Evaluating larotrectinib for the treatment of advanced solid tumors harboring an NTRK gene fusion

Case report: Tracing in parallel the salivary and gut microbiota profiles to assist Larotrectinib anticancer treatment for NTRK fusion-positive glioblastoma

Oncotherapy can shape intestinal microbiota, which, in turn, may influence therapy effectiveness. Furthermore, microbiome signatures during treatments can be leveraged for the development of personalised therapeutic protocols in cancer treatment based on the identification of microbiota profiles as prognostic tools. Here, for the first time, the trajectory of gut and salivary microbiota in a patient treated with Larotrectinib, a targeted therapy approved for diagnosed glioblastoma multiforme neurotrophic tyrosine receptor kinase (NTRK) gene fusion-positive, has been accurately investigated. We based our analyses on histological diagnosis, genomic and epigenomic profiling of tumour DNA, and faecal and salivary full-length 16S rRNA gene sequencing. The study clearly evidenced a remodelling of the bacterial communities following 1 month of the NTRK-inhibitor treatment, at both gut and oral levels. We reported a boosting of specific bacteria also described in response to other chemotherapeutic approaches, such as Enterococcus faecium, E. hirae, Akkermansia muciniphila, Barnesiella intestinihominis, and Bacteroides fragilis. Moreover, several bacterial species were similarly modulated upon Larotrectinib in faecal and saliva samples. Our results suggest a parallel dynamism of microbiota profiles in both body matrices possibly useful to identify microbial biomarkers as contributors to precision medicine in cancer therapies.

Tissue-Agnostic Targeting of Neurotrophic Tyrosine Receptor Kinase Fusions: Current Approvals and Future Directions

NTRK fusions are oncogenic drivers for multiple tumor types. Therefore, the development of selective tropomyosin receptor kinase (TRK) inhibitors, including larotrectinib and entrectinib, has been transformative in the context of clinical management, given the high rates of responses to these drugs, including intracranial responses in patients with brain metastases. Given their promising activity in pan-cancer cohorts, larotrectinib and entrectinib received U.S. Food and Drug Administration (FDA) and European Medicines Agency (EMA) approval for tissue-agnostic indications in patients with advanced solid tumors harboring NTRK fusions. The safety profiles for both drugs are quite manageable, although neurotoxicity driven by the on-target inhibition of normal NTRK can be a concern. Also, on- and off-target resistance mechanisms can arise during therapy with TRK inhibitors, but they can be addressed with the use of combination therapy and next-generation TRK inhibitors. More recently, the FDA approved the use of repotrectinib, a second-generation TRK inhibitor, in patients with NTRK fusions, based on data suggesting clinical efficacy and safety, which could offer another tool for the treatment of NTRK-altered cancers. In this review, we summarize the current evidence related to the use of TRK inhibitors in the tissue-agnostic setting. We also elaborate on the safety profiles and resistance mechanisms from a practical perspective.

Clinical Relevance of Targeted Therapy and Immune-Checkpoint Inhibition in Lung Cancer

Lung cancer (LC) represents the second most diagnosed tumor and the malignancy with the highest mortality rate. In recent years, tremendous progress has been made in the treatment of this tumor thanks to the discovery, testing, and clinical approval of novel therapeutic approaches. Firstly, targeted therapies aimed at inhibiting specific mutated tyrosine kinases or downstream factors were approved in clinical practice. Secondly, immunotherapy inducing the reactivation of the immune system to efficiently eliminate LC cells has been approved. This review describes in depth both current and ongoing clinical studies, which allowed the approval of targeted therapies and immune-checkpoint inhibitors as standard of care for LC. Moreover, the present advantages and pitfalls of new therapeutic approaches will be discussed. Finally, the acquired importance of human microbiota as a novel source of LC biomarkers, as well as therapeutic targets to improve the efficacy of available therapies, was analyzed. Therapy against LC is increasingly becoming holistic, taking into consideration not only the genetic landscape of the tumor, but also the immune background and other individual variables, such as patient-specific gut microbial composition. On these bases, in the future, the research milestones reached will allow clinicians to treat LC patients with tailored approaches.

Correlation between hypoxia and HGF/c-MET expression in the management of pancreatic cancer

Pancreatic cancer (PC) is very deadly and difficult to treat. The presence of hypoxia has been shown to increase the probability of cancer developing and spreading. Pancreatic ductal adenocarcinoma (PDAC/PC) has traditionally viewed a highly lethal form of cancer due to its high occurrence of early metastases. Desmoplasia/stroma is often thick and collagenous, with pancreatic stellate cells as the primary source (PSCs). Cancer cells and other stromal cells interact with PSCs, promoting disease development. The hepatocyte growth factor (HGF)/c-MET pathway have been proposed as a growth factor mechanism mediating this interaction. Human growth factor (HGF) is secreted by pancreatic stellate cells (PSCs), and its receptor, c-MET, is generated by pancreatic cancer cells and endothelial cells. Hypoxia is frequent in malignant tumors, particularly pancreatic (PC). Hypoxia results from limitless tumor development and promotes survival, progression, and invasion. Hypoxic is becoming a critical driver and therapeutic target of pancreatic cancer as its hypoxia microenvironment is defined. Recent breakthroughs in cancer biology show that hypoxia promotes tumor proliferation, aggressiveness, and therapeutic resistance. Hypoxia-inducible factors (HIFs) stabilize hypoxia signaling. Hypoxia cMet is a key component of pancreatic tumor microenvironments, which also have a fibrotic response, that hypoxia, promotes and modulates. c-Met is a tyrosine-protein kinase. As describe it simply, the MET gene in humans' codes for a protein called hepatocyte growth factor receptor (HGFR). Most cancerous tumors and pancreatic cancer in particular, suffer from a lack of oxygen (PC). Due to unrestrained tumor development, hypoxia develops, actively contributing to tumor survival, progression, and invasion. As the processes by which hypoxia signaling promotes invasion and metastasis become clear, c-MET has emerged as an important determinant of pancreatic cancer malignancy and a potential pharmacological target. This manuscript provides the most current findings on the role of hypoxia and HGF/c-MET expression in the treatment of pancreatic cancer.

Timing of NTRK Gene Fusion Testing and Treatment Modifications Following TRK Fusion Status Among US Oncologists Treating TRK Fusion Cancer

BACKGROUND

Neurotrophic tyrosine receptor kinase (NTRK) gene fusions are oncogenic drivers with an estimated prevalence of less than 1% across all solid tumors. Tropomyosin receptor kinase inhibitors (TRKis) block the constitutively activated tyrosine receptor kinase (TRK) fusion protein produced in NTRK gene fusion positive (NTRK+) tumors from downstream signaling. Tropomyosin receptor kinase inhibitors are now first-line (1L) or subsequent treatment options for TRK fusion cancers.

OBJECTIVE

This study assessed timing of NTRK gene fusion testing and treatment modifications among patients with TRK fusion cancers.

PATIENTS AND METHODS

This was a one-time physician questionnaire with a retrospective, multisite patient chart abstraction of oncology practices in the USA. From June to September 2020, medical oncologists from the Oncology Provider Extended Network (OPEN) who treated patients with NTRK+ advanced/metastatic solid tumors abstracted information into electronic case report forms (eCRFs) for adult patients with advanced/metastatic solid tumors and a NTRK+ tumor test result with a known fusion partner. Use of NTRK testing in routine clinical practice among patients with advanced/metastatic solid tumors was assessed. Data included demographic, clinical, and NTRK gene fusion testing characteristics. Responses were summarized using descriptive statistics.

RESULTS

Twenty-eight community-based medical oncologists who had managed or treated 148 patients with advanced/metastatic TRK fusion cancer between 01/01/2016 and 12/31/2019 completed the survey. Lung (27%), thyroid (18%), salivary gland (14%), and colorectal (12%) were the most commonly reported tumor types. A majority (68%) tested NTRK status prior to 1L initiation; testing after disease progression on 1L (36%), 2L (25%), and 3L (21%) was also noted. Most oncologists (96%) reported no difficulty interpreting NTRK reports. Nearly all (96%) indicated using next-generation sequencing (NGS) for determining NTRK status. The majority (57%) indicated that age, tumor type, and performance status did not impact NTRK testing decisions. Less than half (46%) include TRKi therapy following NTRK+ determination. NTRK testing guidelines were commonly reviewed by physicians (89%).

CONCLUSION AND RELEVANCE

Among patients with advanced/metastatic TRK fusion cancer, medical oncologists reported testing for NTRK fusions at diagnosis or prior to 1L. Future research should elucidate why fewer than half of oncologists surveyed (46%) would not use TRKis after NTRK+ status confirmation, assess clinical practices among NTRK+ patients, and characterize treatment patterns and clinical outcomes in real-world settings.

ESR1 fusions and therapeutic resistance in metastatic breast cancer

Breast cancer is the most frequent female malignant tumor, and the leading cause of cancer death in women worldwide. The most common subtype of breast cancer is hormone receptor positive that expresses the estrogen receptor (ER). Targeting ER with endocrine therapy (ET) is the current standard of care for ER positive (ER+) breast cancer, reducing mortality by up to 40% in early- stage disease. However, resistance to ET represents a major clinical challenge for ER+ breast cancer patients leading to disease recurrence or progression of metastatic disease. Salient drivers of ET resistance are missense mutations in the ER gene (ESR1) leading to constitutive transcriptional activity and reduced ET sensitivity. These mutations are particularly prominent and deleterious in metastatic breast cancer (MBC). In addition to activating ESR1 point mutations, emerging evidence imposes that chromosomal translocation involving the ESR1 gene can also drive ET resistance through the formation of chimeric transcription factors with constitutive transcriptional activity. Although these ESR1 gene fusions are relatively rare, they are enriched in ET resistant metastatic disease. This review discusses the characteristics of ER fusion proteins and their association with clinical outcomes in more aggressive and metastatic breast cancer. The structure and classification of ER fusion proteins based on function and clinical significance are also addressed. Finally, this review summarizes the metastatic phenotypes exhibited by the ER fusion proteins and their role in intrinsic ET resistance.

Pancreatic Cancer and Platelets Crosstalk: A Potential Biomarker and Target

Platelets have been recognized as key players in hemostasis, thrombosis, and cancer. Preclinical and clinical researches evidenced that tumorigenesis and metastasis can be promoted by platelets through a wide variety of crosstalk between cancer cells and platelets. Pancreatic cancer is a devastating disease with high morbidity and mortality worldwide. Although the relationship between pancreatic cancer and platelets in clinical diagnosis is described, the interplay between pancreatic cancer and platelets, the underlying pathological mechanism and pathways remain a matter of intensive study. This review summaries recent researches in connections between platelets and pancreatic cancer. The existing data showed different underlying mechanisms were involved in their complex crosstalk. Typically, pancreatic tumor accelerates platelet aggregation which forms thrombosis. Furthermore, extracellular vesicles released by platelets promote communication in a neoplastic microenvironment and illustrate how these interactions drive disease progression. We also discuss the advantages of novel model organoids in pancreatic cancer research. A more in-depth understanding of tumor and platelets crosstalk which is based on organoids and translational therapies may provide potential diagnostic and therapeutic strategies for pancreatic cancer progression.

SeekFusion - A Clinically Validated Fusion Transcript Detection Pipeline for PCR-Based Next-Generation Sequencing of RNA

Detecting gene fusions involving driver oncogenes is pivotal in clinical diagnosis and treatment of cancer patients. Recent developments in next-generation sequencing (NGS) technologies have enabled improved assays for bioinformatics-based gene fusions detection. In clinical applications, where a small number of fusions are clinically actionable, targeted polymerase chain reaction (PCR)-based NGS chemistries, such as the QIAseq RNAscan assay, aim to improve accuracy compared to standard RNA sequencing. Existing informatics methods for gene fusion detection in NGS-based RNA sequencing assays traditionally use a transcriptome-based spliced alignment approach or a de-novo assembly approach. Transcriptome-based spliced alignment methods face challenges with short read mapping yielding low quality alignments. De-novo assembly-based methods yield longer contigs from short reads that can be more sensitive for genomic rearrangements, but face performance and scalability challenges. Consequently, there exists a need for a method to efficiently and accurately detect fusions in targeted PCR-based NGS chemistries. We describe SeekFusion, a highly accurate and computationally efficient pipeline enabling identification of gene fusions from PCR-based NGS chemistries. Utilizing biological samples processed with the QIAseq RNAscan assay and in-silico simulated data we demonstrate that SeekFusion gene fusion detection accuracy outperforms popular existing methods such as STAR-Fusion, TOPHAT-Fusion and JAFFA-hybrid. We also present results from 4,484 patient samples tested for neurological tumors and sarcoma, encompassing details on some novel fusions identified.