Osimertinib Responses After Disease Progression in Patients Who Had Been Receiving Rociletinib

Clinical Trials for Oral, Inhaled and Intravenous Drug Delivery System for Lung Cancer and Emerging Nanomedicine-Based Approaches

Lung cancer is one of the most common malignant tumors worldwide and is characterized by high morbidity and mortality rates and a poor prognosis. It is the leading cause of cancer-related death in the United States and worldwide. Most patients with lung cancer are treated with chemotherapy, radiotherapy, or surgery; however, effective treatment options remain limited. In this review, we aim to provide an overview of clinical trials, ranging from Phase I to III, conducted on drug delivery systems for lung cancer treatment. The trials included oral, inhaled, and intravenous administration of therapeutics. Furthermore, the study also talks about the evolving paradigm of targeted therapy and immunotherapy providing promising directions for personalized treatment. In addition, we summarize the best results and limitations of these drug delivery systems and discuss the potential capacity of nanomedicine.

A mechanistic study of thiol addition to N-phenylacrylamide

Experimental data from a Brønsted-type plot, a solvent kinetic isotope effect, a pH-rate plot and temperature studies are all consistent with rate-limiting nucleophilic attack of thiolate followed by rapid protonation of the enolate adduct.

Mechanisms and management of 3rd‑generation EGFR‑TKI resistance in advanced non‑small cell lung cancer (Review)

Targeted therapy with epidermal growth factor receptor (EGFR)‑tyrosine kinase inhibitors (TKIs) is a standard modality of the 1st‑line treatments for patients with advanced EGFR‑mutated non‑small cell lung cancer (NSCLC), and substantially improves their prognosis. However, EGFR T790M mutation is the primary mechanism of 1st‑ and 2nd‑generation EGFR‑TKI resistance. Osimertinib is a representative of the 3rd‑generation EGFR‑TKIs that target T790M mutation, and has satisfactory efficacy in the treatment of T790M‑positive NSCLC with disease progression following use of 1st‑ or 2nd‑generation EGFR‑TKIs. Other 3rd‑generation EGFR‑TKIs, such as abivertinib, rociletinib, nazartinib, olmutinib and alflutinib, are also at various stages of development. However, the occurrence of acquired resistance is inevitable, and the mechanisms of 3rd‑generation EGFR‑TKI resistance are complex and incompletely understood. Genomic studies in tissue and liquid biopsies of resistant patients reveal multiple candidate pathways. The present review summarizes the recent findings in mechanisms of resistance to 3rd‑generation EGFR‑TKIs in advanced NSCLC, and provides possible strategies to overcome this resistance. The mechanisms of acquired resistance mainly include an altered EGFR signaling pathway (EGFR tertiary mutations and amplification), activation of aberrant bypassing pathways (hepatocyte growth factor receptor amplification, human epidermal growth factor receptor 2 amplification and aberrant insulin‑like growth factor 1 receptor activation), downstream pathway activation (RAS/RAF/MEK/ERK and PI3K/AKT/mTOR) and histological/phenotypic transformations (SCLC transformation and epithelial‑mesenchymal transition). The combination of targeted therapies is a promising strategy to treat osimertinib‑resistant patients, and multiple clinical studies on novel combined therapies are ongoing.

The Current State of Potential Therapeutic Modalities for Glioblastoma Multiforme: A Clinical Review

Glioblastoma multiforme (GBM), as the most lethal brain tumor, continues to be incurable. Considering the high mortality rate of GBM, it is crucial to develop new treatment approaches. Conventional therapies, including maximal surgical resection, radiation therapy, and chemotherapy (typically temozolomide), have not led to significant changes in the survival rates of GBM patients. However, emerging modalities, such as the use of tyrosine kinase inhibitors, mTOR inhibitors, NF-κB modulators, nitrosoureas, and immunotherapeutic agents have shown promising in improving GBM outcomes. In this context, we reviewed the current status of GBM treatment, the efficacy of existing standard therapies in improving disease outcomes, and future therapeutic directions.

Alterations in the Global Proteome and Phosphoproteome in Third Generation EGFR TKI Resistance Reveal Drug Targets to Circumvent Resistance

Lung cancer is the leading cause of cancer mortality worldwide. The treatment of patients with lung cancer harboring mutant EGFR with orally administered EGFR tyrosine kinase inhibitors (TKI) has been a paradigm shift. Osimertinib and rociletinib are third-generation irreversible EGFR TKIs targeting the EGFR T790M mutation. Osimertinib is the current standard of care for patients with EGFR mutations due to increased efficacy, lower side effects, and enhanced brain penetrance. Unfortunately, all patients develop resistance. Genomic approaches have primarily been used to interrogate resistance mechanisms. Here we characterized the proteome and phosphoproteome of a series of isogenic EGFR-mutant lung adenocarcinoma cell lines that are either sensitive or resistant to these drugs, comprising the most comprehensive proteomic dataset resource to date to investigate third generation EGFR TKI resistance in lung adenocarcinoma. Unbiased global quantitative mass spectrometry uncovered alterations in signaling pathways, revealed a proteomic signature of epithelial-mesenchymal transition, and identified kinases and phosphatases with altered expression and phosphorylation in TKI-resistant cells. Decreased tyrosine phosphorylation of key sites in the phosphatase SHP2 suggests its inhibition, resulting in subsequent inhibition of RAS/MAPK and activation of PI3K/AKT pathways. Anticorrelation analyses of this phosphoproteomic dataset with published drug-induced P100 phosphoproteomic datasets from the Library of Integrated Network-Based Cellular Signatures program predicted drugs with the potential to overcome EGFR TKI resistance. The PI3K/MTOR inhibitor dactolisib in combination with osimertinib overcame resistance both in vitro and in vivo. Taken together, this study reveals global proteomic alterations upon third generation EGFR TKI resistance and highlights potential novel approaches to overcome resistance. SIGNIFICANCE: Global quantitative proteomics reveals changes in the proteome and phosphoproteome in lung cancer cells resistant to third generation EGFR TKIs, identifying the PI3K/mTOR inhibitor dactolisib as a potential approach to overcome resistance.

Development of EGFR TKIs and Options to Manage Resistance of Third-Generation EGFR TKI Osimertinib: Conventional Ways and Immune Checkpoint Inhibitors

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR TKIs) have been first-line therapy in the treatment of non-small cell lung cancer (NSCLC) harboring EGFR sensitive mutations. Progression inevitably happens after 10–14 months of first- or second-generation EGFR TKIs treatment for acquired resistance. Owing to the successful identification of EGFR T790M, third-generation EGFR TKIs such as osimertinib were developed to target such resistance mutation. Nowadays, osimertinib has shown its efficacy both in first-line and second-line after resistance to previous generations of TKI treatment of EGFR-mutant NSCLC. However, drug resistance also emerges on third-generation EGFR TKIs. Multiple mechanisms of acquired resistance have been identified, and some novel strategies were reported to overcome third-generation TKI resistance. Immune checkpoint inhibitors (ICIs) have dramatically changed the prognosis of selected patients. For patients with EGFR-addicted metastatic NSCLC, ICIs have also revealed a potential role. In this review, we will take stock of mechanisms of acquired resistance to third-generation TKIs and discuss current challenges and future perspectives in clinical practice.

Recent updates on the resistance mechanisms to epidermal growth factor receptor tyrosine kinase inhibitors and resistance reversion strategies in lung cancer

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) have led to a substantial improvement in the prognosis of lung cancer patients by explicitly targeting the activating mutations within the EGFR. Initially, patients harboring tumors with EGFR mutations show progression-free survival and improvement in the response rates toward all-generation EGFR-TKIs; however, these agents fail to deliver the intended results in the long-term due to drug resistance. Therefore, it is necessary to recognize specific cardinal mechanisms that regulate the resistance phenomenon. Understanding the intricate mechanisms underlying EGFR-TKIs resistance in lung cancer could provide cognizance for more advanced targeted therapeutics. The present review features insights into current updates on the discrete mechanisms, including secondary or tertiary mutations, parallel and downstream signaling pathways, acquiring an epithelial-to-mesenchymal transition (EMT) signature, microRNAs (miRNAs), and epigenetic alterations, which lead to intrinsic and acquired resistance against EGFR-TKIs in lung cancer. In addition, this paper also reviews current possible strategies to overcome this issue using combination treatment of recently developed MET inhibitors, allosteric inhibitors or immunotherapies, transformation of EMT, targeting miRNAs, and epigenetic alterations in intrinsic and acquired EGFR-TKIs resistant lung cancer. In conclusion, multiple factors are responsible for intrinsic and acquired resistance to EGFR-TKIs and understanding of the detailed molecular mechanisms, and recent advancements in pharmacological studies are needed to develop new strategies to overcome intrinsic and acquired EGFR-TKIs resistance in lung cancer.

Frontiers of ctDNA, targeted therapies, and immunotherapy in non-small-cell lung cancer

Non-small-cell lung cancer (NSCLC), a main subtype of lung cancer, is one of the most common causes of cancer death in men and women worldwide. Circulating tumor DNA (ctDNA), tyrosine kinase inhibitors (TKIs) and immunotherapy have revolutionized both our understanding of NSCLC, from its diagnosis to targeted NSCLC therapies, and its treatment. ctDNA quantification confers convenience and precision to clinical decision making. Furthermore, the implementation of TKI-based targeted therapy and immunotherapy has significantly improved NSCLC patient quality of life. This review provides an update on the methods of ctDNA detection and its impact on therapeutic strategies; therapies that target epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase (ALK) using TKIs such as osimertinib and lorlatinib; the rise of various resistant mechanisms; and the control of programmed cell death-1 (PD-1), programmed cell death ligand-1 (PD-L1), and cytotoxic T-lymphocyte antigen-4 (CTLA-4) by immune checkpoint inhibitors (ICIs) in immunotherapy; blood tumor mutational burden (bTMB) calculated by ctDNA assay as a novel biomarker for immunotherapy. However, NSCLC patients still face many challenges. Further studies and trials are needed to develop more effective drugs or therapies to treat NSCLC.

Clinical management of third-generation EGFR inhibitor-resistant patients with advanced non-small cell lung cancer: Current status and future perspectives

Discovery of activating mutations in epidermal growth factor receptor (EGFR) as a predictive biomarker for first-generation EGFR tyrosine kinase inhibitors (TKIs) has initiated an era of precision oncology for the treatment of advanced EGFR-mutant non-small cell lung cancer (NSCLC). Despite the robust efficacy of first- and second-generation EGFR TKIs, disease relapse is inevitable. EGFR T790M mutation is the predominant cause of disease relapse and third-generation, irreversible EGFR inhibitors designed for targeting EGFR T790M and activating mutations have demonstrated promising clinical activity and tolerability. Unfortunately, disease progression inevitably occurs and heterogenous resistance mechanisms have been reported with limited subsequent treatment strategies available. Till now, treatment approaches for patients progressed from third-generation EGFR TKIs have not been clearly established. In this review, we summarize the recent findings in resistance mechanisms to third-generation EGFR TKIs and emerging treatment approaches for EGFR-mutant patients after resistance to third-generation EGFR TKIs. We further discuss clinical challenges and future perspectives for management of EGFR-mutant patients resistant to third-generation EGFR TKIs.

Phase I study of TAS-121, a third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, in patients with non-small-cell lung cancer harboring EGFR mutations

Purpose We investigated the safety, tolerability, pharmacokinetics, and efficacy of TAS-121, a novel, potent, and highly selective third-generation epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) in Japanese patients with advanced EGFR mutation-positive non-small-cell lung cancer (NSCLC) previously treated with EGFR-TKI. Methods This was an open-label, non-randomized, multi-center, dose escalation, phase I study conducted in three phases (dose escalation, expansion, and extension phases). TAS-121 was administered orally once daily (QD) or twice daily (BID) under fasting conditions in a 21-day treatment cycle. The primary endpoint was dose-limiting toxicities (DLTs) during Cycle 1 of the dose escalation phase. Results In total, 134 patients received treatment. Five and three patients presented a DLT with the QD and BID regimens, respectively. The DLTs were drug-induced liver injury, platelet count decreased, urticaria, interstitial lung disease, and left ventricular failure. The maximum tolerated dose (MTD) was 10 mg/day QD and 8 mg/day BID in the dose escalation phase. The most common adverse drug reactions (ADRs) were dermatological toxicity (89.6%), platelet count decreased (67.2%), and pyrexia (44%) among all patients. Rate of discontinuations due to ADRs at the MTD level were 11.1% with TAS-121 10 mg/day QD and 7.9% with TAS-121 8 mg/day BID. Among 86 T790M-positive patients (confirmed by blood serum sampling in most patients), the objective response rate (ORR) was 28% and highest at 8 mg/day BID (39%). Among 16 T790M-negative patients, the ORR was 19%. Conclusions TAS-121 was well tolerated up to the MTD and demonstrated antitumor activity in Japanese T790M-positive NSCLC patients. Clinical trial registration: JapicCTI-142651.

[Mechanisms of Resistance to the Third-generation Epidermal Growth Factor Receptor-Tyrosine Kinase Inhibitors in Non-small Cell Lung Cancer]

表皮生长因子受体酪氨酸激酶抑制剂（epidermal growth factor receptor-tyrosine kinase inhibitors, EGFRTKIs）靶向治疗已成为EGFR基因突变晚期非小细胞肺癌（non-small cell lung cancer, NSCLC）患者的一线治疗方法。第三代EGFR-TKIs用于一、二代TKIs耐药EGFR T790M突变NSCLC的治疗，给晚期肺癌患者带来更多的生存获益。然而，第三代EGFR-TKIs应用一段时间后不可避免地会出现耐药。肿瘤的异质性决定了耐药机制的多样性，第三代EGFR-TKIs的耐药包括依赖EGFR通路（新发突变、T790M减少或消失和EGFR基因扩增等）和不依赖EGFR通路（旁路途径的激活和细胞表型的转变）两大类，现就此问题进行简单的综述。

Preclinical studies reveal that LSD1 inhibition results in tumor growth arrest in lung adenocarcinoma independently of driver mutations

Lung adenocarcinoma (LUAD) is the most prevalent subtype of non-small cell lung cancer. Despite the development of novel targeted and immune therapies, the 5-year survival rate is still only 21%, indicating the need for more efficient treatment regimens. Lysine-specific demethylase 1 (LSD1) is an epigenetic eraser that modifies histone 3 methylation status, and is highly overexpressed in LUAD. Using representative human cell culture systems and two autochthonous transgenic mouse models, we investigated inhibition of LSD1 as a novel therapeutic option for treating LUAD. The reversible LSD1 inhibitor HCI-2509 significantly reduced cell growth with an IC₅₀ of 0.3-5 μmin vitro, which was linked to an enhancement of histone 3 lysine methylation. Most importantly, growth arrest, as well as inhibition of the invasion capacities, was independent of the underlying driver mutations. Subsequent expression profiling revealed that the cell cycle and replication machinery were prominently affected after LSD1 inhibition. In addition, our data provide evidence that LSD1 blockade significantly interferes with EGFR downstream signaling. Finally, our in vitro results were confirmed by preclinical therapeutic approaches, including the use of two autochthonous transgenic LUAD mouse models driven by either EGFR or KRAS mutations. Importantly, LSD1 inhibition resulted in significantly lower tumor formation and a strong reduction in tumor progression, which were independent of the underlying mutational background of the mouse models. Hence, our findings provide substantial evidence indicating that tumor growth of LUAD can be markedly decreased by HCI-2509 treatment, suggesting its use as a single agent maintenance therapy or combined therapeutical application in novel concerted drug approaches.

Increased Synthesis of MCL-1 Protein Underlies Initial Survival of EGFR-Mutant Lung Cancer to EGFR Inhibitors and Provides a Novel Drug Target

Purpose: EGFR inhibitors (EGFRi) are effective against EGFR-mutant lung cancers. The efficacy of these drugs, however, is mitigated by the outgrowth of resistant cells, most often driven by a secondary acquired mutation in EGFR, T790M We recently demonstrated that T790M can arise de novo during treatment; it follows that one potential therapeutic strategy to thwart resistance would be identifying and eliminating these cells [referred to as drug-tolerant cells (DTC)] prior to acquiring secondary mutations like T790M Experimental Design: We have developed DTCs to EGFRi in EGFR-mutant lung cancer cell lines. Subsequent analyses of DTCs included RNA-seq, high-content microscopy, and protein translational assays. Based on these results, we tested the ability of MCL-1 BH3 mimetics to combine with EGFR inhibitors to eliminate DTCs and shrink EGFR-mutant lung cancer tumors in vivo Results: We demonstrate surviving EGFR-mutant lung cancer cells upregulate the antiapoptotic protein MCL-1 in response to short-term EGFRi treatment. Mechanistically, DTCs undergo a protein biosynthesis enrichment resulting in increased mTORC1-mediated mRNA translation of MCL-1, revealing a novel mechanism in which lung cancer cells adapt to short-term pressures of apoptosis-inducing kinase inhibitors. Moreover, MCL-1 is a key molecule governing the emergence of early EGFR-mutant DTCs to EGFRi, and we demonstrate it can be effectively cotargeted with clinically emerging MCL-1 inhibitors both in vitro and in vivo Conclusions: Altogether, these data reveal that this novel therapeutic combination may delay the acquisition of secondary mutations, therefore prolonging therapy efficacy. Clin Cancer Res; 24(22); 5658-72. ©2018 AACR.

Protein Tyrosine Signaling and its Potential Therapeutic Implications in Carcinogenesis

Protein tyrosine phosphorylation is a crucial signaling mechanism that plays a role in epithelial carcinogenesis. Protein tyrosine kinases (PTKs) control various cellular processes including growth, differentiation, metabolism, and motility by activating major signaling pathways including STAT3, AKT, and MAPK. Genetic mutation of PTKs and/or prolonged activation of PTKs and their downstream pathways can lead to the development of epithelial cancer. Therefore, PTKs became an attractive target for cancer prevention. PTK inhibitors are continuously being developed, and they are currently used for the treatment of cancers that show a high expression of PTKs. Protein tyrosine phosphatases (PTPs), the homeostatic counterpart of PTKs, negatively regulate the rate and duration of phosphotyrosine signaling. PTPs initially were considered to be only housekeeping enzymes with low specificity. However, recent studies have demonstrated that PTPs can function as either tumor suppressors or tumor promoters, depending on their target substrates. Together, both PTK and PTP signal transduction pathways are potential therapeutic targets for cancer prevention and treatment.

Osimertinib for Previously Treated Patients With Advanced EGFR T790M Mutation-Positive NSCLC: Tolerability and Diagnostic Methods From an Expanded Access Program

Introduction

The osimertinib (AZD9291) US Expanded Access Program (EAP) provided compassionate access to osimertinib prior to US Food and Drug Administration (FDA) approval for patients with advanced/metastatic epidermal growth factor receptor (EGFR) T790M-positive non-small cell lung cancer (NSCLC) following progression on tyrosine kinase inhibitors (TKIs) targeting EGFR. Here, we report the patient demographics, safety and tolerability, and diagnostic methods used for T790M testing in the EAP.

Methods

Adult patients with EGFR T790M-positive NSCLC following progression on prior EGFR-TKI therapy (irrespective of line of therapy) were enrolled in the EAP and treated with 80 mg osimertinib once daily until dose reduction, discontinuation, or completion of the EAP following FDA approval (November 2015). Various testing methods were allowed for the required T790M testing.

Results

In total, 248 patients from 25 centers throughout the USA were enrolled in the EAP. The starting dose of 80 mg osimertinib once daily was maintained for 96% (n = 238) of patients over the duration of the EAP (median duration of exposure 84 days). Most patients (overall 83% [n = 205/238]; patients aged ≥ 75 years 83% [n = 48/58]) completed the EAP and transitioned to commercially available osimertinib following FDA approval. Serious adverse events considered to be treatment related by investigators were reported in five patients (2%), all aged ≥ 65 years, and were dyspnea, deep vein thrombosis, femur fracture, alanine aminotransferase increase, and pneumonitis, respectively. A variety of biospecimen types were collected: solid tumor tissue (73%), blood (20%), cytology (6%), and urine (2%). PCR-based methods were most commonly used for determining EGFR mutation status (47%) followed by next-generation sequencing (33%).

Conclusion

In a real-world setting, osimertinib was well tolerated, and most patients, including patients aged ≥ 75 years, transitioned to commercially available osimertinib following FDA approval. The EAP suggests there has been an uptake of minimally invasive T790M testing methods at some centers.

Funding

AstraZeneca (Wilmington, DE, USA).

Role of Epidermal Growth Factor Receptor (EGFR) Inhibitors and Radiation in the Management of Brain Metastases from EGFR Mutant Lung Cancers

The growth of genotype-directed targeted therapies, such as inhibitors of the epidermal growth factor receptor (EGFR), has revolutionized treatment for some patients with oncogene-addicted lung cancer. However, as systemic control for these patients has improved, brain metastases remain an important source of morbidity and mortality. Traditional treatment for brain metastases has been radiotherapy, either whole-brain radiation or stereotactic radiosurgery. The growing availability of drugs that can cross the blood-brain barrier and have activity in the central nervous system (CNS) has led to many studies investigating whether targeted therapy can be used in combination with or in lieu of radiation. In this review, we summarize the key literature about the incidence and nature of EGFR-mutant brain metastases (EGFR BMs), the data about the activity of EGFR inhibitors in the CNS, and whether they can be used as front-line therapy for brain metastases. Although initial use of tyrosine kinase inhibitors for EGFR BMs can often be an effective treatment strategy, multidisciplinary evaluation is critical, and prospective studies are needed to clarify which patients may benefit from early radiotherapy.

IMPLICATIONS FOR PRACTICE

Management of brain metastases in epidermal growth factor receptor (EGFR) mutant lung cancer is a common clinical problem. The question of whether to start initial therapy with an EGFR inhibitor or radiotherapy (either whole-brain radiotherapy or stereotactic radiosurgery) is controversial. The development of novel EGFR inhibitors with enhanced central nervous system (CNS) penetration is an important advance in the treatment of CNS disease. Multidisciplinary evaluation and evaluation of extracranial disease status are critical to choosing the best treatment option for each patient.

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

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.

MET or NRAS amplification is an acquired resistance mechanism to the third-generation EGFR inhibitor naquotinib

As a third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI), osimeritnib is the standard treatment for patients with non-small cell lung cancer harboring the EGFR T790M mutation; however, acquired resistance inevitably develops. Therefore, a next-generation treatment strategy is warranted in the osimertinib era. We investigated the mechanism of resistance to a novel EGFR-TKI, naquotinib, with the goal of developing a novel treatment strategy. We established multiple naquotinib-resistant cell lines or osimertinib-resistant cells, two of which were derived from EGFR-TKI-naïve cells; the others were derived from gefitinib- or afatinib-resistant cells harboring EGFR T790M. We comprehensively analyzed the RNA kinome sequence, but no universal gene alterations were detected in naquotinib-resistant cells. Neuroblastoma RAS viral oncogene homolog (NRAS) amplification was detected in naquotinib-resistant cells derived from gefitinib-resistant cells. The combination therapy of MEK inhibitors and naquotinib exhibited a highly beneficial effect in resistant cells with NRAS amplification, but the combination of MEK inhibitors and osimertinib had limited effects on naquotinib-resistant cells. Moreover, the combination of MEK inhibitors and naquotinib inhibited the growth of osimertinib-resistant cells, while the combination of MEK inhibitors and osimertinib had little effect on osimertinib-resistant cells. Clinical assessment of this novel combination (MEK inhibitors and naquotinib) is worth considering in osimertinib-resistant lung tumors.

Etirinotecan Pegol (NKTR-102) in Third-line Treatment of Patients With Metastatic or Recurrent Non-Small-cell Lung Cancer: Results of a Phase II Study

BACKGROUND

Third-line treatment options are limited for patients with metastatic non-small-cell lung cancer (NSCLC). Etirinotecan pegol (NKTR-102) is a long-acting topoisomerase-I inhibitor. We conducted a single-arm phase II trial to evaluate its efficacy in third-line treatment.

PATIENTS AND METHODS

Patients aged ≥ 18 years with histologically proven NSCLC who had received 2 previous systemic therapy regimens, measurable disease, Eastern Cooperative Oncology Group (ECOG) performance status ≤ 1, and adequate end-organ function were eligible. Etirinotecan pegol was administered at a dose of 145 mg/m² intravenously once every 3 weeks until progression. The response was assessed every 6 weeks using Response Evaluation Criteria In Solid Tumors, version 1.1. The primary endpoint was the overall objective response rate. The secondary endpoints included progression-free survival (PFS), overall survival (OS) and safety. A Simon 2-stage design was implemented for futility.

RESULTS

From January 2013 to January 2015, 40 patients were enrolled. Their median age was 66 years (range, 19-85 years), 45% were female, 30% had an ECOG performance status of 0, 96% were current and former smokers, and 31 had adenocarcinoma. Patients received a median of 3 cycles (range, 2-15) of protocol therapy. The best response was a partial response in 2 patients. The treatment was well tolerated; 3 patients had grade 3 gastrointestinal toxicity attributable to therapy. The median PFS was 2.3 months (95% confidence interval [CI], 1.3-4.4 months), and the median OS was 7.1 months (95% CI 4.2-11.4 months).

CONCLUSIONS

Etirinotecan pegol was well tolerated and led to 2 partial responses and disease stabilization with this third-line treatment of metastatic NSCLC. However, the study failed to meet its prespecified response rate endpoint.

A Phase I, Dose Escalation Study of Oral ASP8273 in Patients with Non-small Cell Lung Cancers with Epidermal Growth Factor Receptor Mutations

Purpose: Acquired EGFR T790M mutations are the most frequently identified resistance mechanism to EGFR tyrosine kinase inhibitors (TKI) in patients with EGFR-mutant lung cancers. ASP8273 is a third-generation EGFR TKI with antitumor activity in preclinical models of EGFR-mutant lung cancer that targets mutant EGFR, including EGFR T790M.Experimental Design: In this multicohort, phase I study (NCT02113813), escalating doses of ASP8273 (25-500 mg) were administered once daily to non-small cell lung cancer (NSCLC) patients with disease progression after prior treatment with an EGFR TKI. EGFR T790M was required for all cohorts, except the dose escalation cohort. Primary endpoints were safety/tolerability; secondary endpoints were determination of the RP2D, pharmacokinetic profile, and preliminary antitumor activity of ASP8273. Evaluation of the use of EGFR mutations in circulating free DNA (cfDNA) as a biomarker of ASP8273 treatment effects was an exploratory endpoint.Results: A total of 110 patients were treated with ASP8273 across dose escalation (n = 36), response-expansion (n = 36), RP2D (300 mg; n = 19) and food-effect (n = 19) cohorts. The most common treatment-emergent adverse events included diarrhea, nausea, fatigue, constipation, vomiting, and hyponatremia. Across all doses, in patients with EGFR T790M, the response rate was 30.7% (n = 27/88; 95% CI, 19.5%-44.5%), and median progression-free survival was 6.8 months (95% CI, 5.5-10.1 months). EGFR mutations in cfDNA, both the activating mutation and EGFR T790M, became undetectable in most patients in the setting of clinical response and reemerged upon disease progression.Conclusions: ASP8273 was well tolerated and promoted antitumor activity in patients with EGFR-mutant lung cancer with disease progression on prior EGFR TKI therapy. Clin Cancer Res; 23(24); 7467-73. ©2017 AACR.

Systemic Treatment of Brain Metastases

Lung cancer continues to be the leading cause of cancer-related mortality in the United States. Brain metastases are a significant problem in patients with lung cancer and have conventionally been treated with whole-brain radiation. This article reviews the data for systemic chemotherapy to treat brain metastasis from lung cancer and examines the activity of small molecule tyrosine kinase inhibitors for the targeted therapy for brain metastases from EGFR-mutant and ALK-rearranged non-small cell lung cancer. Future directions for evaluating the role of immunotherapy in treating brain metastasis are also discussed.

A novel EGFR-TKI inhibitor (cAMP-H3BO3complex) combined with thermal therapy is a promising strategy to improve lung cancer treatment outcomes

Purpose

Although EGFR-TKIs (epidermal growth factor receptor tyrosine kinase inhibitors) induce favorable responses as first-line non-small cell lung cancer treatments, drug resistance remains a serious problem. Meanwhile, thermal therapy also shows promise as a cancer therapy strategy. Here we combine a novel EGFR-TKI treatment with thermal therapy to improve lung cancer treatment outcomes.

Results

The results suggest that the cAMP-H₃BO₃ complex effectively inhibits EGFR auto-phosphorylation, while inducing apoptosis and cell cycle arrest in vitro. Compared to the negative control, tumor growth was significantly suppressed in mice treated with oxidative phosphorylation uncoupler thyroxine sodium and either cAMP-H₃BO₃ complex or cAMP-H₃BO₃ complex (P < 0.05). Moreover, the body temperature increase induced by treatment with thyroxine sodium inhibited tumor growth. Immunohistochemical analyses showed that A549 cell apoptosis was significantly higher in the cAMP-H₃BO₃ complex plus thyroxine sodium treatment group than in the other groups. Moreover,Ca²⁺ content analysis showed that the Ca²⁺ content of tumor tissue was significantly higher in the cAMP-H₃BO₃ complex plus thyroxine sodium treatment group than in other groups.

Materials and Methods

Inhibition of EGFR auto-phosphorylation by cAMP and cAMP-H₃BO₃ complex was studied using autoradiography and western blot. The antitumor activity of the novel EGFR inhibitor (cAMP-H₃BO₃ complex) with or without an oxidative phosphorylation uncoupler (thyroxine sodium) was investigated in vitro and in a nude mouse xenograft lung cancer model incorporating human A549 cells.

Conclusions

cAMP-H₃BO₃ complex is a novel EGFR-TKI. Combination therapy using cAMP-H₃BO₃ with thyroxine sodium-induced thermal therapy may improve lung cancer treatment outcomes.

Epidermal growth factor receptor T790M mutation-positive metastatic non-small-cell lung cancer: focus on osimertinib (AZD9291)

Adenocarcinoma is the most common type of non-small-cell lung cancer (NSCLC). Adenocarcinoma with epidermal growth factor receptor (EGFR) mutations accounts for 8%–30% of all cases of NSCLC depending on the geography and ethnicity. EGFR-mutated NSCLC usually responds to first-line therapy with EGFR tyrosine kinase inhibitors (TKIs). However, there is eventual loss of efficacy to TKIs due to development of resistance. The most frequent cause for resistance is a second EGFR mutation in exon 20 (T790M), which is encountered in up to 62% of patients. Osimertinib is one of the third-generation EGFR TKIs with a high selective potency against T790M mutants. In Phase I trial of osimertinib in advanced lung cancer after progression on EGFR TKIs, the response rate and disease control rate were 61% and 95%, respectively. A subsequent Phase II (AURA2) trial demonstrated a disease control rate of 92%, a response rate of 71%, a median duration of response of 7.8 months, and a median progression-free survival of 8.6 months. Osimertinib was approved by the US Food & Drug Administration in November 2015 for patients whose tumors exhibited T790M mutation and for those with progressive disease on other EGFR TKIs. In this review, we address the role of EGFR TKIs in the management of EGFR mutation lung cancer and the mechanisms of resistance to TKIs with a focus on the role of osimertinib. Data from completed trials of osimertinib, ongoing trials, as well as novel diagnostic methods to detect EGFR T790M mutation are reviewed.

Sequencing brain metastases and opportunities for targeted therapies

CNS metastases have long been recognized as a common and late complication of systemic malignancies. They represent the most common tumor of the brain. As outcomes and overall survival improve with better tolerated and more durable responses from therapies for systemic cancers, the incidence and prevalence of brain metastases is likely to increase. Among the most common systemic cancers leading to brain metastases include lung, melanoma, breast (triple-negative histology) and renal cell cancers. To date, there has been infrequent involvement of gastrointestinal and gynecologic malignancies; however, this may also change, reflecting improvement in overall survival and therapeutic regimens. Traditional therapy of brain metastases has focused on surgery, radiation therapy or best supportive/palliative care. The advent of modern genomic techniques, including next-generation and whole-exome sequencing, has allowed for the identification of unique markers and potential drivers of metastatic pathways. This review aims to discuss and highlight the known drivers of disease and the opportunities for ultimate development of targeted therapies.

Treatment in EGFR-mutated Non-small Cell Lung Cancer: How to Block the Receptor and overcome Resistance Mechanisms

In non-small cell lung cancer (NSCLC), the identification of epidermal growth factor receptor (EGFR) mutations and the parallel development of EGFR tyrosine kinase inhibitors (TKIs) have radically changed the therapeutic management strategies. Currently, erlotinib, gefitinib, and afatinib are all approved as standard first-line treatment in EGFR-mutated NSCLC. However, despite the proven efficacy, some EGFR-mutated NSCLCs do not respond to EGFR TKIs, while some patients, after a favorable and prolonged response to EGFR TKIs, inevitably progress within about 10-14 months. Epidermal growth factor receptor-dependent mechanisms, activation of alternative pathways, or phenotypic transformation can cause the resistance to EGFR TKIs. The exon 20 p.Thr790Met point mutation (T790M) is responsible for about 60% of cases of resistance when progression occurs. A third-generation TKI, osimertinib, improved outcome in patients harboring T790M after first- and second-generation TKI treatment. However, resistance develops even after treatment with third-generation drugs. To date, the Cys797Ser (C797S) mutation in exon 20 of EGFR is the most well-known resistance mutation after osimertinib. Fourth-generation TKIs are already under development. Nevertheless, additional information is needed to better understand and effectively overcome resistance. The aim of this review is to report recent advances and future perspectives in the treatment of EGFR-mutated NSCLC, highlighting the resistance mechanisms that underlie disease progression.

Mechanisms of Resistance to Target Therapies in Non-small Cell Lung Cancer

Targeted therapies are revolutionizing the treatment of advanced non-small cell lung cancer (NSCLC). The discovery of key oncogenic events mainly in lung adenocarcinoma, like EGFR mutations or ALK rearrangements, has changed the treatment landscape while improving the prognosis of lung cancer patients. Inevitably, virtually all patients initially treated with targeted therapies develop resistance because of the emergence of an insensitive cellular population, selected by pharmacologic pressure. Diverse mechanisms of resistance, in particular to EGFR, ALK and ROS1 tyrosine-kinase inhibitors (TKIs), have now been discovered and may be classified in three different groups: (1) alterations in the target (such as EGFR T790M and ALK or ROS1 mutations); (2) activation of alternative pathways (i.e. MET amplification, KRAS mutations); (3) phenotype transformation (to small cell lung cancer, epithelial-mesenchymal transition). These basic mechanisms are informing the development of novel therapeutic strategies to overcome resistance in the clinic. Novel-generation molecules include osimertinib, for EGFR-T790M-positive patients, and new ALK-TKIs. Nevertheless, the possible concomitant presence of multiple resistance mechanisms, as well as their heterogeneity among cells and disease localizations, makes research in this field particularly arduous. In this chapter, available evidence and perspectives concerning precise mechanisms of escape to pharmacological inhibition in oncogene-addicted NSCLC are reported for single targets, including but not limited to EGFR and ALK.

Update on recent preclinical and clinical studies of T790M mutant-specific irreversible epidermal growth factor receptor tyrosine kinase inhibitors

The first- and second-generation epidermal growth factor receptor tyrosine kinase inhibitors (1/2G EGFR-TKIs) gefitinib, erlotinib, and afatinib have all been approved as standard first-line treatments for advanced EGFR mutation-positive non-small cell lung cancer. The third-generation (3G) EGFR-TKIs have been developed to overcome the EGFR T790M mutation, which is the most common mechanism of acquired resistance to 1/2G EGFR-TKI treatment. This resistance mutation develops in half of the patients who respond to 1/2G EGFR-TKI therapy. The structures of the novel 3G EGFR-TKIs are different from those of 1/2G EGFR-TKIs. Particularly, 3G EGFR-TKIs have lower affinity to wild-type EGFR, and are therefore associated with lower rates of skin and gastrointestinal toxicities. However, many of the adverse events (AEs) that are observed in patients receiving 3G EGFR-TKIs have not been observed in patients receiving 1/2G EGFR-TKIs. Although preclinical studies have revealed many possible mechanisms for these AEs, the causes of some AEs remain unknown. Many mechanisms of resistance to 3G EGFR-TKI therapy have also been reported. Here, we have reviewed the recent clinical and preclinical developments related to novel 3G EGFR-TKIs, including osimertinib, rociletinib, olmutinib, EGF816, and ASP8273.

Third-generation epidermal growth factor receptor-tyrosine kinase inhibitors in T790M-positive non-small cell lung cancer: review on emerged mechanisms of resistance

Osimertinib, third-generation epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI), has been approved in the US and EU for the treatment of EGFR mutant T790M-positive non-small cell lung cancer (NSCLC) patients resistant to first- or second-generation EGFR-TKIs, such as gefitinib, erlotinib and afatinib. Although exciting survival data and response rates have been registered in patients treated with this and other third-generation EGFR-TKIs, unfortunately acquired resistance still occurs after approximately 10 months. Mechanisms determining progression of disease are heterogeneous and not fully understood. EGFR-dependent resistance mechanisms (such as new EGFR mutations), bypass pathway activation [as erb-b2 receptor tyrosine kinase 2 (HER2) or MET amplification] and histological transformation [in small cell lung cancer (SCLC)] have been reported, similarly to previous generation TKIs. Here, we review principle mechanisms of innate and acquired resistance described in literature both in clinical and preclinical settings during NSCLC treatment with third-generation EGFR-TKIs.

Clinical Application of Picodroplet Digital PCR Technology for Rapid Detection of EGFR T790M in Next-Generation Sequencing Libraries and DNA from Limited Tumor Samples

Although next-generation sequencing (NGS) is a robust technology for comprehensive assessment of EGFR-mutant lung adenocarcinomas with acquired resistance to tyrosine kinase inhibitors, it may not provide sufficiently rapid and sensitive detection of the EGFR T790M mutation, the most clinically relevant resistance biomarker. Here, we describe a digital PCR (dPCR) assay for rapid T790M detection on aliquots of NGS libraries prepared for comprehensive profiling, fully maximizing broad genomic analysis on limited samples. Tumor DNAs from patients with EGFR-mutant lung adenocarcinomas and acquired resistance to epidermal growth factor receptor inhibitors were prepared for Memorial Sloan-Kettering-Integrated Mutation Profiling of Actionable Cancer Targets sequencing, a hybrid capture-based assay interrogating 410 cancer-related genes. Precapture library aliquots were used for rapid EGFR T790M testing by dPCR, and results were compared with NGS and locked nucleic acid-PCR Sanger sequencing (reference high sensitivity method). Seventy resistance samples showed 99% concordance with the reference high sensitivity method in accuracy studies. Input as low as 2.5 ng provided a sensitivity of 1% and improved further with increasing DNA input. dPCR on libraries required less DNA and showed better performance than direct genomic DNA. dPCR on NGS libraries is a robust and rapid approach to EGFR T790M testing, allowing most economical utilization of limited material for comprehensive assessment. The same assay can also be performed directly on any limited DNA source and cell-free DNA.

Treatment of brain metastases in the modern genomic era

Development of brain metastasis (BM) portends a dismal prognosis for patients with cancer. Melanomas and carcinomas of the lung, breast, and kidney are the most common malignancies to metastasize to the brain. Recent advances in molecular genetics have enabled the identification of actionable, clinically relevant genetic alterations within primary tumors and their corresponding metastases. Adoption of genotype-guided treatment strategies for the management of systemic malignancy has resulted in dramatic and durable responses. Unfortunately, despite these therapeutic advances, central nervous system (CNS) relapses are not uncommon. Although these relapses have historically been attributed to limited blood brain barrier penetration of anti-neoplastic agents, recent work has demonstrated genetic heterogeneity such that metastatic sites, including BM, harbor relevant genetic alterations that are not present in primary tumor biopsies. This improved insight into molecular mechanisms underlying site specific recurrences can inform strategies for targeting these oncogenic drivers. Thus, development of rational, genomically guided CNS-penetrant therapies is crucial for ongoing therapeutic success.

New developments in the management of non-small-cell lung cancer, focus on rociletinib: what went wrong?

Recently, the development of the third-generation epidermal growth factor receptor-small molecule inhibitor (EGFR-TKI) rociletinib had failed. In this review, the wide-ranging aspects of the evolution of EGFR-TKIs were collected, with a special focus on rociletinib. The influence of different oncogenic mutations on EGFR activity was also discussed. Resistance to the first (erlotinib, gefitinib)- and second (afatinib)-generation EGFR-TKIs provided the rationale behind the development of the third-generation inhibitors (rociletinib, osimertinib). On the basis of these data, a comparison of their efficacy on the different mutated EGFRs and the respective resistance mechanisms is further reported. Moreover, the evolution and results of the clinical trials of rociletinib (TIGER trials) are compared with the trials on osimertinib, another third-generation EGFR-TKI that now has been granted US Food and Drug Administration approval. The reasons behind the arrest in the further development of rociletinib are put in the perspective of future drug development.

Unravelling signal escape through maintained EGFR activation in advanced non-small cell lung cancer (NSCLC): new treatment options

The discovery of activating epidermal growth factor receptor (EGFR) mutations has opened up a new era in the development of more effective treatments for patients with non-small cell lung cancer (NSCLC). However, patients with EGFR-activating mutated NSCLC treated with EGFR tyrosine kinase inhibitors (TKIs) ultimately develop acquired resistance (AR). Among known cases of patients with AR, 70% of the mechanisms involved in the development of AR to EGFR TKI have been identified and may be categorised as either secondary EGFR mutations such as the T790M mutation, activation of bypass track signalling pathways such as MET amplification, or histologic transformation. EGFR-mutant NSCLC tumours maintain oncogenic addiction to the EGFR pathway beyond progression with EGFR TKI. Clinical strategies that can be implemented in daily clinical practice to potentially overcome this resistance and prolong the outcome in this subgroup of patients are presented.

Circulating tumour DNA profiling reveals heterogeneity of EGFR inhibitor resistance mechanisms in lung cancer patients

Circulating tumour DNA (ctDNA) analysis facilitates studies of tumour heterogeneity. Here we employ CAPP-Seq ctDNA analysis to study resistance mechanisms in 43 non-small cell lung cancer (NSCLC) patients treated with the third-generation epidermal growth factor receptor (EGFR) inhibitor rociletinib. We observe multiple resistance mechanisms in 46% of patients after treatment with first-line inhibitors, indicating frequent intra-patient heterogeneity. Rociletinib resistance recurrently involves MET, EGFR, PIK3CA, ERRB2, KRAS and RB1. We describe a novel EGFR L798I mutation and find that EGFR C797S, which arises in ∼33% of patients after osimertinib treatment, occurs in <3% after rociletinib. Increased MET copy number is the most frequent rociletinib resistance mechanism in this cohort and patients with multiple pre-existing mechanisms (T790M and MET) experience inferior responses. Similarly, rociletinib-resistant xenografts develop MET amplification that can be overcome with the MET inhibitor crizotinib. These results underscore the importance of tumour heterogeneity in NSCLC and the utility of ctDNA-based resistance mechanism assessment.

Profile of rociletinib and its potential in the treatment of non-small-cell lung cancer

Patients with non-small-cell lung cancer (NSCLC) harboring activating mutations in EGFR benefit from treatment with EGFR small-molecule tyrosine-kinase inhibitors. However, the development of acquired resistance to EGFR inhibitors is universal and limits treatment efficacy. Over half of patients receiving first-generation EGFR inhibitors (erlotinib and gefitinib) develop resistance via the gatekeeper EGFR T790M (EGFR^T790M) mutation, and therapies able to overcome T790M-mediated resistance have been an unmet need in NSCLC. Rociletinib (CO-1686) is a third-generation small-molecule EGFR inhibitor with potent activity against EGFR^T790M currently in advanced clinical development in NSCLC. Early clinical data suggested significant activity in EGFR-mutant NSCLC harboring T790M alterations. However, important questions regarding side-effect profile, comparability to competitor compounds, acquired resistance, EGFR-therapy sequencing, and combination therapies remain. Here, we review the available preclinical and clinical data for rociletinib, highlight the comparison to other third-generation EGFR inhibitors, and discuss resistance implications and future directions in NSCLC.

The safety and efficacy of osimertinib for the treatment of EGFR T790M mutation positive non-small-cell lung cancer

First- and second-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) are the evidence-based first-line treatment for metastatic non-small-cell lung cancers (NSCLCs) that harbor sensitizing EGFR mutations (i.e. exon 19 deletions or L858R). However, acquired resistance to EGFR TKI monotherapy occurs invariably within a median time frame of one year. The most common form of biological resistance is through the selection of tumor clones harboring the EGFR T790M mutation, present in >50% of repeat biopsies. The presence of the EGFR T790M mutation negates the inhibitory activity of gefitinib, erlotinib, and afatinib. A novel class of third-generation EGFR TKIs has been identified by probing a series of covalent pyrimidine EGFR inhibitors that bind to amino-acid residue C797 of EGFR and preferentially inhibit mutant forms of EGFR versus the wild-type receptor. We review the rapid clinical development and approval of the third-generation EGFR TKI osimertinib for treatment of NSCLCs with EGFR-T790M.

Targeted Therapy in Brain Metastases: Ready for Primetime?

Brain metastasis is a serious complication of cancer that causes significant morbidity for patients. Over the last decade, numerous new driver somatic mutations have been recognized and targeted therapies are changing the landscape of treatment in lung cancer, breast cancer, and melanoma, which are also the three most common cancers that result in brain metastases. The common actionable mutations include the EGFR mutation and anaplastic lymphoma kinase (ALK) translocations in non-small cell lung cancer, the HER2 mutation in breast cancer, and the BRAF mutation in melanoma. However, most of the early trials with targeted agents excluded patients with brain metastases. With a better understanding of the biology, several recent trials of targeted therapy that focus on brain metastases have been reported and others are ongoing. Novel agents with better penetration across the blood-brain barrier are currently being investigated for patients with brain metastases. In this review, we discuss the current state of use and future directions of targeted therapies in brain metastases.