ALK Resistance Mutations and Efficacy of Lorlatinib in Advanced Anaplastic Lymphoma Kinase-Positive Non-Small-Cell Lung Cancer

Polyclonal on- and off-target resistance mutations in an EML4-ALK positive non-small cell lung cancer patient under ALK inhibition

Treatment of advanced stage anaplastic lymphoma kinase (ALK) positive non-small cell lung cancer (NSCLC) with ALK tyrosine kinase inhibitors (TKIs) has been shown to be superior to standard platinum-based chemotherapy. However, secondary progress of disease frequently occurs under ALK inhibitor treatment. The clinical impact of re-biopsies for treatment decisions beyond secondary progress is, however, still under debate. Here, we report on two novel subsequent polyclonal on- and off-target resistance mutations in a patient with ALK-fused NSCLC under ALK inhibitor treatment. A 63-year-old male patient with an advanced stage EML4-ALK fused pulmonary adenocarcinoma was initially successfully treated with the second-generation ALK inhibitor alectinib and upon progressions subsequently with brigatinib, lorlatinib and chemoimmunotherapy (CIT). Progress to alectinib was associated with a so far undescribed ALK mutation (p.A1200_G1201delinsW) which was, however, tractable by brigatinib. An off-target KRAS-mutation (p.Q61K) occurred in association with subsequent progression under second-line TKI treatment. Third-line lorlatinib showed limited efficacy but chemoimmunotherapy resulted in disappearance of the KRAS mutant clone and clinical tumor control for another eight months. In conclusion, we suggest molecular profiling of progressive tumor disease also for ALK-positive NSCLC to personalize treatment in a subgroup of ALK-positive patients.

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

TPX-0131, a Potent CNS-penetrant, Next-generation Inhibitor of Wild-type ALK and ALK-resistant Mutations

Since 2011, with the approval of crizotinib and subsequent approval of four additional targeted therapies, anaplastic lymphoma kinase (ALK) inhibitors have become important treatments for a subset of patients with lung cancer. Each generation of ALK inhibitor showed improvements in terms of central nervous system (CNS) penetration and potency against wild-type (WT) ALK, yet a key continued limitation is their susceptibility to resistance from ALK active-site mutations. The solvent front mutation (G1202R) and gatekeeper mutation (L1196M) are major resistance mechanisms to the first two generations of inhibitors while patients treated with the third-generation ALK inhibitor lorlatinib often experience progressive disease with multiple mutations on the same allele (mutations in cis, compound mutations). TPX-0131 is a compact macrocyclic molecule designed to fit within the ATP-binding boundary to inhibit ALK fusion proteins. In cellular assays, TPX-0131 was more potent than all five approved ALK inhibitors against WT ALK and many types of ALK resistance mutations, e.g., G1202R, L1196M, and compound mutations. In biochemical assays, TPX-0131 potently inhibited (IC50 <10 nmol/L) WT ALK and 26 ALK mutants (single and compound mutations). TPX-0131, but not lorlatinib, caused complete tumor regression in ALK (G1202R) and ALK compound mutation-dependent xenograft models. Following repeat oral administration of TPX-0131 to rats, brain levels of TPX-0131 were approximately 66% of those observed in plasma. Taken together, preclinical studies show that TPX-0131 is a CNS-penetrant, next-generation ALK inhibitor that has potency against WT ALK and a spectrum of acquired resistance mutations, especially the G1202R solvent front mutation and compound mutations, for which there are currently no effective therapies.

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).

Resistance profiles of anaplastic lymphoma kinase tyrosine kinase inhibitors in advanced non-small-cell lung cancer: a multicenter study using targeted next-generation sequencing

INTRODUCTION

Anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitors (TKIs) crizotinib, ceritinib, alectinib, brigatinib, and lorlatinib are approved for advanced non-small-cell lung cancer (NSCLC) with ALK rearrangement. However, the mechanisms of resistance remain largely unclear.

METHODS

This prospective multicenter study analyzed cell-free DNA (cfDNA) and/or cancer tissues of patients with NSCLC after progression on ALK TKI(s), using targeted next-generation sequencing. Patients' clinicopathologic characteristics and treatment outcomes were analyzed.

RESULTS

Overall, 88 patients were enrolled; 31 cancer tissues and 90 cfDNA samples were analyzed. Five (16%) ALK mutations (L1196M ×2, I1171T, D1203N, G1269A/F1174L) and 3 possible bypass mutations (NRAS G12V, EGFR R108K, PIK3CA E545K) were found in 32 crizotinib-resistant cancers. Four (22%) ALK mutations (G1128A, G1202R, G1269A, I1171T/E1210K) and 3 possible bypass mutations (KIT D820E, MET E1012∗, EGFR P265_C291del) were found in 18 ceritinib-resistant cancers. Four (17%) ALK mutations (G1202R ×2, W1295C, G1202R/L1196M) and 1 possible bypass mutation (EGFR P753S) were found in 24 alectinib-resistant cancers. Two (11%) ALK mutations (G1202R/G1269A ×2) and 2 possible bypass mutations (BRAF V600E, MET D1246N) were found in 18 lorlatinib-resistant cancers. In patients with simultaneous paired tissue and cfDNA samples (n = 20), mutations were identified in 9 (45%) and 6 (30%) cases, respectively; the concordance rate was 45%.

CONCLUSIONS

The mechanisms of ALK TKI resistance were heterogeneous; ALK mutations were found in less than one-third of patients. Compound ALK mutations, which may confer lorlatinib resistance, may occur in crizotinib, ceritinib, and alectinib-resistant lung cancers.

Exceptional response to the ALK and ROS1 inhibitor lorlatinib and subsequent mechanism of resistance in relapsed ALK F1174L-mutated neuroblastoma

Treatment of high-risk neuroblastoma typically incorporates multiagent chemotherapy, surgery, radiation therapy, autologous stem cell transplantation, immunotherapy, and differentiation therapy. The discovery of activating mutations in ALK receptor tyrosine kinase (ALK) in ∼8% of neuroblastomas opens the possibility of further improving outcomes for this subset of patients with the addition of ALK inhibitors. ALK inhibitors have shown efficacy in tumors such as non-small-cell lung cancer and anaplastic large cell lymphoma in which wild-type ALK overexpression is driven by translocation events. In contrast, ALK mutations driving neuroblastomas are missense mutations in the tyrosine kinase domain yielding constitutive activation and differing sensitivity to available ALK inhibitors. We describe a case of a patient with relapsed, refractory, metastatic ALK F1174L-mutated neuroblastoma who showed no response to the first-generation ALK inhibitor crizotinib but had a subsequent complete response to the ALK/ROS1 inhibitor lorlatinib. The patient's disease relapsed after 13 mo of treatment. Sequencing of cell-free DNA at the time of relapse pointed toward a potential mechanism of acquired lorlatinib resistance: amplification of CDK4 and FGFR1 and a NRAS Q61K mutation. We review the literature regarding differing sensitivity of ALK mutations found in neuroblastoma to current FDA-approved ALK inhibitors and known pathways of acquired resistance. Our report adds to the literature of important correlations between neuroblastoma ALK mutation status and clinical responsiveness to ALK inhibitors. It also highlights the importance of understanding acquired mechanisms of resistance.

ALK-positive non-small cell lung cancer; potential combination drug treatments

Advances in chromosomally rearranged ALK positive non-small cell lung cancer have been dramatic in only the last few years. Survival times have improved dramatically due to the introduction of ever more efficacious ALK inhibitors. These improvements have been due largely to improvements in blood-brain barrier penetration and the breadth of ligand binding pocket mutations against which the drugs are effective. However, the advances maybe slow as compared to the frequency of cancers with compound resistance mutations are appearing, suggesting the need to develop multiple ALK inhibitors to target different compound mutations.Another research area that promises to provide further gains is the use of drug combinations, with an ALK inhibitor combined with a drug targeting a "second driver" to overcome resistance. In this review, the range of secondary targets for ALK+ lung cancer and the potential for their clinical success are reviewed.

Advances in targeted therapy in non-small cell lung cancer with actionable mutations and leptomeningeal metastasis

WHAT IS KNOWN AND OBJECTIVE?: Leptomeningeal metastasis (LM) is a serious complication of advanced non-small cell lung cancer (NSCLC) that is diagnosed in approximately 3%-5% of patients. LM occurs more frequently in patients with NSCLC harbouring epidermal growth factor receptor (EGFR) mutations or anaplastic lymphoma kinase (ALK) rearrangements and is usually accompanied by a poor prognosis, with a median overall survival (OS) of several months if patients receive conventional treatments. However, tyrosine kinase inhibitor (TKI) therapy after LM diagnosis is an independent predictive factor for extended survival. Here, we aim to summarize the latest advances in targeted therapy for LM and provide patients with better treatment options. METHODS: By reviewing the recent progress of targeted therapy in NSCLC with LM, especially the efficacy of newer generation TKIs, we aim to provide clinicians with a reference to further optimize patient treatment plans. RESULTS AND DISCUSSION: Osimertinib was confirmed to have a several-fold higher CNS permeability than other EGFR-TKIs and was recommended as the preferred choice for patients with EGFR-positive LM whether or not they harboured the T790M mutation. Second-generation ALK-TKIs have a higher rate of intracranial response and can be positioned as front-line drugs in NSCLC with LM. However, the sequence in which ALK-TKIs are administered for effective disease control requires further evaluation. In addition, targeted therapy revealed a potential choice in patients with LM and rare mutations, such as ROS1 and BRAF. WHAT IS NEW AND CONCLUSIONS?: The development of therapeutic agents with greater CNS penetration is vital for the management of CNS metastasis from NSCLC, particularly in the EGFR-mutant and ALK-rearranged subtypes. Systemic therapy with newer generation TKIs is preferred as the initial intervention. This is because newer generation TKIs are designed to penetrate the blood-brain barrier and possess significantly higher intracranial activities. However, their further effectiveness is limited by inadequate blood-brain barrier penetration and acquired drug resistance. Further studies are needed to further understand the mechanisms underlying resistance to treatment.

Targeted therapy in advanced non-small cell lung cancer: current advances and future trends

Lung cancer remains the leading cause of cancer-related mortality in both men and women in the US and worldwide. Non-small cell lung cancer is the most common variety accounting for 84% of the cases. For a subset of patients with actionable mutations, targeted therapy continues to provide durable responses. Advances in molecular and immunohistochemical techniques have made it possible to usher lung cancer into the era of personalized medicine, with the patient getting individualized treatment based on these markers. This review summarizes the recent advances in advanced NSCLC targeted therapy, focusing on first-in-human and early phase I/II clinical trials in patients with advanced disease. We have divided our discussion into different topics based on these agents' mechanisms of action. This article is aimed to be the most current review of available and upcoming targeted NSCLC treatment options. We will also summarize the currently available phase I/II clinical trial for NSCLC patients at the end of each section.

Real-world efficacy and safety of lorlatinib in treating advanced ALK-positive non-small cell lung cancer patients

OBJECTIVE

Anaplastic lymphoma kinase (ALK) translocation is a rare driver mutation in lung cancer. This study was aimed to report on the efficacy of lorlatinib in real-world practice and to evaluate the impact of prior ALK inhibitor treatments.

METHODS

We retrospectively evaluated patients with ALK-positive non-small cell lung cancer (NSCLC) treated with lorlatinib regarding its efficacy, the impact of prior ALK inhibitor treatments and the adverse events, in particular dyslipidemia.

RESULTS

A total of 22 ALK-positive patients were analyzed. All patients had received at least one second-generation ALK inhibitor(s), while 12 patients had a history of crizotinib treatment. For lorlatinib, the objective response rate was 35.7%, and disease control rate was 64.3%. Their progression-free survival (PFS) was 6.2 months. With prior therapies, patients receiving only second-generation ALK inhibitor(s) treatment showed PFS longer than those with both crizotinib and second-generation ALK inhibitor(s) treatments (15.2 vs. 6.2 months). Moreover, patients who showed benefits from prior ALK inhibitor(s) also had a PFS longer than those who did not (6.5 vs. 3.5 months). Regarding adverse events, 94.7% of patients had dyslipidemia and 21.1% of them were in grade 3 or 4. None of these patients discontinued the treatment due to dyslipidemia. No acute complication occurred with dyslipidemia.

CONCLUSION

The real-world efficacy of lorlatinib and adverse events were similar to those reported in clinical trials. Interestingly, the history and responses of prior ALK inhibitor treatments may influence the efficacy of subsequent lorlatinib treatment.

Actionability of on-target ALK Resistance Mutations in Patients With Non-Small Cell Lung Cancer: Local Experience and Review of the Literature

INTRODUCTION

Non-small cell lung cancer (NSCLC) patients with Anaplastic Lymphoma Kinase (ALK) gene fusions respond well to ALK inhibitors but commonly develop on-target resistance mutations. The objective of this study is to collect clinical evidence for subsequent treatment with ALK inhibitors.

PATIENTS AND METHODS

Local experience with on-target ALK resistance mutations and review of the literature identified 387 patients with ALK inhibitor resistance mutations. Clinical benefit of mutation-inhibitor combinations was assessed based on reported response, progression-free survival and duration of treatment. Furthermore, this clinical evidence was compared to previously reported in vitro sensitivity of mutations to the inhibitors.

RESULTS

Of the pooled population of 387 patients in this analysis, 239 (62%) received at least 1 additional line of ALK inhibition after developing on-target resistance to ALK inhibitor therapy. Clinical benefit was reported for 177 (68%) patients, but differed for each mutation-inhibitor combination. Agreement between in vitro predicted sensitivity of 6 published models and observed clinical benefit ranged from 64% to 87%. The observed clinical evidence for highest probability of response in the context of specific on-target ALK inhibitor resistance mutations is presented.

CONCLUSION

Molecular diagnostics performed on tissue samples that are refractive to ALK inhibitor therapy can reveal new options for targeted therapy for NSCLC patients. Our comprehensive overview of clinical evidence of drug actionability of ALK on-target resistance mechanisms may serve as a practical guide to select the most optimal drug for individual patients.

An ocular lesion of unknown aetiology

Can you diagnose this patient with vision problems? https://bit.ly/3vGe5qy.

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.

Going beneath the tip of the iceberg. Identifying and understanding EML4-ALK variants and TP53 mutations to optimize treatment of ALK fusion positive (ALK+) NSCLC

Since the discovery of echinoderm microtubule-associated protein-like 4 (EML4) and anaplastic lymphoma kinase (ALK) gene fusion in non-small cell lung carcinoma (NSCLC) in 2007, more than 10 EML4-ALK variants based on the exon breakpoints in EML4 have been identified. Unlike other receptor tyrosine kinase fusion positive NSCLC such as ROS1 or RET fusion, EML4-ALK is the dominant fusion variant in ALK+ NSCLC accounting for approximately 85 % of all fusion variants in ALK+ NSCLC. Currently, eight EML4-ALK variants are generally recognized with a number (1, 2, 3a/b, 4', 5a/b, 5', 7, 8) with EML4-ALK variants 1 and 3 being the two most common variants accounting for 75-80 % of the total EML4-ALK variants. Preclinical, retrospective analyses of institutional databases, and global randomized phase 3 trials have demonstrated differential clinical response (overall response rate, progression-free survival) to ALK tyrosine kinase inhibitors (TKIs) between the "short" (v3 and v5) and "long" (v1, v2, v5', v7, and v8) EML4-ALK variants. We discuss in more details how EML4-ALK variant structure influences protein stability and response to ALK TKIs. Additionally, the most recalcitrant single solvent-front mutation ALK G1202R is more prone to develop among EML4-ALK v3 following sequential use of next-generation ALK TKIs. Furthermore, TP53 mutations being the most common genomic co-alterations in ALK+ NSCLC also contribute to the heterogeneous response to ALK TKIs. Recognizing ALK+ NSCLC is not one homogeneous disease entity but comprised of different ALK fusion variants with different underlying genomic alterations in particular TP53 mutations that modulate treatment response will provide insight into the further optimization of treatment of ALK+ NSCLC patients potentially leading to improvement in survival.

The novel FAT4 activator jujuboside A suppresses NSCLC tumorigenesis by activating HIPPO signaling and inhibiting YAP nuclear translocation

FAT atypical cadherin 4 (FAT4) has been identified as a tumor suppressor in lung cancers. However, no agent for lung cancer treatment targeting FAT4 has been used in the clinic. Jujuboside A (JUA) is a major active compound in Semen Ziziphi Spinosae. Semen Ziziphi Spinosae is a traditional Chinese herbal medicine used clinically for tumor treatment to improve patients' quality of life. However, the anti-lung cancer activity and the underlying mechanisms of JUA are not yet fully understood. Here, we demonstrated the anti-lung cancer activity of JUA in two lung cancer mice models and three non-small cell lung cancer (NSCLC) cell lines, and further illustrated its underlying mechanisms. JUA suppressed the occurrence and development of lung cancer and extended mice survival in vivo, and suppressed NSCLC cell activities through cell cycle arrest, proliferation suppression, stemness inhibition and senescence promotion. Moreover, JUA directly bound with and activated FAT4, subsequently activating FAT4-HIPPO signaling and inhibiting YAP nuclear translocation. Knockdown of FAT4 diminished JUA's effects on HIPPO signaling, YAP nuclear translocation, cell proliferation and cellular senescence. In conclusion, JUA significantly suppressed NSCLC tumorigenesis by regulating FAT4-HIPPO-YAP signaling. Our findings suggest that JUA is a novel FAT4 activator that can be developed as a promising NSCLC therapeutic agent targeting the FAT4-HIPPO-YAP pathway.

Next-generation sequencing-based identification of EGFR and NOTCH2 complementary mutations in non-small cell lung cancer

Although targeted therapy has emerged as an effective treatment strategy for non-small cell lung cancer (NSCLC), some patients cannot benefit from such therapy due to the limited number of therapeutic targets. The present study aimed to identify mutated genes associated with clinicopathological characteristics and prognosis and to screen for mutations that are not concurrent with applicable drug target sites in patients with NSCLC. Tumor tissue and blood samples were obtained from 97 patients with NSCLC. A lung cancer-specific panel of 55 genes was established and analyzed using next-generation sequencing (NGS). The results obtained from the clinical cohort were compared with the NSCLC dataset from The Cancer Genome Atlas (TCGA). Subsequently, 25 driver genes were identified by taking the intersection of the 55 lung-cancer-specific genes with three databases, namely, the Catalog of Somatic Mutations in Cancer database, the Network of Cancer Genes database and Vogelstein's list. Functional annotation and protein-protein interaction analysis were conducted on these 25 driver genes. The χ² test and logistic regression were used to evaluate the association between mutations in the 25 driver genes and the clinicopathological characteristics of 97 patients, and phosphatase and tensin homolog (PTEN) and kirsten rat sarcoma viral oncogene homolog (KRAS) were associated with stage at diagnosis and sex, respectively, while epidermal growth factor receptor (EGFR) was associated with sex, stage at diagnosis, metastasis, CEA and CYFRA21-1. Moreover, the association between the 25 driver gene mutations and overall survival were examined using Cox regression analysis. Age and Notch homolog 2 (NOTCH2) mutations were independent prognostic factors in TCGA dataset. The correlations between statistically significant mutations in EGFR, KRAS, PTEN and NOTCH2 were further examined, both in the clinical data and TCGA dataset. There was a negative correlation between EGFR and NOTCH2 mutations (correlation coefficient, −0.078; P=0.027). Thus, the present study highlights the importance of NOTCH2 mutations and might provide novel therapeutic options for patients with NSCLC who do not harbor EGFR mutations.

Precision Medicine in Oncology: A Review of Multi-Tumor Actionable Molecular Targets with an Emphasis on Non-Small Cell Lung Cancer

Precision medicine is essential for the modern care of a patient with cancer. Comprehensive molecular profiling of the tumor itself is necessary to determine the presence or absence of certain targetable abnormalities or biomarkers. In particular, lung cancer is a disease for which targetable genomic alterations will soon guide therapy in the majority of cases. In this comprehensive review of solid tumor-based biomarkers, we describe the genomic alterations for which targeted agents have been approved by the United States Food and Drug Administration (FDA). While focusing on alterations leading to approvals in a tumor-agnostic fashion (MSI-h, TMB-h, NTRK) and on those alterations with approvals in multiple malignancies (BRAF, ERBB2, RET, BRCA, PD-L1), we also describe several biomarkers or indications that are likely to lead to an approved drug in the near future (e.g., KRAS G12C, PD-L1 amplification, HER2 overexpression in colon cancer, HER2 mutations in lung cancer). Finally, we detail the current landscape of additional actionable alterations (EGFR, ALK, ROS1, MET) in lung cancer, a biomarker-rich malignancy that has greatly benefitted from the precision oncology revolution.

Liquid biopsy for therapy monitoring in early-stage non-small cell lung cancer

Liquid biopsy is now considered a valuable diagnostic tool for advanced metastatic non-small cell lung cancer (NSCLC). In NSCLC, circulating tumor DNA (ctDNA) analysis has been shown to increase the chances of identifying the presence of targetable mutations and has been adopted by many clinicians owing to its low risk. Serial monitoring of ctDNA may also help assess the treatment response or for monitoring relapse. As the presence of detectable plasma ctDNA post-surgery likely indicates residual tumor burden, studies have been performed to quantify plasma ctDNA to assess minimal residual disease (MRD) in early-stage resected NSCLC. Most data on utilizing liquid biopsy for monitoring MRD in early-stage NSCLC are from small-scale studies using ctDNA. Here, we review the recent research on liquid biopsy in NSCLC, not limited to ctDNA, and focus on novel methods such as micro RNAs (miRNA) and long non-coding (lncRNA).

Efficacy of lorlatinib in lung carcinomas carrying distinct ALK translocation variants: The results of a single-center study

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In patients with ALK-rearranged NSCLC who received lorlatinib within the compassionate use program, the objective tumor response (OR) and disease control (DC) were observed in 43% and 94% cases, respectively.

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Lorlatinib showed particularly high efficacy against brain metastases, with OR and DC for intracranial disease reaching 81% and 100%, respectively.

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Patients with V.1 and V.3 ALK translocations had similar response to the therapy.

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Complete lack of adverse events tended to correlate with poor outcome of lorlatinib treatment.

Background

Lorlatinib is a novel potent ALK inhibitor, with only a few studies reporting the results of its clinical use.

Methods

This study describes the outcomes of lorlatinib treatment for 35 non-small cell lung cancer patients with ALK rearrangements, who had 2 (n = 5), 1 (n = 26) or none (n = 4) prior tyrosine kinase inhibitors and received lorlatinib mainly within the compassionate use program.

Results

Objective tumor response (OR) and disease control (DC) were registered in 15/35 (43%) and 33/35 (94%) patients, respectively; brain metastases were particularly responsive to the treatment (OR: 22/27 (81%); DC: 27/27 (100%)). Median progression free survival (PFS) was estimated to be 21.8 months, and median overall survival (OS) approached to 70.1 months. Only 4 out of 35 patients experienced no adverse effects; two of them were the only subjects who had no clinical benefit from lorlatinib. PFS and OS in the no-adverse-events lorlatinib users were strikingly lower as compared to the remaining patients (1.1 months vs. 23.7 months and 10.5 months vs. not reached, respectively; p < 0.0001 for both comparisons). ALK translocation variants were known for 28 patients; there was no statistical difference between patients with V.1 and V.3 rearrangements with regard to the OS or PFS.

Conclusion

Use of lorlatinib results in excellent disease outcomes, however caution must be taken for patients experiencing no adverse effects from this drug.

Identification of Key Genes With Differential Correlations in Lung Adenocarcinoma

Background

With the advent of large-scale molecular profiling, an increasing number of oncogenic drivers contributing to precise medicine and reshaping classification of lung adenocarcinoma (LUAD) have been identified. However, only a minority of patients archived improved outcome under current standard therapies because of the dynamic mutational spectrum, which required expanding susceptible gene libraries. Accumulating evidence has witnessed that understanding gene regulatory networks as well as their changing processes was helpful in identifying core genes which acted as master regulators during carcinogenesis. The present study aimed at identifying key genes with differential correlations between normal and tumor status.

Methods

Weighted gene co-expression network analysis (WGCNA) was employed to build a gene interaction network using the expression profile of LUAD from The Cancer Genome Atlas (TCGA). R package DiffCorr was implemented for the identification of differential correlations between tumor and adjacent normal tissues. STRING and Cytoscape were used for the construction and visualization of biological networks.

Results

A total of 176 modules were detected in the network, among which yellow and medium orchid modules showed the most significant associations with LUAD. Then genes in these two modules were further chosen to evaluate their differential correlations. Finally, dozens of novel genes with opposite correlations including ATP13A4-AS1, HIGD1B, DAP3, and ISG20L2 were identified. Further biological and survival analyses highlighted their potential values in the diagnosis and treatment of LUAD. Moreover, real-time qPCR confirmed the expression patterns of ATP13A4-AS1, HIGD1B, DAP3, and ISG20L2 in LUAD tissues and cell lines.

Conclusion

Our study provided new insights into the gene regulatory mechanisms during transition from normal to tumor, pioneering a network-based algorithm in the application of tumor etiology.

Earlier extracranial progression and shorter survival in ALK-rearranged lung cancer with positive liquid rebiopsies

BACKGROUND

Liquid rebiopsies can detect resistance mutations to guide therapy of anaplastic lymphoma kinase-rearranged (ALK+) non-small-cell lung cancer (NSCLC) failing tyrosine kinase inhibitors (TKI). Here, we analyze how their results relate to the anatomical pattern of disease progression and patient outcome.

METHODS

Clinical, molecular, and radiologic characteristics of consecutive TKI-treated ALK+ NSCLC patients were analyzed using prospectively collected plasma samples and the 17-gene targeted AVENIO kit, which covers oncogenic drivers and all TP53 exons.

RESULTS

In 56 patients, 139 instances of radiologic changes were analyzed, of which 133 corresponded to disease progression. Circulating tumor DNA (ctDNA) alterations were identified in most instances of extracranial progression (58/94 or 62%), especially if concomitant intracranial progression was also present (89%, P<0.001), but rarely in case of isolated central nervous system (CNS) progression (8/39 or 21%, P<0.001). ctDNA detectability correlated with presence of "short" echinoderm microtubule-associated protein-like 4 (EML4)-ALK fusion variants (mainly V3, E6:A20) and/or TP53 mutations (P<0.05), and presented therapeutic opportunities in <50% of cases. Patients with extracranial progression and positive liquid biopsies had shorter survival from the start of palliative treatment (mean 52 vs. 69 months, P=0.002), regardless of previous and subsequent therapy and initial ECOG performance status. Furthermore, for patients with extracranial progression, ctDNA detectability was associated with shorter next-line progression-free survival (PFS) (3 vs. 13 months, P=0.003) if they were switched to another systemic therapy (49/86 samples), and with shorter time-to-next-treatment (TNT) (3 vs. 8 months, P=0.004) if they were continued on the same treatment due to oligoprogression (37/86). In contrast, ctDNA detectability was not associated with the outcome of patients showing CNS-only progression. In 6/6 cases with suspicion of non-neoplastic radiologic lung changes (mainly infection or pneumonitis), ctDNA results remained negative.

CONCLUSIONS

Positive blood-based liquid rebiopsies in ALK+ NSCLC characterize biologically more aggressive disease and are common with extracranial, but rare with CNS-only progression or benign radiologic changes. These results reconcile the increased detection of ALK resistance mutations with other features of the high-risk EML4-ALK V3-associated phenotype. Conversely, most oligoprogressive patients with negative liquid biopsies have a more indolent course without need for early change of systemic treatment.

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.

Aust D, B. Baretton G. Routine Molecular Pathology Diagnostics in Precision Oncology

BACKGROUND

Technical advances in the field of molecular genetics permit precise genomic characterization of malignant tumors. This has not only improved our understanding of tumor biology but also paved the way for molecularly stratified treatment strategies in routine clinical practice.

METHODS

A selective search of PubMed to identify literature on molecular pathology methods, their indications, the challenges associated with molecular findings, and future developments.

RESULTS

Tumors can be characterized with the aid of immunohistochemistry, in-situ hybridization, and sequencing of DNA or RNA. The benefits of molecularly stratified tumor treatment have been demonstrated by randomized clinical trials on numerous tumor entities, e.g., non-small-cell lung cancer, colorectal cancer, and breast cancer. Therefore, initiation of specific treatment for these entities should be preceded by molecular pathology biomarker analyses, generally carried out on tumor tissue. Randomized controlled trials and non-controlled studies show that enhanced progression-free survival ensues if the pharmacological treatment is oriented on the findings of molecular pathology diagnostics. In next-generation sequencing, numerous relevant gene sequences or even whole genes can be sequenced in parallel, dispensing with complex staged diagnostics and reducing the use of biomaterials. These new methods also complement the currently relevant predictive biomarkers by permitting the investigation of genetic alterations presently of interest in the context of clinical studies. Prior to widespread routine clinical application, however, sequencing of large gene panels or whole genomes or exomes need to be even more stringently validated.

CONCLUSION

Quality-assured molecular pathology assays are universally available for the determination of currently relevant predictive biomarkers. However, the integration of extensive genomic analyses into routine molecular pathology diagnostics represents a future challenge in precision oncology.

Future Perspectives in Detecting EGFR and ALK Gene Alterations in Liquid Biopsies of Patients with NSCLC

Non-small-cell lung cancer (NSCLC) is a major cause of death worldwide. Alterations in such genes as EGFR and ALK are considered important biomarkers in NSCLC due to the existence of targeted therapies with specific tyrosine kinase inhibitors (TKIs). However, specific resistance-related mutations can occur during TKI treatment, which often result in therapy inefficacy. Liquid biopsies arise as a reliable tool for the early detection of these types of alterations, allowing a non-invasive follow-up of the patients. Furthermore, they can be essential for cancer screening, initial diagnosis and to check surgery success. Despite the great advantages of liquid biopsies in NSCLC and the high input that next-generation sequencing (NGS) approaches can provide in this field, its use in oncology is still limited. With improvement of assay sensitivity and the establishment of clinical guidelines for liquid biopsy analysis, it is expected that they will be used in routine procedures. This review focuses on the usefulness of liquid biopsies of NSCLC patients as a means to detect alterations in EGFR and ALK genes and in disease management, highlighting the impact of NGS methods.

Overcoming Resistance to Tumor-Targeted and Immune-Targeted Therapies

Resistance to anticancer therapies includes primary resistance, usually related to lack of target dependency or presence of additional targets, and secondary resistance, mostly driven by adaptation of the cancer cell to the selection pressure of treatment. Resistance to targeted therapy is frequently acquired, driven by on-target, bypass alterations, or cellular plasticity. Resistance to immunotherapy is often primary, orchestrated by sophisticated tumor-host-microenvironment interactions, but could also occur after initial efficacy, mostly when only partial responses are obtained. Here, we provide an overview of resistance to tumor and immune-targeted therapies and discuss challenges of overcoming resistance, and current and future directions of development. SIGNIFICANCE: A better and earlier identification of cancer-resistance mechanisms could avoid the use of ineffective drugs in patients not responding to therapy and provide the rationale for the administration of personalized drug associations. A clear description of the molecular interplayers is a prerequisite to the development of novel and dedicated anticancer drugs. Finally, the implementation of such cancer molecular and immunologic explorations in prospective clinical trials could de-risk the demonstration of more effective anticancer strategies in randomized registration trials, and bring us closer to the promise of cure.

Development of an optimal protocol for molecular profiling of tumor cells in pleural effusions at single-cell level

Liquid biopsy analyzes the current status of primary tumors and their metastatic regions. We aimed to develop an optimized protocol for single-cell sequencing of floating tumor cells (FTCs) in pleural effusion as a laboratory test. FTCs were enriched using a negative selection of white blood cells by a magnetic-activated cell sorting system, and CD45-negative and cytokeratin-positive selection using a microfluidic cell separation system with a dielectrophoretic array. The enriched tumor cells were subjected to whole-genome amplification (WGA) followed by genome sequencing. The FTC analysis detected an EGFR exon 19 deletion in Case 1 (12/19 cells, 63.2%), and EML4-ALK fusion (17/20 cells, 85%) with an alectinib-resistant mutation of ALK (p.G1202R) in Case 2. To eliminate WGA-associated errors and increase the uniformity of the WGA product, the protocol was revised to sequence multiple single FTCs individually. An analytical pipeline, accurate single-cell mutation detector (ASMD), was developed to identify somatic mutations of FTCs. The large numbers of WGA-associated errors were cleaned up, and the somatic mutations detected in FTCs by ASMD were concordant with those found in tissue specimens. This protocol is applicable to circulating tumor cells analysis of peripheral blood and expands the possibility of utilizing molecular profiling of cancers.

Applications of liquid biopsy in the Pharmacological Audit Trail for anticancer drug development

Anticancer drug development is a costly and protracted activity, and failure at late phases of clinical testing is common. We have previously proposed the Pharmacological Audit Trail (PhAT) intended to improve the efficiency of drug development, with a focus on the use of tumour tissue-based biomarkers. Blood-based 'liquid biopsy' approaches, such as targeted or whole-genome sequencing studies of plasma circulating cell-free tumour DNA (ctDNA) and circulating tumour cells (CTCs), are of increasing relevance to this drug development paradigm. Liquid biopsy assays can provide quantitative and qualitative data on prognostic, predictive, pharmacodynamic and clinical response biomarkers, and can also enable the characterization of disease evolution and resistance mechanisms. In this Perspective, we examine the promise of integrating liquid biopsy analyses into the PhAT, focusing on the current evidence, advances, limitations and challenges. We emphasize the continued importance of analytical validation and clinical qualification of circulating tumour biomarkers through prospective clinical trials.

Current treatment and future challenges in ROS1- and ALK-rearranged advanced non-small cell lung cancer

Non─small cell lung cancer (NSCLC) presents different druggable genetic abnormalities, including ROS1 and ALK rearrangements, which share relevant clinical features and therapeutic strategies. The homology between the tyrosine kinase domains of ROS1 and ALK defines unique subsets of patients highly sensitive to targeted tyrosine kinase inhibitors (TKIs). Genomic profiling in advanced NSCLC is standard, immunohistochemistry and fluorescence in situ hybridization being the main techniques used to detect genomic rearrangements. Personalized treatment with TKIs in ROS1- and ALK-positive NSCLC patients has dramatically improved patients' outcomes. Crizotinib has been the first-line standard of care treatment in ALK-rearranged NSCLC patients for a long time, while crizotinib still represents the best upfront therapeutic option in ROS1-positive NSCLC patients, followed by next-generation TKIs at the time of disease progression. However, the improved intracranial efficacy of next-generation TKIs has led to these drugs becoming first-line options, widening treatment opportunities for these patients. Since all patients will develop disease progression under TKI therapy, understanding the mechanisms of acquired resistance is crucial to define the optimal sequential therapeutic strategy. Despite the positive correlation between personalized treatment and patients' outcome, access to next-generation TKIs and genomic profiling at the time of disease progression are major challenges to achieving this goal. In this review, we present updated evidence on ROS1- and ALK-rearranged NSCLC regarding epidemiology and diagnostics, current therapies and the most suitable sequential treatment approaches, as well as mechanisms of acquired resistance and strategies to overcome them.

Transformation from adenocarcinoma to squamous cell lung carcinoma with MET amplification after lorlatinib resistance: A case report

To date, several studies have described the mechanism of resistance to first- or second-generation anaplastic lymphoma kinase (ALK) inhibitors. Secondary ALK mutations, ALK gene amplification, and other bypass signal activations (i.e., KRAS mutation, EGFR mutation, amplification of KIT, and increased autophosphorylation of EGFR) are known as resistance mechanisms. However, little has been previously reported on acquired resistance mechanisms to lorlatinib. Here, we report a case of a patient with ALK-positive lung adenocarcinoma that acquired resistance to lorlatinib during treatment for brain metastasis and showed histological transformation to squamous cell carcinoma with MET amplification. We also review the previous literature on the resistance mechanism to ALK inhibitors.

Decoding the Evolutionary Response to Ensartinib in Patients With ALK-Positive NSCLC by Dynamic Circulating Tumor DNA Sequencing

INTRODUCTION

By implementing dynamic circulating tumor DNA (ctDNA) analysis, we explored the impact of TP53 mutations on tumor evolution and resistance mechanisms to ensartinib in patients with ALK-positive NSCLC.

METHODS

In a multicenter phase 2 trial, patients with ALK-positive NSCLC who progressed on crizotinib were treated with ensartinib. Blood samples for ctDNA analysis were collected at baseline, cycle 3 day 1, and progression disease (PD) and analyzed with a 212-gene panel.

RESULTS

A total of 440 samples were collected from 168 patients. Baseline TP53 mutations (20.2%) significantly correlated with inferior progression-free survival (4.2 mo versus 11.7 mo, p < 0.0001). Patients with TP53 mutations had higher mutation load than those without TP53 mutations at baseline (13.79 ± 3.72 versus 4.67 ± 0.39, p < 0.001). Although there was no significant difference in mutation load between these groups at cycle 3 day 1 (5.89 ± 2.25 versus 3.72 ± 0.62, p = 0.425), patients with mutated TP53 developed more mutations at PD (7.07 ± 1.25 versus 3.20 ± 0.33, p = 0.003). Frequency and abundance of secondary ALK mutations G1269A, G1202R, and E1210K increased markedly at PD than baseline. In patients without secondary ALK mutations, we identified ALK-independent resistance mechanisms including bypass signaling activation, downstream effector protein reactivation, epithelial-mesenchymal transformation, and epigenetic dysregulation.

CONCLUSIONS

Our study highlighted the advantage of ctDNA analysis for monitoring tumor evolution. TP53 mutations promoted genetic evolution and accelerated occurrence of resistance. We also unveiled ALK-dependent resistance mechanisms, mainly by G1269A, G1202R, and E1210K mutations, and ALK-independent resistance mechanisms to ensartinib.

ESCO2 promotes lung adenocarcinoma progression by regulating hnRNPA1 acetylation

BACKGROUND

Emerging evidence indicates that metabolism reprogramming and abnormal acetylation modification play an important role in lung adenocarcinoma (LUAD) progression, although the mechanism is largely unknown.

METHODS

Here, we used three public databases (Oncomine, Gene Expression Omnibus [GEO], The Cancer Genome Atlas [TCGA]) to analyze ESCO2 (establishment of cohesion 1 homolog 2) expression in LUAD. The biological function of ESCO2 was studiedusing cell proliferation, colony formation, cell migration, and invasion assays in vitro, and mouse xenograft models in vivo. ESCO2 interacting proteins were searched using gene set enrichment analysis (GSEA) and mass spectrometry. Pyruvate kinase M1/2 (PKM) mRNA splicing assay was performed using RT-PCR together with restriction digestion. LUAD cell metabolism was studied using glucose uptake assays and lactate production. ESCO2 expression was significantly upregulated in LUAD tissues, and higher ESCO2 expression indicated worse prognosis for patients with LUAD.

RESULTS

We found that ESCO2 promoted LUAD cell proliferation and metastasis metabolic reprogramming in vitro and in vivo. Mechanistically, ESCO2 increased hnRNPA1 (heterogeneous nuclear ribonucleoprotein A1) binding to the intronic sequences flanking exon 9 (EI9) of PKM mRNA by inhibiting hnRNPA1 nuclear translocation, eventually inhibiting PKM1 isoform formation and inducing PKM2 isoform formation.

CONCLUSIONS

Our findings confirm that ESCO2 is a key factor in promoting LUAD malignant progression and suggest that it is a new target for treating LUAD.

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

Simple Summary

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

Abstract

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

How to select the best upfront therapy for metastatic disease? Focus on ALK-rearranged non-small cell lung cancer (NSCLC)

Anaplastic lymphoma kinase (ALK) inhibitors have demonstrated robust clinical activity in patients with ALK-rearranged lung cancers. The echinoderm microtubule-associated protein-like (EML)-ALK translocation was first discovered in 2007 and 4 years later, crizotinib, a first-generation ALK inhibitor was approved. Since then, subsequent generations of ALK inhibitors have demonstrated superior efficacy and better CNS activity compared to crizotinib. Alectinib and brigatinib, both second-generation ALK inhibitors have been compared directly to crizotinib in the first-line setting and has demonstrated improved progression free survival (PFS) and intracranial response. Ceritinib, another second-generation ALK inhibitor has been shown to be superior to chemotherapy in ALK-rearranged disease with good CNS activity. Initial responses to ALK inhibitors are not always durable and resistance can occur as on-target or off-target alterations. Lorlatinib, a third-generation ALK inhibitor, has demonstrated activity in the treatment naïve setting and in resistance to crizotinib and second-generation ALK inhibitors. Lorlatinib has also shown improved PFS in patients harboring EML4-ALK variant 3, which is associated with the development of ALK resistance mutations, specifically G1202R. Another new ALK inhibitor, ensartinib, has demonstrated efficacy in the first-line setting and in alectinib refractory disease. Additional studies are underway examining mechanisms of resistance and best treatment options post resistance.

Resistance to anaplastic lymphoma kinase inhibitors: knowing the enemy is half the battle won

Anaplastic lymphoma kinase (ALK) translocations are responsible of neoplastic transformation in a limited subset of non-small cell lung cancer (NSCLC) patients. In recent years outcomes of these patients improved due to the development and clinical availability of specific and extremely active targeted therapies [i.e., next-generation Tyrosine Kinase Inhibitors (TKI)]: ALK+ patients are now reaching impressive results when treated with more potent inhibitors upfront with an average median progression-free survival (mPFS) around 35 months. However, under drug pressure, cancer cells develop resistance and patients eventually progress. Multiple mechanisms of intrinsic or acquired resistance have been extensively characterized. Less potent ALK inhibitors (ALKi)—like crizotinib—usually tend to induce a large spectrum of secondary intra-kinase mutations; however, these alterations may be observed also after sequential administration of multiple ALKi. Noteworthy, neoplastic cells may evade ALK targeting through a myriad of different mechanisms involving cell-stroma interaction, activation of parallel signaling pathways, intracellular downstream adaptation and histological reshaping, as relevant molecular events. Often these phenomena are restricted to a limited number of cases or even can be patient-specific, thus hindering the development of therapeutic strategies largely applicable. Consequently, the recognition of specific resistance mechanisms seldom translates in clinical opportunities. Management of ALK+ patients is drastically changed and deciphering the molecular biology underlying this disease during treatment is of paramount relevance. The bedrock of resistance to TKI is that, after the diagnosis, we face with a different disease that needs to be re-characterized through tissue or/and liquid biopsies. Understanding molecular pathways driving the resistant phenotype will give us the chance to know what we are dealing with and, rather than choose an empirical approach, will help us to properly define the best targeted treatment for these patients.

Sequential therapy of crizotinib followed by alectinib for non-small cell lung cancer harbouring anaplastic lymphoma kinase rearrangement (WJOG9516L): A multicenter retrospective cohort study

BACKGROUND

The data of sequential therapy of anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitors (TKIs) in clinical practice have been limited.

METHODS

We reviewed the clinical data of patients with ALK-rearranged non-small cell lung cancer who received crizotinib (CRZ) or alectinib (ALEC) between May 2012 and December 2016. Patients were divided into two groups based on the first-administered ALK-TKI, the CRZ or ALEC group. The combined time-to-treatment failure (TTF) was defined as the sum of the 'TTF of CRZ' plus the 'TTF of ALEC' if patients were treated with CRZ followed by ALEC in the CRZ group. The primary end-point is the comparison between the combined TTF and the TTF of ALEC in the ALEC group.

RESULTS

Of 864 patients enrolled from 61 institutions, 840 patients were analysed. There were 535 of 305 patients in the CRZ/ALEC groups. The combined TTF in the CRZ group was significantly longer than TTF in the ALEC group (median, 34.4 versus 27.2 months; hazard ratio [HR], 0.709; P = 0.0044). However, there was no significant difference in overall survival (OS) between the patients who received ALEC after CRZ in the CRZ group and the patients in the ALEC group (median, 88.4 months versus. not reached; HR, 1.048; P = 0.7770). In the whole population, the CRZ group had a significantly shorter OS than the ALEC group (median, 53.6 months versus not reached; HR, 1.821, P < 0.0001).

CONCLUSION

The combined TTF in the CRZ group was significantly longer than the TTF in the ALEC group; however, OS benefit of sequential therapy against ALEC as the first ALK-TKI was not shown.

Therapeutic Sequencing in ALK+ NSCLC

Anaplastic lymphoma kinase-rearranged non-small-cell lung cancer (ALK⁺ NSCLC) is a model disease for the use of targeted pharmaceuticals in thoracic oncology. Due to higher systemic and intracranial efficacy, the second-generation ALK tyrosine kinase inhibitors (TKI) alectinib and brigatinib have irrevocably displaced crizotinib as standard first-line treatment, based on the results of the ALEX and ALTA-1L trials. Besides, lorlatinib and brigatinib are the preferred second-line therapies for progression under second-generation TKI and crizotinib, respectively, based on the results of several phase II studies. Tissue or liquid rebiopsies at the time of disease progression, even though not mandated by the approval status of any ALK inhibitor, are gaining importance for individualization and optimization of patient management. Of particular interest are cases with off-target resistance, for example MET, HER2 or KRAS alterations, which require special therapeutic maneuvers, e.g., inclusion in early clinical trials or off-label administration of respectively targeted drugs. On the other hand, up to approximately half of the patients failing TKI, develop anatomically restricted progression, which can be initially tackled with local ablative measures without switch of systemic therapy. Among the overall biologically favorable ALK⁺ tumors, with a mean tumor mutational burden uniquely below 3 mutations per Mb and the longest survival among NSCLC currently, presence of the EML4-ALK fusion variant 3 and/or TP53 mutations identify high-risk cases with earlier treatment failure and a need for more aggressive surveillance and treatment strategies. The potential clinical utility of longitudinal ctDNA assays for earlier detection of disease progression and improved guidance of therapy in these patients is a currently a matter of intense investigation. Major pharmaceutical challenges for the field are the development of more potent, fourth-generation TKI and effective immuno-oncological interventions, especially ALK-directed cell therapies, which will be essential for further improving survival and achieving cure of ALK⁺ tumors.

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

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

Treatment of Brain Metastases of Non-Small Cell Lung Carcinoma

Lung cancer is one of the most common malignant neoplasms. As a result of the disease's progression, patients may develop metastases to the central nervous system. The prognosis in this location is unfavorable; untreated metastatic lesions may lead to death within one to two months. Existing therapies-neurosurgery and radiation therapy-do not improve the prognosis for every patient. The discovery of Epidermal Growth Factor Receptor (EGFR)-activating mutations and Anaplastic Lymphoma Kinase (ALK) rearrangements in patients with non-small cell lung adenocarcinoma has allowed for the introduction of small-molecule tyrosine kinase inhibitors to the treatment of advanced-stage patients. The Epidermal Growth Factor Receptor (EGFR) is a transmembrane protein with tyrosine kinase-dependent activity. EGFR is present in membranes of all epithelial cells. In physiological conditions, it plays an important role in the process of cell growth and proliferation. Binding the ligand to the EGFR causes its dimerization and the activation of the intracellular signaling cascade. Signal transduction involves the activation of MAPK, AKT, and JNK, resulting in DNA synthesis and cell proliferation. In cancer cells, binding the ligand to the EGFR also leads to its dimerization and transduction of the signal to the cell interior. It has been demonstrated that activating mutations in the gene for EGFR-exon19 (deletion), L858R point mutation in exon 21, and mutation in exon 20 results in cancer cell proliferation. Continuous stimulation of the receptor inhibits apoptosis, stimulates invasion, intensifies angiogenesis, and facilitates the formation of distant metastases. As a consequence, the cancer progresses. These activating gene mutations for the EGFR are present in 10-20% of lung adenocarcinomas. Approximately 3-7% of patients with lung adenocarcinoma have the echinoderm microtubule-associated protein-like 4 (EML4)/ALK fusion gene. The fusion of the two genes EML4 and ALK results in a fusion gene that activates the intracellular signaling pathway, stimulates the proliferation of tumor cells, and inhibits apoptosis. A new group of drugs-small-molecule tyrosine kinase inhibitors-has been developed; the first generation includes gefitinib and erlotinib and the ALK inhibitor crizotinib. These drugs reversibly block the EGFR by stopping the signal transmission to the cell. The second-generation tyrosine kinase inhibitor (TKI) afatinib or ALK inhibitor alectinib block the receptor irreversibly. Clinical trials with TKI in patients with non-small cell lung adenocarcinoma with central nervous system (CNS) metastases have shown prolonged, progression-free survival, a high percentage of objective responses, and improved quality of life. Resistance to treatment with this group of drugs emerging during TKI therapy is the basis for the detection of resistance mutations. The T790M mutation, present in exon 20 of the EGFR gene, is detected in patients treated with first- and second-generation TKI and is overcome by Osimertinib, a third-generation TKI. The I117N resistance mutation in patients with the ALK mutation treated with alectinib is overcome by ceritinib. In this way, sequential therapy ensures the continuity of treatment. In patients with CNS metastases, attempts are made to simultaneously administer radiation therapy and tyrosine kinase inhibitors. Patients with lung adenocarcinoma with CNS metastases, without activating EGFR mutation and without ALK rearrangement, benefit from immunotherapy. This therapeutic option blocks the PD-1 receptor on the surface of T or B lymphocytes or PD-L1 located on cancer cells with an applicable antibody. Based on clinical trials, pembrolizumab and all antibodies are included in the treatment of non-small cell lung carcinoma with CNS metastases.

Upfront Management of ALK-Rearranged Metastatic Non-small Cell Lung Cancer: One Inhibitor Fits All?

PURPOSE OF REVIEW

Anaplastic lymphoma kinase (ALK) rearrangements represent a seldom event in non-small cell lung cancer (NSCLC). Given the oncogene alteration, ALK targeting represents the main therapeutic strategy. Here, we review evidence regarding ALK inhibitors (ALKi): clinical activity, safety profiles, financial costs, and biomarkers of efficacy.

RECENT FINDINGS

During the past 10 years, multiple ALKi have been developed, and four different compounds are currently available as upfront options for ALK+ NSCLC patients: crizotinib, ceritinib, alectinib, and brigatinib. Second-generation (2G) ALKi demonstrated superior clinical activity in terms of median progression-free survival (mPFS), objective response rate (ORR), intracranial disease control, and duration of response (DOR) when compared with crizotinib. 2G ALKi represent the current gold-standard first-line treatment for ALK-rearranged metastatic NSCLC. Among all available options, in our opinion, alectinib has likely the best profile of clinical activity and safety, thus emerging as the best upfront therapy. More insights will come from ongoing trials and analysis of biomarkers.

Treatment Sequencing for Anaplastic Lymphoma Kinase-Rearranged Non-Small-Cell Lung Cancer

Non-small-cell lung cancer (NSCLC) accounts for about 85% of all lung cancer cases and is the leading cause of cancer-related deaths. Most NSCLC patients are diagnosed with advanced disease and require systemic treatment. Despite emerging advances in chemotherapy and immunotherapy, the prognosis of stage IV patients remains poor. However, the discovery of oncogenic driver mutations including mutations in the epidermal growth factor receptor (EGFR), the anaplastic lymphoma kinase (ALK) and others, characterize a subset of patients with the opportunity of targeted therapies. Fusions between the ALK and echinoderm microtubule-associated protein-like 4 (EML4) are present in ∼ 3-5% of patients with NSCLC. Several first-, second-, and third-generation ALK tyrosine kinase inhibitors (TKIs) have been developed in the last decade and have tremendously changed treatment options and outcomes of ALK-positive NSCLC patients. With increasing treatment options, treatment sequence decisions have become more and more complex. ALK-mutations, fusion variants, or activation of by-pass pathways result in treatment resistance during the course of treatment in nearly all patients. Mutation-guided treatment sequencing can lead to better outcomes, and re-biopsy or liquid-biopsy should be performed whenever possible in case of disease progression in ALK-rearranged patients. In the future, combinational treatment of ALK TKIs with other pathway-inhibitors might further improve patients' treatment options and outcomes. Here, we review the data for currently available ALK TKIs, discuss approaches of treatment sequencing, and give an outlook on emerging developments.

Safety of lorlatinib following alectinib-induced pneumonitis in two patients with ALK-rearranged non-small cell lung cancer: a case series

Drug-induced interstitial lung disease (DI-ILD) is a rare adverse event associated with targeted therapies that inhibit the anaplastic lymphoma kinase (ALK) protein. Although newer-generation ALK inhibitors such as alectinib significantly improve survival in metastatic ALK-rearranged non-small cell lung cancer (NSCLC), the risk of DI-ILD is similar to that of earlier-generation therapies. Lorlatinib is a third-generation ALK inhibitor that is active in patients with metastatic NSCLC whose tumors have developed secondary resistance to alectinib. While it is associated with low rates of DI-ILD in initial phase 1/2 clinical trials, the safety of lorlatinib in patients with a history of DI-ILD has not been well-described. In this case series, we therefore report two patients with metastatic ALK-rearranged NSCLC who each tolerated lorlatinib following recovery from alectinib-related DI-ILD. Both cases were notable for the acute onset of dyspnea, hypoxia, and diffuse ground-glass opacities within one month of initiating alectinib. With no alternative etiology of pneumonitis identified, both patients were treated empirically for grade 3 DI-ILD with corticosteroids and discontinuation of alectinib. Following rapid clinical recovery and eventual radiographic resolution of opacities, each patient was started on lorlatinib at the time of cancer progression, with neither person developing symptoms or radiographic findings consistent with recurrent DI-ILD. In the following series, we describe these two cases in greater detail and discuss their significance within the context of the prior literature. While further descriptions are needed, our experience suggests that lorlatinib may be a safe therapeutic option in some patients who have recovered from DI-ILD.

The Emerging Therapeutic Landscape of ALK Inhibitors in Non-Small Cell Lung Cancer

The treatment of metastatic non-small cell lung cancer (NSCLC) has undergone a paradigm shift over the last decade. Better molecular characterization of the disease has led to the rapid improvement of personalized medicine and the prompt delivery of targeted therapies to patients with NSCLC. The discovery of the EML4-ALK fusion gene in a limited subset of patients affected by NSCLC and the subsequent clinical development of crizotinib in 2011 has been an impressive milestone in lung cancer research. Unfortunately, acquired resistances regularly develop, hence disease progression occurs. Afterward, modern tyrosine kinase inhibitors (TKIs), such as ceritinib, alectinib, brigatinib, and lorlatinib, have been approved by the Food and Drug Administration (FDA) for the management of anaplastic lymphoma kinase (ALK)-positive NSCLCs. Several compounds are currently under investigation to achieve the optimal strategy of therapy. Additionally, the results of ongoing clinical trials with novel-generation TKI will provide more evidence on the best sequence in the treatment of ALK-positive NSCLC patients. In this review, we provide a comprehensive overview of the state-of-the-art targeted therapy options in ALK-positive NSCLCs. Resistance, potential therapeutic strategies to overcome drug resistance, and future perspectives for this subset of patients are critically analyzed and summarized.

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

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

Is there any place for immune-checkpoint inhibitors in the treatment algorithm of fusion-driven non-small cell lung cancer?-a literature review

The advent of immune-checkpoint inhibitors (ICIs) targeting the programmed death-1 (PD-1)/programmed death ligand-1 (PD-L1) axis, produced a paradigm change of the treatment algorithm for metastatic, non-oncogene addicted, non-small cell lung cancer (NSCLC). However, the majority of patients with oncogene-addicted disease have been excluded from the "immunotherapy revolution", thus the clinical efficacy of these agents in this subset of patients remains largely unknown. Although pre-clinical evidence provided a good rationale to pursue the investigation of ICI treatment in specific subgroups of oncogene-addicted NSCLC, current available evidence suggested that tumors harboring molecular alterations likely do not represent the best candidate to single agent ICI therapy. Furthermore, the prospect of further improving overall survival (OS) with the combination of tyrosine kinase inhibitors (TKIs) and ICIs led to unexpected poor results and safety issues in recent phase I trials exploring different therapeutic associations. Conversely, the combination of immunotherapy and chemotherapy is emerging as a potential effective strategy in specific subsets of NSCLC patients harboring oncogenic drivers. In this review we particularly focus on the subgroup of patients whose disease harbor oncogenic rearrangements, summarizing current evidence from preclinical and clinical studies and discussing their practical implications, in order to define the potential role of ICIs in the clinical management of fusion-driven NSCLC.