Tackling ALK in non-small cell lung cancer: the role of novel inhibitors

Precision nanomedicine to treat non-small cell lung cancer

Lung cancer is a major cause of death worldwide, being often detected at a later stage due to the non-appearance of early symptoms. Therefore, specificity of the treatment is of utmost importance for its effective treatment. Precision medicine is a personalized therapy based on the genomics of the patient to design a suitable drug approach. Genetic mutations render the tumor resistant to specific mutations and the therapy is in vain even though correct medications are prescribed. Therefore, Precision medicine needs to be explored for the treatment of Non-small cell lung cancer (NSCLC). Nanoparticles are widely explored to give personalized interventions to treat lung cancer due to their various advantages like the ability to reach cancer cells, enhanced permeation through tissues, specificity, increased bioavailability, etc. Various nanoparticles (NPs) including gold nanoparticles, carbon nanotubes, aptamer-based NPs etc. were conjugated with biomarkers/diagnostic agents specific to cancer type and were delivered. Various biomarker genes have been identified through precision techniques for the diagnosis and treatment of NSCLC like EGFR, RET, KRAS, ALK, ROS-1, NTRK-1, etc. By incorporating of drug with the nanoparticle through bioconjugation, the specificity of the treatment can be enhanced with this revolutionary treatment. Additionally, integration of theranostic cargos in the nanoparticle would allow diagnosis as well as treatment by targeting the site of disease progression. Therefore, to target NSCLC effectively precision nanomedicine has been adopted in recent times. Here, we present different nanoparticles that are used as precision nanomedicine and their effectiveness against NSCLC disease.

Lorlatinib as a treatment for ALK-positive lung cancer

Lorlatinib, a third-generation ALK tyrosine kinase inhibitor, has been approved as a treatment for ALK-positive lung cancer. This review provides information regarding the pharmacology and clinical features of lorlatinib, including its efficacy and associated adverse events. Pivotal clinical trials are discussed along with the current status of lorlatinib as a treatment for ALK-positive lung cancer and future therapeutic challenges.

Discovery of LYC-55716: A Potent, Selective, and Orally Bioavailable Retinoic Acid Receptor-Related Orphan Receptor-γ (RORγ) Agonist for Use in Treating Cancer

Retinoic acid receptor-related orphan receptor γ (RORc, RORγ, or NR1F3) is the nuclear receptor master transcription factor that drives the function and development of IL-17-producing T helper cells (Th17), cytotoxic T cells (Tc17), and subsets of innate lymphoid cells. Activation of RORγ+ T cells in the tumor microenvironment is hypothesized to render immune infiltrates more effective at countering tumor growth. To test this hypothesis, a family of benzoxazines was optimized to provide LYC-55716 (37c), a potent, selective, and orally bioavailable small-molecule RORγ agonist. LYC-55716 decreases tumor growth and enhances survival in preclinical tumor models and was nominated as a clinical development candidate for evaluation in patients with solid tumors.

STRN-ALK Fusion in Lung Adenocarcinoma with Excellent Response Upon Alectinib Treatment: A Case Report and Literature Review

Non-small cell lung cancer (NSCLC) patients with anaplastic lymphoma kinase (ALK) rearrangement benefit from treatment with ALK inhibitors. Therefore, the identification of druggable ALK fusions is necessary for NSCLC treatment. More than 90 fusion partners of ALK have been reported in NSCLC patients, but the striatin gene (STRN)-ALK fusion has rarely been reported. Moreover, the response of STRN-ALK fusion patients treated with ALK inhibitors remains to be explored. A 64-year-old Chinese male with no history of smoking or alcohol consumption was diagnosed as stage IVB lung adenocarcinoma (LADC) (cT4N3M1c) in October 2018. Next-generation sequencing (NGS) targeting 425 cancer-related genes was performed on the plasma and supernatant of pleural effusion samples and revealed an STRN-ALK fusion. The patient received alectinib (600 mg, twice daily) as the first-line treatment with an excellent response exceeding 19 months. This is the first report of a NSCLC patient harboring an STRN-ALK fusion and exhibiting an excellent response to alectinib treatment. This case provides valuable information for therapeutic decision-making of patients with STRN-ALK fusions. Furthermore, this case also highlighted the advantage of performing targeted NGS on circulating tumor DNA for the identification and analysis of rare, druggable genomic alterations.

Focus on ROS1-Positive Non-Small Cell Lung Cancer (NSCLC): Crizotinib, Resistance Mechanisms and the Newer Generation of Targeted Therapies

Simple Summary

Genetic rearrangements of the ROS1 gene account for up to 2% of NSCLC patients who sometimes develop brain metastasis, resulting in poor prognosis. This review discusses the tyrosine kinase inhibitor crizotinib plus updates and preliminary results with the newer generation of tyrosine kinase inhibitors, which have been specifically conceived to overcome crizotinib resistance, including brigatinib, cabozantinib, ceritinib, entrectinib, lorlatinib and repotrectinib. After introducing each agent’s properties, we provide suggestions on the best approaches to identify resistance mechanisms at an early stage, and we speculate on the most appropriate second-line therapies for patients who reported disease progression following crizotinib administration.

Abstract

The treatment of patients affected by non-small cell lung cancer (NSCLC) has been revolutionised by the discovery of druggable mutations. ROS1 (c-ros oncogene) is one gene with druggable mutations in NSCLC. ROS1 is currently targeted by several specific tyrosine kinase inhibitors (TKIs), but only two of these, crizotinib and entrectinib, have received Food and Drug Administration (FDA) approval. Crizotinib is a low molecular weight, orally available TKI that inhibits ROS1, MET and ALK and is considered the gold standard first-line treatment with demonstrated significant activity for lung cancers harbouring ROS1 gene rearrangements. However, crizotinib resistance often occurs, making the treatment of ROS1-positive lung cancers more challenging. A great effort has been undertaken to identify a new generation or ROS1 inhibitors. In this review, we briefly introduce the biology and role of ROS1 in lung cancer and discuss the underlying acquired mechanisms of resistance to crizotinib and the promising new agents able to overcome resistance mechanisms and offer alternative efficient therapies.

Emergence of a HER2-amplified clone during disease progression in an ALK-rearranged NSCLC patient treated with ALK-inhibitors: a case report

Anaplastic lymphoma kinase tyrosine kinase inhibitors (ALK-TKIs) are the standard treatment for advanced ALK-positive non-small cell lung cancer (NSCLC) allowing survivals up to 5 years. However, duration of responses is limited by the almost certain occurrence of drug resistance. Here, we report a case of a never smoker, 59-year-old female with metastatic ALK-positive adenocarcinoma, solid and signet ring patterns, who developed resistance to alectinib, a second-generation ALK-TKI, mediated by HER2 gene amplification. The patient received 22 months of crizotinib as first-line and subsequently 1-year of alectinib therapy. A study of resistance mechanism was performed with next generation sequencing (NGS) on tissue re-biopsy. A HER2-amplified emerging clone was identified by NGS in a liver metastasis and confirmed by fluorescent in situ hybridization (FISH) analysis. The resistant clone was detectable 2 months before disease progression in plasma cell-free DNA (cfDNA) using digital droplet PCR (ddPCR) copy number variation (CNV) assay and it was retrospectively traced in rare cells of the lung primary by FISH. To our best knowledge, this is first evidence of HER2 gene amplification as a resistance mechanism to ALK-TKI in a NSCLC. Future strategies against oncogene-addicted NSCLC might benefit of combined drug treatments, such as ALK and HER2 inhibition.

Density Functional Theory and Molecular Simulation Studies for Prioritizing Anaplastic Lymphoma Kinase Inhibitors

Targeting anaplastic lymphoma kinase (ALK) is one of the important treatment strategies for the treatment of non-small cell lung cancer (NSCLC). In the present perspective, multidimensional approaches were used for the identification of ALK inhibitors. Initially, an e-pharmacophore model was generated using the PHASE algorithm and was used as a 3D query to screen 468,200 molecules of ASINEX database. Prior to the screening process, the model was evaluated for its significance and the ability to differentiate actives from inactives, using enrichment analysis. Subsequently, the hierarchical docking protocol and binding free energy calculations were instigated using GLIDE algorithm and Prime module, respectively. Further, the pharmacokinetic/pharmacodynamics (PK/PD) properties and toxicities of the hit compounds were envisaged respectively using QikProp program, Osiris explorer, and Protox-II algorithm. These approaches retrieved two hits namely BAS 00137817 and BAS 00680055 with acceptable absorption, distribution, metabolism, excretion and toxicity (ADMET) properties and higher affinity towards ALK protein. Additionally, density functional theory calculations and molecular dynamics simulations were performed to validate the inhibitory activity of the lead compounds. It is noteworthy to mention that all the hits constitute of particular scaffolds which play a major role in the downregulation of some ALK-positive lung cancer pathways. We speculate that the outcomes of this research are of substantial prominence in the rational designing of novel and efficacious ALK inhibitors.

Acquired Resistance Mutations to ALK Inhibitors Identified by Single Circulating Tumor Cell Sequencing in ALK-Rearranged Non-Small-Cell Lung Cancer

PURPOSE

Patients with anaplastic lymphoma kinase (ALK)-rearranged non-small-cell lung cancer (NSCLC) inevitably develop resistance to ALK inhibitors. New diagnostic strategies are needed to assess resistance mechanisms and provide patients with the most effective therapy. We asked whether single circulating tumor cell (CTC) sequencing can inform on resistance mutations to ALK inhibitors and underlying tumor heterogeneity in ALK-rearranged NSCLC.

EXPERIMENTAL DESIGN

Resistance mutations were investigated in CTCs isolated at the single-cell level from patients at disease progression on crizotinib (n = 14) or lorlatinib (n = 3). Three strategies including filter laser-capture microdissection, fluorescence activated cell sorting, and the DEPArray were used. One hundred twenty-six CTC pools and 56 single CTCs were isolated and sequenced. Hotspot regions over 48 cancer-related genes and 14 ALK mutations were examined to identify ALK-independent and ALK-dependent resistance mechanisms.

RESULTS

Multiple mutations in various genes in ALK-independent pathways were predominantly identified in CTCs of crizotinib-resistant patients. The RTK-KRAS (EGFR, KRAS, BRAF genes) and TP53 pathways were recurrently mutated. In one lorlatinib-resistant patient, two single CTCs out of 12 harbored ALK compound mutations. CTC-1 harbored the ALK ^{G1202R/F1174C} compound mutation virtually similar to ALK ^{G1202R/F1174L} present in the corresponding tumor biopsy. CTC-10 harbored a second ALK ^{G1202R/T1151M} compound mutation not detected in the tumor biopsy. By copy-number analysis, CTC-1 and the tumor biopsy had similar profiles, whereas CTC-10 harbored multiple copy-number alterations and whole-genome duplication.

CONCLUSIONS

Our results highlight the genetic heterogeneity and clinical utility of CTCs to identify therapeutic resistance mutations in ALK-rearranged patients. Single CTC sequencing may be a unique tool to assess heterogeneous resistance mechanisms and help clinicians for treatment personalization and resistance options to ALK-targeted therapies.

Brigatinib: New-generation ALK inhibitor for nonsmall cell lung cancer

Lung cancer, specifically nonsmall cell lung cancer (NSCLC) is the leading cause of death around the world. First-line therapies for metastatic NSCLC such as crizotinib, a tyrosine kinase inhibitor (TKI), have developed resistance due to a rearrangement of the anaplastic lymphoma kinase (ALK) gene. Brigatinib, approved in May 2016, is an ALK inhibitor specifically indicated for ALK-positive metastatic NSCLC in patients who have progressed on or resistant to crizotinib therapy. In several clinical trials, brigatinib has exhibited significant improvement in progression-free survival in patients that have experienced resistance to crizotinib therapy. The optimal dose of brigatinib was found to be 180 mg once daily and demonstrated greater efficacy as compared to its 90 mg once daily dose. Brigatinib was also found to be well tolerated. Although more studies are needed, the current data from these studies indicate brigatinib may be the most favorable therapeutic approach to treat NSCLC ALK-positive patients.

Expression of C-terminal ALK, RET, or ROS1 in lung cancer cells with or without fusion

Background

Genetic alterations, including mutation of epidermal growth factor receptor or v-Ki-ras2 kirsten rat sarcoma viral oncogene homolog and fusion of anaplastic lymphoma kinase (ALK), RET proto-oncogene (RET), or v-ros UR2 sarcoma virus oncogene homolog 1 (ROS1), occur in non-small cell lung cancers, and these oncogenic drivers are important biomarkers for targeted therapies. A useful technique to screen for these fusions is the detection of native carboxy-terminal (C-terminal) protein by immunohistochemistry; however, the effects of other genetic alterations on C-terminal expression is not fully understood. In this study, we evaluated whether C-terminal expression is specifically elevated by fusion with or without typical genetic alterations of lung cancer.

Methods

In 37 human lung cancer cell lines and four tissue specimens, protein and mRNA levels were measured by capillary western blotting and reverse transcription–PCR, respectively.

Results

Compared with the median of all 37 cell lines, mRNA levels at the C-terminus of all five of the fusion-positive cell lines tested (three ALK, one RET, and one ROS1) were elevated at least 2000-, 300-, or 2000-fold, respectively, and high C-terminal protein expression was detected. In an ALK fusion–positive tissue specimen, the mRNA and protein levels of C-terminal ALK were also markedly elevated. Meanwhile, in one of 36 RET fusion–negative cell lines, RET mRNA levels at the C-terminus were elevated at least 500-fold compared with the median of all 37 cell lines, and high C-terminal protein expression was detected despite the absence of RET fusion.

Conclusions

This study of 37 cell lines and four tissue specimens shows the detection of C-terminal ALK or ROS1 proteins could be a comprehensive method to determine ALK or ROS1 fusion, whereas not only the detection of C-terminal RET protein but also other methods would be needed to determine RET fusion.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5527-2) contains supplementary material, which is available to authorized users.

Drug-resistance mechanisms of three mutations in anaplastic lymphoma kinase against two inhibitors based on MM/PBSA combined with interaction entropy

As a promising drug target in the treatment of lung cancer, anaplastic lymphoma kinase (ALK) and its mutations have been studied widely. This work explored the origin of the resistance mechanism of the ALK mutants again two inhibitors.

Ventana ALK (D5F3) in the Detection of Patients Affected by Anaplastic Lymphoma Kinase-positive Non-Small-cell Lung Cancer: Clinical and Budget Effect

BACKGROUND

To ensure identification of anaplastic lymphoma kinase-positive (ALK⁺) patients, the Italian Drug Agency suggested a testing algorithm based on the use of fluorescence in situ hybridization (FISH) and/or immunohistochemistry. The aim was to evaluate the clinical and economic effects of adopting an immunohistochemical test (Ventana ALK D5F3) as an option for detecting ALK protein expression in advanced non-small cell lung cancer (NSCLC) patients.

MATERIALS AND METHODS

A budget impact model was developed by adopting the Italian National Health Service (NHS) perspective and a 5-year period to compare 2 scenarios: the current use of D5F3 (28%; current scenario) and increased use of D5F3 (60%; alternative scenario). The testing cost and the number and cost of the identified ALK⁺ patients were evaluated.

RESULTS

A more extensive use of D5F3 in the alternative scenario showed a decrease in diagnostic costs of ∼€468,000 compared with current scenario when considering all advanced NSCLC patients. If these savings were allocated to test more NSCLC patients (75% vs. 53%), an incremental cost per identified ALK⁺ patient of €63 would be required, leading to an overall survival gain for the alternative scenario compared with the current scenario (32.4 vs. 27.1 months; relative increase, 20%).

CONCLUSION

The use of D5F3 would provide a cost savings for the NHS owing to a lower acquisition cost than FISH and a comparable detection rate. The savings could be reinvested to test a greater number of patients, leading to more efficient identification, use of targeted therapy, and improvement in clinical outcomes of ALK⁺ patients.

Resistance Mechanisms to Targeted Therapies in ROS1+ and ALK+ Non-small Cell Lung Cancer

Purpose: Despite initial benefit from tyrosine kinase inhibitors (TKIs), patients with advanced non-small cell lung cancer (NSCLC) harboring ALK (ALK⁺) and ROS1 (ROS1⁺) gene fusions ultimately progress. Here, we report on the potential resistance mechanisms in a series of patients with ALK⁺ and ROS1⁺ NSCLC progressing on different types and/or lines of ROS1/ALK-targeted therapy.Experimental Design: We used a combination of next-generation sequencing (NGS), multiplex mutation assay, direct DNA sequencing, RT-PCR, and FISH to identify fusion variants/partners and copy-number gain (CNG), kinase domain mutations (KDM), and copy-number variations (CNVs) in other cancer-related genes. We performed testing on 12 ROS1⁺ and 43 ALK⁺ patients.Results: One of 12 ROS1⁺ (8%) and 15 of 43 (35%) ALK ⁺ patients harbored KDM. In the ROS1⁺ cohort, we identified KIT and β-catenin mutations and HER2-mediated bypass signaling as non-ROS1-dominant resistance mechanisms. In the ALK⁺ cohort, we identified a novel NRG1 gene fusion, a RET fusion, 2 EGFR, and 3 KRAS mutations, as well as mutations in IDH1, RIT1, NOTCH, and NF1 In addition, we identified CNV in multiple proto-oncogenes genes including PDGFRA, KIT, KDR, GNAS, K/HRAS, RET, NTRK1, MAP2K1, and others.Conclusions: We identified a putative TKI resistance mechanism in six of 12 (50%) ROS1 ⁺ patients and 37 of 43 (86%) ALK⁺ patients. Our data suggest that a focus on KDMs will miss most resistance mechanisms; broader gene testing strategies and functional validation is warranted to devise new therapeutic strategies for drug resistance. Clin Cancer Res; 24(14); 3334-47. ©2018 AACR.

Novel Molecular Challenges in Targeting Anaplastic Lymphoma Kinase in ALK-Expressing Human Cancers

Targeting anaplastic lymphoma kinase (ALK), a receptor tyrosine kinase receptor initially identified as a potent oncogenic driver in anaplastic large-cell lymphoma (ALCL) in the form of nucleophosmin (NPM)-ALK fusion protein, using tyrosine kinase inhibitors has shown to be a promising therapeutic approach for ALK-expressing tumors. However, clinical resistance to ALK inhibitors invariably occurs, and the molecular mechanisms are incompletely understood. Recent studies have clearly shown that clinical resistance to ALK inhibitors is a multifactorial and complex mechanism. While few of the mechanisms of clinical resistance to ALK inhibitors such as gene mutation are well known, there are others that are not well covered. In this review, the molecular mechanisms of cancer stem cells in mediating resistance to ALK inhibitors as well as the current understanding of the molecular challenges in targeting ALK in ALK-expressing human cancers will be discussed.

Lung Toxicity in Non-Small-Cell Lung Cancer Patients Exposed to ALK Inhibitors: Report of a Peculiar Case and Systematic Review of the Literature

Lung toxicity is a potential fatal effect involving non-small-cell lung cancer (NSCLC) patients exposed to tyrosine kinase inhibitors (TKIs). Moving from our experience regarding a patient who developed lung toxicity while receiving 2 different anaplastic lymphoma kinase (ALK)-TKIs, we performed a systematic review to assess the epidemiologic magnitude and the clinical significance of such toxicity in NSCLC patients treated with ALK-TKIs. Studies were identified using MEDLINE and additional sources (European Society for Medical Oncology, American Society of Clinical Oncology, and World Conference on Lung Cancer abstracts) in agreement with Preferred Reporting Items for Systematic Reviews and Meta-Analyses and Cochrane guidelines. Lung toxicity was reported in 105 of 4943 NSCLC patients (2.1%). Crizotinib was responsible for pulmonary adverse events (AEs) in 1.8% of exposed patients (49 of 2706). With the limit of a lower number of treated patients (n = 359), brigatinib resulted as the most frequently involved in lung toxicity (7%; n = 25). Pulmonary AEs during therapy with ceritinib, alectinib, and lorlatinib occurred in 1.1%, 2.6%, and 1.8% of the patients, respectively. Sixty-five percent of cases accounted for Grade 3 or 4 events, with a mortality rate of 9%. Radiological patterns of pneumonia were reported in 25 patients, whereas imaging evocative of interstitial lung disease in 37. Overall, 26 of 105 patients (25%) permanently discontinued treatment because of lung toxicity. Lung toxicity is a rare albeit potentially severe side effect in NSCLC patients receiving ALK-TKIs, apparently more frequent with brigatinib. Its early recognition and treatment are crucial for the best outcome of this subgroup of patients, whose overall prognosis is being improved by the availability of several targeted agents.

Effects of SMYD2-mediated EML4-ALK methylation on the signaling pathway and growth in non-small-cell lung cancer cells

A specific subtype of non-small-cell lung cancer (NSCLC) characterized with an EML4-ALK fusion gene, which drives constitutive oncogenic activation of anaplastic lymphoma kinase (ALK), shows a good clinical response to ALK inhibitors. We have reported multiple examples implying the biological significance of methylation on non-histone proteins including oncogenic kinases in human carcinogenesis. Through the process to search substrates for various methyltransferases using an in vitro methyltransferase assay, we found that a lysine methyltransferase, SET and MYND domain-containing 2 (SMYD2), could methylate lysine residues 1451, 1455, and 1610 in ALK protein. Knockdown of SMYD2 as well as treatment with a SMYD2 inhibitor in two NSCLC cell lines with an EML4-ALK gene significantly attenuated the phosphorylation levels of the EML4-ALK protein. Substitutions of each of these three lysine residues to an alanine partially or almost completely diminished in vitro methylation of ALK. In addition, we found that exogenous introduction of EML4-ALK protein with the substitution of lysine 1610 to an alanine in these two cell lines reduced the phosphorylation levels of AKT, one of the downstream oncogenic molecules in the EML4-ALK pathway, and suppressed the growth of the two cell lines. We further showed that the combination of a SMYD2 inhibitor and an ALK inhibitor additively suppressed the growth of these two NSCLC cells, compared with single-agent treatment. Our results shed light on a novel mechanism that modulates the kinase activity of the ALK fused gene product and imply that SMYD2-mediated ALK methylation might be a promising target for development of a novel class of treatment for tumors with the ALK fused gene.

Leptomeningeal disease: current diagnostic and therapeutic strategies

Leptomeningeal disease has become increasingly prevalent as novel therapeutic interventions extend the survival of cancer patients. Although a majority of leptomeningeal spread occurs secondary to breast cancer, lung cancer, and melanoma, a wide variety of malignancies have been reported as primary sources. Symptoms on presentation are equally diverse, often involving a combination of neurological deficits with the possibility of obstructive hydrocephalus. Diagnosis is definitively made via cerebrospinal fluid cytology for malignant cells, but neuro-imaging with high quality T1-weighted magnetic resonance imaging can aid diagnosis and localization. While leptomeningeal disease is still a terminal, late-stage complication, a variety of treatment modalities, such as intrathecal chemotherapeutics and radiation therapy, have improved median survival from 4–6 weeks to 3–6 months. Positive prognosticative factors for survival include younger age, high performance scores, and controlled systemic disease. In looking to the future, diagnostics that improve early detection and chemotherapeutics tailored to the primary malignancy will likely be the most significant advances in improving survival.

The second-generation ALK inhibitor alectinib effectively induces apoptosis in human neuroblastoma cells and inhibits tumor growth in a TH-MYCN transgenic neuroblastoma mouse model

Activating germline mutations of anaplastic lymphoma kinase (ALK) occur in most cases of hereditary neuroblastoma (NB) and the constitutively active kinase activity of ALK promotes cell proliferation and survival in NB. Therefore, ALK kinase is a potential therapeutic target for NB. In this study, we show that the novel ALK inhibitor alectinib effectively suppressed cell proliferation and induces apoptosis in NB cell lines with either wild-type ALK or mutated ALK (F1174L and D1091N) by blocking ALK-mediated PI3K/Akt/mTOR signaling. In addition, alectinib enhanced doxorubicin-induced cytotoxicity and apoptosis in NB cells. Furthermore, alectinib induced apoptosis in an orthotopic xenograft NB mouse model. Also, in the TH-MYCN transgenic mouse model, alectinib resulted in decreased tumor growth and prolonged survival time. These results indicate that alectinib may be a promising therapeutic agent for the treatment of NB.

Update on targeted therapies for advanced non-small cell lung cancer: nivolumab in context

While the initial treatment of non-small cell lung cancer (NSCLC) usually relies on surgical resection followed by systemic cytotoxic chemotherapy and/or radiation therapy, recent advances in understanding of NSCLC biology and immunology have spurred the development of numerous targeted therapies. In particular, a class of immune modulatory drugs targeting the immune checkpoint pathways has demonstrated remarkable durable remissions in a select minority of advanced NSCLC patients, potentially heralding the elusive “cancer cure”. This review focuses on the clinical evidence for one of these agents, nivolumab, and clarifies the role of this drug in the context of the other targeted therapies currently available for the treatment of NSCLC. We also discuss the impact of nivolumab on patient quality of life and health economics.

Best Practices in Treatment Selection for Patients With Advanced NSCLC

Worldwide, lung cancer is the most prevalent form of cancer, and its non-small-cell subtype constitutes up to 85% of cases. Overall, lung cancer is the most common cause of cancer-related death in the United States for both sexes, and its 5-year survival rate is 17%. It is a heterogeneous disease characterized by a variety of biomarkers and differing histologies. Non-small-cell lung cancer may be squamous or nonsquamous in nature and fueled by a number of oncodrivers. Obtaining sufficient tissue during biopsy to perform thorough biomarker testing is a challenge but essential for the modern, targeted therapeutic environment. Although platinum-based doublets still play a major role in first-line treatment, novel therapeutic agent targeting BRAF, EGFR, ALK, and ROS1, as well as agents targeting the T790M mutation, may offer options for patients whose disease fails to respond to initial therapy or relapses following an initial response. The emergence of immunotherapy as second-line standard therapy has changed the treatment paradigm. Some patients will have more favorable outcomes in the first-line setting with immunotherapy. However, managing lung cancer has become more complex than it was 15 years ago when the challenge of treatment was seen as being only binary, ie, small-cell vs non-small-cell disease.

Treating patients with ALK-rearranged non-small-cell lung cancer: mechanisms of resistance and strategies to overcome it

Anaplastic lymphoma kinase (ALK) rearrangement is detected in 3-7% of patients with non-small-cell lung cancer. Crizotinib is an ALK inhibitor, which was approved in 2011 for the treatment of ALK-positive lung cancer. Despite the initial enthusiasm, most of the patients develop resistance within the first year of treatment. The main mechanisms are secondary mutations and bypass track activation. Moreover, crizotinib has low penetration into the central nervous system. The need to overcome these limitations has led to the development of second-generation inhibitors that have better effectiveness against crizotinib-resistant mutations and brain metastases. Ceritinib and alectinib are the only approved drugs of this group. Many ongoing trials try to define the most appropriate agent for the treatment of ALK-positive lung cancer depending on the responsible mechanism. This review focuses on the current data regarding the potential mechanisms of resistance to ALK inhibitors and the strategies to overcome it.

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.