Larotrectinib in patients with TRK fusion-positive solid tumours: a pooled analysis of three phase 1/2 clinical trials

Beyond EGFR, ALK and ROS1: Current evidence and future perspectives on newly targetable oncogenic drivers in lung adenocarcinoma

Lung cancer is the leading cause of cancer death worldwide. In the past decade EGFR, ALK and ROS1 TKIs lead to an unprecedented survival improvement of oncogene-addicted NSCLC patients, with better toxicity profile compared to chemotherapy. In recent years the implementation of high-throughput sequencing platforms led to the identification of uncommon molecular alterations in oncogenic drivers, such as BRAF, MET, RET, HER2 and NTRK. Moreover, newly developed drugs have been found to be active against hard to target drivers, such as KRAS. Specific TKIs targeting these genomic alterations are currently in clinical development and showed impressive activity and survival improvement, leading to FDA-accelerated approval for some of them. However, virtually all patients develop resistance to TKIs by on-target or off-target mechanisms. Here we review the clinicopathological features, the emerging targeted therapies and mechanisms of resistance and strategies to overcome them of KRAS, BRAF, MET, RET, HER2 and NTRK-addicted advanced NSCLCs.

Targeted Therapies in Early Stage NSCLC: Hype or Hope?

Non-small-cell lung cancer (NSCLC) represents roughly 85% of lung cancers, with an incidence that increases yearly across the world. The introduction in clinical practice of several new and more effective molecules has led to a consistent improvement in survival and quality of life in locally advanced and metastatic NSCLC. In particular, oncogenic drivers have indeed transformed the therapeutic algorithm for NSCLC. Nearly 25% of patients are diagnosed in an early stage when NSCLC is still amenable to radical surgery. In spite of this, five-year survival rates for fully resected early stage remains rather disappointing. Adjuvant chemotherapy has shown a modest survival benefit depending on the stage, but more than half of patients relapse. Given this need for improvement, over the last years different targeted therapies have been evaluated in early-stage NSCLC with no survival benefit in unselected patients. However, the identification of reliable predictive biomarkers to these agents in the metastatic setting, the design of molecularly-oriented studies, and the availability of novel potent and less toxic agents opened the way for a novel era in early stage NSCLC treatment. In this review, we will discuss the current landscape of targeted therapeutic options in early NSCLC.

Infantile/Congenital High-Grade Gliomas: Molecular Features and Therapeutic Perspectives

Brain tumors in infants account for less than 10% of all pediatric nervous system tumors. They include tumors diagnosed in fetal age, neonatal age and in the first years of life. Among these, high-grade gliomas (HGGs) are a specific entity with a paradoxical clinical course that sets them apart from their pediatric and adult counterparts. Currently, surgery represents the main therapeutic strategy in the management of these tumors. Chemotherapy does not have a well-defined role whilst radiotherapy is rarely performed, considering its late effects. Information about molecular characterization is still limited, but it could represent a new fundamental tool in the therapeutic perspective of these tumors. Chimeric proteins derived from the fusion of several genes with neurotrophic tyrosine receptor kinase mutations have been described in high-grade gliomas in infants as well as in neonatal age and the recent discovery of targeted drugs may change the long-term prognosis of these tumors, along with other target-driven therapies. The aim of this mini review is to highlight the recent advances in the diagnosis and treatment of high-grade gliomas in infants with a particular focus on the molecular landscape of these neoplasms and future clinical applications.

The Potential Long-Term Comparative Effectiveness of Larotrectinib and Entrectinib for Second-Line Treatment of TRK Fusion-Positive Metastatic Lung Cancer

BACKGROUND

Larotrectinib and entrectinib are FDA-approved therapies for patients with non-small cell lung cancer (NSCLC) with neurotrophic receptor tyrosine kinase gene fusion (TRK fusion-positive) whose cancer has metastasized and progressed. Early evidence indicates that these targeted therapies may offer dramatic survival benefits versus traditional cytotoxic regimens, but it remains uncertain how larotrectinib and entrectinib compare with each other.

OBJECTIVE

To simulate and compare expected life-years and quality-adjusted life-years (QALYs) for both TRK inhibitors.

METHODS

We developed a partitioned survival model to project the long-term comparative effectiveness of larotrectinib versus entrectinib in second-line treatment of metastatic NSCLC. Larotrectinib survival data were derived from a 13-month follow-up of 12 patients with TRK fusion-positive NSCLC in the NCT02122913 (phase 1) and NCT02576431 (NAVIGATE) trials. Entrectinib survival data were derived from a 13-month follow-up of 10 patients with TRK fusion-positive NSCLC in the ALKA-372-001, STARTRK-1, and STARTRK-2 trials. For larotrectinib and entrectinib progression-free survival and overall survival (OS), in-trial survival was extrapolated using parametric curve fits. Exponential fits were selected for all survival models based on minimal Bayesian information criteria and clinical plausibility. Lifetime survival curves were used to estimate expected mean/median survival. QALYs were estimated by applying preprogression and postprogression health state utilities derived from the literature.

RESULTS

In the base case, treatment with larotrectinib and entrectinib resulted in 5.4 and 1.2 median preprogression life-years and 7.0 and 1.8 median total life-years, respectively. Mean preprogression life-years (QALYs) were 7.5 (5.0) and 1.9 (1.2), and mean total life-years (QALYs) were 9.2 (5.8) and 4.4 (2.4), respectively.

CONCLUSIONS

Among TRK inhibitors for metastatic NSCLC, larotrectinib is estimated to provide improved life-year and QALY outcomes versus entrectinib based on parametric extrapolations of in-trial survival data. Our analysis is limited by lack of NSCLC-specific data on entrectinib OS, the small samples of patients with NSCLC in the trials, and a cross-trial comparison. Future studies should re-evaluate the comparative effectiveness of larotrectinib versus entrectinib as more patients are treated and as long-term survival data mature.

DISCLOSURES

Funding for this study was contributed by Bayer Healthcare, which reviewed the manuscript drafts, and employees contributed to the manuscript as coauthors. Xia and Williamson are employees of Bayer Healthcare. Roth, Carlson, and Sullivan are consultants to Bayer Healthcare and retain rights to all final revisions to the manuscript. Carlson also reports fees from Adaptive Biotechnologies, unrelated to this work. Roth reports consulting fees from BMS, unrelated to this work.

Refractory Metastatic Colorectal Cancer: Current Challenges and Future Prospects

Despite advances, patients with metastatic colorectal cancer (mCRC) still have poor long-term survival. Identification of molecular subtypes is important to guide therapy through standard treatment pathways and holds promise for the development of new treatments. Following standard first- and second-line chemotherapy plus targeted agents, many patients retain a reasonable performance status, and thus are seeking further effective treatment to extend life and maintain symptom control. The challenge lies in selecting the most appropriate therapy in the third- and fourth-line settings, from a range of options including the relatively new oral agents TAS-102 and regorafenib, or rechallenge with previous chemotherapy or anti-epidermal growth factor receptor (anti-EGFR) monoclonal antibodies (mAB). Beyond this, therapy consists of trials involving novel agents and new combinations of treatments with theoretical synergy and/or non-overlapping toxicity. There is a great focus on enhancing immunogenicity in mCRC, to reflect the impressive results of immunotherapy drugs in the small cohort with mismatch repair deficient (dMMR) mCRC. Rare molecular subtypes of mCRC are increasingly being identified, including Her2-positive disease, NTRK fusions and others. Clinical trials exploring the efficacy of immunomodulatory and precision agents are plentiful and will hopefully yield clinically meaningful results that can be rapidly translated into routine care.

Current and Future Role of Tyrosine Kinases Inhibition in Thyroid Cancer: From Biology to Therapy

Thyroid cancer represents a heterogenous disease whose incidence has increased in the last decades. Although three main different subtypes have been described, molecular characterization is progressively being included in the diagnostic and therapeutic algorithm of these patients. In fact, thyroid cancer is a landmark in the oncological approach to solid tumors as it harbors key genetic alterations driving tumor progression that have been demonstrated to be potential actionable targets. Within this promising and rapid changing scenario, current efforts are directed to improve tumor characterization for an accurate guidance in the therapeutic management. In this sense, it is strongly recommended to perform tissue genotyping to patients that are going to be considered for systemic therapy in order to select the adequate treatment, according to recent clinical trials data. Overall, the aim of this article is to provide a comprehensive review on the molecular biology of thyroid cancer focusing on the key role of tyrosine kinases. Additionally, from a clinical point of view, we provide a thorough perspective, current and future, in the treatment landscape of this tumor.

Emerging Treatment Options for the Management of Metastatic Colorectal Cancer

An improved understanding of the molecular landscape of metastatic colorectal cancer (CRC) has opened the door for new treatment options. Clinicians should test for molecular alterations that predict resistance to epidermal growth factor receptor (EGFR) inhibitors, such as KRAS and NRAS, and additionally clinically actionable alterations, including BRAF V600 mutations, HER2 amplification, NTRK fusions, and mismatch repair deficiency. Improved outcomes can be achieved with precision treatment strategies for the various CRC subtypes, although clinical features, such as tumor bulk and patient performance status, still help to guide treatment choice. Immune therapies have also produced impressive results in patients with mismatch repair–deficient/microsatellite instability–high tumors. These newer approaches were recently incorporated into the NCCN Guidelines for Colon and Rectal Cancers. In the future, these newer approaches may be used in earlier treatment settings.

TRK fusion positive cancers: From first clinical data of a TRK inhibitor to future directions

Genetic alterations of neurotrophic tropomyosin or tyrosine receptor kinase (NTRK) 1/2/3 genes generate TRK fusion proteins have been reported in a variety of adult and child cancers from diverse cell/tissue lineages. Larotrectinib, a tumour-agnostic TRK inhibitor, has shown remarkable efficacy in a novel "basket" study which has enrolled patients from infants to elderly with different TRK fusion-positive cancers. In this review, we focus on the challenges and expectations on the development of "tumour-agnostic" targeted therapies in rare malignancies.

NTRK testing: First results of the QuiP-EQA scheme and a comprehensive map of NTRK fusion variants and their diagnostic coverage by targeted RNA-based NGS assays

Gene fusions involving the three neurotrophic tyrosine receptor kinase genes NTRK1, NTRK2, or NTRK3 were identified as oncogenic drivers in many cancer types. Two small molecule inhibitors have been tested in clinical trials recently and require the detection of a NTRK fusion gene prior to therapeutic application. Fluorescence in situ hybridization (FISH) and targeted next-generation sequencing (tNGS) assays are commonly used for diagnostic profiling of gene fusions. In the presented study we applied an external quality assessment (EQA) scheme in order to investigate the suitability of FISH and RNA-/DNA-based tNGS for detection of NTRK fusions in a multinational and multicentric ring trial. In total 27 participants registered for this study. Nine institutions took part in the FISH-based and 18 in the NGS-based round robin test, the latter additionally subdivided into low-input and high-input NGS methods (regarding nucleic acid input). Regardless of the testing method applied, all participants received tumor sections of 10 formalin-fixed and paraffin-embedded (FFPE) tissue blocks for in situ hybridization or RNA/DNA extraction, and the results were submitted via an online questionnaire. For FISH testing, eight of nine (88.8%) participants, and for NGS-based testing 15 of 18 (83.3%) participants accomplished the round robin test successfully. The overall high success rate demonstrates that FISH- and tNGS-based NTRK testing can be well established in a routine diagnostic setting. Complementing this dataset, we provide an updated in silico analysis on the coverage of more than 150 NTRK fusion variants by several commercially available RNA-based tNGS panels.

Entrectinib for the treatment of metastatic NSCLC: safety and efficacy

Introduction: Gene fusions are strong driver alterations in various cancers, increasingly diagnosed with multiple testing techniques. ROS1 fusions can be found in 1-2% of non-small cell lung cancer (NSCLC) and several tyrosine kinase inhibitors (TKIs) have been tested in this oncogene-driven disease. NTRK fusions are characteristic of a few rare types of cancer, also infrequently seen in some common cancers including NSCLC. Entrectinib is a newer ROS1 and NTRK inhibitor developed across different tumor types harboring rearrangements in these genes. Entrectinib was granted FDA accelerated approval in August 2019 for the treatment of ROS1+ NSCLC and NTRK-driven solid tumors.Areas covered: This review covers the mechanism of action, safety, and efficacy of entrectinib in patients with metastatic NSCLC.Expert opinion: Entrectinib is an orally bioavailable TKI of TrkA, TrkB, TrkC, and ROS1, with the ability to cross the blood-brain barrier. Entrectinib was effective and well-tolerated in patients harboring ROS1- or NTRK-rearranged NSCLC treated within phase I and II studies. Entrectinib appears to be the most appropriate treatment choice for TKIs-naïve patients, especially in those presenting brain metastasis. Conversely, in case of systemic progression with the evidence of acquired resistance mutations in ROS1 or Trk proteins, a sequential therapy with entrectinib could not be successful.

Systemic Therapy for Hepatocellular Carcinoma: Advances and Hopes

The majority of patients with hepatocellular carcinoma (HCC) are diagnosed at an advanced stage that can only benefit from systemic treatments. Although HCC is highly treatmentresistant, significant achievements have been made in the molecular targeted therapy and immunotherapy of HCC. In addition to regorafenib, cabozantinib and ramucirumab were approved for the second- line targeted treatment by the FDA after disease progression on sorafenib. Nivolumab failed to demonstrate remarkable benefit in overall survival (OS) as first-line therapy, while pembrolizumab did not achieve pre-specified statistical significance in both OS and progression-free survival (PFS) as second-line treatment. Combinations of targeted agents, immune checkpoint inhibitors and other interventions showed favorable results. In this review, we summarized the progress of systemic therapy in HCC and discussed the future directions of the treatment of HCC.