Will the clinical development of 4th-generation "double mutant active" ALK TKIs (TPX-0131 and NVL-655) change the future treatment paradigm of ALK+ NSCLC?

ALK-based dual inhibitors: Focus on recent development for non-small cell lung cancer therapy

As a prevalent oncogenic driver gene in non-small cell lung cancer (NSCLC), ALK represents a crucial and efficacious therapeutic target. To date, seven ALK inhibitors have been approved for ALK fusion-positive NSCLC, with several others undergoing clinical trials. These therapies demonstrate significant efficacy in ALK fusion-positive NSCLC patients. However, acquired resistance mechanisms, including ALK kinase domain mutations, ALK gene amplification, and bypass pathway activation, significantly compromise the efficacy of targeted therapy in ALK fusion-positive NSCLC. Therefore, the discovery of novel ALK inhibitors and the development of related treatment strategies remain critical. Compared to the combination therapy strategy based on ALK inhibitors, dual-target inhibitors (targeting two distinct pathways within a single molecule) may reduce systemic toxicity and mitigate resistance mechanisms in cancer treatment. Notably, recent years have witnessed remarkable progress in dual-target ALK inhibitor development for NSCLC. Consequently, this review aims to summarize the advancements achieved through dual ALK-based inhibitors in NSCLC therapy, analyze their rational design and structure-activity relationships, and provide perspectives for overcoming resistance through next-generation inhibitors and innovative therapeutic approaches.

Advances of dual inhibitors based on ALK for the treatment of cancer

Anaplastic lymphoma kinase (ALK), which encodes a highly conserved receptor tyrosine kinase (RTK), is important for the development and progression of many tumors, especially non-small cell lung cancer (NSCLC). Currently, third-generation ALK inhibitors are used to treat ALK-mutant NSCLC, but the rapid emergence of resistance during treatment greatly limits their efficacy in clinic. In comparison to single-target inhibitors, ALK dual inhibitors offer the benefits of reducing the emergence of drug resistance, improving treatment efficacy, and optimizing pharmacokinetic features due to the synergistic function of ALK and other associated targets involved in tumor progression. Therefore, we outline the development of ALK dual inhibitors, highlight their design approaches and structure-activity relationship (SAR), and offer insights into new challenges and potential future directions in this area.

ALK in cancer: from function to therapeutic targeting

Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase (RTK) that acts as an oncogenic driver in solid and haematological malignancies in both children and adults. Although ALK-expressing (ALK+) tumours show strong initial responses to the series of ALK inhibitors currently available, many patients will develop resistance. In this Review, we discuss recent advances in ALK oncogenic signalling, together with existing and promising new modalities to treat ALK-driven tumours, including currently approved ALK-directed therapies, namely tyrosine kinase inhibitors, and novel approaches such as ALK-specific immune therapies. Although ALK inhibitors have changed the management and clinical history of ALK+ tumours, they are still insufficient to cure most of the patients. Therefore, more effort is needed to further improve outcomes and prevent the tumour resistance, recurrence and metastatic spread that many patients with ALK+ tumours experience. Here, we outline how a multipronged approach directed against ALK and other essential pathways that sustain the persistence of ALK+ tumours, together with potent or specific immunotherapies, could achieve this goal. We envision that the lessons learned from treating ALK+ tumours in the clinic could ultimately accelerate the implementation of innovative combination therapies to treat tumours driven by other tyrosine kinases or oncogenes with similar properties.

Mechanisms of Resistance to ALK Inhibitors and Corresponding Treatment Strategies in Lung Cancer

Lung cancer continues to be a leading cause of cancer-related mortality and morbidity worldwide. The echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase (EML4-ALK) fusion gene accounts for approximately 3%-5% of gene mutation types. Targeted therapies for ALK mutations have made significant advancements in recent decades, enabling a considerable number of patients to achieve the goal of five-year survival benefits. However, overcoming the drug resistance that arises with current ALK tyrosine kinase inhibitors (TKIs) remain a major challenge in ALK-targeted therapies. In this review, we briefly discuss the primary and secondary mechanisms of resistance to ALK-TKIs, and explore treatment strategies based on progressive resistance models. Meanwhile, novel drugs and combination therapies are being actively researched and developed to address these challenges. The aim is to offer new insights into the mechanisms of resistance and the corresponding treatment strategies to ALK inhibitors.

Recent advances in therapeutic strategies for non-small cell lung cancer

The development of targeted therapy with small-molecule tyrosine kinase inhibitors and immunotherapy with immune checkpoints inhibitors has ushered in the era of precision medicine in treating lung cancer, which remains the leading cause of cancer-related deaths worldwide. Both targeted therapy and immunotherapy have significantly improved the survival of patients with metastatic non-small-cell lung cancer (NSCLC). Additionally, recent groundbreaking studies have demonstrated their efficacy in both the perioperative setting and following concurrent chemoradiotherapy in early-stage NSCLC. Despite significant advancements in first-line treatment options, disease progression remains inevitable for most patients with advanced NSCLC, necessitating the exploration and optimization of subsequent therapeutic strategies. Emerging novel agents are expanding treatment options in the first-line setting and beyond. Recently, emerging bispecific antibodies have shown enhanced efficacy. For instance, amivantamab has been approved as a treatment for epidermal growth factor receptor (EGFR)-mutant NSCLC, including those with EGFR exon 20 insertion mutations. Additionally, antibody-drug conjugates (ADCs), including HER2-targeting trastuzumab deruxtecan, TROP2-targeting ADCs, HER3-targeting patritumab deruxtecan, and MET-targeting telisotuzumab vedotin, have demonstrated promising outcomes in several clinical trials. This review summarizes the recent advancements and challenges associated with the evolving NSCLC therapeutic landscape.

Update advances in anaplastic lymphoma kinase-positive non-small cell lung cancer treatment

Lung cancer is the leading cause of cancer death worldwide. However, since the discovery and development of targeted therapies and immune checkpoint inhibitors, it has been a dramatically improved in survival outcomes and quality of life. Anaplastic lymphoma kinase (ALK) rearrangements occur in approximately 5% of patients with advanced non-small cell lung cancer (NSCLC), and the introduction of ALK tyrosine kinase inhibitors (TKIs) has changed the treatment paradigm. Although head-to-head randomized controlled trials for late generation inhibitors are lacking, the authors will review the current available options, treatments efficacy, safety profiles, ALK mechanisms of resistance, as well as new promising treatments in this field.

GUK1 activation is a metabolic liability in lung cancer

Little is known about metabolic vulnerabilities in oncogene-driven lung cancer. Here, we perform a phosphoproteomic screen in anaplastic lymphoma kinase (ALK)-rearranged ("ALK+") patient-derived cell lines and identify guanylate kinase 1 (GUK1), a guanosine diphosphate (GDP)-synthesizing enzyme, as a target of ALK signaling in lung cancer. We demonstrate that ALK binds to and phosphorylates GUK1 at tyrosine 74 (Y74), resulting in increased GDP biosynthesis. Spatial imaging of ALK+ patient tumor specimens shows enhanced phosphorylation of GUK1 that significantly correlates with guanine nucleotides in situ. Abrogation of GUK1 phosphorylation reduces intracellular GDP and guanosine triphosphate (GTP) pools and decreases mitogen-activated protein kinase (MAPK) signaling and Ras-GTP loading. A GUK1 variant that cannot be phosphorylated (Y74F) decreases tumor proliferation in vitro and in vivo. Beyond ALK, other oncogenic fusion proteins in lung cancer also regulate GUK1 phosphorylation. These studies may pave the way for the development of new therapeutic approaches by exploiting metabolic dependencies in oncogene-driven lung cancers.

Diverse clinical outcomes for the EGFR‑mutated and ALK‑rearranged advanced non‑squamous non‑small cell lung cancer

EGFR and ALK are key driver mutations in non-small cell lung cancer (NSCLC). Tyrosine kinase inhibitors are recommended as the first-line treatment for advanced NSCLC with driving oncogenes because they have fewer side effects and provide better disease control than chemotherapy. The present retrospective analysis aimed to investigate how altered driver genes impact cancer outcomes and clinical presentation. A total of 628 patients with advanced-stage NSCLC and documented EGFR and ALK mutations were enrolled at Changhua Christian Hospital in Taiwan between August 2011 and January 2021. EGFR mutations were identified by PCR. ALK rearrangements were identified by immunostaining. Patients without EGFR or ALK mutations were labeled as wild-type (WT). EGFR mutation was detected in 446 (71.02%) patients, ALK rearrangement in 36 (5.73%) patients and WT in 146 (23.25%) patients. EGFR mutations resulted in higher frequency of lung, brain and multiple extrapulmonary metastases than ALK rearrangement. The ALK group exhibited the longest median overall survival (OS), followed by EGFR and WT groups (ALK: 51.60±13.32, EGFR: 24.03±1.22 and WT: 19.63±2.43 months, respectively; P=0.011). In patients with brain metastases, ALK group had a longer median OS than the EGFR group. Because there were few recruited patients with ALK rearrangement, the results were not significant. According to the results of Cox regression model analysis, driver mutations with EGFR and ALK, lower smoking pack-years, younger age, better performance status, no pleural metastasis and fewer extrapulmonary metastases were key prognostic factors. In conclusion, diverse clinical outcomes are driven by different driver mutations. EGFR mutation leads to more extrapulmonary metastases. Median OS was superior in ALK-rearranged NSCLC than EGFR-mutated NSCLC regardless of brain metastases.

In-depth theoretical modeling to explore the mechanism of TPX-0131 overcoming lorlatinib resistance to ALKL1196M/G1202R mutation

A number of anaplastic lymphoma kinase (ALK) inhibitors have been clinically approved, with lorlatinib, particularly as a third-generation drug, demonstrating efficacy against various drug-resistant ALK single mutations. However, continued clinical use of lorlatinib has led to the emergence of ALK double mutations conferring resistance to lorlatinib, notably ALKL1196M/G1202R. TPX-0131 is a potential fourth-generation ALK inhibitor currently under development. TPX-0131 demonstrates a broader spectrum of activity against ALK-resistant mutations, efficiently inhibiting 26 single-point mutations and various double/triple mutations, including solvent front mutations and gatekeeper mutations. In this study, for the first time, a comprehensive elucidation of the molecular mechanisms by which TPX-0131 overcomes lorlatinib resistance to ALKL1196M/G1202R through modeling, MD simulations, free energy calculations, and US simulations. The results indicate that the interactions between lorlatinib and key residues at the hinge region are disturbed by L1196M/G1202R double mutation, leading to the disruption of important hydrogen bonding between Glu1197 and lorlatinib. For TPX-0131, the L1196M/G1202R mutation enhances electrostatic and van der Waals interactions, causing significant conformational changes primarily in the hinge region, G-loop, and β-strands. The tight binding of TPX-0131 to residues Arg1202, Met1199 and Arg1120 contribute significantly to overcoming lorlatinib resistance in ALKL1196M/G1202R mutant. These research results are expected to offer insights into the mechanism of TPX-0131 in treating ALKG1202R/L1196M-induced NSCLC resistance and optimizing of ALK inhibitors.

An ultra-fast green ultra-high-performance liquid chromatography-tandem mass spectrometry method for estimating the in vitro metabolic stability of zotizalkib in human liver microsomes

Zotizalkib (ZTK, TPX-0131) is a fourth-generation highly effective inhibitor of wild-type anaplastic lymphoma kinase (ALK) and ALK-resistant mutations that can penetrate the central nervous system. It exhibited greater potency compared to all five officially approved ALK inhibitors. The aim of this study was to develop a rapid, accurate, eco-friendly, and highly sensitive ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method for measuring the concentration of ZTK in human liver microsomes (HLMs). The validation aspects of the current UHPLC-MS/MS methodology in the HLMs were conducted in accordance with the bioanalytical method validation standards specified by the US Food and Drug Administration. ZTK and encorafenib were separated using an Agilent C8 column (Eclipse Plus) and an isocratic mobile phase. The calibration curve for the developed ZTK exhibited a linear relationship within the concentration range of 1-3000 ng/mL. The results from the Analytical Green-ness Metric Approach program (0.76) suggested that the created method demonstrated a significant degree of environmental sustainability. The in vitro half-life (t1/2) and intrinsic clearance (Clint) of ZTK were determined to be 15.79 min and 51.35 mL/min/kg, respectively that suggests the ZTK exhibits characteristics similar to those of a medication with a high extraction ratio. These approaches are crucial for the progress of novel pharmaceutical development, especially in improving metabolic stability.

Developments in predictive biomarker testing and targeted therapy in advanced stage non-small cell lung cancer and their application across European countries

In the past two decades, the treatment of metastatic non-small cell lung cancer (NSCLC), has undergone significant changes due to the introduction of targeted therapies and immunotherapy. These advancements have led to the need for predictive molecular tests to identify patients eligible for targeted therapy. This review provides an overview of the development and current application of targeted therapies and predictive biomarker testing in European patients with advanced stage NSCLC. Using data from eleven European countries, we conclude that recommendations for predictive testing are incorporated in national guidelines across Europe, although there are differences in their comprehensiveness. Moreover, the availability of recently EMA-approved targeted therapies varies between European countries. Unfortunately, routine assessment of national/regional molecular testing rates is limited. As a result, it remains uncertain which proportion of patients with metastatic NSCLC in Europe receive adequate predictive biomarker testing. Lastly, Molecular Tumor Boards (MTBs) for discussion of molecular test results are widely implemented, but national guidelines for their composition and functioning are lacking. The establishment of MTB guidelines can provide a framework for interpreting rare or complex mutations, facilitating appropriate treatment decision-making, and ensuring quality control.

Overcoming Central β-Sheet #6 (Cβ6) ALK Mutation (L1256F), TP53 Mutations and Short Forms of EML4-ALK v3/b and v5a/b Splice Variants are the Unmet Need That a Re-Imagined 5th-Generation (5G) ALK TKI Must Deliver

Despite the development and approval of seven anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitors (TKIs) spanning over three "generations" since the discovery of ALK fusion positive (ALK+) non-small cell lung cancer (NSCLC), there remains intrinsic and acquired resistances to these approved TKIs. Currently, a fourth-generation (4G) ALK TKI, NVL-655, is being developed to attack some of the unmet needs such as compound resistance mutations in cis. However, EML4-ALK variant 3 and TP53 mutations are intrinsic genomic alterations that negatively modulate efficacy of ALK TKIs. Potentially, in the shifting landscape where lorlatinib should be the first-line ALK TKI of choice based on the CROWN trial, the central β-sheet #6 (Cβ6) mutation ALK L1256F will be the potential acquired resistance mutation to lorlatinib which may be resistant to current ALK TKIs. Here we opine on what additional capacities a putative fifth-generation (5G) ALK TKI will need to possess if it can be achieved in one single molecule. We propose randomized trial schemas targeting some of the intrinsic resistance mechanisms that will lead to approval of a prototypic fifth-generation (5G) ALK TKI and actually be beneficial to ALK+ NSCLC patients rather than just design a positive pivotal superiority trial for the sole purpose of drug approval.

ALESIA 5-Year Update: Alectinib at 600 mg Twice Daily Gives Lorlatinib a Run for Its Money in Asia

Alectinib, a next-generation anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitor (TKI), has demonstrated superior progression-free survival over crizotinib with both 300 mg twice daily (J-ALEX) or 600 mg twice daily (ALEX, ALESIA) dosing in three pivotal clinical trials. Given the similar median PFS achieved in the J-ALEX trial and the Asian subgroup of the ALEX trial, there remains debate about the optimal alectinib dose for Asians. The third pivotal alectinib trial, ALESIA, which was conducted exclusively in Asia to support the registration of alectinib in China, utilized 600 mg alectinib twice daily. The mature PFS was not reached at the initial publication of ALESIA. At ESMO Asia 2022, the 5-year update of ALESIA was presented with an impressive mature investigator-assessed PFS of 41.6 months (95% CI 33.1-58.9), which is numerically longer than the mature PFS of 34.1 months achieved by alectinib at 300 mg twice daily in the J-ALEX trial. Based on these results, as well as retrospective pharmacokinetic and responses and PFS data, Alectinib at 600 mg twice daily is the optimal dose for Asians. This has been based on the ALESIA trial and on the retrospective pharmacokinetic and responses and PFS data and has set the benchmark for ALK TKI as the first-line treatment for advanced ALK+ NSCLC in Asia. Importantly, lorlatinib, another next generation ALK TKI, also achieved an impressive hazard ratio with a still immature PFS in all patients, including Asian patients, in a recent subgroup analysis after a median follow-up time of 36.7 months. We await the final mature PFS of lorlatinib overall and for Asian patients in the CROWN trial to see if lorlatinib will set a new standard.

Treatment of advanced ALK-rearranged NSCLC following second-generation ALK-TKI failure

INTRODUCTION

Anaplastic lymphoma kinase (ALK) gene rearrangement is detected in approximately 3-5% of non-small cell lung cancer (NSCLC) cases. Tyrosine kinase inhibitors (TKIs) targeting ALK rearrangement (ALK-TKIs) have shown significant efficacy and improved the survival of patients with NSCLC exhibiting ALK rearrangement. However, almost all patients exhibit disease progression during TKI therapy owing to resistance acquired through various molecular mechanisms, including both ALK-dependent and ALK-independent.

AREAS COVERED

Here, we review the mechanisms underlying resistance to second-generation ALK-TKIs, and the clinical management strategies following resistance in patients with ALK rearrangement-positive NSCLC.

EXPERT OPINION

Treatment strategies following the failure of second-generation ALK-TKIs failure should be based on resistant mechanisms. For patients with ALK mutations who exhibit resistance to second-generation ALK-TKIs, lorlatinib is the primary treatment option. However, the identification of resistance profiles of second-generation ALK-TKIs can aid in the selection of an appropriate treatment strategy. In cases of ALK-dependent resistance mutations, lorlatinib could be the first choice as it exhibits the broadest coverage of mutations that lead to resistance against second-generation ALK-TKIs, such as G1202R, and L1196M. In cases of no resistance mutations, atezolizumab, bevacizumab, and platinum-based chemotherapy could be the alternative treatment options.

From ASCEND-5 to ALUR to ALTA-3, an Anti-Climactic End to the Era of Randomized Phase 3 Trials of Next-Generation ALK TKIs in the Crizotinib-Refractory Setting

The competing roles of various next-generation ALK TKIs in the first and second line treatment setting of advanced ALK+ NSCLC were based on many phase 3 clinical trials in both the first-line and crizotinib-refractory settings. The approval of all next-generation ALK TKIs was first in the crizotinib-refractory setting, based on a large-scale Phase 2 trial, and was then followed by at least one global randomized phase 3 trial comparing to platinum-based chemotherapy (ASCEND-4) or to crizotinib (ALEX, ALTA-1L, eXalt3, CROWN). In addition, three randomized phase 3 trials in the crizotinib-refractory setting were also conducted by next-generation ALK TKIs that were developed earlier before the superiority of next-generation ALK TKIs was demonstrated in order to secure the approval of these ALK TKIs in the crizotinib-refractory setting. These three crizotinib-refractory randomized trials were: ASCEND-5 (ceritinib), ALUR (alectinib), and ALTA-3 (brigatinib). The outcome of the ATLA-3 trial was recently presented closing out the chapter where next-generation ALK TKIs were investigated in the crizotinib-refractory setting as they have replaced crizotinib as the standard of care first-line treatment of advanced ALK+ NSCLC. This editorial summarizes the results of next-generation ALK TKIs in randomized crizotinib-refractory trials and provides a perspective on how natural history of ALK+ NSCLC may potentially be altered with sequential treatment. ALTA-3 compared brigatinib to alectinib, showing that both achieved near identical blinded independent review committee (BIRC)-assessed progression-free survival (PFS) (19.2-19.3 months). Importantly, 4.8% of brigatinib-treated patients developed interstitial lung disease (ILD) while no alectinib-treated patients developed ILD. Dose reduction and discontinuation due to treatment-related adverse events were 21% and 5%, respectively, for brigatinib-treated patients compared to 11% and 2%, respectively, for alectinib-treated patients. Upon analysis of these findings, we speculate that brigatinib may have a diminishing role in the treatment of advanced ALK+ NSCLC.

Diverse Resistant Mechanisms Identified Using Serial Next-Generation Sequencing in a Patient With ALK-Rearranged Metastatic Lung Adenocarcinoma: A Case Report

Both tissue and plasma-based next generation sequencing (NGS) facilitate the identification of actionable oncogene alterations at diagnosis and resistant mechanisms on progression. The value of longitudinal profiling is less established among patients with ALK-rearranged NSCLC, underpinned by concerns of limited treatment options post-progression and assay sensitivity. We report a case of a patient with ALK-rearranged NSCLC with serial tissue and plasma NGS performed post-progression, whose results helped to guide sequencing of treatment options leading to an overall survival exceeding 8 years from diagnosis of metastatic disease.

Sustained Improvement in the Management of Patients with Non-Small-Cell Lung Cancer (NSCLC) Harboring ALK Translocation: Where Are We Running?

ALK translocation amounts to around 3-7% of all NSCLCs. The clinical features of ALK+ NSCLC are an adenocarcinoma histology, younger age, limited smoking history, and brain metastases. The activity of chemotherapy and immunotherapy is modest in ALK+ disease. Several randomized trials have proven that ALK inhibitors (ALK-Is) have greater efficacy with respect to platinum-based chemotherapy and that second/third generation ALK-Is are better than crizotinib in terms of improvements in median progression-free survival and brain metastases management. Unfortunately, most patients develop acquired resistance to ALK-Is that is mediated by on- and off-target mechanisms. Translational and clinical research are continuing to develop new drugs and/or combinations in order to raise the bar and further improve the results attained up to now. This review summarizes first-line randomized clinical trials of several ALK-Is and the management of brain metastases with a focus on ALK-I resistance mechanisms. The last section addresses future developments and challenges.

From preclinical efficacy to 2022 updated CROWN trial, lorlatinib is the preferred 1st-line treatment of advanced ALK+ NSCLC

Six ALK TKIs (crizotinib, ceritinib, alectinib, brigatinib, lorlatinib, ensartinib) have received first-line treatment indication of advanced ALK+ NSCLC in various countries. In Ba/F3 cells, lorlatinib achieved lowest IC₅₀ among these 6 ALK TKIs against EML4-ALK variant 1 or 3. In 2022, 7 abstracts reported updated efficacy and safety data from CROWN. With a median follow-up time of 36.7 months, the 3-year progression-free survival (PFS) rate was 63.5%. The median PFS of lorlatinib still has not been reached. Post-lorlatinib treatment median PFS2 was 74.0% at 3-years. Lorlatinib-treated Asian patients achieved similar 3-year PFS rate as overall lorlatinib-treated patients. Median PFS was 33.3 months among lorlatinib-treated EML4-ALK v3 patients. CNS AE occurred fewer than 1 per patient over the median follow-up time of 36.7 months and most resolved without intervention. Altogether these data affirm our belief that lorlatinib should be the treatment of choice of advanced ALK+ NSCLC.

ALK-positive lung cancer: a moving target

Anaplastic lymphoma kinase (ALK) is a potent oncogenic driver in lung cancer. ALK tyrosine kinase inhibitors yield significant benefit in patients with ALK fusion-positive (ALK+) lung cancers; yet the durability of response is limited by drug resistance. Elucidation of on-target resistance mechanisms has facilitated the development of next-generation ALK inhibitors, but overcoming ALK-independent resistance mechanisms remains a challenge. In this Review, we discuss the molecular underpinnings of acquired resistance to ALK-directed therapy and highlight new treatment approaches aimed at inducing long-term remission in ALK+ disease.

Comparative Efficacy of ALK Inhibitors for Treatment-Naïve ALK-Positive Advanced Non-Small Cell Lung Cancer with Central Nervous System Metastasis: A Network Meta-Analysis

Central nervous system (CNS) metastases and acquired resistance complicate the treatment of anaplastic lymphoma kinase (ALK) rearrangement-positive (ALK-p) advanced non-small cell lung cancer (NSCLC). Thus, this review aimed to provide a comprehensive overview of brain metastasis, acquired resistance, and prospects for overcoming these challenges. A network meta-analysis of relevant phase III randomized controlled trials was performed to compare the efficacies of multiple ALK inhibitors by drug and generation in overall patients with ALK-p untreated advanced NSCLC and a subgroup of patients with CNS metastases. The primary endpoint was progression-free survival (PFS). Generation-specific comparison results showed that third-generation ALK inhibitors were significantly more effective than second-generation ALK inhibitors in prolonging the PFS of the subgroup of patients with CNS metastases. Drug-specific comparison results demonstrated that lorlatinib was the most effective in prolonging PFS, followed by brigatinib, alectinib, ensartinib, ceritinib, crizotinib, and chemotherapy. While lorlatinib was superior to brigatinib for PFS in the overall patient population, no significant difference between the two was found in the subgroup of patients with CNS metastases. These results can serve as a foundation for basic, clinical, and translational research and guide clinical oncologists in developing individualized treatment strategies for patients with ALK-p, ALK inhibitor-naive advanced NSCLC.

Recent progress in targeted therapy for non-small cell lung cancer

The high morbidity and mortality of non-small cell lung cancer (NSCLC) have always been major threats to people's health. With the identification of carcinogenic drivers in non-small cell lung cancer and the clinical application of targeted drugs, the prognosis of non-small cell lung cancer patients has greatly improved. However, in a large number of non-small cell lung cancer cases, the carcinogenic driver is unknown. Identifying genetic alterations is critical for effective individualized therapy in NSCLC. Moreover, targeted drugs are difficult to apply in the clinic. Cancer drug resistance is an unavoidable obstacle limiting the efficacy and application of targeted drugs. This review describes the mechanisms of targeted-drug resistance and newly identified non-small cell lung cancer targets (e.g., KRAS G12C, NGRs, DDRs, CLIP1-LTK, PELP1, STK11/LKB1, NFE2L2/KEAP1, RICTOR, PTEN, RASGRF1, LINE-1, and SphK1). Research into these mechanisms and targets will drive individualized treatment of non-small cell lung cancer to generate better outcomes.

CodeBreaK 200: Sotorasib (AMG510) Has Broken the KRAS G12C+ NSCLC Enigma Code

Per the US FDA sotorasib approval summary, KRAS G12C mutation is found in approximately 14% of adenocarcinoma of the lung, primarily in patients with a history of smoking. Until recently, targeted therapies against KRAS G12C have been largely unsuccessful due to the small protein size of KRAS and thus lack of binding pockets in KRAS and rapid hydrolysis of GTP to GDP by KRAS enzymes from abundance of GTP in the cytoplasm. Sotorasib, a first-in-class covalent KRAS G12C inhibitor that binds to the switch pocket II in the KRAS G12C-GDP "off" state, received US FDA accelerated approval on May 21, 2021 in the US, based on a Phase II dose expansion cohort of CodeBreaK 100 trial. Sotorasib at 960 mg once daily achieved an ORR of 36% (95% CI: 28%, 45%), with a median response duration of 10 months (range 1.3+, 11.1) in 124 KRAS G12C+ NSCLC. At the European Society of Medical Oncology (ESMO) 2022 annual meeting, sotorasib achieved a statistically significant improved PFS over docetaxel (HR = 0.66; 95% CI: 0. 51-0.86; P = 0.002). The modest magnitude of PFS improvement of 1.1 months (from 4.5 months to 5.6 months) and the ORR of 28% led to a vigorous debate on whether sotorasib was indeed a true breakthrough. In this pros and cons debate, we argue thatsotorasib has achieved a true breakthrough.

Efficacy of Brigatinib in Patients With Advanced ALK-Positive NSCLC Who Progressed on Alectinib or Ceritinib: ALK in Lung Cancer Trial of brigAtinib-2 (ALTA-2)

INTRODUCTION

Brigatinib is a potent next-generation ALK tyrosine kinase inhibitor approved for treatment-naive and crizotinib-refractory advanced ALK-positive (ALK+) NSCLC. We evaluated brigatinib after other next-generation ALK tyrosine kinase inhibitors.

METHODS

In this single-arm, phase 2, ALK in Lung Cancer Trial of brigAtinib-2 (NCT03535740), patients with advanced ALK+ NSCLC whose disease progressed on alectinib or ceritinib received brigatinib 180 mg once daily (after 7-d 90-mg lead-in). Primary end point was independent review committee (IRC)-assessed overall response rate (ORR). Circulating tumor DNA (ctDNA) was analyzed.

RESULTS

Among 103 patients (data cutoff: September 30, 2020; median follow-up [range]: 10.8 [0.5-17.7] mo), confirmed IRC-ORR was 26.2% (95% confidence interval [CI]: 18.0-35.8), median duration of response, 6.3 months (95% CI: 5.6-not reached), and median progression-free survival (mPFS), 3.8 months (95% CI: 3.5-5.8). mPFS was 1.9 months (95% CI: 1.8-3.7) in patients with ctDNA-detectable baseline ALK fusion (n = 64). Among 86 patients who progressed on alectinib, IRC-ORR was 29.1% (95% CI: 19.8-39.9); mPFS was 3.8 months (95% CI: 1.9-5.4). Resistance mutations were present in 33.3% (26 of 78) of baseline ctDNA; 54% (14 of 26) of mutations were G1202R; 52% (33 of 64) of patients with detectable ALK fusion had EML4-ALK variant 3. Most common all-grade treatment-related adverse events were increased creatine phosphokinase (32%) and diarrhea (27%). The mean dose intensity of brigatinib (180 mg once daily) was 85.9%.

CONCLUSIONS

In ALK in Lung Cancer Trial of brigAtinib-2, brigatinib was found to have a limited activity in patients with ALK+ NSCLC post-ceritinib or post-alectinib therapy. mPFS was longer with brigatinib in patients without baseline detectable plasma ALK fusion.

Classical ALK G1202R resistance mutation was identified in a lung adenocarcinoma patient with rare LOC388942-ALK fusion after sequential treatment with ALK-TKIs and anlotinib: a case report

BACKGROUND

Anaplastic lymphoma kinase (ALK)-positive non-small cell lung cancer (NSCLC) is a heterogeneous disease. To date, more than ninety ALK fusions in lung cancer have been found. Here, we report for the first time a rare LOC388942-ALK fusion in NSCLC was sensitive to crizotinib but resistant to the sequential ceritinib and alectinib and acquired classical ALK G1202R resistance mutation after long-term treatment with anlotinib. This case highlights dynamic monitoring of gene alteration using next-generation sequencing (NGS) is necessary during the anti-tumor process.

CASE DESCRIPTION

A 55-year-old male, with no history of smoking history and no family history of cancer, was found malignant pleural effusion and multiple metastasis nodules in the left lung. He was histopathologically diagnosed with ALK-positive cT4N0M1a adenocarcinoma in June 2016. NGS of the tumor identified a rare LOC388942-ALK fusion (L intergenic: A 20, 1.41%). Then, the patient was treated with chemotherapy, crizotinib, ceritinib, alectinib, and anlotinib sequentially. The patient achieved partial response (PR) to chemotherapy and crizotinib. No evidence of a secondary resistant molecular event was found after resistance to crizotinib, ceritinib, or Alectinib. After 8 months of alectinib treatment, the tumor gradually enlarged again. Anlotinib was followed for 13 months. Thirteen months later, new lesions in the lower lobe of the right lung appeared and increased gradually, indicating definite progression of the tumor. Classical ALK G1202R resistance mutations was detected using cfDNA NGS. The patient refused to receive lorlatinib targeting G1202R resistance mutations and continued with anlotinib. He dead in August 2022, achieving 5-year overall survival (OS).

CONCLUSIONS

Distinct ALK fusions in NSCLC have different cancer biology, leading to different response to ALK tyrosine kinase inhibitors (ALK-TKIs), even developed different resistance mechanism. Reporting the clinical details of rare ALK fusions in NSCLC is necessary to guide the treatment for clinicians and researchers.

Lorlatinib and compound mutations in ALK+ large-cell neuroendocrine lung carcinoma: a case report

Large-cell neuroendocrine lung carcinoma (LCNEC) is a high-grade neoplasm with median survival of 1 year and limited therapeutic options. Here, we report the unusual case of a 47-yr-old female smoker with stage IV LCNEC featuring EML4-ALK variant 2 (E20:A20), wild-type TP53/RB1, and low tumor mutational burden of 3.91 mut/Mb. Despite early progression within 3 mo under crizotinib, a durable response was achieved with alectinib. Oligoprogression in the left breast 10 mo later was treated by surgery, followed by a switch to ceritinib upon multifocal progression and detection of ALK:p.V1180L in the mastectomy specimen, but without success. Another rebiopsy revealed ALK:p.L1196M, but the tumor did not respond to brigatinib or carboplatin/pemetrexed, before stabilization under lorlatinib. Diffuse progression 8 mo later with detection of ALK :p.L1196M/p.G1202R and p.L1196M/ p.D1203N evolving from the previous p.L1196M did not respond to chemoimmunotherapy, and the patient succumbed with an overall survival (OS) of 37 mo. This case illustrates the importance of molecular profiling for LCNEC regardless of smoking status, and the superiority of next-generation ALK inhibitors compared to crizotinib for ALK+ cases. Lorlatinib retained efficacy in the heavily pretreated setting, whereas its upfront use could possibly have prevented the stepwise emergence of compound ALK mutations. Furthermore, the disease course was more aggressive and OS shorter compared to the V2/TP53wt ALK+ lung adenocarcinoma, whereas crizotinib, ceritinib, and brigatinib did not confer the benefit expected according to next-generation sequencing results, which also underline the need for more potent drugs against ALK in the high-risk setting of neuroendocrine histology.

Current Landscape of Therapeutic Resistance in Lung Cancer and Promising Strategies to Overcome Resistance

Lung cancer is one of the leading causes of cancer-related deaths worldwide with a 5-year survival rate of less than 18%. Current treatment modalities include surgery, chemotherapy, radiation therapy, targeted therapy, and immunotherapy. Despite advances in therapeutic options, resistance to therapy remains a major obstacle to the effectiveness of long-term treatment, eventually leading to therapeutic insensitivity, poor progression-free survival, and disease relapse. Resistance mechanisms stem from genetic mutations and/or epigenetic changes, unregulated drug efflux, tumor hypoxia, alterations in the tumor microenvironment, and several other cellular and molecular alterations. A better understanding of these mechanisms is crucial for targeting factors involved in therapeutic resistance, establishing novel antitumor targets, and developing therapeutic strategies to resensitize cancer cells towards treatment. In this review, we summarize diverse mechanisms driving resistance to chemotherapy, radiotherapy, targeted therapy, and immunotherapy, and promising strategies to help overcome this therapeutic resistance.

The quantum leap in therapeutics for advanced ALK+ non-small cell lung cancer and pursuit to cure with precision medicine

Since the discovery 15 years ago, we have seen a quantum leap in the treatment and survival for individuals diagnosed with ALK+ lung cancers. Unfortunately however, for most, the diagnosis is made in an incurable circumstance given the late presentation of symptoms. Through a revolutionary wave of therapeutics, individuals may remarkably live over a decade, however many fall short of this milestone, as the molecular profile of this disease is very heterogeneous, reflected in variable survival outcomes. Despite a significant improval in survival and quality of life with ALK-inhibitor monotherapies, now available across multiple-generations, drug resistance and disease relapse remains inevitable, and treatment is offered in an empiric, stepwise, non personalised biomarker informed fashion. A proposed future focus to treating ALK to improve the chronicity of this disease and even promote cure, is to deliver a personalised dynamic approach to care, with rational combinations of drugs in conjunction with local ablative therapies to prevent and constantly proactively alter clonal selection. Such an approach would be informed by precision imaging with MRI-brain and FDG-PETs sequentially, and by regular plasma sampling including for circulating tumour DNA sequencing with personalised therapeutic switches occurring prior to the emergence of radiological and clinical relapse. Such an approach to care will require a complete paradigm shift in the way we approach the treatment of advanced cancer, however evidence to date in ALK+ lung cancers, support this new frontier of investigation.

Review of Therapeutic Strategies for Anaplastic Lymphoma Kinase-Rearranged Non-Small Cell Lung Cancer

Simple Summary

Anaplastic lymphoma kinase (ALK)-rearranged non-small cell lung cancer (NSCLC) was first reported in 2007. Following the development of crizotinib as a tyrosine kinase inhibitor (TKI) targeting ALK, the treatment of advanced NSCLC with ALK-rearrangements has made remarkable progress. Currently, there are five ALK-TKIs approved by the FDA, and the development of new agents, including fourth-generation TKI, is ongoing. Clinical trials with angiogenesis inhibitors and immune checkpoint inhibitors are also underway, and further progress in the treatment of ALK-rearranged advanced NSCLC is expected. The purpose of this manuscript is to provide information on the recent clinical trials of ALK-TKIs, angiogenesis inhibitors, immune checkpoint inhibitors, and chemotherapy, to describe tissue and liquid biopsy as a method to investigate the mechanisms of resistance against ALK-TKIs and suggest a proposed treatment algorithm.

Abstract

Non-small cell lung cancer (NSCLC) with anaplastic lymphoma kinase rearrangement (ALK) was first reported in 2007. ALK-rearranged NSCLC accounts for about 3–8% of NSCLC. The first-line therapy for ALK-rearranged advanced NSCLC is tyrosine kinase inhibitors (TKI) targeting ALK. Following the development of crizotinib, the first ALK-TKI, patient prognosis has been greatly improved. Currently, five TKIs are approved by the FDA. In addition, clinical trials of the novel TKI, ensartinib, and fourth-generation ALK-TKI for compound ALK mutation are ongoing. Treatment with angiogenesis inhibitors and immune checkpoint inhibitors is also being studied. However, as the disease progresses, cancers tend to develop resistance mechanisms. In addition to ALK mutations, other mechanisms, including the activation of bypass signaling pathways and histological transformation, cause resistance, and the identification of these mechanisms is important in selecting subsequent therapy. Studies on tissue and liquid biopsy have been reported and are expected to be useful tools for identifying resistance mechanisms. The purpose of this manuscript is to provide information on the recent clinical trials of ALK-TKIs, angiogenesis inhibitors, immune checkpoint inhibitors, and chemotherapy to describe tissue and liquid biopsy as a method to investigate the mechanisms of resistance against ALK-TKIs and suggest a proposed treatment algorithm.

Deep RNA Sequencing Revealed Fusion Junctional Heterogeneity May Predict Crizotinib Treatment Efficacy in ALK-Rearranged NSCLC

INTRODUCTION

Gene fusion variants in ALK-rearranged NSCLC may predict patient outcomes, but previous results have been inconclusive. Fusion isoforms coexisting in the same tumor may affect the efficacy of targeted therapy, but they have not been investigated.

METHODS

Patients with ALK-rearranged NSCLC who received crizotinib treatments were recruited. Precrizotinib tumor tissues were analyzed by the anchored multiplex polymerase chain reaction for targeted RNA sequencing. Kaplan-Meier and Cox regression were used to compare overall and progression-free survivals.

RESULTS

Of the 51 studied subjects, EML4-ALK variant types v1, v2, v3, and others were detected in 23 (45.1%), five (9.8%), 19 (37.3%), and four patients (7.8%), respectively. Multiple EML4-ALK RNA isoforms were detected in 24 tumors (47.1%), and single isoform in 27 (52.9%). Most of the v3 tumors (16 of 19) harbored both v3a and v3b RNA isoforms. Multiple isoforms were also detected in eight non-v3 tumors (33.3% of all 24 multiple isoforms; five v1, two v5', and one v2). Compared with patients with single isoform, those with multiple isoforms had worse progression-free (hazard ratio and 95% confidence interval: 2.45 [1.06-5.69]) and overall (hazard ratio [95% confidence interval]: 3.74 [1.26-11.13]) survivals after adjusting for potential confounders including variant type. Using the patient-derived H2228 cells known to express v3a and v3b, our single-cell polymerase chain reaction detected either v3a or v3b in most single cells. Treatment of H2228 cells by three ALK inhibitors revealed increased ratios of v3a-to-v3b expression over time.

CONCLUSIONS

Intratumoral EML4-ALK isoforms may predict the efficacy of targeted therapy in ALK-rearranged NSCLC. Temporal changes of intratumoral fusion isoforms may result from differential selection pressures that a drug might have on one isoform over another. Larger studies on fusion heterogeneity using RNA sequencing are warranted.