Resensitization to Crizotinib by the Lorlatinib ALK Resistance Mutation L1198F

Sequencing and phasing cancer mutations in lung cancers using a long-read portable sequencer

Here, we employed cDNA amplicon sequencing using a long-read portable sequencer, MinION, to characterize various types of mutations in cancer-related genes, namely, EGFR, KRAS, NRAS and NF1. For homozygous SNVs, the precision and recall rates were 87.5% and 91.3%, respectively. For previously reported hotspot mutations, the precision and recall rates reached 100%. The precise junctions of EML4-ALK, CCDC6-RET and five other gene fusions were also detected. Taking advantages of long-read sequencing, we conducted phasing of EGFR mutations and elucidated the mutational allelic backgrounds of anti-tumor drug-sensitive and resistant mutations, which could provide useful information for selecting therapeutic approaches. In the H1975 cells, 72% of the reads harbored both L858R and T790M mutations, and 22% of the reads harbored neither mutation. To ensure that the clinical requirements can be met in potentially low cancer cell populations, we further conducted a serial dilution analysis of the template for EGFR mutations. Several percent of the mutant alleles could be detected depending on the yield and quality of the sequencing data. Finally, we characterized the mutation genotypes in eight clinical samples. This method could be a convenient long-read sequencing-based analytical approach and thus may change the current approaches used for cancer genome sequencing.

Spotlight on lorlatinib and its potential in the treatment of NSCLC: the evidence to date

The identification of anaplastic lymphoma kinase (ALK), an oncogenetic driver mutation, in lung cancer has paved the way for a new era in the treatment of non-small cell lung cancer (NSCLC). Targeting ALK using tyrosine kinase inhibitors (TKI) has dramatically improved the prognosis of patients with ALK-rearranged NSCLC. However, most patients relapse on ALK-TKI therapy within a few years because of acquired resistance. One mechanism of acquiring resistance is a second mutation on the ALK gene, and the representative mutation is L1996M in the gatekeeper residue. In particular, the solvent-front ALK G1202R mutation is the common cause of resistance against first- and second-generation ALK-TKIs. Another major concern regarding ALK-TKI is metastasis to the central nervous system, commonly observed in patients relapsing after ALK-TKI therapy. The next-generation ALK inhibitor lorlatinib (PF-06463922) has therefore been developed to inhibit resistant ALK mutations, including ALK G1202R, and to penetrate the blood–brain barrier. In a Phase I/II trial, the safety and efficacy of lorlatinib were demonstrated in patients with advanced ALK-positive NSCLC, most of whom had central nervous system metastases and had previous ALK-TKI treatment. In this review, we discuss the structure, pharmacodynamics, and pharmacokinetics of lorlatinib and compare its characteristics with those of other ALK inhibitors. Furthermore, clinical trials for lorlatinib are summarized, and future perspectives in the management of patients with ALK-rearranged NSCLC are discussed.

Targeting oncogenic drivers in lung cancer: Recent progress, current challenges and future opportunities

Targeted therapies have changed the landscape of treatments for non-small cell lung cancer (NSCLC). Specific targeted therapies have been approved for NSCLC patients harboring genetic alterations in four oncogenes, and agents targeting additional oncogenic drivers are under investigation. Standard first-line chemotherapy has been supplanted by these targeted therapies due to superior efficacy and lower toxicity. Despite excellent response rates and durable responses in some cases, most patients experience relapse within a few years due to the development of acquired drug resistance. Next generation targeted therapies are being developed to overcome drug resistance and extend the duration of therapy. In this review, we summarize the current treatment strategies for the major targetable oncogenic mutations/alterations in NSCLC and discuss the mechanisms leading to acquired drug resistance.

Personalized therapy for lung cancer: striking a moving target

Molecular targeted therapy heralded a new era for the treatment of patients with oncogene-driven advanced-stage non-small-cell lung cancer (NSCLC). Molecular testing at the time of diagnosis guides therapy selection, and targeted therapies in patients with activating mutations in EGFR, BRAF, and rearrangements in anaplastic lymphoma kinase (ALK) and ROS1 have become part of routine care. These therapies have extended the median survival from a mere few months to greater than 3 years for patients with stage 4 disease. However, despite the initial success, these treatments are eventually met with molecular resistance. Selective pressure leads to cellular adaption to maintain cancer growth, making resistance complex and the treatment challenging. This review focuses on recent advances in targeted therapy, mechanisms of resistance, and therapeutic strategies to overcome resistance in patients with lung cancer.

Challenges in ALK inhibition of ALK-positive non-small-cell lung cancer: from ALK positivity detection to treatment strategies after relapse

ALK positivity, despite representing only in a small proportion of patients with non-small-cell lung cancer, is worth researching at diagnosis given the possibility to treat these patients with some targeted ALK inhibitors, which are more potent than chemotherapy. Thanks to understanding the resistance mechanisms, newer and more selective inhibitors are now available in clinical practice. Hence, this disease represents, after EGFR inhibition, a largely effective precision medicine approach. However, there are still some clinical situations in which the targeted drug seems to be ineffective. This review discusses some uncertainty about such a 'precision medicine application', focusing on some weaknesses and giving perspectives and suggestions to improve the management of this specific population.

Sarcoid-like reaction mimicking disease progression in an ALK-positive lung cancer patient receiving lorlatinib

The administration of target inhibitors is paramount to grant the longest survival in patients with ALK-positive non-small cell lung cancer (NSCLC). The eventual resistance to tyrosine kinase inhibitors (TKI) is monitored clinically and radiologically for prompt molecule shift to further generation TKI, if available. However, the early radiological detection of progression pattern (e.g. nodule onset) should be regarded with caution because overlaps exist with non-tumor cell proliferation and/or accumulation. Here we report the case of a stage IV ALK-rearranged NSCLC patient exposed to serial crizotinib, brigatinib, ceritinib, and lorlatinib (this latter brought to complete brain and leptomeningeal disease response), in a period of more than five years. During lorlatinib, the appearance of solid pulmonary nodules was obviously interpreted as disease progression. However, surgical biopsies of the pulmonary nodules revealed features of sarcoid-like granulomatous lymphadenitis, namely without tumor cell. This invasive approach, besides documenting for the first time a sarcoid-like reaction to ALK inhibitors, allowed to revert the radiological diagnosis and maintain lorlatinib, for the best patient outcome. The pragmatic relevance of these findings suggests a careful attitude towards the interpretation of radiologic patterns of disease progression in patients under TKI.

Pharmacologic characterization of CT-711, a novel dual inhibitor of ALK and c-Met

Anaplastic lymphoma kinase (ALK) is a validated molecular target for patients harboring ALK rearrangement, which triggers the development of ALK inhibitors. However, the activation of mesenchymal-epithelial transition factor (c-Met) has emerged as a common cause of acquired resistance induced by selective ALK inhibitors. Herein, we report the first preclinical characterization of CT-711, a novel dual inhibitor of ALK and c-Met. CT-711 demonstrates potent inhibitory activity against ALK kinase activity. Moreover, CT-711 profoundly inhibits ALK signal transduction and thereby induces G1 phase arrest and apoptosis, and results in remarkable anti-proliferative activity against ALK-driven cancer cells. Furthermore, CT-711 effectively inhibits c-Met kinase activity and potently overcomes the resistance mediated by c-Met activation. When orally administered to nude mice bearing xenografts, CT-711 exhibits favorable pharmacokinetic properties and robust antitumor activity. It is noteworthy that CT-711 is superior to crizotinib, the first-in-class ALK inhibitor, in the treatment of ALK-driven cancers in various models. The results of the current study provide a solid foundation for the clinical investigation of CT-711 in patients with tumors harboring ALK rearrangement.

Identification and biological evaluation of glycol diaryl ethers as novel anti-cancer agents through structure-based optimization of crizotinib

Crizotinib, a drug for anaplastic lymphoma kinase (ALK) positive and c-ros oncogene 1 receptor tyrosine kinase (ROS1) positive non-small cell lung cancer (NSCLC), was structurally optimized via a strategy of structure-based fragment replacing. Computational study showed it was beneficial for interaction of crizotinib and ALK to increase the distance between pyridyl ring and phenyl ring in crizotinib, and thus, a series of novel glycol diaryl ethers were synthesized. The in vitro anti-tumor activity of synthesized compounds was studied in NSCLC cell line H2228 and neurobalstoma cell line SH-SY5Y. Among the synthesized compounds, 9e exhibits stronger anti-cancer activity than crizotinib toward H2228 cell line with an IC₅₀ value of 0.22 μM. Molecular docking indicated that a longer chain between pyridyl ring and phenyl ring enabled molecule to have new interaction with a neighboring small hydrophobic pocket.

Structure and energy based quantitative missense variant effect analysis provides insights into drug resistance mechanisms of anaplastic lymphoma kinase mutations

Anaplastic lymphoma kinase (ALK) is considered as a validated molecular target in multiple malignancies, such as non-small cell lung cancer (NSCLC). However, the effectiveness of molecularly targeted therapies using ALK inhibitors is almost universally limited by drug resistance. Drug resistance to molecularly targeted therapies has now become a major obstacle to effective cancer treatment and personalized medicine. It is of particular importance to provide an improved understanding on the mechanisms of resistance of ALK inhibitors, thus rational new therapeutic strategies can be developed to combat resistance. We used state-of-the-art computational approaches to systematically explore the mutational effects of ALK mutations on drug resistance properties. We found the activation of ALK was increased by substitution with destabilizing mutations, creating the capacity to confer drug resistance to inhibitors. In addition, results implied that evolutionary constraints might affect the drug resistance properties. Moreover, an extensive profile of drugs against ALK mutations was constructed to give better understanding of the mechanism of drug resistance based on structural transitions and energetic variation. Our work hopes to provide an up-to-date mechanistic framework for understanding the mechanisms of drug resistance induced by ALK mutations, thus tailor treatment decisions after the emergence of resistance in ALK-dependent diseases.

P-glycoprotein (MDR1/ABCB1) restricts brain accumulation and cytochrome P450-3A (CYP3A) limits oral availability of the novel ALK/ROS1 inhibitor lorlatinib

Lorlatinib (PF-06463922) is a promising oral anaplastic lymphoma kinase (ALK) and ROS1 inhibitor currently in Phase III clinical trials for treatment of non-small-cell lung cancer (NSCLC) containing an ALK rearrangement. With therapy-resistant brain metastases a major concern in NSCLC, lorlatinib was designed to have high membrane and blood-brain barrier permeability. We investigated the roles of the multidrug efflux transporters ABCB1 and ABCG2, and the multispecific drug-metabolizing enzyme CYP3A in plasma pharmacokinetics and tissue distribution of lorlatinib using genetically modified mouse strains. In vitro, human ABCB1 and mouse Abcg2 modestly transported lorlatinib. Following oral lorlatinib administration (at 10 mg/kg), brain accumulation of lorlatinib, while relatively high in wild-type mice, was still fourfold increased in Abcb1a/1b^-/- and Abcb1a/1b;Abcg2^-/- mice, but not in single Abcg2^-/- mice. Lorlatinib plasma levels were not altered. Oral coadministration of the ABCB1/ABCG2 inhibitor elacridar increased the brain accumulation of lorlatinib in wild-type mice fourfold, that is, to the same level as in Abcb1a/1b;Abcg2^-/- mice, without altering plasma exposure. Similar results were obtained for lorlatinib testis accumulation. In Cyp3a^-/- mice, the plasma exposure of lorlatinib was increased 1.3-fold, but was then twofold reduced upon transgenic overexpression of human CYP3A4 in liver and intestine, whereas relative tissue distribution of lorlatinib remained unaltered. Our data indicate that lorlatinib brain accumulation is substantially limited by P-glycoprotein/ABCB1 in the blood-brain barrier, but this can be effectively reversed by elacridar coadministration. Moreover, oral availability of lorlatinib is markedly restricted by CYP3A4 activity. These insights may be used in optimizing the therapeutic application of lorlatinib.

Current Molecular-Targeted Therapies in NSCLC and Their Mechanism of Resistance

Lung cancer is treated with many conventional therapies, such as surgery, radiation, and chemotherapy. However, these therapies have multiple undesirable side effects. To bypass the side effects elicited by these conventional treatments, molecularly-targeted therapies are currently in use or under development. Current molecularly-targeted therapies effectively target specific biomarkers, which are commonly overexpressed in lung cancers and can cause increased tumorigenicity. Unfortunately, several molecularly-targeted therapies are associated with initial dramatic responses followed by acquired resistance due to spontaneous mutations or activation of signaling pathways. Acquired resistance to molecularly targeted therapies presents a major clinical challenge in the treatment of lung cancer. Therefore, to address this clinical challenge and to improve lung cancer patient prognosis, we need to understand the mechanism of acquired resistance to current therapies and develop additional novel therapies. This review concentrates on various lung cancer biomarkers, including EGFR, ALK, and BRAF, as well as their potential mechanisms of drug resistance.

Understanding Intratumor Heterogeneity and Evolution in NSCLC and Potential New Therapeutic Approach

Advances in innovative technology, including next-generation sequencing, have allowed comprehensive genomic analysis and the elucidation of the genomic aspect of intratumor heterogeneity (ITH). Moreover, models of the evolution of the cancer genome have been proposed by integrating these analyses. Cancer has been considered to accumulate genetic abnormalities for clonal evolution in time and space, and these evolutionary patterns vary depending on the organs of primary sites. Selection pressure is an important determinant of such evolutionary patterns. With weak selection pressure, more diverse clones coexist, and heterogeneity increases. Heterogeneity is maximized when there is no selection pressure; in other words, neutral evolution occurs. Some types of cancer such as lung cancer evolve in conditions that have maintained close to neutral evolution and produce diverse variants. This ITH is a key factor contributing to the lethal outcome of cancer, therapeutic failure, and drug resistance. This factor reaffirms the complexity and subtle adaptability of cancer. It is expected that further understanding of ITH and cancer genome evolution will facilitate the development of new therapeutic strategies to overcome ITH.

Analytical Chemistry in the Regulatory Science of Medical Devices

In the United States, regulatory science is the science of developing new tools, standards, and approaches to assess the safety, efficacy, quality, and performance of all Food and Drug Administration-regulated products. Good regulatory science facilitates consumer access to innovative medical devices that are safe and effective throughout the Total Product Life Cycle (TPLC). Because the need to measure things is fundamental to the regulatory science of medical devices, analytical chemistry plays an important role, contributing to medical device technology in two ways: It can be an integral part of an innovative medical device (e.g., diagnostic devices), and it can be used to support medical device development throughout the TPLC. In this review, we focus on analytical chemistry as a tool for the regulatory science of medical devices. We highlight recent progress in companion diagnostics, medical devices on chips for preclinical testing, mass spectrometry for postmarket monitoring, and detection/characterization of bacterial biofilm to prevent infections.

Sequential ALK Inhibitors Can Select for Lorlatinib-Resistant Compound ALK Mutations in ALK-Positive Lung Cancer

The cornerstone of treatment for advanced ALK-positive lung cancer is sequential therapy with increasingly potent and selective ALK inhibitors. The third-generation ALK inhibitor lorlatinib has demonstrated clinical activity in patients who failed previous ALK inhibitors. To define the spectrum of ALK mutations that confer lorlatinib resistance, we performed accelerated mutagenesis screening of Ba/F3 cells expressing EML4-ALK. Under comparable conditions, N-ethyl-N-nitrosourea (ENU) mutagenesis generated numerous crizotinib-resistant but no lorlatinib-resistant clones harboring single ALK mutations. In similar screens with EML4-ALK containing single ALK resistance mutations, numerous lorlatinib-resistant clones emerged harboring compound ALK mutations. To determine the clinical relevance of these mutations, we analyzed repeat biopsies from lorlatinib-resistant patients. Seven of 20 samples (35%) harbored compound ALK mutations, including two identified in the ENU screen. Whole-exome sequencing in three cases confirmed the stepwise accumulation of ALK mutations during sequential treatment. These results suggest that sequential ALK inhibitors can foster the emergence of compound ALK mutations, identification of which is critical to informing drug design and developing effective therapeutic strategies.Significance: Treatment with sequential first-, second-, and third-generation ALK inhibitors can select for compound ALK mutations that confer high-level resistance to ALK-targeted therapies. A more efficacious long-term strategy may be up-front treatment with a third-generation ALK inhibitor to prevent the emergence of on-target resistance. Cancer Discov; 8(6); 714-29. ©2018 AACR.This article is highlighted in the In This Issue feature, p. 663.

A Computational Approach for Prioritizing Selection of Therapies Targeting Drug Resistant Variation in Anaplastic Lymphoma Kinase

Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase implicated as a driver of a number of cancer types, and activates cellular pathways involved in cell proliferation and differentiation. Tyrosine kinase inhibitors (TKIs) are a small molecule therapeutic that blocks ALK function, but tumor evolution leads to the rapid emergence of drug resistant somatic variation and necessitates selection of a new treatment strategy. Computational simulations of protein:drug interactions were used to investigate the impact of seven drug resistant mutations on binding to eleven TKIs approved, or under investigation, for treatment of ALK positive cancers. The results show variant specific disruptions to TKI molecular interactions, and demonstrate the potential to aid prioritization of therapeutic interventions. Validation remains a challenge due to the complex dependence of biomolecular interactions on the local biophysical environment, but improvements to the underlying structural model and continued curation efforts will improve the clinical utility of computational predictions.

Insight into resistance mechanism of anaplastic lymphoma kinase to alectinib and JH-VIII-157-02 caused by G1202R solvent front mutation

BACKGROUND

Mutated anaplastic lymphoma kinase (ALK) drives the development of advanced non-small cell lung cancer (NSCLC). Most reported small-molecule inhibitors targeting the ALK domain do not display good inhibition of the G1202R solvent front mutation. The solvent front mutation was assumed to hinder drug binding. However, a different fact could be uncovered by the simulations reported in this study through a structural analog of alectinib (JH-VIII-157-02), which demonstrated potent effects against the G1202R mutation.

METHODS

Molecular docking, conventional molecular dynamics (MD) simulations, free energy calculations, and umbrella sampling (US) simulations were carried out to make clear the principles of the binding preferences of alectinib and JH-VIII-157-02 toward ALKWT and the ALK G1202R (ALKG1202R) mutation.

RESULTS

JH-VIII-157-02 has similar binding affinities to both ALKWT and ALKG1202R whereas it has has a much lower binding affinity for alectinib to ALKG1202R. Analysis of individual energy terms indicate the major variation involves the van der Waals and entropy terms. Structural analysis reveals that the conformational change of the ATP-binding glycine-rich loop was primarily responsible for the alectinib resistance, not JH-VIII-157-02. In addition, US simulations prove JH-VIII-157-02 has similar dissociative processes from both ALKWT and ALKG1202R, while alectinib is more easily dissociated from ALKG1202R than from ALKWT, thus indicating lesser residence time.

CONCLUSION

Both the binding affinity and the drug residence time should be emphasized in rational drug design to overcome the G1202R solvent front mutation in ALK resistance.

Xenograft tumors derived from malignant pleural effusion of the patients with non-small-cell lung cancer as models to explore drug resistance

Background

Non-small cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) mutations or anaplastic lymphoma kinase (ALK) fusions show dramatic responses to specific tyrosine kinase inhibitors (TKIs); however, after 10–12 months, secondary mutations arise that confer resistance. We generated a murine xenograft model using patient-derived NSCLC cells isolated from the pleural fluid of two patients with NSCLC to investigate the mechanisms of resistance against the ALK- and EGFR-targeted TKIs crizotinib and osimertinib, respectively.

Methods

Genotypes of patient biopsies and xenograft tumors were determined by whole exome sequencing (WES), and patients and xenograft-bearing mice received targeted treatment (crizotinib or osimertinib) accordingly. Xenograft mice were also treated for prolonged periods to identify whether the development of drug resistance and/or treatment responses were associated with tumor size. Finally, the pathology of patients biopsies and xenograft tumors were compared histologically.

Results

The histological characteristics and chemotherapy responses of xenograft tumors were similar to the actual patients. WES showed that the genotypes of the xenograft and patient tumors were similar (an echinoderm microtubule-associated protein-like 4-ALK (EML4–ALK) gene fusion (patient/xenograft: CTC15035_EML4–ALK) and EGFR L858R and T790M mutations (patient/xenograft: CTC15063_{EGFR L858R, T790M})). After continuous crizotinib or osimertinib treatment, WES data suggested that acquired ALK E1210K mutation conferred crizotinib resistance in the CTC15035_EML4–ALK xenograft, while decreased frequencies of EGFR L858R and T790M mutations plus the appearance of v-RAF murine sarcoma viral oncogene homolog B (BRAF) G7V mutations and phosphatidylinositol-4-phosphate 3-kinase catalytic subunit type 2 alpha (PIK3C2A) A86fs frame shift mutations led to osimertinib resistance in the CTC15063_{EGFR L858R, T790M} xenografts.

Conclusions

We successfully developed a new method of generating drug resistance xenograft models from liquid biopsies using microfluidic technology, which might be a useful tool to investigate the mechanisms of drug resistance in NSCLC.

Electronic supplementary material

The online version of this article (10.1186/s40880-018-0284-1) contains supplementary material, which is available to authorized users.

New insights from the widening homogeneity perspective to target intratumor heterogeneity

Precision medicine has shed new light on the treatment of heterogeneous cancer patients. However, intratumor heterogeneity strongly constrains the clinical benefit of precision medicine. Thus, rethinking therapeutic strategies from a different facet within the precision medicine framework will not only diversify clinical interventions, but also provide an avenue for precision medicine. Here, we explore the current approaches for targeting intratumor heterogeneity and their limitations. Furthermore, we propose a theoretical strategy with a "homogenization" feature based on iatrogenic evolutionary selection to target intratumor heterogeneity.

Temozolomide rechallenge in recurrent glioblastoma: when is it useful?

AIM

To identify patients with recurrent glioblastoma after temozolomide (TMZ) concurrent with and adjuvant to radiotherapy who could benefit from TMZ rechallenge at the time of disease progression.

METHODS

We retrospectively evaluated 106 glioblastoma patients who had nonprogressive disease at first magnetic resonance imaging after completion of TMZ concurrent with and adjuvant to radiotherapy, a treatment-free interval (TFI) of at least 8 weeks and received TMZ rechallenge or a nitrosourea at the time of progression.

RESULTS

In patients with TFI ≥5 months, median survival was 17.7 and 11.6 months and median progression-free survival was 8.1 and 5.8 months in the TMZ and nitrosourea group, respectively. Longer TFI was associated with reduced risk for death (p = 0.002) and for disease progression (p = 0.005).

CONCLUSION

TFI ≥5 months represents a predictor of retained TMZ sensitivity.

Antibiotic combination efficacy (ACE) networks for a Pseudomonas aeruginosa model

The spread of antibiotic resistance is always a consequence of evolutionary processes. The consideration of evolution is thus key to the development of sustainable therapy. Two main factors were recently proposed to enhance long-term effectiveness of drug combinations: evolved collateral sensitivities between the drugs in a pair and antagonistic drug interactions. We systematically assessed these factors by performing over 1,600 evolution experiments with the opportunistic nosocomial pathogen Pseudomonas aeruginosa in single- and multidrug environments. Based on the growth dynamics during these experiments, we reconstructed antibiotic combination efficacy (ACE) networks as a new tool for characterizing the ability of the tested drug combinations to constrain bacterial survival as well as drug resistance evolution across time. Subsequent statistical analysis of the influence of the factors on ACE network characteristics revealed that (i) synergistic drug interactions increased the likelihood of bacterial population extinction-irrespective of whether combinations were compared at the same level of inhibition or not-while (ii) the potential for evolved collateral sensitivities between 2 drugs accounted for a reduction in bacterial adaptation rates. In sum, our systematic experimental analysis allowed us to pinpoint 2 complementary determinants of combination efficacy and to identify specific drug pairs with high ACE scores. Our findings can guide attempts to further improve the sustainability of antibiotic therapy by simultaneously reducing pathogen load and resistance evolution.

Chemically Induced Degradation of Anaplastic Lymphoma Kinase (ALK)

We present the development of the first small molecule degraders that can induce anaplastic lymphoma kinase (ALK) degradation, including in non-small-cell lung cancer (NSCLC), anaplastic large-cell lymphoma (ALCL), and neuroblastoma (NB) cell lines. These degraders were developed through conjugation of known pyrimidine-based ALK inhibitors, TAE684 or LDK378, and the cereblon ligand pomalidomide. We demonstrate that in some cell types degrader potency is compromised by expression of drug transporter ABCB1. In addition, proteomic profiling demonstrated that these compounds also promote the degradation of additional kinases including PTK2 (FAK), Aurora A, FER, and RPS6KA1 (RSK1).

Pattern of care and survival of anaplastic lymphoma kinase rearranged non-small cell lung cancer (ALK+ NSCLC) in an Australian Metropolitan Tertiary Referral Centre: A retrospective cohort analysis

AIM

To report on the pattern of care and survival of anaplastic lymphoma kinase rearranged non-small cell lung cancer (ALK+NSCLC) in a real-world retrospective cohort from an Australian tertiary referral center.

METHODS

Individuals with a pathological diagnosis of ALK+NSCLC via immunohistochemistry and fluorescence in situ hybridization and a radiological diagnosis of stage IV disease were eligible. Patients were identified via the Pathology Department specimen database and electronic patient chart review. Data were collected and analyzed for baseline demographics, radiological pattern of disease and response to treatment, treatment sequencing, toxicity and survival.

RESULTS

Thirty-five patients were identified over a 7-year period from 2010 to 2016 and followed for a median of 23 months. Median overall survival (OS) in the entire cohort was immature at data cut, 46.0 months (95% confidence interval [CI], 22.53-69.47 months), with the longest surviving patient was alive 62.1 months since diagnosis. Objective radiological response rate overall across six potential treatments and six treatment lines (range 1-6) was 58.2%. Almost 50% received at-least two lines of ALK inhibitor therapy with median OS in this group estimated to be 53.4 months (95% CI, 35.1 months-not reached). Toxicity was manageable with a low rate of ≥ grade 3 toxicity (n = 7). Forty-eight percent relapsed within the CNS and 43% overall died due to CNS progression. In those with CNS diagnosis at baseline and/or progression within the CNS (n = 32), median OS was also 46.0 months (95% CI, 24.22-66.78 months).

CONCLUSION

This retrospective cohort analysis of a single tertiary institution experience in treating ALK+NSCLC demonstrates impressive OS and the importance and impact of careful management of CNS disease in this patient population.

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.

ALK in Neuroblastoma: Biological and Therapeutic Implications

Neuroblastoma (NB) is the most common and deadly solid tumour in children. Despite the development of new treatment options for high-risk NB, over half of patients relapse and five-year survival remains at 40-50%. Therefore, novel treatment strategies aimed at providing long-term disease remission are urgently sought. ALK, encoding the anaplastic lymphoma kinase receptor, is altered by gain-of-function point mutations in around 14% of high-risk NB and represents an ideal therapeutic target given its low or absent expression in healthy tissue postnatally. Small-molecule inhibitors of Anaplastic Lymphoma Kinase (ALK) approved in ALK fusion-positive lung cancer are currently undergoing clinical assessment in patients with ALK-mutant NB. Parallel pre-clinical studies are demonstrating the efficacy of ALK inhibitors against common ALK variants in NB; however, a complex picture of therapeutic resistance is emerging. It is anticipated that long-term use of these compounds will require combinatorial targeting of pathways downstream of ALK, functionally-related 'bypass' mechanisms and concomitant oncogenic pathways.

A molecular dynamics investigation into the mechanisms of alectinib resistance of three ALK mutants

Alectinib, a highly selective next-genetation anaplastic lymphoma kinase (ALK) inhibitor, has demonstrated promising antitumor activity in patients with ALK-positive non-small cell lung carcinomas (NSCLC). However, the therapeutic benefits of alectinib is inescapably hampered by the development of acquired resistant mutations in ALK. Despite the availability of ample experimental mutagenesis data, the molecular origin and the structural motifs under alectinib binding affinity deficiencies are still ambiguous. Here, molecular dynamics (MD) simulations and molecular mechanics generalized born surface area (MM-GBSA) calculation approaches were employed to elucidate the mechanisms of alectinib resistance induced by the mutations I1171N, V1180L, and L1198F. The MD results reveal that the studied mutations could trigger the dislocation of alectinib as well as conformational changes at the inhibitor binding site, thus induce the interactional changes between alectinib and mutants. The most influenced regions are the ligand binding entrance and the hinge region, which are considered to be the dominant binding motifs accounting for the binding affinity loss in mutants. The "key and lock mechanism" between the ethyl group at position 9 of alectinib and a recognition cavity in the hinge region of ALK is presented to illustrate the major molecular origin of drug resistance. Our results provide mechanistic insight into the effect of ALK mutations resistant to alectinib, which could contribute to further rational design of inhibitors to combat the acquired resistance.

Treating ALK-positive non-small cell lung cancer

Targeting genomic alterations, such as epidermal growth factor receptor (EGFR) mutations and anaplastic lymphoma kinase (ALK) gene rearrangements, have radically changed the treatment of patients with non-small cell lung cancer (NSCLC). In the case of ALK-rearranged gene, subsequent rapid development of effective genotype-directed therapies with ALK tyrosine kinase inhibitors (TKIs) triggered major advances in the personalized molecularly based approach of NSCLC. Crizotinib was the first-in-class ALK TKI with proven superiority over standard platinum-based chemotherapy for the 1st-line therapy of ALK-rearranged NSCLC patients. However, the acquired resistance to crizotinib and its diminished efficacy to the central nervous system (CNS) relapse led to the development of several novel ALK inhibitors, more potent and with different selectivity compared to crizotinib. To date, four ALK TKIs, crizotinib, ceritinib, alectinib and brigatinib have received approval from the Food and Drug Administration (FDA) and/or the European Medicines Agency (EMA) and even more agents are currently under investigation for the treatment of ALK-rearranged NSCLC. However, the optimal frontline approach and the exact sequence of ALK inhibitors are still under consideration. Recently announced results of phase III trials recognized higher efficacy of alectinib compared to crizotinib in first-line setting, even in patients with CNS involvement. In this review, we will discuss the current knowledge regarding the biology of the ALK-positive NSCLC, the available therapeutic inhibitors and we will focus on the raised issues from their use in clinical practise.

Cost Effectiveness of Alectinib vs. Crizotinib in First-Line Anaplastic Lymphoma Kinase-Positive Advanced Non-Small-Cell Lung Cancer

BACKGROUND

The recently completed ALEX trial demonstrated that alectinib improved progression-free survival, and delayed time to central nervous system progression compared with crizotinib in patients with anaplastic lymphoma kinase-positive non-small-cell lung cancer. However, the long-term clinical and economic impact of using alectinib vs. crizotinib has not been evaluated. The objective of this study was to determine the potential cost utility of alectinib vs. crizotinib from a US payer perspective.

METHODS

A cost-utility model was developed using partition survival methods and three health states: progression-free, post-progression, and death. ALEX trial data informed the progression-free and overall survival estimates. Costs included drug treatments and supportive care (central nervous system and non-central nervous system). Utility values were obtained from trial data and literature. Sensitivity analyses included one-way and probabilistic sensitivity analyses.

RESULTS

Treatment with alectinib vs. crizotinib resulted in a gain of 0.91 life-years, 0.87 quality-adjusted life-years, and incremental costs of US$34,151, resulting in an incremental cost-effectiveness ratio of US$39,312/quality-adjusted life-year. Drug costs and utilities in the progression-free health state were the main drivers of the model in the one-way sensitivity analysis. From the probabilistic sensitivity analysis, alectinib had a 64% probability of being cost effective at a willingness-to-pay threshold of US$100,000/quality adjusted life-year.

CONCLUSIONS

Alectinib increased time in the progression-free state and quality-adjusted life-years vs. crizotinib. The marginal cost increase was reflective of longer treatment durations in the progression-free state. Central nervous system-related costs were considerably lower with alectinib. Our results suggest that compared with crizotinib, alectinib may be a cost-effective therapy for treatment-naïve patients with anaplastic lymphoma kinase-positive non-small-cell lung cancer.

Treatment Options for Paediatric Anaplastic Large Cell Lymphoma (ALCL): Current Standard and beyond

Anaplastic Lymphoma Kinase (ALK)-positive Anaplastic Large Cell Lymphoma (ALCL), remains one of the most curable cancers in the paediatric setting; multi-agent chemotherapy cures approximately 65–90% of patients. Over the last two decades, major efforts have focused on improving the survival rate by intensification of combination chemotherapy regimens and employing stem cell transplantation for chemotherapy-resistant patients. More recently, several new and ‘renewed’ agents have offered the opportunity for a change in the paradigm for the management of both chemo-sensitive and chemo-resistant forms of ALCL. The development of ALK inhibitors following the identification of the EML4-ALK fusion gene in Non-Small Cell Lung Cancer (NSCLC) has opened new possibilities for ALK-positive ALCL. The uniform expression of CD30 on the cell surface of ALCL has given the opportunity for anti-CD30 antibody therapy. The re-evaluation of vinblastine, which has shown remarkable activity as a single agent even in the face of relapsed disease, has led to the consideration of a revised approach to frontline therapy. The advent of immune therapies such as checkpoint inhibition has provided another option for the treatment of ALCL. In fact, the number of potential new agents now presents a real challenge to the clinical community that must prioritise those thought to offer the most promise for the future. In this review, we will focus on the current status of paediatric ALCL therapy, explore how new and ‘renewed’ agents are re-shaping the therapeutic landscape for ALCL, and identify the strategies being employed in the next generation of clinical trials.

Clinical Utility of Cell-Free DNA for the Detection of ALK Fusions and Genomic Mechanisms of ALK Inhibitor Resistance in Non-Small Cell Lung Cancer

Purpose: Patients with advanced non-small cell lung cancer (NSCLC) whose tumors harbor anaplastic lymphoma kinase (ALK) gene fusions benefit from treatment with ALK inhibitors (ALKi). Analysis of cell-free circulating tumor DNA (cfDNA) may provide a noninvasive way to identify ALK fusions and actionable resistance mechanisms without an invasive biopsy.Patients and Methods: The Guardant360 (G360; Guardant Health) deidentified database of NSCLC cases was queried to identify 88 consecutive patients with 96 plasma-detected ALK fusions. G360 is a clinical cfDNA next-generation sequencing (NGS) test that detects point mutations, select copy number gains, fusions, insertions, and deletions in plasma.Results: Identified fusion partners included EML4 (85.4%), STRN (6%), and KCNQ, KLC1, KIF5B, PPM1B, and TGF (totaling 8.3%). Forty-two ALK-positive patients had no history of targeted therapy (cohort 1), with tissue ALK molecular testing attempted in 21 (5 negative, 5 positive, and 11 tissue insufficient). Follow-up of 3 of the 5 tissue-negative patients showed responses to ALKi. Thirty-one patients were tested at known or presumed ALKi progression (cohort 2); 16 samples (53%) contained 1 to 3 ALK resistance mutations. In 13 patients, clinical status was unknown (cohort 3), and no resistance mutations or bypass pathways were identified. In 6 patients with known EGFR-activating mutations, an ALK fusion was identified on progression (cohort 4; 4 STRN, 1 EML4; one both STRN and EML4); five harbored EGFR T790M.Conclusions: In this cohort of cfDNA-detected ALK fusions, we demonstrate that comprehensive cfDNA NGS provides a noninvasive means of detecting targetable alterations and characterizing resistance mechanisms on progression. Clin Cancer Res; 24(12); 2758-70. ©2018 AACR.

Reliability of using circulating tumor cells for detecting epidermal growth factor receptor mutation status in advanced non-small-cell lung cancer patients: a meta-analysis and systematic review

Purpose

To evaluate the clinical value of circulating tumor cells as a surrogate to detect epidermal growth factor receptor mutation in advanced non-small-cell lung cancer (NSCLC) patients.

Methods

We searched the electronic databases, and all articles meeting predetermined selection criteria were included in this study. The pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio were calculated. The evaluation indexes of the diagnostic performance were the summary receiver operating characteristic curve and area under the summary receiver operating characteristic curve.

Results

Eight eligible publications with 255 advanced NSCLC patients were included in this meta-analysis. Taking tumor tissues as reference, the pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio of circulating tumor cells for detecting the epidermal growth factor receptor mutation status were found to be 0.82 (95% confidence interval [CI]: 0.50–0.95), 0.95 (95% CI: 0.24–1.00), 16.81 (95% CI: 0.33–848.62), 0.19 (95% CI: 0.06–0.64), and 86.81 (95% CI: 1.22–6,154.15), respectively. The area under the summary receiver operating characteristic curve was 0.92 (95% CI: 0.89–0.94). The subgroup analysis showed that the factors of blood volume, histological type, EGFR-tyrosine kinase inhibitor therapy, and circulating tumor cell and tissue test methods for EGFR accounted for the significant difference of the pooled specificity. No significant difference was found between the pooled sensitivity of the subgroup.

Conclusion

Our meta-analysis confirmed that circulating tumor cells are a good surrogate for detecting epidermal growth factor receptor mutation when tumor tissue is unavailable in advanced NSCLC patients, but more precise techniques are needed to improve their clinical efficiency.

Capture-based ultra-deep sequencing in plasma ctDNA reveals the resistance mechanism of ALK inhibitors in a patient with advanced ALK-positive NSCLC

BACKGROUND

Anaplastic lymphoma kinase (ALK) is a validated molecular target in non-small-cell lung cancer (NSCLC). However, the clinical benefits of ALK inhibitors are almost universally limited by the emergence of drug resistance.

METHODS

We monitored the plasma circulating tumor DNA (ctDNA) using captured-based ultra-deep sequencing analysis of one patient with metastatic ALK-positive NSCLC who had received therapies including first-, second- and third-generation ALK inhibitors. Functional in vitro studies were further undertaken to elucidate the mechanism of resistance.

RESULTS

ALK T1151Sins mutation was detected when the patient developed resistance to ceritinib, and undetectable when she responded to lorlatinib. MET amplification was present when the tumor developed resistance to lorlatinib, and reduced when the patient received combination therapy of lorlatinib with crizotinib, which corresponded to clinical radiologic responses. In addition, further functional in vitro studies demonstrated that ALK harboring the T1151Sins mutation, while conferring resistance to ceritinib, was inhibited by lorlatinib.

CONCLUSIONS

Clinical evidence and in vitro validation revealed the clinical usefulness of captured-base ultra-deep sequencing on longitudinal plasma ctDNA in revealing the underlying resistance mechanism and guiding the precise administration of ALK inhibitors in patients with advanced ALK-positive NSCLC.

C3orf21 ablation promotes the proliferation of lung adenocarcinoma, and its mutation at the rs2131877 locus may serve as a susceptibility marker

In this study, we investigated the role of C3orf21 gene polymorphism at the rs2131877 locus and its contribution to lung adenocarcinoma pathogenesis. Normal lung and tumor tissue sections were collected from fifteen patients with lung adenocarcinoma for chromosome 3 open reading frame 21 (C3orf21) genotype analysis. In addition, a retrospective analysis was performed to assess the association between C3orf21 genotype and tumor markers from patient samples used in our previously published study. In parallel, we also manipulated C3orf21 gene expression either by overexpressing or ablating it in a MSTO-211H human lung cancer cell line to further understand its contribution to cell proliferation, apoptosis and migration. Our results indicated that the patients with smoking history had a significantly increased mutation (rs2131877 T/C+C/C genotype) rate (p = 0.025), in addition to higher values for the CYF211 and NSE tumor markers (p = 0.014 and p = 0.031, respectively). The retrospective analysis also confirmed that the NSE marker value was higher in patients with a C3orf21 rs2131877 T/C+C/C genotype. Furthermore, our in vitro data indicated that C3orf21 ablation promoted lung cancer cell proliferation, inhibited apoptosis and accelerated cell migration. Overall, our study concluded that C30rf21 rs 2131877 T/C+C/C genotype patients may experience increased nicotine addiction and that C30rf21 can likely serve as a susceptibility marker for lung adenocarcinoma with a higher degree of malignancy.

Primary pulmonary myoepithelial carcinoma in a young woman: A case report and review of literature

RATIONALE

Myoepithelial carcinoma mainly occurs in the salivary glands, but myoepithelial carcinoma of the lung is extremely rare neoplasm whose biological behavior and clinical course still remain to be fully elucidated. Although considered as low-grade carcinoma, these tumors have a high rate of recurrence or distant metastasis.

PATIENT CONCERNS

To date there are only 11 cases of pulmonary myoepithelial carcinoma reported in the English literature. We report a case of a 24-year-old woman diagnosed with primary pulmonary myoepithelial carcinoma. Informed consent was obtained from the patient.

DIAGNOSES

The tumor derived from superior lobe of left lung and exhibited only myoepithelial differentiation without any ductal formation by histopathological and immunohistochemical analysis.

INTERVENTIONS

The patient underwent the left superior lobe resection. In addition, we first introduce second-generation sequencing technology as a novel strategy for primary pulmonary myoepithelial carcinoma, and these tumors should be included in the differential diagnosis of thoracic neoplasms.

OUTCOMES

The patient was alive with no evidence of disease for up to 12 months.

LESSONS

Individualized treatment is the promising clinical strategy for thoracic neoplasms, and the underlying molecular events should be investigated to find the potential therapeutic targets.

Tumor Resistance against ALK Targeted Therapy-Where It Comes From and Where It Goes

Anaplastic lymphoma kinase (ALK) is a validated molecular target in several ALK-rearranged malignancies, particularly in non-small-cell lung cancer (NSCLC), which has generated considerable interest and effort in developing ALK tyrosine kinase inhibitors (TKI). Crizotinib was the first ALK inhibitor to receive FDA approval for ALK-positive NSCLC patients treatment. However, the clinical benefit observed in targeting ALK in NSCLC is almost universally limited by the emergence of drug resistance with a median of occurrence of approximately 10 months after the initiation of therapy. Thus, to overcome crizotinib resistance, second/third-generation ALK inhibitors have been developed and received, or are close to receiving, FDA approval. However, even when treated with these new inhibitors tumors became resistant, both in vitro and in clinical settings. The elucidation of the diverse mechanisms through which resistance to ALK TKI emerges, has informed the design of novel therapeutic strategies to improve patients disease outcome. This review summarizes the currently available knowledge regarding ALK physiologic function/structure and neoplastic transforming role, as well as an update on ALK inhibitors and resistance mechanisms along with possible therapeutic strategies that may overcome the development of resistance.

Synergistic activity of ALK and mTOR inhibitors for the treatment of NPM-ALK positive lymphoma

ALK-positive Anaplastic Large Cell Lymphoma (ALCL) represents a subset of Non-Hodgkin Lymphoma whose treatment benefited from crizotinib development, a dual ALK/MET inhibitor. Crizotinib blocks ALK-triggered pathways such as PI3K/AKT/mTOR, indispensable for survival of ALK-driven tumors.

Despite the positive impact of targeted treatment in ALCL, resistant clones are often selected during therapy. Strategies to overcome resistance include the design of second generation drugs and the use of combined therapies that simultaneously target multiple nodes essential for cells survival. We investigated the effects of combined ALK/mTOR inhibition. We observed a specific synergistic effect of combining ALK inhibitors with an mTOR inhibitor (temsirolimus), in ALK+ lymphoma cells. The positive cooperation resulted in an increased inhibition of mTOR effectors, compared to single treatments, a block in G0/G1 phase and induction of apoptosis. The combination was able to prevent the selection of resistant clones, while long-term exposure to single agents led to the establishment of resistant cell lines, with either ALK inhibitor or temsirolimus. In vivo, mice injected with Karpas 299 cells and treated with low dose combination showed complete regression of tumors, while only partial inhibition was obtained in single agents-treated mice. Upon treatment stop the combination was able to significantly delay tumor relapses. Re-challenge of relapsed tumors at a higher dose led to full regression of xenografts in the combination group, but not in mice treated with lorlatinib alone. In conclusion, our data suggest that the combination of ALK and mTOR inhibitors could be a valuable therapeutic option for ALK+ ALCL patients.

The function and therapeutic targeting of anaplastic lymphoma kinase (ALK) in non-small cell lung cancer (NSCLC)

Lung cancer is the leading cause of death by cancer in North America. A decade ago, genomic rearrangements in the anaplastic lymphoma kinase (ALK) receptor tyrosine kinase were identified in a subset of non-small cell lung carcinoma (NSCLC) patients. Soon after, crizotinib, a small molecule ATP-competitive ALK inhibitor was proven to be more effective than chemotherapy in ALK-positive NSCLC patients. Crizotinib and two other ATP-competitive ALK inhibitors, ceritinib and alectinib, are approved for use as a first-line therapy in these patients, where ALK rearrangement is currently diagnosed by immunohistochemistry and in situ hybridization. The clinical success of these three ALK inhibitors has led to the development of next-generation ALK inhibitors with even greater potency and selectivity. However, patients inevitably develop resistance to ALK inhibitors leading to tumor relapse that commonly manifests in the form of brain metastasis. Several new approaches aim to overcome the various mechanisms of resistance that develop in ALK-positive NSCLC including the knowledge-based alternate and successive use of different ALK inhibitors, as well as combined therapies targeting ALK plus alternative signaling pathways. Key issues to resolve for the optimal implementation of established and emerging treatment modalities for ALK-rearranged NSCLC therapy include the high cost of the targeted inhibitors and the potential of exacerbated toxicities with combination therapies.

Role and targeting of anaplastic lymphoma kinase in cancer

Anaplastic lymphoma kinase (ALK) gene activation is involved in the carcinogenesis process of several human cancers such as anaplastic large cell lymphoma, lung cancer, inflammatory myofibroblastic tumors and neuroblastoma, as a consequence of fusion with other oncogenes (NPM, EML4, TIM, etc) or gene amplification, mutation or protein overexpression.

ALK is a transmembrane tyrosine kinase receptor that, upon ligand binding to its extracellular domain, undergoes dimerization and subsequent autophosphorylation of the intracellular kinase domain. When activated in cancer it represents a target for specific inhibitors, such as crizotinib, ceritinib, alectinib etc. which use has demonstrated significant effectiveness in ALK-positive patients, in particular ALK-positive non- small cell lung cancer.

Several mechanisms of resistance to these inhibitors have been described and new strategies are underway to overcome the limitations of current ALK inhibitors.

Drug resistance in anaplastic lymphoma kinase-rearranged lung cancer

The anaplastic lymphoma kinase (ALK) gene encodes a receptor tyrosine kinase, and many kinds of ALK fusion genes have been found in a variety of carcinomas. There is almost no detectable expression of ALK in adults. However, through ALK gene rearrangement, the resultant ALK fusion protein is aberrantly overexpressed and dimerized through the oligomerization domains, such as the coiled‐coil domain, in the fusion partner that induces abnormal constitutive activation of ALK tyrosine kinase. This results in dysregulated cell proliferation. ALK gene rearrangement has been observed in 3%‐5% of non‐small‐cell lung cancers, and multiple ALK inhibitors have been developed for the treatment of ALK‐positive lung cancer. Among those inhibitors, in Japan, 3 (4 in the USA) ALK tyrosine kinase inhibitors (TKIs) have been approved and are currently used in clinics. All of the currently approved ALK‐TKIs have been shown to induce marked tumor regression in ALK‐rearranged non‐small‐cell lung cancer; however, tumors inevitably relapse because of acquired resistance within a few years. This review focuses on ALK‐TKIs, their resistance mechanisms, and the potential therapeutic strategies to overcome resistance.

Established, emerging and elusive molecular targets in the treatment of lung cancer

Although histological subtype still underlies tumour classification and treatment, the recognition that lung cancer is, largely, a genetic disease has prompted a push to reconfigure cancer taxonomies according to molecular criteria. In this review, we discuss established (e.g. EGFR, ALK, ROS1, and programmed cell death 1/programmed death-ligand 1), emerging (e.g. MET, RET, and NTRK) and elusive (e.g. TP53, KRAS, and MYC) molecular targets in the treatment of lung cancer. We synthesize a large and rapidly growing body of literature regarding the discovery and therapeutic inhibition of these targets in lung cancer. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

TKI sensitivity patterns of novel kinase-domain mutations suggest therapeutic opportunities for patients with resistant ALK+ tumors

The anaplastic lymphoma kinase (ALK) protein drives tumorigenesis in subsets of several tumors through chromosomal rearrangements that express and activate its C-terminal kinase domain. In addition, germline predisposition alleles and acquired mutations are found in the full-length protein in the pediatric tumor neuroblastoma. ALK-specific tyrosine kinase inhibitors (TKIs) have become important new drugs for ALK-driven lung cancer, but acquired resistance via multiple mechanisms including kinase-domain mutations eventually develops, limiting median progression-free survival to less than a year. Here we assess the impact of several kinase-domain mutations that arose during TKI resistance selections of ALK+ anaplastic large-cell lymphoma (ALCL) cell lines. These include novel variants with respect to ALK-fusion cancers, R1192P and T1151M, and with respect to ALCL, F1174L and I1171S. We assess the effects of these mutations on the activity of six clinical inhibitors in independent systems engineered to depend on either the ALCL fusion kinase NPM-ALK or the lung-cancer fusion kinase EML4-ALK. Our results inform treatment strategies with a likelihood of bypassing mutations when detected in resistant patient samples and highlight differences between the effects of particular mutations on the two ALK fusions.

Resisting Resistance: Targeted Therapies in Lung Cancer

Drug resistance inevitably limits the efficacy of all targeted therapies including tyrosine kinase inhibitors (TKIs). Understanding the biological underpinnings of TKI resistance is key to the successful development of future therapeutic strategies. Traditionally, mechanisms of TKI resistance have been viewed under a dichotomous lens. Tumor cells are TKI-sensitive or TKI-refractory, exhibit intrinsic or acquired resistance, and accumulate alterations within or outside the target to promote their survival. Such classifications facilitate our comprehension of an otherwise complex biology, but are likely an oversimplification. Recent studies underscore the multifaceted, genetically heterogeneous nature of TKI resistance, which evolves dynamically with changes in therapy. In this Review, we provide a broad framework for understanding the diverse mechanisms of resistance at play in oncogene-driven lung cancers.

Long-term progression-free survival in an advanced lung adenocarcinoma patient harboring EZR-ROS1 rearrangement: a case report

Background

Crizotinib is recommended as first-line therapy in ROS1-driven lung adenocarcinoma. However, the optimal first-line therapy for this subgroup of lung cancer is controversial according to the available clinical data.

Case presentation

Here, we describe a 57-year-old man who was diagnosed with stage IIIB lung adenocarcinoma and EGFR/KRAS/ALK-negative tumors. The patient received six cycles of pemetrexed plus cisplatin as first-line therapy and then pemetrexed as maintenance treatment, with a progression-free survival (PFS) of 42 months. The patient relapsed and underwent re-biopsy. EZR-ROS1 fusion mutation was detected by next-generation sequencing (NGS). The patient was prescribed crizotinib as second-line therapy and achieved a PFS of 6 months. After disease progression, lorlatinib was administered as third-line therapy, with a favorable response.

Conclusions

Prolonged PFS in patients receiving pemetrexed chemotherapy might be related to the EZR-ROS1 fusion mutation. Lorlatinib is an optimal choice in patients showing crizotinib resistance.

Does ALK-rearrangement predict favorable response to the therapy of bevacizumab plus pemetrexed in advanced non-small-cell lung cancer? Case report and literature review

Background

Advanced ALK-rearranged non-small cell lung cancer (NSCLC) patients will develop acquired resistance after anaplastic lymphoma kinase (ALK) inhibitors therapies. Vascular endothelial growth factor-A (VEGF-A) production and tumor vessel formation were found to be more significantly enriched in ALK-rearrangement NSCLC than that in epidermal growth factor receptor or Kirsten rat sarcoma viral oncogene mutated NSCLC. However, the correlation between ALK rearrangement and the efficacy of bevacizumab (a recombinant humanized IgG1 monoclonal antibody targeting VEGF-A) was still elusive.

Case presentation

We report a case with metastatic NSCLC harboring ALK-rearrangement who was initially resistant to two courses of ALK-Tyrosine Kinase Inhibitor (TKI) therapy, but got a clinical benefit of 7 months of progression free survival after the combined treatment of bevacizumab plus pemetrexed. And the patient tolerated well.

Conclusions

It suggested that bevacizumab combined with pemetrexed might be a preferred option for ALK rearrangement patient who had failed no less than two courses of ALK-TKIs.