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Heger G, Dumančić M, Luz I, Vatarescu M, Weizman N, Miller BW, Cooks T, Arazi L. First measurements of radon-220 diffusion in mice tumors, towards treatment planning in diffusing alpha-emitters radiation therapy. Med Phys 2024; 51:5045-5058. [PMID: 38507254 DOI: 10.1002/mp.17020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 01/22/2024] [Accepted: 02/21/2024] [Indexed: 03/22/2024] Open
Abstract
BACKGROUND Diffusing alpha-emitters radiation therapy ("Alpha-DaRT") is a new method for treating solid tumors with alpha particles, relying on the release of the short-lived alpha-emitting daughter atoms of radium-224 from interstitial sources inserted into the tumor. Alpha-DaRT tumor dosimetry is governed by the spread of radium's progeny around the source, as described by an approximate framework called the "diffusion-leakage model". The most important model parameters are the diffusion lengths of radon-220 and lead-212, and their estimation is therefore essential for treatment planning. PURPOSE Previous works have provided initial estimates for the dominant diffusion length, by measuring the activity spread inside mice-borne tumors several days after the insertion of an Alpha-DaRT source. The measurements, taken when lead-212 was in secular equilibrium with radium-224, were interpreted as representing the lead-212 diffusion length. The aim of this work is to provide first experimental estimates for the diffusion length of radon-220, using a new methodology. METHODS The diffusion length of radon-220 was estimated from autoradiography measurements of histological sections taken from 24 mice-borne subcutaneous tumors of five different types. Unlike previous studies, the source dwell time inside the tumor was limited to 30 min, to prevent the buildup of lead-212. To investigate the contribution of potential non-diffusive processes, experiments were done in two sets: fourteen in vivo tumors, where during the treatment the tumors were still carried by the mice with active blood supply, and 10 ex-vivo tumors, where the tumors were excised before source insertion and kept in a medium at37 ∘ C $37^\circ {\text{C}}$ with the source inside. RESULTS The measured diffusion lengths of radon-220, extracted by fitting the recorded activity pattern up to 1.5 mm from the source, lie in the range0.25 - 0.6 mm ${0.25-0.6}\nobreakspace {\text{mm}}$ , with no significant difference between the average values measured in in-vivo and ex-vivo tumors:L R n i n - v i v o = 0.40 ± 0.08 mm $L_{Rn}^{in-vivo}=0.40{\pm }0.08\nobreakspace {\text{mm}}$ versusL R n e x - v i v o = 0.39 ± 0.07 mm $L_{Rn}^{ex-vivo}=0.39{\pm }0.07\nobreakspace {\text{mm}}$ . However, in-vivo tumors display an enhanced spread of activity 2-3 mm away from the source. This effect is not explained by the current model and is much less pronounced in ex-vivo tumors. CONCLUSIONS The average measured radon-220 diffusion lengths in both in-vivo and ex-vivo tumors are consistent with published data on the diffusion length of radon in water and lie close to the upper limit of the previously estimated range of0.2 - 0.4 mm $0.2-0.4\nobreakspace {\text{mm}}$ . The observation that close to the source there is no apparent difference between in-vivo and ex-vivo tumors, and the good agreement with the theoretical model in this region suggest that the spread of radon-220 is predominantly diffusive in this region. The departure from the model prediction in in-vivo tumors at large radial distances may hint at potential vascular contribution, which will be the subject of future works.
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Affiliation(s)
- Guy Heger
- Unit of Nuclear Engineering, Faculty of Engineering Sciences, Ben-Gurion University of the Negev, Beersheba, Israel
| | - Mirta Dumančić
- Unit of Nuclear Engineering, Faculty of Engineering Sciences, Ben-Gurion University of the Negev, Beersheba, Israel
- Now at Gerald Bronfman Department of Oncology, Faculty of Medicine and Health Sciences, McGill University, Montreal, Quebec, Canada
| | - Ishai Luz
- The Shraga Segal Department of Microbiology, Immunology, and Genetics, Ben-Gurion University of the Negev, Beersheba, Israel
| | - Maayan Vatarescu
- The Shraga Segal Department of Microbiology, Immunology, and Genetics, Ben-Gurion University of the Negev, Beersheba, Israel
| | - Noam Weizman
- Unit of Nuclear Engineering, Faculty of Engineering Sciences, Ben-Gurion University of the Negev, Beersheba, Israel
- Oncology Department, Radiation Therapy Unit, Hadassah - Hebrew University Medical Center, Jerusalem, Israel
| | - Brian W Miller
- College of Medicine, Department of Radiation Oncology, Department of Medical Imaging, The University of Arizona, Tucson, Arizona, USA
| | - Tomer Cooks
- The Shraga Segal Department of Microbiology, Immunology, and Genetics, Ben-Gurion University of the Negev, Beersheba, Israel
| | - Lior Arazi
- Unit of Nuclear Engineering, Faculty of Engineering Sciences, Ben-Gurion University of the Negev, Beersheba, Israel
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Popovtzer A, Mizrachi A, D’Andrea MA, VanderWalde NA, Kurman N, Rosenfeld E, Ben-Hur R, Bellia SR, Feliciani G, Silvern D, Sarnelli A, Ballo MT, Patra P, Cohen GN, Damato AL, Shkedy Y, Den RB, Barker CA, Charas T, Hirshoren N. Extended Follow-Up Outcomes from Pooled Prospective Studies Evaluating Efficacy of Interstitial Alpha Radionuclide Treatment for Skin and Head and Neck Cancers. Cancers (Basel) 2024; 16:2312. [PMID: 39001374 PMCID: PMC11240433 DOI: 10.3390/cancers16132312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2024] [Revised: 06/02/2024] [Accepted: 06/06/2024] [Indexed: 07/16/2024] Open
Abstract
The initial favorable efficacy and safety profile for Alpha DaRT have been demonstrated (NCT04377360); however, the longer-term safety and durability of the treatment are unknown. This pooled analysis of four prospective trials evaluated the long-term safety and efficacy of Alpha DaRT for the treatment of head and neck or skin tumors. A total of 81 lesions in 71 patients were treated across six international institutions, with a median follow-up of 14.1 months (range: 2-51 months). Alpha DaRT sources were delivered via a percutaneous interstitial technique and placed to irradiate the tumor volume with the margin. The sources were removed two to three weeks following implantation. A complete response was observed in 89% of treated lesions (n = 72) and a partial response in 10% (n = 8). The two-year actuarial local recurrence-free survival was 77% [95% CI 63-87]. Variables, including recurrent versus non-recurrent lesions, baseline tumor size, or histology, did not impact long-term outcomes. Twenty-seven percent of patients developed related acute grade 2 or higher toxicities, which resolved with conservative measures. No grade 2 or higher late toxicities were observed. These data support the favorable safety profile of Alpha DaRT, which is currently being explored in a pivotal US trial.
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Affiliation(s)
| | - Aviram Mizrachi
- Rabin Medical Center, Derech Ze’ev Jabotinsky St., 39, Petah Tikva 4941492, Israel
| | - Mark A. D’Andrea
- University Cancer Centers, 12811 Beamer Rd, Houston, TX 77089, USA
| | | | - Noga Kurman
- Rabin Medical Center, Derech Ze’ev Jabotinsky St., 39, Petah Tikva 4941492, Israel
| | - Eli Rosenfeld
- Rabin Medical Center, Derech Ze’ev Jabotinsky St., 39, Petah Tikva 4941492, Israel
| | - Ran Ben-Hur
- Rabin Medical Center, Derech Ze’ev Jabotinsky St., 39, Petah Tikva 4941492, Israel
| | | | - Giacomo Feliciani
- IRCCS Istituto Romagnolo per lo Studio dei Tumori (IRST) “Dino Amadori”, 47014 Meldola, Italy
| | - David Silvern
- Rabin Medical Center, Derech Ze’ev Jabotinsky St., 39, Petah Tikva 4941492, Israel
| | - Anna Sarnelli
- IRCCS Istituto Romagnolo per lo Studio dei Tumori (IRST) “Dino Amadori”, 47014 Meldola, Italy
| | - Matthew T. Ballo
- West Cancer Center, 7945 Wolf River Boulevard, Germantown, TN 38138, USA
| | - Pradeep Patra
- West Cancer Center, 7945 Wolf River Boulevard, Germantown, TN 38138, USA
| | - Gil’ad N. Cohen
- Memorial Sloan Kettering Cancer Center, 1101 Hempstead Turnpike, Uniondale, NY 11553, USA; gil’
| | - Antonio L. Damato
- Memorial Sloan Kettering Cancer Center, 1101 Hempstead Turnpike, Uniondale, NY 11553, USA; gil’
| | - Yotam Shkedy
- Rambam Healthcare Campus, HaAliya HaShniya St 8, Haifa 3109601, Israel
| | - Robert B. Den
- Department of Radiation Oncology, Jefferson University, 1025 Walnut Street, Philadelphia, PA 19107, USA
- AlphaTau Medical, Kiryat HaMada St 5, Jerusalem 9777605, Israel
| | - Christopher A. Barker
- Memorial Sloan Kettering Cancer Center, 1101 Hempstead Turnpike, Uniondale, NY 11553, USA; gil’
| | - Tomer Charas
- Rambam Healthcare Campus, HaAliya HaShniya St 8, Haifa 3109601, Israel
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Nojima H, Kaida A, Matsuya Y, Uo M, Yoshimura RI, Arazi L, Miura M. DNA damage response in a 2D-culture model by diffusing alpha-emitters radiation therapy (Alpha-DaRT). Sci Rep 2024; 14:11468. [PMID: 38769339 PMCID: PMC11106084 DOI: 10.1038/s41598-024-62071-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Accepted: 05/13/2024] [Indexed: 05/22/2024] Open
Abstract
Diffusing alpha-emitters radiation therapy (Alpha-DaRT) is a unique method, in which interstitial sources carrying 224Ra release a chain of short-lived daughter atoms from their surface. Although DNA damage response (DDR) is crucial to inducing cell death after irradiation, how the DDR occurs during Alpha-DaRT treatment has not yet been explored. In this study, we temporo-spatially characterized DDR such as kinetics of DNA double-strand breaks (DSBs) and cell cycle, in two-dimensional (2D) culture conditions qualitatively mimicking Alpha-DaRT treatments, by employing HeLa cells expressing the Fucci cell cycle-visualizing system. The distribution of the alpha-particle pits detected by a plastic nuclear track detector, CR-39, strongly correlated with γH2AX staining, a marker of DSBs, around the 224Ra source, but the area of G2 arrested cells was more widely spread 24 h from the start of the exposure. Thereafter, close time-lapse observation revealed varying cell cycle kinetics, depending on the distance from the source. A medium containing daughter nuclides prepared from 224Ra sources allowed us to estimate the radiation dose after 24 h of exposure, and determine surviving fractions. The present experimental model revealed for the first time temporo-spatial information of DDR occurring around the source in its early stages.
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Affiliation(s)
- Hitomi Nojima
- Department of Dental Radiology and Radiation Oncology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
| | - Atsushi Kaida
- Department of Dental Radiology and Radiation Oncology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
| | - Yusuke Matsuya
- Nuclear Science and Engineering Center, Japan Atomic Energy Agency, 2-4 Shirakata, Tokai, Ibaraki, 319-1195, Japan
- Faculty of Health Sciences, Hokkaido University, Kita-12 Nishi-5, Kita-ku, Sapporo, Hokkaido, 060-0812, Japan
| | - Motohiro Uo
- Department of Advanced Biomaterials, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
| | - Ryo-Ichi Yoshimura
- Department of Radiation Therapeutics and Oncology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
| | - Lior Arazi
- Unit of Nuclear Engineering, Faculty of Engineering Sciences, Ben-Gurion University of the Negev, P.O.B. 653, 8410501, Be'er-Sheva, Israel
| | - Masahiko Miura
- Department of Dental Radiology and Radiation Oncology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan.
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Epstein L, Heger G, Roy A, Gannot I, Kelson I, Arazi L. The low-LET radiation contribution to the tumor dose in diffusing alpha-emitters radiation therapy. Med Phys 2024; 51:3020-3033. [PMID: 38096442 DOI: 10.1002/mp.16885] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 11/16/2023] [Accepted: 11/21/2023] [Indexed: 04/05/2024] Open
Abstract
BACKGROUND Diffusing alpha-emitters Radiation Therapy ("Alpha DaRT") is a new technique that enables the use of alpha particles for the treatment of solid tumors. Alpha DaRT employs interstitial sources carrying a few μ $\mu$ Ci of224 $^{224}$ Ra below their surface, designed to release a chain of short-lived atoms (progeny of224 $^{224}$ Ra) which emit alpha particles, along with beta, Auger, and conversion electrons, x- and gamma rays. These atoms diffuse around the source and create-primarily through their alpha decays-a lethal high-dose region measuring a few millimeters in diameter. PURPOSE While previous studies focused on the dose from the alpha emissions alone, this work addresses the electron and photon dose contributed by the diffusing atoms and by the atoms remaining on the source surface, for both a single Alpha DaRT source and multi-source lattices. This allows to evaluate the low-LET contribution to the tumor dose and tumor cell survival, and demonstrate the sparing of surrounding healthy tissue. METHODS The low-LET dose is calculated using the EGSnrc and FLUKA Monte Carlo (MC) codes. We compare the results of a simple line-source approximation with no diffusion to those of a full simulation, which implements a realistic source geometry and the spread of diffusing atoms. We consider two opposite scenarios: one with low diffusion and high212 $^{212}$ Pb leakage, and the other with high diffusion and low leakage. The low-LET dose in source lattices is calculated by superposition of single-source contributions. Its effect on cell survival is estimated with the linear quadratic model in the limit of low dose rate. RESULTS For sources carrying 3 μ $\umu$ Ci/cm224 $^{224}$ Ra arranged in a hexagonal lattice with 4 mm spacing, the minimal low-LET dose between sources is∼ 18 - 30 $\sim 18-30$ Gy for the two test cases and is dominated by the beta contribution. The low-LET dose drops below 5 Gy∼ 3 $\sim 3$ mm away from the outermost source in the lattice with an effective maximal dose rate of< 0.04 $<0.04$ Gy/h. The accuracy of the line-source/no-diffusion approximation is∼ 15 % $\sim 15\%$ for the total low-LET dose over clinically relevant distances (2-4 mm). The low-LET dose reduces tumor cell survival by a factor of∼ 2 - 200 $\sim 2-200$ . CONCLUSIONS The low-LET dose in Alpha DaRT can be modeled by conventional MC techniques with appropriate leakage corrections to the source activity. For 3 μ $\umu$ Ci/cm224 $^{224}$ Ra sources, the contribution of the low-LET dose can reduce cell survival inside the tumor by up to two orders of magnitude. The low-LET dose to surrounding healthy tissue is negligible. Increasing source activities by a factor of 5 can bring the low-LET dose itself to therapeutic levels, in addition to the high-LET dose contributed by alpha particles, leading to a "self-boosted" Alpha DaRT configuration, and potentially allowing to increase the lattice spacing.
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Affiliation(s)
- Lior Epstein
- Unit of Nuclear Engineering, Faculty of Engineering Sciences, Ben-Gurion University of the Negev, Be'er-Sheva, Israel
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv, Israel
- Soreq Nuclear Research Center, Yavne, Israel
| | - Guy Heger
- Unit of Nuclear Engineering, Faculty of Engineering Sciences, Ben-Gurion University of the Negev, Be'er-Sheva, Israel
| | - Arindam Roy
- Unit of Nuclear Engineering, Faculty of Engineering Sciences, Ben-Gurion University of the Negev, Be'er-Sheva, Israel
| | - Israel Gannot
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv, Israel
| | - Itzhak Kelson
- School of Physics and Astronomy, Faculty of Exact Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Lior Arazi
- Unit of Nuclear Engineering, Faculty of Engineering Sciences, Ben-Gurion University of the Negev, Be'er-Sheva, Israel
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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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Fedorchenko D, Alani S. Simulation of particle release for Diffusing Alpha-Emitters Radiation Therapy. Appl Radiat Isot 2023; 197:110825. [PMID: 37099829 DOI: 10.1016/j.apradiso.2023.110825] [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: 11/25/2022] [Revised: 04/09/2023] [Accepted: 04/13/2023] [Indexed: 04/28/2023]
Abstract
We used Monte Carlo simulations to study release of 224Ra daughter nuclei from the seed used for Diffusing Alpha-Emitters Radiation Therapy (DART). Calculated desorption probabilities for 216Po (15%) and 212Pb (12%) showed that they make a significant contribution to total release from the seed. We also showed that the dose to tissue from decays inside the 10 mm long seed exceeds 2.9 Gy for initial 224Ra activity of 3 μCi (111 kBq).
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Affiliation(s)
| | - Shlomi Alani
- Ziv Medical Center, Derech HaRambam, Zefat, 13100, Israel.
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Heger G, Dumančić M, Roy A, Arazi L. Alpha dose modeling in diffusing alpha-emitters radiation therapy. Part II: Lattice studies. Med Phys 2023; 50:1812-1823. [PMID: 36517936 DOI: 10.1002/mp.16155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 12/01/2022] [Accepted: 12/02/2022] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Diffusing alpha-emitters radiation therapy ("DaRT") is a new method, presently in clinical trials, which allows treating solid tumors by alpha particles. DaRT relies on interstitial seeds carrying μCi-level 224 Ra activity on their surface, which release a chain of short-lived alpha emitters that spread throughout the tumor volume primarily by diffusion. Alpha dose calculations in DaRT are based on describing the transport of alpha emitting atoms, requiring new modeling techniques. PURPOSE A previous study introduced a simplified framework, the "diffusion-leakage (DL) model," for DaRT alpha dose calculations, and employed it to a point source, as a basic building block of arbitrary configurations of line sources. The aim of this work, which is divided into two parts, is to extend the model to realistic seed geometries (in Part I), and to employ single-seed calculations to study the properties of DaRT seed lattices (Part II). Such calculations can serve as a pragmatic guide for treatment planning in future clinical trials. METHODS We employ the superposition of single-seed solutions, developed in Part I, to study the alpha dose in DaRT seed lattices and investigate the sensitivity of the required seed activity and spacing to changes in the DL model parameters and to seed placement errors. RESULTS We show that the rapid fall-off of the dose, which guarantees sparing healthy tissue already 2-3 mm away from the tumor, strongly favors a hexagonal, rather than square, seed placement pattern. Realistic variations in the seed manufacturing parameters (224 Ra activity and emission rate of its daughters) are shown to have a negligible effect on the required lattice spacing. On the other hand, tumor parameters (i.e., diffusion lengths and 212 Pb leakage probability), as well as seed placement errors, have a significant effect. CONCLUSIONS In most cases, hexagonal lattice spacing on the scale of ∼3.5-4.5 mm using seeds carrying a few μCi/cm 224 Ra will enable overcoming realistic uncertainties in measured tumor environment parameters, as well as seed placement errors, and result in therapeutically relevant alpha dose levels.
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Affiliation(s)
- Guy Heger
- Unit of Nuclear Engineering, Faculty of Engineering Sciences, Ben-Gurion University of the Negev, Be'er-Sheva, Israel
| | - Mirta Dumančić
- Unit of Nuclear Engineering, Faculty of Engineering Sciences, Ben-Gurion University of the Negev, Be'er-Sheva, Israel
| | - Arindam Roy
- Unit of Nuclear Engineering, Faculty of Engineering Sciences, Ben-Gurion University of the Negev, Be'er-Sheva, Israel
| | - Lior Arazi
- Unit of Nuclear Engineering, Faculty of Engineering Sciences, Ben-Gurion University of the Negev, Be'er-Sheva, Israel
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Heger G, Roy A, Dumančić M, Arazi L. Alpha dose modeling in diffusing alpha-emitters radiation therapy-Part I: single-seed calculations in one and two dimensions. Med Phys 2023; 50:1793-1811. [PMID: 36464914 DOI: 10.1002/mp.16145] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Revised: 09/01/2022] [Accepted: 09/29/2022] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Diffusing alpha-emitters Radiation Therapy ("DaRT") is a new method, presently in clinical trials, which allows treating solid tumors by alpha particles. DaRT relies on interstitial seeds carrying μCi-level 224 Ra activity below their surface, which release a chain of short-lived alpha emitters that spread throughout the tumor volume primarily by diffusion. Alpha dose calculations in DaRT are based on describing the transport of alpha emitting atoms, requiring new modeling techniques. PURPOSE A previous study introduced a simplified framework, the "Diffusion-Leakage (DL) model", for DaRT alpha dose calculations, and employed it to a point source, as a basic building block of arbitrary configurations of line sources. The aim of this work, which is divided into two parts, is to extend the model to realistic seed geometries (in Part I), and to employ single-seed calculations to study the properties of DaRT seed lattices (Part II). Such calculations can serve as a pragmatic guide for treatment planning in future clinical trials. METHODS We derive a closed-form asymptotic solution for an infinitely long cylindrical source, and extend it to an approximate time-dependent expression that assumes a uniform temporal profile at all radial distances from the source. We then develop a finite-element one-dimensional numerical scheme for a complete time-dependent solution of this geometry and validate it against the closed-form expressions. Finally, we discuss a two-dimensional axisymmetric scheme for a complete time-dependent solution for a seed of finite diameter and length. Different solutions are compared over the relevant parameter space, providing guidelines on their usability and limitations. RESULTS We show that approximating the seed as a finite line source comprised of point-like segments significantly underestimates the correct alpha dose, as predicted by the full two-dimensional calculation. The time-dependent one-dimensional solution is shown to coincide to sub-percent-level with the two-dimensional calculation in the seed midplane, and maintains an accuracy of a few percent up to ∼2 mm from the seed edge. CONCLUSIONS For actual treatment plans, the full two-dimensional solution should be used to generate dose lookup tables, similarly to the TG-43 format employed in conventional brachytherapy. Given the accuracy of the one-dimensional solution up to ∼2 mm from the seed edge it can be used for efficient parametric studies of DaRT seed lattices.
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Affiliation(s)
- Guy Heger
- Unit of Nuclear Engineering, Faculty of Engineering Sciences, Ben-Gurion University of the Negev, Be'er-Sheva, Israel
| | - Arindam Roy
- Unit of Nuclear Engineering, Faculty of Engineering Sciences, Ben-Gurion University of the Negev, Be'er-Sheva, Israel
| | - Mirta Dumančić
- Unit of Nuclear Engineering, Faculty of Engineering Sciences, Ben-Gurion University of the Negev, Be'er-Sheva, Israel
| | - Lior Arazi
- Unit of Nuclear Engineering, Faculty of Engineering Sciences, Ben-Gurion University of the Negev, Be'er-Sheva, Israel
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Nishri Y, Vatarescu M, Luz I, Epstein L, Dumančić M, Del Mare S, Shai A, Schmidt M, Deutsch L, Den RB, Kelson I, Keisari Y, Arazi L, Cooks T, Domankevich V. Diffusing alpha-emitters radiation therapy in combination with temozolomide or bevacizumab in human glioblastoma multiforme xenografts. Front Oncol 2022; 12:888100. [PMID: 36237307 PMCID: PMC9552201 DOI: 10.3389/fonc.2022.888100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 09/02/2022] [Indexed: 11/13/2022] Open
Abstract
Glioblastoma multiforme (GBM) is at present an incurable disease with a 5-year survival rate of 5.5%, despite improvements in treatment modalities such as surgery, radiation therapy, chemotherapy [e.g., temozolomide (TMZ)], and targeted therapy [e.g., the antiangiogenic agent bevacizumab (BEV)]. Diffusing alpha-emitters radiation therapy (DaRT) is a new modality that employs radium-224-loaded seeds that disperse alpha-emitting atoms inside the tumor. This treatment was shown to be effective in mice bearing human-derived GBM tumors. Here, the effect of DaRT in combination with standard-of-care therapies such as TMZ or BEV was investigated. In a viability assay, the combination of alpha radiation with TMZ doubled the cytotoxic effect of each of the treatments alone in U87 cultured cells. A colony formation assay demonstrated that the surviving fraction of U87 cells treated by TMZ in combination with alpha irradiation was lower than was achieved by alpha- or x-ray irradiation as monotherapies, or by x-ray combined with TMZ. The treatment of U87-bearing mice with DaRT and TMZ delayed tumor development more than the monotherapies. Unlike other radiation types, alpha radiation did not increase VEGF secretion from U87 cells in culture. BEV treatment introduced several days after DaRT implantation improved tumor control, compared to BEV or DaRT as monotherapies. The combination was also shown to be superior when starting BEV administration prior to DaRT implantation in large tumors relative to the seed size. BEV induced a decrease in CD31 staining under DaRT treatment, increased the diffusive spread of 224Ra progeny atoms in the tumor tissue, and decreased their clearance from the tumor through the blood. Taken together, the combinations of DaRT with standard-of-care chemotherapy or antiangiogenic therapy are promising approaches, which may improve the treatment of GBM patients.
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Affiliation(s)
- Yossi Nishri
- Translational Research Laboratory, Alpha Tau Medical, Jerusalem, Israel
| | - Maayan Vatarescu
- Translational Research Laboratory, Alpha Tau Medical, Jerusalem, Israel
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University, Beer-Sheva, Israel
| | - Ishai Luz
- Translational Research Laboratory, Alpha Tau Medical, Jerusalem, Israel
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University, Beer-Sheva, Israel
| | - Lior Epstein
- Unit of Nuclear Engineering, Faculty of Engineering Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
- Radiation Protection Department, Soreq Nuclear Research Center, Yavne, Israel
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv, Israel
| | - Mirta Dumančić
- Unit of Nuclear Engineering, Faculty of Engineering Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Sara Del Mare
- Translational Research Laboratory, Alpha Tau Medical, Jerusalem, Israel
| | - Amit Shai
- Translational Research Laboratory, Alpha Tau Medical, Jerusalem, Israel
| | | | - Lisa Deutsch
- Biostatistics Department, BioStats Statistical Consulting Ltd., Maccabim, Israel
| | - Robert B. Den
- Translational Research Laboratory, Alpha Tau Medical, Jerusalem, Israel
- Department of Radiation Oncology, Urology, and Cancer Biology, Thomas Jefferson University, Philadelphia, PA, United States
| | - Itzhak Kelson
- School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Yona Keisari
- Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Lior Arazi
- Unit of Nuclear Engineering, Faculty of Engineering Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
- *Correspondence: Lior Arazi, ; Tomer Cooks, ; Vered Domankevich,
| | - Tomer Cooks
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University, Beer-Sheva, Israel
- *Correspondence: Lior Arazi, ; Tomer Cooks, ; Vered Domankevich,
| | - Vered Domankevich
- Translational Research Laboratory, Alpha Tau Medical, Jerusalem, Israel
- *Correspondence: Lior Arazi, ; Tomer Cooks, ; Vered Domankevich,
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10
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A New Approach for a Safe and Reproducible Seeds Positioning for Diffusing Alpha-Emitters Radiation Therapy of Squamous Cell Skin Cancer: A Feasibility Study. Cancers (Basel) 2022; 14:cancers14010240. [PMID: 35008404 PMCID: PMC8750419 DOI: 10.3390/cancers14010240] [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] [Received: 11/19/2021] [Revised: 12/22/2021] [Accepted: 12/31/2021] [Indexed: 12/11/2022] Open
Abstract
Simple Summary The Diffusing Alpha-emitters Radiation Therapy (DaRT) is a novel brachytherapy technique employing 224-radium enriched seeds releasing short-lived alpha-emitting atoms into the tumour. DaRT overcomes the main obstacle in employing alpha radiation for cancer treatments in liquid and solid media caused by their short range. The aim of the study is to improve the DaRT technique with an external radio-opaque template that can help clinicians predict the correct number of sources to achieve tumour coverage. Furthermore, the template is used to aid clinicians in visualizing lesions and their eventual subcutaneous extension. Finally, it is also utilized on treatment day to ensure that the sources are properly inserted into the tumour. Abstract The purpose of this study is to discuss how to use an external radio-opaque template in the Diffusing Alpha-emitters Radiation Therapy (DaRT) technique’s pre-planning and treatment stages. This device would help to determine the proper number of sources for tumour coverage, accounting for subcutaneous invasion and augmenting DaRT safety. The procedure will be carried out in a first phase on a phantom and then applied to a clinical case. A typical DaRT procedure workflow comprises steps like tumour measurements and delineation, source number assessment, and therapy administration. As a first step, an adhesive fiberglass mesh (spaced by 2 mm) tape was applied on the skin of the patient and employed as frame of reference. A physician contoured the lesion and marked the entrance points for the needles with a radio opaque ink marker. According to the radio opaque marks and metabolic uptake the clinical target volume was defined, and with a commercial brachytherapy treatment planning system (TPS) it was possible to simulate and adjust the spatial seeds distribution. After the implant procedure a CT was again performed to check the agreement between simulations and seeds positions. With the procedure described above it was possible to simulate a DaRT procedure on a phantom in order to train physicians and subsequently apply the novel approach on patients, outlining the major issues involved in the technique. The present work innovates and supports DaRT technique for the treatment of cutaneous cancers, improving its efficacy and safety.
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11
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Napoli E, Bønsdorff TB, Jorstad IS, Bruland ØS, Larsen RH, Westrøm S. Radon-220 diffusion from 224Ra-labeled calcium carbonate microparticles: Some implications for radiotherapeutic use. PLoS One 2021; 16:e0248133. [PMID: 33662039 PMCID: PMC7932545 DOI: 10.1371/journal.pone.0248133] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 02/21/2021] [Indexed: 01/08/2023] Open
Abstract
Alpha-particle emitting radionuclides continue to be the subject of medical research because of their high energy and short range of action that facilitate effective cancer therapies. Radium-224 (224Ra) is one such candidate that has been considered for use in combating micrometastatic disease. In our prior studies, a suspension of 224Ra-labeled calcium carbonate (CaCO3) microparticles was designed as a local therapy for disseminated cancers in the peritoneal cavity. The progenies of 224Ra, of which radon-220 (220Rn) is the first, together contribute three of the four alpha particles in the decay chain. The proximity of the progenies to the delivery site at the time of decay of the 224Ra-CaCO3 microparticles can impact its therapeutic efficacy. In this study, we show that the diffusion of 220Rn was reduced in labeled CaCO3 suspensions as compared with cationic 224Ra solutions, both in air and liquid volumes. Furthermore, free-floating lead-212 (212Pb), which is generated from released 220Rn, had the potential to be re-adsorbed onto CaCO3 microparticles. Under conditions mimicking an in vivo environment, more than 70% of the 212Pb was adsorbed onto the CaCO3 at microparticle concentrations above 1 mg/mL. Further, the diffusion of 220Rn seemed to occur whether the microparticles were labeled by the surface adsorption of 224Ra or if the 224Ra was incorporated into the bulk of the microparticles. The therapeutic benefit of differently labeled 224Ra-CaCO3 microparticles after intraperitoneal administration was similar when examined in mice bearing intraperitoneal ovarian cancer xenografts. In conclusion, both the release of 220Rn and re-adsorption of 212Pb are features that have implications for the radiotherapeutic use of 224Ra-labeled CaCO3 microparticles. The release of 220Rn through diffusion may extend the effective range of alpha-particle dose deposition, and the re-adsorption of the longer lived 212Pb onto the CaCO3 microparticles may enhance the retention of this nuclide in the peritoneal cavity.
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Affiliation(s)
- Elisa Napoli
- Oncoinvent AS, Oslo, Norway
- Institute of Clinical Medicine, University of Oslo, Oslo, Norway
- Department of Radiation Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
| | | | | | - Øyvind S. Bruland
- Institute of Clinical Medicine, University of Oslo, Oslo, Norway
- Department of Oncology, Oslo University Hospital, Oslo, Norway
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12
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Targeted Alpha Therapy: Progress in Radionuclide Production, Radiochemistry, and Applications. Pharmaceutics 2020; 13:pharmaceutics13010049. [PMID: 33396374 PMCID: PMC7824049 DOI: 10.3390/pharmaceutics13010049] [Citation(s) in RCA: 77] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 12/15/2020] [Accepted: 12/23/2020] [Indexed: 12/17/2022] Open
Abstract
This review outlines the accomplishments and potential developments of targeted alpha (α) particle therapy (TAT). It discusses the therapeutic advantages of the short and highly ionizing path of α-particle emissions; the ability of TAT to complement and provide superior efficacy over existing forms of radiotherapy; the physical decay properties and radiochemistry of common α-emitters, including 225Ac, 213Bi, 224Ra, 212Pb, 227Th, 223Ra, 211At, and 149Tb; the production techniques and proper handling of α-emitters in a radiopharmacy; recent preclinical developments; ongoing and completed clinical trials; and an outlook on the future of TAT.
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13
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Domankevich V, Efrati M, Schmidt M, Glikson E, Mansour F, Shai A, Cohen A, Zilberstein Y, Flaisher E, Galalae R, Kelson I, Keisari Y. RIG-1-Like Receptor Activation Synergizes With Intratumoral Alpha Radiation to Induce Pancreatic Tumor Rejection, Triple-Negative Breast Metastases Clearance, and Antitumor Immune Memory in Mice. Front Oncol 2020; 10:990. [PMID: 32766128 PMCID: PMC7379859 DOI: 10.3389/fonc.2020.00990] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 05/19/2020] [Indexed: 12/19/2022] Open
Abstract
Diffusing alpha-emitting radiation therapy (DaRT) employs intratumoral Ra-224-coated seeds that efficiently destroy solid tumors by slowly releasing alpha-emitting atoms inside the tumor. In immunogenic tumor models, DaRT was shown to activate systemic antitumor immunity. Agonists of the membrane-bound toll-like receptors (TLRs) enhanced these effects and led to tumor rejection. Here, we examined the combination of DaRT with agents that activate a different type of pattern recognition receptors, the cytoplasmatic RIG1-like receptors (RLRs). In response to cytoplasmatic viral dsRNA, RLRs activate an antiviral immune response that includes the elevation of antigen presentation. Thus, it was postulated that in low-immunogenic tumor models, RLR activation in tumor cells prior to the induction of their death by DaRT will be superior compared to TLR activation. Intratumoral cytoplasmatic delivery of the dsRNA mimic polyIC by polyethylenimine (PEI), was used to activate RLR, while polyIC without PEI was used to activate TLR. PolyIC(PEI) prior to DaRT synergistically retarded 4T1 triple-negative breast tumors and metastasis development more efficiently than polyIC and rejected panc02 pancreatic tumors in some of the treated mice. Splenocytes from treated mice, adoptively transferred to naive mice in combination with 4T1 tumor cells, delayed tumor development compared to naïve splenocytes. Low-dose cyclophosphamide, known to reduce T regulatory cell number, enhanced the effect of DaRT and polyIC(PEI) and led to high long-term survival rates under neoadjuvant settings, which confirmed metastasis clearance. The epigenetic drug decitabine, known to activate RLR in low doses, was given intraperitoneally prior to DaRT and caused tumor growth retardation, similar to local polyIC(PEI). The systemic and/or local administration of RLR activators was also tested in the squamous cell carcinoma (SCC) tumor model SQ2, in which a delay in tumor re-challenge development was demonstrated. We conclude that RIG-I-like activation prior to intratumoral alpha radiation may serve as a potent combination technique to reduce both tumor growth and the spread of distant metastases in low-immunogenic and metastatic tumor models.
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Affiliation(s)
- Vered Domankevich
- Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv-Yafo, Israel.,Alpha Tau Medical, Tel Aviv-Yafo, Israel
| | - Margalit Efrati
- Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv-Yafo, Israel.,Alpha Tau Medical, Tel Aviv-Yafo, Israel
| | - Michael Schmidt
- Alpha Tau Medical, Tel Aviv-Yafo, Israel.,Sackler Faculty of Exact Sciences, School of Physics and Astronomy, Tel Aviv University, Tel Aviv-Yafo, Israel
| | - Eran Glikson
- Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv-Yafo, Israel.,Department of Otolaryngology, Head and Neck Surgery, Sheba Medical Center, Tel HaShomer, Israel
| | - Fairuz Mansour
- Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv-Yafo, Israel
| | - Amit Shai
- Alpha Tau Medical, Tel Aviv-Yafo, Israel
| | - Adi Cohen
- Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv-Yafo, Israel
| | - Yael Zilberstein
- Sackler Cellular and Molecular Imaging Center, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv-Yafo, Israel
| | | | - Razvan Galalae
- MedAustron, Wiener Neustadt, Austria.,Medical Faculty, Christian-Albrechts University, Kiel, Germany
| | - Itzhak Kelson
- Sackler Faculty of Exact Sciences, School of Physics and Astronomy, Tel Aviv University, Tel Aviv-Yafo, Israel
| | - Yona Keisari
- Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv-Yafo, Israel
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14
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Arazi L. Diffusing alpha-emitters radiation therapy: approximate modeling of the macroscopic alpha particle dose of a point source. Phys Med Biol 2020; 65:015015. [PMID: 31766047 DOI: 10.1088/1361-6560/ab5b73] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Diffusing alpha-emitters radiation therapy ('DaRT') is a new cancer-treatment modality, which enables treating solid tumors by alpha particles. The treatment utilizes implantable seeds embedded with a low activity of radium-224. Each seed continuously emits the short-lived alpha-emitting daughters of radium-224, which spread over several mm around it, creating a 'kill region' of high alpha-particle dose. DaRT is presently tested in clinical trials, starting with locally advanced and recurrent squamous cell carcinoma (SCC) of the skin and head and neck, with promising results with respect to both efficacy and safety. This work aims to provide a simple model which can serve as a zero-order approximation for DaRT dosimetry, allowing for calculating the macroscopic alpha particle dose of a point source, as a basis for more realistic source geometries. The model consists of diffusion equations for radon-220, lead-212 and bismuth-212, with the other short-lived daughters in local secular equilibrium. For simplicity, the medium is assumed to be homogeneous, isotropic and time-independent. Vascular effects are accounted for by effective diffusion and clearance terms. To leading order, the alpha particle dose can be described by simple analytic expressions, which shed light on the underlying physics. The calculations demonstrate that, for a reasonable choice of model parameters, therapeutic alpha-particle dose levels are obtained over a region measuring 4-7 mm in diameter for sources carrying a few [Formula: see text]Ci of radium-224. The model predictions served as the basis for treatment planning in the SCC clinical trial, where treatments employing DaRT seeds carrying 2 [Formula: see text]Ci of radium-224 and spaced 5 mm apart resulted in ∼[Formula: see text] complete response of the treated tumors with no observed radiation-induced toxicity. The promising results of the SCC clinical trial indicate that in spite of its approximate nature, the simple diffusion-based dosimetry model provides a quantitative starting point for DaRT treatment planning.
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Affiliation(s)
- Lior Arazi
- Unit of Nuclear Engineering, Faculty of Engineering Sciences, Ben-Gurion University of the Negav, POB 653 Beer-Sheva 8410501, Israel
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15
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Popovtzer A, Rosenfeld E, Mizrachi A, Bellia SR, Ben-Hur R, Feliciani G, Sarnelli A, Arazi L, Deutsch L, Kelson I, Keisari Y. Initial Safety and Tumor Control Results From a "First-in-Human" Multicenter Prospective Trial Evaluating a Novel Alpha-Emitting Radionuclide for the Treatment of Locally Advanced Recurrent Squamous Cell Carcinomas of the Skin and Head and Neck. Int J Radiat Oncol Biol Phys 2019; 106:571-578. [PMID: 31759075 DOI: 10.1016/j.ijrobp.2019.10.048] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 10/04/2019] [Accepted: 10/21/2019] [Indexed: 11/30/2022]
Abstract
PURPOSE Our purpose was to report the feasibility and safety of diffusing alpha-emitter radiation therapy (DaRT), which entails the interstitial implantation of a novel alpha-emitting brachytherapy source, for the treatment of locally advanced and recurrent squamous cancers of the skin and head and neck. METHODS AND MATERIALS This prospective first-in-human, multicenter clinical study evaluated 31 lesions in 28 patients. The primary objective was to determine the feasibility and safety of this approach, and the secondary objectives were to evaluate the initial tumor response and local progression-free survival. Eligibility criteria included all patients with biopsy-proven squamous cancers of the skin and head and neck with either primary tumors or recurrent/previously treated disease by either surgery or prior external beam radiation therapy; 13 of 31 lesions (42%) had received prior radiation therapy. Toxicity was evaluated according to the Common Terminology Criteria for Adverse Events version 4.03. Tumor response was assessed at 30 to 45 days at a follow-up visit using the Response Evaluation Criteria in Solid Tumors, version 1.1. Median follow-up time was 6.7 months. RESULTS Acute toxicity included mostly local pain and erythema at the implantation site followed by swelling and mild skin ulceration. For pain and grade 2 skin ulcerations, 90% of patients had resolution within 3 to 5 weeks. Complete response to the Ra-224 DaRT treatment was observed in 22 lesions (22/28; 78.6%); 6 lesions (6/28, 21.4%) manifested a partial response (>30% tumor reduction). Among the 22 lesions with a complete response, 5 (22%) developed a subsequent local relapse at the site of DaRT implantation at a median time of 4.9 months (range, 2.43-5.52 months). The 1-year local progression-free survival probability at the implanted site was 44% overall (confidence interval [CI], 20.3%-64.3%) and 60% (95% CI, 28.61%-81.35%) for complete responders. Overall survival rates at 12 months post-DaRT implantation were 75% (95% CI, 46.14%-89.99%) among all patients and 93% (95% CI, 59.08%-98.96%) among complete responders. CONCLUSIONS Alpha-emitter brachytherapy using DaRT achieved significant tumor responses without grade 3 or higher toxicities observed. Longer follow-up observations and larger studies are underway to validate these findings.
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Affiliation(s)
- A Popovtzer
- Rabin Medical Center Petah Tiqva, Petah Tiqva, Israel; Tel Aviv University, Tel Aviv, Israel.
| | - E Rosenfeld
- Rabin Medical Center Petah Tiqva, Petah Tiqva, Israel
| | - A Mizrachi
- Rabin Medical Center Petah Tiqva, Petah Tiqva, Israel; Tel Aviv University, Tel Aviv, Israel
| | - S R Bellia
- Instituto Scientifico Romagnolo per Lo Studio e la Cura dei Tumori, (IRST)-IRCCS, Meldola, Italy
| | - R Ben-Hur
- Rabin Medical Center Petah Tiqva, Petah Tiqva, Israel
| | - G Feliciani
- Instituto Scientifico Romagnolo per Lo Studio e la Cura dei Tumori, (IRST)-IRCCS, Meldola, Italy
| | - A Sarnelli
- Instituto Scientifico Romagnolo per Lo Studio e la Cura dei Tumori, (IRST)-IRCCS, Meldola, Italy
| | - L Arazi
- Ben-Gurion University of the Negev, Beersheba, Israel
| | - L Deutsch
- BioStats Statistical Consult, Merkez Renanim, Maccabim Israel
| | - I Kelson
- Tel Aviv University, Tel Aviv, Israel
| | - Y Keisari
- Tel Aviv University, Tel Aviv, Israel
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16
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Clinical evidence of abscopal effect in cutaneous squamous cell carcinoma treated with diffusing alpha emitters radiation therapy: a case report. J Contemp Brachytherapy 2019; 11:449-457. [PMID: 31749854 PMCID: PMC6854861 DOI: 10.5114/jcb.2019.88138] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 07/25/2019] [Indexed: 12/19/2022] Open
Abstract
Purpose Alpha particle treatments could enhance the probability of an immune response, which can lead to abscopal effects (AE). We report a case of a patient affected by multiple cutaneous squamous cell carcinoma (cSCC). After the treatment with diffusing alpha emitters radiation therapy (DaRT) of one lesion, an AE was observed on at least two distant ones. Material and methods We investigated a case of a 65-year-old female patient with multiple synchronous lesions of the skin of lower limbs confirmed by a biopsy. Patient was enrolled in a clinical trial N.CTP-SCC-00 (NCT03015883), with the objective to assess effectiveness of DaRT technique. DaRT is based on the insertion of locally 224Ra-loaded seeds in a clinical target volume (CTV). Treatment plan with positron emission tomography/computed tomography (PET/CT) was used to entirely cover the CTV. Follow-up and biopsy evaluations were employed to outline the patient outcome. Results We performed seeds implantation according to the Paris system. At 28th day, an evident lesion shrinkage with a persistent minimal area of hyperkeratosis was noted. 76 days after implantation, a complete remission of the treated lesion was observed and an evident reduction of the area with two more distant lesion, which could be associated to an immune-mediated response. One year after the treatment, a complete remission of treated lesion was observed as well as spontaneous regression of untreated distant ones. Conclusions In this study, we reported evidences of an AE in cSCC stimulated by radiation and possibly mediated by immune system. In the next DaRT treatments, our intent is to monitor T-lymphocytes variations in peripheral blood in order to demonstrate indirect activation of the immune system mediated by radiation also in patients with solitary lesions, in which, by definition, an AE cannot be observed.
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Domankevich V, Cohen A, Efrati M, Schmidt M, Rammensee HG, Nair SS, Tewari A, Kelson I, Keisari Y. Combining alpha radiation-based brachytherapy with immunomodulators promotes complete tumor regression in mice via tumor-specific long-term immune response. Cancer Immunol Immunother 2019; 68:1949-1958. [PMID: 31637474 PMCID: PMC6877484 DOI: 10.1007/s00262-019-02418-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 10/10/2019] [Indexed: 12/11/2022]
Abstract
Diffusing alpha-emitters radiation therapy (DaRT) is the only known method for treating solid tumors with highly destructive alpha radiation. More importantly, as a monotherapy, DaRT has been shown to induce a systemic antitumor immune response following tumor ablation. Here, immunomodulatory strategies to boost the antitumor immune response induced by DaRT, and the response specificity, were investigated in the colon cancer CT26 mouse model. Local treatment prior to DaRT, with the TLR3 agonist poly I:C, was sufficient to inhibit tumor growth relative to poly I:C or DaRT alone. DaRT used in combination with the TLR9 agonist CpG, or with the TLR1/2 agonist XS15 retarded tumor growth and increased tumor-rejection rates, compared to DaRT alone, curing 41% and 20% of the mice, respectively. DaRT in combination with CpG, the Treg inhibitor cyclophosphamide, and the MDSC inhibitor sildenafil, cured 51% of the animals, compared to only 6% and 0% cure when immunomodulation or DaRT was used alone, respectively. Challenge and Winn assays revealed that these high cure rates involved a specific immunological memory against CT26 antigens. We suggest that DaRT acts in synergy with immunomodulation to induce a specific and systemic antitumor immune response. This strategy may serve as a safe and efficient method not only for tumor ablation, but also for in situ vaccination of cancer patients.
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Affiliation(s)
- Vered Domankevich
- Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel Aviv University, P.O. Box 39040, 6997801, Tel Aviv, Israel
| | - Adi Cohen
- Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel Aviv University, P.O. Box 39040, 6997801, Tel Aviv, Israel
| | - Margalit Efrati
- Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel Aviv University, P.O. Box 39040, 6997801, Tel Aviv, Israel
| | - Michael Schmidt
- School of Physics and Astronomy, Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv, Israel
- Alpha Tau Medical, Tel Aviv, Israel
| | - Hans-Georg Rammensee
- Department of Immunology, Institute for Cell Biology, University of Tübingen, Tübingen, Germany
| | - Sujit S Nair
- Department of Urology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Ashutosh Tewari
- Department of Urology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Itzhak Kelson
- School of Physics and Astronomy, Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv, Israel
- Alpha Tau Medical, Tel Aviv, Israel
| | - Yona Keisari
- Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel Aviv University, P.O. Box 39040, 6997801, Tel Aviv, Israel.
- Alpha Tau Medical, Tel Aviv, Israel.
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18
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Confino H, Hochman I, Efrati M, Schmidt M, Umansky V, Kelson I, Keisari Y. Tumor ablation by intratumoral Ra-224-loaded wires induces anti-tumor immunity against experimental metastatic tumors. Cancer Immunol Immunother 2015; 64:191-9. [PMID: 25326364 PMCID: PMC11029790 DOI: 10.1007/s00262-014-1626-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Accepted: 10/06/2014] [Indexed: 12/11/2022]
Abstract
INTRODUCTION The current systemic anti-metastatic treatment is chemotherapy. Chemotherapy reacts mostly against replicating cells, which makes this therapy not specific. Moreover, resting cancer cells will not be destroyed. A better alternative is an engagement of the host immune system to react against tumor-associated antigens. An efficient immune-stimulating technique is an ablation of the tumor that results in the release of tumor antigens. Our ablation strategy is an innovative alpha-radiation-based technology, diffusing alpha-emitters radiation therapy (DaRT), which efficiently destroys local tumors and provides thereby an antigenic supply for antigen-presenting cells to stimulate T cells. METHODS Mice bearing weakly immunogenic DA3 adenocarcinoma or highly immunogenic CT26 colon carcinoma were treated by DaRT. Anti-tumor immune responses following tumor destruction were evaluated by (1) the resistance to a tumor challenge; (2) scanning by a CT imaging device for elimination of lung metastases; (3) improved tumor control when combining DaRT with an immunoadjuvant (CpG). RESULTS CT26 model: 63-77 % of DaRT-treated mice became resistant to a re-inoculated tumor compared to 29-33 % resistant mice in the control. DA3 model: (1) The growth rate of challenge tumors was the lowest in mice which their primary tumor was treated by DaRT. (2) Most (93 %) mice in the control group developed lung metastases compared to 56 % in the DaRT group. (3) Combining DaRT with CpG resulted in a better control of the primary tumor. Our study offers a technique to eliminate local and distant malignant cells, regardless of their replication status, by stimulating specific anti-tumor immunity through the supply of tumor antigens from the destroyed tumor.
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Affiliation(s)
- Hila Confino
- Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel Aviv University, P.O. Box 39040, Tel Aviv, Israel
| | - Ilan Hochman
- Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel Aviv University, P.O. Box 39040, Tel Aviv, Israel
| | - Margalit Efrati
- Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel Aviv University, P.O. Box 39040, Tel Aviv, Israel
| | - Michael Schmidt
- Sackler Faculty of Exact Sciences, School of Physics and Astronomy, Tel Aviv University, Tel Aviv, Israel
| | - Viktor Umansky
- Skin Cancer Unit, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Department of Dermatology, Venereology and Allergology, University Medical Center Mannheim, Ruprecht-Karl University of Heidelberg Mannheim, 69120 Heidelberg, Germany
| | - Itzhak Kelson
- Sackler Faculty of Exact Sciences, School of Physics and Astronomy, Tel Aviv University, Tel Aviv, Israel
| | - Yona Keisari
- Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel Aviv University, P.O. Box 39040, Tel Aviv, Israel
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Reitkopf-Brodutch S, Confino H, Schmidt M, Cooks T, Efrati M, Arazi L, Rath-Wolfson L, Marshak G, Kelson I, Keisari Y. Ablation of experimental colon cancer by intratumoral 224Radium-loaded wires is mediated by alpha particles released from atoms which spread in the tumor and can be augmented by chemotherapy. Int J Radiat Biol 2015; 91:179-86. [PMID: 25179346 DOI: 10.3109/09553002.2015.959666] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE We developed (224)Ra-loaded wires, which release by recoil alpha emitting nuclei into solid tumors and cause tumor cell killing. This research examined if the major damage was inflicted by alpha particles emitted from these atoms or by direct gamma and beta emissions from the inserted wires. We also examined the efficacy of this treatment against colon cancer in combination with chemotherapy. MATERIALS AND METHODS Mouse colon carcinomas (CT-26 xenografts), treated by intra-tumoral radioactive wires loaded with (224)Ra atoms were monitored for effects on tumor growth, intratumoral tissue damage and distribution of alpha emitting atoms. The effects were compared with those of (224)Ra-loaded wires coated with poly methyl methacrylate (PMMA), which blocks atom recoil. Similar experiments were performed with radioactive wires combined with systemic 5-FU. RESULTS (224)Ra-loaded wires inhibited tumor growth and formed necrotic areas inside the tumor. PMMA coated wires did not inhibit tumor growth, and caused minor intratumoral damage. Autoradiography images of tumors treated with (224)Ra-loaded wires revealed a spread of alpha emitters over several mm, whereas PMMA-coated wires showed no such spread. Injection of 5-FU with (224)Ra-loaded wires augmented tumor growth retardation and cure. CONCLUSIONS (224)Ra-loaded wires ablate solid tumors by the release of alpha-particle emitting atoms inside the tissue, an effect that can be enhanced by combining this method with chemotherapy.
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Affiliation(s)
- Shira Reitkopf-Brodutch
- Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel Aviv University , Tel Aviv , Israel
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Hobbs RF, Song H, Huso DL, Sundel MH, Sgouros G. A nephron-based model of the kidneys for macro-to-micro α-particle dosimetry. Phys Med Biol 2012; 57:4403-24. [PMID: 22705986 DOI: 10.1088/0031-9155/57/13/4403] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Targeted α-particle therapy is a promising treatment modality for cancer. Due to the short path-length of α-particles, the potential efficacy and toxicity of these agents is best evaluated by microscale dosimetry calculations instead of whole-organ, absorbed fraction-based dosimetry. Yet time-integrated activity (TIA), the necessary input for dosimetry, can still only be quantified reliably at the organ or macroscopic level. We describe a nephron- and cellular-based kidney dosimetry model for α-particle radiopharmaceutical therapy, more suited to the short range and high linear energy transfer of α-particle emitters, which takes as input kidney or cortex TIA and through a macro to micro model-based methodology assigns TIA to micro-level kidney substructures. We apply a geometrical model to provide nephron-level S-values for a range of isotopes allowing for pre-clinical and clinical applications according to the medical internal radiation dosimetry (MIRD) schema. We assume that the relationship between whole-organ TIA and TIA apportioned to microscale substructures as measured in an appropriate pre-clinical mammalian model also applies to the human. In both, the pre-clinical and the human model, microscale substructures are described as a collection of simple geometrical shapes akin to those used in the Cristy-Eckerman phantoms for normal organs. Anatomical parameters are taken from the literature for a human model, while murine parameters are measured ex vivo. The murine histological slides also provide the data for volume of occupancy of the different compartments of the nephron in the kidney: glomerulus versus proximal tubule versus distal tubule. Monte Carlo simulations are run with activity placed in the different nephron compartments for several α-particle emitters currently under investigation in radiopharmaceutical therapy. The S-values were calculated for the α-emitters and their descendants between the different nephron compartments for both the human and murine models. The renal cortex and medulla S-values were also calculated and the results compared to traditional absorbed fraction calculations. The nephron model enables a more optimal implementation of treatment and is a critical step in understanding toxicity for human translation of targeted α-particle therapy. The S-values established here will enable a MIRD-type application of α-particle dosimetry for α-emitters, i.e. measuring the TIA in the kidney (or renal cortex) will provide meaningful and accurate nephron-level dosimetry.
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Affiliation(s)
- Robert F Hobbs
- Department of Radiology, Johns Hopkins University, Baltimore MD, USA.
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Davidson JD, Wiacek RJ, Burton S, Li XS, Fryxell GE, Addleman RS, Yantasee W, Sangvanich T, Pattamakomsan K. Improved deposition and deprotection of silane tethered 3,4 hydroxypyridinone (HOPO) ligands on functionalized nanoporous silica. INORG CHEM COMMUN 2012; 18:92-96. [PMID: 22942668 PMCID: PMC3430465 DOI: 10.1016/j.inoche.2012.01.025] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Abstract
An improved synthesis of a 3,4 hydroxypyridinone (HOPO) functionalized mesoporous silica is described. Higher 3,4-HOPO monolayer ligand loadings have been achieved, resulting in better performance. Performance improvements were demonstrated with the capture of U(VI) from human blood, plasma and filtered river water.
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Affiliation(s)
- Joseph D. Davidson
- Applied Materials Science Group, Pacific Northwest National Laboratory, PO Box 999, Richland, WA 99352, USA
| | - Robert J. Wiacek
- Applied Materials Science Group, Pacific Northwest National Laboratory, PO Box 999, Richland, WA 99352, USA
| | - Sarah Burton
- Applied Materials Science Group, Pacific Northwest National Laboratory, PO Box 999, Richland, WA 99352, USA
| | - Xiaohong S. Li
- Applied Materials Science Group, Pacific Northwest National Laboratory, PO Box 999, Richland, WA 99352, USA
| | - Glen E. Fryxell
- Applied Materials Science Group, Pacific Northwest National Laboratory, PO Box 999, Richland, WA 99352, USA
| | - R. Shane Addleman
- Applied Materials Science Group, Pacific Northwest National Laboratory, PO Box 999, Richland, WA 99352, USA
| | - Wassana Yantasee
- Department of Biomedical Engineering, OHSU School of Medicine, Portland, Oregon 97239, USA
| | - Thanapon Sangvanich
- Department of Biomedical Engineering, OHSU School of Medicine, Portland, Oregon 97239, USA
| | - Kanda Pattamakomsan
- Department of Biomedical Engineering, OHSU School of Medicine, Portland, Oregon 97239, USA
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Lazarov E, Arazi L, Efrati M, Cooks T, Schmidt M, Keisari Y, Kelson I. ComparativeIn VitroMicrodosimetric Study of Murine- and Human-Derived Cancer Cells Exposed to Alpha Particles. Radiat Res 2012; 177:280-7. [DOI: 10.1667/rr2664.1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Horev-Drori G, Cooks T, Bittan H, Lazarov E, Schmidt M, Arazi L, Efrati M, Kelson I, Keisari Y. Local control of experimental malignant pancreatic tumors by treatment with a combination of chemotherapy and intratumoral 224radium-loaded wires releasing alpha-emitting atoms. Transl Res 2012; 159:32-41. [PMID: 22153808 DOI: 10.1016/j.trsl.2011.08.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2011] [Revised: 08/24/2011] [Accepted: 08/27/2011] [Indexed: 12/21/2022]
Abstract
We developed (224)Ra-loaded wires that when inserted into solid tumors, release radioactive atoms that spread in the tumor and irradiate it effectively with alpha particles (diffusing alpha-emitters radiation therapy [DaRT]). In this study, we tested the ability of intratumoral (224)Ra-loaded wires to control the local growth of pancreatic tumors and the enhancement of this effect by chemotherapy. Pancreatic mouse tumors (Panc02) were treated with (224)Ra-loaded wire(s) with or without gemcitabine. The tumor size and survival were monitored, and autoradiography was performed to evaluate the spread of radioactive atoms inside the tumor. Mouse and human pancreatic cancer cells, irradiated in vitro by alpha particles with or without chemotherapy, were evaluated for cell growth inhibition. The insertion of (224)Ra-loaded wires into pancreatic tumors in combination with gemcitabine achieved significant local control and was superior to each treatment alone. A dosimetric analysis showed the spread of radioactive atoms in the tumor around the wires. Alpha particles combined with gemcitabine or 5-FU killed mouse and human cells in vitro better than each treatment alone. DaRT in combination with gemcitabine was proven effective against pancreatic tumors in vivo and in vitro, and the process may be applicable as a palliative treatment for patients with pancreatic cancer.
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Affiliation(s)
- Galit Horev-Drori
- Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
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