Nonpancreatic Neuroendocrine Tumors Research Articles

Potential biomarkers for treatment response in advanced non-pancreatic neuroendocrine tumors.

599 Background: Well-differentiated NETs are highly vascular and hence, inhibition of angiogenesis is of interest. VEGF, a key molecule in promoting angiogenesis, has also been shown to promote an immunosuppressive tumor microenvironment. Nintedanib, an oral inhibitor of FGFR1–3, VEGFR1–3 and PDGFRA, has previously been evaluated in a phase II clinical trial in well-differentiated, non-pancreatic NETs, where 83% of the evaluable patients were progression-free at 16 weeks and median PFS was 11 months. In preclinical studies, nintedanib has been shown to increase PD-L1 expression in tumor cells, which then results in improved outcomes with immune checkpoint inhibition. There are multiple indicators of T-cell exhaustion, including PD-L1 and LAG-3. LAG-3+ T-cells have been found to correlate with poor response to treatment in neuroendocrine neoplasms. Given these findings, this study evaluates serum VEGF and LAG-3 expression to determine potential biomarkers of response in patients treated with nintedanib. Methods: 27 sets of paired samples collected at baseline and 8-weeks post treatment with nintedanib, from clinical trial NCT02399215 were used for this study. With IRB approval, we tested for serum VEGFa and serum LAG-3 using Luminex test kits: HCKP1-11K-01 (LAG-3) and HCYTA-60K-01 (VEGFa). We compared the baseline, 8-week, and percentage change in serum VEGF and serum LAG-3 levels with Rd Cd8+ pAkt+ T-cells (activated cytotoxic T-cells) as a marker of immune activation, Rd CD25+ pAkt+ T-cells (regulatory T-cells) as a marker of immune suppression, and PFS. Results: The median VEGF levels at baseline and 8-weeks were 10.50 pg/mL and 11.90 pg/mL respectively. The median LAG-3 level at baseline and 8-weeks were 59000 pg/mL and 62900 pg/mL respectively. Higher VEGFa levels in the post-treatment samples were associated with poorer progression free survival (HR= 1.009, 95% HR CI: [0.999, 1.019], with P= 0.0760). Higher levels of VEGF at baseline were also associated with lower numbers of Rd CD8+ pAkt + cells (Pearson coefficient = -0.42, p-value 0.04) at baseline. Increased baseline CD25+ pAkt+ levels were positively correlated with percent change in serum LAG-3 levels between baseline and post-treatment samples. (Pearson Co-efficient: 0.45; p=value: 0.02). Conclusions: Elevated serum VEGFa levels at 8-weeks post treatment correlated with lower PFS. Serum VEGFa level is a potential indicator of effector T-cell suppression, as evidenced by low number of activated cytotoxic T-cells in patients with higher VEGFa levels at baseline. Higher baseline regulatory T-cells were associated with a greater increase in serum LAG-3 levels, suggesting that serum LAG-3 may be an indicator of an immunosuppressive tumor microenvironment.

Islet-1 Is Differentially Expressed Among Neuroendocrine and Non-Neuroendocrine Tumors and Its Potential Diagnostic Implication.

Islet-1 (ISL1) plays key roles in programming the epigenome and facilitating the recruitment of additional regulatory factors. Although it has been used as a marker for pancreatic neuroendocrine tumors (PanNETs), ISL1 reactivity in other tumor types are critically missing. ISL1 immunohistochemistry was performed on 147 neuroendocrine tumors (NET) originated in pancreas, gastrointestinal tract, lung, thyroid, parathyroid, pituitary, adrenal medulla, head/neck, genitourinary tract, and skin; and 110 non-neuroendocrine tumors originated in the pancreas, thymus, lung, thyroid, mesothelium, adrenal cortex, stomach, breast, head/neck, skin, and kidney. ISL1 nuclear staining was observed in normal thymic epithelium, pancreatic islets, adrenal medulla, and pituitary gland cells as well as frequently in tumors of these origins: pancreatic NET (78%), paraganglioma/pheochromocytoma (100%), thymoma (82%), and pituitary NET (50%). ISL1 was also variably expressed in certain non-pancreatic NET such as Merkel cell carcinoma (100%), medullary carcinoma of the thyroid (100%), head/neck NEC (80%), genitourinary NEC (71%), lung small cell carcinoma (46%), lung carcinoids (17%), lower intestinal tract NET (93%) but not in upper gastrointestinal tract NET nor parathyroid adenoma. For other non-NETs, focal ISL1 expression was less frequently detected in gastric adenocarcinoma (40%), mesothelioma (29%), adrenal cortical carcinoma (17%), and squamous carcinoma (24%), but not in others tested. ISL1 is not a pan-NE marker as it is consistently lacking in upper gastrointestinal NET and parathyroid adenoma. It is also differentially expressed in thymoma. ISL1 immunohistochemnistry could help to differentiate PanNET and lower intestinal NET from upper gastrointestinal NET and be used as a marker for thymoma.

Efficacy and Toxicity Analysis of Capecitabine and Temozolomide in Neuroendocrine Neoplasms.

The capecitabine/temozolomide (CAPTEM) regimen has significant activity in advanced neuroendocrine tumors (NETs). Questions exist regarding activity in pancreatic versus nonpancreatic NETs, risk of opportunistic infections, long-term myelotoxicity, and safety of prolonged treatment duration. Analysis of large patient cohorts is needed for the evaluation of rare toxicities and assessment of risk factors. We conducted a retrospective study of all patients with advanced NETs seen at Moffitt Cancer Center between January 2008 and June 2019 who received treatment with CAPTEM. A total of 462 patients were eligible. The objective radiographic response rate was 46%, and the disease control rate was 81%. Median progression-free survival (PFS) was 18 months (95% CI, 14.0-21.9 months) and median overall survival was 51 months (95% CI, 42.8-59.2 months): 62 months in well-differentiated NETs versus 14 months in poorly differentiated neuroendocrine carcinomas (P<.0001). Patients with primary pancreatic tumors had the highest partial response rates and longest median PFS. Incidences of grade 4 thrombocytopenia and neutropenia were 7% and 3%, respectively, and substantially higher in women than men (P=.02 and P=.004, respectively). Only 1 case (0.2%) of suspected Pneumocystis pneumonia (PCP) was observed in a patient receiving corticosteroids. Three patients developed myelodysplastic disease, all of whom had received prior peptide receptor radiotherapy (PRRT). There were no acute treatment-related deaths; 1 patient died 2 months after a thrombocytopenic bleed. The CAPTEM regimen is exceptionally safe. Efficacy is particularly robust in well-differentiated pancreatic NETs. Severe myelotoxicity is rare; the risk of grade 4 cytopenias is significantly increased in women, and therefore sex-based dosing should be considered. There were no cases of myelodysplastic syndromes, except among patients who had received PRRT, a known risk factor. The risk of PCP is negligible.

74325 Vast sex-specific differences in transcriptional landscapes of pancreatic neuroendocrine tumors

ABSTRACT IMPACT: Here, we describe extensive sex-specific differences in the transcriptomes of pancreatic neuroendocrine tumors (PNETs). Given that the clinical course of PNETs differs by sex (female sex is associated with better survival), achieving a greater understanding of the specific molecular sexual dimorphisms is invaluable for advancing personalized treatment. OBJECTIVES/GOALS: Epidemiologic studies demonstrate that pancreatic neuroendocrine tumors (PNETs) exhibit sexual dimorphisms with regards to prognosis, disease recurrence, and complication rates. We sought to compare the transcription and DNA methylation landscapes of PNETs by sex, to elucidate molecular differences that may underlie this sex disparity. METHODS/STUDY POPULATION: RNAseq data was generated from PNETs surgically resected at our institution (9 Female; 12 Male patients). RNA was extracted with the RNeasy Mini Kit, stranded sequencing libraries were prepared with TruSeq, and paired end sequencing was done on the HiSeq 2500/4000 systems. Transcript-level quantification was performed with salmon, and DESeq2 was used for differential expression analysis. To account for significant variation due to covariates other than sex, surrogate variables were computed with the SVA package and adjusted for. The goseq package was used for gene set over representation analysis. Matched DNA methylation (DNAm) and RNAseq data was downloaded from GEO (16 F; 16 M). Raw DNAm data was processed with minfi. Differential methylation analysis was done with limma and bumphunter. Analysis was done in R. RESULTS/ANTICIPATED RESULTS: We found that 826 autosomal genes were differentially expressed (DE) by sex in PNETs (at FDR ≤0.1). Gene set over representation analysis performed on the DE genes revealed significant enrichment for several processes, including ‘ascorbate &amp; aldarate metabolism’ and ‘positive regulation of ERK1 &amp; ERK2 cascade’ (all FDR ≤0.1). When we compared DNAm profiles between sexes, we found 8 CpGs which were differentially methylated by sex (at FDR ≤0.1), 7 of which were proximal to genes. Methylation of one of the sex-associated CpGs, overlapping the gene TIMM8B, was found to be negatively correlated with gene expression (rho=-0.41; p-value=0.02). Interestingly, TIMM8B deletion has been previously reported in other non-pancreatic neuroendocrine tumors. There were no differentially methylated regions between sexes. DISCUSSION/SIGNIFICANCE OF FINDINGS: Our findings demonstrate that PNETs exhibit extensive sexual dimorphisms with regards to gene expression profiles but have largely congruent methylomes by sex. These molecular differences may contribute to the variability in clinical course between men and women, and their characterization is vital for the advancement of personalized medicine.

CT texture analysis of liver metastases in PNETs versus NPNETs: Correlation with histopathological findings

PurposeTo compare CT and Texture features of liver metastases in Pancreatic Neuroendocrine Tumors (PNETs) and in Non-Pancreatic Neuroendocrine Tumors (NPNETs) according to tumor grading, overall survival (OS), time to progression (TTP) and Ki67 index. Methods23 patients with PNETs and 25 patients with NPNETs affected by liver metastases were compared. The lesions were G1 and G2 according to WHO classification of tumors. Texture parameters (Mean, Standard Deviation, Entropy, Kurtosis, Skewness, Mean of Positive Pixel) at different spatial scale image filtration (SSF) were evaluated in both arterial and portal phase using a dedicated software for volumetric analysis. All CT images were acquired before the beginning of any medical treatment. ResultsThe following significant results (P < 0.05) were found: in the arterial phase for value of Skewness between PNETs G2 and NPNETs G2; in the portal phase between PNETs versus NPNETs, PNETs G1 versus NPNETs G1, PNETs G2 versus NPNETs G2; value of Mean in portal phase in PNETs vs NPNETs. Regarding PNETs, a P < 0.05 was found in: inverse correlation between Entropy and TTP; direct correlation between Mean and OS; correlating Kurtosis and high risk of death; correlating Skewness and low risk of death. Regarding NPNETs, P < 0.05 was found in: inverse correlation between Entropy and OS; correlating Entropy and high risk of dying. ConclusionsThis study shows that CT texture features are significantly different in PNETs from NPNETs. Additionally, textural features such as Entropy, Kurtosis and Skewness, were found to have significant correlation with higher mortality risk.

CAPTEM in Metastatic Well-Differentiated Intermediate to High Grade Neuroendocrine Tumors: A Single Centre Experience.

Introduction Capecitabine-temozolomide (CAPTEM) has significant activity in patients (pts) with metastatic low grade pancreatic neuroendocrine tumors (NETs). However, there is limited data regarding its activity in pts with metastatic well-differentiated intermediate and high grade pancreatic and nonpancreatic NETs. The objective of this study was to assess the functional imaging response, survival, and tolerability of CAPTEM in this population. Methods A retrospective audit of pts with metastatic well-differentiated intermediate (WHO grade 2) or high grade (WHO grade 3) NETs treated at Peter MacCallum Cancer Centre between March 2013 and March 2017. Pts received capecitabine 750 mg/m2 orally twice daily (bd) from days1 to 14 and temozolomide 100 mg/m2 bd from days 10 to 14 every 28 days. Data regarding functional imaging response, progression-free and overall survival, and toxicities was collected. Results Thirty-two pts received a median of 6 cycles (range: 2-16) of CAPTEM for grade 2 (n=21, 66%) or grade 3 (n=11, 34%), Ki67 <55% (n= 7, 21.9%) or Ki67 ≥55% (n= 4, 12.5 %) NET. Primary site included gastroenteropancreatic (n= 17, 53%), lung (n= 12, 37.5%), and unknown origin (n = 3, 9.4%). Twenty-two percent received CAPTEM as first-line therapy. After a median of 31 months of follow-up, the two-year overall survival (OS) was 42%, with a median OS of 24 months. There was a trend towards improved median progression-free survival (PFS) in pts with low grade 3 (Ki67<55%) versus high grade 3 (Ki67 ≥55%) NETs (15 vs 4 months, p= 0.11). Ten (31.3%) experienced grade 3/4 toxicity, with nausea (15.6%), thrombocytopaenia (12.5%), and fatigue (9.4%) the most common toxicities reported. Conclusion CAPTEM has significant activity in patients with metastatic grades 2 and 3 NETs with manageable toxicity. The PFS benefit observed in the grade 3 subgroup with Ki67<55% warrants further evaluation in a larger randomized trial.

Safety and Efficacy of the S-1/Temozolomide Regimen in Patients with Metastatic Neuroendocrine Tumors

Purpose: Both capecitabine alone and capecitabine in combination with temozolomide have activities against neuroendocrine tumors (NETs). However, the role of S-1 in NETs is still unknown. We performed a study to evaluate the safety and efficacy of the S-1/temozolomide (STEM) regimen in patients with locally advanced or metastatic NETs. Methods: A retrospective review was conducted in 20 patients with locally advanced or metastatic NETs treated with the STEM regimen. Of the patients, 15 (75.00%) had failed 1 or more lines of treatment with somatostatin analogues, sunitinib, everolimus, anlotinib, or other chemotherapy regimens. The patients received S-1 at 40 mg/m² orally twice daily on days 1-14 and temozolomide 200 mg orally once daily on days 10-14 of a 21-day cycle. The patients were followed up for evidence of object response, toxicity, and progression-free survival. Results: Response to treatment was assessed using RECIST 1.1. Eight patients (40.00%) achieved a partial response (PR), and another 8 (40.00%) had stable disease (SD). The clinical benefit rate (PR and SD) was 80.00%. The median progression-free survival was not achieved. Only 1 patient (5.00%) had grade 3 adverse events. Among the patients with NETs of different origins, 4 (40.00%) and 5 (50.00%) with pancreatic NETs attained PR and SD, respectively. Four (40.00%) and 3 patients (30.00%) with nonpancreatic NETs attained PR and SD, respectively. Conclusions: The STEM regimen is exceptionally highly active and well tolerated in patients with locally advanced or metastatic NETs. Even in patients who showed disease progression with previous therapies, it is still highly active. In this 20-patient study, the regimen appeared to be similarly active in pancreatic endocrine tumors and nonpancreatic NETs.

Abstract 3519: TGF-β pathway alteration in pancreatic neuroendocrine tumors: characterization of a novel SMAD3 translocation

Abstract Pancreatic neuroendocrine tumors (PanNETs) are the second most common malignancy of the pancreas, and the only curative option is represented by surgery. PanNETs can be classified as well- or poorly- differentiated, based on histology. Poorly-differentiated neuroendocrine carcinomas (NECs) represent less than 10% of cases, but they are highly malignant and associated with poor prognosis, and, most importantly, the inconsistency in their clinical management is due to the insufficient data on NEC genetic features. In order to widen our knowledge of PanNET genetic alterations, we performed RNASeq analysis (using Illumina NextSeq platform) of a group of 18 PanNETs and 2 NECs. TopHat-Fusion algorithm identified, among others, a fusion involving SMAD3 transcription factor and CCDC149; the alteration of SMAD3 in a poorly differentiated NEC was particularly interesting since SMAD3 is involved in TGF-b signaling, which has an oncogenic role in malignant cells. The SMAD3-CCDC149 fusion was confirmed in the index case by RT-PCR using primers spanning the breakpoint, followed by Sanger sequencing. The fusion was also detected by FISH analysis performed on both FFPE and frozen samples. By both FISH analysis and Sanger sequencing we identified two other poorly-differentiated NEC samples characterized by the presence of the SMAD3-CCDC149 translocation. Immunohistochemical (IHC) staining revealed that the 3 tumors, positive for the SMAD3-CCDC149 fusion, were characterized by nuclear localization of SMAD3. In order to test the hypothesis that the fusion generates an active form of SMAD3 that localizes exclusively within the nucleus, we transfected BON-1 cell line with plasmids containing either SMAD3 full length or SMAD3 truncated form (the latter mimics the fusion product) showing that only the truncated form of SMAD3 had an exclusively nuclear localization. Interestingly, FISH analysis performed on 3 well-differentiated PanNET samples did not detected the presence of the SMAD3-CDC149 translocation and IHC analysis showed cytoplasmic localization of SMAD3. Moreover, IHC analysis performed on a cohort of 40 cases of non-pancreatic neuroendocrine tumors (NETs) revealed that only poor-differentiated tumors showed a significant percentage of samples with nuclear localization of SMAD3. These data support the hypothesis that the translocation is a typical phenomenon of poorly-differentiated tumors and suggests that it could be involved also in non-pancreatic NETs. In this study we identified a previous unknown SMAD3 translocation in poor-differentiated NECs, which generates an active SMAD3 form. Deepening the knowledge of the fusion product will shed light on PanNET genetic alterations, opening the way to new therapeutic strategies. Citation Format: Emanuela Brunetto, Greta Grassini, Valeria De Pascali, Anna Talarico, Francesca Invernizzi, Michaela Bowden, Massimo Loda, Luca Albarello, Massimo Falconi, Lorenza Pecciarini, Maria G. Cangi, Claudio Doglioni. TGF-β pathway alteration in pancreatic neuroendocrine tumors: characterization of a novel SMAD3 translocation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3519. doi:10.1158/1538-7445.AM2017-3519

The Role of Capecitabine/Temozolomide in Metastatic Neuroendocrine Tumors.

Neuroendocrine tumors (NETs) are commonly treated with multimodality therapy. The combination of capecitabine and temozolomide (CAPTEM) has been suggested as a treatment option for patients with metastatic NETs. We present our experience with CAPTEM. Data on NET patients who were placed on CAPTEM and received at least one cycle were obtained from a Velos eResearch database. Response rate was calculated by RECIST 1.1. Overall survival and progression-free survival (PFS) were calculated by the Kaplan-Meier survival method. A total of 29 patients (17 male and 12 female) were included. Median age at CAPTEM initiation was 58 years (range: 26-77). Primary tumors included 9 small bowel (31%), 15 pancreas (52%), 3 lung (10%), and 2 rectum (7%). Median number of CAPTEM cycles was 8 (range: 1-55). Partial response occurred in 5 patients (5 of 29, 17%); 14 patients (14 of 29, 48%) had stable disease, and 10 patients (10 of 29, 34%) had progressive disease. A total of 3 (20%) and 5 (33%) pancreatic NETs experienced partial response and stable disease, respectively. A total of 2 (14%) and 9 (64%) nonpancreatic NETs experienced partial response and stable disease, respectively. Partial response was noted in 1 patient (13%) and stable disease in 5 patients (63%) with Ki-67 values of less than 2%. In patients with Ki-67 values of 2%-20%, partial response was noted in 3 (19%) and stable disease in 8 (50%). Partial response and stable disease were noted in 1 patient each (20%) with Ki-67 values greater than 20%. Median PFS was 12 months. Adverse reactions caused dose reductions in 24% of patients. Although adverse reactions were experienced, most patients tolerated this regimen. CAPTEM should be considered as a reasonable treatment option for metastatic NET patients. The role of chemotherapy in neuroendocrine tumors has evolved in recent years. The results of this study suggest that the combination of capecitabine and temozolomide provides an adequate treatment option and may prolong survival in patients with a wide variety of metastatic neuroendocrine tumors. Although prospective data are needed, this research adds to the abundance of retrospective experience with this combination that appears to show that capecitabine and temozolomide could potentially be an option for patients with advanced neuroendocrine tumors who have progressed on standard treatment.

Sequential treatment in disseminated well- and intermediate-differentiated pancreatic neuroendocrine tumors: Common sense or low rationale?

Fortunately, the landscape of the systemic treatment for grade 1 and 2 pancreatic neuroendocrine tumors has changed in the last decade with at least four different alternatives approved in the field. Chemotherapy, somatostatin analogues, sunitinib and everolimus remind valid options according to the most referenced international guidelines. However, and although this is something done in the routine practice, there is a lack of evidence for the use of any of these strategies after failure to the others. Moreover, further sequential alternatives in third or fourth line have never been tested prospectively. The need for a better understanding of the rationale to sequence different systemic options is even greater in non-pancreatic neuroendocrine tumors since available therapies are scarce. Sequential strategies in other solid tumors have led to a clear improvement in overall survival. This is also believed to occur in neuroendocrine tumors but no clear data on it has been delivered yet. We postulate that the different mode of action of the systemic options available for the treatment of neuroendocrine tumors may avoid the complete resistance of one option after the other and that sequential use of these agents will be translated into a longer overall survival of patients. Prospective and randomized trials that seek for the activity of drugs after failure to another systemic alternatives are highly needed in this field of neuroendocrine tumors.

Exploring phosphatase and tensin homolog (PTEN) loss via immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) as a potential predictive marker for response to everolimus in patients (pts) with neuroendocrine tumors (NET).

333 Background: Identification of pts with exquisite sensitivity and/or durable responses to targeted therapies may lead to improved patient selection and allow for more rational treatment designs. Exceptional responders to everolimus in NET including pancreatic (PNET) were observed in our cohort of pts. PTEN is a key negative regulator of the phosphatidylinositol 3-kinase(PI3K)/Akt and mammalian target of rapamycin (mTOR) pathway. Loss of PTEN tumor suppressor gene function, usually due to deletion, leads to PI3K/Akt/mTOR pathway activation. Inthis study, we explored the role of PTEN as a potential predictive marker of everolimus in pts with NET including PNET. Methods: Between 2010 and 2014, pts with well-differentiated unresectable and metastatic gastrointestinal NET treated at our institution with everolimus were identified. 17 patients had pathology specimens available for testing. PTEN loss detection by FISH was carried out using a commercially available probe for cytoband 10q23, and by IHC using a commercially available antibody. Patients’ response to everolimus was evaluated through August 2014. The primary outcome was PFS and PTEN status was correlated with PFS for any potential association. Results: The median age was 59 years (range 45-78); 7 were male; 8 had PNET (2 gastrinomas, 1 insulinoma and 5 non-functional); 7 had small bowel NET and 2 unknown primary. All pts received everolimus starting at 10mg daily and octreotide LAR. Of the pts with PNETs, 3 had PTEN loss by FISH. Of those, one did not tolerate everolimus. The PFS for the other two pts was 8 and 24 months respectively. Among the 4 pts with intact PTEN; PFS was 14, 26, 3 and 12 months. 1 patient had insufficient tumor for testing. PTEN FISH is ongoing in the 9 non-pancreatic NET pts. PTEN expression by IHC is also ongoing and will be reported at the meeting. Conclusions: Testing for PTEN loss by FISH is feasible. Due to the small sample size, the role of PTEN loss could not be defined as a predictive marker in PNET. Testing on additional cases is ongoing and will be presented at the meeting.

78IN - Treatment Landscape and Ongoing Clinical Trials in Neuroendocrine Tumors

ABSTRACT Therapy in neuroendocrine tumors (NET) is guided by the presence of hormone-related syndromes, somatostatin receptor status, histology (ki67), aggressiveness and extrahepatic spread. Therapy aims at syndrome and tumor control. Surgery is the only option toward a cure. Loco-regional therapies (e.g. embolisation, radiofrequency ablation) may reduce tumor load and improve clinical syndromes. Somatostatin analogs (SSA) and interferon-alpha are established therapies for carcinoid syndrome (CS). An oral serotonin synthesis inhibitor is evaluated in refractory CS (TELESTAR). Other medical therapies (PPI; diazoxide) are used for syndrome control depending on the tumor type. Antiproliferative therapy options include SSA, novel targeted drugs and systemic chemotherapy. Large placebo-controlled trials provide evidence of the antiproliferative efficacy of SSA (octreotide and lanreotide) in midgut NET and enteropancreatic NET, respectively. Similarly, the novel molecular-targeted therapies, the multiple tyrosine kinase inhibitor (TKI) sunitinib and the mammalian target of rapamycin (mTOR) inhibitor everolimus have been evaluated in placebo-controlled trials, and approved in progressive pancreatic NET. Novel TKIs and combinations of everolimus with SSA or bevacizumab are currently explored in clinical trials to improve response rates or overcome drug resistance. Everolimus and sunitinib (RADIANT-4; Sunland study) are under evaluation in non-pancreatic NET, as well as high dose octreotide vs. Lu-DOTATATE in midgut NET (NETTER-1). Systemic chemotherapy has very limited if any value in slowly growing advanced NET (“carcinoids of different sites”), but is established therapy (streptozotocin/ 5-FU) in pancreatic NET. Future studies will have to establish in which line targeted drugs will be used, especially in pancreatic NET (SEQTOR trial). Molecular markers to preselect patients for specific therapies still need to be identified. Systemic chemotherapy is standard therapy in neuroendocrine carcinoma (NEC G3; first line cisplatin or carboplatin/ etoposide; second-line options include FOLFOX, FOLFIRI or temozolomide +/- capecitabine), however response rates are overall short-lasting (median 4-6 months).

Phase I expansion trial of an oral TORC1/TORC2 inhibitor (CC-223) in nonpancreatic neuroendocrine tumors (NET).

e15004 Background: Clinical activity of everolimus, an allosteric TORC1-selective inhibitor, has been established in pancreatic NET. CC-223 is an ATP-competitive inhibitor of the mTOR kinase, inhibiting both TORC1 and TORC2 complexes. Methods: Following establishment of the MTD (reported at ASCO 2012), subjects with non-pancreatic NET and selected other tumors were enrolled in expansion cohorts of up to 20 evaluable subjects. CC-223 was dosed at 45 mg once daily in 28 day cycles until disease progression. Results: As of 09 January, 2013, 101 solid tumor subjects have been treated. Preliminary results from the NET cohort (n=23) are reported here. Subjects with non-pancreatic tumors of gut origin with progression within 12 months and receiving ongoing treatment with somatostatin analogs (SSA) were eligible. The majority of tumors were of midgut origin with liver metastases; 9 subjects had refractory carcinoid syndrome despite SSA use. The most common (&gt; 20%) related adverse events (all grades) were stomatitis, diarrhea, fatigue, anorexia, nausea and rash. In addition, related serious adverse events included one case of transient dehydration/renal insufficiency (1). CC-223 dose reduction to 30 or 15 mg was required in 57% of subjects, usually during cycle 1 or 2, but thereafter treatment was well tolerated. Inhibition of TORC1 (p4EBP1) and TORC2 (pAKT) biomarkers was confirmed in blood cells. Reduction in glucose uptake (&gt; 25% change in SUV) on PET imaging at day 15 was observed in 54% (7/13) subjects. All evaluable subjects (n=10) reported stable disease (SD) with treatment ongoing at up to 9 cycles (median 6; range 4 – 9). Although not prospectively collected, 6 subjects with refractory carcinoid syndrome reported complete resolution of flushing (5) or improvement in diarrhea (1). Symptom improvement generally occurred within the first week of dosing and persisted despite dose reduction in 5 subjects. Conclusions: Encouraging signals of biomarker and clinical activity were observed in NET including prolonged SD and symptomatic improvement in subjects with refractory carcinoid syndrome. Due to the frequency of early dose reductions, the NET cohort will be explored further at a starting dose of 30 mg QD. Clinical trial information: NCT01177397.

RAMSETE: A single-arm, multicenter, single-stage phase II trial of RAD001 (everolimus) in advanced and metastatic silent neuro-endocrine tumours in Europe.

4122 Background: The mammalian target of rapamycin (mTOR) signaling pathway is involved in the pathogenesis of neuroendocrine tumors (NET). Everolimus (RAD001), an oral mTOR inhibitor, has antitumor activity in patients (pts) with advanced NET. In this open-label, multicenter, phase II study (RAMSETE), the safety and efficacy of everolimus monotherapy was evaluated in pts with advanced nonsyndromic, nonpancreatic NET. Methods: Pts with advanced (unresectable or metastatic), progressive, nonsyndromic, nonpancreatic NET received everolimus (10 mg/day) as monotherapy. The primary endpoint was objective response rate (proportion of pts with best overall complete response [CR] or partial response [PR] per RECIST v1.0) by central radiologic review. A secondary endpoint included progression-free survival (PFS). Results: By database soft lock (December 1, 2011), 73 pts from 16 European clinics received everolimus (median duration of treatment: 193 days). Fifty-five (75%) pts discontinued; reasons included disease progression (n=23), adverse events (AEs [n=23]), withdrawal of consent (n=4), death (n=3), and protocol deviation (n=2). In the per protocol population (N=60), 32 (53%) pts received prior antineoplastic therapy. The best response by central review was stable disease in 55%. By local review, 3 (5%) pts had a PR, with SD in 39 (65%) pts. Median PFS by central review was 185 days (95% CI: 158-255). Median PFS by local investigator review was 285 days (95% CI: 231-not estimable). 69 (95%) pts reported treatment-related AEs of any grade, including rash (n=28; 38%), diarrhea (n=20; 27%), mucosal inflammation (n=18; 25%), and decreased appetite (n=17; 23%). Treatment-related grades 3 and 4 AEs and serious AEs were reported by 27 (37%) and 18 (25%) pts, respectively. Conclusions: In this open-label trial of everolimus in pts with advanced, nonsyndromic, extrapancreatic NET, a high rate of disease stabilization was achieved after prior tumor progression with favorable median PFS. This study further supports efficacy of everolimus in types of NET other than those studied in RADIANT-3 (pancreatic NET) and RADIANT-2 (NET associated with carcinoid syndrome).

Ga-68 DOTA-NOC Uptake in the Pancreas

Gallium-68 (Ga-68) DOTA-1-NaI3-octreotide (DOTA-NOC) positron emission tomography (PET)/computed tomography (CT) is increasingly used for neuroendocrine tumors (NETs), often found primarily in the pancreas. However, physiologic uptake of DOTA-NOC has been described in the uncinate process of the pancreas. We studied DOTA-NOC uptake in this organ. Ninety-six patients underwent 103 DOTA-NOC scans, with pathology-proven pancreatic NET (n = 40) and nonpancreatic NET or biochemical suspicion of NET (n = 63). DOTA-NOC uptake was detected in 35 documented pancreatic tumor sites (SUV: 5.5-165; mean: 25.7 ± 28.8; median: 17.8). Among 63 cases without previous known pathology, uptake was suspicious for tumor in 24 sites (SUV: 4.7-35; mean 16.3 ± 8.0; median: 14.1), and in 38 sites, it was judged as physiological, generally lower relative to adjacent structures (SUV: 2.2-12.6; mean: 6.6 ± 2.2; median: 6.2). In 24 scans with suspected tumor and in 37 of 38 scans with physiological uptake, diagnostic computed tomography or magnetic resonance imaging or endoscopic ultrasonography failed to detect tumor. Pancreatic DOTA-NOC uptake must be interpreted with caution, and further studies are required.

Fluorine-18-l-Dihydroxyphenylalanine (18F-DOPA) Positron Emission Tomography as a Tool to Localize an Insulinoma or β-Cell Hyperplasia in Adult Patients

Fluorine-18-L-dihydroxyphenylalanine (18F-DOPA) positron emission tomography (PET) is a promising method in localizing neuroendocrine tumors. Recently, it has been shown to differentiate focal forms of congenital hyperinsulinism of infancy. The current study was set up to determine the potential of 18F-DOPA PET in identifying the insulin-secreting tumors or beta-cell hyperplasia of the pancreas in adults. We prospectively studied 10 patients with confirmed hyperinsulinemic hypoglycemia and presumed insulin-secreting tumor using 18F-DOPA PET. Anatomical imaging was performed with computed tomography (CT) and magnetic resonance imaging (MRI). All patients were operated on, and histological verification was available in each case. Semiquantitative PET findings in the pancreas using standardized uptake values were compared to standardized uptake values of seven consecutive patients with nonpancreatic neuroendocrine tumors. By visual inspection of 18F-DOPA PET images, it was possible in nine of 10 patients to localize the pancreatic lesion, subsequently confirmed by histological analysis. 18F-DOPA uptake was enhanced in six of seven solid insulinomas and in the malignant insulinoma and its hepatic metastasis. Two patients with beta-cell hyperplasia showed increased focal uptake of 18F-DOPA in the affected areas. As compared to CT or MRI, 18F-DOPA PET was more sensitive in localizing diseased pancreatic tissue. 18F-DOPA PET was useful in most patients with insulinoma and negative CT, MRI, and ultrasound results. In agreement with previous findings in infants, preoperative 18F-DOPA imaging seems to be a method of choice for the detection of beta-cell hyperplasia in adults. It should be considered for the detection of insulinoma or beta-cell hyperplasia in patients with confirmed hyperinsulinemic hypoglycemias when other diagnostic work-up is negative.