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Chakraborty, Kushal, Jagannath Mondal, Jeong Man An, Jooho Park e Yong-Kyu Lee. "Advances in Radionuclides and Radiolabelled Peptides for Cancer Therapeutics". Pharmaceutics 15, n.º 3 (17 de março de 2023): 971. http://dx.doi.org/10.3390/pharmaceutics15030971.
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Radiopharmaceutical therapy, which can detect and treat tumours simultaneously, was introduced more than 80 years ago, and it has changed medical strategies with respect to cancer. Many radioactive radionuclides have been developed, and functional, molecularly modified radiolabelled peptides have been used to produce biomolecules and therapeutics that are vastly utilised in the field of radio medicine. Since the 1990s, they have smoothly transitioned into clinical application, and as of today, a wide variety of radiolabelled radionuclide derivatives have been examined and evaluated in various studies. Advanced technologies, such as conjugation of functional peptides or incorporation of radionuclides into chelating ligands, have been developed for advanced radiopharmaceutical cancer therapy. New radiolabelled conjugates for targeted radiotherapy have been designed to deliver radiation directly to cancer cells with improved specificity and minimal damage to the surrounding normal tissue. The development of new theragnostic radionuclides, which can be used for both imaging and therapy purposes, allows for more precise targeting and monitoring of the treatment response. The increased use of peptide receptor radionuclide therapy (PRRT) is also important in the targeting of specific receptors which are overexpressed in cancer cells. In this review, we provide insights into the development of radionuclides and functional radiolabelled peptides, give a brief background, and describe their transition into clinical application.
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Allott, Louis, Suraiya Dubash e Eric O. Aboagye. "[18F]FET-βAG-TOCA: The Design, Evaluation and Clinical Translation of a Fluorinated Octreotide". Cancers 12, n.º 4 (2 de abril de 2020): 865. http://dx.doi.org/10.3390/cancers12040865.
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The success of Lutathera™ ([177Lu]Lu-DOTA-TATE) in the NETTER-1 clinical trial as a peptide receptor radionuclide therapy (PRRT) for somatostatin receptor expressing (SSTR) neuroendocrine tumours (NET) is likely to increase the demand for patient stratification by positron emission tomography (PET). The current gold standard of gallium-68 radiolabelled somatostatin analogues (e.g., [68Ga]Ga-DOTA-TATE) works effectively, but access is constrained by the limited availability and scalability of gallium-68 radiopharmaceutical production. The aim of this review is three-fold: firstly, we discuss the peptide library design, biological evaluation and clinical translation of [18F]fluoroethyltriazole-βAG-TOCA ([18F]FET-βAG-TOCA), our fluorine-18 radiolabelled octreotide; secondly, to exemplify the potential of the 2-[18F]fluoroethylazide prosthetic group and copper-catalysed azide-alkyne cycloaddition (CuAAC) chemistry in accessing good manufacturing practice (GMP) compatible radiopharmaceuticals; thirdly, we aim to illustrate a framework for the translation of similarly radiolabelled peptides, in which in vivo pharmacokinetics drives candidate selection, supported by robust radiochemistry methodology and a route to GMP production. It is hoped that this review will continue to inspire the development and translation of fluorine-18 radiolabelled peptides into clinical studies for the benefit of patients.
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Krenning, E. P., M. de Jong, P. P. M. Kooij, W. A. P. Breeman, W. H. Bakker, W. W. de Herder, C. H. J. van Eijck et al. "Radiolabelled somatostatin analogue(s) for peptide receptor scintigraphy and radionuclide therapy". Annals of Oncology 10 (1999): S23—S30. http://dx.doi.org/10.1093/annonc/10.suppl_2.s23.
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Bodei, Lisa, Chiara M. Grana, Mirco Bartolomei, Silvia M. Baio, Maribel Lopera Sierra e Giovanni Paganelli. "Peptide receptor radionuclide therapy with radiolabelled somatostatin analogues: ten years experience". Biomedicine & Pharmacotherapy 62, n.º 8 (outubro de 2008): 524. http://dx.doi.org/10.1016/j.biopha.2008.07.082.
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Laudicella, Riccardo, Domenico Albano, Salvatore Annunziata, Diletta Calabrò, Giovanni Argiroffi, Elisabetta Abenavoli, Flavia Linguanti et al. "Theragnostic Use of Radiolabelled Dota-Peptides in Meningioma: From Clinical Demand to Future Applications". Cancers 11, n.º 10 (22 de setembro de 2019): 1412. http://dx.doi.org/10.3390/cancers11101412.
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Meningiomas account for approximately 30% of all new diagnoses of intracranial masses. The 2016 World Health Organization’s (WHO) classification currently represents the clinical standard for meningioma’s grading and prognostic stratification. However, watchful waiting is frequently the chosen treatment option, although this means the absence of a certain histological diagnosis. Consequently, MRI (or less frequently CT) brain imaging currently represents the unique available tool to define diagnosis, grading, and treatment planning in many cases. Nonetheless, these neuroimaging modalities show some limitations, particularly in the evaluation of skull base lesions. The emerging evidence supporting the use of radiolabelled somatostatin receptor analogues (such as dota-peptides) to provide molecular imaging of meningiomas might at least partially overcome these limitations. Moreover, their potential therapeutic usage might enrich the current clinical offering for these patients. Starting from the strengths and weaknesses of structural and functional neuroimaging in meningiomas, in the present article we systematically reviewed the published studies regarding the use of radiolabelled dota-peptides in surgery and radiotherapy planning, in the restaging of treated patients, as well as in peptide-receptor radionuclide therapy of meningioma.
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Van Essen, Martijn, Eric P. Krenning, Marion De Jong, Roelf Valkema e Dik J. Kwekkeboom. "Peptide Receptor Radionuclide Therapy with radiolabelled somatostatin analogues in patients with somatostatin receptor positive tumours". Acta Oncologica 46, n.º 6 (janeiro de 2007): 723–34. http://dx.doi.org/10.1080/02841860701441848.
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Reismann, Péter, Zoltán Kender, Gabriella Dabasi, Lídia Sréter, Károly Rácz e Péter Igaz. "Somatostatin receptor endoradiotherapy of neuroendocrine tumors: experience in Hungarian patients". Orvosi Hetilap 152, n.º 10 (março de 2011): 392–97. http://dx.doi.org/10.1556/oh.2011.29057.
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Beside conventional therapies for the treatment of neuroendocrine tumors, a new therapeutical approach, peptide receptor radionuclide therapy has been developed recently. There are two important features which make this therapy feasible: somatostatin receptors are strongly over-expressed in most neuroendocrine tumors resulting in a high tumor-to-background ratio and internalization of the somatostatin-receptor complex in neuroendocrine cells. Due to these features, neuroendocrine tumors can be treated with radiolabelled somatostatin analogues. For peptide receptor radionuclide therapy, somatostatin analogues are conjugated to a chelator that can bind a radionuclide. The most frequently used radionuclides for neuroendocrine tumor treatment are the β-emitter Yttrium-90 (90Y) and the β+γ emitter Lutetium-177 (177Lu). Candidates for somatostatin receptor endoradiotherapy are patients with progressive, metastatic, somatostatin-receptor positive neuroendocrine tumors. Many patients have been successively treated with this approach: according to international results major remission can be achieved in 25% of the cases. Although this therapy is still unavailable in Hungary, Hungarian patients can be treated with somatostatin receptor endoradiotherapy with financial support from the National Health Fund in a co-operation with the University of Basel since 2005. During the past 5 years, 51 Hungarian patients have been treated with this therapy. This review briefly summarizes the theoretical background, indications, effectiveness and side effects of somatostatin receptor endoradiotherapy and the authors present the first data obtained from Hungarian patients. Orv. Hetil., 2011, 152, 392–397.
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Judmann, Benedikt, Diana Braun, Björn Wängler, Ralf Schirrmacher, Gert Fricker e Carmen Wängler. "Current State of Radiolabeled Heterobivalent Peptidic Ligands in Tumor Imaging and Therapy". Pharmaceuticals 13, n.º 8 (30 de julho de 2020): 173. http://dx.doi.org/10.3390/ph13080173.
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Over the past few years, an approach emerged that combines different receptor-specific peptide radioligands able to bind different target structures on tumor cells concomitantly or separately. The reason for the growing interest in this special field of radiopharmaceutical development is rooted in the fact that bispecific peptide heterodimers can exhibit a strongly increased target cell avidity and specificity compared to their corresponding monospecific counterparts by being able to bind to two different target structures that are overexpressed on the cell surface of several malignancies. This increase of avidity is most pronounced in the case of concomitant binding of both peptides to their respective targets but is also observed in cases of heterogeneously expressed receptors within a tumor entity. Furthermore, the application of a radiolabeled heterobivalent agent can solve the ubiquitous problem of limited tumor visualization sensitivity caused by differential receptor expression on different tumor lesions. In this article, the concept of heterobivalent targeting and the general advantages of using radiolabeled bispecific peptidic ligands for tumor imaging or therapy as well as the influence of molecular design and the receptors on the tumor cell surface are explained, and an overview is given of the radiolabeled heterobivalent peptides described thus far.
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Pattison, David A., e Rodney J. Hicks. "Molecular imaging in the investigation of hypoglycaemic syndromes and their management". Endocrine-Related Cancer 24, n.º 6 (junho de 2017): R203—R221. http://dx.doi.org/10.1530/erc-17-0005.
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There has been recent progress in molecular imaging using a variety of cellular targets for the investigation of adult non-diabetic hypoglycaemic syndromes and its integration into patient management. These targets include peptide receptors (somatostatin receptors (SSTRs) and glucagon-like peptide-1 receptor (GLP-1R)) the amine precursor uptake and decarboxylation system utilising the diphydroxyphenylaline (DOPA) analogue 6-[18F]-l-fluoro-l-3,4-dihydroxyphenylalanine (18F-FDOPA), and glycolytic metabolism with 2-[18F]fluoro-2-deoxy-d-glucose (FDG). Accurate preoperative localisation and staging is critical to enable directed surgical excision or enucleation with minimal morbidity and preservation of residual pancreatic function. Benign insulinoma has near ubiquitous dense GLP-1R expression enabling accurate localisation with radiolabelled-exendin-4 compounds (e.g.68Ga-NOTA-exendin-4 PET/CT), whilst the rarer and more difficult to manage metastatic insulinoma typically express SSTR and is preferably imaged with radiolabelled-SSTR analogues such as68Ga-DOTA-octreotate (DOTATATE) PET/CT for staging and assessment of suitability for peptide receptor radionuclide therapy (PRRT). Similar to other metastatic neuroendocrine tumours, FDG PET/CT is used in the setting of higher-grade metastatic insulinoma to provide important prognostic information that can guide treatment and determine suitability for PRRT. Interestingly, these three tracers appear to represent a spectrum of differentiation, which we conceptually describe as the ‘triple-flop’ phenomenon, with GLP-1R > SSTR > FDG in benign insulinoma and the opposite in higher-grade disease. This paper will review the clinical syndromes of adult hypoglycaemia (including a practical overview of the differential diagnoses to be considered), comparison of techniques for insulinoma localisation with emphasis on molecular imaging before discussing its implications for management of metastatic insulinoma.
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Trindade, Victoria, e Henia Balter. "Oxidant and Antioxidant Effects of Gentisic Acid in a 177Lu-Labelled Methionine-Containing Minigastrin Analogue". Current Radiopharmaceuticals 13, n.º 2 (3 de agosto de 2020): 107–19. http://dx.doi.org/10.2174/1874471012666190916112904.
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Background: The radiolabelling of receptor-binding peptides for therapy is a challenge since the peptide itself is exposed (during labelling, storage and transport) to radiation-induced damage, directly or indirectly, in aqueous solution. Hence, the use of radiostabilizers seems to be mandatory, especially in peptide molecules that contain radiation-sensitive amino acids. Objective: The aim of this study was to investigate the effect of two stabilizers, gentisic acid and methionine, to delve into how each of them affects the radiolabelling and stability of the minigastrin analogue [177Lu]Lu-DOTA-His-His-Glu-Ala-Tyr-Gly-Trp-Met-Asp-Phe-NH2 through the analysis of the 22 species distinguished over time by an optimized HPLC system. Methods: The stabilizers, in different combinations, were present from the beginning of the labelling process carried out at 96 °C for 15 min. The stability was studied for up to 7 days. Results: The unexpected selective oxidation of the methionine residue of the radiolabelled peptide, promoted by gentisic acid, led to studying the effect of pH, from 3.5 to 6.0, in the presence of only this stabilizer. A pH-dependent antioxidant behaviour was revealed, showing a decrease in peptide impurities but an increase in the selective oxidation as the pH was increased. Conclusion: The selective oxidation of the methionine residue could be induced by oxidizing species probably produced in the reaction between gentisic acid and free radicals of water, during the protection of the radiolabelled peptide from the attack of these harmful species. Therefore, the addition of methionine becomes necessary to effectively decrease this selective oxidation in the methioninecontaining peptide.
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Grossrubatscher, Erika, Giuseppe Fanciulli, Luca Pes, Franz Sesti, Carlotta Dolci, Federica de Cicco, Annamaria Colao e Antongiulio Faggiano. "Advances in the Management of Medullary Thyroid Carcinoma: Focus on Peptide Receptor Radionuclide Therapy". Journal of Clinical Medicine 9, n.º 11 (29 de outubro de 2020): 3507. http://dx.doi.org/10.3390/jcm9113507.
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Effective treatment options in advanced/progressive/metastatic medullary thyroid carcinoma (MTC) are currently limited. As in other neuroendocrine neoplasms (NENs), peptide receptor radionuclide therapy (PRRT) has been used as a therapeutic option in MTC. To date, however, there are no published reviews dealing with PRRT approaches. We performed an in-depth narrative review on the studies published in this field and collected information on registered clinical trials related to this topic. We identified 19 published studies, collectively involving more than 200 patients with MTC, and four registered clinical trials. Most cases of MTC were treated with PRRT with somatostatin analogues (SSAs) radiolabelled with 90 yttrium (90Y) and 177 lutetium (177Lu). These radiopharmaceuticals show efficacy in the treatment of patients with MTC, with a favourable radiological response (stable disease, partial response or complete response) in more than 60% of cases, coupled with low toxicity. As MTC specifically also expresses cholecystokinin receptors (CCK2Rs), PRRT with this target has also been tried, and some randomised trials are ongoing. Overall, PRRT seems to have an effective role and might be considered in the therapeutic strategy of advanced/progressive/metastatic MTC.
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El-Haddad, Ghassan. "Peptide Receptor Radionuclide Therapy for Gastroenteropancreatic Neuroendocrine Tumors". Digestive Disease Interventions 03, n.º 01 (17 de janeiro de 2019): 071–80. http://dx.doi.org/10.1055/s-0038-1676064.
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AbstractPeptide receptor radionuclide therapy (PRRT), a targeted form of systemic radiotherapy allowing the delivery of radionuclides directly to tumor cells, has been used for more than three decades in the treatment of advanced neuroendocrine tumors (NETs) exhibiting high levels of somatostatin receptors. Recently, 177Lu-DOTATATE, a radiolabeled somatostatin analog, was approved by the US Food and Drug administration for the treatment of somatostatin receptor-positive gastroenteropancreatic neuroendocrine tumors (GEP-NETs) in adults. Early phase I and II studies have shown the benefits of PRRT, but it was the NETTER-1 trial (a large-scale randomized multicenter trial for progressive well-differentiated advanced or metastatic somatostatin receptor-positive midgut carcinoid tumors) that provided high-level evidence of improved overall response rate, and progression-free survival compared with long-acting octreotide. In this article, we will discuss the evolution, clinical applications, and implementation of PRRT, as well as potential future strategies to enhance its clinical efficacy in the treatment of GEP-NETs.
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Merola, Elettra, e Chiara Maria Grana. "Peptide Receptor Radionuclide Therapy (PRRT): Innovations and Improvements". Cancers 15, n.º 11 (30 de maio de 2023): 2975. http://dx.doi.org/10.3390/cancers15112975.
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Neuroendocrine neoplasms (NENs) are tumors originating from neuroendocrine cells distributed throughout the human body. With an increasing incidence over the past few decades, they represent a highly heterogeneous group of neoplasms, mostly expressing somatostatin receptors (SSTRs) on their cell surface. Peptide receptor radionuclide therapy (PRRT) has emerged as a crucial strategy for treating advanced, unresectable neuroendocrine tumors by administering radiolabeled somatostatin analogs intravenously to target SSTRs. This article will focus on the multidisciplinary theranostic approach, treatment effectiveness (such as response rates and symptom relief), patient outcomes, and toxicity profile of PRRT for NEN patients. We will review the most significant studies, such as the phase III NETTER-1 trial, and discuss promising new radiopharmaceuticals, including alpha-emitting radionuclide-labeled somatostatin analogs and SSTR antagonists.
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Bernard, B. F., W. A. P. Breeman, F. Forrer, E. de Blois, J. Hoppin, M. Gotthardt, O. C. Boerman, E. P. Krenning, M. de Jong e E. J. Rolleman. "Molecular imaging of reduced renal uptake of radiolabelled [DOTA0,Tyr3]octreotate by the combination of lysine and Gelofusine in rats". Nuklearmedizin 47, n.º 03 (2008): 110–15. http://dx.doi.org/10.3413/nukmed-0069.
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SummaryAim: In peptide receptor radionuclide therapy (PRRT) using radiolabelled somatostatin analogues, kidney uptake of radiolabelled compound is the major dose-limiting factor. We studied the effects of Gelofusine (20 mg) and lysine (100 mg) and the combination of both after injection of therapeutic doses of radiolabelled [DOTA0,Tyr3]octreotate (60 MBq 111In or 555 MBq 177Lu labelled to 15 μg peptide) in male Lewis rats. Methods: Kidney uptake was measured by single photon emission computed tomography (SPECT) scans with a four-headed multi-pinhole camera (NanoSPECT) at 24 h, 5 and 7 days p. i. and was quantified by volume of interest analysis. For validation the activity concentration in the dissected kidneys was also determined ex vivo using a gamma counter and a dose calibrator. Results: Gelofusine and lysine both reduced kidney uptake of [177Lu-DOTA0,Tyr3]octreotate significantly by about 40% at all time points. The combination of Gelo - fusine and lysine resulted in a 62% inhibition of kidney uptake (p < 0.01 vs. lysine alone). A weak but significant dose-response relationship for Gelofusine, but not for lysine, was found. In a study with [111In-DOTA0,Tyr3]octreotate, conclusions drawn from NanoSPECT data were confirmed by biodistribution data. Conclusions: We conclude that rat kidney uptake of radiolabelled somatostatin analogues can be monitored for a longer period in the same animal using animal SPECT. Gelofusine and lysine had equal potential to reduce kidney uptake of therapeutic doses of [177Lu-DOTA0,Tyr3]octreotate. The combination of these compounds caused a significantly larger reduction than lysine or Gelofusine alone and may therefore offer new possibilities in PRRT. The NanoSPECT data were validated by standard biodistribution experiments.
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Cimini, Andrea, Maria Ricci, Francesca Russo, Martina Egidi, Ferdinando Calabria, Antonio Bagnato, Orazio Schillaci e Agostino Chiaravalloti. "Peptide Receptor Radionuclide Therapy and Primary Brain Tumors: An Overview". Pharmaceuticals 14, n.º 9 (29 de agosto de 2021): 872. http://dx.doi.org/10.3390/ph14090872.
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Primary brain tumors (PBTs) are some of the most difficult types of cancer to treat, and despite advancements in surgery, chemotherapy and radiotherapy, new strategies for the treatment of PBTs are needed, especially for those with poor prognosis such as inoperable/difficult-to-reach lesions or relapsing disease. In regard to the last point, malignant primary brain tumors remain some of the most lethal types of cancer. Nuclear medicine may provide exciting new weapons and significant contributions in the treatment of PBTs. In this review, we performed literature research in order to highlight the possible role of peptide receptor radionuclide therapy (PRRT) in the treatment of PBTs with radiolabeled molecules that bind with high-affinity transmembrane receptors such as somatostatin receptors (SSTRs), neurokinin type-1 receptor and prostate-specific membrane antigen (PSMA). These receptors are overexpressed in some cancer types such as gliomas, meningiomas, pituitary tumors and medulloblastomas. A comprehensive overview of possible applications in this field will be shown, providing knowledge about benefits, feasibility, developments and limitations of PRRT in this type of tumor, also revealing new advantages in the management of the disease.
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Briganti, Vittorio, Vincenzo Cuccurullo, Giuseppe Danilo Di Stasio e Luigi Mansi. "Gamma Emitters in Pancreatic Endocrine Tumors Imaging in the PET Era: Is there a Clinical Space for 99mTc-peptides?" Current Radiopharmaceuticals 12, n.º 2 (16 de julho de 2019): 156–70. http://dx.doi.org/10.2174/1874471012666190301122524.
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Background: Pancreatic Neuroendocrine Tumors (PNETs) are rare neoplasms, sporadic or familial, even being part of a syndrome. Their diagnosis is based on symptoms, hormonal disorders or may be fortuitous. The role of Nuclear Medicine is important, mainly because of the possibility of a theranostic strategy. This approach is allowed by the availability of biochemical agents, which may be labeled with radionuclides suitable for diagnostic or therapeutic purposes, showing almost identical pharmacokinetics. The major role for radiopharmaceuticals is connected with radiolabeled Somatostatin Analogues (SSA), since somatostatin receptors are highly expressed on some of the neoplastic cell types. Discussion: Nowadays, in the category of radiolabeled SSA, although 111In-pentetreotide, firstly commercially proposed, is still used, the best choice for diagnosis is related to the so called DOTAPET radiotracers labeled with 68-Gallium (Ga), such as 68Ga-DOTATATE, 68Ga-DOTANOC, and 68Ga-DOTATOC. More recently, labeling with 64-Copper (Cu) (64Cu-DOTATATE) has also been proposed. In this review, we discuss the clinical interest of a SAA (Tektrotyd©) radiolabeled with 99mTc, a gamma emitter with better characteristics, with respect to 111Indium, radiolabeling Octreoscan ©. By comparing both pharmacokinetics and pharmacodynamics of Octreoscan©, Tektrotyd© and PET DOTA-peptides, on the basis of literature data and of our own experience, we tried to highlight these topics to stimulate further studies, individuating actual clinical indications for all of these radiotracers. Conclusion: In our opinion, Tektrotyd© could already find its applicative dimension in the daily practice of NETs, either pancreatic or not, at least in centers without a PET/CT or a 68Ga generator. Because of wider availability, a lower cost, and a longer decay, compared with respect to peptides labeled with 68Ga, it could be also proposed, in a theranostic context, for a dosimetry evaluation of patients undergoing Peptide Receptor Radionuclide Therapy (PRRT), and for non-oncologic indications of radiolabelled SSA. In this direction, and for a more rigorous cost/effective evaluation, more precisely individuating its clinical role, further studies are needed.
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Huynh, Truc T., Ellen M. van Dam, Sreeja Sreekumar, Cedric Mpoy, Benjamin J. Blyth, Fenella Muntz, Matthew J. Harris e Buck E. Rogers. "Copper-67-Labeled Bombesin Peptide for Targeted Radionuclide Therapy of Prostate Cancer". Pharmaceuticals 15, n.º 6 (8 de junho de 2022): 728. http://dx.doi.org/10.3390/ph15060728.
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The gastrin-releasing peptide receptor (GRPR) is a promising molecular target for imaging and therapy of prostate cancer using bombesin peptides that bind to the receptor with high affinity. Targeted copper theranostics (TCTs) using copper radionuclides, 64Cu for imaging and 67Cu for therapy, offer significant advantages in the development of next-generation theranostics. [64Cu]Cu-SAR-BBN is in clinical development for PET imaging of GRPR-expressing cancers. This study explores the therapeutic efficacy of [67Cu]Cu-SAR-BBN in a pre-clinical mouse model. The peptide was radiolabeled with 67Cu, and specific binding of the radiolabeled peptide towards GRPR-positive PC-3 prostate cancer cells was confirmed with 52.2 ± 1.4% total bound compared to 5.8 ± 0.1% with blocking. A therapy study with [67Cu]Cu-SAR-BBN was conducted in mice bearing PC-3 tumors by injecting 24 MBq doses a total of six times. Tumor growth was inhibited by 93.3% compared to the control group on day 19, and median survival increased from 34.5 days for the control group to greater than 54 days for the treatment group. The ease and stability of the radiochemistry, favorable biodistribution, and the positive tumor inhibition demonstrate the suitability of this copper-based theranostic agent for clinical assessment in the treatment of cancers expressing GRPR.
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Zavvar, Taraneh Sadat, Anton Amadeus Hörmann, Maximilian Klingler, Dominik Summer, Christine Rangger, Laurence Desrues, Hélène Castel, Pierrick Gandolfo e Elisabeth von Guggenberg. "Effects of Side Chain and Peptide Bond Modifications on the Targeting Properties of Stabilized Minigastrin Analogs". Pharmaceuticals 16, n.º 2 (13 de fevereiro de 2023): 278. http://dx.doi.org/10.3390/ph16020278.
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Different attempts have been made in the past two decades to develop radiolabeled peptide conjugates with enhanced pharmacokinetic properties in order to improve the application for tumor imaging and peptide receptor radionuclide therapy (PRRT), which targets the cholecystokinin-2 receptor (CCK2R). In this paper, the influence of different side chain and peptide bond modifications has been explored for the minigastrin analog DOTA-DGlu-Ala-Tyr-Gly-Trp-(N-Me)Nle-Asp-1Nal-NH2 (DOTA-MGS5). Based on this lead structure, five new derivatives were synthesized for radiolabeling with trivalent radiometals. Different chemical and biological properties of the new derivatives were analyzed. Receptor interaction of the peptide derivatives and cell internalization of the radiolabeled peptides were studied in A431-CCK2R cells. The stability of the radiolabeled peptides in vivo was investigated using BALB/c mice. Tumor targeting of all 111In-labeled peptide conjugates, and of a selected compound radiolabeled with gallium-68 and lutetium-177, was evaluated in BALB/c nude mice xenografted with A431-CCK2R and A431-mock cells. All 111In-labeled conjugates, except [111In]In-DOTA-[Phe8]MGS5, showed a high resistance against enzymatic degradation. A high receptor affinity with IC50 values in the low nanomolar range was confirmed for most of the peptide derivatives. The specific cell internalization over time was 35.3–47.3% for all radiopeptides 4 h after incubation. Only [111In]In-DOTA-MGS5[NHCH3] exhibited a lower cell internalization of 6.6 ± 2.8%. An overall improved resistance against enzymatic degradation was confirmed in vivo. Of the radiopeptides studied, [111In]In-DOTA-[(N-Me)1Nal8]MGS5 showed the most promising targeting properties, with significantly increased accumulation of radioactivity in A431-CCK2R xenografts (48.1 ± 9.2% IA/g) and reduced accumulation of radioactivity in stomach (4.2 ± 0.5% IA/g). However, in comparison with DOTA-MGS5, a higher influence on the targeting properties was observed for the change of radiometal, resulting in a tumor uptake of 15.67 ± 2.21% IA/g for [68Ga]Ga-DOTA-[(N-Me)1Nal8]MGS5 and 35.13 ± 6.32% IA/g for [177Lu]Lu-DOTA-[(N-Me)1Nal8]MGS5.
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Mak, Ingrid Y. F., Aimee R. Hayes, Bernard Khoo e Ashley Grossman. "Peptide Receptor Radionuclide Therapy as a Novel Treatment for Metastatic and Invasive Phaeochromocytoma and Paraganglioma". Neuroendocrinology 109, n.º 4 (2019): 287–98. http://dx.doi.org/10.1159/000499497.
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At present there is no clinical guideline or standardised protocol for the treatment of metastatic or invasive phaeochromocytoma and paraganglioma (collectively known as PPGL) due to the rarity of the disease and the lack of prospective studies or extended national databases. Prognosis is mainly determined by genetic predisposition, tumour burden, rate of disease progression, and location of metastases. For patients with progressive or symptomatic disease that is not amenable to surgery, there are various palliative treatment options available. These include localised therapies including radiotherapy, radiofrequency, or cryoablation, as well as liver-directed therapies for those patients with hepatic metastases (e.g., transarterial chemoembolisation) and systemic therapies including chemotherapy or molecular targeted therapies. There is currently intense research interest in the value of radionuclide therapy for neuroendocrine tumours, including phaeochromocytoma and paraganglioma, with either iodine-131 (131I)-radiolabelled metaiodobenzylguanidine or very recently peptide receptor radionuclide therapy (PRRT), and the most important contemporary clinical studies will be highlighted in this review. The studies to date suggest that PRRT may induce major clinical, biochemical, and radiological changes, with 177Lu-DOTATATE being most efficacious and presenting less toxicity than 90Y-DOTATATE. Newer combination therapies with combined radioisotopes, or combinations with chemotherapeutic agents, also look promising. Given the favourable efficacy, logistic, and safety profiles, we believe that PRRT will probably become the standard treatment for inoperable metastatic PPGL in the near future, but we await data from definitive randomised controlled trials to understand its role.
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Zandee, Wouter T., Richard A. Feelders, Daan A. Smit Duijzentkunst, Johannes Hofland, R. Mick Metselaar, Rogier A. Oldenburg, Anne van Linge et al. "Treatment of inoperable or metastatic paragangliomas and pheochromocytomas with peptide receptor radionuclide therapy using 177Lu-DOTATATE". European Journal of Endocrinology 181, n.º 1 (julho de 2019): 45–53. http://dx.doi.org/10.1530/eje-18-0901.
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Objectives Inoperable or metastatic paragangliomas (PGLs) and malignant pheochromocytomas (PCCs) are rare tumours with limited options for systemic treatment. Aim of this study was to assess the safety and efficacy of the radiolabelled somatostatin analogue (177LutetiumDOTA0-Tyr3)octreotate (177Lu-DOTATATE) for the treatment of PGLs and PCCs. Methods Patients with histologically proven inoperable or malignant PGLs and PCCs treated with 177Lu-DOTATATE at our centre were retrospectively analysed. Patients were treated with up to four cycles of 177Lu-DOTATATE with an intended dose of 7.4 Gb per cycle. Response was assessed with use of RECIST 1.1. Results Thirty patients were included: 17 with parasympathetic, 10 with sympathetic PGLs and 3 with PCCs. Grade 3/4 subacute haematotoxicity occurred in 6 (20%) of patients. A reversible subacute adverse event due to cardiac failure following possible catecholamine release occurred in two patients. Best tumour response was partial response in 7 (23%) and stable disease in 20 (67%), whereas 3 (10%) patients had progressive disease. In 20 patients with baseline disease progression, tumour control was observed in 17 (85%); the median progression-free survival was 91 months in patients with parasympathetic PGLs, 13 months in patients with sympathetic PGLs and 10 months in patients with metastatic PCCs. Conclusion This study suggests that PRRT with 177Lu-DOTATATE is a safe and effective treatment option for patients with inoperable or malignant PGL and PCC.
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Kaltsas, G. A., D. Papadogias, P. Makras e A. B. Grossman. "Treatment of advanced neuroendocrine tumours with radiolabelled somatostatin analogues". Endocrine-Related Cancer 12, n.º 4 (dezembro de 2005): 683–99. http://dx.doi.org/10.1677/erc.1.01116.
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Neuroendocrine tumours (NETs) constitute a heterogeneous group of tumours that frequently express cell membrane-specific peptide receptors, such as somatostatin receptors (SSTRs), and of which gastroenteropancreatic (GEP), carcinoid and pancreatic islet cell tumours exhibit the highest expression of SSTRs. Radiolabelled receptor-binding somatostatin analogues (octreotide and lanreotide) act as vehicles to guide radioactivity to tissues expressing SSTRs, and can thus be used for their diagnosis and treatment. After the localization of NETs bearing SSTRs with 111In-octreotide (OctreoScan), a number of radioisotopes with different physical properties have been used for their treatment. The administration of high doses of the Auger electron and γ-emitter 111In-diethylenetriaminepenta-acetic acid (DTPA)0,octreotide in patients with metastatic tumours has been associated with considerable symptomatic improvement but relatively few and short-lived objective tumour responses. The use of another radiolabelled somatostatin analogue coupled with 90Y, a pure β-emitter, 90Y-1,4,7,10-tetraazacyclododecane-N,N′,N″,N‴-tetraacetic acid (DOTA)0,Tyr3,octreotide (90Y-DOTATOC, OctreoTher), was associated with 10–30% objective tumour response rates, and appears to be particularly effective in larger tumours. 111In- and 90Y-DOTA-lanreotide has also been used for the treatment of NETs although its therapeutic efficacy is probably inferior to that of octreotide-based radiopharmaceuticals. More recently, treatment with 177Lu-DOTA0,Tyr3octreotate (177Lu-DOTATATE), which has a higher affinity for the SSTR subtype 2, resulted in approximately 30% complete or partial tumour responses; this radiopharmaceutical is particularly effective in smaller tumours. Furthermore, treatment using both 90Y-DOTATOC and 177Lu-DOTA0,Tyr3octreotate seems promising, as the combination of these radiopharmaceuticals could be effective in tumours bearing both small and large lesions. Tumour regression is positively correlated with a high level of uptake on 111In-octreotide scintigraphy, limited tumour mass and good performance status. In general, better responses have been obtained in GEP tumours than other NETs. The side effects of this form of therapy are relatively few and mild, particularly when kidney-protective agents are used. Treatment with radiolabelled somatostatin analogues presents a promising tool for the management of patients with inoperable or disseminated NETs, and particularly GEP tumours.
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Mather, S. J., A. J. McKenzie, J. K. Sosabowski, T. M. Morris, D. Ellison e S. A. Watson. "Selection of Radiolabeled Gastrin Analogs for Peptide Receptor-Targeted Radionuclide Therapy". Journal of Nuclear Medicine 48, n.º 4 (1 de abril de 2007): 615–22. http://dx.doi.org/10.2967/jnumed.106.037085.
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Hicks, Rodney J., Dik J. Kwekkeboom, Eric Krenning, Lisa Bodei, Simona Grozinsky-Glasberg, Rudolf Arnold, Ivan Borbath et al. "ENETS Consensus Guidelines for the Standards of Care in Neuroendocrine Neoplasms: Peptide Receptor Radionuclide Therapy with Radiolabelled Somatostatin Analogues". Neuroendocrinology 105, n.º 3 (2017): 295–309. http://dx.doi.org/10.1159/000475526.
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Haider, Mintallah, Satya Das, Taymeyah Al-Toubah, Eleonora Pelle, Ghassan El-Haddad e Jonathan Strosberg. "Somatostatin receptor radionuclide therapy in neuroendocrine tumors". Endocrine-Related Cancer 28, n.º 3 (março de 2021): R81—R93. http://dx.doi.org/10.1530/erc-20-0360.
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Peptide receptor radionuclide therapy (PRRT) using 177Lu-DOTATATE has been approved for the treatment of gastroenteropancreatic NETs. An understanding of benefits and risks is important for the appropriate implementation of this therapy. This review summarizes study data supporting the use of radiolabeled somatostatin analogs for the treatment of advanced NETs and highlights risks, including potential toxicities in specific populations. Key ongoing clinical trials, including randomized studies, are designed to better define the position of PRRT within the broader therapeutic landscape. Preclinical and early-phase human studies are focused on the development of novel somatostatin-receptor agonists and antagonists, new radionuclides, and radiosensitizing combination therapies.
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Frilling, Andreja, Ashley Clift, Adil Al-Nahhas, Richard P. Baum e Daniel Kaemmerer. "Surgery and peptide receptor radionuclide therapy: An effective multimodal approach for metastatic neuroendocrine tumors." Journal of Clinical Oncology 37, n.º 15_suppl (20 de maio de 2019): 4113. http://dx.doi.org/10.1200/jco.2019.37.15_suppl.4113.
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4113 Background: Neuroendocrine neoplasia (NEN) of the pancreas (PanNEN) or small bowel (SBNEN) frequently present with metastases at initial diagnosis, undermining the efficacy of surgical treatment. Peptide receptor radionuclide therapy (PRRT) with radiolabelled somatostatin analogues, 90Y-DOTATOC and 177Lu-DOTATATE, has been shown to achieve prolonged progression-free survival (PFS) and overall survival (OS) in a substantial number of non-surgical patients with advanced NEN. Our aim was to prospectively determine the efficacy of a combination of radical loco-regional surgery and 177Lu PRRT in patients with metastasised NEN. Methods: A set of inclusion criteria was defined (e.g. PanNEN or SBNEN, G1/G2 NEN, initial tumour diagnosis, treatment naïve patient, stage IV NEN, positivity on 68Ga DOTATATE or DOTATOC PET/CT, eligibility for surgery and PRRT). Patients underwent PRRT within 3 months following surgery. Follow-up included biochemistry and imaging. Outcome measures included 1-, 3-, and 5-year OS and PFS from initial diagnosis. Results: Forty-one patients met eligibility criteria and were included. There were 26 males (63.4%) and median age at surgery was 58.8 years (range 32.1-78.3). All patients with SBNEN underwent right hemicolectomy, terminal ileal resection and mesenteric lympadenectomy. In PanNEN patients either Whipple procedure or distal pancreatectomy and peripancreatic lymphadenectomy were performed. The median number of PRRT cycles was 4 (range 2-6). Post-treatment mortality was 0%. Surgical morbidity was 12% (all grade 1 according Clavien-Dindo) and transient grade 1 toxicity occurred post PRRT in 40%. There was no grade 3 toxicity. Median follow-up was 5.48 years (range 0.53 – 11.98). Median PFS and OS were 3.33 years and 9.07 years, respectively. Progression-free survival (with 95% CI) was at 1-, 3-, and 5-years 80% (68.7-92.6), 60.9% (45.9-75.9) and 43.3% (27.4-59.3), respectively. Overall survival (with 95% CI) at 1-, 3-, and 5-years was 97.6% (93-100), 97.6% (93-100), and 95% (87-100), respectively. Conclusions: Radical loco-regional surgery for primary tumours combined with PRRT provides a novel, highly efficacious approach in metastasised NEN.
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Eychenne, Romain, Christelle Bouvry, Mickael Bourgeois, Pascal Loyer, Eric Benoist e Nicolas Lepareur. "Overview of Radiolabeled Somatostatin Analogs for Cancer Imaging and Therapy". Molecules 25, n.º 17 (2 de setembro de 2020): 4012. http://dx.doi.org/10.3390/molecules25174012.
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Identified in 1973, somatostatin (SST) is a cyclic hormone peptide with a short biological half-life. Somatostatin receptors (SSTRs) are widely expressed in the whole body, with five subtypes described. The interaction between SST and its receptors leads to the internalization of the ligand–receptor complex and triggers different cellular signaling pathways. Interestingly, the expression of SSTRs is significantly enhanced in many solid tumors, especially gastro-entero-pancreatic neuroendocrine tumors (GEP-NET). Thus, somatostatin analogs (SSAs) have been developed to improve the stability of the endogenous ligand and so extend its half-life. Radiolabeled analogs have been developed with several radioelements such as indium-111, technetium-99 m, and recently gallium-68, fluorine-18, and copper-64, to visualize the distribution of receptor overexpression in tumors. Internal metabolic radiotherapy is also used as a therapeutic strategy (e.g., using yttrium-90, lutetium-177, and actinium-225). With some radiopharmaceuticals now used in clinical practice, somatostatin analogs developed for imaging and therapy are an example of the concept of personalized medicine with a theranostic approach. Here, we review the development of these analogs, from the well-established and authorized ones to the most recently developed radiotracers, which have better pharmacokinetic properties and demonstrate increased efficacy and safety, as well as the search for new clinical indications.
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Cheng, Mei-Fang, Chih-Chieh Yen, Jeng-Shiun Du, Yu-Li Chiu, Ming-Huang Chen, Hui-Jen Tsai, I.-Chen Wu, Hueng-Yuan Shen, Ruoh-Fang Yen e Li-Tzong Chen. "Meeting Notes of the Taiwan Neuroendocrine Tumor Society & Taiwan Society of Nuclear Medicine Joint Conference - Peptide Receptor Radionuclide Therapy Targeting for Gastroenteropancreatic Neuroendocrine Tumors: Basic Principles and State-of-the-art Clinical Practice". Journal of Cancer Research and Practice 11, n.º 2 (abril de 2024): 57–61. http://dx.doi.org/10.4103/ejcrp.ejcrp-d-23-00052.
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Abstract Objective: The current study aimed to investigate the basic principles and clinical applications, including the selection of proper candidates, follow-up strategies, and radiation protection issues relating to peptide receptor radionuclide therapy (PRRT). Data Sources and Study Selection: We searched various scientific databases using specific keywords. Results: Due to the overexpression of somatostatin receptors in neuroendocrine tumors (NETs), PRRT is currently considered an important therapeutic modality for the management of NETs. Conclusion: PRRT incorporates the systemic administration of a tumor-targeting radiolabeled peptide to patients with tumors, allowing for more precise delivery of radiation doses to tumor sites while sparing normal tissues.
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Mandair, Dalvinder, George Demetriou, Leonidas-Nikolaos Diamantopoulos, Haran Devakumar, Rickin Popat, Faidon Laskaratos, Martyn E. Caplin e Christos Toumpanakis. "Predictors of outcome in patients treated with peptide radio-labelled receptor target therapy (PRRT)." Journal of Clinical Oncology 35, n.º 15_suppl (20 de maio de 2017): 4090. http://dx.doi.org/10.1200/jco.2017.35.15_suppl.4090.
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4090 Background: The efficacy of peptide-radiolabelled receptor targeted therapy (PRRT) in patients with well differentiated neuroendocrine tumours has been demonstrated in Phase II and Phase III studies. The recently completed phase IV NETTER-01 demonstrated disease stabilisation or partial response in approximately 80% of patients. However, more studies are needed to identify predictors of PRRT response. We sought to investigate the clinic-pathological characteristics in patients that had radiological progression or death within 12 months of completion of treatment with PRRT. Methods: We performed a retrospective analysis of all patients who had PRRT from 2011-2016. Patient with at least one year of follow-up data from the last treatment dose were included. Patients with evidence of radiological progression within one year of finishing treatment (Group 1) were compared to a similar group with disease stabilisation/response (Group 2)that were matched for age, grade, primary and distribution of metastases. The indication for PRRT was defined as either small volume progression ( < 20%) or progression by RECIST. Results: 307 patients underwent PRRT with Lu-177 or Y-90 DOTATATE during this period. 66 patients in Group 1 were compared to 64 patients in Group 2. There was a significant difference in median overall survival, Group 1 = 21 months compared to Group 2 = 35 months, (p < 0.002). A significantly higher proportion of patients in group 1 had more than 50% liver volume (p < 0.0001). Mean CgA was significantly higher in Group 1, 1250 pg/ml vs 608 pg/ml in Group 2 ( p < 0.03). 18 patients in Group 2 had small volume progression prior to treatment commencement compared to 6 in Group 1 (p < 0.003). Conclusions: Radiological progression within 12 months of completion of PRRT is associated with a worse outcome in terms of OS. Patients with greater liver involvement and highest CgA levels are more likely to progress within 12 months of treatment completion. Earlier treatment with PRRT in patients with radiological progression not meeting RECIST criteria may need to be conisdered. There may be a greater survival benefit if PRRT is given prior to the development of large volume disease.
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Teunissen, Jaap J. M., Dik J. Kwekkeboom, R. Valkema e Eric P. Krenning. "Nuclear medicine techniques for the imaging and treatment of neuroendocrine tumours". Endocrine-Related Cancer 18, S1 (outubro de 2011): S27—S51. http://dx.doi.org/10.1530/erc-10-0282.
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Nuclear medicine plays a pivotal role in the imaging and treatment of neuroendocrine tumours (NETs). Somatostatin receptor scintigraphy (SRS) with [111In-DTPA0]octreotide has proven its role in the diagnosis and staging of gastroenteropancreatic NETs (GEP-NETs). New techniques in somatostatin receptor imaging include the use of different radiolabelled somatostatin analogues with higher affinity and different affinity profiles to the somatostatin receptor subtypes. Most of these analogues can also be labelled with positron-emitting radionuclides that are being used in positron emission tomography imaging. The latter imaging modality, especially in the combination with computed tomography, is of interest because of encouraging results in terms of improved imaging quality and detection capabilities. Considerable advances have been made in the imaging of NETs, but to find the ideal imaging method with increased sensitivity and better topographic localisation of the primary and metastatic disease remains the ultimate goal of research. This review provides an overview of the currently used imaging modalities and ongoing developments in the imaging of NETs, with the emphasis on nuclear medicine and puts them in perspective of clinical practice. The advantage of SRS over other imaging modalities in GEP-NETs is that it can be used to select patients with sufficient uptake for treatment with radiolabelled somatostatin analogues. Peptide receptor radionuclide therapy (PRRT) is a promising new tool in the management of patients with inoperable or metastasised NETs as it can induce symptomatic improvement with all Indium-111, Yttrium-90 or Lutetium-177-labelled somatostatin analogues. The results that were obtained with [90Y-DOTA0,Tyr3]octreotide and [177Lu-DOTA0,Tyr3]octreotate are even more encouraging in terms of objective tumour responses with tumour regression and documented prolonged time to progression. In the largest group of patients receiving PRRT, treated with [177Lu-DOTA0,Tyr3]octreotate, a survival benefit of several years compared with historical controls has been reported.
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Gibbens-Bandala, Brenda, Enrique Morales-Avila, Guillermina Ferro-Flores, Clara Santos-Cuevas, Myrna Luna-Gutiérrez, Gerardo Ramírez-Nava e Blanca Ocampo-García. "Synthesis and Evaluation of 177Lu-DOTA-DN(PTX)-BN for Selective and Concomitant Radio and Drug—Therapeutic Effect on Breast Cancer Cells". Polymers 11, n.º 10 (27 de setembro de 2019): 1572. http://dx.doi.org/10.3390/polym11101572.
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The peptide-receptor radionuclide therapy (PRRT) is a successful approach for selectively delivering radiation within tumor sites through specific recognition of radiolabeled peptides by overexpressed receptors on cancer cell surfaces. The efficacy of PRRT could be improved by using polymeric radio- and drug- therapy nanoparticles for a concomitant therapeutic effect on malignant cells. This research aimed to prepare and evaluate, a novel drug and radiation delivery nanosystem based on the 177Lu-labeled polyamidoamine (PAMAM) dendrimer (DN) loaded with paclitaxel (PTX) and functionalized on the surface with the Lys1Lys3(DOTA)-bombesin (BN) peptide for specific targeting to gastrin-releasing peptide receptors (GRPr) overexpressed on breast cancer cells. DN was first conjugated covalently to BN and DOTA (chemical moiety for lutetium-177 complexing) and subsequently loaded with PTX. The characterization by microscopic and spectroscopic techniques, in-vitro drug delivery tests as well as in in-vitro and in-vivo cellular uptake of 177Lu-DOTA-DN(PTX)-BN by T47D breast cancer cells (GRPr-positive), indicated the formation of an improved delivery nanosystem with target-specific recognition by GRPr. Results of the 177Lu-DOTA-DN(PTX)-BN effect on T47D cell viability (1.3%, compared with 10.9% of 177Lu-DOTA-DN-BN and 14.0% of DOTA-DN-(PTX)-BN) demonstrated the concomitant radiotherapeutic and chemotherapeutic properties of the polymeric nanosystem as a potential agent for the treatment of GRPr-positive tumors.
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Bison, Sander M., Mark W. Konijnenberg, Marleen Melis, Stefan E. Pool, Monique R. Bernsen, Jaap J. M. Teunissen, Dik J. Kwekkeboom e Marion de Jong. "Peptide receptor radionuclide therapy using radiolabeled somatostatin analogs: focus on future developments". Clinical and Translational Imaging 2, n.º 1 (fevereiro de 2014): 55–66. http://dx.doi.org/10.1007/s40336-014-0054-2.
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Adams, Christopher Peter, e Wasif M. Saif. "Targeted radiopeptide therapy Re188-P2045 to treat neuroendocrine lung cancer." Journal of Clinical Oncology 35, n.º 15_suppl (20 de maio de 2017): e20016-e20016. http://dx.doi.org/10.1200/jco.2017.35.15_suppl.e20016.
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e20016 Background: : Despite the recent success of checkpoint inhibitors, there continues to be a significant medical need for lung cancer therapies that can be directed to the patients most likely to respond. Somatostatin receptor subtype 2 (SSTR2) is the most widely up-regulated subtype in both small and non-small cell lung cancers and is also expressed in tumoral (but not mature) blood vessels. Peptide targeted radiotherapy has advantages over traditional targeted therapies in that targeted tumor cells as well as surrounding cancer cells and supporting stroma are selectively killed. This study was conducted to determine the ability of Rhenium Re 188 P2045, a radiolabeled somatostatin analog specific for SSTR2 to both image (to select the most appropriate patients) and treat lung cancer patients who over-express somatostatin receptors. Methods: In an open label, single arm study, refractory lung cancer patients to standard of care therapy were identified by image analysis using Rhenium Re 188 P2045, a radiolabeled somatostatin analog. 25 Patients received the imaging dose of 10uCi of Re188 and 265ng of peptide by intravenous injection. Three patients were selected based on high SSTR expression levels to receive 30uCi of Re188 P2045 as a therapeutic dose 14 days after imaging. Patients were followed for 8 weeks post treatment. Results: The imaging study revealed a high density of expression of the somatostatin receptor in the lungs of patients. Patients in the imaging and therapeutic treatment groups reported no adverse advents or signs of toxicity. The image analysis using Re188 P2045 was compared to CT images and demonstrated accurate detection of lung tumor lesions. The images obtained using Re188 P2045 were of sufficiently high quality to enable identification of receptor expression at the tumor site as shown in Figures 1&2. Conclusions: Rhenium Re 188 P2045, a radiolabeled somatostatin analog, may be used to both identify and treat lung cancer tumors. The ability to image and dose patients with the same targeted molecule enables a personalized medicine approach and this highly targeted patient therapy may significantly improve treatment of tumors that over express somatostatin receptor.
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Shih, Ming-Chi, Sergio Daniel Simon, Zhiming Jin, Yuan Gui, Bohua Xu, Zhihong Xu, Paulo Henrique Rosado-de-Castro et al. "Efficient Synthesis of Glutamate Peptide-Estradiol Conjugate for Imaging Estrogen Receptor-Positive Diseases". BioMed Research International 2018 (25 de setembro de 2018): 1–14. http://dx.doi.org/10.1155/2018/5208964.
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Molecular imaging of estrogen receptor-positive (ER+) pathway-activated system serves the basis of ER+ disease management such as cancers and endometriosis. ER+ patients have better response to endocrine therapy and survive twice as long as negative ER patients. However, tumor resistance resulting from clinical used aromatase inhibitors and antiestrogens is unpredictable. Radiolabeled ER+ ligand could quantify ER+ tissue uptake which helps to stage and restage of the cancer as well as endometriosis. The differential diagnosis of ER+ lesions by using a labeled ligand helps to select the patients for optimal response to endocrine therapy and to discontinue the treatment when resistance occurs. In addition, radiolabeled ER+ ligand serves as basis for image-guided response follow-up. Glutamate receptors are cell surface receptors which are overexpressed in inflammation and infection. Using glutamate peptide as a drug carrier helps to target intracellular genes via glutamate receptor-mediated process. Reports have shown that polyglutamate is a drug carrier that could alter drug solubility and enhance estrogen receptor-ligand binding pocket. However, polyglutamate was a blend of mixed polymer with a wide range of molecular weight. Thus, the structural confirmation and purity of the conjugates were not optimized. To overcome this problem, the efficient synthesis of glutamate peptide-estradiol (GAP-EDL) conjugate was achieved with high purity. EDL was conjugated site-specific at the first glutamate of GAP. The average cell uptake of 68Ga-GAP-EDL was 5-fold higher than the previous reported synthesis. The efficient synthesis of GAP-EDL has greatly enhanced sensitivity and specificity in cell uptake studies. In vivo PET imaging studies indicated that 68Ga-GAP-EDL could image ER (+) tumors in MCF-7 tumor-bearing mice. Therefore, GAP-EDL makes it possible to image ER-enriched endometriosis and cancer.
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Hänscheid, Heribert, Philipp E. Hartrampf, Andreas Schirbel, Andreas K. Buck e Constantin Lapa. "Intraindividual comparison of [177Lu]Lu-DOTA-EB-TATE and [177Lu]Lu-DOTA-TOC". European Journal of Nuclear Medicine and Molecular Imaging 48, n.º 8 (15 de janeiro de 2021): 2566–72. http://dx.doi.org/10.1007/s00259-020-05177-z.
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Abstract Purpose The radiolabelled somatostatin analogue [177Lu]Lu-DOTA-EB-TATE binds to albumin via Evans blue, thereby increasing the residence time in the blood and potentially allowing more therapeutic agent to be absorbed into the target tissue during peptide receptor radionuclide therapy. It was tested in selected patients whether the substance is superior to [177Lu]Lu-DOTA-TOC. Methods Activity kinetics in organs and tumours after [177Lu]Lu-DOTA-EB-TATE and [177Lu]Lu-DOTA-TOC were compared intraindividually in five patients with progressive somatostatin receptor-positive disease scheduled for radionuclide therapy. Results In comparison to [177Lu]Lu-DOTA-TOC, tumour doses per administered activity were higher for [177Lu]Lu-DOTA-EB-TATE in 4 of 5 patients (median ratio: 1.7; range: 0.9 to 3.9), kidney doses (median ratio: 3.2; range: 1.6 to 9.8) as well as spleen doses (median ratio: 4.7; range 1.2 to 6.2) in all patients, and liver doses in 3 of 4 evaluable patients (median ratio: 4.0; range: 0.7 to 4.9). The tumour to critical organs absorbed dose ratios were higher after [177Lu]Lu-DOTA-TOC in 4 of 5 patients. Conclusions Prior to a treatment with [177Lu]Lu-DOTA-EB-TATE, it should be assessed individually whether the compound is superior to established substances.
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Nock, Berthold A., Panagiotis Kanellopoulos, Lieke Joosten, Rosalba Mansi e Theodosia Maina. "Peptide Radioligands in Cancer Theranostics: Agonists and Antagonists". Pharmaceuticals 16, n.º 5 (30 de abril de 2023): 674. http://dx.doi.org/10.3390/ph16050674.
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The clinical success of radiolabeled somatostatin analogs in the diagnosis and therapy—“theranostics”—of tumors expressing the somatostatin subtype 2 receptor (SST2R) has paved the way for the development of a broader panel of peptide radioligands targeting different human tumors. This approach relies on the overexpression of other receptor-targets in different cancer types. In recent years, a shift in paradigm from internalizing agonists to antagonists has occurred. Thus, SST2R-antagonist radioligands were first shown to accumulate more efficiently in tumor lesions and clear faster from the background in animal models and patients. The switch to receptor antagonists was soon adopted in the field of radiolabeled bombesin (BBN). Unlike the stable cyclic octapeptides used in the case of somatostatin, BBN-like peptides are linear, fast to biodegradable and elicit adverse effects in the body. Thus, the advent of BBN-like antagonists provided an elegant way to obtain effective and safe radiotheranostics. Likewise, the pursuit of gastrin and exendin antagonist-based radioligands is advancing with exciting new outcomes on the horizon. In the present review, we discuss these developments with a focus on clinical results, commenting on challenges and opportunities for personalized treatment of cancer patients by means of state-of-the-art antagonist-based radiopharmaceuticals.
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Kasi, Pashtoon M., Akash Sharma e Manoj K. Jain. "Expanding the Indication for Novel Theranostic 177Lu-Dotatate Peptide Receptor Radionuclide Therapy: Proof-of-Concept of PRRT in Merkel Cell Cancer". Case Reports in Oncology 12, n.º 1 (21 de janeiro de 2019): 98–103. http://dx.doi.org/10.1159/000496335.
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The field of theranostics is a new nuclear medicine tool being utilized in the treatment of different types of cancers. It couples receptor-specific based imaging predicting and guiding response to receptor-specific based radionuclide therapies. For example, somatostatin-receptor based imaging (Gallium; 68Ga-dotatate scan) is now predicting and guiding the use of treatment with the somatostatin-receptor radiolabeled somatostatin analog (peptide receptor radionuclide therapy PRRT – Lutetium; 177Lu-Dotatate) for neuroendocrine tumors that express the somatostatin receptors. The United States Food and Drug Administration approved the use of 177Lu-Dotatate PRRT for somatostatin-receptor-positive gastroenteropancreatic neuroendocrine tumors only. Here we show proof of concept and results of an outstanding response to this novel therapy in conjunction with immunotherapy in a refractory cancer type where it has not been approved (Merkel Cell Cancer). Our results and data provide proof of principle for considering the use of this novel therapy in a tumor-agnostic approach; similar to approval of immunotherapy for mismatch repair deficient tumors. The response demonstrated has also been unprecedented, likely secondary to use of PRRT with immunotherapy. These observations have profound and broad implications on how to move this novel field of theranostics forward for treatment of many cancer-types.
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Kiesewetter, Barbara, e Markus Raderer. "How I treat neuroendocrine tumours". ESMO Open 5, n.º 4 (agosto de 2020): e000811. http://dx.doi.org/10.1136/esmoopen-2020-000811.
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Neuroendocrine tumours (NETs) constitute a heterogeneous group of neoplasms characterised by variable endocrine activity and somatostatin receptor expression, with the latter allowing the use of targeted therapeutic concepts. Currently accepted treatment strategies for advanced well-differentiated NET include somatostatin analogues octreotide and lanreotide, peptide receptor radionuclide therapy using radiolabelled somatostatin analogues, mammalian target of Rapamycin inhibitor everolimus, tyrosine kinase inhibitor sunitinib, interferon alpha and classical cytostatic, such as streptozotocin-based and temozolomide-based treatment. Indication, use and approval of these treatments differ based on primary tumour origin, grading and symptomatic burden and require an optimised multidisciplinary cooperation of medical oncologists, endocrinologists and nuclear medicine specialists. Interestingly, hot topics in oncology including immunotherapy and use of next-generation-sequencing techniques currently play a minor role for the treatment of NETs. The recent revision of the WHO classification including the recognition of the novel NET G3 category allows for potentially more tailored treatment strategies in the near future. However, this new entity also poses a therapeutic challenge as only limited data are currently available. The present article aims to provide an overview on our personal treatment concepts for advanced NETs with a focus on tumours of gastroenteropancreatic origin.
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Masłowska, Katarzyna, Paweł Krzysztof Halik, Dagmara Tymecka, Aleksandra Misicka e Ewa Gniazdowska. "The Role of VEGF Receptors as Molecular Target in Nuclear Medicine for Cancer Diagnosis and Combination Therapy". Cancers 13, n.º 5 (3 de março de 2021): 1072. http://dx.doi.org/10.3390/cancers13051072.
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One approach to anticancer treatment is targeted anti-angiogenic therapy (AAT) based on prevention of blood vessel formation around the developing cancer cells. It is known that vascular endothelial growth factor (VEGF) and vascular endothelial growth factor receptors (VEGFRs) play a pivotal role in angiogenesis process; hence, application of angiogenesis inhibitors can be an effective approach in anticancer combination therapeutic strategies. Currently, several types of molecules have been utilised in targeted VEGF/VEGFR anticancer therapy, including human VEGF ligands themselves and their derivatives, anti-VEGF or anti-VEGFR monoclonal antibodies, VEGF binding peptides and small molecular inhibitors of VEGFR tyrosine kinases. These molecules labelled with diagnostic or therapeutic radionuclides can become, respectively, diagnostic or therapeutic receptor radiopharmaceuticals. In targeted anti-angiogenic therapy, diagnostic radioagents play a unique role, allowing the determination of the emerging tumour, to monitor the course of treatment, to predict the treatment outcomes and, first of all, to refer patients for AAT. This review provides an overview of design, synthesis and study of radiolabelled VEGF/VEGFR targeting and imaging agents to date. Additionally, we will briefly discuss their physicochemical properties and possible application in combination targeted radionuclide tumour therapy.
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Calistri, Sara, Giuseppe Ottaviano e Alberto Ubaldini. "Radiopharmaceuticals for Pancreatic Cancer: A Review of Current Approaches and Future Directions". Pharmaceuticals 17, n.º 10 (1 de outubro de 2024): 1314. http://dx.doi.org/10.3390/ph17101314.
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The poor prognosis of pancreatic cancer requires novel treatment options. This review examines the evolution of radiopharmaceuticals in the treatment of pancreatic cancer. Established strategies such as peptide receptor radionuclide therapy (PRRT) offer targeted and effective treatment, compared to conventional treatments. However, there are currently no radiopharmaceuticals approved for the treatment of pancreatic cancer in Europe, which requires further research and novel approaches. New radiopharmaceuticals including radiolabeled antibodies, peptides, and nanotechnological approaches are promising in addressing the challenges of pancreatic cancer therapy. These new agents may offer more specific targeting and potentially improve efficacy compared to traditional therapies. Further research is needed to optimize efficacy, address limitations, and explore the overall potential of these new strategies in the treatment of this aggressive and harmful pathology.
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Ilincic, Branislava, Zoran Stosic, Velibor Cabarkapa, Radmila Zeravica e Romana Mijovic. "Accurate assessment of renal function prior and after peptide receptor radionuclide therapy". Archive of Oncology 21, n.º 3-4 (2013): 146–50. http://dx.doi.org/10.2298/aoo1304146i.
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Peptide receptor radiation therapy (PRRT) with radiolabeled octreotide analogs is effective treatment in patients with somatostatin receptor-positive neuroendocrine tumors. The kidneys are critical organ during PRRT because of peptide reabsorption, retention, and prolonged irradiation in the proximal tubules. We presented results of kidney functions tests in four patients before and after PRRT with 90Y-DOTATOC and 177Lu-DOTATATE, with special reference to the pathophysiology of preexisting multiple risk factors for kidney impairment. We conducted several methods routinely used in clinical practice to determine kidney function - serum creatinine, serum cystatin C, creatinine clearance (CrCl) through 24 hours of urine collection and mathematical equations for prediction of glomerular filtration rate (GFR). A very accurate measurement of kidney function (GFR and effective renal plasma flow) was done by radioactive tracers - 99Tc- diethyl triamine pentaacetic acid and 131I ortho-iodohippurate plasma clearance. Beside PRRT nephrotoxicity, patient age, preexisting kidney disease, and chronic comorbidities contribute to the risk of renal impairment. Because clinically relevant differences were assessed between calculated values and the real situation, mathematical calculation of GFR or CrCl did not seem to be appropriate to assess individual renal function precisely enough.
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Singh, Jaswinder, e GINA J. Singh. "Development of hematologic toxicity with sequential treatment of Y90 followed by PRRT in five patients at single institution with metastatic neuroendocrine patients." Journal of Global Oncology 5, suppl (7 de outubro de 2019): 81. http://dx.doi.org/10.1200/jgo.2019.5.suppl.81.
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81 Background: In metastatic neuroendocrine tumors (NET) peptide receptor radionuclide therapy (PRRT) using radiolabeled somatostatin analogues (Lu-177-DOTATATE) and selective intra-arterial radio-therapy (SIRT) with Y-90-microspheres are increasingly used promising treatment options. Rarely patients have been treated with sequential use of both treatment modalities . Severe adverse effects are rare and mainly concern hematologic changes and development of prolonged cytopenias . There is no data about possible cumulative side effects particularly regarding hematologic toxicity in the case of sequential use of both treatments. Methods: 5 Patients with hepatic metastasized NET treated both with SIRT and PRRT during 2010 - 2019 were included. Average time interval between treatment of y90 and PRRT was 2.5 years. All of them were treated with y90 before PRRT. Average treatment with Y90 was 3 doses. Results: In the follow up Platelets (159 to 89), leukocytes (7.5 to 3.7) and hemoglobin (13 to 11.6 ) decreased significantly, LFTs, bilirubin and creatinine did not change significantly. No severe toxicity (Grade 3 or 4) was experienced. 80 % of the patients showed decreasing blood counts after the therapies and was prolonged for average of 9 months. Conclusions: In metastatic neuroendocrine tumors (NET) sequential treatment with peptide receptor radionuclide therapy (PRRT) using radiolabeled somatostatin analogues (Lu-177-DOTATATE) after selective intra-arterial radio-therapy (SIRT) with Y-90-microspheres is possible and well tolerated except for hematological toxicity.
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Ambrosini, Valentina, Lucia Zanoni, Angelina Filice, Giuseppe Lamberti, Giulia Argalia, Emilia Fortunati, Davide Campana, Annibale Versari e Stefano Fanti. "Radiolabeled Somatostatin Analogues for Diagnosis and Treatment of Neuroendocrine Tumors". Cancers 14, n.º 4 (19 de fevereiro de 2022): 1055. http://dx.doi.org/10.3390/cancers14041055.
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Neuroendocrine neoplasms (NENs) are rare and heterogeneous tumors that require multidisciplinary discussion for optimal care. The theranostic approach (DOTA peptides labelled with 68Ga for diagnosis and with 90Y or 177Lu for therapy) plays a crucial role in the management of NENs to assess disease extension and as a criteria for peptide receptor radionuclide therapy (PRRT) eligibility based on somatostatin receptor (SSTR) expression. On the diagnostic side, [68Ga]Ga-DOTA peptides PET/CT (SSTR PET/CT) is the gold standard for imaging well-differentiated SSTR-expressing neuroendocrine tumors (NETs). [18F]FDG PET/CT is useful in higher grade NENs (NET G2 with Ki-67 > 10% and NET G3; NEC) for more accurate disease characterization and prognostication. Promising emerging radiopharmaceuticals include somatostatin analogues labelled with 18F (to overcome the limits imposed by 68Ga), and SSTR antagonists (for both diagnosis and therapy). On the therapeutic side, the evidence gathered over the past two decades indicates that PRRT is to be considered as an effective and safe treatment option for SSTR-expressing NETs, and is currently included in the therapeutic algorithms of the main scientific societies. The positioning of PRRT in the treatment sequence, as well as treatment personalization (e.g., tailored dosimetry, re-treatment, selection criteria, and combination with other alternative treatment options), is warranted in order to improve its efficacy while reducing toxicity. Although very preliminary (being mostly hampered by lack of methodological standardization, especially regarding feature selection/extraction) and often including small patient cohorts, radiomic studies in NETs are also presented. To date, the implementation of radiomics in clinical practice is still unclear. The purpose of this review is to offer an overview of radiolabeled SSTR analogues for theranostic use in NENs.
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Naik, Mitesh, Adil Al-Nahhas e Sairah R. Khan. "Treatment of Neuroendocrine Neoplasms with Radiolabeled Peptides—Where Are We Now". Cancers 14, n.º 3 (1 de fevereiro de 2022): 761. http://dx.doi.org/10.3390/cancers14030761.
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Peptide receptor radionuclide therapy (PRRT) has been one of the most successful and exciting examples of theranostics in nuclear medicine in recent decades and is now firmly embedded in many treatment algorithms for unresectable or metastatic neuroendocrine neoplasms (NENs) worldwide. It is widely considered to be an effective treatment for well- or moderately differentiated neoplasms, which express high levels of somatostatin receptors that can be selectively targeted. This review article outlines the scientific basis of PRRT in treatment of NENs and describes its discovery dating back to the early 1990s. Early treatments utilizing Indium-111, a γ-emitter, showed promise in reduction in tumor size and improvement in biochemistry, but were also met with high radiation doses and myelotoxic and nephrotoxic effects. Subsequently, stable conjugation of DOTA-peptides with β-emitting radionuclides, such as Yttrium-90 and Lutetium-177, served as a breakthrough for PRRT and studies highlighted their potential in eliciting progression-free survival and quality of life benefits. This article will also elaborate on the key trials which paved the way for its approval and will discuss therapeutic considerations, such as patient selection and administration technique, to optimize its use.
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Okarvi, Subhani M., e Ibrahim AlJammaz. "Development of the Tumor-Specific Antigen-Derived Synthetic Peptides as Potential Candidates for Targeting Breast and Other Possible Human Carcinomas". Molecules 24, n.º 17 (29 de agosto de 2019): 3142. http://dx.doi.org/10.3390/molecules24173142.
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The human epidermal growth factor receptor 2 (HER2) represents one of the most studied tumor-associated antigens for cancer immunotherapy. The receptors for HER2 are overexpressed in various human cancers, such as breast and ovarian cancer. The relatively low expression of this antigen on normal tissues makes it a clinically useful molecular target for tumor imaging and targeted therapy. HER2 overexpression is correlated with aggressive tumor behavior and poor clinical outcomes. Thus, HER2 has become an important prognostic and predictive factor, as well as a potential molecular target. Due to the heterogeneity of breast cancer and possible discordance in HER2 status between primary tumors and distant metastases, assessment of HER2 expression by noninvasive imaging is important. Molecular imaging of HER2 expression may provide essential prognostic and predictive information concerning disseminated cancer and aid in the selection of an optimal therapy. Another tumor-specific antigen is MUC1, which is silent on normal tissues, but overexpressed in almost all human epithelial cell cancers, including >90% of human breast, ovarian, pancreatic, colorectal, lung, prostate, and gastric cancers and is a promising tumor antigen with diagnostic as well as the therapeutic potential of cancer. Radiolabeled small peptide ligands are attractive as probes for molecular imaging, as they reach and bind the target receptor efficiently and clear from blood and non-target organs faster than bulky antibodies. In this study, HER2 and MUC1-based peptides were synthesized and preclinically evaluated in an effort to develop peptide-based SPECT radiopharmaceuticals derived from tumor-associated antigens for the detection of breast cancer. Our findings demonstrate that the tumor antigen peptides radiolabeled efficiently with 99mTc and showed high metabolic stability in human plasma in vitro. The data from breast tumor cell binding confirmed the high affinity (in low nanomolar range) towards respective breast cancer cell lines. In healthy mice, 99mTc-labeled peptides displayed favorable pharmacokinetics, with high excretion by the renal system. In tumor xenografts nude mice models, good uptake by the SKBR3, MCF7, and T47D tumors were found, with good tumor-to-blood and tumor to muscle ratios. Additionally, tumor lesions can be seen in γ-camera imaging. Our data suggest that based on its ability to detect HER2- and MUC1-positive breast cancer cells in vivo, 99mTc-HER2 and 99mTc-MUC1-targeted peptides may be promising tumor imaging probes and warrant further investigation.
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Kwekkeboom, Dik J., Boen L. Kam, Martijn van Essen, Jaap J. M. Teunissen, Casper H. J. van Eijck, Roelf Valkema, Marion de Jong, Wouter W. de Herder e Eric P. Krenning. "Somatostatin receptor-based imaging and therapy of gastroenteropancreatic neuroendocrine tumors". Endocrine-Related Cancer 17, n.º 1 (março de 2010): R53—R73. http://dx.doi.org/10.1677/erc-09-0078.
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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.
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Sharma, Rohini, Caroline Ward, Mitesh Naik, Saraih Khan, Tara Barwick, Maria Martinez, Hooshang Izadi e Eric O. Aboagye. "LANTana trial protocol: An open label, single arm, phase Ib study to evaluate the effect of pre-treatment with ASTX727 (a demethylating agent) followed by lutetium Lu 177 dotatate in patients with progressive, metastatic neuroendocrine neoplasias (NENs)." Journal of Clinical Oncology 41, n.º 16_suppl (1 de junho de 2023): TPS4192. http://dx.doi.org/10.1200/jco.2023.41.16_suppl.tps4192.
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TPS4192 Background: Neuroendocrine neoplasias (NENs) are characterised by the presence of somatostatin receptors (SSTR) on cell surface, in particular SSTR2. Somatostatin and its stable analogue (SSA) bind with high affinity to SSTR2. SSA can be radiolabelled, to both stage NENs using positron emission tomography (PET), and to deliver selective radiotherapy; peptide receptor radionuclide therapy (PRRT). PRRT consists of SSA linked to the long acting radionuclide. Radiolabelled SSA binds to SSTR2 and the complex is internalised delivering high dose radiation directly to the cancer. PRRT has been significantly improve survival outcomes and maintain quality of life in metastatic disease. Suitability for PRRT depends on presence of SSTR2 as determined by PET imaging, commonly with [68Ga]-dotatate-PET. 20% of patients will have low or no uptake on [68Ga]-dotatate-PET precluding PRRT. The upstream promoter region of SSRT2 is methylated, with percentage of methylation correlating with SSTR2 expression. We have shown that the use of the demethylating agent, guadecitabine, increases uptake on PET imaging in such that tumours previously negative on PET imaging, become positive, correlating with a dose dependent increase in tumoural SSTR2 expression. Combination guadecitabine and PRRT was well tolerated in vivo models of NETs. Overall aim was to utilise [68Ga]-dotatate-PET as a biomarker of SSTR2 re-expression following treatment with the demethylating agent, ASTX727, such that patients previously unsuitable for PRRT can receive therapy, improving clinical outcome. 1) Utilise [68Ga]-dotatate-PET to image epigenetic regulation of SSTR2 in response to ASTX727. 2) Evaluate clinical efficacy and safety of ASTX727 pre-treatment in combination with PRRT. 3) Explore impact on quality of life of combination therapy. Methods: 27 patients with no or equivocal uptake on [68Ga]-dotatate-PET will be enrolled. [68Ga]-dotatate-PET will be performed at baseline and after 8days of ASTX727 (oral, fixed dose 100mg cedazuridine + 35mg decitabine). If there is a significant increase in PET uptake, patients will receive combination ASTX727 and PRRT (Lutathera). Treatment will be repeated every 2months for 4 cycles. Response assessment (RECIST 1.1), tolerability and QoL will be assessed at start of each cycle. Tumour biopsies will be taken at baseline, and after cycle1 of ASTX727 (n=5), for SSTR2 methylation. Methylation will be correlated with PET uptake and outcome. LINE-1 methylation in peripheral blood monocytes will be assessed throughout. Current enrolment: 4. Clinical trial information: NCT05178693 .
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Fleischmann, Achim, Beatrice Waser e Jean Claude Reubi. "High expression of gastrin-releasing peptide receptors in the vascular bed of urinary tract cancers: promising candidates for vascular targeting applications". Endocrine-Related Cancer 16, n.º 2 (junho de 2009): 623–33. http://dx.doi.org/10.1677/erc-08-0316.
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Tumoral gastrin-releasing peptide (GRP) receptors are potential targets for diagnosis and therapy using radiolabeled or cytotoxic GRP analogs. GRP-receptor overexpression has been detected in endocrine-related cancer cells and, more recently, also in the vascular bed of selected tumors. More information on vascular GRP-receptors in cancer is required to asses their potential for vascular targeting applications. Therefore, frequent human cancers (n=368) were analyzed using in vitro GRP-receptor autoradiography on tissue sections with the 125I-[Tyr4]-bombesin radioligand and/or the universal radioligand 125I-[d-Tyr6, β-Ala11, Phe13, Nle14]-bombesin(6–14). GRP-receptor expressing vessels were evaluated in each tumor group for prevalence, quantity (vascular score), and GRP-receptor density. Prevalence of vascular GRP-receptors was variable, ranging from 12% (prostate cancer) to 92% (urinary tract cancer). Different tumor types within a given site had divergent prevalence of vascular GRP-receptors (e.g. lung: small cell cancer: 0%; adenocarcinoma: 59%; squamous carcinoma: 83%). Also the vascular score varied widely, with the highest score in urinary tract cancer (1.69), moderate scores in lung (0.91), colon (0.88), kidney (0.84), and biliary tract (0.69) cancers and low scores in breast (0.39) and prostate (0.14) cancers. Vascular GRP-receptors were expressed in the muscular vessel wall in moderate to high densities. Normal non-neoplastic control tissues from these organs lacked vascular GRP-receptors. In conclusion, tumoral vessels in all evaluated sites express GRP-receptors, suggesting a major biological function of GRP-receptors in neovasculature. Vascular GRP-receptor expression varies between the tumor types indicating tumor-specific mechanisms in their regulation. Urinary tract cancers express vascular GRP-receptors so abundantly, that they are promising candidates for vascular targeting applications.
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Oh, Sowon, Vikas Prasad, Dong Soo Lee e R. P. Baum. "Effect of Peptide Receptor Radionuclide Therapy on Somatostatin Receptor Status and Glucose Metabolism in Neuroendocrine Tumors: Intraindividual Comparison of Ga-68 DOTANOC PET/CT and F-18 FDG PET/CT". International Journal of Molecular Imaging 2011 (9 de novembro de 2011): 1–7. http://dx.doi.org/10.1155/2011/524130.
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The heterogeneous nature of the neuroendocrine tumors (NET) makes it challenging to find one uniformly applicable management protocol which is especially true for diagnosis. The discovery of the overexpression of somatostatin receptors (SMS-R) on neuroendocrine tumor cells lead to the generalized and rapid acceptance of radiolabeled somatostatin receptor analogs for staging and restaging of NET as well as for Peptide Receptor Radionuclide Therapy (PRRNT) using Y-90 and Lu-177 DOTATATE/DOTATOC. In this present work we tried to look in to the effect of PRRNT on the glucose metabolism assessed by F-18 FDG PET/CT and SMS-R density assessed by Ga-68 DOTANOC PET/CT. We observed a complex relationship between the somatostatin receptor expression and glucose metabolism with only 56% (77/138) of the lesions showing match, while the others show mismatch between the receptor status and metabolism. The match between receptor expression and glucose metabolism increases with the grade of NET. In grade 3 NET, there is a concurrence between the changes in glucose metabolism and somatostatin receptor expression. PRRNT was found to be more effective in lesions with higher receptor expression.
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Salavati, Ali, Ameya Puranik, Harshad R. Kulkarni, Hendra Budiawan e Richard P. Baum. "Peptide Receptor Radionuclide Therapy (PRRT) of Medullary and Nonmedullary Thyroid Cancer Using Radiolabeled Somatostatin Analogues". Seminars in Nuclear Medicine 46, n.º 3 (maio de 2016): 215–24. http://dx.doi.org/10.1053/j.semnuclmed.2016.01.010.
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Kristiansson, Amanda, Anders Örbom, Oskar Vilhelmsson Timmermand, Jonas Ahlstedt, Sven-Erik Strand e Bo Åkerström. "Kidney Protection with the Radical Scavenger α1-Microglobulin (A1M) during Peptide Receptor Radionuclide and Radioligand Therapy". Antioxidants 10, n.º 8 (10 de agosto de 2021): 1271. http://dx.doi.org/10.3390/antiox10081271.
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α1-Microglobulin (A1M) is an antioxidant found in all vertebrates, including humans. It has enzymatic reductase activity and can scavenge radicals and bind free heme groups. Infused recombinant A1M accumulates in the kidneys and has therefore been successful in protecting kidney injuries in different animal models. In this review, we focus on A1M as a radioprotector of the kidneys during peptide receptor radionuclide/radioligand therapy (PRRT/RLT). Patients with, e.g., neuroendocrine tumors or castration resistant prostate cancer can be treated by administration of radiolabeled small molecules which target and therefore enable the irradiation and killing of cancer cells through specific receptor interaction. The treatment is not curative, and kidney toxicity has been reported as a side effect since the small, radiolabeled substances are retained and excreted through the kidneys. In recent studies, A1M was shown to have radioprotective effects on cell cultures as well as having a similar biodistribution as the somatostatin analogue peptide 177Lu-DOTATATE after intravenous infusion in mice. Therefore, several animal studies were conducted to investigate the in vivo radioprotective potential of A1M towards kidneys. The results of these studies demonstrated that A1M co-infusion yielded protection against kidney toxicity and improved overall survival in mouse models. Moreover, two different mouse studies reported that A1M did not interfere with tumor treatment itself. Here, we give an overview of radionuclide therapy, the A1M physiology and the results from the radioprotector studies of the protein.