Evolution in the treatment landscape of non-small cell lung cancer with ALK gene alterations: from the first- to third-generation of ALK inhibitors

ABSTRACT

Introduction: The medical treatment of non-small cell lung cancer (NSCLC) has radically changed over the last 10 years thanks to new molecular-targeted drugs able to act on biological mechanisms involved in tumor development. One such mechanism is the aberrant anaplastic lymphoma kinase (ALK) activation: patients with ALK-driven NSCLC benefit from treatments that selectively inhibit its pathogenetic mechanism.

Areas covered: The first-generation ALK inhibitor is crizotinib, initially used in Europe as second-line treatment for ALK-positive metastatic NSCLC patients, then approved as the standard first-line (already approved in the USA as front-line therapy). However, most patients eventually experience disease progression due to the emergence of secondary resistance, partly linked to ALK-dependent mechanisms, hence the development of second- and third-generation ALK inhibitors: ceritinib, alectinib, and brigatinib are approved for ALK-positive NSCLC, lorlatinib is currently being evaluated while others are under development.

Expert opinion: Despite the considerable responses to these new inhibitors, however, resistance mechanisms are described. Thus, while the therapeutic scenario of NSCLC has been soon revolutionized introducing next-generation ALK inhibitors in the first-line setting, future research should identify combined therapies or new generation drugs overcoming resistance in pretreated patients.     

Targeting epidermal growth factor receptor in the treatment of non-small-cell lung cancer

Importance of the field: The management of non-small-cell lung cancer (NSCLC) has undergone a paradigm shift in the last decade, with the survival advantage demonstrated by the incorporation of anti-epidermal growth factor receptor (EGFR) agents to the standard treatment of advanced/metastatic NSCLC.

Areas covered in this review: We review the existing data regarding the distinct anti-EGFR agents in the NSCLC treatment and the potential role of the investigated biomarkers in the clinical outcome.

What the reader will gain: Tyrosine kinase inhibitors have been used in first-line, second-line and more settings with extremely good results in a subgroup of patients. Cetuximab remains the only anti-EGFR monoclonal antibody to show survival benefit when combined with a cytotoxic agent in the front-line setting. Anti-EGFR treatment is associated with a dramatic clinical benefit in a subgroup of patients, emphasizing the importance of customizing treatment. Several biomarkers have been investigated for their predictive or prognostic value. Validation of identification of biomarkers remains a focus of intense research that may ultimately guide therapeutic decision making, as none of these is considered ideal to discriminate responding from non-responding patients. However, the current evidence of the EGFR mutation analysis from a recent randomised trial suggests that EGFR mutation analysis is quite a good predictive marker for responsiveness to anti-EGFR TKIs. Moreover, the identification of surrogate markers to indicate optimal activity of the anti-EGFR agent is also needed. This review article provides data from large clinical trials using anti-EGFR agents and correlates these results with the tested biomarkers.

Take home message: EGFR inhibition has shown very encouraging results and has improved the outcome of the NSCLC treatment. However, a plateau of significant clinical benefit seems to have been reached and we believe that the time to move away from the traditional treatment approach to more individualizing therapies has come.     

Emerging treatment for ALK-positive lung cancer

Introduction: Lung cancer is associated with poor prognosis and limited benefit from chemotherapy. The treatment of non-small cell lung cancer (NSCLC) has been revolutionized by the discovery of targetable genetic alterations, including the ALK fusion oncogene.

Areas covered: Three drugs have been approved for clinical use in ALK-positive patients – crizotinib, ceritinib and alectinib. Unfortunately, treatment resistance inevitably develops. Several mechanisms of acquired resistance are reported. In this review, we will discuss emerging treatment options in ALK-positive advanced NSCLC and strategies to overcome resistance mechanisms, including newer generation of ALK inhibitors, Hsp90 inhibitors and immunotherapy.

Expert opinion: Tremendous advances have been made in the treatment of ALK-positive lung cancers, but management hurdles still exist, including universal development of resistance to ALK inhibitors and limited CNS activity. Given that specific treatment strategies target distinct patterns of resistance, re-biopsy at the time of progression appears necessary to optimize management. However, there remain many issues in routine clinical application including the burden placed on the patients by serial biopsies and the risks of repeat invasive procedures. Future studies are needed to validate the usage of non- or minimally invasive tests and to determine the optimal orders of utilizing different ALK inhibitors.     

MEK inhibitors under development for treatment of non-small-cell lung cancer

Introduction: The mitogen-activated protein kinase (MAPK) pathway is intimately implicated in the molecular pathogenesis of non-small-cell lung cancer (NSCLC). Aberrant MAPK signaling resulting from the upstream activating mutations converges on mitogen-activated protein kinase kinase 1/2 (MEK1/2), making MEK inhibition an attractive strategy for the treatment of NSCLC. Several MEK inhibitors have demonstrated anticancer activity in patients with NSCLC.

Areas covered: In this article, we discuss the biological rationale for the use of MEK inhibitors and summarize the clinical experience with MEK1/2 inhibitors for the treatment of NSCLC, from initial phase I studies to phase II/III studies, both as monotherapy or in combination with other anticancer agents.

Expert opinion: Trametinib in combination with the BRAF inhibitor dabrafenib represents the first MEK1/2 inhibitor containing regimen that is approved for advanced BRAF^V600E-mutant NSCLC. Other MEK1/2 inhibitors that are also in advanced stages of clinical development include selumetinib, cobimetinib, and binimetinib. Several studies of MEK inhibitor combination therapies are underway, including trials using combined MEK inhibition and immune checkpoint blockade. Further research aimed at discovering biomarkers of response and resistance to MEK1/2 inhibitors will be needed to develop rational combination strategies for the treatment of NSCLC driven by aberrant MAPK signaling.     

C-MET inhibitors for advanced non-small cell lung cancer

Introduction: The role of the c-mesenchymal-epithelial transition factor (c-MET) signaling pathway in tumor progression and invasion has been extensively studied. C-MET inhibitors have shown anti-tumor activity in NSCLC both in preclinical and in clinical trials. However, given the molecular heterogeneity of NSCLC, it is likely that only a specific subset of NSCLC patients will benefit from c-MET inhibitors. Emerging data also suggest that MET inhibitors in combination with EGFR-TKIs (epidermal growth factor receptor tyrosine kinase inhibitors) may have a role in therapy for both EGFR-TKI resistant and EGFR-TKI naïve patients. The challenges ahead are in the identification of the molecular subtypes that benefit most.

Areas covered: This review summarizes the current understanding of c-MET biology in relation to studies evaluating c-MET inhibitors in the treatment of NSCLC.

Expert opinion: MET inhibitors have the potential to benefit subsets of NSCLC patients with specific genetic alterations. Exon-14 skipping mutations appear so far to be the most promising molecular subset that is sensitive to MET inhibitors, whereas overexpression, amplification and point mutations of MET seem more challenging subgroups to target. Combination with other target agents, such as EGFR inhibitors, may represent a promising therapeutic strategy in specific areas (e.g. EGFR-TKI resistance).     

Is there a role for dacomitinib,a second-generation irreversible inhibitor of the epidermal-growth factor receptor tyrosine kinase,in advanced non-small cell lung cancer?

ABSTRACT

Introduction

Non-small cell lung cancer (NSCLC) is a highly lethal disease. During the past 20 years, the epidermal growth factor receptor (EGFR) has been a relevant target for anticancer drug-design, and a large family of EGFR tyrosine kinase inhibitors (TKI) were designed, which improved therapeutic outcomes compared to conventional chemotherapy in NSCLC patients with specific EGFR mutations. However, resistance to these inhibitors occurs; therefore, the debate on which inhibitor should be used first is still open. Dacomitinib was approved in 2018 for the first-line treatment of NSCLC with EGFR activating mutations.     

Tubulin inhibitors in non-small cell lung cancer: looking back and forward

Introduction: Although the advent of target therapy for lung cancer has brought about outstanding results, this benefit is confined to a subgroup of molecularly selected patients, whereas for most non-small cell lung cancer (NSCLC) patients, chemotherapy still represents the milestone of treatment. Since their introduction into clinics, microtubule targeting agents (MTA), including vinca alkaloids and taxanes, have been extensively used for NSCLC in different settings and combinations.

Areas Covered: In this review, MTA are classified according to their mechanism of action, with a focus on the most common mechanisms of resistance. Moreover, an overview of the most remarkable clinical data regarding MTA in adjuvant, neoadjuvant and advanced setting is provided. Finally, the novel mitotic kinases inhibitors are described according to their different mechanism of action and clinical activity compared to MTA.

Expert Opinion: Unfortunately, the awaited benefit deriving from the actually available chemotherapeutic regimens for advanced NSCLC has reached a plateau. In this scenario, the identification of reliable predictive biomarkers represents a major challenge. Moreover, different schedules for MTA administration are currently under investigation, such as the combination of MTA with other drugs able to bypass the resistance derived from the ‘mitotic slippage’ and the use of metronomic administration of spindle poisons with anti-angiogenic or immunomodulatory agents.     

Emerging treatment using tubulin inhibitors in advanced non-small cell lung cancer

Introduction: Tubulin inhibitors including taxanes and vinca alkaloids are important components of chemotherapy regimens used in advanced non-small cell lung cancer (NSCLC). Despite a treatment paradigm shift due to molecularly-targeted therapies and immunotherapy, a majority of patients will receive chemotherapy during their treatment course. Either used alone or in combination, tubulin inhibitors have demonstrated clinical benefits in different settings of lung cancer management.

Areas covered: This review first discusses FDA-approved tubulin inhibitors for NSCLC, such as paclitaxel, docetaxel, vinorelbine, and nab-paclitaxel. The article then provides a summary of novel tubulin inhibitors, including cabazitaxel, eribulin, ixabepilone, patupilone, plinabulin, new colchicine analogues and others. It also discusses new tubulin inhibitor combinations with immunotherapy (PD-1/PD-L1 inhibitors) and molecularly-targeted therapies (e.g. anti-angiogenic agents, mTOR inhibitors, heat shock protein 90 inhibitors, MEK inhibitors, and anti-HER3 agents). Lastly, emerging data on potential resistance mechanisms and predictive biomarkers for tubulin inhibitors are explored.

Expert opinion: Tubulin inhibitors will likely continue to play important roles in NSCLC management due to the advent of novel agents and combinations. Through further understanding of tumor biology, investigation of drug resistance, and development of predictive biomarkers, we will be better positioned to incorporate microtubule inhibition into patient specific treatment strategies.     

cMET in triple-negative breast cancer: is it a therapeutic target for this subset of breast cancer patients?

Introduction: The identification and validation of a targeted therapy for triple-negative breast cancer (TNBC) is currently one of the most urgent needs in breast cancer therapeutics. The cMET oncogene encodes a membrane-bound tyrosine kinase implicated in the formation and/or progression of several cancer types, including TNBC. Currently, inhibitors targeting cMET are undergoing clinical trials for a variety of cancers, including TNBC. These include anti-cMET and anti-hepatocyte growth factor (HGF) monoclonal antibodies and tyrosine kinase inhibitors.

Areas covered: This article reviews the structure and mode of action of cMET, the role of cMET in cancer formation/development, with particular emphasis on its role in basal/TNBC and its potential as a therapeutic target for this subtype of breast cancer.

Expert opinion: Due to cancer heterogeneity, it is unlikely that all TNBC patients will be responsive to anti-cMET drugs. Therefore, if cMET is to be used as a target for treatment, it will be important to identify predictive biomarkers to select, upfront, those patients likely to benefit. Potential predictive biomarkers for anti-cMET treatments in basal/TNBC include cMET, phospho-cMET, downstream signaling proteins or HGF. These putative predictive biomarkers should be evaluated in a large panel of basal/TNBC cell lines before incorporation into clinical trials involving anti-cMET drugs.     

Investigational multitargeted kinase inhibitors in development for head and neck neoplasms

Introduction: Despite advances in treatment, head and neck squamous cell carcinoma (HNSCC) survival rates remain stagnant. Current treatment is associated with significant toxicities and includes chemotherapy, radiation, surgery, and few targeted treatments. Targeted treatments, epidermal growth factor receptor (EGFR)-targeted agent, cetuximab, and immune checkpoint inhibitors, pembrolizumab and nivolumab, show improved toxicity profiles and modestly improved survival in select patients. An urgent need remains to identify novel targeted treatments for single-agent or combined therapy use.

Areas covered: Multitargeted kinase inhibitors are small molecule inhibitors with limited toxicity. This review will focus on early-stage investigations of multitargeted tyrosine kinase inhibitors (m-TKIs) (those that target at least two tyrosine kinases) for HNSCC. Preclinical and early trials investigating m-TKIs for various disease settings of HNSCC will be evaluated for efficacy, identification of significant biomarkers and potential for combination therapy.

Expert opinion: Few single agent m-TKIs have demonstrated efficacy in unselected HNSCC populations. The most promising clinical results have been obtained when m-TKIs are tested in combination with other therapies, including immunotherapy, or in mutation-defined subgroups of patients. The future success of m-TKIs will rely on identification, in preclinical models and clinical trials, of predictive biomarkers of response and mechanisms of innate and acquired resistance.     

New systemic strategies for overcoming resistance to targeted therapies in non-small cell lung cancer

Introduction: Although the achievements in the treatment of advanced non-small cell lung cancer (NSCLC) have been translated in improved disease control, response rate and survival, especially in the case of patients with targetable oncogenic drivers, acquired resistance is common after initial benefit; furthermore, primary resistance can occasionally be observed. Due to its clinical implications, the management of treatment-resistant NSCLC is a top topic of the current research, and many efforts are being put in the study of the mechanisms at the base of resistance and in the development of effective therapeutic countermeasures.

Areas covered: This review aims at identifying the most relevant novel chemical therapies designed to overcome resistance in NSCLC, including recently approved agents, as well as compounds in clinical development.

Expert opinion: An improved knowledge of the mechanisms causing resistance to treatments in NSCLC translates into effective innovative chemical therapies able to overcome such occurrence, and the paradigms of this progress are represented by novel inhibitors of the epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase (ALK); however, the study of novel systemic therapies in this setting is challenging, and further efforts in this setting are highly needed.     

Reviewing the safety of erlotinib in non-small cell lung cancer

Importance of the field: Erlotinib, a potent inhibitor of EGFR activity, is approved as a monotherapy for the treatment of advanced NSCLC and in combination with gemcitabine for advanced pancreatic cancer. The oral administration and manageable toxicity of erlotinib, along with its similar efficacy to chemotherapy, make it an important option as either maintenance therapy or in second-/third-line for patients with NSCLC who have previously received first-line chemotherapy. It is also an emerging option in other treatment settings in NSCLC.

Areas covered in this review: This review summarizes safety data from major clinical trials of erlotinib in patients with advanced NSCLC, as well as post-marketing data obtained in the 5 years since this drug was first approved.

What the reader will gain: An understanding of the common toxicities expected with erlotinib in patients with advanced NSCLC.

Take home message: Erlotinib is a well-tolerated treatment option for patients with advanced NSCLC. The main adverse events of rash and diarrhea are typically mild or moderate in severity, and rarely lead to treatment withdrawal. When necessary, rash and diarrhea can be easily managed prophylactically, by active intervention or through dose reduction.     

Pharmacogenetic considerations in the treatment of psychiatric disorders

Importance of the field: Despite continued efforts to optimize pharmacological treatment for individuals with psychiatric disorders, efficacy and tolerability of medication remains highly variable. In addition to clinical heterogeneity, diagnostic uncertainty, environmental, social factors, and genetic factors have been identified as playing an important role in the interindividual differences in therapeutic and toxic drug effects.

Areas covered in this review: This article describes recent developments in the field of psychiatric pharmacogenetics and focuses on antidepressant, antipsychotic, anticonvulsant, and mood-stabilizing drugs.

What the reader will gain: Recent findings from pharmacogenetic clinical trials are reviewed and clinical implications are discussed.

Take home message: Although current data are too sparse to allow the development of guidelines for using pharmacogenetic testing in routine clinical practice, the field of psychiatric pharmacogenetics is rapidly developing and identification of genetic biomarkers that predict therapeutic response and risk of side effects will ultimately help the practitioner to choose effective and safe treatment for patients suffering from psychiatric disorders.     

An evaluation of brigatinib as a promising treatment option for non-small cell lung cancer

ABSTRACT

Introduction: Brigatinib is a second-line inhibitor for the treatment of rearranged anaplastic lymphoma kinase (ALK) in lung cancer patients which has significant activity against brain metastases. This tyrosine kinase inhibitor (TKI) overcomes a wide range of ALK mutations which confer therapeutic resistance and is increasingly applied in first-line therapy due to improved benefit for patients compared to crizotinib, the current standard of care.

Areas covered: The authors review the development and characteristics of brigatinib and discuss the optimal clinical use and sequence of the application of ALK inhibitors in patients progressing under therapy.

Expert opinion: ALK-rearranged NSCLC can be treated with a broad range of approved and novel inhibitors at various stages of therapy, including the second-line therapeutic brigatinib. Besides this TKI, the second-line ALK inhibitors alectinib and ceritinib, as well as the third-line lorlatinib are approved for the treatment of ALK-positive NSCLC patients. The main challenge is to find sequences and combinations of ALK inhibitors which provide the best benefit for the patients.     

Efficacy of crizotinib in first-line treatment of adults with ALK-positive advanced NSCLC

Introduction: The treatment of advanced non-small cell lung cancer (NSCLC) has evolved from palliative cytotoxic chemotherapy to precise medicine based on genetic alternations over the last decade. Anaplastic lymphoma kinase (ALK) rearrangement characterizes a molecular subset of NSCLC with an impressive response to crizotinib.

Areas covered: To analyze the efficacy of crizotinib in first-line treatment of adults with advanced ALK-positive NSCLC, updated data on development and recent advances of first-line crizotinib in this subset population are reviewed.

Expert opinion: To date, crizotinib should be established as a standard of care in previously untreated advanced NSCLC with ALK-rearrangement. However, the efficacy of first-line crizotinib is limited by acquired resistance. Second generation ALK inhibitors have demonstrated clinical activity in both crizotinib-refractory and crizotinib naïve setting. How to maximize first-line benefit for advanced ALK-positive NSCLC remains challenging. Combinational strategy, advances in companion diagnostics and optimization of ALK inhibitors might contribute to improve outcome in this subset of patients in future.     

New drugs in advanced non-small-cell lung cancer: searching for the correct clinical development

Importance of the field: Non-small-cell lung cancer (NSCLC) is one of the most active fields of research in oncology, with many drugs under clinical development. Most of these drugs offer novel mechanisms of action compared with drugs currently used in clinical practice.

Areas covered in this review: In this article, results recently obtained with most promising new drugs for advanced NSCLC are briefly described.

What the reader will gain: Most of the new drugs are currently being tested without a biomarker-driven selection, due to inadequate knowledge of predictive factors. A few drugs are tested in biologically selected samples of NSCLC patients. The results obtained with crizotinib in patients with ALK gene rearrangement are a good example of the speed with which biological discoveries can be translated to clinical testing.

Take home message: Emerging clinical and molecular data demonstrate that NSCLC is a family of related but distinct diseases. Some drugs tested in unselected population will probably obtain an incremental benefit compared to the current standard, but this will not substantially change the unfavorable prognosis of NSCLC patients. By contrast, unprecedented and much more cost-effective results can be obtained when targeted agents are administered following appropriate biomarker-driven patient selection.     

Novel immunotherapy in the treatment of advanced non-small cell lung cancer

Introduction: Lung cancers remain the principal cause of death cancer-related worldwide with a poor survival rate at five years from diagnosis. In patients with NSCLC harboring specific genetic alterations the anti EGFR TKIs and the ALK TKIs have improved the response rate and the quality of life compared to standard platinum-based chemotherapy. New approaches possibly applicable at the major of patients are needed.

Areas covered: The discovery that the immune system plays a fundamental role in the fight against cancer. The cancer cells use mechanisms able to avoid the immune control has led to the development of drugs able to overcome this escape route. The best known checkpoint pathways are the CTLA-4 and PD-1/PD-L1; they suppress T-cell activity in different ways: CTLA-4 regulates T-cell activity at an early stage whereas PD-1 regulates later effector T-cell activity within tissue and tumors. The best characterized checkpoint inhibitors in advanced NSCLC setting are ipilimumab and tremelimumab, (anti-CTLA-4 antibodies), nivolumab and pembrolizumab (anti-PD-1 antibodies), atezolizumab and durvalumab (anti-PD-L1 antibodies). Nivolumab and pembrolizumab have received the FDA and EMA approval for the treatment of NSCLC in second-line setting.

Expert commentary: The role played by tumor microenvironment may be the next area of research to overcome the resistance at the checkpoint inhibitors as well as the identification of biomarkers to better select patients. In addition checkpoint inhibitors are investigate in combination with other agent involved in immune control with promising results in solid tumors.     

Developments in pharmacotherapy for treating metastatic non-small cell lung cancer

Introduction: Most patients with non-small cell lung (NSCLC), including squamous cell carcinoma, adenocarcinoma and large cell carcinoma, have advanced disease at diagnosis and systemic therapy is the standard-of-care. About 20% of Caucasian patients are affected by an oncogene-addicted advanced NSCLC for which correspondent inhibitors are available.

Areas covered: The main state-of-the-art synthetic anticancer drugs in the groups of chemotherapeutics, epidermal growth factor receptor and anaplastic lymphoma kinase tyrosine kinase inhibitors for NSCLC treatment, are reviewed and discussed from phase III randomized practice-changing trials onwards. A structured search of bibliographic databases for peer-reviewed research literature and of main meetings using a focused review question was undertaken.

Expert opinion: The survival of NSCLC patients is increasing, regardless of the presence or not of a specific target, due to the availability of new generation drugs. The continuous deep knowledge of the mechanisms of NSCLC development and the constant research into new drugs should lead to the discovery of new potential targets and the synthesis of corresponding inhibitors to improve the outcomes of each subgroup of patients in order to control the disease in a constantly growing percentage of patients.     

The safety and efficacy of pembrolizumab for the treatment of non-small cell lung cancer

ABSTRACT

Introduction: Lung cancer is the leading cancer-related cause of death worldwide. The introduction of immune checkpoint inhibitors (ICIs) for the treatment of lung cancer has significantly improved the outcome of these patients. Pembrolizumab, a monoclonal IgG4-kappa antibody against programmed-death-1 (PD-1) protein, nowadays represents a standard of care for NSCLC patients. Although it has a favorable toxicity profile, some immune-related adverse events (irAEs) can be life-threatening, therefore its knowledge may help to optimize the care of these patients.

Areas covered: The authors review data regarding the efficacy and safety of pembrolizumab from the most relevant clinical trials as well as toxicities reported in the clinical use. Special considerations of use in special populations will be noted. Finally, its toxicity profile will be compared with other ICIs used in NSCLC.

Expert opinion: In the scenario of NSCLC, pembrolizumab shows a favorable safety profile with less than 10% serious immune-related adverse events (irAEs) when used in monotherapy and without adding relevant extra-toxicity to chemotherapy when used in combination. Monotherapy with pembrolizumab is associated with better health-related quality of life than chemotherapy. Early recognition and appropriate treatment of irAEs is of prime importance as most are reversible if correctly managed. Rechallenge with pembrolizumab is frequently feasible.     

An update on first line therapies for metastatic breast cancer

Introduction: In recent years, outcomes of patients with metastatic breast cancer (MBC) have improved due to a greater understanding of the mechanisms of carcinogenesis in the development of newer molecularly targeted drugs, especially those as a front-line therapy. Remarkable improvements have been made in the treatment of hormone receptor positive (HR+) and Her2 positive MBC and currently targeted treatment strategies represent a valid first line treatment.

Areas covered: Herein, the authors provide an overview of the first-line pharmacotherapies currently available for the treatment of MBC and provide their expert perspectives on the area.

Expert opinion: Decisions on the first-line treatment of MBC should consider the clinical features of the disease, but also the biological mechanisms that regulate tumor cell growth. New and effective therapeutic agents have recently been introduced in the first-line therapy of MBC. However, to optimize the treatment of patients with metastatic disease, clinicians need biomarkers of resistance or sensitivity to targeted therapies. Efforts must also be made in developing strategies to personalize treatments of MBC patients and to identify those patients who might gain the most benefit from new treatment interventions, to save costs and limit toxicity.