Showing papers on "Osimertinib published in 2018"

Osimertinib in Untreated EGFR-Mutated Advanced Non–Small-Cell Lung Cancer

Abstract: BackgroundOsimertinib is an oral, third-generation, irreversible epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) that selectively inhibits both EGFR-TKI–sensitizing and EGFR T790M resistance mutations. We compared osimertinib with standard EGFR-TKIs in patients with previously untreated, EGFR mutation–positive advanced non–small-cell lung cancer (NSCLC). MethodsIn this double-blind, phase 3 trial, we randomly assigned 556 patients with previously untreated, EGFR mutation–positive (exon 19 deletion or L858R) advanced NSCLC in a 1:1 ratio to receive either osimertinib (at a dose of 80 mg once daily) or a standard EGFR-TKI (gefitinib at a dose of 250 mg once daily or erlotinib at a dose of 150 mg once daily). The primary end point was investigator-assessed progression-free survival. ResultsThe median progression-free survival was significantly longer with osimertinib than with standard EGFR-TKIs (18.9 months vs. 10.2 months; hazard ratio for disease progression or death, 0.46; 95% confi...

Assessment of Resistance Mechanisms and Clinical Implications in Patients With EGFR T790M-Positive Lung Cancer and Acquired Resistance to Osimertinib.

Abstract: Importance Osimertinib mesylate is used globally to treatEGFR-mutant non–small cell lung cancer (NSCLC) with tyrosine kinase inhibitor resistance mediated by theEGFRT790M mutation. Acquired resistance to osimertinib is a growing clinical challenge that is poorly understood. Objective To understand the molecular mechanisms of acquired resistance to osimertinib and their clinical behavior. Design, Setting, and Participants Patients with advanced NSCLC who received osimertinib for T790M-positive acquired resistance to prior EGFR tyrosine kinase inhibitor were identified from a multi-institutional cohort (n = 143) and a confirmatory trial cohort (NCT01802632) (n = 110). Next-generation sequencing of tumor biopsies after osimertinib resistance was performed. Genotyping of plasma cell-free DNA was studied as an orthogonal approach, including serial plasma samples when available. The study and analysis were finalized on November 9, 2017. Main Outcomes and Measures Mechanisms of resistance and their association with time to treatment discontinuation on osimertinib. Results Of the 143 patients evaluated, 41 (28 [68%] women) had tumor next-generation sequencing after acquired resistance to osimertinib. Among 13 patients (32%) with maintained T790M at the time of resistance,EGFRC797S was seen in 9 patients (22%). Among 28 individuals (68%) with loss of T790M, a range of competing resistance mechanisms was detected, including novel mechanisms such as acquiredKRASmutations and targetable gene fusions. Time to treatment discontinuation was shorter in patients with T790M loss (6.1 vs 15.2 months), suggesting emergence of pre-existing resistant clones; this finding was confirmed in a validation cohort of 110 patients with plasma cell-free DNA genotyping performed after osimertinib resistance. In studies of serial plasma levels of mutantEGFR, loss of T790M at resistance was associated with a smaller decrease in levels of theEGFRdriver mutation after 1 to 3 weeks of therapy (100% vs 83% decrease;P = .01). Conclusions and Relevance Acquired resistance to osimertinib mediated by loss of the T790M mutation is associated with early resistance and a range of competing resistance mechanisms. These data provide clinical evidence of the heterogeneity of resistance in advanced NSCLC and a need for clinical trial strategies that can overcome multiple concomitant resistance mechanisms or strategies for preventing such resistance.

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

Abstract: 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.

Management of acquired resistance to EGFR TKI–targeted therapy in advanced non-small cell lung cancer

Abstract: Recent advances in diagnosis and treatment are enabling a more targeted approach to treating lung cancers. Therapy targeting the specific oncogenic driver mutation could inhibit tumor progression and provide a favorable prognosis in clinical practice. Activating mutations of epidermal growth factor receptor (EGFR) in non-small cell lung cancer (NSCLC) are a favorable predictive factor for EGFR tyrosine kinase inhibitors (TKIs) treatment. For lung cancer patients with EGFR-exon 19 deletions or an exon 21 Leu858Arg mutation, the standard first-line treatment is first-generation (gefitinib, erlotinib), or second-generation (afatinib) TKIs. EGFR TKIs improve response rates, time to progression, and overall survival. Unfortunately, patients with EGFR mutant lung cancer develop disease progression after a median of 10 to 14 months on EGFR TKI. Different mechanisms of acquired resistance to first-generation and second-generation EGFR TKIs have been reported. Optimal treatment for the various mechanisms of acquired resistance is not yet clearly defined, except for the T790M mutation. Repeated tissue biopsy is important to explore resistance mechanisms, but it has limitations and risks. Liquid biopsy is a valid alternative to tissue re-biopsy. Osimertinib has been approved for patients with T790M-positive NSCLC with acquired resistance to EGFR TKI. For other TKI-resistant mechanisms, combination therapy may be considered. In addition, the use of immunotherapy in lung cancer treatment has evolved rapidly. Understanding and clarifying the biology of the resistance mechanisms of EGFR-mutant NSCLC could guide future drug development, leading to more precise therapy and advances in treatment.

Investigating Novel Resistance Mechanisms to Third-Generation EGFR Tyrosine Kinase Inhibitor Osimertinib in Non–Small Cell Lung Cancer Patients

Abstract: Purpose: The third-generation EGFR tyrosine kinase inhibitor osimertinib is approved to treat patients with EGFR T790M-positive non-small cell lung cancer (NSCLC) who have developed resistance to earlier-generation drugs. Acquired EGFR C797S mutation has been reported to mediate osimertinib resistance in some patients. However, the remaining resistance mechanisms are largely unknown.Experimental Design: We performed mutation profiling using targeted next-generation sequencing (NGS) for 416 cancer-relevant genes on 93 osimertinib-resistant lung cancer patients' samples, mainly cell-free DNAs (cfDNAs), and matched pretreatment samples of 12 patients. In vitro experiments were conducted to functionally study the secondary EGFR mutations identified.Results:EGFR G796/C797, L792, and L718/G719 mutations were identified in 24.7%, 10.8%, and 9.7% of the cases, respectively, with certain mutations coexisting in one patient with different prevalence. L792 and L718 mutants markedly increased the half inhibitory concentration (IC50) of osimertinib in vitro, among which the L718Q mutation conferred the greatest resistance to osimertinib, as well as gefitinib resistance when not coexisting with T790M. Further analysis of the 12 matched pretreatment samples confirmed that these EGFR mutations were acquired during osimertinib treatment. Alterations in parallel or downstream oncogenes such as MET, KRAS, and PIK3CA were also discovered, potentially contributing to the osimertinib-resistance in patients without EGFR secondary mutations.Conclusions: We present comprehensive mutation profiles of a large cohort of osimertinib-resistance lung cancer patients using mainly cfDNA. Besides C797 mutations, novel secondary mutations of EGFR L718 and L792 residues confer osimertinib resistance, both in vitro and in vivo, and are of great clinical and pharmaceutical relevance. Clin Cancer Res; 24(13); 3097-107. ©2018 AACR.

CNS Efficacy of Osimertinib in Patients With T790M-Positive Advanced Non-Small-Cell Lung Cancer: Data From a Randomized Phase III Trial (AURA3).

Abstract: Purpose In patients with epidermal growth factor receptor ( EGFR) mutation-positive advanced non-small-cell lung cancer (NSCLC), there is an unmet need for EGFR-tyrosine kinase inhibitors with improved CNS penetration and activity against CNS metastases, either at initial diagnosis or time of progression. We report the first comparative evidence of osimertinib CNS efficacy versus platinum-pemetrexed from a phase III study (AURA3; ClinicalTrials.gov identifier: NCT02151981) in patients with EGFR T790M-positive advanced NSCLC who experience disease progression with prior EGFR-tyrosine kinase inhibitor treatment. Methods Patients with asymptomatic, stable CNS metastases were eligible for enrollment and were randomly assigned 2:1 to osimertinib 80 mg once daily or platinum-pemetrexed. A preplanned subgroup analysis was conducted in patients with measurable and/or nonmeasurable CNS lesions on baseline brain scan by blinded independent central neuroradiological review. The CNS evaluable for response set included only patients with one or more measurable CNS lesions. The primary objective for this analysis was CNS objective response rate (ORR). Results Of 419 patients randomly assigned to treatment, 116 had measurable and/or nonmeasurable CNS lesions, including 46 patients with measurable CNS lesions. At data cutoff (April 15, 2016), CNS ORR in patients with one or more measurable CNS lesions was 70% (21 of 30; 95% CI, 51% to 85%) with osimertinib and 31% (5 of 16; 95% CI, 11% to 59%) with platinum-pemetrexed (odds ratio, 5.13; 95% CI, 1.44 to 20.64; P = .015); the ORR was 40% (30 of 75; 95% CI, 29% to 52%) and 17% (7 of 41; 95% CI, 7% to 32%), respectively, in patients with measurable and/or nonmeasurable CNS lesions (odds ratio, 3.24; 95% CI, 1.33 to 8.81; P = .014). Median CNS duration of response in patients with measurable and/or nonmeasurable CNS lesions was 8.9 months (95% CI, 4.3 months to not calculable) for osimertinib and 5.7 months (95% CI, 4.4 to 5.7 months) for platinum-pemetrexed; median CNS progression-free survival was 11.7 months and 5.6 months, respectively (hazard ratio, 0.32; 95% CI, 0.15 to 0.69; P = .004). Conclusion Osimertinib demonstrated superior CNS efficacy versus platinum-pemetrexed in T790M-positive advanced NSCLC.

Landscape of Acquired Resistance to Osimertinib in EGFR-Mutant NSCLC and Clinical Validation of Combined EGFR and RET Inhibition with Osimertinib and BLU-667 for Acquired RET Fusion

Abstract: We present a cohort of 41 patients with osimertinib resistance biopsies, including two with an acquired CCDC6-RET fusion. While RET fusions have been identified in resistant EGFR-mutant NSCLC, their role in acquired resistance to EGFR inhibitors is not well described. To assess the biological implications of RET fusions in an EGFR-mutant cancer, we expressed CCDC6-RET in PC9 (EGFR del19) and MGH134 (EGFR L858R/T790M) cells and found that CCDC6-RET was sufficient to confer resistance to EGFR-TKIs. The selective RET inhibitors BLU-667 or cabozantinib resensitized CCDC6-RET-expressing cells to EGFR inhibition. Finally, we treated two patients with EGFR-mutant NSCLC and RET-mediated resistance with osimertinib and BLU-667. The combination was well-tolerated and led to rapid radiographic response in both patients. This study provides proof-of-concept that RET fusions can mediate acquired resistance to EGFR TKIs and that combined EGFR and RET inhibition with osimertinib/BLU-667 may be a well-tolerated and effective treatment strategy for such patients.

Landscape of EGFR-Dependent and -Independent Resistance Mechanisms to Osimertinib and Continuation Therapy Beyond Progression in EGFR-Mutant NSCLC.

Abstract: Purpose: Osimertinib was initially approved for T790M-positive non–small cell lung cancer (NSCLC) and, more recently, for first-line treatment of EGFR-mutant NSCLC. However, resistance mechanisms to osimertinib have been incompletely described. Experimental Design: Using cohorts from The University of Texas MD Anderson Lung Cancer Moonshot GEMINI and Moffitt Cancer Center lung cancer databases, we collected clinical data for patients treated with osimertinib. Molecular profiling analysis was performed at the time of progression in a subset of the patients. Results: In the 118 patients treated with osimertinib, 42 had molecular profiling at progression. T790M was preserved in 21 (50%) patients and lost in 21 (50%). EGFR C797 and L792 (26%) mutations were the most common resistance mechanism and were observed exclusively in T790M-preserved cases. MET amplification was the second most common alteration (14%). Recurrent alterations were observed in 22 genes/pathways, including PIK3CA, FGFR, and RET. Preclinical studies confirmed MET, PIK3CA, and epithelial-to-mesenchymal transition as potential resistance drivers. Alterations of cell-cycle genes were associated with shorter median progression-free survival (PFS, 4.4 vs. 8.8 months, P = 0.01). In 76 patients with progression, osimertinib was continued in 47 cases with a median second PFS (PFS2) of 12.6 months; 21 patients received local consolidation radiation with a median PFS of 15.5 months. Continuation of osimertinib beyond progression was associated with a longer overall survival compared with discontinuation (11.2 vs. 6.1 months, P = 0.02). Conclusions: Osimertinib resistance is associated with diverse, predominantly EGFR-independent genomic alterations. Continuation of osimertinib after progression, alone or in conjunction with radiotherapy, may provide prolonged clinical benefit in selected patients. See related commentary by Devarakonda and Govindan, p. 6112.

Third generation EGFR TKIs: current data and future directions.

Abstract: Acquired T790 M mutation is the commonest cause of resistance for advanced non-small cell lung cancer (NSCLC) epidermal growth factor receptor (EGFR) mutant patients who had progressed after first line EGFR TKI (tyrosine kinase inhibitor). Several third generation EGFR TKIs which are EGFR mutant selective and wild-type (WT) sparing were developed to treat these patients with T790 M acquired resistant mutation. Osimertinib is one of the third generation EGFR TKIs and is currently the most advanced in clinical development. Unfortunately, despite good initial response, patients who was treated with third generation EGFR TKI would develop acquired resistance and several mechanisms had been identified and the commonest being C797S mutation at exon 20. Several novel treatment options were being developed for patients who had progressed on third generation EGFR TKI but they are still in the early phase of development. Osimertinib under FLAURA study had been shown to have better progression-free survival over first generation EGFR TKI in the first line setting and likely will become the new standard of care.

Overcoming EGFR G724S -mediated osimertinib resistance through unique binding characteristics of second-generation EGFR inhibitors

Abstract: The emergence of acquired resistance against targeted drugs remains a major clinical challenge in lung adenocarcinoma patients. In a subgroup of these patients we identified an association between selection of EGFRT790M-negative but EGFRG724S-positive subclones and osimertinib resistance. We demonstrate that EGFRG724S limits the activity of third-generation EGFR inhibitors both in vitro and in vivo. Structural analyses and computational modeling indicate that EGFRG724S mutations may induce a conformation of the glycine-rich loop, which is incompatible with the binding of third-generation TKIs. Systematic inhibitor screening and in-depth kinetic profiling validate these findings and show that second-generation EGFR inhibitors retain kinase affinity and overcome EGFRG724S-mediated resistance. In the case of afatinib this profile translates into a robust reduction of colony formation and tumor growth of EGFRG724S-driven cells. Our data provide a mechanistic basis for the osimertinib-induced selection of EGFRG724S-mutant clones and a rationale to treat these patients with clinically approved second-generation EGFR inhibitors.

Sequential treatment with afatinib and osimertinib in patients with EGFR mutation-positive non-small-cell lung cancer: an observational study.

Abstract: Aim To assess outcomes in patients with EGFR mutation-positive (Del19, L858R) non-small-cell lung cancer receiving sequential afatinib and osimertinib in a real-world clinical setting. Materials & methods: In this retrospective, observational, multicenter study, patients (n = 204) had T790M-positive disease following first-line afatinib and started osimertinib treatment ≥10 months prior to data entry. Primary outcome was time on treatment. Results Overall median time on treatment was 27.6 months (90% CI: 25.9-31.3), 30.3 months (90% CI: 27.6-44.5) in Del19-positive patients and 46.7 months (90% CI: 26.8-not reached) in Asians. The 2-year overall survival was 78.9%. Conclusion In real-world clinical practice, sequential afatinib and osimertinib facilitates prolonged, chemotherapy-free treatment in patients with T790M acquired resistance, and is a potentially attractive strategy, especially for Del19-positive tumors. Trial registration number NCT03370770.

Optimizing outcomes in EGFR mutation-positive NSCLC: which tyrosine kinase inhibitor and when?

Abstract: Despite the efficacy of standard-of-care EGFR tyrosine kinase inhibitors (TKIs), erlotinib, gefitinib and afatinib, in EGFR mutation-positive non-small-cell lung cancer, resistance develops, most commonly due to the T790M mutation. Osimertinib showed clinical activity in the treatment of T790M-positive disease following progression on a first-line TKI, and is approved in this setting. Recently, osimertinib improved efficacy versus first-generation TKIs (erlotinib and gefitinib) in the first-line setting. Multiple factors can influence first-line treatment decisions, including subsequent therapy options, presence of brain metastases and tolerability, all of which should be considered in the long-term treatment plan. Further research into treatment sequencing is also needed, to optimize outcomes in EGFR mutation-positive non-small-cell lung cancer.

Cost-effectiveness of Osimertinib in the First-Line Treatment of Patients With EGFR-Mutated Advanced Non-Small Cell Lung Cancer.

Abstract: Importance The survival of patients with advanced non–small cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) gene mutations has improved substantially in the last decade with the development of targeted tyrosine kinase inhibitors (TKIs). Osimertinib, a third-generation TKI that is approved by the US Food and Drug Administration for the treatment of patients who developEGFRT790M mutations, has recently shown improved clinical outcomes compared with gefitinib and erlotinib for treatment-naive patients. Objective The aim of this study was to assess the cost-effectiveness of osimertinib for the first-line treatment of patients withEGFR-mutated NSCLC. Design, Setting, and Participants For this cost-effectiveness analysis, we extracted individual patient data from the FLAURA randomized clinical trial and used findings of our earlier meta-analysis to develop a decision-analytic model and determine the cost-effectiveness of osimertinib (AZD9291) compared with first- and second-generation EGFR-TKIs over a 10-year time horizon. All direct costs were based on US and Brazilian payer perspectives. Main Outcomes and Measures The main outcome of this study was the incremental cost-effectiveness ratio (ICER) expressed as cost per quality-adjusted life-year (QALY) gained by using osimertinib compared with first- or second-generation EGFR-TKIs in previously untreatedEGFR-mutated NSCLC. Results In the base case using the data as reported in the FLAURA trial, the incremental QALY for osimertinib was 0.594 compared with the first- and second-generation EGFR-TKIs. In the United States, the osimertinib ICERs were $226 527 vs erlotinib, $231 123 vs gefitinib, and $219 874 vs afatinib. In Brazil, the ICERs were $162 329, $180 804, and $175 432, respectively. The overall survival (95% CI) reported in the FLAURA trial (hazard ratio, 0.63; 95% CI, 0.45-0.88) had the strongest association with the ICER (ranging from $84 342 to $859 771). Osimertinib price adjustments to the FLAURA trial data improved cost-effectiveness. For example, a discount of 10% on osimertinib acquisition cost was associated with a 20% decreased ICER compared with the base case ICER, and a discount of 20% on osimertinib acquisition cost was associated with a 40% decreased ICER compared with the base case ICER. Conclusions and Relevance At current costs, by World Health Organization cost-effectiveness threshold criteria, osimertinib is not cost-effective for first-line therapy ofEGFR-mutated NSCLC in either the United States or Brazil.

Recent Progress of Small-Molecule Epidermal Growth Factor Receptor (EGFR) Inhibitors against C797S Resistance in Non-Small-Cell Lung Cancer

Abstract: The epidermal growth factor receptor (EGFR) has been a particular interest for drug development for treatment of non-small-cell lung cancer (NSCLC). The current third-generation EGFR small-molecule inhibitors, especially osimertinib, are at the forefront clinically for treatment of patients with NSCLC. However, a high percentage of these treated patients developed a tertiary cystein-797 to serine-790 (C797S) mutation in the EGFR kinase domain. This C797S mutation is thought to induce resistance to all current irreversible EGFR TKIs. In this Miniperspective, we present key mechanisms of resistance in response to third-generation EGFR TKIs, and emerging reports on novel EGFR TKIs to combat the resistance. Specifically, we analyze the allosteric and ATP-competitive inhibitors in terms of drug discovery, binding mechanism, and their potency and selectivity against EGFR harboring C797S mutations. Lastly, we provide some perspectives on new challenges and future directions in this field.

Antitumor Activity of Osimertinib, an Irreversible Mutant-Selective EGFR Tyrosine Kinase Inhibitor, in NSCLC Harboring EGFR Exon 20 Insertions.

Abstract: EGFR exon 20 insertions (Ex20Ins) account for 4% to 10% of EGFR activating mutations in non-small cell lung cancer (NSCLC). EGFR Ex20Ins tumors are generally unresponsive to first- and second-generation EGFR inhibitors, and current standard of care for NSCLC patients with EGFR Ex20Ins is conventional cytotoxic chemotherapy. Therefore, the development of an EGFR TKI that can more effectively target NSCLC with EGFR Ex20Ins mutations represents a major advance for this patient subset. Osimertinib is a third-generation EGFR TKI approved for the treatment of advanced NSCLC harboring EGFR T790M; however, the activity of osimertinib in EGFR Ex20Ins NSCLC has yet to be fully assessed. Using CRISPR-Cas 9 engineered cell lines carrying the most prevalent Ex20Ins mutations, namely Ex20Ins D770_N771InsSVD (22%) or Ex20Ins V769_D770InsASV (17%), and a series of patient-derived xenografts, we have characterized osimertinib and AZ5104 (a circulating metabolite of osimertinib) activities against NSCLC harboring Ex20Ins. We report that osimertinib and AZ5104 inhibit signaling pathways and cellular growth in Ex20Ins mutant cell lines in vitro and demonstrate sustained tumor growth inhibition of EGFR-mutant tumor xenograft harboring the most prevalent Ex20Ins in vivo The antitumor activity of osimertinib and AZ5104 in NSCLC harboring EGFR Ex20Ins is further described herein using a series of patient-derived xenograft models. Together these data support clinical testing of osimertinib in patients with EGFR Ex20Ins NSCLC. Mol Cancer Ther; 17(5); 885-96. ©2018 AACR.

Targeting HER2 Aberrations in Non-Small Cell Lung Cancer with Osimertinib.

Abstract: Purpose:HER2 (or ERBB2) aberrations, including both amplification and mutations, have been classified as oncogenic drivers that contribute to 2% to 6% of lung adenocarcinomas. HER2 amplification is also an important mechanism for acquired resistance to EGFR tyrosine kinase inhibitors (TKI). However, due to limited preclinical studies and clinical trials, currently there is still no available standard of care for lung cancer patients with HER2 aberrations. To fulfill the clinical need for targeting HER2 in patients with non-small cell lung cancer (NSCLC), we performed a comprehensive preclinical study to evaluate the efficacy of a third-generation TKI, osimertinib (AZD9291).Experimental Design: Three genetically modified mouse models (GEMM) mimicking individual HER2 alterations in NSCLC were generated, and osimertinib was tested for its efficacy against these HER2 aberrations in vivoResults: Osimertinib treatment showed robust efficacy in HER2wt overexpression and EGFR del19/HER2 models, but not in HER2 exon 20 insertion tumors. Interestingly, we further identified that combined treatment with osimertinib and the BET inhibitor JQ1 significantly increased the response rate in HER2-mutant NSCLC, whereas JQ1 single treatment did not show efficacy.Conclusions: Overall, our data indicated robust antitumor efficacy of osimertinib against multiple HER2 aberrations in lung cancer, either as a single agent or in combination with JQ1. Our study provides a strong rationale for future clinical trials using osimertinib either alone or in combination with epigenetic drugs to target aberrant HER2 in patients with NSCLC. Clin Cancer Res; 24(11); 2594-604. ©2018 AACRSee related commentary by Cappuzzo and Landi, p. 2470.

Management of Brain Metastases in Epidermal Growth Factor Receptor Mutant Non-Small-Cell Lung Cancer.

Abstract: Lung cancer remains a leading cause of mortality with 1.69 million deaths worldwide. Activating mutations in epidermal growth factor receptor (EGFR), predominantly exon 19 deletions and exon 21 L858R mutations, are known oncogenic drivers identified in 20-40% of non-small-cell lung cancers (NSCLC). 70% of EGFR-mutant NSCLC patients develop brain metastases (BM), compared to 38% in EGFR wild-type patients. First-generation tyrosine kinase inhibitors (TKIs), such as erlotinib and gefitinib have proven to be superior to chemotherapy in the front-line treatment of EGFR-mutant NSCLC, as has afatinib, a second-generation TKI. The most common acquired resistance mechanism is the development of a gatekeeper mutation in exon 20 T790M. Osimertinib has emerged as a third-generation EGFR TKI with proven activity in the front-line setting as well as in patients with a T790M acquired resistance mutation with remarkable CNS activity. As long-term survival outcomes in EGFR-mutant NSCLC continue to improve, the burden of BM becomes a greater challenge. Here, we review the literature related to the management of BM in EGFR-mutant NSCLC including the role of the three generations of EGFR TKIs, immunotherapy, and brain radiation.

Targeting EGFR in Lung Cancer: Current Standards and Developments.

Abstract: Lung cancer is the second most common malignant tumor and the leading cause of cancer death. Epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer (NSCLC) is a distinct subtype of lung cancer comprising approximately 15-40% of non-squamous tumors. The development of first- and second-generation EGFR tyrosine kinase inhibitors (TKIs) has been a significant step forward in the treatment of patients with EGFR-mutant tumors, and over the last few years has been the therapy of choice in the initial management of patients with activating mutations in EGFR, with some differences in efficacy and toxicity profile. Up to 50% of patients treated with first- and second-generation TKIs develop an EGFR exon 20 T790M mutation at the time of progression. In this context, osimertinib has shown a great benefit in terms of progression-free survival (PFS) in the second-line setting, including central nervous system metastasis control. The FLAURA trial, which compared osimertinib to first-generation inhibitors as first-line therapy, showed a clear PFS advantage for osimertinib and a trend towards an increased overall survival (OS) assessed by investigator review. Although T790M mutation is the most common mechanism of resistance to first- and second-generation EGFR TKIs, other EGFR-dependent and -independent mechanisms have been described, such as HER2 and MET amplifications or BRAF and MEK mutations. Some mechanisms of resistance to osimertinib and other third-generation TKIs have also been described. Several fourth-generation TKIs, targeted drug combinations and immunotherapy strategies are under investigation to overcome resistance to EGFR TKIs in order to improve EGFR-mutant NSCLC patient outcomes.

Standard-dose osimertinib for refractory leptomeningeal metastases in T790M-positive EGFR-mutant non-small cell lung cancer

Abstract: Standard-dose osimertinib for refractory leptomeningeal metastases in T790M-positive EGFR -mutant non-small cell lung cancer