Drug resistance in anaplastic lymphoma kinase-rearranged lung cancer

Iruplinalkib (WX-0593) Versus Crizotinib in ALK TKI-Naive Locally Advanced or Metastatic ALK-Positive NSCLC: Interim Analysis of a Randomized, Open-Label, Phase 3 Study (INSPIRE)

INTRODUCTION

Iruplinalkib (WX-0593) is a new-generation, potent ALK tyrosine kinase inhibitor (TKI) that has been found to have systemic and central nervous system (CNS) efficacy in ALK-positive NSCLC. We compared the efficacy and safety of iruplinalkib with crizotinib in patients with ALK TKI-naive, locally advanced or metastatic ALK-positive NSCLC.

METHODS

In this open-label, randomized, multicenter, phase 3 study, patients with ALK-positive NSCLC were randomly assigned to receive iruplinalkib 180 mg once daily (7-d run-in at 60 mg once daily) or crizotinib 250 mg twice daily. The primary end point was progression-free survival (PFS) assessed by Independent Review Committee (IRC) per Response Evaluation Criteria in Solid Tumors version 1.1. Secondary end points included PFS by investigator, objective response rate (ORR), time to response, duration of response, intracranial ORR and time to CNS progression by IRC and investigator, overall survival, and safety. An interim analysis was planned after approximately 70% (134 events) of all 192 expected PFS events assessed by IRC were observed. Efficacy was analyzed in the intention-to-treat population. Safety was assessed in the safety population, which included all randomized patients who received at least one dose of the study drugs. This study is registered with Center for Drug Evaluation of China National Medical Products Administration (CTR20191231) and Clinicaltrials.gov (NCT04632758).

RESULTS

From September 4, 2019, to December 2, 2020, a total of 292 patients were randomized and treated; 143 with iruplinalkib and 149 with crizotinib. At this interim analysis (145 events), the median follow-up time was 26.7 months (range: 3.7-37.7) in the iruplinalkib group and 25.9 months (range: 0.5-35.9) in the crizotinib group. The PFS assessed by IRC was significantly longer among patients in the iruplinalkib group (median PFS, 27.7 mo [95% confidence interval (CI): 26.3-not estimable] versus 14.6 mo [95% CI: 11.1-16.5] in the crizotinib group; hazard ratio, 0.34 [98.02% CI: 0.23-0.52], p < 0.0001). The ORR assessed by IRC was 93.0% (95% CI: 87.5-96.6) in the iruplinalkib group and 89.3% (95% CI: 83.1-93.7) in the crizotinib group. The intracranial ORR was 90.9% (10 of 11, 95% CI: 58.7-99.8) in the iruplinalkib group and 60.0% (nine of 15, 95% CI: 32.3-83.7) in the crizotinib group for patients with measurable baseline CNS metastases. Incidence of grade 3 or 4 treatment-related adverse events was 51.7% in the iruplinalkib group and 49.7% in the crizotinib group.

CONCLUSIONS

Iruplinalkib was found to have significantly improved PFS and improved intracranial antitumor activity versus crizotinib. Iruplinalkib may be a new treatment option for patients with advanced ALK-positive and ALK TKI-naive NSCLC.

FUNDING

This study was funded by Qilu Pharmaceutical Co., Ltd., Jinan, People's Republic of China, and partly supported by the National Science and Technology Major Project for Key New Drug Development (2017ZX09304015).

ALK-rearranged and EGFR wild-type lung adenocarcinoma transformed to small cell lung cancer: a case report

Background

Cases of ALK-rearranged EGFR wild-type lung adenocarcinoma (LUAD) transforming into small cell lung cancer (SCLC) are rarely reported, and diagnosis is often delayed. The emergence of this transformation phenomenon is often regarded as a consequence of acquired resistance mechanisms.

Case presentation

A 47-year-old male diagnosed with poorly differentiated adenocarcinoma of the right middle lung (pT2N2M0, stage IIIA) achieved a 46-month progression-free survival (PFS) following surgery and adjuvant chemotherapy. During routine follow-up, tumor recurrence and metastasis was detected. Genetic testing revealed ALK rearrangement and wild-type EGFR, prompting treatment with ALK-TKIs. In May 2023, abdominal CT scans showed significant progression of liver metastases and abnormal elevation of the tumor marker NSE. Immunohistochemical results from percutaneous liver biopsy indicated metastatic SCLC.

Results

After resistance to ALK-TKIs and transformation to SCLC, the patient received chemotherapy combined with immunotherapy for SCLC, but the patient's disease progressed rapidly. Currently, the patient is being treated with albumin-bound paclitaxel in combination with oral erlotinib and remains stable.

Conclusion

Histological transformation emerges as a compelling mechanism of resistance to ALK-TKIs, necessitating the utmost urgency for repeat biopsies in patients displaying disease progression after resistance. These biopsies are pivotal in enabling the tailor-made adaptation of treatment regimens to effectively counteract the assorted mechanisms of acquired resistance, thus optimizing patient outcomes in the battle against ALK-driven malignancies.

LTK mutations responsible for resistance to lorlatinib in non-small cell lung cancer harboring CLIP1-LTK fusion

The CLIP1-LTK fusion was recently discovered as a novel oncogenic driver in non-small cell lung cancer (NSCLC). Lorlatinib, a third-generation ALK inhibitor, exhibited a dramatic clinical response in a NSCLC patient harboring CLIP1-LTK fusion. However, it is expected that acquired resistance will inevitably develop, particularly by LTK mutations, as observed in NSCLC induced by oncogenic tyrosine kinases treated with corresponding tyrosine kinase inhibitors (TKIs). In this study, we evaluate eight LTK mutations corresponding to ALK mutations that lead to on-target resistance to lorlatinib. All LTK mutations show resistance to lorlatinib with the L650F mutation being the highest. In vitro and in vivo analyses demonstrate that gilteritinib can overcome the L650F-mediated resistance to lorlatinib. In silico analysis suggests that introduction of the L650F mutation may attenuate lorlatinib-LTK binding. Our study provides preclinical evaluations of potential on-target resistance mutations to lorlatinib, and a novel strategy to overcome the resistance.

Recent advances in molecular targeted therapy of lung cancer: Possible application in translation medicine

Lung cancer is one of the leading causes of death among all cancer deaths. This cancer is classified into two different histological subtypes: non-small cell lung cancer (NSCLC), which is the most common subtype, and small cell lung cancer (SCLC), which is the most aggressive subtype. Understanding the molecular characteristics of lung cancer has expanded our knowledge of the cellular origins and molecular pathways affected by each of these subtypes and has contributed to the development of new therapies. Traditional treatments for lung cancer include surgery, chemotherapy, and radiotherapy. Advances in understanding the nature and specificity of lung cancer have led to the development of immunotherapy, which is the newest and most specialized treatment in the treatment of lung cancer. Each of these treatments has advantages and disadvantages and causes side effects. Today, combination therapy for lung cancer reduces side effects and increases the speed of recovery. Despite the significant progress that has been made in the treatment of lung cancer in the last decade, further research into new drugs and combination therapies is needed to extend the clinical benefits and improve outcomes in lung cancer. In this review article, we discussed common lung cancer treatments and their combinations from the most advanced to the newest.

Advances in protein kinase drug discovery through targeting gatekeeper mutations

INTRODUCTION

Acquired resistance caused by gatekeeper mutations has become a major challenge for approved kinase inhibitors used in the clinic. Consequently, the development of new-generation inhibitors or degraders to overcome clinical resistance has become an important research focus for the field.

AREAS COVERED

This review summarizes the common gatekeeper mutations in druggable kinases and the constantly evolving inhibitors or degraders designed to overcome single or double mutations of gatekeeper residues. Furthermore, the authors provide their perspectives on the medicinal chemistry strategies for addressing clinical resistance with gatekeeper mutations.

EXPERT OPINION

The authors suggest optimizing kinase inhibitors to interact effectively with gatekeeper residues, altering the binding mode or binding pocket to avoid steric clashes, improving binding affinity with the target, utilizing protein degraders, and developing combination therapy. These approaches have the potential to be effective in overcoming resistance due to gatekeeper residues.

Recent advances in the development of dual ALK/ROS1 inhibitors for non-small cell lung cancer therapy

As a member of the insulin-receptor superfamily, ALK plays an important role in regulating the growth, proliferation, and survival of cells. ROS1 is highly homologous with ALK, and can also regulate normal physiological activities of cells. The overexpression of both is closely related to the development and metastasis of tumors. Therefore, ALK and ROS1 may serve as important therapeutic targets in non-small cell lung cancer (NSCLC). Clinically, many ALK inhibitors have shown powerful therapeutic efficacy in ALK and ROS1-positive NSCLC patients. However, after some time, patients inevitably develop drug resistance, leading to treatment failure. There are no significant drug breakthroughs in solving the problem of drug-resistant mutations. In this review, we summarize the chemical structural features of several novel dual ALK/ROS1 inhibitors, their inhibitory effect on ALK and ROS1 kinases, and future treatment strategies for patients with ALK and ROS1 inhibitor-resistant mutations.

Drugging Hijacked Kinase Pathways in Pediatric Oncology: Opportunities and Current Scenario

Childhood cancer is considered rare, corresponding to ~3% of all malignant neoplasms in the human population. The World Health Organization (WHO) reports a universal occurrence of more than 15 cases per 100,000 inhabitants around the globe, and despite improvements in diagnosis, treatment and supportive care, one child dies of cancer every 3 min. Consequently, more efficient, selective and affordable therapeutics are still needed in order to improve outcomes and avoid long-term sequelae. Alterations in kinases' functionality is a trademark of cancer and the concept of exploiting them as drug targets has burgeoned in academia and in the pharmaceutical industry of the 21st century. Consequently, an increasing plethora of inhibitors has emerged. In the present study, the expression patterns of a selected group of kinases (including tyrosine receptors, members of the PI3K/AKT/mTOR and MAPK pathways, coordinators of cell cycle progression, and chromosome segregation) and their correlation with clinical outcomes in pediatric solid tumors were accessed through the R2: Genomics Analysis and Visualization Platform and by a thorough search of published literature. To further illustrate the importance of kinase dysregulation in the pathophysiology of pediatric cancer, we analyzed the vulnerability of different cancer cell lines against their inhibition through the Cancer Dependency Map portal, and performed a search for kinase-targeted compounds with approval and clinical applicability through the CanSAR knowledgebase. Finally, we provide a detailed literature review of a considerable set of small molecules that mitigate kinase activity under experimental testing and clinical trials for the treatment of pediatric tumors, while discuss critical challenges that must be overcome before translation into clinical options, including the absence of compounds designed specifically for childhood tumors which often show differential mutational burdens, intrinsic and acquired resistance, lack of selectivity and adverse effects on a growing organism.

MET Amplification as a Resistance Driver to TKI Therapies in Lung Cancer: Clinical Challenges and Opportunities

Targeted therapy has emerged as an important pillar for the standard of care in oncogene-driven non-small cell lung cancer (NSCLC), which significantly improved outcomes of patients whose tumors harbor oncogenic driver mutations. However, tumors eventually develop resistance to targeted drugs, and mechanisms of resistance can be diverse. MET amplification has been proven to be a driver of resistance to tyrosine kinase inhibitor (TKI)-treated advanced NSCLC with its activation of EGFR, ALK, RET, and ROS-1 alterations. The combined therapy of MET-TKIs and EGFR-TKIs has shown outstanding clinical efficacy in EGFR-mutated NSCLC with secondary MET amplification-mediated resistance in a series of clinical trials. In this review, we aimed to clarify the underlying mechanisms of MET amplification-mediated resistance to tyrosine kinase inhibitors, discuss the ways and challenges in the detection and diagnosis of MET amplifications in patients with metastatic NSCLC, and summarize the recently published clinical data as well as ongoing trials of new combination strategies to overcome MET amplification-mediated TKI 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.

Fibroblast growth factor receptor 3 overexpression mediates ALK inhibitor resistance in ALK-rearranged non-small cell lung cancer

The rearrangement of anaplastic lymphoma kinase (ALK) occurs in 3%‐5% of patients with non–small cell lung cancer (NSCLC) and confers sensitivity to ALK–tyrosine kinase inhibitors (TKIs). For the treatment of patients with ALK‐rearranged NSCLC, various additional ALK‐TKIs have been developed. Ceritinib is a second‐generation ALK‐TKI and has shown great efficacy in the treatment of patients with both newly diagnosed and crizotinib (a first‐generation ALK‐TKI)‐refractory ALK‐rearranged NSCLC. However, tumors can also develop ceritinib resistance. This may result from secondary ALK mutations, but other mechanisms responsible for this have not been fully elucidated. In this study, we explored the mechanisms of ceritinib resistance by establishing ceritinib‐resistant, echinoderm microtubule‐associated protein‐like 4 (EML4)‐ALK–positive H3122 cells and ceritinib‐resistant patient‐derived cells. We identified a mechanism of ceritinib resistance induced by bypass signals that is mediated by the overexpression and activation of fibroblast growth factor receptor 3 (FGFR3). FGFR3 knockdown by small hairpin RNA or treatment with FGFR inhibitors was found to resensitize the resistant cells to ceritinib in vitro and in vivo. FGFR ligands from either human serum or fetal bovine serum were able to activate FGFR3 and induce ceritinib resistance. A detailed analysis of ceritinib‐resistant patient‐derived specimens confirmed that tyrosine‐protein kinase Met (cMET) amplification induces ceritinib resistance. Amplified cMET counteractivated EGFR and/or Her3 and induced ceritinib resistance. These results reveal multiple ceritinib resistance mechanisms and suggest that ceritinib resistance might be overcome by identifying precise resistance mechanisms.

HER3 activation contributes toward the emergence of ALK inhibitor-tolerant cells in ALK-rearranged lung cancer with mesenchymal features

Anaplastic lymphoma kinase-tyrosine kinase inhibitors (ALK-TKIs) have shown dramatic efficacy in patients with ALK-rearranged lung cancer; however, complete response in these patients is rare. Here, we investigated the molecular mechanisms underlying the emergence and maintenance of drug-tolerant cells in ALK-rearranged lung cancer. Cell based-assays demonstrated that HER3 activation and mesenchymal-to-epithelial transition, mediated through ZEB1 proteins, help maintain cell survival and induce the emergence of ALK-TKI-tolerant cells. Compared with ALK-TKIs alone, cotreatment with pan-HER inhibitor afatinib and ALK-TKIs prevented tumor regrowth, leading to the eradication of tumors in ALK-rearranged tumors with mesenchymal features. Moreover, pre-treatment vimentin expression in clinical specimens obtained from patients with ALK-rearranged lung cancer was associated with poor ALK-TKI treatment outcomes. These results demonstrated that HER3 activation plays a pivotal role in the emergence of ALK-TKI-tolerant cells. Furthermore, the inhibition of HER3 signals combined with ALK-TKIs dramatically improves treatment outcomes for ALK-rearranged lung cancer with mesenchymal features.

Clinical outcome, long-term survival and tolerability of sequential therapy of first-line crizotinib followed by alectinib in advanced ALK+NSCLC: A multicenter retrospective analysis in China

BACKGROUND

There is limited data on the clinical outcome, long-term survival and tolerability of sequential therapy of first-line crizotinib followed by alectinib in a real-world setting for Chinese patients with advanced ALK+ NSCLC.

METHODS

The medical records of patients who received sequential therapy with first-line crizotinib followed by alectinib (no intermittent systemic therapy was allowed between the two ALK-TKIs) were collected from six centers in China. Combined time treatment to failure (C-TTF) was defined as the period from the start of crizotinib to the complete discontinuation of alectinib due to any cause.

RESULTS

A total of 61 patients were included in our study. Fifty-two patients were switched to alectinib due to disease progression, seven as a result of toxicity, and two due to patient preference. At the time of data cutoff, alectinib treatment was discontinued in 31 patients on account of disease progression while severe adverse events resulted in cessation of alectinib in another two patients. Rebiopsy was conducted in 21 patients following disease progression on alectinib in whom ALK secondary mutation was found in 13 patients. Patients with ALK secondary mutation demonstrated better PFS during treatment with subsequent ALK-TKIs compared with those without (10.4 vs. 3.1 m, p = 0.0018, HR = 0.08). With a median follow-up of 34.3 months, C-TTF was 39.2 months and estimated 5-year OS was 68.6% in the overall population.

CONCLUSION

Sequential therapy with first-line crizotinib followed by alectinib demonstrated long-term benefits. Different efficacy in subsequent ALK-TKI between patients with or without ALK secondary mutation further emphasized the importance of rebiopsy to guide targeted therapy more precisely.

Comparative efficacy and safety of first-line treatments for advanced non-small cell lung cancer with ALK-rearranged: a meta-analysis of clinical trials

Background

Whereas there are many pharmacological interventions prescribed for patients with advanced anaplastic lymphoma kinase (ALK)- rearranged non-small cell lung cancer (NSCLC), comparative data between novel generation ALK-tyrosine kinase inhibitors (TKIs) remain scant. Here, we indirectly compared the efficacy and safety of first-line systemic therapeutic options used for the treatment of ALK-rearranged NSCLC.

Methods

We included all phase 2 and 3 randomised controlled trials (RCTs) comparing any two or three treatment options. Eligible studies reported at least one of the following outcomes: progression free survival (PFS), overall survival (OS), objective response rate (ORR), or adverse events of grade 3 or higher (Grade ≥ 3 AEs). Subgroup analysis was conducted according to central nervous system (CNS) metastases.

Results

A total of 9 RCTs consisting of 2484 patients with 8 treatment options were included in the systematic review. Our analysis showed that alectinib (300 mg and 600 mg), brigatinib, lorlatinib and ensartinib yielded the most favorable PFS. Whereas there was no significant OS or ORR difference among the ALK-TKIs. According to Bayesian ranking profiles, lorlatinib, alectinib 600 mg and alectinib 300 mg had the best PFS (63.7%), OS (35.9%) and ORR (37%), respectively. On the other hand, ceritinib showed the highest rate of severe adverse events (60%).

Conclusion

Our analysis indicated that alectinib and lorlatinib might be associated with the best therapeutic efficacy in first-line treatment for major population of advanced NSCLC patients with ALK-rearrangement. However, since there is little comparative evidence on the treatment options, there is need for relative trials to fully determine the best treatment options as well as the rapidly evolving treatment landscape.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08977-0.

High Tumor Mutation Burden and DNA Repair Gene Mutations are Associated with Primary Resistance to Crizotinib in ALK-Rearranged Lung Cancer

Background

About 20% of patients with ALK-rearranged non-small cell lung cancer (NSCLC) develop acquired resistance to tyrosine kinase inhibitor (TKI) during the first 6 months. This study aimed to examine the molecular mechanisms of early TKI resistance and prognosis in ALK-rearranged NSCLC.

Methods

Ten patients with ALK-rearranged NSCLC were included: five who developed rapid resistance to crizotinib (progression-free survival (PFS) ≤3 months) and five who exhibited a good response to crizotinib (PFS ≥36 months). The tumor specimens were subjected to whole-exome sequencing (WES). The validation cohort included 19 patients with ALK-rearranged NSCLC who received crizotinib; targeted sequencing of 43 selected genes was performed. The effect of the TP53 G245S mutation on crizotinib sensitivity was tested in H3122 cells.

Results

Mutations in DNA repair-associated genes were identified in primary resistance to crizotinib. Patients with a poor response to crizotinib harbored a greater burden of somatic mutations than those with a good response [median somatic mutations, 136 (range, 72-180) vs 31 (range, 10-48)]. Compared with the patients carrying wild-type TP53 or TP53 exon 3 deletion, 29 patients with TP53 G245S mutation showed a shorter survival time (P < 0.05), with a median PFS of 3 (95% CI: 1.9-4.1) months and a median overall survival of 7 (95% CI: 3.4-10.5) months. TP53 mutation promoted the proliferation of EML4-ALK-rearranged H3122 cells by approximately 3 folds (P < 0.001). H3122 cells with TP53 mutant were more sensitive to crizotinib compared with control cells.

Conclusion

A higher mutation burden and mutations in DNA repair gene, including TP53, were potentially associated with primary resistance to crizotinib in ALK-rearranged NSCLC. An immune-checkpoint inhibition strategy could be examined, which might overcome primary resistance to crizotinib in ALK-rearranged NSCLC.

A narrative review of tumor heterogeneity and challenges to tumor drug therapy

Objective

To accurately evaluate tumor heterogeneity, make multidimensional diagnosis according to the causes and phenotypes of tumor heterogeneity, and assist in the individualized treatment of tumors.

Background

Tumor heterogeneity is one of the most essential characteristics of malignant tumors. In tumor recurrence, development, and evolution, tumor heterogeneity can lead to the formation of different cell groups with other molecular characteristics. Tumor heterogeneity can be characterized by the uneven distribution of tumor cell subsets of other genes between and within the disease site (spatial heterogeneity) or the time change of cancer cell molecular composition (temporal heterogeneity). The discovery of tumor targeting drugs has dramatically promoted tumor therapy. However, the existence of heterogeneity seriously affects the effect of tumor treatment and the prognosis of patients.

Methods

The literature discussing tumor heterogeneity and its resistance to tumor therapy was broadly searched to analyze tumor heterogeneity as well as the challenges and solutions for gene detection and tumor drug therapy.

Conclusions

Tumor heterogeneity is affected by many factors consist of internal cell factors and cell microenvironment. Tumor heterogeneity greatly hinders effective and individualized tumor treatment. Understanding the fickle of tumors in multiple dimensions and flexibly using a variety of detection methods to capture the changes of tumors can help to improve the design of diagnosis and treatment plans for cancer and benefit millions of patients.

The mechanisms of resistance to second- and third-generation ALK inhibitors and strategies to overcome such resistance

INTRODUCTION

Anaplastic lymphoma kinase (ALK) inhibitors are widely known to contribute to the long-term survival of ALK-rearranged non-small cell lung cancer (NSCLC) patients. Based on clinical trial data, treatment with second- or third-generation ALK inhibitors can be initiated after crizotinib therapy without analyzing resistance mechanisms, and some randomized trials have recently shown the superiority of second- or third-generation ALK inhibitors over crizotinib as the initial treatment; however, the optimal treatment for patients who relapse while on second- or third-generation ALK inhibitors is not well-defined.

AREAS COVERED

This review provides an overview of the mechanisms of resistance to second- or third-generation ALK inhibitors that have been identified in both clinical and pre-clinical settings, and introduces strategies for overcoming resistance and discusses ongoing clinical trials.

EXPERT OPINION

The comprehensive elucidation of both ALK-dependent and ALK-independent resistance mechanisms is necessary to improve the prognosis of patients with ALK-rearranged NSCLC. Liquid biopsy to clarify these mechanisms of resistance might play an important role in the near future.

Efficacy and Resistance of Afatinib in Chinese Non-Small Cell Lung Cancer Patients With HER2 Alterations: A Multicenter Retrospective Study

Background

Non-small cell lung cancer (NSCLC) patients with HER2 mutations and amplification may benefit from HER2-targeted therapy, including afatinib. However, the data regarding the clinical activity of afatinib in Chinese patients with NSCLC harboring HER2 alterations are limited.

Patients and methods

We retrospectively included metastatic NSCLC patients harboring HER2 alterations who treated with afatinib. The clinical outcomes included overall response rate (ORR), progression-free survival (PFS) and overall survival (OS). The genomic profiling data after progression on afatinib were analyzed.

Results

We included 54 patients harboring HER2 mutations and 12 patients harboring HER2 amplification. The ORR was 24% (95% CI, 16–36%), the median PFS was 3.3 months (95% CI, 2.2–4.4), and the median OS was 13.9 months (95% CI, 11.4–16.5). Patients with HER2 exon 20 mutations had numerically worse ORR (17% vs 42%), shorter PFS (2.6 vs 5.8 months, HR, 2.5; 95% CI, 1.2–5.5; P = 0.015) and OS (12.9 vs 33.3 months, HR, 4.4; 95% CI, 1.3–14.8; P = 0.009) than patients with other mutations. For HER2-amplified patients, the ORR was 33% (95% CI, 14–61%), the median PFS was 3.3 months (95% CI, 2.6–4.0), and the median OS was 13.4 months (95% CI, 0–27.6). The most frequently mutated genes in afatinib-resistant patients were TP53 (44%) and EGFR (33%). Three afatinib-resistant patients harbored secondary HER2 alterations.

Conclusions

Our results suggest that afatinib has a promising anti-tumor activity in patients with NSCLC harboring HER2 alterations. To our knowledge, this is the largest retrospective study about the clinical activity of afatinib in NSCLC patients with HER2 alterations.

Head to head evaluation of second generation ALK inhibitors brigatinib and alectinib as first-line treatment for ALK+ NSCLC using an in silico systems biology-based approach

Around 3-7% of patients with non-small cell lung cancer (NSCLC), which represent 85% of diagnosed lung cancers, have a rearrangement in the ALK gene that produces an abnormal activity of the ALK protein cell signaling pathway. The developed ALK tyrosine kinase inhibitors (TKIs), such as crizotinib, ceritinib, alectinib, brigatinib and lorlatinb present good performance treating ALK+ NSCLC, although all patients invariably develop resistance due to ALK secondary mutations or bypass mechanisms. In the present study, we compare the potential differences between brigatinib and alectinib's mechanisms of action as first-line treatment for ALK+ NSCLC in a systems biology-based in silico setting. Therapeutic performance mapping system (TPMS) technology was used to characterize the mechanisms of action of brigatinib and alectinib and the impact of potential resistances and drug interferences with concomitant treatments. The analyses indicate that brigatinib and alectinib affect cell growth, apoptosis and immune evasion through ALK inhibition. However, brigatinib seems to achieve a more diverse downstream effect due to a broader cancer-related kinase target spectrum. Brigatinib also shows a robust effect over invasiveness and central nervous system metastasis-related mechanisms, whereas alectinib seems to have a greater impact on the immune evasion mechanism. Based on this in silico head to head study, we conclude that brigatinib shows a predicted efficacy similar to alectinib and could be a good candidate in a first-line setting against ALK+ NSCLC. Future investigation involving clinical studies will be needed to confirm these findings. These in silico systems biology-based models could be applied for exploring other unanswered questions.

Whole-exome mutational landscape of neuroendocrine carcinomas of the gallbladder

Neuroendocrine carcinoma (NEC) of the gallbladder (GB-NEC) is a rare but extremely malignant subtype of gallbladder cancer (GBC). The genetic and molecular signatures of GB-NEC are poorly understood; thus, molecular targeting is currently unavailable. In the present study, we applied whole-exome sequencing (WES) technology to detect gene mutations and predicted somatic single-nucleotide variants (SNVs) in 15 cases of GB-NEC and 22 cases of general GBC. In 15 GB-NECs, the C > T mutation was predominant among the 6 types of SNVs. TP53 showed the highest mutation frequency (73%, 11/15). Compared with neuroendocrine carcinomas of other organs, significantly mutated genes (SMGs) in GB-NECs were more similar to those in pulmonary large-cell neuroendocrine carcinomas (LCNECs), with driver roles for TP53 and RB1. In the COSMIC database of cancer-related genes, 211 genes were mutated. Strikingly, RB1 (4/15, 27%) and NAB2 (3/15, 20%) mutations were found specifically in GB-NECs; in contrast, mutations in 29 genes, including ERBB2 and ERBB3, were identified exclusively in GBC. Mutations in RB1 and NAB2 were significantly related to downregulation of the RB1 and NAB2 proteins, respectively, according to immunohistochemical (IHC) data (p values = 0.0453 and 0.0303). Clinically actionable genes indicated 23 mutated genes, including ALK, BRCA1, and BRCA2. In addition, potential somatic SNVs predicted by ISOWN and SomVarIUS constituted 6 primary COSMIC mutation signatures (1, 3, 30, 6, 7, and 13) in GB-NEC. Genes carrying somatic SNVs were enriched mainly in oncogenic signaling pathways involving the Notch, WNT, Hippo, and RTK-RAS pathways. In summary, we have systematically identified the mutation landscape of GB-NEC, and these findings may provide mechanistic insights into the specific pathogenesis of this deadly disease.

Crizotinib Resistance Mediated by Autophagy Is Higher in the Stem-Like Cell Subset in ALK-Positive Anaplastic Large Cell Lymphoma, and This Effect Is MYC-Dependent

Previously it was shown that autophagy contributes to crizotinib resistance in ALK-positive anaplastic large cell lymphoma (ALK + ALCL). We asked if autophagy is equally important in two distinct subsets of ALK + ALCL, namely Reporter Unresponsive (RU) and Reporter Responsive (RR), of which RR cells display stem-like properties. Autophagic flux was assessed with a fluorescence tagged LC3 reporter and immunoblots to detect endogenous LC3 alongside chloroquine, an autophagy inhibitor. The stem-like RR cells displayed significantly higher autophagic response upon crizotinib treatment. Their exaggerated autophagic response is cytoprotective against crizotinib, as inhibition of autophagy using chloroquine or shRNA against BECN1 or ATG7 led to a decrease in their viability. In contrast, autophagy inhibition in RU resulted in minimal changes. Since the differential protein expression of MYC is a regulator of the RU/RR dichotomy and is higher in RR cells, we asked if MYC regulates the autophagy-mediated cytoprotective effect. Inhibition of MYC in RR cells using shRNA significantly blunted crizotinib-induced autophagic response and effectively suppressed this cytoprotective effect. In conclusion, stem-like RR cells respond with rapid and intense autophagic flux which manifests with crizotinib resistance. For the first time, we have highlighted the direct role of MYC in regulating autophagy and its associated chemoresistance phenotype in ALK + ALCL stem-like cells.

The efficacy of lorlatinib in a lung adenocarcinoma patient with a novel ALK G1202L mutation: a case report

Acquired mutations in anaplastic lymphoma kinase (ALK) gene have been implicated as the major resistance mechanism to ALK inhibitors; however, information on the treatment options after acquiring novel ALK secondary mutations is limited. Herein, we report the efficacy of lorlatinib upon the detection of a novel ALK G1202L after progression on brigatinib. Our patient was a 30-year-old man with ALK-rearranged advanced lung adenocarcinoma. He had a partial clinical response to crizotinib lasting 11 months. Brigatinib was then administered for 12.8 months with stable disease as the best response. Sequencing at progression revealed the retention of EML4-ALK fusion and the emergence of a novel ALK G1202L mutation. With no standard treatment available, lorlatinib was administered, which achieved disease control for 9 months. Our report reveals the efficacy of lorlatinib in targeting ALK G1202L and can serve as an option for the clinical management of patients with ALK-rearranged lung adenocarcinoma after acquiring G1202L-mediated resistance from prior ALK inhibitor therapy. Furthermore, we also demonstrate the sequential use of crizotinib, brigatinib, and lorlatinib in a patient with advanced ALK-rearranged lung adenocarcinoma with an overall progression-free survival of 33.3 months for the sequential ALK inhibitor regimens. His overall survival was 41.5 months inclusive of all regimens.

Genomic characterization of a PPP1CB-ALK fusion with fusion gene amplification in a congenital glioblastoma

ALK (Anaplastic lymphoma kinase) fusion proteins are oncogenic and have been seen in various tumors. PPP1CB-ALK fusions are rare but have been reported in a few patients with low- or high-grade gliomas. However, little is known regarding the mechanism of fusion formation and genomic break points of this fusion. We performed genomic characterization of a PPP1CB-ALK fusion with fusion gene amplification in a congenital glioblastoma. The PPP1CB-ALK consists of exons 1-5 of PPP1CB and exons 20-29 of ALK. The genomic translocation breakpoints were determined by real-time quantitative PCR (RT-qPCR) and Sanger sequencing of genomic DNA. Next generation sequencing, RT-qPCR and fluorescence in situ hybridization analyses demonstrated PPP1CB-ALK amplification. Copy number analyses of genes between PPP1CB and ALK using RT-qPCR suggest that the PPP1CB-ALK is likely the result of local chromothripsis followed by episomal amplification. Transcriptome sequencing demonstrated high-level SOX2 expression and predicted WNT/β-catenin pathway activation, suggesting possible therapeutic approaches.

Novel Resistance Mechanisms Including L1196Q, P1094H, and R1248_D1249 Insertion in Three Patients With NSCLC After ALK Tyrosine Kinase Inhibitor Treatment

OBJECTIVES

The purposes of this study are to clarify the details of the ALK tyrosine kinase inhibitor (TKI) resistance mechanism in rebiopsy cases and to predict novel resistance gene alterations using molecular dynamics simulation.

METHODS

A total of 21 patients with ALK-positive NSCLC who underwent a rebiopsy after ALK TKI failure were included in this analysis. ALK fluorescence in situ hybridization and reverse transcription polymerase chain reaction were performed with paired initial and rebiopsy tumor specimens.

RESULTS

Nine patients had no known ALK resistance mechanisms. Four had ALK amplification. L1196M, I1171N, and G1269A, mutations that are known to indicate resistance to ALK TKIs, were detected in one patient each. Small cell carcinoma and sarcomatoid transition were found in one case each. L1196Q, P1094H, and exon 24 76-base pair insertion were detected after the second-generation ALK TKIs.

CONCLUSIONS

The combination of a genetic analysis and a computational simulation model may make a prediction of resistance mechanisms for overcoming ALK TKI resistance, and the construction of a genomic and simulation fused database is important for the development of personalized medicine in this field.

[Pharmacology and Clinical Evaluation of Ensartinib Hydrochloride Capsule]

肺癌是全世界发病率和致死率最高的恶性肿瘤，其中非小细胞肺癌（non-small cell lung cancer, NSCLC）约占肺癌的85%。间变性淋巴瘤激酶（anaplastic lymphoma kinase, ALK）重排阳性的NSCLC仅占全部NSCLC的5%，但预后较差，因此积极的治疗非常迫切。盐酸恩沙替尼胶囊（ensartinib hydrochloride capsule，X-396，商品名贝美纳TM）是第二代ALK抑制剂，对ALK的抑制活性和肺癌中枢神经系统转移的有效性较克唑替尼更强，并且可抑制多个克唑替尼耐药突变位点，临床拟用于治疗克唑替尼耐药的ALK阳性NSCLC。文中对盐酸恩沙替尼胶囊在国内外开展的Ⅰ期-Ⅲ期临床试验进行了总结，并对其药理作用、药代动力学和药效学、临床疗效和安全性评价进行了综述。

Making NSCLC Crystal Clear: How Kinase Structures Revolutionized Lung Cancer Treatment

The parallel advances of different scientific fields provide a contemporary scenario where collaboration is not a differential, but actually a requirement. In this context, crystallography has had a major contribution on the medical sciences, providing a “face” for targets of diseases that previously were known solely by name or sequence. Worldwide, cancer still leads the number of annual deaths, with 9.6 million associated deaths, with a major contribution from lung cancer and its 1.7 million deaths. Since the relationship between cancer and kinases was unraveled, these proteins have been extensively explored and became associated with drugs that later attained blockbuster status. Crystallographic structures of kinases related to lung cancer and their developed and marketed drugs provided insight on their conformation in the absence or presence of small molecules. Notwithstanding, these structures were also of service once the initially highly successful drugs started to lose their effectiveness in the emergence of mutations. This review focuses on a subclassification of lung cancer, non-small cell lung cancer (NSCLC), and major oncogenic driver mutations in kinases, and how crystallographic structures can be used, not only to provide awareness of the function and inhibition of these mutations, but also how these structures can be used in further computational studies aiming at addressing these novel mutations in the field of personalized medicine.

Clinical Impact of the Epithelial-Mesenchymal Transition in Lung Cancer as a Biomarker Assisting in Therapeutic Decisions

Lung cancer is one of the most common solid cancers and represents the leading cause of cancer death worldwide. Over the last decade, research on the epithelial-mesenchymal transition (EMT) in lung cancer has gained increasing attention. Here, we review clinical and histological features of non-small-cell lung cancer associated with EMT. We then aimed to establish potential clinical implications of EMT in current therapeutic options, including surgery, radiation, targeted therapy against oncogenic drivers, and immunotherapy.

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.

HDAC inhibition synergizes with ALK inhibitors to overcome resistance in a novel ALK mutated lung adenocarcinoma model

OBJECTIVES

Somatic chromosomal rearrangements resulting in ALK fusion oncogenes are observed in 3-7 % of lung adenocarcinomas. ALK tyrosine kinase inhibitors (ALKi) induce initially response, however, various resistance mechanisms limit their efficacy. Novel therapeutic approaches are of utmost importance to tailor these targeted therapies.

MATERIALS AND METHODS

A synchronous ALK-rearranged and mutated lung cancer cell line pair was established from malignant pleural effusion (PF240-PE) and carcinosis (PF240-PC) at time of ALKi resistance. Immunohistochemistry, FISH and sequencing were performed in pre- and post-treatment tumors and in both cell lines. Differentiation markers were measured by immunoblot. Viability was tested following treatment with ALKi and/or a pan-HDAC inhibitor. Additionally, a novel treatment-naïve ALK-rearranged cell line served as control. In vivo tumorigenicity was evaluated in subcutaneous xenografts.

RESULTS

Two distinct resistance mutations were identified in different carcinosis tissues at time of resistance, the previously described resistance mutation L1152R and the hitherto uncharacterized E1161K. Strikingly, PF240-PC cells carried E1161K and PF240-PE cells harbored L1152R. Immunohistochemistry and immunoblot identified epithelial-to-mesenchymal transition markers upregulated following ALKi resistance development both in carcinosis tissues and cell lines. While both lines grew as xenografts, they differed in morphology, migration, in vivo growth and sensitivity to ALKi in vitro. Strikingly, the combination of ALKi with SAHA yielded strong synergism.

CONCLUSION

Using a patient-derived ALKi resistant lung cancer model we demonstrated the synergism of HDAC and ALK inhibition. Furthermore, our findings provide strong evidence for intratumoral heterogeneity under targeted therapy and highlight the importance of site-specific mutational analysis.

Anaplastic lymphoma kinase inhibitors: an updated patent review (2014-2018)

Introduction: Anaplastic lymphoma kinase (ALK), a receptor tyrosine kinase, has been discovered in several cancers, including anaplastic large-cell lymphoma, non-small cell lung cancer, and inflammatory myofibroblastic tumors. The deregulation of ALK activities, such as translocation and point mutation, results in human carcinogenesis. The use of ALK inhibitors in clinical cancer treatment has been shown to be efficacious, and the issue of resistance to ALK inhibitors has been reported. Consequently, the development of a new generation of ALK inhibitors is necessary.Areas covered: This paper provides a comprehensive review of the patent literature from 2014 to 2018 including small molecule ALK inhibitors and their use as anticancer agents. The approved and developing ALK inhibitors are described.Expert commentary: The available three generations of ALK inhibitors have shown a good anticancer effect in ALK-positive non-small cell lung cancer. An urgent issue in this field is ALK resistance development. The development of new ALK inhibitors through structure modification of currently available ALK inhibitors is proceeding, such as the synthesis of macrocyclic compounds. This article arranges the ALK inhibitors that have published in the patent in recent years. It may help in the investigation of a new generation of ALK inhibitors, which can overcome the resistance issue and development of novel drug candidates in the future.

MAPK Pathway Alterations Correlate with Poor Survival and Drive Resistance to Therapy in Patients with Lung Cancers Driven by ROS1 Fusions

PURPOSE

ROS1 tyrosine kinase inhibitors (TKI) provide significant benefit in lung adenocarcinoma patients with ROS1 fusions. However, as observed with all targeted therapies, resistance arises. Detecting mechanisms of acquired resistance (AR) is crucial to finding novel therapies and improve patient outcomes.

EXPERIMENTAL DESIGN

ROS1 fusions were expressed in HBEC and NIH-3T3 cells either by cDNA overexpression (CD74/ROS1, SLC34A2/ROS1) or CRISPR-Cas9-mediated genomic engineering (EZR/ROS1). We reviewed targeted large-panel sequencing data (using the MSK-IMPACT assay) patients treated with ROS1 TKIs, and genetic alterations hypothesized to confer AR were modeled in these cell lines.

RESULTS

Eight of the 75 patients with a ROS1 fusion had a concurrent MAPK pathway alteration and this correlated with shorter overall survival. In addition, the induction of ROS1 fusions stimulated activation of MEK/ERK signaling with minimal effects on AKT signaling, suggesting the importance of the MAPK pathway in driving ROS1 fusion-positive cancers. Of 8 patients, 2 patients harbored novel in-frame deletions in MEK1 (MEK1delE41_L54) and MEKK1 (MEKK1delH907_C916) that were acquired after ROS1 TKIs, and 2 patients harbored NF1 loss-of-function mutations. Expression of MEK1del or MEKK1del, and knockdown of NF1 in ROS1 fusion-positive cells activated MEK/ERK signaling and conferred resistance to ROS1 TKIs. Combined targeting of ROS1 and MEK inhibited growth of cells expressing both ROS1 fusion and MEK1del.

CONCLUSIONS

We demonstrate that downstream activation of the MAPK pathway can mediate of innate acquired resistance to ROS1 TKIs and that patients harboring ROS1 fusion and concurrent downstream MAPK pathway alterations have worse survival. Our findings suggest a treatment strategy to target both aberrations.

Osimertinib Overcomes Alectinib Resistance Caused by Amphiregulin in a Leptomeningeal Carcinomatosis Model of ALK-Rearranged Lung Cancer

INTRODUCTION

Leptomeningeal carcinomatosis (LMC) occurs frequently in anaplastic lymphoma kinase (ALK)-rearranged NSCLC and develops acquired resistance to ALK tyrosine kinase inhibitors (ALK TKIs). This study aimed to clarify the resistance mechanism to alectinib, a second-generation ALK TKI, in LMC and test a novel therapeutic strategy.

METHODS

We induced alectinib resistance in an LMC mouse model with ALK-rearranged NSCLC cell line, A925LPE3, by continuous oral alectinib treatment, established A925L/AR cells. Resistance mechanisms were analyzed using several assays, including Western blot and receptor tyrosine kinase array. We also measured amphiregulin (AREG) concentrations in cerebrospinal fluid from patients with ALK-rearranged NSCLC with alectinib-refractory LMC by enzyme-linked immunosorbent assay.

RESULTS

A925L/AR cells were moderately resistant to various ALK TKIs, such as alectinib, crizotinib, ceritinib, and lorlatinib, compared with parental cells in vitro. A925L/AR cells acquired the resistance by EGFR activation resulting from AREG overexpression caused by decreased expression of microRNA-449a. EGFR TKIs and anti-EGFR antibody resensitized A925L/AR cells to alectinib in vitro. In the LMC model with A925L/AR cells, combined treatment with alectinib and EGFR TKIs, such as erlotinib and osimertinib, successfully controlled progression of LMC. Mass spectrometry imaging showed accumulation of the EGFR TKIs in the tumor lesions. Moreover, notably higher AREG levels were detected in cerebrospinal fluid of patients with alectinib-resistant ALK-rearranged NSCLC with LMC (n = 4), compared with patients with EGFR-mutated NSCLC with EGFR TKI-resistant LMC (n = 30), or patients without LMC (n = 24).

CONCLUSIONS

These findings indicate the potential of novel therapies targeting both ALK and EGFR for the treatment of ALK TKI-resistant LMC in ALK-rearranged NSCLC.

The emergence of drug resistance to targeted cancer therapies: Clinical evidence

For many decades classical anti-tumor therapies included chemotherapy, radiation and surgery; however, in the last two decades, following the identification of the genomic drivers and main hallmarks of cancer, the introduction of therapies that target specific tumor-promoting oncogenic or non-oncogenic pathways, has revolutionized cancer therapeutics. Despite the significant progress in cancer therapy, clinical oncologists are often facing the primary impediment of anticancer drug resistance, as many cancer patients display either intrinsic chemoresistance from the very beginning of the therapy or after initial responses and upon repeated drug treatment cycles, acquired drug resistance develops and thus relapse emerges, resulting in increased mortality. Our attempts to understand the molecular basis underlying these drug resistance phenotypes in pre-clinical models and patient specimens revealed the extreme plasticity and adaptive pathways employed by tumor cells, being under sustained stress and extensive genomic/proteomic instability due to the applied therapeutic regimens. Subsequent efforts have yielded more effective inhibitors and combinatorial approaches (e.g. the use of specific pharmacologic inhibitors with immunotherapy) that exhibit synergistic effects against tumor cells, hence enhancing therapeutic indices. Furthermore, new advanced methodologies that allow for the early detection of genetic/epigenetic alterations that lead to drug chemoresistance and prospective validation of biomarkers which identify patients that will benefit from certain drug classes, have started to improve the clinical outcome. This review discusses emerging principles of drug resistance to cancer therapies targeting a wide array of oncogenic kinases, along with hedgehog pathway and the proteasome and apoptotic inducers, as well as epigenetic and metabolic modulators. We further discuss mechanisms of resistance to monoclonal antibodies, immunomodulators and immune checkpoint inhibitors, potential biomarkers of drug response/drug resistance, along with possible new therapeutic avenues for the clinicians to combat devastating drug resistant malignancies. It is foreseen that these topics will be major areas of focused multidisciplinary translational research in the years to come.

Molecular Modeling of ALK L1198F and/or G1202R Mutations to Determine Differential Crizotinib Sensitivity

Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase that has been recognized as a therapeutic target for EML4-ALK fusion-positive nonsmall cell lung cancer (NSCLC) treatment using type I kinase inhibitors such as crizotinib to take over the ATP binding site. According to Shaw’s measurements, ALK carrying G1202R mutation shows reduced response to crizotinib (IC₅₀ = 382 nM vs. IC₅₀ = 20 nM for wild-type), whereas L1198F mutant is more responsive (IC₅₀ = 0.4 nM). Interestingly, the double mutant L1198F/G1202R maintains a similar response (IC₅₀ = 31 nM) to the wild-type. Herein we conducted molecular modeling simulations to elucidate the varied crizotinib sensitivities in three mutants carrying L1198F and/or G1202R. Both L1198 and G1202 are near the ATP pocket. Mutation G1202R causes steric hindrance that blocks crizotinib accessibility, which greatly reduces efficacy, whereas mutation L1198F enlarges the binding pocket entrance and hydrophobically interacts with crizotinib to enhance sensitivity. With respect to the double mutant L1198F/G1202R, F1198 indirectly pulls R1202 away from the binding entrance and consequently alleviates the steric obstacle introduced by R1202. These results demonstrated how the mutated residues tune the crizotinib response and may assist kinase inhibitor development especially for ALK G1202R, analogous to the ROS1 G2302R and MET G1163R mutations that are also resistant to crizotinib treatment in NSCLC.

Synthesis and structure-activity relationships of pyrazine-2-carboxamide derivatives as novel echinoderm microtubule-associated protein-like 4 (EML4)-anaplastic lymphoma kinase (ALK) inhibitors

Echinoderm microtubule-associated protein-like 4 (EML4)-anaplastic lymphoma kinase (ALK) is a valid therapeutic target for the treatment of EML4-ALK-positive non-small cell lung cancer (NSCLC). We discovered 12c as a novel and potent EML4-ALK inhibitor through structural optimization of 5a. In mice xenografted with 3T3 cells expressing EML4-ALK, oral administration of 12c demonstrated potent antitumor activity. This article describes the synthesis and biological evaluation of pyrazine-2-carboxamide derivatives along with studies of their structure-activity relationship (SAR) using computational modeling.

Effect of silkworm peptide on inducting M1 type polarization and Th1 activation via TLR2-induced MyD88-dependent pathway

The aim of this study was to explore immune activity and molecular mechanism of silkworm peptide. The cell subsets induced by silkworm peptides were detected by flow cytometry. The IFN-γ and IL-4 levels in CD4+ cells were measured by ELISA. TLR2 mRNA expression in mouse CD4+ T cells was detected by qRT-PCR. Western blot was used to detect the protein expression levels of MyD88 and p-IκB. The growth rate of Lewis lung cancer xenografts in mice of the medium-dose group was significantly reduced, and the tumor volume was significantly smaller than that of the control group on the 14th day. The relative vitality values of spleen lymphocytes in the medium-dose and high-dose groups were higher than the control group. The IFN-γ levels in the medium-dose and high-dose groups were significantly higher than the control group. The levels of IL-4 were no significant change among different groups. Compared with the control group, different doses of silkworm peptide groups could increase the levels of NO, IL-6, IL-12, and IL-1β. Compared with the control group, the protein expression levels of MyD88 and p-IκB in 10 μg/ml group and 20 μg/ml groups were significantly increased compared with the control group. Silkworm peptide could induce Th1 activation and M1 type polarization, which was dose-dependent and was relative to the effect of silkworm peptide on inhibiting tumor growth. Silkworm peptide could directly induce M1 type polarization and Th1 activation via TLR2-induced MyD88-dependent pathway in vitro.

Evolution of Small Molecule Kinase Drugs

The development of small molecule kinase drugs is a rapidly evolving field and represents one of the most important research areas within oncology. This innovation letter provides an overview and analysis of approved kinase drugs according to their WHO registration (INN) dates, primary biological targets, and selectivity and structural similarities, which are also depicted in an associated poster. It also discusses new trends in kinase drug discovery programs such as new kinase targets, novel mechanisms of action, and diverse indications.

Prospective analysis of liquid biopsies of advanced non-small cell lung cancer patients after progression to targeted therapies using GeneReader NGS platform

Background

In a significant percentage of advanced non-small cell lung cancer (NSCLC) patients, tumor tissue is unavailable or insufficient for genetic analyses at time to progression. We prospectively analyzed the appearance of genetic alterations associated with resistance in liquid biopsies of advanced NSCLC patients progressing to targeted therapies using the NGS platform.

Methods

A total of 24 NSCLC patients were included in the study, 22 progressing to tyrosine kinase inhibitors and two to other treatments. Liquid biopsies samples were obtained and analyzed using the GeneRead^TM QIAact Lung DNA UMI Panel, designed to enrich specific target regions and containing 550 variant positions in 19 selected genes frequently altered in lung cancer tumors. Previously, a retrospective validation of the panel was performed in clinical samples.

Results

Of the 21 patients progressing to tyrosine kinase inhibitors with valid results in liquid biopsy, NGS analysis identified a potential mechanism of resistance in 12 (57%). The most common were acquired mutations in ALK and EGFR, which appeared in 8/21 patients (38%), followed by amplifications in 5/21 patients (24%), and KRAS mutations in one patient (5%). Loss of the p.T790M was also identified in two patients progressing to osimertinib. Three of the 21 (14%) patients presented two or more concomitant alterations associated with resistance. Finally, an EGFR amplification was found in the only patient progressing to immunotherapy included in the study.

Conclusions

NGS analysis in liquid biopsies of patients progressing to targeted therapies using the GeneReader platform is feasible and can help the oncologist to make treatment decisions.

CT-707 Overcomes Resistance of Crizotinib through Activating PDPK1- AKT1 Pathway by Targeting FAK

BACKGROUND

Crizotinib established the position of anaplastic lymphoma kinase-tyrosine kinase inhibitors (ALK-TKI) in the treatment of non-small cell lung cancer (NSCLC) while the therapy- resistance hindered those patients from benefitting continuously from the treatment. CT-707 is an inhibitor of ALK/focal adhesion kinase (FAK) and IGFR-1. H2228CR (crizotinib resistance, CR) and H3122CR NSCLC cell lines were generated from the parental cell line H2228 (EML4-ALK, E6a/b:A20, variant 3) and H3122(EML4-ALK, E13:A20, variant 1), respectively.

METHODS

We investigated the antitumor effects CT-707 exerted against H3122CR in vitro /vivo.

RESULTS

Importantly, our study provided evidence that CT-707 overcomes resistance to crizotinib through activating PDPK1-AKT1 pathway by targeting FAK. Meanwhile, by using an in-vivo H3122CR xenograft model, we found CT-707 inhibited tumor growth significantly without obvious side effects.

CONCLUSION

These findings indicate that CT-707 may be a promising therapeutic agent against crizotinib- resistance in NSCLC.

Molecular Modeling for Structural Insights Concerning the Activation Mechanisms of F1174L and R1275Q Mutations on Anaplastic Lymphoma Kinase

Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase involved in various cancers. In its basal state, the structure of ALK is in an autoinhibitory form stabilized by its A-loop, which runs from the N-lobe to the C-lobe of the kinase. Specifically, the A-loop adopts an inhibitory pose with its proximal A-loop helix (αAL-helix) to anchor the αC-helix orientation in an inactive form in the N-lobe; the distal portion of the A-loop is packed against the C-lobe to block the peptide substrate from binding. Upon phosphorylation of the first A-loop tyrosine (Y1278), the αAL-helix unfolds; the distal A-loop detaches from the C-lobe and reveals the P+1 pocket that accommodates the residues immediately after their phosphorylation, and ALK is activated accordingly. Recently, two neuroblastoma mutants, F1174L and R1275Q, have been determined to cause ALK activation without phosphorylation on Y1278. Notably, F1174 is located on the C-terminus of the αC-helix and away from the A-loop, whereas R1275 sits on the αAL-helix. In this molecular modeling study, we investigated the structural impacts of F1174L and R1275Q that lead to the gain-of-function event. Wild-type ALK and ALK with phosphorylated Y1278 were also modeled for comparison. Our modeling suggests that the replacement of F1174 with a smaller residue, namely leucine, moves the αC-helix and αAL-helix into closer contact and further distorts the distal portion of the A-loop. In wild-type ALK, R1275 assumes the dual role of maintaining the αAL-helix–αC-helix interaction in an inactive form and securing αAL-helix conformation through the D1276–R1275 interaction. Accordingly, mutating R1275 to a glutamine reorients the αC-helix to an active form and deforms the entire A-loop. In both F1174L and R1275Q mutants, the A-loop rearranges itself to expose the P+1 pocket, and kinase activity resumes.

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.