Managing treatment–related adverse events associated with Alk inhibitors

Anaplastic lymphoma kinase (ALK) rearrangements have been identified as key oncogenic drivers in a small subset of non-small-cell lung cancers (nsclcs). Small-molecule Alk kinase inhibitors such as crizotinib have transformed the natural history of nsclc for this subgroup of patients. Because of the prevalence of nsclc, ALK-positive patients represent an important example of the paradigm for personalized medicine. Although Alk inhibitors such as crizotinib are well tolerated, there is a potential for adverse events to occur. Proactive monitoring, treatment, and education concerning those adverse events will help to optimize the therapeutic index of the drugs. The present review summarizes the management of treatment-related adverse events that can arise with Alk inhibitors such as crizotinib.     

Precision medicine against <Emphasis Type="Italic">ALK</Emphasis>-positive non-small cell lung cancer: beyond crizotinib

Anaplastic lymphoma kinase (ALK) rearrangements represent the molecular driver of a subset of non-small cell lung cancers (NSCLCs). Despite the initial response, virtually all ALK-positive patients develop an acquired resistance to the ALK inhibitor crizotinib, usually within 12 months. Several next-generation ALK inhibitors have been developed in order to overcome crizotinib limitation, providing an unprecedented survival for this subset of patients. The aim of this review to summarize the current knowledge on ALK tyrosine kinase inhibitors (TKIs) in the treatment of advanced ALK-positive NSCLC, focusing on the role of novel ALK inhibitors in this setting. In addition, we will discuss their role in the pharmacological management of ALK-positive brain metastasis. Next-generation ALK inhibitors showed an impressive clinical activity in ALK-positive NSCLC, also against the sanctuary site of CNS. Sequential therapy with ALK TKIs appears to be effective in patients who fail a first ALK TKI and translates in clinically meaningful benefit. However, these agents display different activity profiles against crizotinib resistance mutation; therefore re-genotyping the disease at progression in order to administer the right TKI to the right patient is going to be necessary to correctly tailor the treatment. To avoid repeated invasive procedure, noninvasive methods to detect and monitor ALK rearrangement are under clinical investigation.     

Role of STK11 in ALK-positive non-small cell lung cancer

Anaplastic lymphoma kinase (ALK) inhibitors have been shown to be effective in treating patients with ALK-positive non-small cell lung cancer (NSCLC), and crizotinib, ceritinib and alectinib have been approved as clinical first-line therapeutic agents. The availability of these inhibitors has also largely changed the treatment strategy for advanced ALK-positive NSCLC. However, patients still inevitably develop resistance to ALK inhibitors, leading to tumor recurrence or metastasis. The most critical issues that need to be addressed in the current treatment of ALK-positive NSCLC include the high cost of targeted inhibitors and the potential for increased toxicity and resistance to combination therapy. Recently, it has been suggested that the serine/threonine kinase 11 (STK11) mutation may serve as one of the biomarkers for immunotherapy in NSCLC. Therefore, the main purpose of this review was to summarize the role of STK11 in ALK-positive NSCLC. The present review also summarizes the treatment and drug resistance studies in ALK-positive NSCLC and the current status of STK11 research in NSCLC.     

Activity of Crizotinib (PF02341066), a Dual Mesenchymal-Epithelial Transition (MET) and Anaplastic Lymphoma Kinase (ALK) Inhibitor,in a Non-small Cell Lung Cancer Patient with De Novo MET Amplification

Crizotinib is a dual MET and ALK inhibitor. Currently, clinical development of crizotinib is focused primarily on ALK rearranged non-small cell lung cancer (NSCLC). Here we report an NSCLC patient with de novo MET amplification but no ALK rearrangement who achieved a rapid and durable response to crizotinib indicating is also a bona fide MET inhibitor.     

Cancers broncho-pulmonaires réarrangés pour ALK: comment assurer une tolérance optimale du crizotinib en pratique clinique?

Crizotinib (XALKORI^™, Pfizer) is a tyrosine kinase inhibitor of ALK, MET, and ROS1, which is currently approved for the second line treatment for ALK-rearranged lung cancer. This work from an expert group, based on the review of the data from the Profile studies, aims to provide practical elements in order to optimize the tolerability of crizotinib. Specific major or frequent side effects of crizotinib are discussed: visual disturbances, cardiac effects, elevated transaminases, and hypogonadism. In the routine practice, patients should be advised about visual disturbances, especially with regard to driving in low brightness. Digestive disorders related to crizotinib are exceptionally persistent or severe. Dietary measures and symptomatic treatments usually control these disorders. It is recommended to perform an electrocardiogram before introduction of crizotinib, to identify prolonged QT interval. Torsades de pointes may produce dizziness or syncope. Hypogonadism should be considered in case of fatigue, decreased libido, and even depression, taking into account that these symptoms may be related to cancer; testosterone serum level should be measured to identify patients that may be eligible to receive a supplementation. Monitoring of liver function tests, including transaminases and bilirubin, is necessary. To conclude, these practical elements are helpful to optimize treatment with crizotinib in patients with ALK-rearranged lung cancer; in the future, academic initiatives should be taken to study these aspects, based on the monitoring of large cohorts of patients treated with crizotinib.     

Successful Management of Crizotinib-Induced Neutropenia in a Patient with Anaplastic Lymphoma Kinase-Positive Non-Small Cell Lung Cancer: A Case Report

Crizotinib, the first clinically available inhibitor of anaplastic lymphoma kinase (ALK) gene rearrangement, is generally well tolerated. In contrast, neutropenia induced by crizotinib is a commonly reported grade 3 or 4 adverse event. In such cases, interruption and dose reduction of crizotinib might be necessary for some patients with severe neutropenia. However, information concerning clinical experience and management of severe neutropenia is currently limited. In this report, the successful management of crizotinib-induced neutropenia by dose reduction of crizotinib in a patient with ALK-positive non-small cell lung cancer is described.Key Words: Crizotinib, Anaplastic lymphoma kinase gene rearrangement, Neutropenia, Alectinib, Non-small cell lung cancer     

Crizotinib for the Treatment of ALK‐Rearranged Non‐Small Cell Lung Cancer: A Success Story to Usher in the Second Decade of Molecular Targeted Therapy in Oncology

Crizotinib, an ALK/MET/ROS1 inhibitor, was approved by the U.S. Food and Drug Administration for the treatment of anaplastic lymphoma kinase (ALK)‐rearranged non‐small cell lung cancer (NSCLC) in August 2011, merely 4 years after the first publication of ALK‐rearranged NSCLC. The crizotinib approval was accompanied by the simultaneous approval of an ALK companion diagnostic fluorescent in situ hybridization assay for the detection of ALK‐rearranged NSCLC. Crizotinib continued to be developed as an ALK and MET inhibitor in other tumor types driven by alteration in ALK and MET. Crizotinib has recently been shown to be an effective ROS1 inhibitor in ROS1‐rearranged NSCLC, with potential future clinical applications in ROS1‐rearranged tumors. Here we summarize the heterogeneity within the ALK‐ and ROS1‐rearranged molecular subtypes of NSCLC. We review the past and future clinical development of crizotinib for ALK‐rearranged NSCLC and the diagnostic assays to detect ALK‐rearranged NSCLC. We highlight how the success of crizotinib has changed the paradigm of future drug development for targeted therapies by targeting a molecular‐defined subtype of NSCLC despite its rarity and affected the practice of personalized medicine in oncology, emphasizing close collaboration between clinical oncologists, pathologists, and translational scientists.     

Targeting ALK: a promising strategy for the treatment of non-small cell lung cancer, non-Hodgkin’s lymphoma, and neuroblastoma

Anaplastic lymphoma kinase (ALK) is a tyrosine kinase receptor that affects a number of biological and biochemical functions through normal ligand-dependent signaling. It has oncogenic functions in a number of tumors including non-small cell lung cancer (NSCLC), anaplastic large cell lymphoma, and neuroblastoma when altered by translocation or amplification or mutation. On August 2011, a small molecule inhibitor against ALK, crizotinib, was approved for therapy against NSCLC with ALK translocations. As we determine the molecular heterogeneity of tumors, the potential of ALK as a relevant therapeutic target in a number of malignancies has become apparent. This review will discuss some of the tumor types with oncogenic ALK alterations. The activity and unique toxicities of crizotinib are described, along with potential mechanisms of resistance and new therapies beyond crizotinib.     

ALK Inhibitors: What Is the Best Way to Treat Patients With ALK+ Non–Small-Cell Lung Cancer?

Genetic insight into the pathogenesis of lung cancer has paved the way for a new era in its treatment. Recently, anaplastic lymphoma kinase (ALK) has been identified as exerting a potent transforming effect through genetic rearrangement in patients with lung cancer. Preclinical and single-arm phase I studies have shown that patients with ALK-rearranged non–small cell lung cancer (NSCLC) can be successfully treated with crizotinib. Furthermore, a phase III randomized study indicated that crizotinib is superior to standard chemotherapy in the treatment of patients with NSCLC harboring the ALK rearrangement who had received 1 previous platinum-based chemotherapy. Despite the excellent efficacy of crizotinib in patients with ALK-positive (ALK⁺) lung cancer, resistance mechanisms—such as secondary mutations in the ALK gene, the activation of other oncogenes, and so on—have been identified as conferring resistance to crizotinib. Second-generation ALK inhibitors, such as alectinib and ceritinib, have been shown to be effective not only in crizotinib-naive patients but also in those resistant to crizotinib. Therefore, although some agents specifically targeting ALK have been developed and their efficacy has been documented, how ALK inhibitors should be administered in the setting of ALK-rearranged NSCLC remains to be fully elucidated. Can second-generation ALK inhibitors replace crizotinib? Is crizotinib just a first-generation ALK inhibitor? Is the sequential use of crizotinib and second-generation ALK inhibitors the best method? In this article, we review the preclinical and clinical results regarding crizotinib and second-generation ALK inhibitors, as well as the resistance mechanisms, and discuss the best methods for treating patients with ALK⁺ NSCLC.     

Amphiregulin triggered epidermal growth factor receptor activation confers in vivo crizotinib‐resistance of EML4‐ALK lung cancer and circumvention by epidermal growth factor receptor inhibitors

Crizotinib, a first‐generation anaplastic lymphoma kinase (ALK) tyrosine‐kinase inhibitor, is known to be effective against echinoderm microtubule‐associated protein‐like 4 (EML4)‐ALK‐positive non‐small cell lung cancers. Nonetheless, the tumors subsequently become resistant to crizotinib and recur in almost every case. The mechanism of the acquired resistance needs to be deciphered. In this study, we established crizotinib‐resistant cells (A925LPE3‐CR) via long‐term administration of crizotinib to a mouse model of pleural carcinomatous effusions; this model involved implantation of the A925LPE3 cell line, which harbors the EML4‐ALK gene rearrangement. The resistant cells did not have the secondary ALK mutations frequently occurring in crizotinib‐resistant cells, and these cells were cross‐resistant to alectinib and ceritinib as well. In cell clone #2, which is one of the clones of A925LPE3‐CR, crizotinib sensitivity was restored via the inhibition of epidermal growth factor receptor (EGFR) by means of an EGFR tyrosine‐kinase inhibitor (erlotinib) or an anti‐EGFR antibody (cetuximab) in vitro and in the murine xenograft model. Cell clone #2 did not have an EGFR mutation, but the expression of amphiregulin (AREG), one of EGFR ligands, was significantly increased. A knockdown of AREG with small interfering RNAs restored the sensitivity to crizotinib. These data suggest that overexpression of EGFR ligands such as AREG can cause resistance to crizotinib, and that inhibition of EGFR signaling may be a promising strategy to overcome crizotinib resistance in EML4‐ALK lung cancer.     

Management of Central Nervous System Metastases in Patients With Advanced Anaplastic Lymphoma Kinase-Rearranged Non–Small-Cell Lung Cancer During Crizotinib Treatment

BackgroundCentral nervous system (CNS) progression is a common manifestation of acquired resistance to crizotinib in anaplastic lymphoma kinase (ALK)-rearranged non–small-cell lung cancer (NSCLC). However, an optimal tailored treatment approach has not been established in patients with CNS failure during crizotinib treatment.Patients and MethodsPatients with ALK-rearranged NSCLC with CNS progression during crizotinib treatment between January 2013 and December 2016 were included for analysis. Clinical data for different treatments after CNS failure during crizotinib treatment were retrospectively collected.ResultsAmong the 44 patients who had CNS progression during crizotinib treatment, 19, 15, 8, and 2 patients received crizotinib treatment beyond progressive disease (CBPD), a second ALK tyrosine kinase inhibitor (TKI), chemotherapy, and best supportive care, respectively. Post progression survival offered by treatment with a second ALK TKI was significantly more favorable than that of chemotherapy (P < .001) or CBPD (P = .045). In addition, patients who received sequential treatment with a second ALK TKI had significantly longer intracranial time to progression (IC-TTP) compared with those treated with chemotherapy (P < .01) or CBPD after radiotherapy (P = .003). In the 7 patients who received brigatinib, the median IC-TTP was 21.8 months (95% confidence interval, 11.7-32.0). The additional use of CNS radiotherapy in patients treated with a second ALK TKI showed no significance in terms of IC-TTP (P = .54).ConclusionAlthough CBPD is an option in patients with isolated CNS progression during crizotinib treatment, sequential treatment with a second ALK TKI, particularly brigatinib, might be preferable. The newly approved TKI, brigatinib, showed promise in the control of brain metastases, even without radiotherapy.     

Detection of ALK and KRAS Mutations in Circulating Tumor DNA of Patients With Advanced ALK-Positive NSCLC With Disease Progression During Crizotinib Treatment

BackgroundIn patients with anaplastic lymphoma kinase (ALK)-positive non–small-cell lung cancer (NSCLC), disease progression occurs after a median of 9 to 10 months of crizotinib treatment. Several mechanisms of resistance have been identified and include ALK mutations and amplification or the activation of bypassing signaling pathways. Rebiopsy in NSCLC patients represents a critical issue and the analysis of circulating cell-free DNA (cfDNA) has a promising role for the identification of resistance mechanisms.Patients and MethodsTwenty patients with advanced ALK-positive NSCLC were enrolled after disease progression during crizotinib treatment; cfDNA was analyzed using digital droplet polymerase chain reaction (BioRad, Hercules, CA) for ALK (p.L1196M, p.G1269A, and p.F1174L) and Kirsten rat sarcoma (KRAS) (codons 12 and 13) mutations.ResultsALK secondary mutations (p.L1196M, p.G1269A, and p.F1174L) were identified in 5 patients; 1 patient had 2 ALK mutations (p.L1196M and p.G1269A). Overall, 10 patients presented KRAS mutations (7 p.G12D, 2 p.G12V, and 1 p.G12C mutations, respectively). In 3 patients KRAS mutations were associated with ALK mutations. cfDNA was monitored during the treatment with second-generation ALK inhibitors and the amount of ALK as well as KRAS mutations decreased along with tumor regression.ConclusionALK and KRAS mutations are associated with acquired resistance to crizotinib in ALK-positive NSCLC. In particular, ALK acquired mutations can be detected in plasma and could represent a promising tumor marker for response monitoring.     

The accelerated path of ceritinib: Translating pre-clinical development into clinical efficacy

The discovery of anaplastic lymphoma kinase (ALK)-rearranged non–small-cell lung cancer (NSCLC) in 2007 led to the development and subsequent approval of the ALK inhibitor crizotinib in 2011. However, despite its clinical efficacy, resistance to crizotinib invariably develops. There is now a next generation of ALK inhibitors, including two that have been approved—ceritinib and alectinib—and others that are in development—brigatinib, lorlatinib and X-396. Ceritinib and the other next-generation ALK inhibitors are more potent than crizotinib and can overcome tumor cell resistance mechanisms. Ceritinib gained US Food and Drug Administration approval in 2014 following accelerated review for the treatment of patients with ALK-positive (ALK+) metastatic NSCLC who have progressed on or are intolerant to crizotinib. In pre-clinical studies, it demonstrated more potent inhibition of ALK than crizotinib in enzymatic assays, more durable responses in xenograft models and the ability to potently overcome crizotinib resistance mutations in vitro (including the gatekeeper mutation). There is also evidence for ceritinib penetration across the blood-brain barrier. In clinical trials, ceritinib has demonstrated durable responses and progression-free survival in ALK-inhibitor–pre-treated and –naïve NSCLC patients, including high overall and intracranial response rates in those with central nervous system metastases. Selective gastrointestinal toxicity of ceritinib, such as diarrhea, nausea and vomiting is generally manageable with prophylactic medication and prompt dose reduction or interruption. Future progress in treating ALK+ NSCLC will focus on determining the optimal sequencing of therapies and strategies to overcome acquired resistance, an ongoing challenge in treating ALK-mutation–driven tumors.     

Phase 1/2 Study of the Safety and Tolerability of Nivolumab Plus Crizotinib for the First-Line Treatment of Anaplastic Lymphoma Kinase Translocation — Positive Advanced Non–Small Cell Lung Cancer (CheckMate 370)

Introduction

Crizotinib, an anaplastic lymphoma kinase (ALK) inhibitor, is a first-line treatment for ALK translocation–positive advanced non–small cell lung cancer (NSCLC); however, patients eventually progress. Immunotherapies, including the programmed death-1 inhibitor nivolumab, have resulted in durable responses and long-term overall survival in patients with NSCLC. We hypothesized that combining targeted therapy with immunotherapy could result in more patients with responses and/or more durable responses. Herein we report data from a study assessing nivolumab plus crizotinib in patients with previously untreated advanced ALK translocation–positive NSCLC.

Testing for anaplastic lymphoma kinase rearrangement to target crizotinib therapy: oncology,pathology and health economic perspectives

Crizotinib is a first-in-class oral anaplastic lymphoma kinase (ALK) inhibitor targeting ALK-rearranged non-small-cell lung cancer. The therapy was approved by the US FDA in August 2011 and received conditional marketing approval by the European Commission in October 2012 for advanced non-small-cell lung cancer. A break-apart FISH-based assay was jointly approved with crizotinib by the FDA. This assay and an immunohistochemistry assay that uses a D5F3 rabbit monoclonal primary antibody were also approved for marketing in Europe in October 2012. While ALK rearrangement has relatively low prevalence, a clinical benefit is exhibited in more than 85% of patients with median progression-free survival of 8–10 months. In this article, the authors summarize the therapy and alternative test strategies for identifying patients who are likely to respond to therapy, including key issues for effective and efficient testing. The key economic considerations regarding the joint companion diagnostic and therapy are also presented. Given the observed clinical benefit and relatively high cost of crizotinib therapy, companion diagnostics should be evaluated relative to response to therapy versus correlation alone whenever possible, and both high inter-rater reliability and external quality assessment programs are warranted.     

Successful Crizotinib Rechallenge after Crizotinib-Induced Organizing Pneumonia in Anaplastic Lymphoma Kinase-Rearranged Non-Small Cell Lung Cancer

Crizotinib, a first-line anaplastic lymphoma kinase (ALK)-tyrosine kinase inhibitor, has shown promising results for the treatment of locally advanced and metastatic lung cancer presenting the ALK rearrangement. On the other hand, secondary organizing pneumonia (OP) caused by anti-cancer drugs has been reported. While it is sometimes needed to rechallenge the suspected drug, the standard therapeutic strategy for secondary OP has not yet been established. We report a 60-year-old male with ALK-rearranged non-small cell lung cancer who developed crizotinib-induced OP and was successfully rechallenged with crizotinib. Six months after the rechallenge, the patient has achieved a partial response. To our knowledge, this is the first case in which crizotinib-induced OP has been successfully treated.Key Words: Lung cancer, Crizotinib, Organizing pneumonia, EML4-ALK     

Clinical benefit of continuing ALK inhibition with crizotinib beyond initial disease progression in patients with advanced ALK-positive NSCLC

BackgroundCrizotinib is approved to treat advanced ALK-positive non-small-cell lung cancer (NSCLC), but most patients ultimately develop progressive disease (PD). We investigated whether continuing ALK inhibition with crizotinib beyond PD (CBPD) is clinically beneficial and attempted to identify clinicopathologic characteristics associated with patients who experience clinical benefit.Patients and methodsPatients with advanced ALK-positive NSCLC enrolled in two ongoing multicenter, single-arm trials who developed RECIST-defined PD were allowed to continue crizotinib if they were deriving ongoing clinical benefit. In the present retrospective analysis, continuation of CBPD was defined as >3 weeks of crizotinib treatment after PD documentation. Patients who had PD as best response to initial crizotinib treatment were excluded. Baseline and post-progression characteristics, sites of PD, and overall survival (OS) were compared in patients who continued CBPD versus those who did not. The impact of continuing CBPD on OS after adjusting for potential confounding factors was assessed.ResultsAmong 194 crizotinib-treated patients with RECIST-defined PD, 120 (62%) continued CBPD. A significantly higher proportion of patients who continued CBPD than patients who did not had an ECOG performance status (PS) of 0/1 at PD (96% versus 82%; P = 0.02). CBPD patients had significantly longer OS from the time of PD [median 16.4 versus 3.9 months; hazards ratio (HR) 0.27, 95% confidence interval (CI): 0.17–0.42; P < 0.0001] and from the time of initial crizotinib treatment (median 29.6 versus 10.8 months; HR 0.30, 95% CI: 0.19–0.46; P < 0.0001). The multiple-covariate Cox regression analysis revealed that CBPD remained significantly associated with improved OS after adjusting for relevant factors.ConclusionsPatients who continued CBPD were more likely to have good ECOG PS (0/1) at the time of PD. Continuing ALK inhibition with crizotinib after PD may provide survival benefit to patients with advanced ALK-positive NSCLC.     

Establishment of a Conditional Transgenic Mouse Model Recapitulating EML4-ALK–Positive Human Non–Small Cell Lung Cancer

BackgroundAnaplastic lymphoma receptor tyrosine kinase gene (ALK) fusion is a distinct molecular subclassification of NSCLC that is targeted by anaplastic lymphoma kinase (ALK) inhibitors. We established a transgenic mouse model that expresses tumors highly resembling human NSCLC harboring echinoderm microtubule associated protein like 4 gene (EML)-ALK fusion. We aimed to test an EML4-ALK transgenic mouse model as a platform for assessing the efficacy of ALK inhibitors and examining mechanisms of acquired resistance to ALK inhibitors.MethodsTransgenic mouse lines harboring LoxP-STOP-LoxP-FLAGS–tagged human EML4-ALK (variant 1) transgene was established by using C57BL/6N mice. The transgenic mouse model with highly lung-specific, inducible expression of echinoderm microtubule associated protein like 4–ALK fusion protein was established by crossing the EML4-ALK transgenic mice with mice expressing Cre–estrogen receptor fusion protein under the control of surfactant protein C gene (SPC). Expression of EML4-ALK transgene was induced by intraperitoneally injecting mice with tamoxifen. When the lung tumor of the mice treated with the ALK inhibitor crizotinib for 2 weeks was measured, tumor shrinkage was observed.ResultsEML4-ALK tumor developed after 1 week of tamoxifen treatment. Echinoderm microtubule associated protein like 4–ALK was strongly expressed in the lung but not in other organs. ALK and FLAGS expressions were observed by immunohistochemistry. Treatment of EML4-ALK tumor–bearing mice with crizotinib for 2 weeks induced dramatic shrinkage of tumors with no signs of toxicity. Furthermore, prolonged treatment with crizotinib led to acquired resistance in tumors, resulting in regrowth and disease progression. The resistant tumor nodules revealed acquired ALK G1202R mutations.ConclusionsAn EML4-ALK transgenic mouse model for study of drug resistance was successfully established with short duration of tumorigenesis. This model should be a strong preclinical model for testing efficacy of ALK TKIs, providing a useful tool for investigating the mechanisms of acquired resistance and pursuing novel treatment strategies in ALK-positive lung cancer.     

Sequential Therapy with Crizotinib and Alectinib in ALK-Rearranged Non–Small Cell Lung Cancer—A Multicenter Retrospective Study

IntroductionAlectinib and crizotinib have been approved for the therapy of NSCLC caused by anaplastic lymphoma kinase gene (ALK) rearrangement. The effect of alectinib or crizotinib on overall survival (OS) in patients with ALK-rearranged NSCLC remains unknown.MethodsA multicenter retrospective study was conducted to compare OS between patients receiving alectinib and crizotinib and between patients treated with alectinib and those treated sequentially with crizotinib and then alectinib after crizotinib failure. The time to treatment failure (TTF), progression-free survival (PFS), and OS were compared.ResultsSixty-one patients with ALK-rearranged NSCLC were enrolled. Forty-six patients were treated with anaplastic lymphoma kinase (ALK) inhibitors (31 with crizotinib, 28 with alectinib, and 13 with both ALK inhibitors). The response rate was 66.7% for the crizotinib-treated group and 80.8% for the alectinib-treated group. Among all patients, TTF and PFS were significantly prolonged in the alectinib-treated group compared with in the crizotinib-treated group. Subgroup analyses revealed significantly prolonged TTF for alectinib compared with crizotinib therapy in the ALK inhibitor–naive population. OS was significantly longer in the alectinib-treated group than in the crizotinib-treated group. The TTF and OS of patients treated sequentially with crizotinib and then with alectinib after crizotinib failure tended to be longer than those of patients treated with alectinib alone.ConclusionsTherapy with alectinib alone was significantly superior to therapy with crizotinib alone in terms of TTF, PFS, and OS, and sequential therapy with crizotinib and alectinib after crizotinib failure tended to provide a better OS benefit than did therapy with alectinib alone in patients with ALK-positive NSCLC. However, large-scale prospective studies are needed to confirm these observations.     

Diagnostic assays for identification of anaplastic lymphoma kinase‐positive non–small cell lung cancer

In series dominated by adenocarcinoma histology, approximately 5% of non–small cell lung cancers (NSCLCs) harbor an anaplastic lymphoma kinase (ALK) gene rearrangement. Crizotinib, a tyrosine kinase inhibitor with significant activity against ALK, has demonstrated high response rates and prolonged progression‐free survival in ALK‐positive patients enrolled in phase 1/2 clinical trials. In 2011, crizotinib received accelerated approval from the US Food and Drug Administration (FDA) for the treatment of proven ALK‐positive NSCLC using an FDA‐approved diagnostic test. Currently, only break‐apart fluorescence in situ hybridization testing is FDA approved as a companion diagnostic for crizotinib; however, many other assays are available or in development. In the current review, the authors summarize the diagnostic tests available, or likely to become available, that could be used to identify patients with ALK‐positive NSCLC, highlighting the pros and cons of each. Cancer 2013. © 2012 American Cancer Society.