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Kilian K, Pyrzyńska K. Scandium Radioisotopes-Toward New Targets and Imaging Modalities. Molecules 2023; 28:7668. [PMID: 38005390 PMCID: PMC10675654 DOI: 10.3390/molecules28227668] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 11/15/2023] [Accepted: 11/15/2023] [Indexed: 11/26/2023] Open
Abstract
The concept of theranostics uses radioisotopes of the same or chemically similar elements to label biological ligands in a way that allows the use of diagnostic and therapeutic radiation for a combined diagnosis and treatment regimen. For scandium, radioisotopes -43 and -44 can be used as diagnostic markers, while radioisotope scandium-47 can be used in the same configuration for targeted therapy. This work presents the latest achievements in the production and processing of radioisotopes and briefly characterizes solutions aimed at increasing the availability of these radioisotopes for research and clinical practice.
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Affiliation(s)
- Krzysztof Kilian
- Heavy Ion Laboratory, University of Warsaw, Pasteura 5a, 02-093 Warsaw, Poland
| | - Krystyna Pyrzyńska
- Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland;
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2
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Becker KV, Aluicio-Sarduy E, Bradshaw T, Hurley SA, Olson AP, Barrett KE, Batterton J, Ellison PA, Barnhart TE, Pirasteh A, Engle JW. Cyclotron production of 43Sc and 44gSc from enriched 42CaO, 43CaO, and 44CaO targets. Front Chem 2023; 11:1167783. [PMID: 37179772 PMCID: PMC10169720 DOI: 10.3389/fchem.2023.1167783] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 04/18/2023] [Indexed: 05/15/2023] Open
Abstract
Introduction: 43Sc and 44gSc are both positron-emitting radioisotopes of scandium with suitable half-lives and favorable positron energies for clinical positron emission tomography (PET) imaging. Irradiation of isotopically enriched calcium targets has higher cross sections compared to titanium targets and higher radionuclidic purity and cross sections than natural calcium targets for reaction routes possible on small cyclotrons capable of accelerating protons and deuterons. Methods: In this work, we investigate the following production routes via proton and deuteron bombardment on CaCO3 and CaO target materials: 42Ca(d,n)43Sc, 43Ca(p,n)43Sc, 43Ca(d,n)44gSc, 44Ca(p,n)44gSc, and 44Ca(p,2n)43Sc. Radiochemical isolation of the produced radioscandium was performed with extraction chromatography using branched DGA resin and apparent molar activity was measured with the chelator DOTA. The imaging performance of 43Sc and 44gSc was compared with 18F, 68Ga, and 64Cu on two clinical PET/CT scanners. Discussion: The results of this work demonstrate that proton and deuteron bombardment of isotopically enriched CaO targets produce high yield and high radionuclidic purity 43Sc and 44gSc. Laboratory capabilities, circumstances, and budgets are likely to dictate which reaction route and radioisotope of scandium is chosen.
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Affiliation(s)
- Kaelyn V. Becker
- Department of Medical Physics, University of Wisconsin, Madison, WI, United States
| | | | - Tyler Bradshaw
- Department of Radiology, University of Wisconsin, Madison, WI, United States
| | - Samuel A. Hurley
- Department of Radiology, University of Wisconsin, Madison, WI, United States
| | - Aeli P. Olson
- Department of Medical Physics, University of Wisconsin, Madison, WI, United States
| | - Kendall E. Barrett
- Department of Medical Physics, University of Wisconsin, Madison, WI, United States
| | - Jeanine Batterton
- Department of Radiology, University of Wisconsin, Madison, WI, United States
| | - Paul A. Ellison
- Department of Medical Physics, University of Wisconsin, Madison, WI, United States
| | - Todd E. Barnhart
- Department of Medical Physics, University of Wisconsin, Madison, WI, United States
| | - Ali Pirasteh
- Department of Radiology, University of Wisconsin, Madison, WI, United States
| | - Jonathan W. Engle
- Department of Medical Physics, University of Wisconsin, Madison, WI, United States
- Department of Radiology, University of Wisconsin, Madison, WI, United States
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3
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Modern Developments in Bifunctional Chelator Design for Gallium Radiopharmaceuticals. MOLECULES (BASEL, SWITZERLAND) 2022; 28:molecules28010203. [PMID: 36615397 PMCID: PMC9822085 DOI: 10.3390/molecules28010203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 12/19/2022] [Accepted: 12/19/2022] [Indexed: 12/28/2022]
Abstract
The positron-emitting radionuclide gallium-68 has become increasingly utilised in both preclinical and clinical settings with positron emission tomography (PET). The synthesis of radiochemically pure gallium-68 radiopharmaceuticals relies on careful consideration of the coordination chemistry. The short half-life of 68 min necessitates rapid quantitative radiolabelling (≤10 min). Desirable radiolabelling conditions include near-neutral pH, ambient temperatures, and low chelator concentrations to achieve the desired apparent molar activity. This review presents a broad overview of the requirements of an efficient bifunctional chelator in relation to the aqueous coordination chemistry of gallium. Developments in bifunctional chelator design and application are then presented and grouped according to eight categories of bifunctional chelator: the macrocyclic chelators DOTA and TACN; the acyclic HBED, pyridinecarboxylates, siderophores, tris(hydroxypyridinones), and DTPA; and the mesocyclic diazepines.
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4
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Wongso H, Hendra R, Nugraha AS, Ritawidya R, Saptiama I, Kusumaningrum CE. Microbial metabolites diversity and their potential as molecular template for the discovery of new fluorescent and radiopharmaceutical probes. Trends Analyt Chem 2022. [DOI: 10.1016/j.trac.2022.116900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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5
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Jeitner TM, Babich JW, Kelly JM. Advances in PSMA theranostics. Transl Oncol 2022; 22:101450. [PMID: 35597190 PMCID: PMC9123266 DOI: 10.1016/j.tranon.2022.101450] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 05/04/2022] [Accepted: 05/08/2022] [Indexed: 12/15/2022] Open
Abstract
PSMA is an appealing target for theranostic because it is a transmembrane protein with a known substrate that is overexpessed on prostate cancer cells and internalizes upon ligand binding. There are a number of PSMA theranostic ligands in clinical evaluation, clinical trial, or clinically approved. PSMA theranostic ligands increase progression-free survival, overall survival, and pain in patients with metastatic castration resistant prostate cancer. A major obstacle to PSMA-targeted radioligand therapy is off-target toxicity in salivary glands.
The validation of prostate specific membrane antigen (PSMA) as a molecular target in metastatic castration-resistant prostate cancer has stimulated the development of multiple classes of theranostic ligands that specifically target PSMA. Theranostic ligands are used to image disease or selectively deliver cytotoxic radioactivity to cells expressing PSMA according to the radioisotope conjugated to the ligand. PSMA theranostics is a rapidly advancing field that is now integrating into clinical management of prostate cancer patients. In this review we summarize published research describing the biological role(s) and activity of PSMA, highlight the most clinically advanced PSMA targeting molecules and biomacromolecules, and identify next generation PSMA ligands that aim to further improve treatment efficacy. The goal of this review is to provide a comprehensive assessment of the current state-of-play and a roadmap to achieving further advances in PSMA theranostics.
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Affiliation(s)
- Thomas M Jeitner
- Molecular Imaging Innovations Institute, Department of Radiology, Weill Cornell Medicine, Belfer Research Building, 413 East 69th Street, Room BB-1604, New York, NY 10021, USA
| | - John W Babich
- Molecular Imaging Innovations Institute, Department of Radiology, Weill Cornell Medicine, Belfer Research Building, 413 East 69th Street, Room BB-1604, New York, NY 10021, USA; Weill Cornell Medicine, Sandra and Edward Meyer Cancer Center, New York, NY 10021, USA; Weill Cornell Medicine, Citigroup Biomedical Imaging Center, New York, NY 10021, USA
| | - James M Kelly
- Molecular Imaging Innovations Institute, Department of Radiology, Weill Cornell Medicine, Belfer Research Building, 413 East 69th Street, Room BB-1604, New York, NY 10021, USA; Weill Cornell Medicine, Citigroup Biomedical Imaging Center, New York, NY 10021, USA.
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6
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Wu Y, Zhang X, Zhou H, Zhang J. Preclinical development of a novel [68Ga]Ga-/[177Lu]Lu-labeled agent for PSMA-targeted imaging and therapy. J Radioanal Nucl Chem 2022. [DOI: 10.1007/s10967-022-08301-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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7
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Fersing C, Masurier N, Rubira L, Deshayes E, Lisowski V. AAZTA-Derived Chelators for the Design of Innovative Radiopharmaceuticals with Theranostic Applications. Pharmaceuticals (Basel) 2022; 15:234. [PMID: 35215346 PMCID: PMC8879111 DOI: 10.3390/ph15020234] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 02/12/2022] [Accepted: 02/14/2022] [Indexed: 02/06/2023] Open
Abstract
With the development of 68Ga and 177Lu radiochemistry, theranostic approaches in modern nuclear medicine enabling patient-centered personalized medicine applications have been growing in the last decade. In conjunction with the search for new relevant molecular targets, the design of innovative chelating agents to easily form stable complexes with various radiometals for theranostic applications has gained evident momentum. Initially conceived for magnetic resonance imaging applications, the chelating agent AAZTA features a mesocyclic seven-membered diazepane ring, conferring some of the properties of both acyclic and macrocyclic chelating agents. Described in the early 2000s, AAZTA and its derivatives exhibited interesting properties once complexed with metals and radiometals, combining a fast kinetic of formation with a slow kinetic of dissociation. Importantly, the extremely short coordination reaction times allowed by AAZTA derivatives were particularly suitable for short half-life radioelements (i.e., 68Ga). In view of these particular characteristics, the scope of this review is to provide a survey on the design, synthesis, and applications in the nuclear medicine/radiopharmacy field of AAZTA-derived chelators.
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Affiliation(s)
- Cyril Fersing
- Nuclear Medicine Department, Institut Régional du Cancer de Montpellier (ICM), University Montpellier, 34298 Montpellier, France; (L.R.); (E.D.)
- IBMM, University Montpellier, CNRS, ENSCM, 34293 Montpellier, France; (N.M.); (V.L.)
| | - Nicolas Masurier
- IBMM, University Montpellier, CNRS, ENSCM, 34293 Montpellier, France; (N.M.); (V.L.)
| | - Léa Rubira
- Nuclear Medicine Department, Institut Régional du Cancer de Montpellier (ICM), University Montpellier, 34298 Montpellier, France; (L.R.); (E.D.)
| | - Emmanuel Deshayes
- Nuclear Medicine Department, Institut Régional du Cancer de Montpellier (ICM), University Montpellier, 34298 Montpellier, France; (L.R.); (E.D.)
- Institut de Recherche en Cancérologie de Montpellier (IRCM), INSERM U1194, Institut Régional du Cancer de Montpellier (ICM), University of Montpellier, 34298 Montpellier, France
| | - Vincent Lisowski
- IBMM, University Montpellier, CNRS, ENSCM, 34293 Montpellier, France; (N.M.); (V.L.)
- Department of Pharmacy, Lapeyronie Hospital, CHU Montpellier, 191 Av. du Doyen Gaston Giraud, 34295 Montpellier, France
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Lepareur N. Cold Kit Labeling: The Future of 68Ga Radiopharmaceuticals? Front Med (Lausanne) 2022; 9:812050. [PMID: 35223907 PMCID: PMC8869247 DOI: 10.3389/fmed.2022.812050] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 01/07/2022] [Indexed: 12/11/2022] Open
Abstract
Over the last couple of decades, gallium-68 (68Ga) has gained a formidable interest for PET molecular imaging of various conditions, from cancer to infection, through cardiac pathologies or neuropathies. It has gained routine use, with successful radiopharmaceuticals such as somatostatin analogs ([68Ga]Ga-DOTATOC and [68Ga]GaDOTATATE) for neuroendocrine tumors, and PSMA ligands for prostate cancer. It represents a major clinical impact, particularly in the context of theranostics, coupled with their 177Lu-labeled counterparts. Beside those, a bunch of new 68Ga-labeled molecules are in the preclinical and clinical pipelines, with some of them showing great promise for patient care. Increasing clinical demand and regulatory issues have led to the development of automated procedures for the production of 68Ga radiopharmaceuticals. However, the widespread use of these radiopharmaceuticals may rely on simple and efficient radiolabeling methods, undemanding in terms of equipment and infrastructure. To make them technically and economically accessible to the medical community and its patients, it appears mandatory to develop a procedure similar to the well-established kit-based 99mTc chemistry. Already available commercial kits for the production of 68Ga radiopharmaceuticals have demonstrated the feasibility of using such an approach, thus paving the way for more kit-based 68Ga radiopharmaceuticals to be developed. This article discusses the development of 68Ga cold kit radiopharmacy, including technical issues, and regulatory aspects.
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Affiliation(s)
- Nicolas Lepareur
- Comprehensive Cancer Center Eugène Marquis, Rennes, France
- Univ Rennes, Inrae, Inserm, Institut NUMECAN (Nutrition, Métabolismes et Cancer), UMR_A 1341, UMR_S 1241, Rennes, France
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Lee H. Relative Efficacy of 225Ac-PSMA-617 and 177Lu-PSMA-617 in Prostate Cancer Based on Subcellular Dosimetry. Mol Imaging Radionucl Ther 2022; 31:1-6. [PMID: 35114745 PMCID: PMC8814544 DOI: 10.4274/mirt.galenos.2021.63308] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Objectives: Radionuclide therapy targeting prostate-specific membrane antigen (PSMA) with alpha-emitting 225Ac-PSMA-617 has shown clinical efficacy even in cases of failed therapy with beta-emitting 177Lu-PSMA-617. We investigated the efficacy of 225Ac-PSMA-617 relative to 177Lu-PSMA-617 using subcellular dosimetry. Methods: A 3-dimensional model of prostate cancer was constructed. For each decay, the absorbed and equivalent radiation dose to the cell nuclei was calculated. The relative efficacy per administered activity was calculated by taking into account the differences in residence time and tumor uptake. Results: As the tumor size increased, the absorbed dose from 225Ac-PSMA-617 increased linearly (R2: 0.99) and reached an asymptote near the maximum alpha range (85 µm), whereas the absorbed dose from 177Lu-PSMA-617 continued to increase linearly (R2: 0.99). The equivalent dose per decay was 2,320, 2,900, and 823-fold higher in favor of 225Ac-PSMA-617 compared to 177Lu-PSMA-617 in a single cell, 100 µm-radius micrometastasis, and macroscopic tumor, respectively. Per administered activity, the relative efficacy of 225Ac-PSMA-617 compared to 177Lu-PSMA-617 in respective tumor sizes was at least 3,480, 4,350, and 1,230-fold higher, and possibly 11,800, 14,900, and 4,200-fold higher considering differences in tumor uptake. Conclusion: At commonly administered 1,000-fold lower activity of 225Ac-PSMA-617 relative to 177Lu-PSMA-617, the equivalent radiation dose deposited by 225Ac-PSMA-617 is higher in measurable disease and much higher in microscopic disease compared to 177Lu-PSMA-617.
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Affiliation(s)
- Hwan Lee
- University of Pennsylvania Perelman School of Medicine, Department of Radiology, Philadelphia, United States
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10
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Griffiths GL, Vasquez C, Escorcia F, Clanton J, Lindenberg L, Mena E, Choyke PL. Translating a radiolabeled imaging agent to the clinic. Adv Drug Deliv Rev 2022; 181:114086. [PMID: 34942275 PMCID: PMC8889912 DOI: 10.1016/j.addr.2021.114086] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 11/30/2021] [Accepted: 12/16/2021] [Indexed: 02/03/2023]
Abstract
Molecular Imaging is entering the most fruitful, exciting period in its history with many new agents under development, and several reaching the clinic in recent years. While it is unusual for just one laboratory to take an agent from initial discovery through to full clinical approval the steps along the way are important to understand for all interested participants even if one is not involved in the entire process. Here, we provide an overview of these processes beginning at discovery and preclinical validation of a new molecular imaging agent and using as an exemplar a low molecular weight disease-specific targeted positron emission tomography (PET) agent. Compared to standard drug development requirements, molecular imaging agents may benefit from a regulatory standpoint from their low mass administered doses, they nonetheless still need to go through a series of well-defined steps before they can be considered for Phase 1 human testing. After outlining the discovery and preclinical validation approaches, we will also discuss the nuances of Phase 1, Phase 2 and Phase 3 studies that may culminate in an FDA general use approval. Finally, some post-approval aspects of novel molecular imaging agents are considered.
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Affiliation(s)
- Gary L. Griffiths
- Clinical Research Directorate, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Frederick, MD
| | - Crystal Vasquez
- Molecular Imaging Branch, National Cancer Institute, Bethesda, MD
| | - Freddy Escorcia
- Molecular Imaging Branch, National Cancer Institute, Bethesda, MD
| | | | - Liza Lindenberg
- Molecular Imaging Branch, National Cancer Institute, Bethesda, MD
| | - Esther Mena
- Molecular Imaging Branch, National Cancer Institute, Bethesda, MD
| | - Peter L. Choyke
- Molecular Imaging Branch, National Cancer Institute, Bethesda, MD
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Martinelli J, Boccalon M, Horvath D, Esteban-Gomez D, Platas-Iglesias C, Baranyai Z, Tei L. The critical role of ligand topology: strikingly different properties of Gd( iii) complexes with regioisomeric AAZTA derivatives. Inorg Chem Front 2022. [DOI: 10.1039/d2qi00451h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Two regioisomeric Gd(III) complexes with heptadentate AAZTA-like ligands show different hydration state (q = 1 and 2) and astonishingly different thermodynamic stability and dissociation kinetics.
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Affiliation(s)
- Jonathan Martinelli
- Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte Orientale “A. Avogadro”, Viale T. Michel 11, 15121 Alessandria, Italy
| | - Mariangela Boccalon
- Bracco Research Centre, Bracco Imaging S.p.A., Via Ribes 5, 10010, Colleretto Giacosa, Italy
| | - David Horvath
- Bracco Research Centre, Bracco Imaging S.p.A., Via Ribes 5, 10010, Colleretto Giacosa, Italy
- University of Debrecen, Faculty of Science and Technology, Department of Physical Chemistry, Doctoral School of Chemistry, Debrecen, Hungary
| | - David Esteban-Gomez
- Universidade da Coruña, Centro de Investigacións Científicas Avanzadas (CICA) and Departamento de Química Fundamental, Facultade de Ciencias, 15071, A Coruña, Galicia, Spain
| | - Carlos Platas-Iglesias
- Universidade da Coruña, Centro de Investigacións Científicas Avanzadas (CICA) and Departamento de Química Fundamental, Facultade de Ciencias, 15071, A Coruña, Galicia, Spain
| | - Zsolt Baranyai
- Bracco Research Centre, Bracco Imaging S.p.A., Via Ribes 5, 10010, Colleretto Giacosa, Italy
| | - Lorenzo Tei
- Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte Orientale “A. Avogadro”, Viale T. Michel 11, 15121 Alessandria, Italy
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Chakravarty R, Chakraborty S. A review of advances in the last decade on targeted cancer therapy using 177Lu: focusing on 177Lu produced by the direct neutron activation route. AMERICAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING 2021; 11:443-475. [PMID: 35003885 PMCID: PMC8727880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 10/09/2021] [Indexed: 06/14/2023]
Abstract
Lutetium-177 [T½ = 6.76 d; Eβ (max) = 0.497 MeV; maximum tissue range ~2.5 mm; 208 keV γ-ray] is one of the most important theranostic radioisotope used for the management of various oncological and non-oncological disorders. The present review chronicles the advancement in the last decade in 177Lu-radiopharmacy with a focus on 177Lu produced via direct 176Lu (n, γ) 177Lu nuclear reaction in medium flux research reactors. The specific nuances of 177Lu production by various routes are described and their pros and cons are discussed. Lutetium, is the last element in the lanthanide series. Its chemistry plays a vital role in the preparation of a wide variety of radiopharmaceuticals which demonstrate appreciable in vivo stability. Traditional bifunctional chelators (BFCs) that are used for 177Lu-labeling are discussed and the upcoming ones are highlighted. Research efforts that resulted in the growth of various 177Lu-based radiopharmaceuticals in preclinical and clinical settings are provided. This review also summarizes the results of clinical studies with potent 177Lu-based radiopharmaceuticals that have been prepared using medium specific activity 177Lu produced by direct neutron activation route in research reactors. Overall, the review amply demonstrates the practicality of the medium specific activity 177Lu towards formulation of various clinically useful radiopharmaceuticals, especially for the benefit of millions of cancer patients in developing countries with limited reactor facilities.
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Affiliation(s)
- Rubel Chakravarty
- Radiopharmaceuticals Division, Bhabha Atomic Research Centre Trombay, Mumbai 400085, India
- Homi Bhabha National Institute Anushaktinagar, Mumbai 400094, India
| | - Sudipta Chakraborty
- Radiopharmaceuticals Division, Bhabha Atomic Research Centre Trombay, Mumbai 400085, India
- Homi Bhabha National Institute Anushaktinagar, Mumbai 400094, India
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Lahnif H, Grus T, Pektor S, Greifenstein L, Schreckenberger M, Rösch F. Hybrid Chelator-Based PSMA Radiopharmaceuticals: Translational Approach. Molecules 2021; 26:molecules26216332. [PMID: 34770742 PMCID: PMC8588462 DOI: 10.3390/molecules26216332] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 10/15/2021] [Accepted: 10/18/2021] [Indexed: 01/22/2023] Open
Abstract
(1) Background: Prostate-specific membrane antigen (PSMA) has been extensively studied in the last decade. It became a promising biological target in the diagnosis and therapy of PSMA-expressing cancer diseases. Although there are several radiolabeled PSMA inhibitors available, the search for new compounds with improved pharmacokinetic properties and simplified synthesis is still ongoing. In this study, we developed PSMA ligands with two different hybrid chelators and a modified linker. Both compounds have displayed a promising pharmacokinetic profile. (2) Methods: DATA5m.SA.KuE and AAZTA5.SA.KuE were synthesized. DATA5m.SA.KuE was labeled with gallium-68 and radiochemical yields of various amounts of precursor at different temperatures were determined. Complex stability in phosphate-buffered saline (PBS) and human serum (HS) was examined at 37 °C. Binding affinity and internalization ratio were determined in in vitro assays using PSMA-positive LNCaP cells. Tumor accumulation and biodistribution were evaluated in vivo and ex vivo using an LNCaP Balb/c nude mouse model. All experiments were conducted with PSMA-11 as reference. (3) Results: DATA5m.SA.KuE was synthesized successfully. AAZTA5.SA.KuE was synthesized and labeled according to the literature. Radiolabeling of DATA5m.SA.KuE with gallium-68 was performed in ammonium acetate buffer (1 M, pH 5.5). High radiochemical yields (>98%) were obtained with 5 nmol at 70 °C, 15 nmol at 50 °C, and 60 nmol (50 µg) at room temperature. [68Ga]Ga-DATA5m.SA.KuE was stable in human serum as well as in PBS after 120 min. PSMA binding affinities of AAZTA5.SA.KuE and DATA5m.SA.KuE were in the nanomolar range. PSMA-specific internalization ratio was comparable to PSMA-11. In vivo and ex vivo studies of [177Lu]Lu-AAZTA5.SA.KuE, [44Sc]Sc-AAZTA5.SA.KuE and [68Ga]Ga-DATA5m.SA.KuE displayed specific accumulation in the tumor along with fast clearance and reduced off-target uptake. (4) Conclusions: Both KuE-conjugates showed promising properties especially in vivo allowing for translational theranostic use.
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Affiliation(s)
- Hanane Lahnif
- Department of Chemistry—TRIGA Site, Johannes Gutenberg University Mainz, 55128 Mainz, Germany; (H.L.); (T.G.); (L.G.)
| | - Tilmann Grus
- Department of Chemistry—TRIGA Site, Johannes Gutenberg University Mainz, 55128 Mainz, Germany; (H.L.); (T.G.); (L.G.)
| | - Stefanie Pektor
- Department of Nuclear Medicine, University Medical Center Mainz, 55131 Mainz, Germany; (S.P.); (M.S.)
| | - Lukas Greifenstein
- Department of Chemistry—TRIGA Site, Johannes Gutenberg University Mainz, 55128 Mainz, Germany; (H.L.); (T.G.); (L.G.)
- Curanosticum Wiesbaden–Frankfurt, 65191 Wiesbaden, Germany
| | - Mathias Schreckenberger
- Department of Nuclear Medicine, University Medical Center Mainz, 55131 Mainz, Germany; (S.P.); (M.S.)
| | - Frank Rösch
- Department of Chemistry—TRIGA Site, Johannes Gutenberg University Mainz, 55128 Mainz, Germany; (H.L.); (T.G.); (L.G.)
- Correspondence: ; Tel.: +49-6131-39-25302
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Fifty Shades of Scandium: Comparative Study of PET Capabilities Using Sc-43 and Sc-44 with Respect to Conventional Clinical Radionuclides. Diagnostics (Basel) 2021; 11:diagnostics11101826. [PMID: 34679525 PMCID: PMC8535161 DOI: 10.3390/diagnostics11101826] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 09/28/2021] [Accepted: 09/29/2021] [Indexed: 11/16/2022] Open
Abstract
Scandium-44 has been proposed as a valuable radionuclide for Positron Emission Tomography (PET). Recently, scandium-43 was introduced as a more favorable option, as it does not emit high-energy γ-radiation; however, its currently employed production method results in a mixture of scandium-43 and scandium-44. The interest in new radionuclides for diagnostic nuclear medicine critically depends on the option for image-based quantification. We aimed to evaluate and compare the quantitative capabilities of scandium-43/scandium-44 in a commercial PET/CT device with respect to more conventional clinical radionuclides (fluorine-18 and gallium-68). With this purpose, we characterized and compared quantitative PET data from a mixture of scandium-43/scandium-44 (~68% scandium-43), scandium-44, fluorine-18 and gallium-68, respectively. A NEMA image-quality phantom was filled with the different radionuclides using clinical-relevant lesion-to-background activity concentration ratios; images were acquired in a Siemens Biograph Vision PET/CT. Quantitative accuracy with scandium-43/scandium-44 in the phantom's background was within 9%, which is in agreement with fluorine-18-based PET standards. Coefficient of variance (COV) was 6.32% and signal recovery in the lesions provided RCmax (recovery coefficient) values of 0.66, 0.90, 1.03, 1.04, 1.12 and 1.11 for lesions of 10-, 13-, 17-, 22-, 28- and 37-mm diameter, respectively. These results are in agreement with EARL reference values for fluorine-18 PET. The results in this work showed that accurate quantitative scandium-43/44 PET/CT is achievable in commercial devices. This may promote the future introduction of scandium-43/44-labelled radiopharmaceuticals into clinical use.
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Travagin F, Lattuada L, Giovenzana GB. AAZTA: The rise of mesocyclic chelating agents for metal coordination in medicine. Coord Chem Rev 2021. [DOI: 10.1016/j.ccr.2021.213908] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Advances in Development of Radiometal Labeled Amino Acid-Based Compounds for Cancer Imaging and Diagnostics. Pharmaceuticals (Basel) 2021; 14:ph14020167. [PMID: 33669938 PMCID: PMC7924883 DOI: 10.3390/ph14020167] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 02/13/2021] [Accepted: 02/18/2021] [Indexed: 02/08/2023] Open
Abstract
Radiolabeled biomolecules targeted at tumor-specific enzymes, receptors, and transporters in cancer cells represent an intensively investigated and promising class of molecular tools for the cancer diagnosis and therapy. High specificity of such biomolecules is a prerequisite for the treatment with a lower burden to normal cells and for the effective and targeted imaging and diagnosis. Undoubtedly, early detection is a key factor in efficient dealing with many severe tumor types. This review provides an overview and critical evaluation of novel approaches in the designing of target-specific probes labeled with metal radionuclides for the diagnosis of most common death-causing cancers, published mainly within the last three years. Advances are discussed such traditional peptide radiolabeling approaches, and click and nanoparticle chemistry. The progress of radiolabeled peptide based ligands as potential radiopharmaceuticals is illustrated via novel structure and application studies, showing how the molecular modifications reflect their binding selectivity to significant onco-receptors, toxicity, and, by that, practical utilization. The most impressive outputs in categories of newly developed structures, as well as imaging and diagnosis approaches, and the most intensively studied oncological diseases in this context, are emphasized in order to show future perspectives of radiometal labeled amino acid-based compounds in nuclear medicine.
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