Insights into ALK-driven cancers revealed through development of novel ALK tyrosine kinase inhibitors

Ultra-fast UPLC-MS/MS approach for estimating X-376 in human liver microsomes: Evaluation of metabolic stability via in silico software and in vitro analysis

X-376 is a novel anaplastic lymphoma kinase (ALK) inhibitor that is capable of penetrating the blood brain barrier. This makes it suitable for use in patients with ALK-positive non-small cell lung cancer (NSCLC) who have metastases in the central nervous system. This study developed a highly sensitive, fast, eco-friendly, and reliable UPLC-MS/MS approach to quantify X-376 in human liver microsomes (HLMs). This approach was used to evaluate X-376's metabolic stability in HLMs in vitro. The UPLC-MS/MS analytical technique validation followed US-FDA bio-analytical method validation guidelines. StarDrop software, containing P450 metabolic and DEREK modules, was utilized to scan X-376's chemical structure for metabolic lability and hazardous warnings. X-376 and Encorafenib (ENF as internal standard) were resoluted on the Eclipse Plus C18 column utilizing an isocratic mobile phase method. The X-376 calibration curve was linear from 1 to 3000 ng/mL. The precision and accuracy of this study's UPLC-MS/MS approach were tested for intra- and inter-day measurements. Inter-day accuracy was -1.32% to 9.36% while intra-day accuracy was -1.5% to 10.00%. The intrinsic clearance (Clint) and in vitro half-life (t1/2) of X-376 were 59.77 mL/min/kg and 13.56 min. The high extraction ratio of X-376 supports the 50 mg twice-daily dose for ALK-positive NSCLC and CNS metastases patients. In silico software suggests that simple structural changes to the piperazine ring or group substitution in drug design may improve metabolic stability and safety compared to X-376.

Navigating resistance to ALK inhibitors in the lorlatinib era: a comprehensive perspective on NSCLC

INTRODUCTION

The emergence of anaplastic lymphoma kinase (ALK) rearrangements in non-small cell lung cancer (NSCLC) has revolutionized targeted therapy. This dynamic landscape, featuring novel ALK inhibitors and combination therapies, necessitates a profound understanding of resistance mechanisms for effective treatment strategies. Recognizing two primary categories - on-target and off-target resistance - underscores the need for comprehensive assessment.

AREAS COVERED

This review delves into the intricacies of resistance to ALK inhibitors, exploring complexities in identification and management. Molecular testing, pivotal for early detection and accurate diagnosis, forms the foundation for patient stratification and resistance management. The literature search methodology involved comprehensive exploration of Pubmed and Embase. The multifaceted perspective encompasses new therapeutic horizons, ongoing clinical trials, and their clinical implications post the recent approval of lorlatinib.

EXPERT OPINION

Our expert opinion encapsulates the critical importance of understanding resistance mechanisms in the context of ALK inhibitors for shaping successful treatment approaches. With a focus on molecular testing and comprehensive assessment, this review contributes valuable insights to the evolving landscape of NSCLC therapy.

Current treatment and novel insights regarding ROS1-targeted therapy in malignant tumors

BACKGROUND

The proto-oncogene ROS1 encodes an intrinsic type I membrane protein of the tyrosine kinase/insulin receptor family. ROS1 facilitates the progression of various malignancies via self-mutations or rearrangements. Studies on ROS1-directed tyrosine kinase inhibitors have been conducted, and some have been approved by the FDA for clinical use. However, the adverse effects and mechanisms of resistance associated with ROS1 inhibitors remain unknown. In addition, next-generation ROS1 inhibitors, which have the advantage of treating central nervous system metastases and alleviating endogenous drug resistance, are still in the clinical trial stage.

METHOD

In this study, we searched relevant articles reporting the mechanism and clinical application of ROS1 in recent years; systematically reviewed the biological mechanisms, diagnostic methods, and research progress on ROS1 inhibitors; and provided perspectives for the future of ROS1-targeted therapy.

RESULTS

ROS1 is most expressed in malignant tumours. Only a few ROS1 kinase inhibitors are currently approved for use in NSCLC, the efficacy of other TKIs for NSCLC and other malignancies has not been ascertained. There is no effective standard treatment for adverse events or resistance to ROS1-targeted therapy. Next-generation TKIs appear capable of overcoming resistance and delaying central nervous system metastasis, but with a greater incidence of adverse effects.

CONCLUSIONS

Further research on next-generation TKIs regarding the localization of ROS1 and its fusion partners, binding sites for targeted drugs, and coadministration with other drugs is required. The correlation between TKIs and chemotherapy or immunotherapy in clinical practice requires further study.

Ensartinib is effective in the treatment of advanced non-small-cell lung cancer with MET amplification after multi-line ALK-TKIs resistance: a case report

Although patients with ALK-positive non-small cell lung cancer (NSCLC) are initially effective on treatment with ALK tyrosine kinase inhibitors (TKIs), resistance will inevitably develop. Of these patients, 2/3 will develop ALK-independent resistance and little is known about the mechanisms of ALK-independent resistance. In pre-clinical studies, the activation of several bypass signaling pathways has been implicated in the development of resistance, including the MET, EGFR, SRC and IGF1R pathways. Among these, the MET pathway is one of the signaling pathways that has recently been extensively studied, and activation of this pathway is one of the mechanisms of ALK-independent drug resistance. Here, we report a successful case of an advanced NSCLC patient who was resistant to treatment with ALK TKIs and developed MET amplification, who achieved 23 months of progression-free survival after post-line treatment with ensartinib.

Synthesis and clinical application of small-molecule inhibitors and PROTACs of anaplastic lymphoma kinase

Pharmacological interventions that specifically target protein products of oncogenes in tumors have surfaced as a propitious therapeutic approach. Among infrequent genetic alterations, rearrangements of the anaplastic lymphoma kinase (ALK) gene, typically involving a chromosome 2 inversion that culminates in a fusion with the echinoderm microtubule-associated protein like 4 (EML4), lead to anomalous expression and activation of ALK. The inhibition of autophosphorylation and subsequent blockade of signal transduction by ALK tyrosine kinase inhibitors (TKIs) has been observed to elicit anti-tumor effects. Currently, four generations of ALK-positive targeted drugs have been investigated, providing a promising outlook for patients. The aim of this review is to furnish a comprehensive survey of the synthesis and clinical application of prototypical small-molecule ALK inhibitors in both preclinical and clinical phases, offering guidance for further development of ALK inhibitors for cancer therapy.

LIMS-Kinase provides sensitive and generalizable label-free in vitro measurement of kinase activity using mass spectrometry

Measurements of kinase activity are important for kinase-directed drug development, analysis of inhibitor structure and function, and understanding mechanisms of drug resistance. Sensitive, accurate, and miniaturized assay methods are crucial for these investigations. Here, we describe a label-free, high-throughput mass spectrometry-based assay for studying individual kinase enzymology and drug discovery in a purified system, with a focus on validated drug targets as benchmarks. We demonstrate that this approach can be adapted to many known kinase substrates and highlight the benefits of using mass spectrometry to measure kinase activity in vitro, including increased sensitivity. We speculate that this approach to measuring kinase activity will be generally applicable across most of the kinome, enabling research on understudied kinases and kinase drug discovery.

Multifaceted Roles of ALK Family Receptors and Augmentor Ligands in Health and Disease: A Comprehensive Review

This review commemorates the 10-year anniversary of the discovery of physiological ligands Augα (Augmentor α; ALKAL2; Fam150b) and Augβ (Augmentor β; ALKAL1; Fam150a) for anaplastic lymphoma kinase (ALK) and leukocyte tyrosine kinase (LTK), previously considered orphan receptors. This manuscript provides an in-depth review of the biophysical and cellular properties of ALK family receptors and their roles in cancer, metabolism, pain, ophthalmology, pigmentation, central nervous system (CNS) function, and reproduction. ALK and LTK receptors are implicated in the development of numerous cancers, and targeted inhibition of their signaling pathways can offer therapeutic benefits. Additionally, ALK family receptors are involved in regulating body weight and metabolism, modulating pain signaling, and contributing to eye development and pigmentation. In the CNS, these receptors play a role in synapse modulation, neurogenesis, and various psychiatric pathologies. Lastly, ALK expression is linked to reproductive functions, with potential implications for patients undergoing ALK inhibitor therapy. Further research is needed to better understand the complex interactions of ALK family receptors and Aug ligands and to repurpose targeted therapy for a wide range of human diseases.

Case Report: Ensartinib for gastric epithelioid inflammatory myofibrosarcoma with STRN-ALK fusion

Epithelioid inflammatory myofibroblastic sarcoma (EIMS) is a highly aggressive malignant subtype of inflammatory myofibroblastoma (IMT) associated with poor prognosis. IMT can occur in various parts of the body, most frequently in the lungs, followed by the mesentery, omentum, retroperitoneum, and pelvis, among other areas; however, it is exceptionally rare in the stomach. Anaplastic lymphoma kinase (ALK) is a critical driver of lung cancer development and is currently the "gold standard" target for non-small cell lung cancer treatment. However, there are few reports on the use of ALK inhibitors for EIMS, necessitating further investigation. A male patient with postoperative inflammatory myofibroblastic sarcoma of the stomach received postoperative chemotherapy and had a stable outcome. However, a repeat CT scan performed 11 months later revealed disease progression. The patient later underwent immunohistochemistry testing that indicated ALK positivity, and next-generation sequencing revealed STRN-ALK fusion. Ensartinib 225 mg qd was administered as recommended, and the patient experienced only mild pruritus and no adverse effects such as rash. Eight months after CT follow-up, the patient's subseptal soft tissue nodules had decreased, and the outcome was assessed as a partial response. The findings of this case report introduce a novel strategy for treating ALK-positive EIMS that utilizes ensartinib, a drug with previously demonstrated success in the treatment of ALK-positive cancer.

Case Report: Long-term remission of malignant pleural and peritoneal effusion in a case of advanced lung adenocarcinoma treated with combined crizotinib and anlotinib therapy

Malignant pleural and peritoneal effusion are common clinical manifestations in advanced malignant tumors, associated with a poor prognosis. This article presents a case of advanced lung adenocarcinoma with ROS1 rearrangement, characterized by persistent malignant pleural and peritoneal effusion. The patient received combined therapy of Crizotinib and Anlotinib, resulting in a significant reduction and even disappearance of the malignant effusion. Exploratory use of this treatment approach improved the patient's quality of life and holds potential for extending overall survival. However, given the single case report nature, the efficacy of this regimen in treating advanced ROS1-rearranged lung adenocarcinoma should be considered as a supplementary strategy, warranting further validation through multicenter clinical data.

Targeting MET: Discovery of Small Molecule Inhibitors as Non-Small Cell Lung Cancer Therapy

MET has been considered as a promising drug target for the treatment of MET-dependent diseases, particularly non-small cell lung cancer (NSCLC). Small molecule MET inhibitors with mainly three types of binding modes (Ia/Ib, II, and III) have been developed. In this Review, we provide an overview of the structural features, activation mechanism, and dysregulation pathway of MET and summarize progress on the development and discovery strategies utilized for MET inhibitors as well as mechanisms of acquired resistance to current approved inhibitors. The insights will accelerate discovery of new generation MET inhibitors to overcome clinical acquired resistance.

Expert consensus of management of adverse drug reactions with anaplastic lymphoma kinase tyrosine kinase inhibitors

Anaplastic lymphoma kinase (ALK) rearrangements occur in ∼3%-6% of patients with advanced non-small-cell lung cancer (NSCLC). Small molecular drugs that effectively inhibit ALK gene have revolutionized the therapeutic paradigm for patients with ALK rearrangements, resulting in significant improvements in objective response rate, progression-free survival, and overall survival compared with classical platinum-based chemotherapy. Several ALK tyrosine kinase inhibitors (ALK-TKIs), including crizotinib, alectinib, ceritinib, brigatinib, ensartinib, and lorlatinib, have been recommended as standard first-line treatment for advanced NSCLC patients with ALK rearrangements. Patients with ALK rearrangements typically exhibit long-term durable responses to ALK-TKIs; therefore, the management of adverse drug reactions (ADRs) with ALK-TKIs is crucial in clinical practice to maximize clinical benefits, prevent an adverse impact on quality of life, and improve patient compliance. In general, ALK-TKIs are well tolerated. There are, however, a number of serious toxicities that may necessitate dose modification or even discontinuation of treatment and the management of ADRs with ALK-TKIs has grown in importance. The therapeutic use of this class of medications still carries some risk because there are currently no pertinent guidelines or consensus recommendations for managing ADRs caused by ALK-TKIs in China. In order to improve the clinical management of ADRs with ALK-TKIs, the Chinese Society of Clinical Oncology (CSCO) Non-small Cell Lung Cancer Professional Committee led the discussion and summary of the incidence, diagnosis and grading standards, and prevention and treatment of ADRs caused by ALK-TKIs.

New perspectives for targeting therapy in ALK-positive human cancers

Anaplastic lymphoma kinase (ALK) is a member of the insulin receptor protein-tyrosine kinase superfamily and was first discovered in anaplastic large-cell lymphoma (ALCL). ALK alterations, including fusions, over-expression and mutations, are highly associated with cancer initiation and progression. This kinase plays an important role in different cancers, from very rare to the more prevalent non-small cell lung cancers. Several ALK inhibitors have been developed and received Food and Drug Administration (FDA) approval. However, like other drugs used in targeted therapies, ALK inhibitors inevitably encounter cancer cell resistance. Therefore, monoclonal antibody screening based on extracellular domain or combination therapies may provide viable alternatives for treating ALK-positive tumors. In this review, we discuss the current understanding of wild-type ALK and fusion protein structures, the pathological functions of ALK, ALK target therapy, drug resistance and future therapeutic directions.

First case report of ensartinib in a patient with metastatic ALK rearranged lung cancer with ALK I1171N mutation: a case report

BACKGROUND

The acquired resistance to ALK tyrosine kinase inhibitors (TKIs) in ALK-rearranged NSCLC is associated with poor survival outcomes and poses distinct clinical challenges. It is essential to develop potential therapeutic strategies for overcoming resistance.

CASE PRESENTATION

Here, we first report a female lung adenocarcinoma patient with an acquired ALK resistance mutation (ALK 11171N) who was treated with ensartinib. Her symptoms significantly improved after only 20 days, and with a side effect of mild rash. Follow-up images observed no further brain metastases after 3 months.

CONCLUSIONS

This treatment may provide a new therapeutic strategy for ALK TKIs resistant patients, especially in position 1171 of ALK exon20.

Development of HPLC-MS/MS assay for quantitation of ensartinib in human plasma and its application to a pharmacokinetics study in Chinese patients

Ensartinib is a novel anaplastic lymphoma kinase (ALK) inhibitor with potent activity against a broad range of known crizotinib-resistant ALK mutations and is developed to treat patients with non-small-cell lung cancer. This study was the first to develop and validate a rapid and sensitive HPLC-MS/MS method for the determination of ensartinib in human plasma. The plasma samples were extracted using liquid extraction, and chromatographic separation was performed using a Phenomenex, Luna phenyl-hexyl column (50 × 2.0 mm, 5 μm). Electrospray ionization in positive-ion mode and multiple reaction monitoring were used to monitor ion transitions at m/z 561.3 → 257.1 (ensartinib) and 565.2 → 261.2 (internal standard: X-396-d4), respectively. The method yielded excellent linearity in the range of 0.5-500 ng/ml with the lowest quantification of 0.5 ng/ml. Both intra- and inter-run precisions (relative standard deviation %) were less than 15%, with accuracy (relative error %) between ±15%. Extraction recovery, matrix effect, selectivity, and stability were also validated and found to be satisfactory. Finally, the validated method was successfully applied in a phase I clinical study of ensartinib in Chinese subjects with advanced ALK-positive non-small-cell lung cancer.

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.

Case Report: Pathological Complete Response to Neoadjuvant Alectinib in a Patient With Resectable ALK-Positive Non-Small Cell Lung Cancer

Background: Alectinib, a highly selective inhibitor of ALK, is currently used in the first-line setting of untreated advanced ALK-positive NSCLC and in the second-line setting of crizotinib-resistant ALK-positive NSCLC. Despite promising efficacy and tolerability in the treatment of advanced ALK-positive NSCLC, the activity of alectinib as neoadjuvant therapy in resectable ALK-positive NSCLC remains to be investigated. Case presentation: Herein, we report a case of a 58-year-old female patient presented to our hospital with hemoptysis for 1 month. Contrast-enhanced computerized tomography (CT) of the chest showed an approximately 4.2 × 3.4 cm mass in the right hilum with localized obstructive pneumonia in the right lower lobe and multiple enlarged lymph nodes in the right hilum and mediastinum. Serum oncological markers results showed elevated levels of CA19-9, CEA, CA125, and CA242. Bronchoscopic biopsy of the mass showed poorly differentiated pulmonary adenocarcinoma and immunohistochemical testing results confirmed ALK positivity. Neoadjuvant alectinib was given at a dosage of 600 mg twice per day for two cycles (56 days), achieving a partial response of the disease with 90% shrinkage of the mass at the subsequent whole-body positron emission tomography. Repeat serum oncological markers results showed that only CA125 was elevated, but lower than before therapy. A bilobectomy of the right middle and lower lobes and systemic lymphadectomy under video-assisted thoracoscopic approach was successfully performed 7 days after the last dose of alectinib. Postoperative pathology showed pathological complete response (pCR). The patient experienced an uneventful postoperative course and continued to receive alectinib and did not report any specific discomfort at her 8-month follow-up. Thoracoabdominal CT at 8 months postoperatively showed no recurrence and repeated examination of serum oncological markers were negative. Conclusion: We report a case of resectable ALK-positive NSCLC treated with neoadjuvant aletinib achieving pCR. Our case highlights the feasibility of alectinib as neoadjuvant therapy for the treatment of resectable ALK-positive NSCLC. Undoubtedly, the safety and efficacy of this novel treatment modality needs to be explored in future large clinical trials.

Entrectinib, a new multi-target inhibitor for cancer therapy

Clinical practice shows that when single-target drugs treat multi-factor diseases such as tumors, cardiovascular system and endocrine system diseases, it is often difficult to achieve good therapeutic effects, and even serious adverse reactions may occur. Multi-target drugs can simultaneously regulate multiple links of disease, improve efficacy, reduce adverse reactions, and improve drug resistance. They are ideal drugs for treating complex diseases, and therefore have become the main direction of drug development. At present, some multi-target drugs have been successfully used in many major diseases. Entrectinib is an oral small molecule inhibitor that targets TRK, ROS1, and ALK. It is used to treat locally advanced or metastatic solid tumors with NTRK1/2/3, ROS1 and ALK gene fusion mutations. It can pass through the blood-brain barrier and is the only TRK inhibitor clinically proven to be effective against primary and metastatic brain diseases. In 2019, entrectinib was approved by the FDA to treat adult patients with ROS1-positive metastatic non-small cell lung cancer. Case reports showed that continuous administration of entrectinib was effective and tolerable. In this review, we give a brief introduction to TKK, ROS1 and ALK, and on this basis, we give a detailed and comprehensive introduction to the mechanism of action, pharmacokinetics, pharmacodynamics, clinical efficacy, tolerability and drug interactions of entrectinib.

P-glycoprotein Mediates Resistance to the Anaplastic Lymphoma Kinase Inhiitor Ensartinib in Cancer Cells

Ensartinib (X-396) is a promising second-generation small-molecule inhibitor of anaplastic lymphoma kinase (ALK) that was developed for the treatment of ALK-positive non-small-cell lung cancer. Preclinical and clinical trial results for ensartinib showed superior efficacy and a favorable safety profile compared to the first-generation ALK inhibitors that have been approved by the U.S. Food and Drug Administration. Although the potential mechanisms of acquired resistance to ensartinib have not been reported, the inevitable emergence of resistance to ensartinib may limit its therapeutic application in cancer. In this work, we investigated the interaction of ensartinib with P-glycoprotein (P-gp) and ABCG2, two ATP-binding cassette (ABC) multidrug efflux transporters that are commonly associated with the development of multidrug resistance in cancer cells. Our results revealed that P-gp overexpression, but not expression of ABCG2, was associated with reduced cancer cell susceptibility to ensartinib. P-gp directly decreased the intracellular accumulation of ensartinib, and consequently reduced apoptosis and cytotoxicity induced by this drug. The cytotoxicity of ensartinib could be significantly reversed by treatment with the P-gp inhibitor tariquidar. In conclusion, we report that ensartinib is a substrate of P-gp, and provide evidence that this transporter plays a role in the development of ensartinib resistance. Further investigation is needed.

Resistance profile and structural modeling of next-generation ROS1 tyrosine kinase inhibitors

ROS1 fusion proteins resulting from chromosomal rearrangements of the ROS1 gene are targetable oncogenic drivers in diverse cancers. Acquired resistance to targeted inhibitors curtails clinical benefit and response durability. Entrectinib, a NTRK/ROS1/ALK targeted tyrosine kinase inhibitor (TKI), was approved for the treatment of ROS1 fusion-positive NSCLC in 2019. In addition, lorlatinib and repotrectinib are actively being explored in the setting of treatment naïve or crizotinib-resistant ROS1 fusion driven NSCLC. Here, we employ an unbiased forward mutagenesis screen in Ba/F3 CD74-ROS1 and EZR-ROS1 cells to identify resistance liabilities to entrectinib, lorlatinib, and repotrectinib. ROS1^F2004C emerged as a recurrent entrectinib resistant mutation and ROS1^G2032R was discovered in entrectinib and lorlatinib-resistant clones. Cell-based and modeling data show that entrectinib is a dual type I/II mode inhibitor, and thus liable to both types of resistant mutations. Comprehensive profiling of all clinically relevant kinase domain mutations showed that ROS1^L2086F is broadly resistant to all type I inhibitors, but remains sensitive to type II inhibitors. ROS1^F2004C/I/V are resistant to type I inhibitors, entrectinib and crizotinib, and type II inhibitor, cabozantinib, but retain sensitivity to the type I macrocyclic inhibitors. Development of new, more selective type II ROS1 inhibitor(s) or potentially cycling type I and type II inhibitors may be one way to expand durability of ROS1 targeted agents.

[Treatment of ALK Positive Non-small Cell Lung Cancer with Alectinib: A Case Report and Literature Review]

肺癌是我国乃至全球发病率及死亡率均较高的恶性肿瘤，其中非小细胞肺癌占80%左右，间变性淋巴瘤激酶（anaplastic lymphoma kinase, ALK）基因突变的患者约占5%。ALK抑制剂阿来替尼的疗效优异，药物治疗不良反应的及时发现、及早治疗能极大地提高患者的临床获益。现报道包头市中心医院2020年4月收治的1例ALK阳性非小细胞肺癌的诊断、治疗及药物副反应处理，并文献复习。

Ensartinib vs Crizotinib for Patients With Anaplastic Lymphoma Kinase-Positive Non-Small Cell Lung Cancer: A Randomized Clinical Trial

Question

Is ensartinib superior to crizotinib for patients with advanced anaplastic lymphoma kinase (ALK)–positive non–small cell lung cancer (NSCLC) who have not been treated previously with an ALK inhibitor?

Findings

This randomized clinical phase 3 trial including 290 patients met the primary end point; the median progression-free survival was statistically significantly longer with ensartinib than with crizotinib (25.8 vs 12.7 months), and the confirmed intracranial response rate was 64% with ensartinib vs 21% with crizotinib for patients with brain metastases at baseline. Ensartinib had a favorable safety profile.

Meaning

Ensartinib represents a new first-line treatment option for patients with ALK-positive NSCLC.

Importance

Ensartinib, an oral tyrosine kinase inhibitor of anaplastic lymphoma kinase (ALK), has shown systemic and central nervous system efficacy for patients with ALK-positive non–small cell lung cancer (NSCLC).

Objective

To compare ensartinib with crizotinib among patients with advanced ALK-positive NSCLC who had not received prior treatment with an ALK inhibitor.

Design, Setting, and Participants

This open-label, multicenter, randomized, phase 3 trial conducted in 120 centers in 21 countries enrolled 290 patients between July 25, 2016, and November 12, 2018. Eligible patients were 18 years of age or older and had advanced, recurrent, or metastatic ALK-positive NSCLC.

Interventions

Patients were randomized (1:1) to ensartinib, 225 mg once daily, or crizotinib, 250 mg twice daily.

Main Outcomes and Measures

The primary end point was blinded independent review committee–assessed progression-free survival (PFS). Secondary end points included systemic and intracranial response, time to central nervous system progression, and overall survival. Efficacy was evaluated in the intent-to-treat (ITT) population as well as a prespecified modified ITT (mITT) population consisting of patients with central laboratory–confirmed ALK-positive NSCLC.

Results

A total of 290 patients (149 men [51.4%]; median age, 54 years [range, 25-90 years]) were randomized. In the ITT population, the median PFS was significantly longer with ensartinib than with crizotinib (25.8 [range, 0.03-44.0 months] vs 12.7 months [range, 0.03-38.6 months]; hazard ratio, 0.51 [95% CI, 0.35-0.72]; log-rank P < .001), with a median follow-up of 23.8 months (range, 0-44 months) for the ensartinib group and 20.2 months (range, 0-38 months) for the crizotinib group. In the mITT population, the median PFS in the ensartinib group was not reached, and the median PFS in the crizotinib group was 12.7 months (95% CI, 8.9-16.6 months; hazard ratio, 0.45; 95% CI, 0.30-0.66; log-rank P < .001). The intracranial response rate confirmed by a blinded independent review committee was 63.6% (7 of 11) with ensartinib vs 21.1% (4 of 19) with crizotinib for patients with target brain metastases at baseline. Progression-free survival for patients without brain metastases was not reached with ensartinib vs 16.6 months with crizotinib as a result of a lower central nervous system progression rate (at 12 months: 4.2% with ensartinib vs 23.9% with crizotinib; cause-specific hazard ratio, 0.32; 95% CI, 0.16-0.63; P = .001). Frequencies of treatment-related serious adverse events (ensartinib: 11 [7.7%] vs crizotinib: 9 [6.1%]), dose reductions (ensartinib: 34 of 143 [23.8%] vs crizotinib: 29 of 146 [19.9%]), or drug discontinuations (ensartinib: 13 of 143 [9.1%] vs crizotinib: 10 of 146 [6.8%]) were similar, without any new safety signals.

Conclusions and Relevance

In this randomized clinical trial, ensartinib showed superior efficacy to crizotinib in both systemic and intracranial disease. Ensartinib represents a new first-line option for patients with ALK-positive NSCLC.

Trial Registration

ClinicalTrials.gov Identifier: NCT02767804

Brigatinib vs alectinib in crizotinib-resistant advanced anaplastic lymphoma kinase-positive non-small-cell lung cancer (ALTA-3)

Crizotinib is highly efficacious and more tolerable than chemotherapy for ALK⁺ non-small-cell lung cancer (NSCLC), but its progression-free survival benefit and intracranial efficacy have limitations. Head-to-head comparisons of next-generation ALK inhibitors in patients with ALK⁺ NSCLC progressing on crizotinib will contribute toward optimizing survival. This international, Phase III, randomized, open-label study (ALTA-3) will therefore assign patients with locally advanced or metastatic ALK⁺ NSCLC progressing on crizotinib to receive either brigatinib 180 mg qd (7-day lead-in at 90 mg qd) or alectinib 600 mg twice daily. The primary end point is progression-free survival as assessed by a blinded Independent Review Committee; the key secondary end point is overall survival. Clinical trial registration number: NCT03596866 (ClinicalTrials.gov).

Pursuing Precision: Receptor Tyrosine Kinase Inhibitors for Treatment of Pediatric Solid Tumors

Receptor tyrosine kinases are critical for the growth and proliferation of many different cancers and therefore represent a potential vulnerability that can be therapeutically exploited with small molecule inhibitors. Over forty small molecule inhibitors are currently approved for the treatment of adult solid tumors. Their use has been more limited in pediatric solid tumors, although an increasing number of single-agent and combination studies are now being performed. These agents have been quite successful in certain clinical contexts, such as the treatment of pediatric tumors driven by kinase fusions or activating mutations. By contrast, only modest activity has been observed when inhibitors are used as single agents for solid tumors that do not have genetically defined alterations in the target genes. The absence of predictive biomarkers has limited the wider applicability of these drugs and much work remains to define the appropriate patient population and clinical situation in which receptor tyrosine kinase inhibitors are most beneficial. In this manuscript, we discuss these issues by highlighting past trials and identifying future strategies that may help add precision to the use of these agents for pediatric extracranial solid tumors.

Safety but Limited Efficacy of Ensartinib in ROS1-Positive NSCLC: A Single-Arm, Multicenter Phase 2 Study

INTRODUCTION

Some ALK inhibitors with good inhibition of ROS1 in preclinical studies have been reported to be possibly beneficial in ROS1-positive NSCLC. In this work, we studied the efficacy and safety of ensartinib in the treatment of patients with ROS1-positive NSCLC.

METHODS

The exploratory study was a phase 2, single-arm, multicenter design (NCT03608007). Patients with ROS1-positive NSCLC with a previous chemotherapy line number of less than or equal to 1 who received ensartinib at the dose of 225 mg once daily were enrolled. The primary end point was objective response rate evaluated by an investigator per Response Evaluation Criteria in Solid Tumors version 1.1.

RESULTS

From June 2018 to July 2019, a total of 59 patients were enrolled at 23 centers in the People's Republic of China. At the time of data cutoff, the median follow-up was 19.8 months (range: 0.8-22.5). The median objective response rate was 27.0 % (95 % confidence interval [CI]: 13.8-44.1) with 10 partial responses. Median duration of response was 4.8 months (95 % CI: 1.8-10.8). The median progression-free survival was 4.6 months (95 % CI: 4.0-6.4). The median overall survival was not estimable (95 % CI: 14.9-not estimable). Of four patients with brain metastases, intracranial disease control was reported in three (75.0 %, 95 % CI: 19.4-99.4). The most common treatment-related adverse events (TRAEs) were rash and liver enzyme abnormalities, with good prognosis after adjustment for dosage and concomitant medication. Most of the TRAEs were of grades 1 to 2, and incidence of grade greater than or equal to 3 TRAEs was 25.4 %.

CONCLUSIONS

Ensartinib had a modest efficacy in patients with ROS1-positive NSCLC with an acceptable safety profile.

ALTA-2: Phase II study of brigatinib in patients with ALK-positive, advanced non-small-cell lung cancer who progressed on alectinib or ceritinib

Anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitors (TKIs) have improved outcomes in ALK-rearranged (ALK+) non-small-cell lung cancer (NSCLC). However, almost all patients eventually develop progressive disease on first-line ALK TKIs (e.g., crizotinib, alectinib and ceritinib). Brigatinib, a second-generation ALK TKI, may show efficacy in alectinib- and ceritinib-refractory ALK+ NSCLC. We describe the rationale and design of ALTA-2, a Phase II study of brigatinib in patients with locally advanced/metastatic ALK+ NSCLC and documented progressive disease on alectinib or ceritinib. The primary end point is confirmed objective response rate per independent review committee using response evaluation criteria in solid tumors version 1.1. Secondary end points include duration of response, progression-free survival, overall survival, safety and health-related quality of life.

ROS1-dependent cancers - biology, diagnostics and therapeutics

The proto-oncogene ROS1 encodes a receptor tyrosine kinase with an unknown physiological role in humans. Somatic chromosomal fusions involving ROS1 produce chimeric oncoproteins that drive a diverse range of cancers in adult and paediatric patients. ROS1-directed tyrosine kinase inhibitors (TKIs) are therapeutically active against these cancers, although only early-generation multikinase inhibitors have been granted regulatory approval, specifically for the treatment of ROS1 fusion-positive non-small-cell lung cancers; histology-agnostic approvals have yet to be granted. Intrinsic or extrinsic mechanisms of resistance to ROS1 TKIs can emerge in patients. Potential factors that influence resistance acquisition include the subcellular localization of the particular ROS1 oncoprotein and the TKI properties such as the preferential kinase conformation engaged and the spectrum of targets beyond ROS1. Importantly, the polyclonal nature of resistance remains underexplored. Higher-affinity next-generation ROS1 TKIs developed to have improved intracranial activity and to mitigate ROS1-intrinsic resistance mechanisms have demonstrated clinical efficacy in these regards, thus highlighting the utility of sequential ROS1 TKI therapy. Selective ROS1 inhibitors have yet to be developed, and thus the specific adverse effects of ROS1 inhibition cannot be deconvoluted from the toxicity profiles of the available multikinase inhibitors. Herein, we discuss the non-malignant and malignant biology of ROS1, the diagnostic challenges that ROS1 fusions present and the strategies to target ROS1 fusion proteins in both treatment-naive and acquired-resistance settings.

Genotype Driven Therapy for Non-Small Cell Lung Cancer: Resistance, Pan Inhibitors and Immunotherapy

Eighty-five percent of patients with lung cancer present with Non-small Cell Lung Cancer (NSCLC). Targeted therapy approaches are promising treatments for lung cancer. However, despite the development of targeted therapies using Tyrosine Kinase Inhibitors (TKI) as well as monoclonal antibodies, the five-year relative survival rate for lung cancer patients is still only 18%, and patients inevitably become resistant to therapy. Mutations in Kirsten Ras Sarcoma viral homolog (KRAS) and epidermal growth factor receptor (EGFR) are the two most common genetic events in lung adenocarcinoma; they account for 25% and 20% of cases, respectively. Anaplastic Lymphoma Kinase (ALK) is a transmembrane receptor tyrosine kinase, and ALK rearrangements are responsible for 3-7% of NSCLC, predominantly of the adenocarcinoma subtype, and occur in a mutually exclusive manner with KRAS and EGFR mutations. Among drug-resistant NSCLC patients, nearly half exhibit the T790M mutation in exon 20 of EGFR. This review focuses on some basic aspects of molecules involved in NSCLC, the development of resistance to treatments in NSCLC, and advances in lung cancer therapy in the past ten years. Some recent developments such as PD-1-PD-L1 checkpoint-based immunotherapy for NSCLC are also covered.

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

Simple Summary

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

Abstract

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

Studying the Role and Molecular Mechanisms of MAP4K3 in Sorafenib Resistance of Hepatocellular Carcinoma

Sorafenib is the first FDA-approved therapeutic drug for molecular target medication on advanced-stage hepatocellular carcinoma. It is reported that sorafenib could improve the survival of progression-free patients for 4 to 6 months; however, most of the patients developed drug resistance. Thus, it is critical to reveal the biological mechanisms behind sorafenib resistance. In this study, a sorafenib-resistant model was developed by exposing HepG2 cells to sorafenib with gradient increasing concentration, and the resistance-related genes were screened by microarray. Real-time qPCR was used to validate selected gene expression of the resistance model, and lentivirus vector-mediated RNA interference was applied for specific gene knockdown. In addition, high-throughput High Celigo Select (HCS) and flow cytometry were used to measure the effect on cellular proliferation and apoptosis. As a result, our study established a sorafenib-resistant model with IC₅₀ of 9.988 μM. The Affymetrix expression profile of the sorafenib-resistant model showed 35 resistant-related genes, and 91.4% of the resistant genes showed upregulation in HepG2 resistance cells. In addition, 20 genes were knocked down to measure cell proliferation, and MAP4K3 with high proliferation inhibiting phenotype was chosen for further study. Meanwhile, the HCS results revealed that shMAP4K3 transfection could downregulate resistant cell proliferation, and the flow cytometry results showed that cell apoptosis was significantly increased in the MAP4K3 knockdown group. In summary, MAP4K3 is a novel molecular marker for improving the drug sensitivity of sorafenib treatment in hepatocellular carcinoma.

Fragment-based modification of 2,4-diarylaminopyrimidine derivatives as ALK and ROS1 dual inhibitors to overcome secondary mutants

In order to explore novel ALK and ROS1 dual inhibitors capable of overcoming crizotinib-resistant mutants, two series of 2,4-diarylaminopyrimidine derivatives were designed, synthesized and evaluated for their in vitro cytotoxic activity. In this work, we retained the 2,4-diarylaminopyrimidine scaffold and derivatize the DAAP scaffold with sulfonyl and acrylamide moieties to extend the structure-activity relationship (SAR) study. To our delight, some compounds exhibited excellent inhibitory activity with a double-digit nanomolar level in MTT assay. Four compounds were selected for enzymic assays further, the results led to the identification of a potent ALK and ROS1 dual inhibitor X-17, with IC₅₀ values of 3.7 nM, 2.3 nM, 8.9 nM and 1.9 nM against ALK, ALK^L1196M, ALK^G1202R and ROS1, respectively. Ultimately, the molecular docking studies on X-17 clearly disclosed reasonable and optimal binding interactions with ALK.

High Levels of miR-7-5p Potentiate Crizotinib-Induced Cytokilling and Autophagic Flux by Targeting RAF1 in NPM-ALK Positive Lymphoma Cells

Simple Summary

Anaplastic lymphoma kinase positive anaplastic large cell lymphomas are a pediatric disease, which still needs treatment improvement. Crizotinib was the first ALK-targeted inhibitor used in clinics, but relapses are now known to occur. Current research efforts indicate that combined therapies could represent a superior strategy to eradicate malignant cells and prevent tumor recurrence. Autophagy is a self-digestion cellular process, known to be induced upon diverse cancer therapies. Our present work demonstrates that the potentiation of the crizotinib-induced autophagy flux, through the serine/threonine kinase RAF1 downregulation, drives ALK+ ALCL cells to death. These results should encourage further investigations on the therapeutic modulation of autophagy in this particular cancer settings and other ALK-related malignancies.

Abstract

Anaplastic lymphoma kinase positive anaplastic large cell lymphomas (ALK+ ALCL) are an aggressive pediatric disease. The therapeutic options comprise chemotherapy, which is efficient in approximately 70% of patients, and targeted therapies, such as crizotinib (an ALK tyrosine kinase inhibitor (TKI)), used in refractory/relapsed cases. Research efforts have also converged toward the development of combined therapies to improve treatment. In this context, we studied whether autophagy could be modulated to improve crizotinib therapy. Autophagy is a vesicular recycling pathway, known to be associated with either cell survival or cell death depending on the cancer and therapy. We previously demonstrated that crizotinib induced cytoprotective autophagy in ALK+ lymphoma cells and that its further intensification was associated with cell death. In line with these results, we show here that combined ALK and Rapidly Accelerated Fibrosarcoma 1 (RAF1) inhibition, using pharmacological (vemurafenib) or molecular (small interfering RNA targeting RAF1 (siRAF1) or microRNA-7-5p (miR-7-5p) mimics) strategies, also triggered autophagy and potentiated the toxicity of TKI. Mechanistically, we found that this combined therapy resulted in the decrease of the inhibitory phosphorylation on Unc-51-like kinase-1 (ULK1) (a key protein in autophagy initiation), which may account for the enforced autophagy and cytokilling effect. Altogether, our results support the development of ALK and RAF1 combined inhibition as a new therapeutic approach in ALK+ ALCL.

Mass balance, metabolic disposition, and pharmacokinetics of [14C]ensartinib, a novel potent anaplastic lymphoma kinase (ALK) inhibitor, in healthy subjects following oral administration

PURPOSE

Ensartinib is a novel, potent and highly selective inhibitor of anaplastic lymphoma kinase (ALK) that has promising clinical activity and low toxicity in patients with ALK-positive non-small cell lung cancer. This study was conducted to investigate the pharmacokinetics, metabolism and excretion of ensartinib following a single 200 mg/100 μCi oral dose of radiolabeled ensartinib to healthy subjects.

METHODS

Six healthy male subjects were enrolled and administrated an oral suspension in a fasted state. Blood, urine and feces were collected. Radioactivity concentrations were measured by liquid scintillation counting and plasma concentrations of ensartinib by liquid chromatography-tandem mass spectrometry. Both techniques were applied for metabolite profiling and characterization.

RESULTS

The mean total recovery was 101.21% of the radiolabeled dose with 91.00% and 10.21% excreted in feces and urine, respectively. Unchanged ensartinib was the predominant drug-related component in urine and feces, representing 4.39% and 38.12% of the administered dose, respectively. Unchanged ensartinib and its metabolite M465 were the major circulating components, accounting for the same 27.45% of the plasma total radioactivity (AUC_0-24h pool), while other circulating metabolites were minor, accounting for less than 10%. Mean C_max, AUC_0-∞, T_1/2 and T_max values for ensartinib in plasma were 185 ng/mL, 3827 h ng/mL, 18.3 h and 3.25 h, respectively. The total radioactivity in plasma was cleared with terminal half-life of 27.2 h. Treatment with ensartinib was well tolerated, and no serious adverse events were reported.

CONCLUSION

It was well tolerated in the six healthy male subjects following a single oral administration of 200 mg/100 μCi dose of ensartinib. Besides unchanged ensartinib, metabolite of M465 was the predominant circulating drug-related component. The drug was primarily eliminated in feces.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov NCT03804541.

1-(4-((5-chloro-4-((2-(isopropylsulfonyl)phenyl)amino)pyrimidin-2-yl)amino)-3-methoxyphenyl)-3-(2-(dimethylamino)ethyl)imidazolidin-2-one (ZX-42), a novel ALK inhibitor, induces apoptosis and protective autophagy in H2228 cells

OBJECTIVES

To examine the antiproliferative effects of 1-(4-((5-chloro-4-((2-(isopropylsulfonyl)phenyl)amino)pyrimidin-2-yl)amino)-3-methoxyphenyl)-3-(2-(dimethylamino)ethyl)imidazolidin-2-one (ZX-42) on the echinoderm microtubule-associated protein-4/anaplastic lymphoma kinase fusion gene (EML4-ALK) positive lung cancer cell line H2228 and its underlying mechanism.

METHODS

The MTT assay was used to study the effect of ZX-42 on H2228 cell growth. Propidium iodide (PI) staining and Western blotting were used to investigate the cell cycle changes. ZX-42-induced cell apoptosis was determined using the Annexin V-FITC/PI (AV/PI) apoptotic assay kit, acridine orange/ethidium bromide (AO/EB) and Hoechst 33258 staining, Rhodamine 123 (Rh 123) fluorescence assay and Western blotting. ZX-42-induced reactive oxygen species (ROS) production was examined by ROS assay kit. Transmission electron microscope, monodansylcadaverine (MDC) staining and the AV/PI apoptotic assay kit were used to demonstrate the relationship between autophagy and apoptosis.

KEY FINDINGS

ZX-42 had good cell viability inhibitory effect on H2228 cells. ZX-42 dramatically inhibited ALK and its downstream pathways. ZX-42 also blocked H2228 cell cycle at G1 phase and then induced apoptosis by activating the mitochondrial pathway. Next, ZX-42 induced the production of ROS, and antioxidant N-acetylcysteine (NAC) reduced ROS production and also decreased apoptotic rates. We also found that ZX-42 induced protective autophagy in H2228 cells.

CONCLUSIONS

In summary, ZX-42 is a novel ALK inhibitor that significantly inhibits the cell viability of H2228 cells and ultimately induces apoptosis through the mitochondrial pathway, in which autophagy plays a protective role. Therefore, inhibition of autophagy might enhance the anti-cancer effect of ZX-42.

Targeted drug therapy in non-small cell lung cancer: Clinical significance and possible solutions-Part I

INTRODUCTION

Non-small cell lung cancer (NSCLC) comprises of 84% of all lung cancer cases. The treatment options for NSCLC at advanced stages are chemotherapy and radiotherapy. Chemotherapy involves conventional nonspecific chemotherapeutics, and targeted-protein/receptor-specific small molecule inhibitors. Biologically targeted therapies such as an antibody-based immunotherapy have been approved in combination with conventional therapeutics. Approved targeted chemotherapy is directed against the kinase domains of mutated cellular receptors such as epidermal growth factor receptor (EGFR), anaplastic lymphoma kinases (ALK), neurotrophic receptor kinases (NTRK) and against downstream signaling molecules such as BRAF (v-raf murine sarcoma viral oncogene homolog B1). Approved biologically targeted therapy involves the use of anti-angiogenesis antibodies and antibodies against immune checkpoints.

AREAS COVERED

The rationale for the employment of targeted therapeutics and the resistance that may develop to therapy are discussed. Novel targeted therapeutics in clinical trials are also included.

EXPERT OPINION

Molecular and histological profiling of a given tumor specimen to determine the aberrant onco-driver is a must before deciding a targeted therapeutic regimen for the patient. Periodic monitoring of the patients response to a given therapeutic regimen is also mandatory so that any semblance of resistance to therapy can be deciphered and the regimen may be accordingly altered.

[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.

N-[18F]-Fluoroacetylcrizotinib: A potentially potent and selective PET tracer for molecular imaging of non-small cell lung cancer

N-[18F]fluoroacetylcrizotinib, a fluorine-18 labeled derivative of the first FDA approved tyrosine kinase inhibitor (TKI) for the treatment of Anaplastic lymphoma kinase (ALK)-rearranged non-small cell lung cancer (NSCLC), crizotinib, was successfully synthesized for use in positron emission tomography (PET). Sequential in vitro biological evaluation of fluoracetylcrizotinib and in vivo biodistribution studies of [18F]fluoroacetylcrizotinib demonstrated that the biological activity of the parent compound remained unchanged, with potent ALK kinase inhibition and effective tumor growth inhibition. These results show that [18F]fluoroacetylcrizotinib has the potential to be a promising PET ligand for use in NSCLC imaging. The utility of PET in this context provides a non-invasive, quantifiable method to inform on the pharmacokinetics of an ALK-inhibitor such as crizotinib prior to a clinical trial, as well as during a trial in the event of acquired drug resistance.

Vulnerability of drug-resistant EML4-ALK rearranged lung cancer to transcriptional inhibition

A subset of lung adenocarcinomas is driven by the EML4-ALK translocation. Even though ALK inhibitors in the clinic lead to excellent initial responses, acquired resistance to these inhibitors due to on-target mutations or parallel pathway alterations is a major clinical challenge. Exploring these mechanisms of resistance, we found that EML4-ALK cells parental or resistant to crizotinib, ceritinib or alectinib are remarkably sensitive to inhibition of CDK7/12 with THZ1 and CDK9 with alvocidib or dinaciclib. These compounds robustly induce apoptosis through transcriptional inhibition and downregulation of anti-apoptotic genes. Importantly, alvocidib reduced tumour progression in xenograft mouse models. In summary, our study takes advantage of the transcriptional addiction hypothesis to propose a new treatment strategy for a subset of patients with acquired resistance to first-, second- and third-generation ALK inhibitors.

Immune Checkpoint Blockade in Oncogene-Driven Non-Small-Cell Lung Cancer

Patients with oncogene-driven lung cancer have limited therapeutic options after progressing on their targeted tyrosine kinase inhibitor (TKI) therapy. Given the growing role of immune checkpoint inhibitor (ICI) therapy in the treatment of lung cancer, oncogene-driven cancer has warranted further evaluation regarding ICI therapy. However, initial ICI studies have suggested that ICI monotherapy is not only lacking in efficacy, but that it may be less tolerable in oncogene-driven non-small-cell lung cancer (NSCLC). We performed a detailed review of the literature using Pubmed, and present the current and impactful findings here. Studies evaluating the use of concurrent ICI therapy and TKI therapy have also suggested increased toxicity and lack of increased activity in these patients. Larger studies have suggested that the sequence of ICI therapy and TKI, such as utilizing ICI therapy after TKI as opposed to before TKI, may play a role in reducing toxicity (hepatotoxicity, pneumonitis); however, these studies are limited in number. Novel methods of patient selection, including low tumor mutational burden, inflamed phenotyping, and  high CD8 + tumor infiltrating lymphocytes, may aid in determining ideal patients to give ICI therapy. Novel therapeutic combinations including the addition of anti-VEGF (vascular endothelial growth factor) therapy or radiotherapy show promising findings for these patients. Given the growing unmet need for therapeutic options in patients with oncogene-driven NSCLC who have failed TKI therapy, further research is warranted.

Ensartinib (X-396) Effectively Modulates Pharmacokinetic Resistance Mediated by ABCB1 and ABCG2 Drug Efflux Transporters and CYP3A4 Biotransformation Enzyme

Ensartinib (X-396) is a promising tyrosine kinase inhibitor currently undergoing advanced clinical evaluation for the treatment of non-small cell lung cancer. In this work, we investigate possible interactions of this promising drug candidate with ATP-binding cassette (ABC) drug efflux transporters and cytochrome P450 biotransformation enzymes (CYPs), which play major roles in multidrug resistance (MDR) and pharmacokinetic drug-drug interactions (DDIs). Accumulation studies showed that ensartinib is a potent inhibitor of ABCB1 and ABCG2 transporters. Additionally, incubation experiments with recombinant CYPs showed that ensartinib significantly inhibits CYP3A4 and CYP2C9. Subsequent molecular docking studies confirmed these findings. Drug combination experiments demonstrated that ensartinib synergistically potentiates the antiproliferative effects of daunorubicin, mitoxantrone, and docetaxel in ABCB1, ABCG2, and CYP3A4-overexpressing cellular models, respectively. Advantageously, ensartinib’s antitumor efficiency was not compromised by the presence of MDR-associated ABC transporters, although it acted as a substrate of ABCB1 in Madin-Darby Canine Kidney II (MDCKII) monolayer transport assays. Finally, we demonstrated that ensartinib had no significant effect on the mRNA-level expression of examined transporters and enzymes in physiological and lung tumor cellular models. In conclusion, ensartinib may perpetrate clinically relevant pharmacokinetic DDIs and modulate ABCB1-, ABCG2-, and CYP3A4-mediated MDR. The in vitro findings presented here will provide a valuable foundation for future in vivo investigations.

Clinical consequences of resistance to ALK inhibitors in non-small cell lung cancer

Introduction: ALK rearrangements are present in 2-7% of non-small cell lung cancer (NSCLC) cases, where the EML4-ALK fusion is the most frequent. Rearrangement of ALK with other fusion partners occurs only in ≈5% of NSCLC ALK-positive. These patients have benefited from ALK inhibitors, and currently, there are three generations of drugs as the standard of care. The first-generation ALK inhibitor crizotinib is approved in the front-line setting for the treatment of advanced NSCLC; unfortunately, these tumors may eventually develop resistance to this molecule. The Second-generation ALK inhibitors, ceritinib, alectinib, and brigatinib, are approved for patients recently diagnosed or in relapse. The third-generation inhibitor lorlatininb is approved for patients who have developed resistance to any ALK inhibitor.Areas covered: In this review, an unstructured search in Pubmed and SCOPUS was conducted. We summarized the mechanisms of resistance to ALK inhibitors and its consequences in the treatment-decision making in advanced or metastatic NSCLC after failure to a first-line ALK inhibitor.Expert opinion: Currently, there are a growing number of options of therapeutic agents against ALK+ NSCLC (approved and in development); however, adequate selection and sequencing of agents are crucial to deal with the tumor evolution.

Phase I metabolic profiling and unexpected reactive metabolites in human liver microsome incubations of X-376 using LC-MS/MS: bioactivation pathway elucidation and in silico toxicity studies of its metabolites

Metabolites of X-376 were characterized by LC-MS/MS. Pyridazine ring and dichloro-phenyl groups were bioactivated by novel pathways.

Monitoring Therapeutic Response and Resistance: Analysis of Circulating Tumor DNA in Patients With ALK+ Lung Cancer

INTRODUCTION

Despite initial effectiveness of ALK receptor tyrosine kinase inhibitors (TKIs) in patients with ALK+ NSCLC, therapeutic resistance will ultimately develop. Serial tracking of genetic alterations detected in circulating tumor DNA (ctDNA) can be an informative strategy to identify response and resistance. This study evaluated the utility of analyzing ctDNA as a function of response to ensartinib, a potent second-generation ALK TKI.

METHODS

Pre-treatment plasma was collected from 76 patients with ALK+ NSCLC who were ALK TKI-naive or had received prior ALK TKI, and analyzed for specific genetic alterations. Longitudinal plasma samples were analyzed from a subset (n = 11) of patients. Analysis of pre-treatment tumor biopsy specimens from 22 patients was compared with plasma.

RESULTS

Disease-associated genetic alterations were detected in 74% (56 of 76) of patients, the most common being EML4-ALK. Concordance of ALK fusion between plasma and tissue was 91% (20 of 22 blood and tissue samples). Twenty-four ALK kinase domain mutations were detected in 15 patients, all had previously received an ALK TKI; G1269A was the most prevalent (4 of 24). Patients with a detectable EML4-ALK variant 1 (V1) fusion had improved response (9 of 17 patients; 53%) to ensartinib compared to patients with EML4-ALK V3 fusion (one of seven patients; 14%). Serial changes in ALK alterations were observed during therapy.

CONCLUSIONS

Clinical utility of ctDNA was shown, both at pre-treatment by identifying a potential subgroup of ALK+ NSCLC patients who may derive more benefit from ensartinib and longitudinally by tracking resistance. Prospective application of this technology may translate to improved outcomes for NSCLC patients treated with ALK TKIs.

Efficacy, safety, and biomarker analysis of ensartinib in crizotinib-resistant, ALK-positive non-small-cell lung cancer: a multicentre, phase 2 trial

BACKGROUND

Ensartinib is a potent new-generation ALK inhibitor with high activity against a broad range of known crizotinib-resistant ALK mutations and CNS metastases. We aimed to assess the efficacy and safety of ensartinib in ALK-positive patients with non-small-cell lung cancer (NSCLC), in whom crizotinib therapy was unsuccessful. The associations between ensartinib efficacy and crizotinib-resistant mutations were also explored.

METHODS

We did a single-arm, open-label, phase 2 study at 27 centres in China. Patients were aged 18 years or older, had stage IIIb or stage IV ALK-positive NSCLC that had progressed while they were on crizotinib therapy, an Eastern Cooperative Oncology Group performance status of 2 or less, had measurable disease, and had received fewer than three previous treatments. Patients with CNS metastases were included if these metastases were asymptomatic and did not require steroid therapy. All patients received 225 mg ensartinib orally once daily on a continuous dosing schedule. The primary outcome was the proportion of patients with an objective response according to the Response Evaluation Criteria in Solid Tumors (version 1.1), as assessed by an independent review committee in all patients who received at least one dose of ensartinib with no major violations of the inclusion criteria (ie, the full analysis set). Safety was assessed in all enrolled patients who received at least one dose of ensartinib. This trial was registered with ClinicalTrials.gov, NCT03215693.

FINDINGS

Between Sept 28, 2017, and April 11, 2018, 160 patients were enrolled and had at least one dose of ensartinib (safety analysis set). Four patients had inclusion violations and were excluded from the efficacy analysis, which thus included 156 patients (full analysis set). 97 (62%) patients in the full analysis set had brain metastases. 76 (52% [95% CI 43-60]) of 147 patients in the full analysis set, with responses that could be assessed by the independent review committee, had an objective response. 28 (70% [53-83]) of 40 patients with measurable brain metastases as assessed by the independent review committee had an intracranial objective response. 145 (91%) of 160 patients had at least one treatment-related adverse event, which were mostly grade 1 or 2. The most common treatment-related adverse events were rash (89 [56%]), increased alanine aminotransferase concentrations (74 [46%]), and increased aspartate aminotransferase concentrations (65 [41%]).

INTERPRETATION

Ensartinib has activity and is well tolerated in patients with crizotinib-refractory, ALK-positive NSCLC, including those with brain metastases. The role of ensartinib in patients in whom other second-generation ALK inhibitors have been unsuccessful warrants further studies.

FUNDING

Betta Pharmaceuticals.

Drug Discovery Targeting Anaplastic Lymphoma Kinase (ALK)

As a receptor tyrosine kinase of insulin receptor (IR) subfamily, anaplastic lymphoma kinase (ALK) has been validated to play important roles in various cancers, especially anaplastic large cell lymphoma (ALCL), nonsmall cell lung cancer (NSCLC), and neuroblastomas. Currently, five small-molecule inhibitors of ALK, including Crizotinib, Ceritinib, Alectinib, Brigatinib, and Lorlatinib, have been approved by the U.S. Food and Drug Administration (FDA) against ALK-positive NSCLCs. Novel type-I¹/₂ and type-II ALK inhibitors with improved kinase selectivity and enhanced capability to combat drug resistance have also been reported. Moreover, the "proteolysis targeting chimera" (PROTAC) technique has been successfully applied in developing ALK degraders, which opened a new avenue for targeted ALK therapies. This review provides an overview of the physiological and biological functions of ALK, the discovery and development of drugs targeting ALK by focusing on their chemotypes, activity, selectivity, and resistance as well as potential therapeutic strategies to overcome drug resistance.

Novel derivatives of anaplastic lymphoma kinase inhibitors: Synthesis, radiolabeling, and preliminary biological studies of fluoroethyl analogues of crizotinib, alectinib, and ceritinib

Anaplastic lymphoma kinase (ALK), an oncogenic receptor tyrosine kinase, is a therapeutic target in various cancers, including non-small cell lung cancer. Although several ALK inhibitors, including crizotinib, ceritinib, and alectinib, are approved for cancer treatment, their long-term benefit is often limited by the cancer's acquisition of resistance owing to secondary point mutations in ALK. Importantly, some ALK inhibitors cannot cross the blood-brain barrier (BBB) and thus have little or no efficacy against brain metastases. The introduction of a lipophilic moiety, such as a fluoroethyl group may improve the drug's BBB penetration. Herein, we report the synthesis of fluoroethyl analogues of crizotinib 1, alectinib 4, and ceritinib 9, and their radiolabeling with ¹⁸F for pharmacokinetic studies. The fluoroethyl derivatives and their radioactive analogues were obtained in good yields with high purity and good molar activity. A cytotoxicity screen in ALK-expressing H2228 lung cancer cells showed that the analogues had up to nanomolar potency and the addition of the fluorinated moiety had minimal impact overall on the potency of the original drugs. Positron emission tomography in healthy mice showed that the analogues had enhanced BBB penetration, suggesting that they have therapeutic potential against central nervous system metastases.

Emerging therapies for non-small cell lung cancer

Recent advances in the field of novel anticancer agents prolong patients' survival and show a promising future. Tyrosine kinase inhibitors and immunotherapy for lung cancer are the two major areas undergoing rapid development. Although increasing novel anticancer agents were innovated, how to translate and optimize these novel agents into clinical practice remains to be explored. Besides, toxicities and availability of these drugs in specific regions should also be considered during clinical determination. Herein, we summarize emerging agents including tyrosine kinase inhibitors, checkpoint inhibitors, and other potential immunotherapy such as chimeric antigen receptor T cell for non-small cell lung cancer attempting to provide insights and perspectives of the future in anticancer treatment.