scholarly journals Somatostatin Receptors and Analogs in Pheochromocytoma and Paraganglioma: Old Players in a New Precision Medicine World

2021 ◽  
Vol 12 ◽  
Author(s):  
Mayank Patel ◽  
Isabel Tena ◽  
Abhishek Jha ◽  
David Taieb ◽  
Karel Pacak

Neuroendocrine tumors overexpress somatostatin receptors, which serve as important and unique therapeutic targets for well-differentiated advanced disease. This overexpression is a well-established finding in gastroenteropancreatic neuroendocrine tumors which has guided new medical therapies in the administration of somatostatin analogs, both “cold”, particularly octreotide and lanreotide, and “hot” analogs, chelated to radiolabeled isotopes. The binding of these analogs to somatostatin receptors effectively suppresses excess hormone secretion and tumor cell proliferation, leading to stabilization, and in some cases, tumor shrinkage. Radioisotope-labeled somatostatin analogs are utilized for both tumor localization and peptide radionuclide therapy, with 68Ga-DOTATATE and 177Lu-DOTATATE respectively. Benign and malignant pheochromocytomas and paragangliomas also overexpress somatostatin receptors, irrespective of embryological origin. The pattern of somatostatin receptor overexpression is more prominent in succinate dehydrogenase subunit B gene mutation, which is more aggressive than other subgroups of this disease. While the Food and Drug Administration has approved the use of 68Ga-DOTATATE as a radiopharmaceutical for somatostatin receptor imaging, the use of its radiotherapeutic counterpart still needs approval beyond gastroenteropancreatic neuroendocrine tumors. Thus, patients with pheochromocytoma and paraganglioma, especially those with inoperable or metastatic diseases, depend on the clinical trials of somatostatin analogs. The review summarizes the advances in the utilization of somatostatin receptor for diagnostic and therapeutic approaches in the neuroendocrine tumor subset of pheochromocytoma and paraganglioma; we hope to provide a positive perspective in using these receptors as targets for treatment in this rare condition.

2010 ◽  
Vol 17 (1) ◽  
pp. R53-R73 ◽  
Author(s):  
Dik J Kwekkeboom ◽  
Boen L Kam ◽  
Martijn van Essen ◽  
Jaap J M Teunissen ◽  
Casper H J van Eijck ◽  
...  

Somatostatin receptor imaging (SRI) with [111In-DTPA0]octreotide has proven its role in the diagnosis and staging of gastroenteropancreatic neuroendocrine tumors (GEPNETs). Newer radiolabeled somatostatin analogs which can be used in positron emission tomography (PET) imaging, and which have a higher affinity for the somatostatin receptor, especially receptor subtype-2, have been developed. It would be desirable, however, if one radiolabeled analog became the new standard for PET imaging, because the current application of a multitude of analogs implies a fragmented knowledge on the interpretation of the images that are obtained in clinical practice. In our view, the most likely candidates for such a universal PET tracer for SRI are [68Ga-DOTA0,Tyr3]octreotate or [68Ga-DOTA0,Tyr3]octreotide. Treatment with radiolabeled somatostatin analogs is a promising new tool in the management of patients with inoperable or metastasized neuroendocrine tumors. Symptomatic improvement may occur with all 111In-, 90Y-, or 177Lu-labeled somatostatin analogs that have been used for peptide receptor radionuclide therapy (PRRT). The results that were obtained with [90Y-DOTA0,Tyr3]octreotide and [177Lu-DOTA0,Tyr3]octreotate are very encouraging in terms of tumor regression. Also, if kidney protective agents are used, the side effects of this therapy are few and mild, and the median duration of the therapy response for these radiopharmaceuticals is 30 and 40 months respectively. The patients' self-assessed quality of life increases significantly after treatment with [177Lu-DOTA0,Tyr3]octreotate. Lastly, compared to historical controls, there is a benefit in overall survival of several years from the time of diagnosis in patients treated with [177Lu-DOTA0,Tyr3]octreotate. These data compare favorably with the limited number of alternative treatment approaches. If more widespread use of PRRT can be guaranteed, such therapy may well become the therapy of first choice in patients with metastasized or inoperable GEPNETs.


1997 ◽  
Vol 4 (1) ◽  
pp. 1-3 ◽  
Author(s):  
E. Christopher Ellison ◽  
William J. Schirmer ◽  
John O. Olsen ◽  
Rodney V. Pozderac ◽  
George Hinkle ◽  
...  

Background Many imaging methods have been used to detect neuroendocrine tumors of the gastrointestinal system. There is no gold standard for identifying the location of primary tumors and their potential metastases, and most conventional imaging techniques cannot detect tumors less than 1.0 cm in size. Methods The authors have investigated the use of 111In-pentetreotide as an imaging agent for abdominal neuroendocrine tumors. Results The agent is cleared rapidly by the kidneys and is primarily excreted intact with a biologic half-life of six hours. The largest radiation burden is to the spleen and kidneys. A nine-center study conducted in Europe involved 365 patients with gastroenteropancreatic neuroendocrine tumors that were also imaged by other methods. The results of 111In-pentetreotide were in agreement with those obtained by other methods for 79% of tumor locations. An additional 110 tumor localizations were detected that were not seen with conventional methods. The smallest gastrinoma imaged by 111In-pentetreotide was a 4-mm duodenal tumor. Conclusions Scintigraphy with 111In-pentetreotide is effective in visualizing various somatostatin receptors characteristic of neuroendocrine tumors of the gastrointestinal tract. Insulinomas, however, are not well imaged. Concurrent computed tomography scanning is advised to minimize the risk of missing liver metastases.


2018 ◽  
Vol 25 (6) ◽  
pp. R351-R364 ◽  
Author(s):  
Giovanni Vitale ◽  
Alessandra Dicitore ◽  
Concetta Sciammarella ◽  
Sergio Di Molfetta ◽  
Manila Rubino ◽  
...  

Somatostatin analogs have an important role in the medical therapy of neuroendocrine tumors (NETs). Octreotide and lanreotide, both somatostatin analogs binding with high affinity for the somatostatin receptor (SSTR)2, can control symptoms in functional NETs. In addition, these compounds, because of their antiproliferative effects, can stabilize growth of well-differentiated NETs. Pasireotide is a novel multireceptor-targeted somatostatin analog with high affinity for SSTR1, 2, 3, and 5. This review provides an overview of the state of the art of pasireotide in the treatment of NETs, with the aim of addressing clinical relevance and future perspectives for this molecule in the management of NETs.


2020 ◽  
Vol 9 (7) ◽  
pp. 2203 ◽  
Author(s):  
Maria Isabel del Olmo-García ◽  
Maria Angustias Muros ◽  
Martín López-de-la-Torre ◽  
Marc Agudelo ◽  
Pilar Bello ◽  
...  

Neuroendocrine tumors (NETs) frequently overexpress somatostatin receptors (SSTR) on their cell surface. The first-line pharmacological treatment for inoperable metastatic functioning well-differentiated NETs are somatostatin analogs. On second line, Lu-DOTA-TATE (177Lu-DOTA0 Tyr 3 octreotate) has shown stabilization of the disease and an increase in progression free survival, as well as effectiveness in controlling symptoms and increasing quality of life. The management of functional NETs before and during LU-DOTA-TATE treatment is specially challenging, as several complications such as severe carcinoid and catecholamine crisis have been described. The aim of this review is to establish practical guidance for the management and prevention of the most common hormonal crises during radionuclide treatment with Lu-DOTA-TATE: carcinoid syndrome (CS) and catecholamine hypersecretion, as well as to provide a brief commentary on other infrequent metabolic complications. To establish a practical approach, a systematic review was performed. This systematic review was developed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement and conducted using MEDLINE (accessed from PubMed), Google Scholar and ClinicalTrials.gov. Literature searches found 449 citations, and finally nine were considered for this systematic review.


2021 ◽  
Vol 39 (3_suppl) ◽  
pp. 368-368
Author(s):  
Kelley Lauren Coffman ◽  
Lisa Bodei ◽  
Tiffany Le ◽  
Ye Choi ◽  
Joanne F. Chou ◽  
...  

368 Background: 177Lu-DOTATATE is an approved therapy for somatostatin receptor (sstr) positive gastroenteropancreatic neuroendocrine tumors (NETs). There are little data available on response and outcomes for well differentiated (WD) high grade (HG) NETs treated with 177Lu-DOTATATE. Methods: Pts with WD HGNETs treated with 177Lu-DOTATATE at MSK from 2018-2020 were identified. Demographics, response to treatment, and progression-free survival (PFS) were determined. In pts with archival tumor tissue, next-generation sequencing (NGS) was performed through an institutional platform (MSK-IMPACT). Results: 19 pts were identified (mean age 54, 63% female). Site of tumor origin included: pancreas (14/19, 74%), small bowel (2/19, 10.5%), rectal (2/19, 10.5%), lung (1/19, 5%). Average tumor Ki-67 was 34.8 (range 22-56). All tumors were sstr avid on pre-treatment Ga68-DOTATATE PET/CT; none of the patients had sstr negative lesions detected. Median number of prior treatments (systemic and/or liver-directed) was 4 (range 2-7). All pts had progressive disease prior to initiation of 177Lu-DOTATATE. 13 pts (68%) completed all four treatment cycles; treatment was incomplete in 6 pts due to treatment-related toxicities (n = 3) and clinical progression (n = 3). Best response by radiographic report was available in 16 patients (84%):10/16 (63%) with partial response, 1/16 (6%) with stable disease, 5/16 (31%) with disease progression. One pt with stable disease as best response received two additional cycles of 177Lu-DOTATATE at progression. Median PFS (from date of first treatment with 177Lu-DOTATATE until progression/death) was 11.1 months (95% CI 10.6 to NA). Five pts (26%) experienced dose modifying toxicity with 177Lu-DOTATATE. The most common treatment-related toxicities were thrombocytopenia (9 pts, 47%; G3/4 in 1 pt, 5%), anemia (7 pts, 37%; G3/4 in 2 pts, 10.5%), leukopenia (6 pts, 32%; G3/4 in 0 pts), and AST/ALT elevation (4 pts, 21%; G3/4 in 0 pts). NGS results were available in the tumor tissue of 13 pts (68%). The most commonly observed alterations were in MEN1 (6/13, 46%) and DAXX (4/13, 31%). No RB1 alterations were identified. Conclusions: We observed a meaningful disease control rate of 69% during treatment of WD HGNETs with 177Lu-DOTATATE. In this heavily pre-treated population, more than half of pts received all four treatment cycles with treatment-related toxicities largely bone-marrow related, as expected, based on historical data. As would be expected in sstr avid tumors, the vast majority had alterations in chromatin remodeling genes (MEN1, DAXX) consistent with WD NETs, with no RB1 alterations identified.


2019 ◽  
Vol 67 (10) ◽  
pp. 735-743 ◽  
Author(s):  
Satu M. Remes ◽  
Helena L. Leijon ◽  
Tiina J. Vesterinen ◽  
Johanna T. Arola ◽  
Caj H. Haglund

Neuroendocrine neoplasias (NENs) are known to express somatostatin receptors (SSTRs) 1–5, which are G-protein-coupled cell membrane receptors. Somatostatin receptor imaging and therapy utilizes the SSTR expression. Synthetic somatostatin analogs with radioligands are used to detect primary tumors, metastases, and recurrent disease. Receptor analogs are also used for treating NENs. Furthermore, commercially available SSTR antibodies can be used for the immunohistochemical (IHC) detection of SSTRs. We investigated different SSTR antibody clones applying diverse IHC protocol settings to identify reliable clones and feasible protocols for NENs. A tissue microarray including NENs from 12 different primary sites were stained. Only UMB clones were able to localize SSTR on the cell membranes of NENs. SSTR2 (UMB1) emerged as the most common subtype followed by SSTR5 (UMB4) and SSTR1 (UMB7). SSTR3 (UMB5) expression was mainly cytoplasmic. Yet, SSTR4 expression was weak and located primarily in the cytoplasm. Thus, appropriate IHC protocols, including proper positive and negative controls, represent requirements for high-quality NEN diagnostics and for planning personalized therapy.


2019 ◽  
Vol 15 (26) ◽  
pp. 3015-3024
Author(s):  
Natalie Prinzi ◽  
Alessandra Raimondi ◽  
Marco Maccauro ◽  
Massimo Milione ◽  
Enrico Garanzini ◽  
...  

Aim: Data from 69 well-differentiated gastroenteropancreatic neuroendocrine tumors treated with peptide receptor radionucleotide therapy + somatostatin analogs (SSAs) after SSA treatment failure were evaluated. Methods: We identified two groups: S1 – patients who kept the same SSA treatment beyond progression; S2 – patients who switched the SSA with another SSA after progression. Results: Median progression-free survival was 53 and 127 months in S1 and S2, respectively (p = 0.001; hazard ratio: 0.31; 95% CI: 0.15–0.63). Median overall survival was 69 versus 150 months in S1 and S2, respectively (p = 0.004; hazard ratio: 0.32; 95% CI: 0.14–0.71). Conclusion: In patients with advanced well-differentiated gastroenteropancreatic neuroendocrine tumors treated with peptide receptor radionucleotide therapy plus SSA after SSA failure, the ‘switch’ strategy of SSA after progression improve progression-free survival and overall survival.


2021 ◽  
Vol 13 ◽  
pp. 175883592110180
Author(s):  
Satya Das ◽  
Arvind Dasari

Gastroenteropancreatic (GEP) neuroendocrine tumors (NETs) represent the most common subtype of NETs. The incidence of all NETs, and specifically GEP NETs, has risen exponentially over the last three decades. Only within the past several years have these tumors been appropriately classified, allowing for meaningful drug development. Broadly, some of the most exciting drug classes being developed for patients with well-differentiated GEP NETs include newer types of peptide receptor radionuclide therapy (PRRT) or combinations which increase the potency of lutetium-177 (177Lu)-Dotatate, novel multi-target receptor tyrosine kinase inhibitors (RTKIs) and immunotherapy modalities, beyond checkpoint inhibitors, which seek to unleash the immune system against NETs. Specifically looking at newer types of PRRT, somatostatin receptor antagonists and alpha-emitter radionuclides each have demonstrated the ability to elicit greater DNA damage than 177Lu-Dotatate in preclinical models. Early clinical experiences with each of these agents suggest they may be more cytotoxic than 177Lu-Dotatate. Other approaches seeking to build upon the DNA damage created by 177Lu-Dotatate include combinations of PRRT with radiosensitizers such as heat shock protein 90 inhibitors, hedgehog inhibitors, chemotherapy combinations, and triapine. Many of these combinations have just begun to be tested clinically. With regards to novel RTKIs, some of the ones which have demonstrated potent cytoreductive potential include cabozantinib and lenvatinib. Other RTKIs which are further along the clinical development spectrum and have demonstrated benefit in randomized trials include surufatinib and pazopanib. And though single-agent immune checkpoint inhibitors have not demonstrated significant anti-tumor activity in patients with GEP NETs, outside of certain biomarker selected subsets, somatostatin receptor-directed chimeric antigen receptor (CAR) T cells and vaccines such as SurVaxM, which targets survivin, represent two means through which NET-directed immunity may be modulated. The potential of these agents, if clinically realized, will likely improve outcomes for patients with well-differentiated GEP NETs.


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