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Ndlovu H, Mokoala KMG, Lawal I, Emmett L, Sathekge MM. Prostate-specific Membrane Antigen: Alpha-labeled Radiopharmaceuticals. PET Clin 2024; 19:371-388. [PMID: 38658230 DOI: 10.1016/j.cpet.2024.03.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
Novel prostate-specific membrane antigen (PSMA) ligands labeled with α-emitting radionuclides are sparking a growing interest in prostate cancer treatment. These targeted alpha therapies (TATs) have attractive physical properties that deem them effective in progressive metastatic castrate-resistant prostate cancer (mCRPC). Among the PSMA TAT radiopharmaceuticals, [225Ac]Ac-PSMA has been used extensively on a compassionate basis and is currently undergoing phase I trials. Notably, TAT has the potential to improve quality of life and has favorable antitumor activity and outcomes in multiple scenarios other than in mCRPC. In addition, resistance mechanisms to TAT may be amenable to combination therapies.
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Affiliation(s)
- Honest Ndlovu
- Nuclear Medicine Research Infrastructure (NuMeRI), Steve Biko Academic Hospital, Pretoria, South Africa; Department of Nuclear Medicine, University of Pretoria & Steve Biko Academic Hospital, Pretoria, South Africa
| | - Kgomotso M G Mokoala
- Nuclear Medicine Research Infrastructure (NuMeRI), Steve Biko Academic Hospital, Pretoria, South Africa; Department of Nuclear Medicine, University of Pretoria & Steve Biko Academic Hospital, Pretoria, South Africa
| | - Ismaheel Lawal
- Department of Nuclear Medicine, University of Pretoria & Steve Biko Academic Hospital, Pretoria, South Africa; Department of Radiology and Imaging Sciences, Emory University, Atlanta, GA, USA
| | - Louise Emmett
- Theranostics and Nuclear Medicine, St Vincent's Hospital Sydney, Australia
| | - Mike M Sathekge
- Nuclear Medicine Research Infrastructure (NuMeRI), Steve Biko Academic Hospital, Pretoria, South Africa; Department of Nuclear Medicine, University of Pretoria & Steve Biko Academic Hospital, Pretoria, South Africa.
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2
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Schatz CA, Zitzmann-Kolbe S, Moen I, Klotz M, Nair S, Stargard S, Bjerke RM, Wickstrøm Biseth K, Feng YZ, Indrevoll B, Cruciani V, Karlsson J, Haendler B, Nielsen CH, Alfsen MZ, Hammer S, Hennekes H, Cuthbertson A, Hagemann UB, Larsen Å. Preclinical Efficacy of a PSMA-Targeted Actinium-225 Conjugate (225Ac-Macropa-Pelgifatamab): A Targeted Alpha Therapy for Prostate Cancer. Clin Cancer Res 2024; 30:2531-2544. [PMID: 38593212 DOI: 10.1158/1078-0432.ccr-23-3746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 02/07/2024] [Accepted: 04/03/2024] [Indexed: 04/11/2024]
Abstract
PURPOSE Initially, prostate cancer responds to hormone therapy, but eventually resistance develops. Beta emitter-based prostate-specific membrane antigen (PSMA)-targeted radionuclide therapy is approved for the treatment of metastatic castration-resistant prostate cancer. Here we introduce a targeted alpha therapy (TAT) consisting of the PSMA antibody pelgifatamab covalently linked to a macropa chelator and labeled with actinium-225 and compare its efficacy and tolerability with other TATs. EXPERIMENTAL DESIGN The in vitro characteristics and in vivo biodistribution, antitumor efficacy, and tolerability of 225Ac-macropa-pelgifatamab (225Ac-pelgi) and other TATs were investigated in cell line- and patient-derived prostate cancer xenograft models. The antitumor efficacy of 225Ac-pelgi was also investigated in combination with the androgen receptor inhibitor darolutamide. RESULTS Actinium-225-labeling of 225Ac-pelgi was efficient already at room temperature. Potent in vitro cytotoxicity was seen in PSMA-expressing (LNCaP, MDA-PCa-2b, and C4-2) but not in PSMA-negative (PC-3 and DU-145) cell lines. High tumor accumulation was seen for both 225Ac-pelgi and 225Ac-DOTA-pelgi in the MDA-PCa-2b xenograft model. In the C4-2 xenograft model, 225Ac-pelgi showed enhanced antitumor efficacy with a T/Cvolume (treatment/control) ratio of 0.10 compared with 225Ac-DOTA-pelgi, 225Ac-DOTA-J591, and 227Th-HOPO-pelgifatamab (227Th-pelgi; all at 300 kBq/kg) with T/Cvolume ratios of 0.37, 0.39, and 0.33, respectively. 225Ac-pelgi was less myelosuppressive than 227Th-pelgi. 225Ac-pelgi showed dose-dependent treatment efficacy in the patient-derived KuCaP-1 model and strong combination potential with darolutamide in both cell line- (22Rv1) and patient-derived (ST1273) xenograft models. CONCLUSIONS These results provide a strong rationale to investigate 225Ac-pelgi in patients with prostate cancer. A clinical phase I study has been initiated (NCT06052306).
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Bidkar AP, Zerefa L, Yadav S, VanBrocklin HF, Flavell RR. Actinium-225 targeted alpha particle therapy for prostate cancer. Theranostics 2024; 14:2969-2992. [PMID: 38773983 PMCID: PMC11103494 DOI: 10.7150/thno.96403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Accepted: 05/01/2024] [Indexed: 05/24/2024] Open
Abstract
Targeted alpha particle therapy (TAT) has emerged as a promising strategy for the treatment of prostate cancer (PCa). Actinium-225 (225Ac), a potent alpha-emitting radionuclide, may be incorporated into targeting vectors, causing robust and in some cases sustained antitumor responses. The development of radiolabeling techniques involving EDTA, DOTA, DOTPA, and Macropa chelators has laid the groundwork for advancements in this field. At the forefront of clinical trials with 225Ac in PCa are PSMA-targeted TAT agents, notably [225Ac]Ac-PSMA-617, [225Ac]Ac-PSMA-I&T and [225Ac]Ac-J591. Ongoing investigations spotlight [225Ac]Ac-hu11B6, [225Ac]Ac-YS5, and [225Ac]Ac-SibuDAB, targeting hK2, CD46, and PSMA, respectively. Despite these efforts, hurdles in 225Ac production, daughter redistribution, and a lack of suitable imaging techniques hinder the development of TAT. To address these challenges and additional advantages, researchers are exploring alpha-emitting isotopes including 227Th, 223Ra, 211At, 213Bi, 212Pb or 149Tb, providing viable alternatives for TAT.
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Affiliation(s)
- Anil P. Bidkar
- Department of Radiology and Biomedical Imaging, University of California San Francisco, CA-94107, USA
| | - Luann Zerefa
- Department of Radiology and Biomedical Imaging, University of California San Francisco, CA-94107, USA
| | - Surekha Yadav
- Department of Radiology and Biomedical Imaging, University of California San Francisco, CA-94107, USA
| | - Henry F. VanBrocklin
- Department of Radiology and Biomedical Imaging, University of California San Francisco, CA-94107, USA
- UCSF Helen Diller Family Comprehensive Cancer Center, San Francisco, CA-94107, USA
| | - Robert R. Flavell
- Department of Radiology and Biomedical Imaging, University of California San Francisco, CA-94107, USA
- UCSF Helen Diller Family Comprehensive Cancer Center, San Francisco, CA-94107, USA
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA-94107, USA
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4
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Böhnke N, Indrevoll B, Hammer S, Papple A, Kristian A, Briem H, Celik A, Mumberg D, Cuthbertson A, Zitzmann-Kolbe S. Mono- and multimeric PSMA-targeting small molecule-thorium-227 conjugates for optimized efficacy and biodistribution in preclinical models. Eur J Nucl Med Mol Imaging 2024; 51:669-680. [PMID: 37882848 PMCID: PMC10796422 DOI: 10.1007/s00259-023-06474-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 10/15/2023] [Indexed: 10/27/2023]
Abstract
PURPOSE PSMA (prostate-specific membrane antigen) is highly expressed on prostate cancer (PrCa) cells and extensively used as a homing target for PrCa treatment. Most prominently, PSMA-targeting conjugate PSMA-617, carrying a DOTA chelator and labeled with therapeutic radionuclides like beta-emitting lutetium-177 or alpha-emitting actinium-225, has shown clinical activity in PrCa patients. We sought to develop PSMA-targeting small molecule (SMOL) conjugates that show high uptake in PSMA-expressing tumors and fast clearance, and can easily be labeled with the alpha emitter thorium-227 (half-life 18.7 days). METHODS A novel linker motif with improved competition against 3H-PSMA-617 on PSMA-expressing LNCaP cells was identified. A 2,3-hydroxypyridinone chelator modified with carboxyl groups (carboxy-HOPO) with increased hydrophilicity and robust labeling with thorium-227 was developed and allowed the synthesis of mono-, di-, tri-, and tetrameric conjugates. The resulting monomeric and multimeric PSMA SMOL-TTCs (targeted thorium conjugate) were evaluated for cellular binding, internalization, and antiproliferative activity. The in vivo antitumor efficacy of the PSMA SMOL-TTCs was determined in ST1273 and KUCaP-1 PrCa models in mice, and their biodistribution was assessed in cynomolgus monkeys, minipigs, and mice. RESULTS The monomeric and multimeric PSMA SMOL conjugates were readily labeled with thorium-227 at room temperature and possessed high stability and good binding, internalization, and antiproliferative activity in vitro. In vivo, the monomeric, dimeric, and trimeric PSMA SMOL-TTCs showed fast clearance, potent antitumor efficacy, and high uptake and retention in prostate tumors in mice. No major uptake or retention in other organs was observed beyond kidneys. Low uptake of free thorium-227 into bone confirmed high complex stability in vivo. Salivary gland uptake remained inconclusive as mini pigs were devalidated as a relevant model and imaging controls failed in cynomolgus monkeys. CONCLUSION Monomeric and multimeric PSMA SMOL-TTCs show high tumor uptake and fast clearance in preclinical models and warrant further therapeutic exploration.
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Affiliation(s)
- Niels Böhnke
- Pharmaceuticals, Bayer AG, 13342, Berlin, Germany
| | | | | | | | | | - Hans Briem
- Pharmaceuticals, Bayer AG, 13342, Berlin, Germany
| | - Arif Celik
- Pharmaceuticals, Bayer AG, 13342, Berlin, Germany
| | - Dominik Mumberg
- Pharmaceuticals, Bayer AG, 13342, Berlin, Germany
- Adcendo ApS, Copenhagen, Denmark
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Echavidre W, Fagret D, Faraggi M, Picco V, Montemagno C. Recent Pre-Clinical Advancements in Nuclear Medicine: Pioneering the Path to a Limitless Future. Cancers (Basel) 2023; 15:4839. [PMID: 37835533 PMCID: PMC10572076 DOI: 10.3390/cancers15194839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 09/14/2023] [Accepted: 09/18/2023] [Indexed: 10/15/2023] Open
Abstract
The theranostic approach in oncology holds significant importance in personalized medicine and stands as an exciting field of molecular medicine. Significant achievements have been made in this field in recent decades, particularly in treating neuroendocrine tumors using 177-Lu-radiolabeled somatostatin analogs and, more recently, in addressing prostate cancer through prostate-specific-membrane-antigen targeted radionuclide therapy. The promising clinical results obtained in these indications paved the way for the further development of this approach. With the continuous discovery of new molecular players in tumorigenesis, the development of novel radiopharmaceuticals, and the potential combination of theranostics agents with immunotherapy, nuclear medicine is poised for significant advancements. The strategy of theranostics in oncology can be categorized into (1) repurposing nuclear medicine agents for other indications, (2) improving existing radiopharmaceuticals, and (3) developing new theranostics agents for tumor-specific antigens. In this review, we provide an overview of theranostic development and shed light on its potential integration into combined treatment strategies.
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Affiliation(s)
- William Echavidre
- Biomedical Department, Centre Scientifique de Monaco, 98000 Monaco, Monaco; (W.E.); (V.P.)
| | - Daniel Fagret
- Laboratory of Bioclinical Radiopharmaceutics, Universite Grenoble Alpes, CHU Grenoble Alpes, Inserm, 38000 Grenoble, France;
| | - Marc Faraggi
- Nuclear Medicine Department, Centre Hospitalier Princesse Grace, 98000 Monaco, Monaco;
| | - Vincent Picco
- Biomedical Department, Centre Scientifique de Monaco, 98000 Monaco, Monaco; (W.E.); (V.P.)
| | - Christopher Montemagno
- Biomedical Department, Centre Scientifique de Monaco, 98000 Monaco, Monaco; (W.E.); (V.P.)
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Zitzmann-Kolbe S, Kristian A, Zopf D, Kamfenkel C, Politz O, Ellingsen C, Hilbig J, Juul MU, Fonslet J, Nielsen CH, Schatz CA, Bjerke RM, Cuthbertson AS, Mumberg D, Hagemann UB. A Targeted Thorium-227 Conjugate Demonstrates Efficacy in Preclinical Models of Acquired Drug Resistance and Combination Potential with Chemotherapeutics and Antiangiogenic Therapies. Mol Cancer Ther 2023; 22:1073-1086. [PMID: 37365121 PMCID: PMC10477831 DOI: 10.1158/1535-7163.mct-22-0808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 04/17/2023] [Accepted: 06/23/2023] [Indexed: 06/28/2023]
Abstract
Targeted alpha therapies (TAT) are an innovative class of therapies for cancer treatment. The unique mode-of-action of TATs is the induction of deleterious DNA double-strand breaks. Difficult-to-treat cancers, such as gynecologic cancers upregulating the chemoresistance P-glycoprotein (p-gp) and overexpressing the membrane protein mesothelin (MSLN), are promising targets for TATs. Here, based on the previous encouraging findings with monotherapy, we investigated the efficacy of the mesothelin-targeted thorium-227 conjugate (MSLN-TTC) both as monotherapy and in combination with chemotherapies and antiangiogenic compounds in ovarian and cervical cancer models expressing p-gp. MSLN-TTC monotherapy showed equal cytotoxicity in vitro in p-gp-positive and -negative cancer cells, while chemotherapeutics dramatically lost activity on p-gp-positive cancer cells. In vivo, MSLN-TTC exhibited dose-dependent tumor growth inhibition with treatment/control ratios of 0.03-0.44 in various xenograft models irrespective of p-gp expression status. Furthermore, MSLN-TTC was more efficacious in p-gp-expressing tumors than chemotherapeutics. In the MSLN-expressing ST206B ovarian cancer patient-derived xenograft model, MSLN-TTC accumulated specifically in the tumor, which combined with pegylated liposomal doxorubicin (Doxil), docetaxel, bevacizumab, or regorafenib treatment induced additive-to-synergistic antitumor efficacy and substantially increased response rates compared with respective monotherapies. The combination treatments were well tolerated and only transient decreases in white and red blood cells were observed. In summary, we demonstrate that MSLN-TTC treatment shows efficacy in p-gp-expressing models of chemoresistance and has combination potential with chemo- and antiangiogenic therapies.
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7
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Alati S, Singh R, Pomper MG, Rowe SP, Banerjee SR. Preclinical Development in Radiopharmaceutical Therapy for Prostate Cancer. Semin Nucl Med 2023; 53:663-686. [PMID: 37468417 DOI: 10.1053/j.semnuclmed.2023.06.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 06/19/2023] [Accepted: 06/21/2023] [Indexed: 07/21/2023]
Abstract
Prostate cancer is a leading cause of cancer death in men worldwide. Among the various treatment options, radiopharmaceutical therapy has shown notable success in metastatic, castration-resistant disease. Radiopharmaceutical therapy is a systemic approach that delivers cytotoxic radiation doses precisely to the malignant tumors and/or tumor microenvironment. Therapeutic radiopharmaceuticals are composed of a therapeutic radionuclide and a high-affinity, tumor-targeting carrier molecule. Therapeutic radionuclides used in preclinical prostate cancer studies are primarily α-, β--, or Auger-electron-emitting radiometals or radiohalogens. Monoclonal antibodies, antibody-derived fragments, peptides, and small molecules are frequently used as tumor-targeting molecules. Over the years, several important membrane-associated proteases and receptors have been identified, validated, and subsequently used for preclinical radiotherapeutic development for prostate cancer. Prostate-specific membrane antigen (PSMA) is the most well-studied prostate cancer-associated protease in preclinical literature. PSMA-targeting radiotherapeutic agents are being investigated using high-affinity antibody- and small-molecule-based agents for safety and efficacy. Early generations of such agents were developed simply by replacing radionuclides of the imaging agents with therapeutic ones. Later, extensive structure-activity relationship studies were conducted to address the safety and efficacy issues obtained from initial patient data. Recent regulatory approval of the 177Lu-labeled low-molecular-weight agent, 177Lu-PSMA-617, is a significant accomplishment. Current preclinical experiments are focused on the structural modification of 177Lu-PSMA-617 and relevant investigational agents to increase tumor targeting and reduce off-target binding and toxicity in healthy organs. While lutetium-177 (177Lu) remains the most widely used radionuclide, radiolabeled analogs with iodine-131 (128I), yttrium-90 (89Y), copper-67 (67Cu), and terbium-161 (161Tb) have been evaluated as potential alternatives in recent years. In addition, agents carrying the α-particle-emitting radiohalogen, astatine-211 (211At), or radiometals, actinium-225 (225Ac), lead-212 (212Pb), radium-223 (223Ra), and thorium-227 (227Th), have been increasingly investigated in preclinical research. Besides PSMA-based radiotherapeutics, other prominent prostate cancer-related proteases, for example, human kallikrein peptidases (HK2 and HK3), have been explored using monoclonal-antibody-(mAb)-based targeting platforms. Several promising mAbs targeting receptors overexpressed on the different stages of prostate cancer have also been developed for radiopharmaceutical therapy, for example, Delta-like ligand 3 (DLL-3), CD46, and CUB domain-containing protein 1 (CDCP1). Progress is also being made using peptide-based targeting platforms for the gastrin-releasing peptide receptor (GRPR), a well-established membrane-associated receptor expressed in localized and metastatic prostate cancers. Furthermore, mechanism-driven combination therapies appear to be a burgeoning area in the context of preclinical prostate cancer radiotherapeutics. Here, we review the current developments related to the preclinical radiopharmaceutical therapy of prostate cancer. These are summarized in two major topics: (1) therapeutic radionuclides and (2) tumor-targeting approaches using monoclonal antibodies, small molecules, and peptides.
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Affiliation(s)
- Suresh Alati
- Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, MD; Sidney Kimmel Comprehensive Cancer Center, Baltimore, MD
| | - Rajan Singh
- Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, MD; Sidney Kimmel Comprehensive Cancer Center, Baltimore, MD
| | - Martin G Pomper
- Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, MD; Sidney Kimmel Comprehensive Cancer Center, Baltimore, MD
| | - Steven P Rowe
- Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, MD; Sidney Kimmel Comprehensive Cancer Center, Baltimore, MD
| | - Sangeeta Ray Banerjee
- Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, MD; Sidney Kimmel Comprehensive Cancer Center, Baltimore, MD.
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Inderjeeth A, Iravani A, Subramaniam S, Conduit C, Sandhu S. Novel radionuclide therapy combinations in prostate cancer. Ther Adv Med Oncol 2023; 15:17588359231187202. [PMID: 37547444 PMCID: PMC10399256 DOI: 10.1177/17588359231187202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 06/21/2023] [Indexed: 08/08/2023] Open
Abstract
Prostate cancer remains the commonest cancer diagnosed in males and a leading cause of cancer-related death. Men with metastatic castration-resistant prostate cancer (mCRPC) who have progressed on chemotherapy and androgen receptor pathway inhibitors (ARPI) have limited treatment options, significant morbidity, and poor outcomes. Prostate-specific membrane antigen (PSMA)-directed radionuclide therapy (RNT) is emerging as an efficacious and well-tolerated therapy; however, disease progression is universal. Several ongoing RNT trials focus on combination strategies to improve efficacy and durability of treatment response, including combinations with ARPIs, chemotherapy, immunotherapy, and targeted therapies. Further, efforts are underway to expand the role of PSMA-directed RNT to earlier stages of disease including hormone-sensitive and localized prostate cancer. In this review, we discuss the rationale and ongoing RNT combination therapeutic trials in prostate cancer and summarize the efficacy and toxicity associated with RNT.
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Affiliation(s)
- Andrisha–Jade Inderjeeth
- Department of Medical Oncology, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia
- Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia
| | - Amir Iravani
- Department of Radiology, University of Washington, Seattle, WA, USA
| | - Shalini Subramaniam
- NHMRC Clinical Trials Centre, University of Sydney, Sydney, NSW, Australia
- Department of Medical Oncology, Bankstown-Lidcombe Hospital, Bankstown, NSW, Australia
| | - Ciara Conduit
- Department of Medical Oncology, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia
- Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia
- Sir Peter MacCallum Cancer Department of Oncology, University of Melbourne, Melbourne, VIC, Australia
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9
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Karlsson J, Hagemann UB, Cruciani V, Schatz CA, Grant D, Ellingsen C, Kristian A, Katoozi S, Mihaylova D, Uran SR, Suominen M, Bjerke RM, Ryan OB, Cuthbertson A. Efficacy of a HER2-Targeted Thorium-227 Conjugate in a HER2-Positive Breast Cancer Bone Metastasis Model. Cancers (Basel) 2023; 15:3419. [PMID: 37444529 DOI: 10.3390/cancers15133419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 06/16/2023] [Accepted: 06/28/2023] [Indexed: 07/15/2023] Open
Abstract
Human epidermal growth factor receptor 2 (HER2) is overexpressed in 15-30% of breast cancers but has low expression in normal tissue, making it attractive for targeted alpha therapy (TAT). HER2-positive breast cancer typically metastasizes to bone, resulting in incurable disease and significant morbidity and mortality. Therefore, new strategies for HER2-targeting therapy are needed. Here, we present the preclinical in vitro and in vivo characterization of the HER2-targeted thorium-227 conjugate (HER2-TTC) TAT in various HER2-positive cancer models. In vitro, HER2-TTC showed potent cytotoxicity in various HER2-expressing cancer cell lines and increased DNA double strand break formation and the induction of cell cycle arrest in BT-474 cells. In vivo, HER2-TTC demonstrated dose-dependent antitumor efficacy in subcutaneous xenograft models. Notably, HER2-TTC also inhibited intratibial tumor growth and tumor-induced abnormal bone formation in an intratibial BT-474 mouse model that mimics breast cancer metastasized to bone. Furthermore, a match in HER2 expression levels between primary breast tumor and matched bone metastases samples from breast cancer patients was observed. These results demonstrate proof-of-concept for TAT in the treatment of patients with HER2-positive breast cancer, including cases where the tumor has metastasized to bone.
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Affiliation(s)
- Jenny Karlsson
- Targeted Radiopharmaceuticals, Bayer AS, 0283 Oslo, Norway
| | | | | | | | - Derek Grant
- Targeted Radiopharmaceuticals, Bayer AS, 0283 Oslo, Norway
| | | | | | - Shirin Katoozi
- Targeted Radiopharmaceuticals, Bayer AS, 0283 Oslo, Norway
| | | | - Steinar R Uran
- Targeted Radiopharmaceuticals, Bayer AS, 0283 Oslo, Norway
| | | | - Roger M Bjerke
- Targeted Radiopharmaceuticals, Bayer AS, 0283 Oslo, Norway
| | - Olav B Ryan
- Targeted Radiopharmaceuticals, Bayer AS, 0283 Oslo, Norway
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Deshayes E, Fersing C, Thibault C, Roumiguie M, Pourquier P, Houédé N. Innovation in Radionuclide Therapy for the Treatment of Prostate Cancers: Radiochemical Perspective and Recent Therapeutic Practices. Cancers (Basel) 2023; 15:3133. [PMID: 37370743 DOI: 10.3390/cancers15123133] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 05/31/2023] [Accepted: 06/07/2023] [Indexed: 06/29/2023] Open
Abstract
Prostate cancer represents the second cause of death by cancer in males in western countries. While early-stage diseases are accessible to surgery and/or external radiotherapy, advanced metastatic prostate cancers are primarily treated with androgen deprivation therapy, to which new generation androgen receptor antagonists or taxane-based chemotherapies are added in the case of tumor relapse. Nevertheless, patients become invariably resistant to castration with a median survival that rarely exceeds 3 years. This fostered the search for alternative strategies, independent of the androgen receptor signaling pathway. In this line, radionuclide therapies may represent an interesting option as they could target either the microenvironment of sclerotic bone metastases with the use of radiopharmaceuticals containing samarium-153, strontium-89 or radium-223 or tumor cells expressing the prostate-specific membrane antigen (PSMA), a protein found at the surface of prostate cancer cells. This review gives highlights the chemical properties of radioligands targeting prostate cancer cells and recapitulates the clinical trials evaluating the efficacy of radionuclide therapies, alone or in combination with other approved treatments, in patients with castration-resistant prostate tumors. It discusses some of the encouraging results obtained, especially the benefit on overall survival that was reported with [177Lu]-PSMA-617. It also addresses the specific requirements for the use of this particular class of drugs, both in terms of medical staff coordination and adapted infrastructures for efficient radioprotection.
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Affiliation(s)
- Emmanuel Deshayes
- INSERM U1194, Montpellier Cancer Research Institute, University of Montpellier, 34298 Montpellier, France
- Department of Nuclear Medicine, Institute du Cancer de Montpellier (ICM), 34298 Montpellier, France
| | - Cyril Fersing
- Department of Nuclear Medicine, Institute du Cancer de Montpellier (ICM), 34298 Montpellier, France
- IBMM, University Montpellier, CNRS, ENSCM, 34293 Montpellier, France
| | - Constance Thibault
- Department of Medical Oncology, Hôpital Européen Georges Pompidou, Institut du Cancer Paris CARPEM, AP-HP Centre, 75015 Paris, France
| | - Mathieu Roumiguie
- Urology Department, Andrology and Renal Transplantation, CHU Rangueil, 31059 Toulouse, France
| | - Philippe Pourquier
- INSERM U1194, Montpellier Cancer Research Institute, University of Montpellier, 34298 Montpellier, France
| | - Nadine Houédé
- INSERM U1194, Montpellier Cancer Research Institute, University of Montpellier, 34298 Montpellier, France
- Medical Oncology Department, Institute de Cancérologie du Gard-CHU Caremeau, 30009 Nîmes, France
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11
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Karlsson J, Schatz CA, Wengner AM, Hammer S, Scholz A, Cuthbertson A, Wagner V, Hennekes H, Jardine V, Hagemann UB. Targeted thorium-227 conjugates as treatment options in oncology. Front Med (Lausanne) 2023; 9:1071086. [PMID: 36726355 PMCID: PMC9885765 DOI: 10.3389/fmed.2022.1071086] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Accepted: 12/15/2022] [Indexed: 01/10/2023] Open
Abstract
Targeted alpha therapy (TAT) is a promising approach for addressing unmet needs in oncology. Inherent properties make α-emitting radionuclides well suited to cancer therapy, including high linear energy transfer (LET), penetration range of 2-10 cell layers, induction of complex double-stranded DNA breaks, and immune-stimulatory effects. Several alpha radionuclides, including radium-223 (223Ra), actinium-225 (225Ac), and thorium-227 (227Th), have been investigated. Conjugation of tumor targeting modalities, such as antibodies and small molecules, with a chelator moiety and subsequent radiolabeling with α-emitters enables specific delivery of cytotoxic payloads to different tumor types. 223Ra dichloride, approved for the treatment of patients with metastatic castration-resistant prostate cancer (mCRPC) with bone-metastatic disease and no visceral metastasis, is the only approved and commercialized alpha therapy. However, 223Ra dichloride cannot currently be complexed to targeting moieties. In contrast to 223Ra, 227Th may be readily chelated, which allows radiolabeling of tumor targeting moieties to produce targeted thorium conjugates (TTCs), facilitating delivery to a broad range of tumors. TTCs have shown promise in pre-clinical studies across a range of tumor-cell expressing antigens. A clinical study in hematological malignancy targeting CD22 has demonstrated early signs of activity. Furthermore, pre-clinical studies show additive or synergistic effects when TTCs are combined with established anti-cancer therapies, for example androgen receptor inhibitors (ARI), DNA damage response inhibitors such as poly (ADP)-ribose polymerase inhibitors or ataxia telangiectasia and Rad3-related kinase inhibitors, as well as immune checkpoint inhibitors.
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Sheehan B, Neeb A, Buroni L, Paschalis A, Riisnaes R, Gurel B, Gil V, Miranda S, Crespo M, Guo C, Jiménez Vacas J, Figueiredo I, Ferreira A, Welti J, Yuan W, Carreira S, Sharp A, de Bono J. Prostate-Specific Membrane Antigen Expression and Response to DNA Damaging Agents in Prostate Cancer. Clin Cancer Res 2022; 28:3104-3115. [PMID: 35552383 PMCID: PMC9365343 DOI: 10.1158/1078-0432.ccr-21-4531] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 03/15/2022] [Accepted: 05/09/2022] [Indexed: 01/07/2023]
Abstract
PURPOSE Prostate-specific membrane antigen (PSMA) targeting therapies such as Lutetium-177 (177Lu)-PSMA-617 are affecting outcomes from metastatic castration-resistant prostate cancer (mCRPC). However, a significant subset of patients have prostate cancer cells lacking PSMA expression, raising concerns about treatment resistance attributable at least in part to heterogeneous PSMA expression. We have previously demonstrated an association between high PSMA expression and DNA damage repair defects in mCRPC biopsies and therefore hypothesized that DNA damage upregulates PSMA expression. EXPERIMENTAL DESIGN To test this relationship between PSMA and DNA damage we conducted a screen of 147 anticancer agents (NCI/NIH FDA-approved anticancer "Oncology Set") and treated tumor cells with repeated ionizing irradiation. RESULTS The topoisomerase-2 inhibitors, daunorubicin and mitoxantrone, were identified from the screen to upregulate PSMA protein expression in castration-resistant LNCaP95 cells; this result was validated in vitro in LNCaP, LNCaP95, and 22Rv1 cell lines and in vivo using an mCRPC patient-derived xenograft model CP286 identified to have heterogeneous PSMA expression. As double-strand DNA break induction by topoisomerase-2 inhibitors upregulated PSMA, we next studied the impact of ionizing radiation on PSMA expression; this also upregulated PSMA protein expression in a dose-dependent fashion. CONCLUSIONS The results presented herein are the first, to our knowledge, to demonstrate that PSMA is upregulated in response to double-strand DNA damage by anticancer treatment. These data support the study of rational combinations that maximize the antitumor activity of PSMA-targeted therapeutic strategies by upregulating PSMA.
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Affiliation(s)
| | - Antje Neeb
- The Institute of Cancer Research, London, UK
| | | | - Alec Paschalis
- The Institute of Cancer Research, London, UK
- The Royal Marsden NHS Foundation Trust, Sutton, UK
| | | | - Bora Gurel
- The Institute of Cancer Research, London, UK
| | | | | | | | - Christina Guo
- The Institute of Cancer Research, London, UK
- The Royal Marsden NHS Foundation Trust, Sutton, UK
| | | | | | | | - Jon Welti
- The Institute of Cancer Research, London, UK
| | - Wei Yuan
- The Institute of Cancer Research, London, UK
| | | | - Adam Sharp
- The Institute of Cancer Research, London, UK
- The Royal Marsden NHS Foundation Trust, Sutton, UK
| | - Johann de Bono
- The Institute of Cancer Research, London, UK
- The Royal Marsden NHS Foundation Trust, Sutton, UK
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Radiobiology of Targeted Alpha Therapy. Nucl Med Mol Imaging 2022. [DOI: 10.1016/b978-0-12-822960-6.00093-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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