Everolimus in the management of metastatic neuroendocrine tumours

A real-world disproportionality analysis of Everolimus: data mining of the public version of FDA adverse event reporting system

Background: Everolimus is an inhibitor of the mammalian target of rapamycin and is used to treat various tumors. The presented study aimed to evaluate the Everolimus-associated adverse events (AEs) through data mining of the US Food and Drug Administration Adverse Event Reporting System (FAERS). Methods: The AE records were selected by searching the FDA Adverse Event Reporting System database from the first quarter of 2009 to the first quarter of 2022. Potential adverse event signals were mined using the disproportionality analysis, including reporting odds ratio the proportional reporting ratio the Bayesian confidence propagation neural network and the empirical Bayes geometric mean and MedDRA was used to systematically classify the results. Results: A total of 24,575 AE reports of Everolimus were obtained using data from the FAERS database, and Everolimus-induced AEs occurrence targeted 24 system organ classes after conforming to the four algorithms simultaneously. The common significant SOCs were identified, included benign, malignant and unspecified neoplasms, reproductive system and breast disorders, etc. The significant AEs were then mapped to preferred terms such as stomatitis, pneumonitis and impaired insulin secretion, which have emerged in the study usually reported in patients with Everolimus. Of note, unexpected significant AEs, including biliary ischaemia, angiofibroma, and tuberous sclerosis complex were uncovered in the label. Conclusion: This study provided novel insights into the monitoring, surveillance, and management of adverse drug reaction associated with Everolimus. The outcome of serious adverse events and the corresponding detection signals, as well as the unexpected significant adverse events signals are worthy of attention in order to improving clinical medication safety during treatment of Everolimus.

Resistant gastroenteropancreatic neuroendocrine tumors: a definition and guideline to medical and surgical management

Gastroenteropancreatic neuroendocrine tumors (NETs), also historically known as carcinoids, are tumors derived of hormone-secreting enteroendocrine cells. Carcinoids may be found in the esophagus, stomach, small intestine, appendix, colon, rectum, or pancreas. The biologic behavior of carcinoids differs based on their location, with gastric and appendiceal NETs among the least aggressive and small intestinal and pancreatic NETs among the most aggressive. Ultimately, however, biologic behavior is most heavily influenced by tumor grade. The incidence of NETs has increased by 6.4 times over the past 40 years. Surgery remains the mainstay for management of most carcinoids. Medical management, however, is a useful adjunct and/or definitive therapy in patients with symptomatic functional carcinoids, in patients with unresectable or incompletely resected carcinoids, in some cases of recurrent carcinoid, and in postoperative patients to prevent recurrence. Functional tumors with persistent symptoms or progressive metastatic carcinoids despite therapy are called "resistant" tumors. In patients with unresectable disease and/or carcinoid syndrome, an array of medical therapies is available, mainly including somatostatin analogues, molecular-targeted therapy, and peptide receptor radionuclide therapy. Active research is ongoing to identify additional targeted therapies for patients with resistant carcinoids.

Incidence trends and survival analysis of appendiceal tumors in the United States: Primarily changes in appendiceal neuroendocrine tumors

BACKGROUND

Appendiceal tumors are considered to be a relatively rare tumor of the gastrointestinal tract and the prognosis is unclear. This study comprehensively investigated trends in the epidemiology and survival of appendiceal tumors in the United States over the past approximately 20 years.

METHODS

Patients with pathologically confirmed appendiceal tumors from 2000 to 2017 were selected from the Surveillance, Epidemiology and End Results (SEER) database. Age-adjusted incidence rates were calculated by SEER*Stat 8.4.0. The Kaplan-Meier method was used to analyze survival and prognostic factors were investigated by a multivariate Cox proportional risk model.

RESULTS

Ultimately, 13,546 patients with appendiceal tumors between 2000 and 2017 were included. The annual incidence of colonic adenocarcinoma and mucinous adenocarcinoma remained relatively stable. Interestingly, the annual incidence of appendiceal neuroendocrine tumors (aNETs) increased significantly, from 0.03 to 0.90 per 100,000 person-years, with the most dramatic increase in the number of patients with localized disease. Patients with aNETs showed a significant improvement in survival between 2009-2017, compared to the period 2000-2008. Moreover, this improvement in survival over time was seen at all stages (localized, regional, distant) of aNETs. However, this improved survival over time was not seen in colonic and mucinous adenocarcinoma.

CONCLUSIONS

The incidence of appendiceal neoplasms has increased significantly over the past nearly two decades, which is mainly due to the increased incidence and significant migration to earlier stages in aNETs. We must note that despite the increased incidence of aNETs, survival rates have improved at different disease stages.

Management of Appendix Neuroendocrine Neoplasms: Insights on the Current Guidelines

Appendiceal neuroendocrine neoplasms (ANENs) usually present as incidental findings at the time of appendectomy for acute appendicitis. They are rare, accounting for only 0.5-1% of intestinal neoplasms; they are found in 0.3-0.9% of all appendectomy specimens. They are usually sporadic tumors. There are several histological types including well-differentiated neuroendocrine tumors (NETs), poorly differentiated neuroendocrine carcinomas (NECs), and mixed neuroendocrine-non-neuroendocrine neoplasms (MiNENs). Histologic differentiation and the grade of well-differentiated NETs correlate with clinical behavior and prognosis. Management varies based on differentiation, aggressiveness, and metastatic potential. There is debate about the optimal surgical management for localized appendiceal NETs that are impacted by many factors including the tumor size, the extent of mesoappendiceal spread, lymphovascular invasion and perineural involvement. In addition, the data to guide therapy in metastatic disease are limited due to the paucity of these tumors. Here, we review the current advances in the management of ANENs within the context of a multidisciplinary approach to these tumors.

Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia presenting as a solitary lung nodule: a rare histopathological diagnosis

We present a case of diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) in a 56-year-old woman, who presented to our emergency department with a 7-day history of exertional dyspnoea. Due to profound haemodynamic compromise, pulmonary embolism (PE) was suspected, and the patient underwent emergency thrombolysis on admission. A subsequent computerized tomography pulmonary angiogram revealed extensive bilateral PE. Incidentally, a 1.3 cm lesion within the right upper lobe, associated with pleural tethering, was identified. Positron emission tomography computerized tomography and, subsequently, histopathology revealed this lesion to be primary DIPNECH, a rare pre-invasive hyperplasia of neuroendocrine cells. While studies are scarce and cohort numbers are low, somatostatin analogues and protein kinase inhibitors have been proven to reduce symptoms and increase progression-free survival in DIPNECH, respectively.

Sex differences in carcinoid syndrome: A gap to be closed

The incidence of neuroendocrine neoplasms and related carcinoid syndrome (CS) has markedly increased over the last decades and women seem to be more at risk than men for developing CS. Nevertheless, very few studies have investigated sex differences in clinical presentation and outcomes of CS. However, as per other tumours, sex might be relevant in influencing tumour localization, delay in diagnosis, clinical outcomes, prognosis and overall survival in CS. The present review was aimed at evaluating sex differences in CS, as they emerge from an extensive search of the recent literature. It emerged that CS occurs more frequently in female than in male patients with NENs and women seem to have a better prognosis and a slight advantage in overall survival and response to therapy. Moreover, the disease likely impacts differently the quality of life of men and women, with different psychological and social consequences. Nevertheless, sex differences, even if partially known, are deeply underestimated in clinical practice and data from clinical trials are lacking. There is urgent need to increase our understanding of the sex-related differences of CS, in order to define tailored strategies of management of the disease, improving both the quality of life and the prognosis of affected patients.

Lung Neuroendocrine Tumors: How Does Molecular Profiling Help?

PURPOSE OF REVIEW

Lung neuroendocrine tumors (NETs)-typical carcinoids and atypical carcinoids-have unique molecular alterations that are distinct from neuroendocrine carcinomas of the lung and non-small cell lung cancers. Here, we review the role of molecular profiling in the prognosis and treatment of lung NETs.

RECENT FINDINGS

There have been no recently identified molecular prognostic factors for lung NETs and none that have been routinely used to guide management of patients with lung NETs. Previous findings suggest that patients with loss of chromosome 11q may have a worse prognosis along with upregulation of anti-apoptotic pathways (e.g., loss of CD44 and OTP protein expression). Lung NETs rarely harbor driver mutations commonly found in non-small cell lung cancer (NSCLC) or TP53/RB1 mutations found universally in small cell lung cancer. Lung NETs also have low tumor mutation burden and low PD-L1 expression. Everolimus, an mTOR inhibitor and the only FDA approved therapy for unresectable lung NETs, is an effective treatment but the presence of a molecular alteration in the PI3K/AKT/mTOR pathway is not known to predict treatment response. The predominant mutations in lung NETs occur in genes regulating chromatin remodeling and histone modification, with potential targeted therapies emerging in clinical trials. Lung NETs have recurring alterations in genes that regulate the epigenome. Future targeted therapy interfering with epigenetic pathways may hold promise.

Gastroenteropancreatic neuroendocrine neoplasms: A clinical snapshot

Our understanding about the epidemiological aspects, pathogenesis, molecular diagnosis, and targeted therapies of neuroendocrine neoplasms (NENs) have drastically advanced in the past decade. Gastroenteropancreatic (GEP) NENs originate from the enteroendocrine cells of the embryonic gut which share common endocrine and neural differentiation factors. Most NENs are well-differentiated, and slow growing. Specific neuroendocrine biomarkers that are used in the diagnosis of functional NENs include insulin, glucagon, vasoactive intestinal polypeptide, gastrin, somatostatin, adrenocorticotropin, growth hormone releasing hormone, parathyroid hormone-related peptide, serotonin, histamine, and 5-hydroxy indole acetic acid (5-HIAA). Biomarkers such as pancreatic polypeptide, human chorionic gonadotrophin subunits, neurotensin, ghrelin, and calcitonin are used in the diagnosis of non-functional NENs. 5-HIAA levels correlate with tumour burden, prognosis and development of carcinoid heart disease and mesenteric fibrosis, however several diseases, medications and edible products can falsely elevate the 5-HIAA levels. Organ-specific transcription factors are useful in the differential diagnosis of metastasis from an unknown primary of well-differentiated NENs. Emerging novel biomarkers include circulating tumour cells, circulating tumour DNA, circulating micro-RNAs, and neuroendocrine neoplasms test (NETest) (simultaneous measurement of 51 neuroendocrine-specific marker genes in the peripheral blood). NETest has high sensitivity (85%-98%) and specificity (93%-97%) for the detection of gastrointestinal NENs, and is useful for monitoring treatment response, recurrence, and prognosis. In terms of management, surgery, radiofrequency ablation, symptom control with medications, chemotherapy and molecular targeted therapies are all considered as options. Surgery is the mainstay of treatment, but depends on factors including age of the individual, location, stage, grade, functional status, and the heredity of the tumour (sporadic vs inherited). Medical management is helpful to alleviate the symptoms, manage inoperable lesions, suppress postoperative tumour growth, and manage recurrences. Several molecular-targeted therapies are considered second line to somatostatin analogues. This review is a clinical update on the pathophysiological aspects, diagnostic algorithm, and management of GEP NENs.

Gastroenteropancreatic neuroendocrine neoplasms: A clinical snapshot

Our understanding about the epidemiological aspects, pathogenesis, molecular diagnosis, and targeted therapies of neuroendocrine neoplasms (NENs) have drastically advanced in the past decade. Gastroenteropancreatic (GEP) NENs originate from the enteroendocrine cells of the embryonic gut which share common endocrine and neural differentiation factors. Most NENs are well-differentiated, and slow growing. Specific neuroendocrine biomarkers that are used in the diagnosis of functional NENs include insulin, glucagon, vasoactive intestinal polypeptide, gastrin, somatostatin, adrenocorticotropin, growth hormone releasing hormone, parathyroid hormone-related peptide, serotonin, histamine, and 5-hydroxy indole acetic acid (5-HIAA). Biomarkers such as pancreatic polypeptide, human chorionic gonadotrophin subunits, neurotensin, ghrelin, and calcitonin are used in the diagnosis of non-functional NENs. 5-HIAA levels correlate with tumour burden, prognosis and development of carcinoid heart disease and mesenteric fibrosis, however several diseases, medications and edible products can falsely elevate the 5-HIAA levels. Organ-specific transcription factors are useful in the differential diagnosis of metastasis from an unknown primary of well-differentiated NENs. Emerging novel biomarkers include circulating tumour cells, circulating tumour DNA, circulating micro-RNAs, and neuroendocrine neoplasms test (NETest) (simultaneous measurement of 51 neuroendocrine-specific marker genes in the peripheral blood). NETest has high sensitivity (85%-98%) and specificity (93%-97%) for the detection of gastrointestinal NENs, and is useful for monitoring treatment response, recurrence, and prognosis. In terms of management, surgery, radiofrequency ablation, symptom control with medications, chemotherapy and molecular targeted therapies are all considered as options. Surgery is the mainstay of treatment, but depends on factors including age of the individual, location, stage, grade, functional status, and the heredity of the tumour (sporadic vs inherited). Medical management is helpful to alleviate the symptoms, manage inoperable lesions, suppress postoperative tumour growth, and manage recurrences. Several molecular-targeted therapies are considered second line to somatostatin analogues. This review is a clinical update on the pathophysiological aspects, diagnostic algorithm, and management of GEP NENs.

Targeted Therapies in the Management of Well-Differentiated Digestive and Lung Neuroendocrine Neoplasms

OPINION STATEMENT

Ongoing advances in our understanding of neuroendocrine tumor (NET) biology, genetics, and immunology, will continue to expand the availability of targeted therapies, thus improving the outcomes of patients. Well-differentiated neuroendocrine tumors (NETs) are grouped into pancreatic and non-pancreatic NETs (includes GI and thoracic NETs) for treatment considerations (Fig. 1). For panNETs, initial therapy is driven by the need of radiographic response, and targeted agents are typically reserved for second and third line based on the toxicity profile. Treatment options for non-pancreatic NETs are also expanding and while SSAs are the typical first-line option, everolimus and PRRT both remain approved therapies for future lines, and VEGF TKIs are showing promising results in research settings. Sequencing these agents and best time to incorporate peptide receptor radio therapy into the management algorithm remains an unmet need.

An Update on Gastroenteropancreatic Neuroendocrine Neoplasms: From Mysteries to Paradigm Shifts

Although neuroendocrine neoplasms (NEN) were once thought to be rare and mostly "benign" diseases, they are now being redefined in light of recently discovered molecular information. NENs constitute a spectrum of variably differentiated neoplasms, ranging from well-differentiated tumors with a protracted course over many years to very aggressive neuroendocrine carcinomas. Although the majority of NEN are non-functional lesions, some of these tumors, do produce a hormonal hypersecretion syndrome. Their reappraisal has led scientist to unveil previously unknown oncogenic pathways and connections that resulted in a new category in the International Classification of Diseases (ICD-11) and a revised version of the World Health Organization Classification (WHO 2018). Complex diseases like NEN require a multidisciplinary approach that includes the perspectives of endocrinologists, medical and surgical oncologists, radiation oncologists, imaging specialists and pathologists. There are currently virtually thousands of ongoing trials evaluating the efficacy and safety of several molecular targeted therapies. The purpose of this review was to critically evaluate recent information regarding the pathogenesis, diagnosis and treatment of NEN.

Molecular Mechanisms Underlying Autophagy-Mediated Treatment Resistance in Cancer

Despite advances in diagnostic tools and therapeutic options, treatment resistance remains a challenge for many cancer patients. Recent studies have found evidence that autophagy, a cellular pathway that delivers cytoplasmic components to lysosomes for degradation and recycling, contributes to treatment resistance in different cancer types. A role for autophagy in resistance to chemotherapies and targeted therapies has been described based largely on associations with various signaling pathways, including MAPK and PI3K/AKT signaling. However, our current understanding of the molecular mechanisms underlying the role of autophagy in facilitating treatment resistance remains limited. Here we provide a comprehensive summary of the evidence linking autophagy to major signaling pathways in the context of treatment resistance and tumor progression, and then highlight recently emerged molecular mechanisms underlying autophagy and the p62/KEAP1/NRF2 and FOXO3A/PUMA axes in chemoresistance.

EPB41L5 is Associated With the Metastatic Potential of Low-grade Pancreatic Neuroendocrine Tumors

BACKGROUND/AIM

Low-grade pancreatic neuroendocrine tumors (LG-PNETs) behave unpredictably. The aim of the study was to identify biomarkers that predict PNET metastasis to improve treatment selection.

PATIENTS AND METHODS

Five patients with primary non-metastatic LG-PNETs, six with primary LG-PNETs with synchronous or metachronous metastases (M-PNETs), and six metastatic to liver LG-PNETs (ML-PNETs) from the group of six M-PNET patients were selected. RNA data were normalized using iterative rank-order normalization. Student's t-test identified differentially-expressed genes in LG-PNETs versus M-PNETs. A 2-fold difference in expression was considered to be significant. Results were validated with an independent dataset of LG-PNETs and metastatic LG-PNETs.

RESULTS

Overall, 195 genes had a >2-fold change (in either direction). A total of 29 genes were differentially overexpressed in M-PNETs. Erythrocyte membrane protein band 4.1-like 5 (EPB41L5) had a 2.07-fold change increase in M-PNETs and the smallest p-value. EPB41L5 was not statistically different between M-PNETs and ML-PNETs. EPB41L5 differential expression between primary and metastatic LG-PNETs was confirmed by immunohistochemistry.

CONCLUSION

These results support further investigation into whether EPB41L5 is a biomarker of PNETs with high risk for metastases.

Biological and Biochemical Basis of the Differential Efficacy of First and Second Generation Somatostatin Receptor Ligands in Neuroendocrine Neoplasms

Endogenous somatostatin shows anti-secretory effects in both physiological and pathological settings, as well as inhibitory activity on cell growth. Since somatostatin is not suitable for clinical practice, researchers developed synthetic somatostatin receptor ligands (SRLs) to overcome this limitation. Currently, SRLs represent pivotal tools in the treatment algorithm of neuroendocrine tumors (NETs). Octreotide and lanreotide are the first-generation SRLs developed and show a preferential binding affinity to somatostatin receptor (SST) subtype 2, while pasireotide, which is a second-generation SRL, has high affinity for multiple SSTs (SST₅ > SST₂ > SST₃ > SST₁). A number of studies demonstrated that first-generation and second-generation SRLs show distinct functional properties, besides the mere receptor affinity. Therefore, the aim of the present review is to critically review the current evidence on the biological effects of SRLs in pituitary adenomas and neuroendocrine tumors, by mainly focusing on the differences between first-generation and second-generation ligands.

2-Oxonanonoidal Antibiotic Actinolactomycin Inhibits Cancer Progression by Suppressing HIF-1α

HIF-1 serves as an important regulator in cell response to hypoxia. Due to its key role in promoting tumor survival and progression under hypoxia, HIF-1 has become a promising target of cancer therapy. Thus far, several HIF-1 inhibitors have been identified, most of which are from synthesized chemical compounds. Here, we report that ALM (ActinoLactoMycin), a compound extracted from metabolites of Streptomyces flavoretus, exhibits inhibitory effect on HIF-1α. Mechanistically, we found that ALM inhibited the translation of HIF-1α protein by suppressing mTOR signaling activity. Treatment with ALM induced cell apoptosis and growth inhibition of cancer cells both in vitro and in vivo in a HIF-1 dependent manner. More interestingly, low dose of ALM treatment enhanced the anti-tumor effect of Everolimus, an inhibitor of mTOR, suggesting its potential use in combination therapy of tumors, especially solid tumor patients. Thus, we identified a novel HIF-1α inhibitor from the metabolites of Streptomyces flavoretus, which shows promising anti-cancer potential.

Assessment of change in quality of life, carcinoid syndrome symptoms and healthcare resource utilization in patients with carcinoid syndrome

BACKGROUND

There is limited information on changes over time in carcinoid syndrome (CS) symptoms and quality of life (QoL). This study assessed change in CS symptoms and QoL in patients treated with somatostatin analogs (SSAs) using the Functional Assessment of Cancer Therapy-General (FACT-G) and Patient-Reported Outcomes Measurement Information System (PROMIS)-29 instruments.

METHODS

Patients ≥18 years old with CS symptoms and treated with SSA or non-SSA agents in the United States were recruited through a patient advocacy group to complete a two-part, anonymous online survey. Time point (T) 1 survey was fielded from July-October 2016, and T2 survey followed 6 months later. Clinical characteristics and SSA treatment duration were assessed at T1. FACT-G and PROMIS-29 QoL surveys were administered and CS symptoms were assessed at T1 and T2; proportions of patients not experiencing symptoms were compared by McNemar's test. Healthcare resource utilization (HRU) was assessed for the T1-T2 interval, and mean difference in QoL score from T1 to T2 by SSA duration was calculated.

RESULTS

Of 117 participants at T1, 89 (76%) completed the T2 survey and served as the study sample; 11 (13%) were treated with SSAs for > 0-2 years, 37 (42%) for > 2-5 years, and 39 (45%) for > 5 years. A higher proportion of patients at T2 vs. T1 reported the following symptoms as not applicable: diarrhea (16% vs. 7%, p < 0.05), flushing (28% vs. 18%, p < 0.05), wheezing (78% vs 66%, p = 0.008). Most patients (89%) had a physical exam and a mean of 7.2 healthcare provider visits between T1 and T2. Patients treated with SSAs for ≤2 years had a mean positive change of 3.7 in their FACT-G total score between surveys, and 6.0 in an additional set of CS-specific questions. Patients receiving SSAs for > 2 years did not appear to associate with a clinically meaningful improvement in QoL score as assessed by FACT-G between T1 and T2; patients also had no clinically meaningful improvement as assessed by PROMIS-29.

CONCLUSIONS

There may be clinically important improvement in QoL as measured by FACT-G in patients in earlier years of receiving SSA, which may not appear in later years of SSA treatment.

The Oncolytic Herpes Simplex Virus Talimogene Laherparepvec Shows Promising Efficacy in Neuroendocrine Cancer Cell Lines

Metastatic neuroendocrine cancer still constitutes a palliative situation, lacking promising treatment options. Oncolytic virotherapy, a novel type of virus-based immunotherapy, lyses tumor cells using genetically engineered viruses thereby activating the immune system to induce an optimized antitumor response which could bring down tumor masses to a stage of minimal residual tumor disease. The oncolytic vector talimogene laherparepvec (T-VEC, herpes simplex virus [HSV] type 1) has already shown excellent safety profiles in clinical studies and has become the first ever FDA/EMA-approved oncolytic virus (OV). This work presents a first preclinical assessment of this state-of-the-art OV, using a panel of human neuroendocrine tumor/neuroendocrine carcinoma (NET/NEC) cell lines. Cytotoxicity, transgene expression, and viral replication patterns were studied. Furthermore, the antiproliferative activity was compared to the one of mTOR inhibitor Everolimus and also interactions between the OV and Everolimus were evaluated. Moreover, virostatic effects of ganciclovir (GCV) on replication of T-VEC were assessed and electron microscopic pictures were taken to comprehend viral envelopment and details of the replication cycle of T-VEC in human neuroendocrine cancer. It could be shown that T-VEC infects, replicates in, and lyses human NET/NEC cells exhibiting high oncolytic efficiencies already at quite low virus concentrations. Interestingly, Everolimus was not found to have any relevant impact on rates of viral replication, but no additive effects could be proved using a combinatorial therapy regimen. On the other hand, GCV was shown to be able to limit replication of T-VEC, thus establishing an important safety feature for future treatments of NET/NEC patients. Taken together, T-VEC opens up a promising novel treatment option for NET/NEC patients, warranting its further preclinical and clinical development.

Phase II Study of Everolimus and Octreotide LAR in Patients with Nonfunctioning Gastrointestinal Neuroendocrine Tumors: The GETNE1003_EVERLAR Study

BACKGROUND

Antitumor activity of the combination of somatostatin analogues (SSAs) and the mammalian target of rapamycin (mTOR) inhibitor everolimus in patients with neuroendocrine tumors (NETs) has been reported but not confirmed in prospective trials.

MATERIALS AND METHODS

This prospective, multicenter, single-arm phase II EVERLAR study evaluated everolimus 10 mg/day and the SSA octreotide 30 mg every 28 days in patients with advanced nonfunctioning well-differentiated gastrointestinal NETs (GI-NETs) that progressed in the last 12 months (ClinicalTrials.gov NCT01567488). Prior treatment with SSAs and any systemic or locoregional therapy was allowed except for mTOR inhibitors. Patients continued treatment until disease progression or unacceptable adverse events (AEs). The primary endpoint was progression-free survival (PFS) at 12 months; secondary endpoints included early biochemical response, objective response rate (ORR) by RECIST v1.0, overall survival (OS), AEs, activation of mTOR pathway (insulin-like growth factor 1 receptor [IGF1R] and phosphoS6 [pS6] expression).

RESULTS

Forty-three patients were included in the intent-to-treat analyses. After 12 months of treatment, 62.3% (95% confidence interval [CI] 48%-77%) of patients had not progressed or died. The 24-month PFS rate was 43.6% (95% CI 29%-58%). The confirmed ORR was 2.3%, and stable disease was 58.1%. Median OS was not reached after 24 months of median follow-up. Dose reductions and temporary interruptions due to AEs were required in 14 (33%) and 33 (77%) patients, respectively. The most frequent AEs were diarrhea, asthenia, mucositis, rash, and hyperglycemia. No correlation was observed between IGFR1 and pS6 expression and PFS/OS.

CONCLUSION

The everolimus-octreotide combination provided clinically relevant efficacy in nonfunctioning GI-NETs, similar to the results of RADIANT-2 in functioning setting.

IMPLICATIONS FOR PRACTICE

The EVERLAR study reports prospective data of somatostatin analogue in combination with everolimus in nonfunctioning gastrointestinal neuroendocrine tumors suggesting meaningful activity and favorable toxicity profile that supports drug combination in this setting.

The role of GSK3 and its reversal with GSK3 antagonism in everolimus resistance

Pancreatic neuroendocrine tumors (panNETs) are often inoperable at diagnosis. The mTORC1 inhibitor everolimus has been approved for the treatment of advanced NETs. However, the regular development of resistance to everolimus limits its clinical efficacy. We established two independent everolimus-resistant panNET (BON1) cell lines (BON1 RR1, BON1 RR2) to find potential mechanisms of resistance. After 24 weeks of permanent exposure to 10 nM everolimus, BON1 RR1 and BON1 RR2 showed stable resistance with cellular survival rates of 96.70% (IC₅₀ = 5200 nM) and 92.30% (IC₅₀ = 2500 nM), respectively. The control cell line showed sensitivity to 10 nM everolimus with cellular survival declining to 54.70% (IC₅₀ = 34 nM). Both resistant cell lines did not regain sensitivity over time and showed persistent stable resistance after a drug holiday of 13 weeks. The mechanisms of resistance in our cell line model included morphological adaptations, G1 cell cycle arrest associated with reduced CDK1(cdc2) expression and decreased autophagy. Cellular migration potential was increased and indirectly linked to c-Met activation. GSK3 was over-activated in association with reduced baseline IRS-1 protein levels. Specific GSK3 inhibition strongly decreased BON1 RR1/RR2 cell survival. The combination of everolimus with the PI3Kα inhibitor BYL719 re-established everolimus sensitivity through GSK3 inhibition and restoration of autophagy. We suggest that GSK3 over-activation combined with decreased baseline IRS-1 protein levels and decreased autophagy may be a crucial feature of everolimus resistance, and hence, a possible therapeutic target.

Quality of Life in Patients with Metastatic Gastroenteropancreatic Neuroendocrine Tumors Receiving Peptide Receptor Radionuclide Therapy: Information from a Monitoring Program in Clinical Routine

In patients with metastatic gastroenteropancreatic neuroendocrine tumors (NETs), we evaluated health-related quality of life (HRQoL) from the first peptide receptor radionuclide therapy (PRRT) to the first restaging and compared the scores with general-population (GP) norms. Methods: The data were from routine HRQoL monitoring using the core quality-of-life questionnaire of the European Organization for Research and Treatment of Cancer (EORTC QLQ-C30). Patients received 4-6 cycles of ¹⁷⁷Lu-DOTATATE or ⁹⁰Y-DOTATOC. To be eligible for analysis, patients had to have at least one HRQoL assessment before PRRT and at least one HRQoL assessment at the end of or after treatment completion. Linear mixed models were used to consider HRQoL changes over time. Results: In total, 61 gastroenteropancreatic NET patients (small-intestine NETs, n = 37; pancreatic NETs, n = 24) were eligible for analysis. Clear improvements from baseline to the first restaging were found for diarrhea in small-intestine NET patients, showing a decrease of 16 points, which represents a moderately large change. We observed a clinically relevant decrease in appetite loss (17 points), but for female small-intestine NET patients only. Other HRQoL changes were also restricted to sociodemographic or clinical subgroups and mainly reflected improvements, except for physical and social functioning, which showed decreasing scores in older small-intestine NET patients. Compared with HRQoL GP norms, patients had impairments consisting of diarrhea; fatigue; appetite loss; reduced physical, social, and role functioning; and reduced global HRQoL. Except for diarrhea and appetite loss, patient scores at the first restaging did not reach GP levels. Conclusion: Our analyses support previous findings of overall stable HRQoL under PRRT. Yet, significant HRQoL impairments compared with the GP and potentially specific subgroup patterns need to be considered.

Open issues on G3 neuroendocrine neoplasms: back to the future

The recent recognition that grade 3 (G3) neuroendocrine neoplasms (NENs) can be divided into two different categories according to the histopathological differentiation, that is G3 neuroendocrine tumors (NETs) and G3 neuroendocrine carcinomas (NECs) has generated a lot of interest concerning not only the diagnosis, but also the differential management of such new group of NENs. However, several issues need to be fully clarified in order to put G3 NETs and G3 NECs in the right place. The aim of this review is to focus on those issues that are still undetermined starting from the current knowledge, evaluating the available evidence and the possible clinical implications.

Diabetes and pancreatic neuroendocrine tumours: Which interplays, if any?

Pancreatic neuroendocrine tumours (PanNETs) represent an uncommon type of pancreatic neoplasm, whose incidence is increasing worldwide. As per exocrine pancreatic cancer, a relationship seems to exist between PanNETs and glycaemic alterations. Diabetes mellitus (DM) or impaired glucose tolerance often occurs in PanNET patients as a consequence of hormonal hypersecretion by the tumour, specifically affecting glucose metabolism, or due to tumour mass effects. On the other hand, pre-existing DM may represent a risk factor for developing PanNETs and is likely to worsen the prognosis of such patients. Moreover, the surgical and/or pharmacological treatment of the tumour itself may impair glucose tolerance, as well as antidiabetic therapies may impact tumour behaviour and patients outcome. Differently from exocrine pancreatic tumours, few data are available for PanNETs as yet on this issue. In the present review, the bidirectional association between glycaemic disorders and PanNETs has been extensively examined, since the co-existence of both diseases in the same individual represents a further challenge for the clinical management of PanNETs.

Primary hepatic neuroendocrine carcinoma: report of two cases and literature review

Background

Primary hepatic neuroendocrine carcinoma (PHNEC) is extremely rare. The diagnosis of PHNEC remains challenging—partly due to its rarity, and partly due to its lack of unique clinical features. Available treatment options for PHNEC include surgical resection of the liver tumor(s), radiotherapy, liver transplant, transcatheter arterial chemoembolization (TACE), and administration of somatostatin analogues.

Case presentation

We report two male PHNEC cases and discuss the diagnosis and treatment options. Both cases presented with abdominal pain; case two also presented with symptoms of jaundice. The initial diagnosis for both cases was poorly differentiated grade 3 small-cell neuroendocrine carcinoma, based on imaging characteristics and the pathology of liver biopsies. Final diagnoses of PHNEC were arrived at by ruling out non-hepatic origins. Case one presented with a large tumor in the right liver lobe, and the patient was treated with TACE. Case two presented with tumors in both liver lobes, invasions into the left branch of hepatic portal vein, and metastasis in the hepatic hilar lymph node. This patient was ineligible for TACE and was allergic to the somatostatin analogue octreotide. This limited treatment options to supportive therapies such as albumin supplementation for liver protection. Patient one and two died at 61 and 109 days, respectively, following initial hospital admission.

Conclusions

We diagnosed both cases with poorly differentiated grade 3 small-cell PHNEC through imaging characteristics, immunohistochemical staining of liver biopsies, and examinations to eliminate non-hepatic origins. Neither TACE nor liver protection appeared to significantly extend survival time of the two patients, suggesting these treatments may be inadequate to improve survival of patients with poorly differentiated grade 3 small-cell PHNEC. The prognosis of poorly differentiated grade 3 small-cell PHNEC is poor due to limited and ineffective treatment options.

Electronic supplementary material

The online version of this article (10.1186/s12907-018-0070-7) contains supplementary material, which is available to authorized users.

Emerging use of everolimus in the treatment of neuroendocrine tumors

Neuroendocrine tumors (NETs) consist of a diverse family of malignancies, which are derived from neuroendocrine cells, most commonly originating from the gastroenteropancreatic (GEP) tract or the bronchopulmonary system. In general, NETs are more indolent than epithelial tumors, with median survival rates of longer than 30 months. The upregulation of mTOR pathway has been shown to play a pivotal role in NET pathogenesis. Inhibition of mTOR protein with everolimus represents a progress in the treatment of advanced NETs. Everolimus has shown a significant improvement in progression-free survival (PFS) among patients with pancreatic NETs (pNETs) and nonfunctional GEP and lung NETs in the Phase III RAD001 in Advanced Neuroendocrine Tumors (RADIANT)-3 and RADIANT-4 studies, respectively. In addition, the combination of everolimus with octreotide showed a clinically significant improvement versus octreotide alone in functional NETs in the RADIANT-2 trial. These studies led to the US Food and Drug Administration (FDA) and European Medical Agency (EMA) approval of everolimus. Safety profile of everolimus is generally acceptable. The most common adverse events are stomatitis, diarrhea, rash and fatigue. There is a growing range of novel treatment options in the setting of NETs, but there are no data comparing the activity of different treatment strategies. Thus, treatment decisions are based on different aspects, such as clinical course, patient symptomatology, primary tumor site, tumor functionality, rate of progression and burden of disease. Further research is required to clarify the treatment sequencing to achieve the maximum prolongation in survival and maintenance of quality of life. Future research should concentrate on identification of predictive biomarkers for benefit from different therapies, and studies should also include quality of life as an important measurement in this disease.

The MTH1 inhibitor TH588 demonstrates anti-tumoral effects alone and in combination with everolimus, 5-FU and gamma-irradiation in neuroendocrine tumor cells

Modulation of the redox system in cancer cells has been considered a promising target for anti-cancer therapy. The novel MTH1 inhibitor TH588 proved tremendous potential in terms of cancer cell eradication, yet its specificity has been questioned by recent reports, indicating that TH588 may also induce cancer cell death by alternative mechanisms than MTH1 inhibition. Here we used a panel of heterogeneous neuroendocrine tumor cells in order to assess cellular mechanisms and molecular signaling pathways implicated in the effects of TH588 alone as well as dual-targeting approaches combining TH588 with everolimus, cytotoxic 5-fluorouracil or γ-irradiation. Our results reflect that TH588 alone efficiently decreased the survival of neuroendocrine cancer cells by PI3K-Akt-mTOR axis downregulation, increased apoptosis and oxidative stress. However, in the dual-targeting approaches cell survival was further decreased due to an even stronger downregulation of the PI3K-Akt-mTOR axis and augmentation of apoptosis but not oxidative stress. Furthermore, we could attribute TH588 chemo- and radio-sensitizing properties. Collectively our data not only provide insights into how TH588 exactly kills cancer cells but also depict novel perspectives for combinatorial treatment approaches encompassing TH588.