1
|
Liubchenko G, Böning G, Zacherl M, Rumiantcev M, Unterrainer LM, Gildehaus FJ, Brendel M, Resch S, Bartenstein P, Ziegler SI, Delker A. Image-based dosimetry for [ 225Ac]Ac-PSMA-I&T therapy and the effect of daughter-specific pharmacokinetics. Eur J Nucl Med Mol Imaging 2024; 51:2504-2514. [PMID: 38512484 PMCID: PMC11178588 DOI: 10.1007/s00259-024-06681-2] [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: 09/29/2023] [Accepted: 03/10/2024] [Indexed: 03/23/2024]
Abstract
PURPOSE Although 221Fr and 213Bi have sufficient gamma emission probabilities, quantitative SPECT after [225Ac]Ac-PSMA-I&T therapy remains challenging due to low therapeutic activities. Furthermore, 221Fr and 213Bi may underlie a different pharmacokinetics due to alpha recoil. We conducted a quantitative SPECT study and a urine analysis to investigate the pharmacokinetics of 221Fr and 213Bi and the impact on image-based lesion and kidney dosimetry. METHODS Five patients (7.7 ± 0.2 MBq [225Ac]Ac-PSMA-I&T) underwent an abdominal SPECT/CT (1 h) at 24 and 48 h (Siemens Symbia T2, high-energy collimator, 440 keV/218 keV (width 20%), 78 keV (width 50%)). Quantitative SPECT was reconstructed using MAP-EM with attenuation and transmission-dependent scatter corrections and resolution modelling. Time-activity curves for kidneys (CT-based) and lesions (80% isocontour 24 h) were fitted mono-exponentially. Urine samples collected along with each SPECT/CT were measured in a gamma counter until secular equilibrium was reached. RESULTS Mean kidney and lesion effective half-lives were as follows: 213Bi, 27 ± 6/38 ± 10 h; 221Fr, 24 ± 6/38 ± 11 h; 78 keV, 23 ± 7/39 ± 13 h. The 213Bi-to-221Fr kidney SUV ratio increased by an average of 9% from 24 to 48 h. Urine analysis revealed an increasing 213Bi-to-225Ac ratio (24 h, 0.98 ± 0.15; 48 h, 1.08 ± 0.09). Mean kidney and lesion absorbed doses were 0.17 ± 0.06 and 0.36 ± 0.1 Sv RBE = 5 /MBq using 221Fr and 213Bi SPECT images, compared to 0.16 ± 0.05/0.18 ± 0.06 and 0.36 ± 0.1/0.38 ± 0.1 Sv RBE = 5 /MBq considering either the 221Fr or 213Bi SPECT. CONCLUSION SPECT/CT imaging and urine analysis showed minor differences of up to 10% in the daughter-specific pharmacokinetics. These variances had a minimal impact on the lesion and kidney dosimetry which remained within 8%.
Collapse
Affiliation(s)
- Grigory Liubchenko
- Department of Nuclear Medicine, LMU University Hospital, LMU Munich, Marchioninstrasse 15, 81377, Munich, Germany.
| | - Guido Böning
- Department of Nuclear Medicine, LMU University Hospital, LMU Munich, Marchioninstrasse 15, 81377, Munich, Germany
| | - Mathias Zacherl
- Department of Nuclear Medicine, LMU University Hospital, LMU Munich, Marchioninstrasse 15, 81377, Munich, Germany
| | - Mikhail Rumiantcev
- Department of Nuclear Medicine, LMU University Hospital, LMU Munich, Marchioninstrasse 15, 81377, Munich, Germany
| | - Lena M Unterrainer
- Department of Nuclear Medicine, LMU University Hospital, LMU Munich, Marchioninstrasse 15, 81377, Munich, Germany
- Ahmanson Translational Theranostics Division, Department of Molecular and Medical Pharmacology, University of California Los Angeles, Los Angeles, CA, USA
| | - Franz Josef Gildehaus
- Department of Nuclear Medicine, LMU University Hospital, LMU Munich, Marchioninstrasse 15, 81377, Munich, Germany
| | - Matthias Brendel
- Department of Nuclear Medicine, LMU University Hospital, LMU Munich, Marchioninstrasse 15, 81377, Munich, Germany
- SyNergy, University of Munich, Munich, Germany
- DZNE - German Center for Neurodegenerative Diseases, Munich, Germany
| | - Sandra Resch
- Department of Nuclear Medicine, LMU University Hospital, LMU Munich, Marchioninstrasse 15, 81377, Munich, Germany
| | - Peter Bartenstein
- Department of Nuclear Medicine, LMU University Hospital, LMU Munich, Marchioninstrasse 15, 81377, Munich, Germany
| | - Sibylle I Ziegler
- Department of Nuclear Medicine, LMU University Hospital, LMU Munich, Marchioninstrasse 15, 81377, Munich, Germany
| | - Astrid Delker
- Department of Nuclear Medicine, LMU University Hospital, LMU Munich, Marchioninstrasse 15, 81377, Munich, Germany
| |
Collapse
|
2
|
Schatz CA, Zitzmann-Kolbe S, Moen I, Klotz M, Nair S, Stargard S, Bjerke RM, Wickstrøm Biseth K, Feng YZ, Indrevoll B, Cruciani V, Karlsson J, Haendler B, Nielsen CH, Alfsen MZ, Hammer S, Hennekes H, Cuthbertson A, Hagemann UB, Larsen Å. Preclinical Efficacy of a PSMA-Targeted Actinium-225 Conjugate (225Ac-Macropa-Pelgifatamab): A Targeted Alpha Therapy for Prostate Cancer. Clin Cancer Res 2024; 30:2531-2544. [PMID: 38593212 DOI: 10.1158/1078-0432.ccr-23-3746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 02/07/2024] [Accepted: 04/03/2024] [Indexed: 04/11/2024]
Abstract
PURPOSE Initially, prostate cancer responds to hormone therapy, but eventually resistance develops. Beta emitter-based prostate-specific membrane antigen (PSMA)-targeted radionuclide therapy is approved for the treatment of metastatic castration-resistant prostate cancer. Here we introduce a targeted alpha therapy (TAT) consisting of the PSMA antibody pelgifatamab covalently linked to a macropa chelator and labeled with actinium-225 and compare its efficacy and tolerability with other TATs. EXPERIMENTAL DESIGN The in vitro characteristics and in vivo biodistribution, antitumor efficacy, and tolerability of 225Ac-macropa-pelgifatamab (225Ac-pelgi) and other TATs were investigated in cell line- and patient-derived prostate cancer xenograft models. The antitumor efficacy of 225Ac-pelgi was also investigated in combination with the androgen receptor inhibitor darolutamide. RESULTS Actinium-225-labeling of 225Ac-pelgi was efficient already at room temperature. Potent in vitro cytotoxicity was seen in PSMA-expressing (LNCaP, MDA-PCa-2b, and C4-2) but not in PSMA-negative (PC-3 and DU-145) cell lines. High tumor accumulation was seen for both 225Ac-pelgi and 225Ac-DOTA-pelgi in the MDA-PCa-2b xenograft model. In the C4-2 xenograft model, 225Ac-pelgi showed enhanced antitumor efficacy with a T/Cvolume (treatment/control) ratio of 0.10 compared with 225Ac-DOTA-pelgi, 225Ac-DOTA-J591, and 227Th-HOPO-pelgifatamab (227Th-pelgi; all at 300 kBq/kg) with T/Cvolume ratios of 0.37, 0.39, and 0.33, respectively. 225Ac-pelgi was less myelosuppressive than 227Th-pelgi. 225Ac-pelgi showed dose-dependent treatment efficacy in the patient-derived KuCaP-1 model and strong combination potential with darolutamide in both cell line- (22Rv1) and patient-derived (ST1273) xenograft models. CONCLUSIONS These results provide a strong rationale to investigate 225Ac-pelgi in patients with prostate cancer. A clinical phase I study has been initiated (NCT06052306).
Collapse
|
3
|
Hull A, Hsieh W, Borysenko A, Tieu W, Bartholomeusz D, Bezak E. Development of [ 225Ac]Ac-DOTA-C595 as radioimmunotherapy of pancreatic cancer: in vitro evaluation, dosimetric assessment and detector calibration. EJNMMI Radiopharm Chem 2023; 8:22. [PMID: 37679594 PMCID: PMC10484829 DOI: 10.1186/s41181-023-00209-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 08/28/2023] [Indexed: 09/09/2023] Open
Abstract
BACKGROUND Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy which may benefit from radioimmunotherapy. Previously, [177Lu]Lu-DOTA-C595 has been developed as a beta-emitting radioimmunoconjugate to target cancer-specific mucin 1 epitopes (MUC1-CE) overexpressed on PDAC. However, the therapeutic effect may be enhanced by using an alpha-emitting radionuclide such as Actinium-225 (Ac-225). The short range and high linear energy transfer of alpha particles provides dense cellular damage and can overcome typical barriers related to PDAC treatment such as hypoxia. Despite the added cytotoxicity of alpha-emitters, their clinical implementation can be complicated by their complex decay chains, recoil energy and short-range impeding radiation detection. In this study, we developed and evaluated [225Ac]Ac-DOTA-C595 as an alpha-emitting radioimmunotherapy against PDAC using a series of in vitro experiments and conducted a preliminary dosimetric assessment and cross-calibration of detectors for the clinical implementation of Ac-225. RESULTS Cell binding and internalisation of [225Ac]Ac-DOTA-C595 was rapid and greatest in cells with strong MUC1-CE expression. Over 99% of PDAC cells had positive yH2AX expression within 1 h of [225Ac]Ac-DOTA-C595 exposure, suggesting a high level of DNA damage. Clonogenic assays further illustrated the cytotoxicity of [225Ac]Ac-DOTA-C595 in a concentration-dependent manner. At low concentrations of [225Ac]Ac-DOTA-C595, cells with strong MUC1-CE expression had lower cell survival than cells with weak MUC1-CE expression, yet survival was similar between cell lines at high concentrations irrespective of MUC1-CE expression. A dosimetric assessment was performed to estimate the dose-rate of 1 kBq of [225Ac]Ac-DOTA-C595 with consideration to alpha particles. Total absorption of 1 kBq of Ac-225 was estimated to provide a dose rate of 17.5 mGy/h, confirmed via both detector measurements and calculations. CONCLUSION [225Ac]Ac-DOTA-C595 was shown to target and induce a therapeutic effect in MUC1-CE expressing PDAC cells.
Collapse
Affiliation(s)
- Ashleigh Hull
- Allied Health and Human Performance Academic Unit, University of South Australia, City East Campus, Cnr North Tce and Frome Road, Adelaide, SA, 5001, Australia.
- Department of PET, Nuclear Medicine & Bone Densitometry, Royal Adelaide Hospital, SA Medical Imaging, Adelaide, SA, 5000, Australia.
| | - William Hsieh
- Allied Health and Human Performance Academic Unit, University of South Australia, City East Campus, Cnr North Tce and Frome Road, Adelaide, SA, 5001, Australia
- Department of PET, Nuclear Medicine & Bone Densitometry, Royal Adelaide Hospital, SA Medical Imaging, Adelaide, SA, 5000, Australia
| | - Artem Borysenko
- Radiation Protection Branch, South Australian Environment Protection Authority, Adelaide, SA, 5000, Australia
| | - William Tieu
- School of Physical Sciences, The University of Adelaide, Adelaide, SA, 5000, Australia
| | - Dylan Bartholomeusz
- Department of PET, Nuclear Medicine & Bone Densitometry, Royal Adelaide Hospital, SA Medical Imaging, Adelaide, SA, 5000, Australia
- Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5000, Australia
| | - Eva Bezak
- Allied Health and Human Performance Academic Unit, University of South Australia, City East Campus, Cnr North Tce and Frome Road, Adelaide, SA, 5001, Australia
- School of Physical Sciences, The University of Adelaide, Adelaide, SA, 5000, Australia
| |
Collapse
|
4
|
Koniar H, Miller C, Rahmim A, Schaffer P, Uribe C. A GATE simulation study for dosimetry in cancer cell and micrometastasis from the 225Ac decay chain. EJNMMI Phys 2023; 10:46. [PMID: 37525027 PMCID: PMC10390455 DOI: 10.1186/s40658-023-00564-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Accepted: 07/24/2023] [Indexed: 08/02/2023] Open
Abstract
BACKGROUND Radiopharmaceutical therapy (RPT) with alpha-emitting radionuclides has shown great promise in treating metastatic cancers. The successive emission of four alpha particles in the 225Ac decay chain leads to highly targeted and effective cancer cell death. Quantifying cellular dosimetry for 225Ac RPT is essential for predicting cell survival and therapeutic success. However, the leading assumption that all 225Ac progeny remain localized at their target sites likely overestimates the absorbed dose to cancer cells. To address limitations in existing semi-analytic approaches, this work evaluates S-values for 225Ac's progeny radionuclides with GATE Monte Carlo simulations. METHODS The cellular geometries considered were an individual cell (10 µm diameter with a nucleus of 8 µm diameter) and a cluster of cells (micrometastasis) with radionuclides localized in four subcellular regions: cell membrane, cytoplasm, nucleus, or whole cell. The absorbed dose to the cell nucleus was scored, and self- and cross-dose S-values were derived. We also evaluated the total absorbed dose with various degrees of radiopharmaceutical internalization and retention of the progeny radionuclides 221Fr (t1/2 = 4.80 m) and 213Bi (t1/2 = 45.6 m). RESULTS For the cumulative 225Ac decay chain, our self- and cross-dose nuclear S-values were both in good agreement with S-values published by MIRDcell, with per cent differences ranging from - 2.7 to - 8.7% for the various radionuclide source locations. Source location had greater effects on self-dose S-values than the intercellular cross-dose S-values. Cumulative 225Ac decay chain self-dose S-values increased from 0.167 to 0.364 GyBq-1 s-1 with radionuclide internalization from the cell surface into the cell. When progeny migration from the target site was modelled, the cumulative self-dose S-values to the cell nucleus decreased by up to 71% and 21% for 221Fr and 213Bi retention, respectively. CONCLUSIONS Our GATE Monte Carlo simulations resulted in cellular S-values in agreement with existing MIRD S-values for the alpha-emitting radionuclides in the 225Ac decay chain. To obtain accurate absorbed dose estimates in 225Ac studies, accurate understanding of daughter migration is critical for optimized injected activities. Future work will investigate other novel preclinical alpha-emitting radionuclides to evaluate therapeutic potency and explore realistic cellular geometries corresponding to targeted cancer cell lines.
Collapse
Affiliation(s)
- Helena Koniar
- Life Sciences Division, TRIUMF, Vancouver, BC, Canada.
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada.
| | - Cassandra Miller
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada
- Department of Integrative Oncology, BC Cancer Research Institute, Vancouver, BC, Canada
| | - Arman Rahmim
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada
- Department of Integrative Oncology, BC Cancer Research Institute, Vancouver, BC, Canada
- Department of Radiology, University of British Columbia, Vancouver, BC, Canada
| | - Paul Schaffer
- Life Sciences Division, TRIUMF, Vancouver, BC, Canada
- Department of Radiology, University of British Columbia, Vancouver, BC, Canada
- Department of Chemistry, Simon Fraser University, Burnaby, BC, Canada
| | - Carlos Uribe
- Department of Radiology, University of British Columbia, Vancouver, BC, Canada
- Functional Imaging, BC Cancer, Vancouver, BC, Canada
| |
Collapse
|
5
|
Rubira L, Deshayes E, Santoro L, Kotzki PO, Fersing C. 225Ac-Labeled Somatostatin Analogs in the Management of Neuroendocrine Tumors: From Radiochemistry to Clinic. Pharmaceutics 2023; 15:pharmaceutics15041051. [PMID: 37111537 PMCID: PMC10146019 DOI: 10.3390/pharmaceutics15041051] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 03/18/2023] [Accepted: 03/22/2023] [Indexed: 04/29/2023] Open
Abstract
The widespread use of peptide receptor radionuclide therapy (PRRT) represents a major therapeutic breakthrough in nuclear medicine, particularly since the introduction of 177Lu-radiolabeled somatostatin analogs. These radiopharmaceuticals have especially improved progression-free survival and quality of life in patients with inoperable metastatic gastroenteropancreatic neuroendocrine tumors expressing somatostatin receptors. In the case of aggressive or resistant disease, the use of somatostatin derivatives radiolabeled with an alpha-emitter could provide a promising alternative. Among the currently available alpha-emitting radioelements, actinium-225 has emerged as the most suitable candidate, especially regarding its physical and radiochemical properties. Nevertheless, preclinical and clinical studies on these radiopharmaceuticals are still few and heterogeneous, despite the growing momentum for their future use on a larger scale. In this context, this report provides a comprehensive and extensive overview of the development of 225Ac-labeled somatostatin analogs; particular emphasis is placed on the challenges associated with the production of 225Ac, its physical and radiochemical properties, as well as the place of 225Ac-DOTATOC and 225Ac-DOTATATE in the management of patients with advanced metastatic neuroendocrine tumors.
Collapse
Affiliation(s)
- Léa Rubira
- Nuclear Medicine Department, Institut Régional du Cancer de Montpellier (ICM), University Montpellier, 34090 Montpellier, France
| | - Emmanuel Deshayes
- Nuclear Medicine Department, Institut Régional du Cancer de Montpellier (ICM), University Montpellier, 34090 Montpellier, France
- Institut de Recherche en Cancérologie de Montpellier (IRCM), INSERM U1194, University Montpellier, Institut Régional du Cancer de Montpellier (ICM), 34298 Montpellier, France
| | - Lore Santoro
- Nuclear Medicine Department, Institut Régional du Cancer de Montpellier (ICM), University Montpellier, 34090 Montpellier, France
- Institut de Recherche en Cancérologie de Montpellier (IRCM), INSERM U1194, University Montpellier, Institut Régional du Cancer de Montpellier (ICM), 34298 Montpellier, France
| | - Pierre Olivier Kotzki
- Nuclear Medicine Department, Institut Régional du Cancer de Montpellier (ICM), University Montpellier, 34090 Montpellier, France
- Institut de Recherche en Cancérologie de Montpellier (IRCM), INSERM U1194, University Montpellier, Institut Régional du Cancer de Montpellier (ICM), 34298 Montpellier, France
| | - Cyril Fersing
- Nuclear Medicine Department, Institut Régional du Cancer de Montpellier (ICM), University Montpellier, 34090 Montpellier, France
- IBMM, University Montpellier, CNRS, ENSCM, 34293 Montpellier, France
| |
Collapse
|
6
|
Kelly JM, Amor-Coarasa A, Sweeney E, Wilson JJ, Causey PW, Babich JW. A suitable time point for quantifying the radiochemical purity of 225Ac-labeled radiopharmaceuticals. EJNMMI Radiopharm Chem 2021; 6:38. [PMID: 34928478 PMCID: PMC8688611 DOI: 10.1186/s41181-021-00151-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 08/27/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND As 225Ac-labeled radiopharmaceuticals continue to show promise as targeted alpha therapeutics, there is a growing need to standardize quality control (QC) testing procedures. The determination of radiochemical purity (RCP) is an essential QC test. A significant obstacle to RCP testing is the disruption of the secular equilibrium between actinium-225 and its daughter radionuclides during labeling and QC testing. In order to accelerate translation of actinium-225 targeted alpha therapy, we aimed to determine the earliest time point at which the RCP of an 225Ac-labeled radiopharmaceutical can be accurately quantified. RESULTS Six ligands were conjugated to macrocyclic metal chelators and labeled with actinium-225 under conditions designed to generate diverse incorporation yields. RCP was determined by radio thin layer chromatography (radioTLC) followed by exposure of the TLC plate on a phosphor screen either 0.5, 2, 3.5, 5, 6.5, or 26 h after the plate was developed. The dataset was used to create models for predicting the true RCP for any pre-equilibrium measurement taken at an early time point. The 585 TLC measurements span RCP values of 1.8-99.5%. The statistical model created from these data predicted an independent data set with high accuracy. Predictions made at 0.5 h are more uncertain than predictions made at later time points. This is primarily due to the decay of bismuth-213. A measurement of RCP > 90% at 2 h predicts a true RCP > 97% and guarantees that RCP will exceed 90% after secular equilibrium is reached. These findings were independently validated using NaI(Tl) scintillation counting and high resolution gamma spectroscopy on a smaller set of samples with 10% ≤ RCP ≤ 100%. CONCLUSIONS RCP of 225Ac-labeled radiopharmaceuticals can be quantified with acceptable accuracy at least 2 h after radioTLC using various methods of quantifying particle emissions. This time point best balances the need to accurately quantify RCP with the need to safely release the batch as quickly as possible.
Collapse
Affiliation(s)
- James M Kelly
- Department of Radiology, Molecular Imaging Innovations Institute (MI3), Weill Cornell Medicine, New York, NY, 10065, USA
| | | | - Elizabeth Sweeney
- Division of Biostatistics, Department of Population Health Sciences, Weill Cornell Medicine, New York, NY, 10065, USA
| | - Justin J Wilson
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, 14853, USA
| | | | - John W Babich
- Department of Radiology, Molecular Imaging Innovations Institute (MI3), Weill Cornell Medicine, New York, NY, 10065, USA.
- Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, New York, NY, 10065, USA.
- Department of Radiology, Citigroup Biomedical Imaging Center, Weill Cornell Medicine, Belfer Research Building, Room 1600, 413 E 69th St, New York, NY, 10021, USA.
| |
Collapse
|
7
|
Koziorowski J, Ballinger J. Theragnostic radionuclides: a clinical perspective. THE QUARTERLY JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING : OFFICIAL PUBLICATION OF THE ITALIAN ASSOCIATION OF NUCLEAR MEDICINE (AIMN) [AND] THE INTERNATIONAL ASSOCIATION OF RADIOPHARMACOLOGY (IAR), [AND] SECTION OF THE SOCIETY OF... 2021; 65:306-314. [PMID: 34881851 DOI: 10.23736/s1824-4785.21.03424-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The concept of theragnostics goes back to the earliest days of nuclear medicine, with [123I/131I]iodide in thyroid disease and [123I/131I]MIBG in phaeochromocytoma being examples in long-term use. However, in recent years there has been a great expansion in the application of theragnostics, beginning with [68Ga/177Lu]-labelled somatostatin peptides for evaluation and treatment of neuroendocrine tumors. We are currently seeing the rapid development of [68Ga/177Lu]PSMA theragnostics in metastatic prostate cancer. While these applications are very promising, there are a number of practicalities which must be addressed in the development and introduction of novel theragnostics. The physical half-lives of the diagnostic and therapeutic radionuclides must be appropriate for imaging and delivery of targeted cell killing, respectively. The types of radioactive emissions are critical; beta particles can traverse several millimeters but also risk damaging non-target tissues, while alpha particles deliver their energy over a much shorter path length, a few cell diameters, and must be more directly targeted. It must be practical to produce the therapeutic radionuclide and the final radiopharmaceutical and deliver them to the final user within an appropriate time-frame determined by half-life and stability. The biodistribution of the agent must demonstrate adequate accumulation and retention in the target tissue with clearance from adjacent and/or radio-sensitive normal tissues. The commercial success of recently introduced theragnostics suggests a rosy future for personalized medicine.
Collapse
|
8
|
Tafreshi NK, Pandya DN, Tichacek CJ, Budzevich MM, Wang Z, Reff JN, Engelman RW, Boulware DC, Chiappori AA, Strosberg JR, Ji H, Wadas TJ, El-Haddad G, Morse DL. Preclinical evaluation of [ 225Ac]Ac-DOTA-TATE for treatment of lung neuroendocrine neoplasms. Eur J Nucl Med Mol Imaging 2021; 48:3408-3421. [PMID: 33772332 DOI: 10.1007/s00259-021-05315-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 03/10/2021] [Indexed: 12/14/2022]
Abstract
PURPOSE There is significant interest in the development of targeted alpha-particle therapies (TATs) for treatment of solid tumors. The metal chelator-peptide conjugate, DOTA-TATE, loaded with the β-particle emitting radionuclide 177Lu ([177Lu]Lu-DOTA-TATE) is now standard care for neuroendocrine tumors that express the somatostatin receptor 2 (SSTR2) target. A recent clinical study demonstrated efficacy of the corresponding [225Ac]Ac-DOTA-TATE in patients that were refractory to [177Lu]Lu-DOTA-TATE. Herein, we report the radiosynthesis, toxicity, biodistribution (BD), radiation dosimetry (RD), and efficacy of [225Ac]Ac-DOTA-TATE in small animal models of lung neuroendocrine neoplasms (NENs). METHODS [225Ac]Ac-DOTA-TATE was synthesized and characterized for radiochemical yield, purity and stability. Non-tumor-bearing BALB/c mice were tested for toxicity and BD. Efficacy was determined by single intravenous injection of [225Ac]Ac-DOTA-TATE into SCID mice-bearing human SSTR2 positive H727 and H69 lung NENs. RD was calculated using the BD data. RESULTS [225Ac]Ac-DOTA-TATE was synthesized with 98% yield, 99.8% purity, and displayed 97% stability after 2 days incubation in human serum at 37 °C. All animals in the toxicity study appeared healthy 5 months post injection with no indications of toxicity, except that animals that received ≥111 kBq of [225Ac]Ac-DOTA-TATE had chronic progressive nephropathy. BD studies revealed that the primary route of elimination is by the renal route. RD calculations determined pharmacokinetics parameters and absorbed α-emission dosages from 225Ac and its daughters. For both tumor models, a significant tumor growth delay and time to experimental endpoint were observed following a single administration of [225Ac]Ac-DOTA-TATE relative to controls. CONCLUSIONS These results suggest significant potential for the clinical translation of [225Ac]Ac-DOTA-TATE for lung NENs.
Collapse
Affiliation(s)
- Narges K Tafreshi
- Department of Cancer Physiology, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL, USA
| | - Darpan N Pandya
- Department of Radiology, University of Iowa Health Care, Iowa City, IA, USA
| | - Christopher J Tichacek
- Department of Radiation Oncology, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL, USA
- Department of Physics and Oncologic Sciences, University of South Florida, Tampa, FL, USA
- Oncologic Sciences, University of South Florida, Tampa, FL, USA
| | | | - Zhen Wang
- Department of Drug Discovery, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL, USA
| | - Jordan N Reff
- Department of Cancer Physiology, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL, USA
| | - Robert W Engelman
- Department of Pediatrics, Pathology & Cell Biology, University of South Florida, Tampa, FL, USA
| | - David C Boulware
- Biostatistics and Bioinformatics Shared Resource, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL, USA
| | - Alberto A Chiappori
- Department of Thoracic Oncology, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL, USA
| | - Jonathan R Strosberg
- Gastrointestinal Oncology, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL, USA
| | - Haitao Ji
- Department of Drug Discovery, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL, USA
| | - Thaddeus J Wadas
- Department of Radiology, University of Iowa Health Care, Iowa City, IA, USA
| | - Ghassan El-Haddad
- Diagnostic Imaging and Interventional Radiology, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL, USA.
| | - David L Morse
- Department of Cancer Physiology, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL, USA.
- Department of Physics and Oncologic Sciences, University of South Florida, Tampa, FL, USA.
- Oncologic Sciences, University of South Florida, Tampa, FL, USA.
- Small Animal Imaging Laboratory Shared Resource, Tampa, FL, USA.
| |
Collapse
|
9
|
Atomic Nanogenerators in Targeted Alpha Therapies: Curie's Legacy in Modern Cancer Management. Pharmaceuticals (Basel) 2020; 13:ph13040076. [PMID: 32340103 PMCID: PMC7243103 DOI: 10.3390/ph13040076] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 04/17/2020] [Accepted: 04/21/2020] [Indexed: 12/12/2022] Open
Abstract
Atomic in vivo nanogenerators such as actinium-225, thorium-227, and radium-223 are of increasing interest and importance in the treatment of patients with metastatic cancer diseases. This is due to their peculiar physical, chemical, and biological characteristics, leading to astonishing responses in otherwise resistant patients. Nevertheless, there are still a few obstacles and hurdles to be overcome that hamper the broader utilization in the clinical setting. Next to the limited supply and relatively high costs, the in vivo complex stability and the fate of the recoiling daughter radionuclides are substantial problems that need to be solved. In radiobiology, the mechanisms underlying treatment efficiency, possible resistance mechanisms, and late side effect occurrence are still far from being understood and need to be unraveled. In this review, the current knowledge on the scientific and clinical background of targeted alpha therapies is summarized. Furthermore, open issues and novel approaches with a focus on the future perspective are discussed. Once these are unraveled, targeted alpha therapies with atomic in vivo nanogenerators can be tailored to suit the needs of each patient when applying careful risk stratification and combination therapies. They have the potential to become one of the major treatment pillars in modern cancer management.
Collapse
|