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Trencsényi G, Csikos C, Képes Z. Targeted Radium Alpha Therapy in the Era of Nanomedicine: In Vivo Results. Int J Mol Sci 2024; 25:664. [PMID: 38203834 PMCID: PMC10779852 DOI: 10.3390/ijms25010664] [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: 11/01/2023] [Revised: 12/20/2023] [Accepted: 12/27/2023] [Indexed: 01/12/2024] Open
Abstract
Targeted alpha-particle therapy using radionuclides with alpha emission is a rapidly developing area in modern cancer treatment. To selectively deliver alpha-emitting isotopes to tumors, targeting vectors, including monoclonal antibodies, peptides, small molecule inhibitors, or other biomolecules, are attached to them, which ensures specific binding to tumor-related antigens and cell surface receptors. Although earlier studies have already demonstrated the anti-tumor potential of alpha-emitting radium (Ra) isotopes-Radium-223 and Radium-224 (223/224Ra)-in the treatment of skeletal metastases, their inability to complex with target-specific moieties hindered application beyond bone targeting. To exploit the therapeutic gains of Ra across a wider spectrum of cancers, nanoparticles have recently been embraced as carriers to ensure the linkage of 223/224Ra to target-affine vectors. Exemplified by prior findings, Ra was successfully bound to several nano/microparticles, including lanthanum phosphate, nanozeolites, barium sulfate, hydroxyapatite, calcium carbonate, gypsum, celestine, or liposomes. Despite the lengthened tumor retention and the related improvement in the radiotherapeutic effect of 223/224Ra coupled to nanoparticles, the in vivo assessment of the radiolabeled nanoprobes is a prerequisite prior to clinical usage. For this purpose, experimental xenotransplant models of different cancers provide a well-suited scenario. Herein, we summarize the latest achievements with 223/224Ra-doped nanoparticles and related advances in targeted alpha radiotherapy.
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Affiliation(s)
- György Trencsényi
- Division of Nuclear Medicine and Translational Imaging, Department of Medical Imaging, Faculty of Medicine, University of Debrecen, Nagyerdei St. 98, H-4032 Debrecen, Hungary; (G.T.); (C.C.)
| | - Csaba Csikos
- Division of Nuclear Medicine and Translational Imaging, Department of Medical Imaging, Faculty of Medicine, University of Debrecen, Nagyerdei St. 98, H-4032 Debrecen, Hungary; (G.T.); (C.C.)
- Gyula Petrányi Doctoral School of Clinical Immunology and Allergology, Faculty of Medicine, University of Debrecen, Nagyerdei St. 98, H-4032 Debrecen, Hungary
| | - Zita Képes
- Division of Nuclear Medicine and Translational Imaging, Department of Medical Imaging, Faculty of Medicine, University of Debrecen, Nagyerdei St. 98, H-4032 Debrecen, Hungary; (G.T.); (C.C.)
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Hoseini-Ghahfarokhi M, Kamio Y, Mondor J, Jabbari K, Carrier JF. Development of a stand-alone precalculated Monte Carlo code to calculate the dose by alpha and beta emitters from the Ra-224 decay chain. Med Phys 2023; 50:5176-5188. [PMID: 37161766 DOI: 10.1002/mp.16446] [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: 10/06/2022] [Revised: 04/05/2023] [Accepted: 04/15/2023] [Indexed: 05/11/2023] Open
Abstract
BACKGROUND Recent developments in alpha and beta emitting radionuclide therapy highlight the importance of developing efficient methods for patient-specific dosimetry. Traditional tabulated methods such as Medical Internal Radiation Dose (MIRD) estimate the dose at the organ level while more recent numerical methods based on Monte Carlo (MC) simulations are able to calculate dose at the voxel level. A precalculated MC (PMC) approach was developed in this work as an alternative to time-consuming fully simulated MC. Once the spatial distribution of alpha and beta emitters is determined using imaging and/or numerical methods, the PMC code can be used to achieve an accurate voxelized 3D distribution of the deposited energy without relying on full MC calculations. PURPOSE To implement the PMC method to calculate energy deposited by alpha and beta particles emitted from the Ra-224 decay chain. METHODS The GEANT4 (version 10.7) MC toolkit was used to generate databases of precalculated tracks to be integrated in the PMC code as well as to benchmark its output. In this regard, energy spectra of alpha and beta particles emitted by the Ra-224 decay chain were generated using GAMOS (version 6.2.0) and imported into GEANT4 macro files. Either alpha or beta emitting sources were defined at the center of a homogeneous phantom filled with various materials such as soft tissue, bone, and lung where particles were emitted either mono-directionally (for database generation) or isotropically (for benchmarking). Two heterogeneous phantoms were used to demonstrate PMC code compatibility with boundary crossing events. Each precalculated database was generated step-by-step by storing particle track information from GEANT4 simulations followed by its integration in a PMC code developed in MATLAB. For a user-defined number of histories, one of the tracks in a given database was selected randomly and rotated randomly to reflect an isotropic emission. Afterward, deposited energy was divided between voxels based on step length in each voxel using a ray-tracing approach. The radial distribution of deposited energy was benchmarked against fully simulated MC calculations using GEANT4. The effect of the GEANT4 parameter StepMax on the accuracy and speed of the code was also investigated. RESULTS In the case of alpha decay, primary alpha particles show the highest contribution (>99%) in deposited energy compared to their secondary particles. In most cases, protons act as the main secondary particles in the deposition of energy. However, for a lung phantom, using a range cutoff parameter of 10 µm on primary alpha particles yields a higher contribution of secondary electrons than protons. Differences between deposited energy calculated by PMC and fully simulated MC are within 2% for all alpha and beta emitters in homogeneous and heterogeneous phantoms. Additionally, statistical uncertainties are less than 1% for voxels with doses higher than 5% of the maximum dose. Moreover, optimization of the parameter StepMax is necessary to achieve the best tradeoff between code accuracy and speed. CONCLUSIONS The PMC code shows good performance for dose calculations deposited by alpha and beta emitters. As a stand-alone algorithm, it is suitable to be integrated into clinical treatment planning systems.
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Affiliation(s)
- Mojtaba Hoseini-Ghahfarokhi
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montréal, Quebec, Canada
- Département de Physique, Université de Montréal, Montréal, Quebec, Canada
| | - Yuji Kamio
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montréal, Quebec, Canada
- Département de Pharmacologie et Physiologie, Université de Montréal, Montréal, Quebec, Canada
- Département de Radio-oncologie, Centre Hospitalier de l'Université de Montréal (CHUM), Montréal, Quebec, Canada
| | - Julien Mondor
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montréal, Quebec, Canada
- Département de Physique, Université de Montréal, Montréal, Quebec, Canada
| | - Keyvan Jabbari
- Department of Radiation Oncology, Champlain Valley Physicians Hospital, Plattsburgh, New York, USA
| | - Jean-François Carrier
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montréal, Quebec, Canada
- Département de Physique, Université de Montréal, Montréal, Quebec, Canada
- Département de Radio-oncologie, Centre Hospitalier de l'Université de Montréal (CHUM), Montréal, Quebec, Canada
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Grønningsæter SR, Blakkisrud J, Selboe S, Revheim ME, Bruland ØS, Bønsdorff TB, Larsen SG, Stokke C. Radiation safety considerations for the use of radium-224-calciumcarbonate-microparticles in patients with peritoneal metastasis. Front Med (Lausanne) 2023; 10:1058914. [PMID: 36844217 PMCID: PMC9945525 DOI: 10.3389/fmed.2023.1058914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 01/18/2023] [Indexed: 02/10/2023] Open
Abstract
Aim Two ongoing phase I studies are investigating the use of radium-224 adsorbed to calcium carbonate micro particles (224Ra-CaCO3-MP) to treat peritoneal metastasis originating from colorectal or ovarian cancer. The aim of this work was to study the level of radiation exposure from the patients to workers at the hospital, carers and members of the public. Method Six patients from the phase 1 trial in patients with colorectal cancer were included in this study. Two days after cytoreductive surgery, they were injected with 7 MBq of 224Ra-CaCO3-MP. At approximately 3, 24 and 120 h after injection, the patients underwent measurements with an ionization chamber and a scintillator-based iodide detector, and whole body gamma camera imaging. The patient was modelled as a planar source to calculate dose rate as a function of distance. Scenarios varying in duration and distance from the patient were created to estimate the potential effective doses from external exposure. Urine and blood samples were collected at approximately 3, 6, 24, 48 and 120 h after injection of 224Ra-CaCO3-MP, to estimate the activity concentration of 224Ra and 212Pb. Results The patients' median effective whole-body half-life of 224Ra-CaCO3-MP ranged from 2.6 to 3.5 days, with a mean value of 3.0 days. In the scenarios with exposure at the hospital (first 8 days), sporadic patient contact resulted in a range of 3.9-6.8 μSv per patient, and daily contact resulted in 4.3-31.3 μSv depending on the scenario. After discharge from the hospital, at day 8, the highest effective dose was received by those with close daily contact; 18.7-83.0 μSv. The highest activity concentrations of 224Ra and 212Pb in urine and blood were found within 6 h, with maximum values of 70 Bq/g for 224Ra and 628 Bq/g for 212Pb. Conclusion The number of patients treated with 224Ra-CaCO3-MP that a single hospital worker - involved in extensive care - can receive per year, before effective doses of 6 mSv from external exposure is exceeded, is in the order of 200-400. Members of the public and family members are expected to receive well below 0.25 mSv, and therefore, no restrictions to reduce external exposure should be required.
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Affiliation(s)
- Simen Rykkje Grønningsæter
- Division of Radiology and Nuclear Medicine, Oslo University Hospital, Oslo, Norway,*Correspondence: Simen Rykkje Grønningsæter, ✉
| | - Johan Blakkisrud
- Division of Radiology and Nuclear Medicine, Oslo University Hospital, Oslo, Norway
| | - Silje Selboe
- Division of Radiology and Nuclear Medicine, Oslo University Hospital, Oslo, Norway
| | - Mona-Elisabeth Revheim
- Division of Radiology and Nuclear Medicine, Oslo University Hospital, Oslo, Norway,Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Øyvind Sverre Bruland
- Department of Oncology, Oslo University Hospital, Oslo, Norway,Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | | | - Stein Gunnar Larsen
- Department of Gastroenterological Surgery, Oslo University Hospital, Oslo, Norway
| | - Caroline Stokke
- Division of Radiology and Nuclear Medicine, Oslo University Hospital, Oslo, Norway,Department of Physics, University of Oslo, Oslo, Norway
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Juzeniene A, Stenberg VY, Bruland ØS, Revheim ME, Larsen RH. Dual targeting with 224Ra/ 212Pb-conjugates for targeted alpha therapy of disseminated cancers: A conceptual approach. Front Med (Lausanne) 2023; 9:1051825. [PMID: 36733936 PMCID: PMC9887039 DOI: 10.3389/fmed.2022.1051825] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Accepted: 12/05/2022] [Indexed: 01/18/2023] Open
Abstract
Metastases are the primary cause of death among cancer patients and efficacious new treatments are sorely needed. Targeted alpha-emitting radiopharmaceuticals that are highly cytotoxic may fulfill this critical need. The focus of this paper is to describe and explore a novel technology that may improve the therapeutic effect of targeted alpha therapy by combining two radionuclides from the same decay chain in the same solution. We hypothesize that the dual targeting solution containing bone-seeking 224Ra and cell-directed complexes of progeny 212Pb is a promising approach to treat metastatic cancers with bone and soft tissue lesions as well as skeletal metastases of mixed lytic/osteoblastic nature. A novel liquid 224Ra/212Pb-generator for rapid preparation of a dual targeting solution is described. Cancer cell targeting monoclonal antibodies, their fragments, synthetic proteins or peptides can all be radiolabeled with 212Pb in the 224Ra-solution in transient equilibrium with daughter nuclides. Thus, 224Ra targets stromal elements in sclerotic bone metastases and 212Pb-chelated-conjugate targets tumor cells of metastatic prostate cancer or osteosarcoma. The dual targeting solution may also be explored to treat metastatic breast cancer or multiple myeloma after manipulation of bone metastases to a more osteoblastic phenotype by the use of bisphosphonates, denosumab, bortezomib or hormone therapy prior to treatment. This may improve targeting of bone-seeking 224Ra and render an augmented radiation dose deposited within metastases. Our preliminary preclinical studies provide conceptual evidence that the dual 224Ra-solution with bone or tumor-targeted delivery of 212Pb has potential to inhibit cancer metastases without significant toxicity. In some settings, the use of a booster dose of purified 212Pb-conjugate alone could be required to elevate the effect of this tumor cell directed component, if needed, e.g., in a fractionated treatment regimen, where the dual targeting solution will act as maintenance treatment.
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Affiliation(s)
- Asta Juzeniene
- Department of Radiation Biology, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway
- Department of Physics, University of Oslo, Oslo, Norway
| | - Vilde Yuli Stenberg
- Department of Radiation Biology, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway
- Institute for Clinical Medicine, University of Oslo, Oslo, Norway
- ARTBIO AS, Oslo, Norway
| | - Øyvind Sverre Bruland
- Institute for Clinical Medicine, University of Oslo, Oslo, Norway
- Department of Oncology, The Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway
| | - Mona-Elisabeth Revheim
- Institute for Clinical Medicine, University of Oslo, Oslo, Norway
- Division of Radiology and Nuclear Medicine, Oslo University Hospital, Oslo, Norway
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Lassmann M, Eberlein U. Comparing absorbed doses and radiation risk of the α-emitting bone-seekers [ 223Ra]RaCl 2 and [ 224Ra]RaCl 2. Front Med (Lausanne) 2023; 9:1057373. [PMID: 36687439 PMCID: PMC9847387 DOI: 10.3389/fmed.2022.1057373] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 12/05/2022] [Indexed: 01/05/2023] Open
Abstract
[223Ra]RaCl2 and [224Ra]RaCl2 are bone seekers, emitting high LET, and short range (< 100 μm) alpha-particles. Both radionuclides show similar decay properties; the total alpha energies are comparable (223Ra: ≈28 MeV, 224Ra: ≈26 MeV). [224Ra]RaCl2 has been used from the mid-1940s until 1990 for treating different bone and joint diseases with activities of up to approximately 50 MBq [224Ra]RaCl2. In 2013 [223Ra]RaCl2 obtained marketing authorization by the FDA and by the European Union for the treatment of metastatic prostate cancer with an activity to administer of 0.055 MBq per kg body weight for six cycles. For intravenous injections in humans a model calculation using the biokinetic model of ICRP67 shows a ratio of organ absorbed dose coefficients (224Ra:223Ra) between 0.37 (liver) and 0.97 except for the kidneys (2.27) and blood (1.57). For the red marrow as primary organ-at-risk, the ratio is 0.57. The differences are mainly caused be the differing half-lives of the decay products of both radium isotopes. Both radionuclides show comparable DNA damage patterns in peripheral blood mononuclear cells after internal ex-vivo irradiation. Data on the long-term radiation-associated side effects are only available for treatment with [224Ra]RaCl2. Two epidemiological studies followed two patient groups treated with [224Ra]RaCl2 for more than 25 years. One of them was the "Spiess study", a cohort of 899 juvenile patients who received several injections of [224Ra]RaCl2 with a mean specific activity of 0.66 MBq/kg. Another patient group of ankylosing spondylitis patients was treated with 10 repeated intravenous injections of [224Ra]RaCl2, 1 MBq each, 1 week apart. In total 1,471 of these patients were followed-up in the "Wick study". In both studies, an increased cancer mortality by leukemia and solid cancers was observed. Similar considerations on long-term effects likely apply to [223Ra]RaCl2 as well since the biokinetics are similar and the absorbed doses in the same range. However, this increased risk will most likely not be observed due to the much shorter life expectancy of prostate cancer patients treated with [223Ra]RaCl2.
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A Novel Single-Step-Labeled 212Pb-CaCO 3 Microparticle for Internal Alpha Therapy: Preparation, Stability, and Preclinical Data from Mice. MATERIALS 2021; 14:ma14237130. [PMID: 34885283 PMCID: PMC8658347 DOI: 10.3390/ma14237130] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 11/19/2021] [Accepted: 11/19/2021] [Indexed: 02/06/2023]
Abstract
Lead-212 is recognized as a promising radionuclide for targeted alpha therapy for tumors. Many studies of 212Pb-labeling of various biomolecules through bifunctional chelators have been conducted. Another approach to exploiting the cytotoxic effect is coupling the radionuclide to a microparticle acting as a carrier vehicle, which could be used for treating disseminated cancers in body cavities. Calcium carbonate may represent a suitable material, as it is biocompatible, biodegradable, and easy to synthesize. In this work, we explored 212Pb-labeling of various CaCO3 microparticles and developed a protocol that can be straightforwardly implemented by clinicians. Vaterite microparticles stabilized by pamidronate were effective as 212Pb carriers; labeling yields of ≥98% were achieved, and 212Pb was strongly retained by the particles in an in vitro stability assessment. Moreover, the amounts of 212Pb reaching the kidneys, liver, spleen, and skeleton of mice following intraperitoneal (i.p.) administration were very low compared to i.p. injection of unbound 212Pb2+, indicating that CaCO3-bound 212Pb exhibited stability when administered intraperitoneally. Therapeutic efficacy was observed in a model of i.p. ovarian cancer for all the tested doses, ranging from 63 to 430 kBq per mouse. Lead-212-labeled CaCO3 microparticles represent a promising candidate for treating intracavitary cancers.
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Improved Formulation of 224Ra-Labeled Calcium Carbonate Microparticles by Surface Layer Encapsulation and Addition of EDTMP. Pharmaceutics 2021; 13:pharmaceutics13050634. [PMID: 33946852 PMCID: PMC8145685 DOI: 10.3390/pharmaceutics13050634] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 04/22/2021] [Accepted: 04/27/2021] [Indexed: 01/01/2023] Open
Abstract
Radium-224-labeled CaCO3 microparticles have been developed to treat peritoneal carcinomatosis. The microparticles function as carriers of 224Ra, facilitating intraperitoneal retention of the alpha-emitting radionuclide. It was necessary to control the size of microparticles in suspension over time and introduce a sterilization process for the clinical use of the radiopharmaceutical. Ethylenediamine tetra(methylene phosphonic acid) (EDTMP) was investigated as a stabilizing additive. The possibility of encapsulating the radiolabeled microparticles with an outer surface layer of CaCO3 for the improved retention of radioactivity by the carrier was studied. This work evaluated these steps of optimization and their effect on radiochemical purity, the biodistribution of radionuclides, and therapeutic efficacy. An EDTMP concentration of >1% (w/w) relative to CaCO3 stabilized the particle size for at least one week. Without EDTMP, the median particle size increased from ~5 µm to ~25 µm immediately after sterilization by autoclaving, and the larger microparticles sedimented rapidly in suspension. The percentage of adsorbed 224Ra progeny 212Pb increased from 56% to 94% at 2.4-2.5% (w/w) EDTMP when the 224Ra-labeled microparticles were layer-encapsulated. The improved formulation also resulted in a suitable biodistribution of radionuclides in mice, as well as a survival benefit for mice with intraperitoneal ovarian or colorectal tumors.
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