pathways could significantly suppress ANXA2, and markedly reduced CAFs-induced EMT and gefitinib resistance. Taken together, these findings indicate that CAFs promote EGFR-TKIs resistance through HGF/IGF-1/ANXA2/EMT signaling and may be an ideal therapeutic target in NSCLCs with EGFR-activating mutations.

A phase I trial of afatinib and bevacizumab in chemo-naïve patients with advanced non-small-cell lung cancer harboring EGFR mutations: Okayama Lung Cancer Study Group Trial 1404

ObjectiveIn advanced epidermal growth factor receptor (EGFR)-mutant non-small-cell lung cancer (NSCLC), treatment with afatinib, a second-generation EGFR-tyrosine kinase inhibitor (TKI), confers a significant survival benefit over platinum-based chemotherapy. The first-generation EGFR-TKIs gefitinib and erlotinib in combination with bevacizumab have improved progression-free survival. We hypothesized that the combination of afatinib with bevacizumab would further improve efficacy, and conducted a phase I trial to test this hypothesis. Materials and methodsUntreated patients with advanced EGFR-mutant NSCLC were enrolled. The primary endpoint was safety. Two doses of afatinib, 40mg/day (level 0) and 30mg/day (level −1), were evaluated in combination with 15mg/kg bevacizumab every 3 weeks. Optimal dosing was determined by dose-limiting toxicity (DLT), with the concentration at which ≤4 of 12 patients experienced toxicity considered the recommended dose. ResultsNineteen patients were enrolled (level 0:5, level −1:14). Three of the five patients at level 0 experienced a DLT, which indicated that this dose was unfeasible. Three patients at level −1 developed a DLT of grade 3 non-hematological toxicity, which was soon resolved. Grade 3 or worse adverse events were experienced by all five patients at dose level 0 (diarrhea in 2, skin rash in 1, hypoxia in 1, and paronychia in 1), and by three patients at level −1 (diarrhea in 2 and anorexia in 1). Among 16 evaluable patients, 1 had a complete response, 12 had partial responses, and 0 had progressive disease. ConclusionAfatinib plus bevacizumab (level −1) was well tolerated and showed evidence of favorable disease control. This combination therapy may represent a potent therapeutic option for patients with EGFR-mutant NSCLC.

PL 04.02 Where We Are Now, and Where We Will Be in 10 years: From Asian Perspective

PL 04.02 Where We Are Now, and Where We Will Be in 10 years: From Asian Perspective

PPARγ agonist efatutazone and gefitinib synergistically inhibit the proliferation of EGFR-TKI-resistant lung adenocarcinoma cells via the PPARγ/PTEN/Akt pathway

Development of acquired resistance to EGFR-TKI therapy continues to be a serious clinical problem in Lung adenocarcinoma management. Peroxisome proliferator-activated receptor gamma (PPARγ) agonists demonstrate anti-tumor activity likely via transactivating genes that regulate cell proliferation, differentiation and apoptosis. Efatutazone, a novel later generation PPARγ agonist, selectively activates PPARγ target genes and has antiproliferative effects in a range of malignancies. However, the exact function and molecular mechanism of PPARγ agonists efatutazone in EGFR-TKI gefitinib-resistance of Lung adenocarcinoma has not been determined. In this study, we studied the development of acquired resistance to an EGFR-TKI gefitinib in lung adenocarcinoma cells and investigated the antiproliferative effects of efatutazone in the acquired resistant cells. The treatment of gefitinib-resistant cells with efatutazone reduced the growth of gefitinib-resistant cells in a dose- and time-dependent manner, and facilitated the anti-proliferative effects of gefitinib. Mechanistic investigations suggested that efatutazone acted by upregulating protein expression of PPARγ, phosphatase and tensin homolog (PTEN), inactivating the Akt pathway, followed by dephosphorylation of p21Cip1 at Thr145 without affecting the transcriptional levels. Our results suggested that efatutazone, alone or in combination with gefitinib, might offer therapeutic effects in lung adenocarcinoma.

Abstract 103: Blockage of Cdc7/CDK9 signaling sensitizes triple negative breast cancer to EGFR-targeted therapy

Abstract The treatment of Triple-Negative Breast Cancer (TNBC) still represents a profound clinical challenge, the disease being disproportionately responsible for breast cancer-associated deaths. As a consequence, the identification of targeted agents, which synergize with current therapeutic options, is paramount. Resistance to EGFR-tyrosine kinase inhibitors (TKIs), despite frequent EGFR overexpression and reliance on downstream signalling pathways in TNBC, remains endemic. Recent data has also suggested that kinase-inhibition of EGFR in itself is insufficient, given the kinase-independent functions of the protein in transcriptional regulation and DNA-repair may permit prolonged EGFR-mediated signalling in the presence of inhibitors. We performed a kinase inhibitor drug screen (378 kinase inhibitors targeting ~40 different cancer-related kinases) to identify synergistic activity with EGFR inhibition in TNBC. We demonstrate that the dual cdc7/CDK9 inhibitor PHA-767491 synergizes with multiple EGFR-TKIs (Erlotinib, Gefitinib and Lapatinib) in vitro to overcome resistance to EGFR-targeted therapy in various TNBC cell lines. Combined inhibition of EGFR and cdc7/CDK9 resulted in reduced cell proliferation, accompanied by induction of apoptosis and G2-M cell cycle-arrest. Combination therapy inhibited crucial components of the DNA-replicative machinery and also proteins involved in CDK9-mediated transcriptional elongation. Moreover, higher expression of cdc7 and POLR2A was found to be significantly correlated with poorer survival rates in breast cancer patients. Additionally, this synergistic combination effectively inhibited the growth of cells isolated from patient-derived TNBC xenografts under ex vivo culture conditions, highlighting the utility of targeting common transcriptional nodes in cancers addicted to growth factor-mediated signalling pathways. Citation Format: Ronan P. McLaughlin, Jichao He, Vera van der Noord, Jevin Redel, Marcel Smid, Lambert Dorssers, John Martens, John Foekens, Yinghui Zhang, Bob van de Water. Blockage of Cdc7/CDK9 signaling sensitizes triple negative breast cancer to EGFR-targeted therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 103. doi:10.1158/1538-7445.AM2017-103

The first- or second-line use of pemetrexed sequentially with EGFR-TKI did not differ in PFS for advanced NSCLC patients harboring EGFR-mutant tumors.

e20531 Background: Both EGFR-TKI and pemetrexed doublet chemotherapy (P) are two effective therapies in advanced NSCLC patients with EGFR mutant tumors. But which one should be used in first-line remains controversial. Methods: This was a retrospective study where patients prescribed with EGFR-TKI (gefitinib or icotinib) from Jan 2013 to Jan 2016 were screened. Patients must have metastastic diseases harboring TKI-sensitizing EGFR mutation. They must be older than 18 years, and have evaluable target lesions. Whether TKI or P was used in the first line, it must be switched to the other in the second line. PFS in both first line (PFS1) and second line (PFS2) was collected. Results: We screened totally 550 patients (gefitinib n = 455, icotinib n = 95) to enroll a cohort of 36 patients. They were all adenocarcinoma except 1 adenosquamous carcinoma. Gender (M or F), PS (0 or 1), mutation type (Exon19Ddel or other) were equally distributed. The median age was 50.5 years. For the whole cohort, the total PFS (PFS1+PFS2) was 18.1 m (95%CI: 15.2-21.1 m). For those (n = 24) receiving first-line TKI, PFS1, PFS2, and total PFS were 10.3 m, 6.6 m, and 19.2 m. And for those receiving first-line P (n = 12), they were were 3.4 m, 11.5 m, and 16.5m. The total PFS in both groups did not differ significantly (p = 0.548). Conclusions: Our results argued the sequential usage of TKI and P achieve a comparable PFS irrespective of the sequence.

Exploratory cohort study and meta-analysis of BIM deletion polymorphism in patients with epidermal growth factor receptor-mutant non-small-cell lung cancer treated with epidermal growth factor receptor tyrosine kinase inhibitors.

BackgroundNon-small-cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) mutations might develop primary and secondary resistance to tyrosine kinase inhibitors (TKIs). The proapoptotic protein Bcl-2-like 11 (BIM) is a key modulator of apoptosis triggered by EGFR-TKIs. The recent studies have indicated that some patients with positive EGFR mutations were refractory to EGFR-TKIs if they harbored a BIM deletion polymorphism. The purpose of this study was to investigate whether BIM polymorphism predicts treatment efficacy of EGFR-TKIs in Chinese NSCLC patients.Patients and methodsA cohort of advanced NSCLC patients with EGFR mutations and treated with EGFR-TKIs (gefitinib or erlotinib) were recruited. We drew peripheral blood to determinate BIM deletion status and then compared patients’ clinical outcomes according to the BIM deletion status. Additionally, we electronically searched eligible cohort studies and conducted a meta-analysis to pool event risk.ResultsThe exploratory cohort study included 140 patients. Patients with and without the BIM deletion polymorphism had similar objective response rates (ORRs, 48.5 vs 63.0%, P=0.16), disease control rate (DCR, 93.9 vs 97.0%, P=0.60) and adverse reactions. Similar progression-free survival (PFS) and overall survival (OS) were noted in overall population (P=0.27 for PFS and P=0.61 for OS) and prespecified patient subgroups. The meta-analysis included 10 eligible cohort studies involving 1,317 NSCLC patients. It showed the positive BIM deletion was associated with shorter PFS (hazard ratio =1.45; P=0.02). Nonsignificant differences existed for ORR, DCR and OS.ConclusionThe expanded meta-analysis results demonstrated the positive BIM deletion predicts shorter PFS in NSCLC patients after treatment with EGFR-TKIs while other clinical measures do not. A large multicenter well-designed cohort study involving other concurrent genetic alterations is warranted.

MA08.05 Depth of Response to First-Line EGFR TKI Does Not Predict Survival in EGFR-Mutated NSCLC Patients

The association between depth of response to EGFR TKI and prognosis of EGFR-mutated NSCLC remains unclear. We aimed to assess the correlation between maximal tumor shrinkage and survival in patients treated with gefitinib and afatinib. Patients with advanced EGFR-mutated NSCLC enrolled in first-line gefitinib and afatinib clinical trials between 2005 and 2014 at the National Taiwan University Hospital were reviewed. Patients who had at least one measurable target lesion that shrank during treatment were included. Overall survival (OS) was defined as time from date of enrollment to death or May 30th, 2016. Correlation between tumor shrinkage and OS was analyzed by Pearson correlation coefficient and Kaplan-Meier method. The influence of high maximal tumor shrinkage (defined as ≥50% tumor shrinkage), age, gender, types of EGFR mutation, central nervous system (CNS) involvement at diagnosis, CNS as site of progression, first-line EGFR TKI (gefitinib or afatinib), and subsequent treatments (chemotherapy, third-generation TKI) on OS was evaluated by a multivariate Cox proportional hazard model. A total of 189 trial patients were screened and 91 patients were eligible for analysis (gefitinib n=42, afatinib n=49). The median maximal tumor shrinkage during first-line EGFR TKI treatment was 53% (interquartile range 30.5%). Maximal tumor shrinkage did not correlate with OS in all patients (R2=0.0225, p=0.169), and either the gefitinib (R2=0.0036, p=0.689) or afatinib (R2=0.0625, p=0.085) group (Fig.1A). High maximal tumor shrinkage also did not significantly affect OS (HR 0.86, 95% CI 0.54-1.40, p=0.564) (Fig. 1B). In multivariate analysis, CNS as site of progression (HR 2.96, 95% CI 1.39-6.29, p=0.005) and first-line afatinib (HR 0.51, 95% CI 0.29-0.91, p=0.022) were the only factors that significantly influenced OS. The depth of response to first-line gefitinib and afatinib was not predictive of OS in patients with EGFR-mutated NSCLC.

SC05.03 Novel Tyrosine Kinase Inhibitors in Lung Cancer

SC05.03 Novel Tyrosine Kinase Inhibitors in Lung Cancer

OA23.05 First-Line Afatinib versus Gefitinib in EGFRm+ Advanced NSCLC: Updated Overall Survival Analysis of LUX-Lung 7

The irreversible ErbB family blocker afatinib and the reversible EGFR TKI gefitinib are approved for first-line treatment of advanced EGFRm+ NSCLC. This Phase IIb trial prospectively compared afatinib versus gefitinib in this setting. LUX-Lung 7 assessed afatinib (40 mg/day) versus gefitinib (250 mg/day) in treatment-naïve patients with stage IIIb/IV NSCLC harboring a common EGFR mutation (Del19/L858R). Co-primary endpoints were PFS (independent review), time to treatment failure (TTF) and OS. Other endpoints included ORR and AEs. In case of grade ≥3/selected grade 2 drug-related AEs the afatinib dose could be reduced to 30 mg or 20 mg (minimum). The primary analysis of PFS/TTF was undertaken after ∼250 PFS events. The primary OS analysis was planned after ∼213 OS events and a follow-up period of ≥32 months. 319 patients were randomized (afatinib: 160; gefitinib: 159). At the time of primary analysis, PFS (HR [95% CI] 0.73 [0.57‒0.95], p=0.017), TTF (0.73 [0.58‒0.92], p=0.007) and ORR (70 vs 56%, p=0.008) were significantly improved with afatinib versus gefitinib. The most common grade ≥3 AEs were diarrhea (13%) and rash/acne (9%) with afatinib and elevated ALT/AST (9%) with gefitinib. 42% of patients treated with afatinib had ≥1 dose reduction due to AEs; dose reductions were more common in females than males (77%/23%) and non-Asians than Asians (64%/36%). Dose reduction of afatinib did not negatively impact PFS (<40mg vs ≥40mg; HR [95% CI]: 1.34 [0.90‒2.00]) but reduced incidence and severity of drug-related grade ≥3 AEs. Treatment discontinuation due to drug-related AEs was the same in each arm (6%). The data cut-off for primary OS analysis occurred on 8 April 2016. At this time, median treatment duration (range) was 13.7 (0‒46.4) versus 11.5 (0.5‒48.7) months with afatinib and gefitinib. 25% (afatinib) and 13% (gefitinib) of patients received treatment for >24 months. 73% and 77% of patients in the afatinib and gefitinib arms had ≥1 subsequent systemic anti-cancer treatment, with 46% and 56% receiving a subsequent EGFR-TKI including osimertinib (14%)/olmutinib (14%). OS data, including subgroup analysis with respect to subsequent therapy will be presented at the meeting. Afatinib significantly improved PFS, TTF and ORR versus gefitinib in EGFRm+ NSCLC patients, with a manageable AE profile and few drug-related discontinuations. Dose adjustment of afatinib reduced drug-related AEs without compromising efficacy. Primary OS analysis will be reported.