De novo ALK kinase domain mutations are uncommon in kinase inhibitor-naïve ALK rearranged lung cancers

ALK inhibitors in cancer: mechanisms of resistance and therapeutic management strategies

Anaplastic lymphoma kinase (ALK) gene rearrangements have been identified as potent oncogenic drivers in several malignancies, including non-small cell lung cancer (NSCLC). The discovery of ALK inhibition using a tyrosine kinase inhibitor (TKI) has dramatically improved the outcomes of patients with ALK-mutated NSCLC. However, the emergence of intrinsic and acquired resistance inevitably occurs with ALK TKI use. This review describes the molecular mechanisms of ALK TKI resistance and discusses management strategies to overcome therapeutic resistance.

Primary resistance to first- and second-generation ALK inhibitors in a non-small cell lung cancer patient with coexisting ALK rearrangement and an ALK F1174L-cis-S1189C de novo mutation: A case report

The effectiveness of the tyrosine kinase inhibitor ALK (TKI) for non-small cell lung cancer has been confirmed. However, resistance to ALK-TKIs seems inevitable. Mutations in the ALK kinase domain have been reported as an important mechanism of acquired resistance to ALK therapy. However, patients with de novo ALK kinase domain mutations and ALK rearrangements who were not treated with ALK inhibitors have rarely been reported. Here, we report a case of primary drug resistance to first- and second-generation ALK inhibitors in a NSCLC patient with ALK-rearrangement. The next-generation sequencing test of the pathological biopsy showed that the de novo ALK kinase domain mutation F1174L-cis-S1189C may be the cause of primary drug resistance.

The Landscape of ALK-Rearranged Non-Small Cell Lung Cancer: A Comprehensive Review of Clinicopathologic, Genomic Characteristics, and Therapeutic Perspectives

Simple Summary

In recent years, prognosis of non-small cell lung cancer (NSCLC) patients significantly improved thanks to the introduction of tyrosine kinase inhibitors (TKIs) in clinical practice. ALK-rearranged NSCLC patients benefit from treatment with ALK inhibitors (ALK-i), which have shown a greater efficacy and a better intracranial activity than chemotherapy. Comparative studies between next-generation ALK-i are still lacking and clinicians are looking for reliable tools to determine which drug suits best for each patient. The aim of this review is to deepen the role of clinical and pathological characteristics influencing patients’ prognosis during treatment with ALK-i and to provide an overview of molecular mechanisms of ALK-i resistance. In this setting, liquid biopsy may play an important role in predicting tumor response and monitoring resistance mutations. We will summarize ongoing trials developing new ALK-i or combinations between ALK-i and other agents, which may represent future scenarios in the field of NSCLC research.

Abstract

During the last decade, the identification of oncogenic driver mutations and the introduction of tyrosine kinase inhibitors (TKIs) in daily clinical practice have substantially revamped the therapeutic approach of oncogene-addicted, non-small cell lung cancer (NSCLC). Rearrangements in the anaplastic lymphoma kinase (ALK) gene are detected in around 3–5% of all NSCLC patients. Following the promising results of Crizotinib, a first-generation ALK inhibitor (ALK-i), other second-generation and more recently third-generation TKIs have been developed and are currently a landmark in NSCLC treatment, leading to a significant improvement in patients prognosis. As clinical trials have already demonstrated high efficacy of each ALK-i, both in terms of systemic and intracranial disease control, comparative studies between second and third generation ALK-i are still lacking, and primary or secondary ALK-i resistance inevitably limit their efficacy. Resistance to ALK-i can be due to ALK-dependent or ALK-independent mechanisms, including the activation of bypass signaling pathways and histological transformation: these findings may play an important role in the future to select patients’ subsequent therapy. This review aims to provide an overview of underlying molecular alterations of ALK-i resistance and point out promising role of liquid biopsy in predicting tumor response and monitoring resistance mutations. The purpose of this review is also to summarize current approval for ALK-rearranged NSCLC patients, to help clinicians in making decisions on therapeutic sequence, and to deepen the role of clinicopathological and genomic characteristics influencing patients’ prognosis during treatment with ALK-i.

Current Knowledge about Mechanisms of Drug Resistance against ALK Inhibitors in Non-Small Cell Lung Cancer

Simple Summary

Lung cancer is a devastating disease, with non-small cell lung cancer (NSCLC) being the most common subtype. With the development of novel targeted therapeutics, survival times have continuously improved over the past two decades. In a subset of NSCLC, gene rearrangements of the anaplastic lymphoma kinase (ALK), or gene fusions involving ALK, can be determined. ALK-inhibitors are increasingly used as a standard of care in patients with ALK gene abnormalities, and can also be administered as first-line treatment in advanced-stage NSCLC. However, over the disease course, cancers tend to develop resistance mechanisms, warranting the switch from first- to second- or third-generation ALK inhibitors. With this literature review, we aim to give a concise overview about these resistance mechanisms, and what kind of sequential treatment may be feasible if therapy failure upon an ALK inhibitor occurs.

Abstract

Non-small cell lung cancer (NSCLC) accounts for the majority of lung cancer subtypes. Two to seven percent of NSCLC patients harbor gene rearrangements of the anaplastic lymphoma kinase (ALK) gene or, alternatively, harbor chromosomal fusions of ALK with echinoderm microtubule-associated protein-like 4 (EML4). The availability of tyrosine kinase inhibitors targeting ALK (ALK-TKIs) has significantly improved the progression-free and overall survival of NSCLC patients carrying the respective genetic aberrations. Yet, increasing evidence shows that primary or secondary resistance to ALK-inhibitors during the course of treatment represents a relevant clinical problem. This necessitates a switch to second- or third-generation ALK-TKIs and a close observation of NSCLC patients on ALK-TKIs during the course of treatment by repetitive molecular testing. With this review of the literature, we aim at providing an overview of current knowledge about resistance mechanisms to ALK-TKIs in NSCLC.

Detecting Resistance to Therapeutic ALK Inhibitors in Tumor Tissue and Liquid Biopsy Markers: An Update to a Clinical Routine Practice

The survival of most patients with advanced stage non-small cell lung cancer is prolonged by several months when they are treated with first- and next-generation inhibitors targeting ALK rearrangements, but resistance inevitably emerges. Some of the mechanisms of resistance are sensitive to novel ALK inhibitors but after an initial tumor response, more or less long-term resistance sets in. Therefore, to adapt treatment it is necessary to repeat biological sampling over time to look for different mechanisms of resistance. To this aim it is essential to obtain liquid and/or tissue biopsies to detect therapeutic targets, in particular for the analysis of different genomic alterations. This review discusses the mechanisms of resistance to therapeutics targeting genomic alterations in ALK as well as the advantages and the limitations of liquid biopsies for their identification.

Overcoming TKI resistance in fusion-driven NSCLC: new generation inhibitors and rationale for combination strategies

During the last several years, multiple gene rearrangements with oncogenic potential have been described in NSCLC, identifying specific clinic-pathological subgroups of patients that benefit from a targeted therapeutic approach, including anaplastic lymphoma kinase (ALK), c-ros protooncogene 1 (ROS1) and, more recently, REarranged during Transfection (RET) and neurotrophic tyrosine receptor kinases (NTRK) genes. Despite initial impressive antitumor activity, the use of targeted therapies in oncogene-addicted NSCLC subgroups is invariably associated with the development of acquired resistance through multiple mechanisms that can include both on-target and off-target mechanisms. However, the process of acquired resistance is a rapidly evolving clinical scenario that constantly evolves under the selective pressure of tyrosine kinase inhibitors. The development of increasingly higher selective and potent inhibitors, traditionally used to overcome resistance to first generation inhibitors, is associated with the development of novel mechanisms of resistance that encompass complex resistance mutations, highly recalcitrant to available TKIs, and bypass track mechanisms. Herein, we provide a comprehensive overview on the therapeutic strategies for overcoming acquired resistance to tyrosine kinase inhibitors (TKIs) targeting the most well-established oncogenic gene fusions in advanced NSCLC, including ALK, ROS1, RET, and NTRK rearrangements.

ALK-Rearranged Non-Small Cell Lung Cancer in 2020: Real-World Triumphs in an Era of Multigeneration ALK-Inhibitor Sequencing Informed by Drug Resistance Profiling

Since its discovery in 2007, we have seen the lives of patients diagnosed with advanced anaplastic lymphoma kinase (ALK)-rearranged non-small cell lung cancers (NSCLC) transform with the advent of molecular therapies with first-, second-, and third-generation ALK inhibitors now available in the clinic. Despite great gains in patient survival now measured in years and preserved quality of life with targeted therapies, drug resistance is unfortunately inevitably encountered in this rare and unique molecular subset of lung cancer, and patients will eventually succumb to the disease. As these patients are often young, fit, and never smokers, the clinical and scientific communities have aligned to expedite drug development and access. Drug resistance profiling and further strategies are being explored through clinical trials, including the evaluation of specific drug sequencing and combinations to overcome such resistance and promote patient longevity. The cases of this report focus on precision medicine and aim to portray the pertinent aspects to consider when treating ALK-rearranged NSCLC in 2020, an ever-shifting space. By way of case examples, this report offers valuable information to the treating clinician, including the evolution of systemic treatments and the management of oligo-progression and multisite drug resistance. With the maturation of real-world data, we are fortunate to be experiencing quality and length of life for patients with this disease surpassing prior expectations in advanced lung cancer. KEY POINTS: This report focuses on the importance of genetic analysis of serial biopsies to capture the dynamic therapeutic vulnerabilities of a patient's tumor, providing a perspective on the complexity of ALK tyrosine kinase inhibitor (ALKi) treatment sequencing. These case examples contribute to the literature on ALK-rearranged and oncogene addicted non-small cell lung cancer (NSCLC), providing a framework for care in the clinic. In oligo-progressive disease, local ablative therapy and continuation of ALKi postprogression should be considered with potential for sustained disease control. ALK G1202R kinase domain mutations (KDM), highly prevalent at resistance to second-generation ALKi resistances, may emerge in non-EML4-ALK variant 3 cases and is sensitive to third-generation lorlatinib. When in compound with one or more ALK KDMs, resistance to lorlatinib is expected. In the case of rampantly progressive disease, rebiopsy and redefining biology in a timely manner may be informative.

Clinical Relevance of an Amplicon-Based Liquid Biopsy for Detecting ALK and ROS1 Fusion and Resistance Mutations in Patients With Non-Small-Cell Lung Cancer

PURPOSE

Liquid biopsy specimen genomic profiling is integrated in non-small-cell lung cancer (NSCLC) guidelines; however, data on the clinical relevance for ALK /ROS1 alterations are scarce. We evaluated the clinical utility of a targeted amplicon-based assay in a large prospective cohort of patients with ALK/ROS1-positive NSCLC and its impact on outcomes.

PATIENTS AND METHODS

Patients with advanced ALK/ROS1-positive NSCLC were prospectively enrolled in the study by researchers at eight French institutions. Plasma samples were analyzed using InVisionFirst-Lung and correlated with clinical outcomes.

RESULTS

Of the 128 patients included in the study, 101 were positive for ALK and 27 for ROS1 alterations. Blood samples (N = 405) were collected from 29 patients naïve for treatment with tyrosine kinase inhibitors (TKI) or from 375 patients under treatment, including 105 samples collected at disease progression (PD). Sensitivity was 67% (n = 18 of 27) for ALK/ROS1 fusion detection. Higher detection was observed for ALK fusions at TKI failure (n = 33 of 74; 46%) versus in patients with therapeutic response (n = 12 of 109; 11%). ALK-resistance mutations were detected in 22% patients (n = 16 of 74) overall; 43% of the total ALK-resistance mutations identified occurred after next-generation TKI therapy. ALK G1202R was the most common mutation detected (n = 7 of 16). Heterogeneity of resistance was observed. ROS1 G2032R resistance was detected in 30% (n = 3 of 10). The absence of circulating tumor DNA mutations at TKI failure was associated with prolonged median overall survival (105.7 months). Complex ALK-resistance mutations correlated with poor overall survival (median, 26.9 months v NR for single mutation; P = .003) and progression-free survival to subsequent therapy (median 1.7 v 6.3 months; P = .003).

CONCLUSION

Next-generation, targeted, amplicon-based sequencing for liquid biopsy specimen profiling provides clinically relevant detection of ALK/ROS1 fusions in TKI-naïve patients and allows for the identification of resistance mutations in patients treated with TKIs. Liquid biopsy specimens from patients treated with TKIs may affect clinical outcomes and capture heterogeneity of TKI resistance, supporting their role in selecting sequential therapy.

Safety issues with the ALK inhibitors in the treatment of NSCLC: A systematic review

INTRODUCTION

Oral tyrosine kinase inhibitors targeting the chromosomal rearrangements of the anaplastic lymphoma kinase gene (ALK) in non-small cell lung cancer (NSCLC) were associated with superior clinical outcome. Tyrosine Kinase inhibitors (TKIs) are known to have peculiar toxicity profile, hence, increasing awareness to the safety profile of ALK inhibitors is essential.

METHODS

A comprehensive systematic review of literature has been conducted to include prospective trials that used the ALK inhibitors Crizotinib, Ceritinib, Alectinib, Brigatinib and Lorlatinib in patients with advanced NSCLC and have available efficacy and toxicity results.

RESULTS

A total of 14 studies including 2793 patients were considered eligible for our review and included two phase IB, seven phase II and five phase III studies. The most common adverse events (AEs) observed with ALK inhibitors were gastrointestinal (GI) toxicities as nausea (up to 83%), vomiting (up to 67%) and diarrhea (up to 86%), elevation of liver enzymes occurred in up to 60% and fatigue (up to 43%). There were differences in the toxicity patterns between the different ALK inhibitors with more GI and hepatic toxicities with Ceritinib, more visual disorders with Crizotinib, more dysgeusia with crizotinib and Alectinib and possibly more respiratory complications with Brigatinib. Most of the AEs were low grade and treatment-related deaths were associated with ALK inhibitors in 0-1% of patients.

CONCLUSION

Most of adverse effects of ALKi can be managed efficiently via dose modifications or interruptions. Timely identification of each ALKi pattern of toxicity can prevent treatment-related morbidity and mortality in this palliative setting.

Acquired resistance in oncogene-addicted non-small-cell lung cancer

The advance of tyrosine kinase inhibitors has profoundly changed the therapeutic algorithm of non-small-cell lung cancer in molecularly selected patients. However, benefit from these agents is often transient and usually most patients progress within 12 months from treatment. Novel and more potent and selective tyrosine kinase inhibitors have been developed to overcome acquired resistance; however, these agents are once again associated with only temporary benefit and patients frequently develop secondary resistance, a heterogeneous phenomenon that involves different molecular mechanisms simultaneously. The aim of our paper is to provide a comprehensive overview of the mechanisms of acquired resistance in oncogene-addicted non-small-cell lung cancer, focusing on the two most studied target, EGFR mutations and ALK translocation, and reviewing the main challenges in clinical practice.

Exosomes from Irradiated Nonsmall Cell Lung Cancer Cells Reduced Sensitivity of Recipient Cells to Anaplastic Lymphoma Kinase Inhibitors

Exosomes, released from various cell types, serve as vehicles of intercellular communication. Rearranged anaplastic lymphoma kinase (ALK) has been detected in exosomes released from cancer cells in ALK-positive nonsmall cell lung cancer (NSCLC), however, the functional consequence of ALK in exosomes has not been studied. This study aims to address whether exosomal ALK release is affected by stress, and whether exosomal ALK can modulate survival of recipient cells in vitro and in vivo. Exosomes, isolated from ALK-containing H3122 cells with (Exo-Apo) or without (Exo-Ctrl) irradiation treatment, were transferred to recipient H3122 cells in vitro or mouse xenograft in vivo. Western blot, flow cytometry, MTT, and xenograft were employed to respectively assess activation of the ALK pathway, apoptosis, cell viability, and tumor growth. Exo-Apo contained much higher levels of phosphorylated ALK (p-ALK) than that of Exo-Ctrl, and it activated AKT, STAT3, and the ERK pathway in recipient H3122 cells. ALK-specific inhibitors, including Crizotinib, Ceritinib, and TAE684, exhibited less effects on H3122 cells preincubated with Exo-Apo than on those treated with Exo-Ctrl in either inhibition of cell viability or promotion of apoptosis. Moreover, in an H3122 xenograft model, the Exo-Apo treatment resulted in a greater tumor growth and less sensitivity to Ceritinib than the Exo-Ctrl treatment. The ALK protein cargo in exosomes could be a key element to drive tumor growth and compromise therapeutic efficacy of ALK inhibitors for ALK-positive NSCLC.

EML4-ALK fusion variant V3 is a high-risk feature conferring accelerated metastatic spread, early treatment failure and worse overall survival in ALK+ non-small cell lung cancer

In order to identify anaplastic lymphoma kinase-driven non-small cell lung cancer (ALK⁺ NSCLC) patients with a worse outcome, who might require alternative therapeutic approaches, we retrospectively analyzed all stage IV cases treated at our institutions with one of the main echinoderm microtubule-associated protein-like 4 (EML4)-ALK fusion variants V1, V2 and V3 as detected by next-generation sequencing or reverse transcription-polymerase chain reaction (n = 67). Progression under tyrosine kinase inhibitor (TKI) treatment was evaluated both according to Response Evaluation Criteria in Solid Tumors (RECIST) and by the need to change systemic therapy. EML4-ALK fusion variants V1, V2 and V3 were found in 39%, 10% and 51% of cases, respectively. Patients with V3-driven tumors had more metastatic sites at diagnosis than cases with the V1 and V2 variants (mean 3.3 vs. 1.9 and 1.6, p = 0.005), which suggests increased disease aggressiveness. Furthermore, V3-positive status was associated with earlier failure after treatment with first and second-generation ALK TKI (median progression-free survival [PFS] by RECIST in the first line 7.3 vs. 39.3 months, p = 0.01), platinum-based combination chemotherapy (median PFS 5.4 vs. 15.2 months for the first line, p = 0.008) and cerebral radiotherapy (median brain PFS 6.1 months vs. not reached for cerebral radiotherapy during first-line treatment, p = 0.028), and with inferior overall survival (39.8 vs. 59.6 months in median, p = 0.017). Thus, EML4-ALK fusion variant V3 is a high-risk feature for ALK⁺ NSCLC. Determination of V3 status should be considered as part of the initial workup for this entity in order to select patients for more aggressive surveillance and treatment strategies.

Targeting ALK: Precision Medicine Takes on Drug Resistance

Anaplastic lymphoma kinase (ALK) is a validated molecular target in several ALK-rearranged malignancies, including non-small cell lung cancer. However, the clinical benefit of targeting ALK using tyrosine kinase inhibitors (TKI) is almost universally limited by the emergence of drug resistance. Diverse mechanisms of resistance to ALK TKIs have now been discovered, and these basic mechanisms are informing the development of novel therapeutic strategies to overcome resistance in the clinic. In this review, we summarize the current successes and challenges of targeting ALK.

SIGNIFICANCE

Effective long-term treatment of ALK-rearranged cancers requires a mechanistic understanding of resistance to ALK TKIs so that rational therapies can be selected to combat resistance. This review underscores the importance of serial biopsies in capturing the dynamic therapeutic vulnerabilities within a patient's tumor and offers a perspective into the complexity of on-target and off-target ALK TKI resistance mechanisms. Therapeutic strategies that can successfully overcome, and potentially prevent, these resistance mechanisms will have the greatest impact on patient outcome. Cancer Discov; 7(2); 137-55. ©2017 AACR.

STAT3-targeted treatment with silibinin overcomes the acquired resistance to crizotinib in ALK-rearranged lung cancer

The signal transducer and activator of transcription 3 (STAT3) has been suggested to play a prominent role in mediating non-small-cell lung cancer (NSCLC) resistance to some tyrosine kinase inhibitor (TKI)-mediated therapies. Using a model of anaplastic lymphoma kinase gene (ALK)-translocated NSCLC with acquired resistance to the ALK TKI crizotinib, but lacking amplifications or mutations in the kinase domain of ALK, we herein present evidence that STAT3 activation is a novel mechanism of crizotinib resistance that involves the upregulation of immune escape and epithelial to mesenchymal transition (EMT) signaling pathways. Taking advantage of the flavonolignan silibinin as a naturally occurring STAT3-targeted pharmacological inhibitor, we confirmed that STAT3 activation protects ALK-translocated NSCLC from crizotinib. Accordingly, silibinin-induced inhibition of STAT3 worked synergistically with crizotinib to reverse acquired resistance and restore sensitivity in crizotinib-resistant cells. Moreover, silibinin treatment significantly inhibited the upregulation of the immune checkpoint regulator PD-L1 and also EMT regulators (e.g., SLUG, VIM, CD44) in crizotinib-refractory cells. These findings provide a valuable strategy to potentially improve the efficacy of ALK inhibition by cotreatment with silibinin-based therapeutics, which merit clinical investigation for ALK TKI-resistant NSCLC patients.