Targeted therapies in neuroendocrine tumors (NET): clinical trial challenges and lessons learned

Somatostatin Receptor Subtype-2 Targeting System for Specific Delivery of Temozolomide

Temozolomide (TMZ) is a DNA alkylating agent that produces objective responses in patients with neuroendocrine tumors (NETs) when the DNA repair enzyme O6-methylguanine-DNA methyltransferase (MGMT) is inactivated. At high doses, TMZ therapy exhausts MGMT activity but also produces dose-limiting toxicities. To reduce off-target effects, we converted the clinically approved radiotracer 68Ga-DOTA-TOC into a peptide-drug conjugate (PDC) for targeted delivery of TMZ to somatostatin receptor subtype-2 (SSTR2)-positive tumor cells. We used an integrated radiolabeling strategy for direct quantitative assessment of receptor binding, pharmacokinetics, and tissue biodistribution. In vitro studies revealed selective binding to SSTR2-positive cells with high affinity (5.98 ± 0.96 nmol/L), internalization, receptor-dependent DNA damage, cytotoxicity, and MGMT depletion. Imaging and biodistribution analysis showed preferential accumulation of the PDC in receptor-positive tumors and high renal clearance. This study identified a trackable SSTR2-targeting system for TMZ delivery and utilizes a modular design that could be broadly applied in PDC development.

Characteristics and treatment results of patients with gastroenteropancreatic neuroendocrine tumors in a tertiary care centre

BACKGROUND

Gastroenteropancreatic Neuroendocrine tumors (GEP-NET) are rare neoplasms with limited reported data from the Middle East. Our study aims to report the clinicopathological feature, treatment patterns, and survival outcomes of patients with GEP-NET from our part of the world.

METHODS

Medical records of patients diagnosed with GEP-NET between January 2011 and December 2016 at a single center in Saudi Arabia were reviewed retrospectively, and complete clinicopathological and treatment data were collected. Patients' survival was estimated by the Kaplan-Meier method.

RESULTS

A total of 72 patients were identified with a median age of 51 years (range 27-82) and male-to-female ratio of (1.1). The most common tumor location was the pancreas (29.1%), followed by small bowel (25%), stomach (12.5%), rectum (8.3%), colon (8.3%), and appendix (6.9%). Forty-one patients (57%) had well-differentiated grade (G)1, 21 (29%) had G2, and 4 (6%) had G3. In five patients, the pathology was neuroendocrine carcinoma and in one it could not be classified. 54.2% of the patients were metastatic at diagnosis. Forty-two patients underwent surgical resection as primary management while 26 underwent systemic therapy, three patients were put on active surveillance, and one was treated endoscopically with polypectomy. The 5-year overall survival and progression-free survivals were 77.2% and 49%, respectively, for the whole group. Patients with G1 and 2 disease, lower Ki-67 index, and surgically treated as primary management had significantly better survival outcomes.

CONCLUSION

Our study suggests that the most common tumor locations are similar to western reported data. However, there seems to be a higher incidence of metastatic disease at presentation than in the rest of the world.

High-Contrast Detection of Somatostatin Receptor Subtype-2 for Fluorescence-Guided Surgery

Dye design can influence the ability of fluorescently labeled imaging agents to generate tumor contrast and has become an area of significant interest in the field of fluorescence-guided surgery (FGS). Here, we show that the charge-balanced near-infrared fluorescent (NIRF) dye FNIR-Tag enhances the imaging properties of a fluorescently labeled somatostatin analogue. In vitro studies showed that the optimized fluorescent conjugate MMC(FNIR-Tag)-TOC bound primarily via somatostatin receptor subtype-2 (SSTR2), whereas its negatively charged counterpart with IRDye 800CW had higher off-target binding. NIRF imaging in cell line- and patient-derived xenograft models revealed markedly higher tumor contrast with MMC(FNIR-Tag)-TOC, which was attributed to increased tumor specificity. Ex vivo staining of surgical biospecimens from primary and metastatic tumors, as well as involved lymph nodes, demonstrated binding to human tumors. Finally, in an orthotopic tumor model, a simulated clinical workflow highlighted our unique ability to use standard preoperative nuclear imaging for selecting patients likely to benefit from SSTR2-targeted FGS. Our findings demonstrate the translational potential of MMC(FNIR-Tag)-TOC for intraoperative imaging and suggest broad utility for using FNIR-Tag in fluorescent probe development.

The quality of clinical trials in neuroendocrine tumours; have we learnt from our mistakes? An evaluation of phase II and phase III clinical trials

The quality and reporting of neuroendocrine tumour (NET) clinical trials has previously been found to be heterogeneous impairing trial interpretability. We aimed to perform an updated review of the quality of phase II/III clinical trials in NET to assess if trial design and reporting have improved since 2011. We performed a PubMed search for phase II/III trials evaluating systemic anticancer therapies or liver-directed therapies published between 2011 and 2018. Data collected comprised administrative data, study population characteristics, endpoints, reporting and statistical design parameters, and results. Sixty studies were included (5218 patients): 50 phase II and 10 phase III trials. Study populations were heterogeneous: 52% of trials allowed tumours from various primary sites, 28% allowed both well- and poorly-differentiated tumour morphology or did not specify, and 57% did not report proliferative indices and/or tumour grade in ≥80% of the study population. Only 36% of trials mandated radiological disease progression on participant enrolment using a validated measure. Statistical design and primary endpoint were clearly defined in 67% and 88% of trials, respectively. Toxicity (88%), radiological response rate (85%) and progression-free survival/time to progression (82%) were well reported in a majority of trials, but health-related quality of life was included in the minority. Of the randomised trials (n = 11), study populations were more homogeneous and study design was more often clearly defined; however, only 45% mandated radiological progression at baseline as measured per Response Evaluation Criteria In Solid Tumours, and reporting of health-related quality of life (55%) remained suboptimal. The design and reporting of NET clinical trials, predominantly of single-arm phase II trials, remains suboptimal and has not considerably improved over time despite the growth in our knowledge of the biology and unique characteristics of NETs. Higher quality is seen in randomised trials, although certain design and reporting elements remain inadequate in some studies. We must prioritise the design and conduct of NET clinical trials to effectively inform future research and guide practice change.

Clinical and Translational Research Challenges in Neuroendocrine Tumours

Neuroendocrine tumours (NETs) represent a range of neoplasms that may arise from any (neuro)endocrine cell situated in any part of the human body. As any other rare diseases, NETs face several difficulties in relation to research. This review will describe some of the main challenges and proposed solutions faced by researchers with expertise in rare malignancies. Some of the most common challenges in clinical and translational research are enumerated in this review, covering aspects from clinical, translational and basic research. NETs being a heterogeneous group of diseases and a limited sample size of clinical and translational research projects are the main challenges. Challenges with NETs lay over the disparities between healthcare models to tackle rare diseases. NETs add an extra layer of complexity due to a numerous group of different entities. Prospective real-world data trials are an opportunity for rare cancers with the revolution of electronic health technologies. This review explores potential solutions to these challenges that could be useful not only to the NET community but also to other rare tumours researchers.

Pre-operative dysglycemia is associated with decreased survival in patients with pancreatic neuroendocrine neoplasms

BACKGROUND

Diabetes mellitus is associated with increased risk of pancreatic cancer and impaired postresection survival. For pancreatic neuroendocrine neoplasms, no evidence is available for a similar effect of diabetes mellitus. The aim of this study was to evaluate the glycemic profile in patients with pancreatic neuroendocrine neoplasms and to assess the potential impact of glycemic control on the pathology and long-term outcomes in patients undergoing resection of pancreatic neuroendocrine neoplasms.

METHODS

Pancreatic resections from 2001 to 2017 for pancreatic neuroendocrine neoplasms were analyzed from prospective databases. Blood glucose and HbA1c levels were collected from preoperative tests. Preoperative dysglycemia was defined as a blood glucose ≥140 mg% and/or HbA1c ≥6.5%. Uni- and multivariate analyses were performed according to the presence of perioperative dysglycemia. Survival analyses were performed by Kaplan-Meier curves and Cox-proportional hazards method.

RESULTS

Four hundred and seventeen patients were analyzed. Medical history was positive for diabetes mellitus in 88 (21.1%) patients. Blood glucose evaluation identified 30 additional patients without a prior diagnosis of diabetes mellitus who had preoperative dysglycemia. No differences regarding pathologic characteristics or outcomes were detected between diabetics and non-diabetics. Conversely, patients with dysglycemia had greater rates of metastasis (16.8% vs 27.4%; P = .027) as well as vascular, perineural, and lympho-vascular involvement than those with normal blood glucose (89.2% vs 57.4%; P < .001, 90.0% vs 65.1%; P = .046, and 89.3% vs 61.3; P = .006, respectively). Preoperative dysglycemia was associated with impaired overall survival (hazard ratio = 1.57 [1.01-2.46]) and recurrence-free survival (hazard ratio = 1.78 [1.01-3.12]). By multivariate analysis, preoperative dysglycemia was independently associated with recurrence-free survival (hazard ratio 2.32 [1.29-4.17]), together with lymph-node involvement (hazard ratio = 2.01 [1.14-3.57]) and metastatic disease (hazard ratio = 5.10 [2.73-9.55]).

CONCLUSION

Preoperative dysglycemia, but not diabetes mellitus per se, is associated with advanced disease and impaired long-term outcomes in patients undergoing resection for a pancreatic neuroendocrine neoplasm. For those patients, closer surveillance and strict glycemic control are warranted.

A side-by-side evaluation of [18F]FDOPA enantiomers for non-invasive detection of neuroendocrine tumors by positron emission tomography

Neuroendocrine tumors (NETs) are an extremely heterogenous group of malignancies with variable clinical behavior. Molecular imaging of patients with NETs allows for effective patient stratification and treatment guidance and is crucial in selection of targeted therapies. Positron emission tomography (PET) with the radiotracer L-[¹⁸F]FDOPA is progressively being utilized for non-invasive in vivo visualization of NETs and pancreatic β-cell hyperplasia. While L-[¹⁸F]FDOPA-PET is a valuable tool for disease detection and management, it also exhibits significant diagnostic limitations owing to its inherent physiological uptake in off-target tissues. We hypothesized that the D-amino acid structural isomer of that clinical tracer, D-[¹⁸F]FDOPA, may exhibit superior clearance capabilities owing to a reduced in vivo enzymatic recognition and enzyme-mediated metabolism. Here, we report a side-by-side evaluation of D-[¹⁸F]FDOPA with its counterpart clinical tracer, L-[¹⁸F]FDOPA, for the non-invasive in vivo detection of NETs. In vitro evaluation in five NET cell lines, including invasive small intestinal neuroendocrine carcinomas (STC-1), insulinomas (TGP52 and TGP61), colorectal adenocarcinomas (COLO-320) and pheochromocytomas (PC12), generally indicated higher overall uptake levels of L-[¹⁸F]FDOPA, compared to D-[¹⁸F]FDOPA. While in vivo PET imaging and ex vivo biodistribution studies in PC12, STC-1 and COLO-320 mouse xenografts further supported our in vitro data, they also illustrated lower off-target retention and enhanced clearance of D-[¹⁸F]FDOPA from healthy tissues. Cumulatively our results indicate the potential diagnostic applications of D-[¹⁸F]FDOPA for malignancies where the utility of L-[¹⁸F]FDOPA-PET is limited by the physiological uptake of L-[¹⁸F]FDOPA, and suggest D-[¹⁸F]FDOPA as a viable PET imaging tracer for NETs.

Patterns of Care Among Real-World Patients with Metastatic Neuroendocrine Tumors

BACKGROUND

Although recent pivotal trials (PROMID, CLARINET) have established somatostatin analogs (SSAs) as first-line agents for neuroendocrine tumors (NETs), their use in clinical practice is largely unknown. We aimed to understand real-world management and treatment of gastroenteropancreatic (GEP) NETs.

MATERIALS AND METHODS

Patients with metastatic GEP-NETs treated with SSAs, lanreotide depot or octreotide long-acting release (LAR), between January 1, 2015, and December 31, 2015, were identified from a U.S. claims database supplemented with chart review for a subset of patients. Descriptive statistics summarized patients' demographics, clinical characteristics, treatment patterns, and healthcare resource use. Univariate and multivariate comparisons were made across SSA groups.

RESULTS

Among 548 patients treated with an SSA for metastatic GEP-NET (lanreotide = 108; octreotide = 440), demographic and clinical characteristics were similar across groups, except more patients with pancreatic NETs were treated with lanreotide (38.7% vs. 6.3%, p < .01). More octreotide patients had a diagnosis of carcinoid syndrome compared with lanreotide patients (19.8% vs. 11.1%, p = .02). Approximately 1.1% of patients received lanreotide (>120 mg every 4 weeks [Q4W]) at a dose above label compared with 12.7% of octreotide patients (>30 mg Q4W; p < .01). At 1.5 years after SSA initiation, 85.7% (95% confidence interval, 74.3%-92.3%) were still on index SSA as reported by the physician. Variances between chart review and claims data were significant.

CONCLUSION

SSAs were common in first-line systemic intervention, but dose escalations and dosing deviations outside of label were noted. Variances between claims and chart review warrant additional research to compare methodologies. With an increasing focus on value-based care in oncology, it is critical to understand the use of, and outcomes with, these agents in community practices.

IMPLICATIONS FOR PRACTICE

The aim of this study was to enhance understanding of real-world management and treatment of metastatic neuroendocrine tumors (NETs), with particular focus on systemic therapy with a somatostatin analog (SSA). As per published guidelines, SSAs are common in first-line systemic intervention, but dose escalations and dosing deviations outside of the label are noted for symptom control. Nevertheless, oncologists must weigh the implications of the use of above-label dosing of SSAs to manage and treat patients with metastatic NET within a value-based care framework.

Effects of Ketoconazole on ACTH-Producing and Non-ACTH-Producing Neuroendocrine Tumor Cells

Prolonged remission of hypercortisolism with steroidogenesis inhibitors has been described in patients with ectopic adrenocorticotropic hormone (ACTH) syndrome. The anti-proliferative and pro-apoptotic effect of ketoconazole in human cancer cells was previously suggested. The aim of this study was to explore the effects of ketoconazole on ACTH-producing and non-ACTH-producing neuroendocrine tumor (NET) cell lines. The effects of ketoconazole alone, and in combination with somatostatin analogs, were evaluated in two human cell lines: DMS-79 (ectopic ACTH-producing small cell lung carcinoma) and BON-1 (human pancreatic NET). Total DNA measurement, apoptosis, cell cycle, chromogranin A (CgA)/proopiomelanocortin (POMC) expression by qRT-PCR, serotonin, CgA, and ACTH secretion assays were performed. In both cell lines, ketoconazole significantly suppressed cell growth and colony formation in a dose and time-dependent manner. The effect in DMS-79 was primarily cytotoxic, while it was more apoptotic in BON-1 cells. Ketoconazole also induced increase in G0/G1 phase in both cell lines and arrest in phase G2/M of BON-1 cells. Ketoconazole did not affect the secretion of serotonin, CgA, ACTH, or the mRNA expression of CgA and POMC. Decreased serotonin secretion was observed after the combination treatment with pasireotide. These results suggest a direct effect of ketoconazole on cell proliferation, apoptosis, and cell cycle in both ACTH- and non-ACTH-producing NET cells.

Specific Targeting of Somatostatin Receptor Subtype-2 for Fluorescence-Guided Surgery

PURPOSE

Clinically available intraoperative imaging tools to assist surgeons in identifying occult lesions are limited and partially responsible for the high rate of disease recurrence in patients with neuroendocrine tumors (NET). Using the established clinical efficacy of radiolabeled somatostatin analogs as a model, we demonstrate the ability of a fluorescent somatostatin analog to selectively target tumors that overexpress somatostatin receptor subtype-2 (SSTR2) and demonstrate utility for fluorescence-guided surgery (FGS).

EXPERIMENTAL DESIGN

A multimodality chelator (MMC) was used as a "radioactive linker" to synthesize the fluorescently labeled somatostatin analog, ^67/68Ga-MMC(IR800)-TOC. In vivo studies were performed to determine the pharmacokinetic profile, optimal imaging time point, and specificity for SSTR2-expressing tissues. Meso- and microscopic imaging of resected tissues and frozen sections were also performed to further assess specific binding, and binding to human NETs was examined using surgical biospecimens from patients with pancreatic NETs.

RESULTS

Direct labeling with ⁶⁷Ga/⁶⁸Ga provided quantitative biodistribution analysis that was in agreement with fluorescence data. Receptor-mediated uptake was observed in vivo and ex vivo at the macro-, meso-, and microscopic scales. Surgical biospecimens from patients with pancreatic NETs also displayed receptor-specific agent binding, allowing clear delineation of tumor boundaries that matched pathology findings.

CONCLUSIONS

The radioactive utility of the MMC allowed us to validate the binding properties of a novel FGS agent that could have a broad impact on cancer outcomes by equipping surgeons with real-time intraoperative imaging capabilities.

Metformin Use Is Associated With Longer Progression-Free Survival of Patients With Diabetes and Pancreatic Neuroendocrine Tumors Receiving Everolimus and/or Somatostatin Analogues

BACKGROUND & AIMS

Metformin seems to have anticancer effects. However, it is not clear whether use of glycemia and metformin affect outcomes of patients with advanced pancreatic neuroendocrine tumors (pNETs). We investigated the association between glycemia and progression-free survival (PFS) of patients with pNETs treated with everolimus and/or somatostatin analogues, as well as the association between metformin use and PFS time.

METHODS

We performed a retrospective analysis of 445 patients with advanced pNET treated at 24 medical centers in Italy from 1999 through 2015. Data on levels of glycemia were collected at time of diagnosis of pNET, before treatment initiation, and during treatment with everolimus (with or without somatostatin analogues), octreotide, or lanreotide. Diabetes was defined as prior or current use of glycemia control medication and/or fasting plasma glucose level ≥ 126 mg/dL, hemoglobin A1c ≥ 6.5% (48 mmol/L), or a random sample of plasma glucose ≥ 200 mg/dL (11.1 mmol/L), with reported classic symptoms of hyperglycemia or hyperglycemic crisis. Patients were assigned to groups based on diagnosis of diabetes before or during antitumor therapy. PFS was compared between patients with vs without diabetes. Among patients with diabetes, the association between metformin use and PFS was assessed. We performed sensitivity and landmark analyses to exclude patients who developed diabetes while receiving cancer treatment and to exclude a potential immortal time bias related to metformin intake.

RESULTS

PFS was significantly longer in patients with diabetes (median, 32.0 months) than without diabetes (median, 15.1 months) (hazard ratio for patients with vs without diabetes, 0.63; 95% confidence interval, 0.50-0.80; P = .0002). PFS of patients treated with metformin was significantly longer (median PFS, 44.2 months) than for patients without diabetes (hazard ratio for survival of patients with diabetes receiving metformin vs without diabetes, 0.45; 95% confidence interval, 0.32-0.62; P < .00001) and longer than for patients with diabetes receiving other treatments (median PFS, 20.8 months; hazard ratio, 0.49; 95% confidence interval, 0.34-0.69; P < .0001). In multivariable analysis, adjusted for other factors associated with outcomes, metformin was associated with longer PFS but level of glycemia was not. Metformin was associated with increased PFS of patients receiving somatostatin analogues and in those receiving everolimus, with or without somatostatin analogues. Sensitivity and landmark analyses produced similar results.

CONCLUSIONS

In a retrospective study of patients with pNETs, we found a significant association between metformin use and longer PFS.

The Clinicopathological Aspects of Primary Presacral Neuroendocrine Neoplasms: One Center Experience

OBJECTIVES

Presacral neuroendocrine neoplasms (NENs) are rare entities that are found at the presacral space. We report our experience in the diagnosis, management, and outcomes of primary presacral NENs.

METHODS

This was an institutional review board-approved retrospective review of medical records and surgical pathology specimens of patients with a diagnosis of NENs at Cedars-Sinai Medical Center between January 2000 and April 2016.

RESULTS

Ten patients were identified. The median age at presentation was 38 years (range, 20-77 years), and 8 were women. One patient presented with carcinoid-like symptoms, 2 were diagnosed incidentally, and 7 presented with symptoms related to mass effect. The median size of the tumor was 7.0 cm (range, 3-12 cm). On pathologic review, 3 of 10 were low-grade and well-differentiated, 5 of 10 were intermediate-grade and well-differentiated, 2 of 10 were grade 3 and classified as high-grade and poorly differentiated neuroendocrine tumors. Seven cases were metastatic on presentation with lymph node, liver, lung, or skeletal metastasis. Seven of 8 cases were detectable using Octreoscan. Eight patients were treated with a somatostatin analog and 5 patients were treated surgically.

CONCLUSIONS

Presacral NENs are clinically similar to gastroenteropancreatic tumors. Octreoscan imaging and somatostatin analog therapies were frequently applied. Further biologic characterization of this rare subtype is needed.

Nothing But NET: A Review of Neuroendocrine Tumors and Carcinomas

This review covers the diverse topic of neuroendocrine neoplasms (NENs), a relatively rare and heterogeneous tumor type, comprising ~2% of all malignancies, with a prevalence of <200,000 in the United States, which makes it an orphan disease (Basu et al., 2010).1 For functional purposes, NENs are divided into two groups on the basis of clinical behavior, histology, and proliferation rate: well differentiated (low grade to intermediate grade) neuroendocrine tumors and poorly differentiated (high grade) neuroendocrine carcinoma (Bosman et al., 2010)2; this histological categorization/dichotomization is highly clinically relevant with respect to impact on treatment and prognosis even though it is not absolute since a subset of tumors with a low-grade appearance behaves similarly to high-grade lesions. Given the relative dearth of evidenced-based literature about this orphan disease as a whole (Modlin et al., 2008),3 since the focus of most articles is on particular anatomic subtypes of NENs (i.e., gastroenteropancreatic or pulmonary), the purpose of this review is to summarize the presentation, pathophysiology, staging, current standard of care treatments, and active areas of current research.

Lymph node ratio, but not the total number of examined lymph nodes or lymph node metastasis, is a predictor of overall survival for pancreatic neuroendocrine neoplasms after surgical resection

Aim

To evaluate the prognostic significance of lymph node metastasis, extent of examined lymph nodes (ELNs) and lymph node ratio (LNR) for resected pancreatic neuroendocrine neoplasms (pNENs).

Materials and Methods

Surgically resected pNENs were assimilated from the Surveillance, Epidemiology, and End Results database. Kaplan-Meier and Cox proportional hazard models were used to examine the prognostic effect of clinicopathological characteristics on overall survival; Harrell's concordance index was performed to assess the prognostic accuracy of all independent prognostic factors; and the Spearman's rank correlation was used to assess the correlation between LNR and other clinicopathological characteristics.

Results

Totally, 1,273 pathologically confirmed pNENs were included in our study. The extent of ELNs failed to show any survival benefit in entire cohort (ELNs ≤ 12 vs. ELNs > 12, P = 0.072) or pNENs without lymph node metastasis (ELNs ≤ 28 vs. ELNs > 28, P = 0.108). Lymph node metastasis and LNR > 0.40 were significantly (both P < 0.001) adverse prognostic factors of overall survival. However, only LNR > 0.40 was the independent predictor of survival after adjusted for other clinicopathological characteristics. Besides LNR, the age, gender, primary tumor site, grade and stage also were the independent predictors of overall survival; and this survival model had an acceptable predictive power (Harrell's concordance index, 0.731).

Conclusions

The current study suggested that the LNR, not the total number of ELNs and the lymph node metastasis, is an independent prognostic indicator of overall survival for pNENs after surgical resection.

Efficacy of everolimus plus octreotide LAR in patients with advanced neuroendocrine tumor and carcinoid syndrome: final overall survival from the randomized, placebo-controlled phase 3 RADIANT-2 study

Background

In the phase 3 RADIANT-2 study, everolimus plus octreotide long-acting repeatable (LAR) showed improvement of 5.1 months in median progression-free survival versus placebo plus octreotide LAR among patients with advanced neuroendocrine tumors associated with carcinoid syndrome. The progression-free survival P-value was marginally above the prespecified threshold for statistical significance. Here, we report final overall survival (OS) and key safety update from RADIANT-2.

Patients and methods

The RADIANT-2 trial compared everolimus (10 mg/day, orally; n = 216) versus placebo (n = 213), both in conjunction with octreotide LAR (30 mg, intramuscularly, every 28 days). Patients, unblinded at the time of progression or after end of double-blind core phase following primary analysis, were offered open-label everolimus with octreotide LAR (open-label phase). In the open-label phase, patients had similar safety and efficacy assessments as those in the core phase. For OS, hazard ratios (HRs) with 95% CIs using unadjusted Cox model and a Cox model adjusted for prespecified baseline covariates were calculated.

Results

A total of 170 patients received open-label everolimus (143 crossed over from the placebo arm; 27 in the everolimus arm continued to receive the same treatment after unblinding). The median OS (95% CI) after 271 events was 29.2 months (23.8-35.9) for the everolimus arm and 35.2 months (30.0-44.7) for the placebo arm (HR, 1.17; 95% CI, 0.92-1.49). HR adjusted for baseline covariates was 1.08 (95% CI, 0.84-1.38). The most frequent drug-related grade 3 or 4 AEs reported during the open-label phase were diarrhea (5.3%), fatigue (4.7%), and stomatitis (4.1%). Deaths related to pulmonary or cardiac failure were observed more frequently in the everolimus arm.

Conclusion

No significant difference in OS was observed for the everolimus plus octreotide LAR and placebo plus octreotide LAR arms of the RADIANT-2 study, even after adjusting for imbalances in the baseline covariates.

Clinical Trial Number

NCT00412061, www.clinicaltrials.gov.

Is estrogen exposure a protective factor for pancreatic neuroendocrine tumours in female patients with multiple endocrine neoplasia syndrome type 1?

OBJECTIVE

Pancreatic neuroendocrine tumours (PNETs) are the most common cause of death in patients with multiple endocrine neoplasia type 1 (MEN1). Women have been shown to have improved survival, which may suggest a possible protective effect of female sex hormones. The aim of this study was to evaluate the relationship between estrogen exposure and PNET tumourigenesis, tumour growth and survival in female MEN1 patients with these tumours.

DESIGN

We performed a retrospective chart review of the existing MEN1 database in our institution. Detailed information about female patients' menstrual and reproductive history, and PNET clinicopathologic characteristics was collected. Questionnaires regarding estrogen exposure were used to collect information that was missing in the database.

PATIENTS

Of 293 confirmed MEN1 cases, 141 women met the inclusion criteria.

MEASUREMENTS

We used measures of cumulative estrogen exposure time (CEET), parity, live birth pregnancies and bilateral oophorectomy to estimate estrogen exposure.

RESULTS

There was no significant association between CEET and time to PNET diagnosis (hazard ratio = 0·966, P = 0·380). For the correlation between estrogen exposure and PNET type, size, numbers, distant metastasis, lymph node metastasis, lymphovascular invasion, AJCC (American Joint Committee on Cancer) stage and overall survival, only CEET was significantly correlated with PNET size (P = 0·043).

CONCLUSIONS

In female patients with MEN1, estrogen exposure may inhibit PNET growth. A demonstrable protective effect against PNET tumourigenesis, tumour growth and survival of patients with these tumours may require a larger cohort.

Menin and Daxx Interact to Suppress Neuroendocrine Tumors through Epigenetic Control of the Membrane Metallo-Endopeptidase

Neuroendocrine tumors (NET) often harbor loss-of-function mutations in the MEN1 and DAXX tumor suppressor genes. Here, we report that the products of these genes, menin and Daxx, interact directly with each other to suppress the proliferation of NET cells, to a large degree by inhibiting expression of the membrane metallo-endopeptidase (MME). Menin and Daxx were required to enhance histone H3 lysine9 trimethylation (H3K9me3) at the MME promoter, as mediated partly by the histone H3 methyltransferase SUV39H1. Notably, the menin T429K mutation associated with a NET syndrome reduced Daxx binding, MME repression, and proliferation of NET cells. Conversely, inhibition of MME in NET cells repressed proliferation and tumor growth in vivo Our findings reveal a previously unappreciated cross-talk between two crucial tumor suppressor genes thought to work by independent pathways, focusing on MME as a common target of menin/Daxx to treat NET. Cancer Res; 77(2); 401-11. ©2016 AACR.

Cell Cycle Protein Expression in Neuroendocrine Tumors: Association of CDK4/CDK6, CCND1, and Phosphorylated Retinoblastoma Protein With Proliferative Index

OBJECTIVES

Dysregulation of the cell cycle has been observed and implicated as an etiologic factor in a range of human malignancies, but remains relatively unstudied in neuroendocrine tumors (NETs). We evaluated expression of key proteins involved in cell cycle regulation in a large cohort of NETs.

METHODS

We evaluated immunohistochemical expression of CDKN1B, CDKN1A, CDKN2A, CDK2, CDK4, CDK6, cyclin D1, cyclin E1, and phosphorylated retinoblastoma protein (phospho-RB1) in a cohort of 267 patients with NETs. We then explored associations between cell cycle protein expression, mutational status, histologic features, and overall survival.

RESULTS

We found that high expression of CDK4, CDK6, CCND1, and phospho-RB1 was associated with higher proliferative index, as defined by MKI67. We additionally observed a trend toward shorter overall survival associated with low expression of CDKN1B. This association seemed strongest in SINETs (multivariate hazards ratio, 2.04; 95% confidence interval, 1.06-3.93; P = 0.03). We found no clear association between CDKN1B mutation and protein expression.

CONCLUSIONS

Our results suggest that dysregulation and activation of the CDK4/CDK6-CCND1-phospho-RB1 axis is associated with higher proliferative index in NETs. Investigation of the therapeutic potential of CDK4/CDK6 inhibitors in higher grade NETs is warranted.

Somatostatin analogues in acromegaly and gastroenteropancreatic neuroendocrine tumours: past, present and future

Acromegaly is a hormonal disorder that arises when the pituitary gland secretes excess growth hormone (GH), which in turn stimulates a concomitant increase in serum insulin-like growth factor 1 (IGF-1) levels. Gastroenteropancreatic neuroendocrine tumours (GEP-NET) constitute a heterogeneous group of tumours that can secrete serotonin and a variety of peptide hormones that may cause characteristic symptoms known as carcinoid syndrome or other symptoms and hormonal hypersecretion syndromes depending on the tumour's site of origin. Current medical therapy for the treatment of acromegaly and GEP-NET involves the administration of somatostatin analogues that effectively suppress excess hormone secretion. After its discovery in 1979, octreotide became the first synthetic biologically stable somatostatin analogue with a short-acting formulation of octreotide introduced into clinical practice in the late 1980s. Lanreotide, another somatostatin analogue, became available in the mid-1990s initially as a prolonged-release formulation administered every 10 or 14 days. Long-acting release formulations of both octreotide (Sandostatin LAR and Novartis) and lanreotide (Somatuline Autogel, Ipsen), based on microparticle and nanoparticle drug-delivery technologies, respectively, were later developed, which allowed for once-monthly administration and improved convenience. First-generation somatostatin analogues remain one of the cornerstones of medical therapy in the management of pituitary and GEP-NET hormone hypersecretion, with octreotide having the longest established efficacy and safety profile of the somatostatin analogue class. More recently, pasireotide (Signifor), a next-generation multireceptor-targeted somatostatin analogue, has emerged as an alternative therapeutic option for the treatment of acromegaly. This review summarizes the development and clinical success of somatostatin analogues.

Management of controversial gastroenteropancreatic neuroendocrine tumour clinical situations with somatostatin analogues: results of a Delphi questionnaire panel from the NETPraxis program

BACKGROUND

There are clinical situations (CS) in which the use of somatostatin analogs (SSAs) in patients with neuroendocrine tumors (NET) is controversial due to lack of evidence. A Delphi study was conducted to develop common treatment guidelines for these CS, based on clinical practice and expert opinion of Spanish oncologists.

METHODS

A scientific committee identified 5 CS with a common core (c-c) [non-functioning NET, not susceptible of surgery/locoregional therapy, Ki67 < 10 % (except for CS5: >10 %), ECOG ≤ 2], and controversy regarding use of SSAs, and prepared a Delphi questionnaire of 48 treatment statements. Statements were rated on a 1 (completely disagree) to 9 (completely agree) scale. Responses were grouped by tertiles: 1-3: Disagreement, 4-6: Neutral, 7-9: Agreement. Consensus was reached when the responses of ≥2/3 participants were located in the same tertile as the median value of all reported responses for that statement.

RESULTS

Sixty five (81.2 %) of 80 invited oncologists with experience in the management of NETs answered a first round of the questionnaire and 57 (87.7 %) of those 65 answered a second round (mean age 43.5 years; 53.8 % women; median time of experience 9 years). Consensus was obtained in 42 (36 agreement and 6 disagreement) of the 48 statements (87.5 %). Regarding CS1 (Enteropancreatic NET, c-c, non-progressive in the last 3-6 months), overall, SSA treatment is recommended (a wait and see approach is anecdotal and reserved for fragile patients or with low tumor load or ki-67 < 2 %); CS2 (Pancreatic NET, c-c), overall, SSA monotherapy is recommended, except when high tumor load or tumor progression exists, where combination therapy would be considered; CS3 [Gastroenteropancreatic (GEP)-NET, c-c, in treatment with anti-proliferative dose of SSA and progressing], overall, SSA maintenance is recommended at the time of progression, with or without adding molecular targeted drugs; CS4 (GEP-NET, c-c, and negative octreoscan®), SSA in monotherapy is only considered in low-risk patients (low tumor load and Ki-67 < 5 %); CS5 [GEP-NET, c-c (ki67 > 10 %), and positive octreoscan®], monotherapy with SSA is mainly considered in patients with comorbidities.

CONCLUSION

Several recommendations regarding use of SSAs in controversial NET CS were reached in consensus and might be considered as treatment guideline.

A Delphic consensus assessment: imaging and biomarkers in gastroenteropancreatic neuroendocrine tumor disease management

The complexity of the clinical management of neuroendocrine neoplasia (NEN) is exacerbated by limitations in imaging modalities and a paucity of clinically useful biomarkers. Limitations in currently available imaging modalities reflect difficulties in measuring an intrinsically indolent disease, resolution inadequacies and inter-/intra-facility device variability and that RECIST (Response Evaluation Criteria in Solid Tumors) criteria are not optimal for NEN. Limitations of currently used biomarkers are that they are secretory biomarkers (chromogranin A, serotonin, neuron-specific enolase and pancreastatin); monoanalyte measurements; and lack sensitivity, specificity and predictive capacity. None of them meet the NIH metrics for clinical usage. A multinational, multidisciplinary Delphi consensus meeting of NEN experts (n = 33) assessed current imaging strategies and biomarkers in NEN management. Consensus (>75%) was achieved for 78% of the 142 questions. The panel concluded that morphological imaging has a diagnostic value. However, both imaging and current single-analyte biomarkers exhibit substantial limitations in measuring the disease status and predicting the therapeutic efficacy. RECIST remains suboptimal as a metric. A critical unmet need is the development of a clinico-biological tool to provide enhanced information regarding precise disease status and treatment response. The group considered that circulating RNA was better than current general NEN biomarkers and preliminary clinical data were considered promising. It was resolved that circulating multianalyte mRNA (NETest) had clinical utility in both diagnosis and monitoring disease status and therapeutic efficacy. Overall, it was concluded that a combination of tumor spatial and functional imaging with circulating transcripts (mRNA) would represent the future strategy for real-time monitoring of disease progress and therapeutic efficacy.

NETs: organ-related epigenetic derangements and potential clinical applications

High-throughput next-generation sequencing methods have recently provided a detailed picture of the genetic landscape of neuroendocrine tumors (NETs), revealing recurrent mutations of chromatin-remodeling genes and little-to-no pathogenetic role for oncogenes commonly mutated in cancer. Concurrently, multiple epigenetic modifications have been described across the whole spectrum of NETs, and their putative function as tumorigenic drivers has been envisaged. As result, it is still unclear whether or not NETs are epigenetically-driven, rather than genetically-induced malignancies. Although the NET epigenome profiling has led to the identification of molecularly-distinct tumor subsets, validation studies in larger cohorts of patients are needed to translate the use of NET epitypes in clinical practice. In the precision medicine era, recognition of subpopulations of patients more likely to respond to therapeutic agents is critical, and future studies testing epigenetic biomarkers are therefore awaited. Restoration of the aberrant chromatin remodeling machinery is an attractive approach for future treatment of cancer and in several hematological malignancies a few epigenetic agents have been already approved. Although clinical outcomes of epigenetic therapies in NETs have been disappointing so far, further clinical trials are required to investigate the efficacy of these drugs. In this context, given the immune-stimulating effects of epidrugs, combination therapies with immune checkpoint inhibitors should be tested. In this review, we provide an overview of the epigenetic changes in both hereditary and sporadic NETs of the gastroenteropancreatic and bronchial tract, focusing on their diagnostic, prognostic and therapeutic implications.

Role of targeted agents in neuroendocrine tumors: Results from a meta-analysis

BACKGROUND

Several randomized phase III trials in neuroendocrine tumors (NETs) showed the clinical role of new targeted agents and their impact on tumor response and outcome of whose patients affected by advanced NET. In this study, we summarize the available clinical data related to clinical efficacy of targeted therapies in the treatment of advanced NETs.

METHODS

A meta-analysis of randomized studies in accordance with the PRISMA guidelines was performed after searching the databases of PubMed, the Cochrane Library, and the ASCO University Meeting for relevant publications.

RESULTS

One thousand 9 hundred and 8 cases were included in the meta-analysis; among these, 1012 were in the experimental arm and 896 were in the control arm. The pooled analysis of the use of target agents in NETs revealed significantly increased of progression free survival compared to control group (hazard ratio = 0.59, 95% CI:0.42-0.84; P = 0.003). Subgroup analysis of patients according to tumor site showed a difference in favor of pancreatic neuroendocrine tumors. Moreover, targeted therapies improved the overall survival (hazard ratio = 0.79, 95%CI: 0.63-0.98; P = 0.03), and response rate (hazard ratio = 3.33, 95% CI 2.02-5.49; P < 0.00001) in all types of NETs.

CONCLUSION

Our analysis supports the routine use of targeted agents for treatment of neuroendocrine tumors with particular regards to the pancreatic neuroendocrine tumors.

A Phase II Trial of a Histone Deacetylase Inhibitor Panobinostat in Patients With Low-Grade Neuroendocrine Tumors

Lessons Learned

Background.

The most common subtypes of neuroendocrine tumors (NETs) are pancreatic islet cell tumors and carcinoids, which represent only 2% of all gastrointestinal malignancies. Histone deacetylase (HDAC) inhibitors have already been shown to suppress tumor growth and induce apoptosis in various malignancies. In NET cells, HDAC inhibitors have resulted in increased Notch1 expression and subsequent inhibition of growth. We present here a phase II study of the novel HDAC inhibitor panobinostat in patients with low-grade NET.

Methods.

Adult patients with histologically confirmed, metastatic, low-grade NETs and an Eastern Cooperative Oncology Group (ECOG) performance status of ≤2 were treated with oral panobinostat 20 mg once daily three times per week. Treatment was continued until patients experienced unacceptable toxicities or disease progression. The study was stopped at planned interim analysis based on a Simon two-stage design.

Results.

Fifteen patients were accrued, and 13 were evaluable for response. No responses were seen, but the stable disease rate was 100%. The median progression-free survival (PFS) was 9.9 months, and the median overall survival was 47.3 months. Fatigue (27%), thrombocytopenia (20%), diarrhea (13%), and nausea (13%) were the most common related grade 3 toxicities. There was one grade 4 thrombocytopenia (7%). These results did not meet the prespecified criteria to open the study to full accrual.

Conclusion.

The HDAC inhibitor panobinostat has a high stable disease rate and reasonable PFS in low-grade NET, but has a low response rate.

Diagnosis and management of gastrointestinal neuroendocrine tumors: An evidence-based Canadian consensus

The majority of neuroendocrine tumors originate in the digestive system and incidence is increasing within Canada and globally. Due to rapidly evolving evidence related to diagnosis and clinical management, updated guidance on the diagnosis and treatment of gastrointestinal neuroendocrine tumors (GI-NETs) are of clinical importance. Well-differentiated GI-NETs may exhibit indolent clinical behavior and are often metastatic at diagnosis. Some NET patients will develop secretory disease requiring symptom control to optimize quality of life and clinical outcomes. Optimal management of GI-NETs is in a multidisciplinary environment and is multimodal, requiring collaboration between medical, surgical, imaging and pathology specialties. Clinical application of advances in pathological classification and diagnostic technologies, along with evolving surgical, radiotherapeutic and medical therapies are critical to the advancement of patient care. We performed a systematic literature search to update our last set of published guidelines (2010) and identified new level 1 evidence for novel therapies, including telotristat etiprate (TELESTAR), lanreotide (CLARINET), everolimus (RADIANT-2; RADIANT-4) and peptide receptor radionuclide therapy (PRRT; NETTER-1). Integrating these data with the clinical knowledge of 16 multi-disciplinary experts, we devised consensus recommendations to guide state of the art clinical management of GI-NETs.

Metformin with everolimus and octreotide in pancreatic neuroendocrine tumor patients with diabetes

A bidirectional relationship seems to exist between diabetes mellitus and development of pancreatic tumors. Metformin, the most widely used drug in the treatment of Type 2 diabetes mellitus, has recently emerged as a potentially active agent in cancer chemoprevention and treatment. In this article, we discuss the potential correlation between glycemic status, administration of antiglycemic treatments, such as metformin or insulin, and prognosis of pancreatic neuroendocrine tumors patients treated with everolimus and octreotide, on the basis of existing evidence and our experience.

(68)Ga-DOTATOC PET and gene expression profile in patients with neuroendocrine carcinomas: strong correlation between PET tracer uptake and gene expression of somatostatin receptor subtype 2

Somatostatin receptor expression on both protein and gene expression level was compared with in vivo (68)Ga-DOTATOC PET/CT in patients with neuroendocrine carcinomas (NEC). Twenty-one patients with verified NEC who underwent a (68)Ga-DOTATOC PET/CT between November 2012 and May 2014, were retrospectively included. By real-time polymerase chain reaction, we quantitatively determined the gene expression of several genes and compared with (68)Ga-DOTATOC PET uptake. By immunohistochemistry we qualitatively studied the expression of assorted proteins in NEC. The median age at diagnosis was 68 years (range 41-84) years. All patients had WHO performance status 0-1. Median Ki67 index was 50% (range 20-100%). Gene expression of somatostatin receptor subtype (SSTR) 2 and Ki67 were both positively correlated to the (68)Ga-DOTATOC uptake (r=0.89; p<0.0001 and r=0.5; p=0.021, respectively). Furthermore, SSTR2 and SSTR5 gene expression were strongly and positively correlated (r=0.57; p=0.006). This study as the first verifies a positive and close correlation of (68)Ga-DOTATOC uptake and gene expression of SSTR2 in NEC. SSTR2 gene expression has a stronger correlation to (68)Ga-DOTATOC uptake than SSTR5. In addition, the results indicate that the gene expression levels of SSTR2 and SSTR5 at large follow one another.

Decoding the Molecular and Mutational Ambiguities of Gastroenteropancreatic Neuroendocrine Neoplasm Pathobiology

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NEN), considered a heterogeneous neoplasia, exhibit ill-defined pathobiology and protean symptomatology and are ubiquitous in location. They are difficult to diagnose, challenging to manage, and outcome depends on cell type, secretory product, histopathologic grading, and organ of origin. A morphologic and molecular genomic review of these lesions highlights tumor characteristics that can be used clinically, such as somatostatin-receptor expression, and confirms features that set them outside the standard neoplasia paradigm. Their unique pathobiology is useful for developing diagnostics using somatostatin-receptor targeted imaging or uptake of radiolabeled amino acids specific to secretory products or metabolism. Therapy has evolved via targeting of protein kinase B signaling or somatostatin receptors with drugs or isotopes (peptide-receptor radiotherapy). With DNA sequencing, rarely identified activating mutations confirm that tumor suppressor genes are relevant. Genomic approaches focusing on cancer-associated genes and signaling pathways likely will remain uninformative. Their uniquely dissimilar molecular profiles mean individual tumors are unlikely to be easily or uniformly targeted by therapeutics currently linked to standard cancer genetic paradigms. The prevalence of menin mutations in pancreatic NEN and P27^KIP1 mutations in small intestinal NEN represents initial steps to identifying a regulatory commonality in GEP-NEN. Transcriptional profiling and network-based analyses may define the cellular toolkit. Multianalyte diagnostic tools facilitate more accurate molecular pathologic delineations of NEN for assessing prognosis and identifying strategies for individualized patient treatment. GEP-NEN remain unique, poorly understood entities, and insight into their pathobiology and molecular mechanisms of growth and metastasis will help identify the diagnostic and therapeutic weaknesses of this neoplasia.

Survival analysis and prognostic factors for neuroendocrine tumors in Turkey

BACKGROUND

This study aimed to determine the demographical distribution, survival and prognostic factors for neuroendocrine tumors monitored in our clinic.

MATERIALS AND METHODS

Data for 52 patients who were admitted to Cumhuriyet University Medical Faculty Training Research and Practice Hospital Oncology Center between 2006 and 2012 and were diagnosed and treated for neuroendocrine tumors were investigated.

RESULTS

Of the total, 30 (58%) were females and 22 (42%) were males. The localization of the disease was gastroenteropancreatic in 29 (56%) patients and other sites in 23 (44%). The most frequently involved organ in the gastroenteropancreatic system was the stomach (n=10, 19%) and the most frequently involved organ in other regions was the lungs (n=10, 19%). No correlation was found between immunohistochemical staining for proteins such as chromogranin A, synaptophysin, and NSE and the grade of the tumor. The patients were followed-up at a median of 24 months (1-90 months). The three-year overall survival rate was 71%: 100% in stage I, 88% in stage II, 80% in stage III, and 40% in stage IV. The three-year survival rate was 78% in tumors localized in the gastroenteropancreatic region, and 54% in tumors localized in other organs. In the univariate analysis, gender, age, performance status of the patients, grade, localization, surgical treatment, and neutrophil/ lymphocyte ratio (≤ 5 versus >5) affected the prognosis of the patients.

CONCLUSIONS

Most of the tumors were localized in the gastroenteropancreatic region, and the three-year survival rate in tumors localized in this region was better than the tumors localized in other sites. Surgical treatment was a positive independent prognostic factor, whereas Grade 3 and a neutrophil/lymphocyte ratio of >5 were negative independent prognostic factors.

Catheter-based treatments for hepatic metastases from neuroendocrine tumors

OBJECTIVE

The purpose of this article is to present our experience in treating patients with hepatic metastases from a neuroendocrine primary malignancy.

CONCLUSION

The tumor and patient characteristics, vascular access, and features of treatment all play a role in the long-term management of patients with metatastic neuroendocrine tumors. Routine prophylactic measures are recommended to reduce the frequency and severity of crisis events related to hormone release in patients with neuroendocrine tumors.

Expression of estrogen-induced genes and estrogen receptor β in pancreatic neuroendocrine tumors: implications for targeted therapy

OBJECTIVE

The indolent nature and expression of progesterone receptor (PR), a well-known estrogen-induced gene, in a subset of pancreatic neuroendocrine tumors (PanNETs), raise the possibility of hormonal regulation in these tumors.

METHODS

Immunohistochemical expression of estrogen receptors (ERs) α and β as well as messenger RNA expression of estrogen-induced genes (PR, EIG121, IGF-1, IGF-1R, sFRP1, and sFRP4) by quantitative reverse transcription-polymerase chain reaction were examined in 131 World Health Organization grade G1 and G2 PanNETs and correlated their expression with clinicopathological features.

RESULTS

Thirty-nine PanNETs (30%) showed high positive ERβ staining, and 87 cases (66%) had low positive ERβ staining; only 5 cases (4%) had no nuclear staining. Pancreatic neuroendocrine tumors with small size (P = 0.02), low World Health Organization grade (P = 0.02), and low American Joint Committee on Cancer stage (P = 0.006) more frequently showed high positive ERβ staining. Among the estrogen-induced genes studied, PanNETs had significantly higher expression of PR, EIG121, IGF-1, sFRP1, and sFRP4 compared with normal pancreas, independent of age or sex. High positive ERβ staining was associated with an increased expression of PR (P < 0.001) and EIG121 (P = 0.02).

CONCLUSIONS

Our study showed that PanNETs with favorable prognostic features have higher ERβ expression, which is associated with up-regulated PR and EIG121 messenger RNA expression. Estrogen regulation in PanNETs could potentially help in risk stratification and provide a rational target for novel treatment strategies.

Real-world study of everolimus in advanced progressive neuroendocrine tumors

Everolimus is a valid therapeutic option for neuroendocrine tumors (NETs); however, data in a real-world setting outside regulatory trials are sparse. The aim of this study was to determine everolimus tolerability and efficacy, in relation to previous treatments, in a compassionate use program. A total of 169 patients with advanced progressive NETs treated with everolimus were enrolled, including 85 with pancreatic NETs (pNETs) and 84 with nonpancreatic NETs (non-pNETs). Previous treatments included somatostatin analogs (92.9%), peptide receptor radionuclide therapy (PRRT; 50.3%), chemotherapy (49.7%), and PRRT and chemotherapy (22.8%). Overall, 85.2% of patients experienced adverse events (AEs), which were severe (grade 3-4) in 46.1%. The most frequent severe AEs were pneumonitis (8.3%), thrombocytopenia (7.7%), anemia (5.3%), and renal failure (3.5%). In patients previously treated with PRRT and chemotherapy, a 12-fold increased risk for severe toxicity was observed, with grade 3-4 AEs reported in 86.8% (vs. 34.3% in other patients). In addition, 63.3% of patients required temporarily everolimus discontinuation due to toxicity. Overall, 27.8% of patients died during a median follow-up of 12 months. Median progression-free survival (PFS) and overall survival (OS) were 12 months and 32 months, respectively. Similar disease control rates, PFS, and OS were reported in pNETs and non-pNETs. In the real-world setting, everolimus is safe and effective for the treatment of NETs of different origins. Higher severe toxicity occurred in patients previously treated with systemic chemotherapy and PRRT. This finding prompts caution when using this drug in pretreated patients and raises the issue of planning for everolimus before PRRT and chemotherapy in the therapeutic algorithm for advanced NETs.

Are Targeted Therapies a Consideration in Poorly Differentiated Neuroendocrine Tumors?

The close relationship between poorly differentiated NETs (PDNETs) and well or intermediately differentiated neuroendocrine tumors (NETs) is evidenced by the World Health Organization criteria for distinguishing these groups and by recognition by the National Comprehensive Cancer Network that octreotide therapy should be considered in some PDNETs. Based on the possible derivation from similar normal cells and the somewhat arbitrary World Health Organization distinction, particularly between intermediate and poorly differentiated NETs, it seems reasonable that future studies of targeted agents in the treatment of NETs should evaluate patients with PDNETs as well.

Pneumocystis pneumonia in everolimus therapy: An indistinguishable case from drug induced interstitial lung disease

A 66-year-old male treated with everolimus for renal cell carcinoma developed exertional dyspnea. Chest computed tomography revealed diffuse interstitial shadows on both lungs. Bronchoalveolar lavage and the drug-induced lymphocyte stimulation test confirmed the diagnosis of drug-induced interstitial lung disease due to everolimus therapy. However, discontinuation of everolimus in combination with corticosteroid therapy did not prevent disease progression. On the basis of a PCR assay for Pneumocystis jirovecii and elevated β-D-glucan levels, trimethoprim-sulfamethoxazole was administered immediately, resulting in a dramatic improvement. This case demonstrated that pneumocystis pneumonia should always be considered and treated during everolimus therapy, even when drug-induced interstitial lung disease is suspected.