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Current Radiopharmaceuticals 2018Recent reports of the remarkable therapeutic efficacy of 225Ac-labeled PSMA- 617 for therapy of metastatic castration-resistant prostate cancer have underlined the... (Review)
Review
BACKGROUND
Recent reports of the remarkable therapeutic efficacy of 225Ac-labeled PSMA- 617 for therapy of metastatic castration-resistant prostate cancer have underlined the clinical potential of targeted alpha therapy.
OBJECTIVE AND CONCLUSION
This review describes methods for the production of 225Ac and its daughter nuclide 213Bi and summarizes the current clinical experience with both alpha emitters with particular focus on recent studies of targeted alpha therapy of bladder cancer, brain tumors, neuroendocrine tumors and prostate cancer.
Topics: Actinium; Alpha Particles; Bismuth; Clinical Trials as Topic; Humans; Neoplasms; Radiochemistry; Radioimmunotherapy; Radioisotopes; Radiopharmaceuticals
PubMed: 29732998
DOI: 10.2174/1874471011666180502104524 -
International Journal of Molecular... Jul 2023Radiopharmaceuticals are rapidly developing as a field, with the successful use of targeted beta emitters in neuroendocrine tumors and prostate cancer serving as... (Review)
Review
Radiopharmaceuticals are rapidly developing as a field, with the successful use of targeted beta emitters in neuroendocrine tumors and prostate cancer serving as catalysts. Targeted alpha emitters are in current development for several potential oncologic indications. Herein, we review the three most prevalently studied conjugated/chelated alpha emitters (actinium, lead, and astatine) and focus on contemporary clinical trials in an effort to more fully appreciate the breadth of the current evaluation. Phase I trials targeting multiple diseases are now underway, and at least one phase III trial (in selected neuroendocrine cancers) is currently in the initial stages of recruitment. Combination trials are now also emerging as alpha emitters are integrated with other therapies in an effort to create solutions for those with advanced cancers. Despite the promise of targeted alpha therapies, many challenges remain. These challenges include the development of reliable supply chains, the need for a better understanding of the relationships between administered dose and absorbed dose in both tissue and tumor and how that predicts outcomes, and the incomplete understanding of potential long-term deleterious effects of the alpha emitters. Progress on multiple fronts is necessary to bring the potential of targeted alpha therapies into the clinic.
Topics: Humans; Male; Alpha Particles; Prostatic Neoplasms; Radiopharmaceuticals; Clinical Trials as Topic
PubMed: 37511386
DOI: 10.3390/ijms241411626 -
Journal of Nuclear Medicine : Official... Dec 2016Prostate-specific membrane antigen (PSMA) is a promising target in prostate cancer. Recently, we started the first-in-human treatment with an α-radionuclide-labeled...
UNLABELLED
Prostate-specific membrane antigen (PSMA) is a promising target in prostate cancer. Recently, we started the first-in-human treatment with an α-radionuclide-labeled PSMA ligand. Although the case series is still ongoing, we here report in advance about two patients in highly challenging clinical situations who showed a complete response to Ac-PSMA-617 therapy.
METHODS
Ga-PSMA-11 PET/CT validated the presence of the PSMA-positive tumor phenotype. A 100-kBq activity of Ac-PSMA-617 per kilogram of body weight was administered bimonthly. Prostate-specific antigen response and hematologic toxicity were measured at least every 4 wk. Restaging was performed with Ga-PSMA-11 PET/CT.
RESULTS
Both patients experienced a prostate-specific antigen decline to below the measurable level and showed a complete response on imaging. No relevant hematologic toxicity was observed. Xerostomia was the only mentionable clinical side effect.
CONCLUSION
Targeted α-therapy with Ac-PSMA-617, although still experimental, obviously has strong potential to significantly benefit advanced-stage prostate cancer patients.
Topics: Actinium; Alpha Particles; Antigens, Surface; Beta Particles; Dipeptides; Glutamate Carboxypeptidase II; Heterocyclic Compounds, 1-Ring; Humans; Lutetium; Male; Neoplasm Metastasis; Positron Emission Tomography Computed Tomography; Prostate-Specific Antigen; Prostatic Neoplasms, Castration-Resistant; Radioisotopes
PubMed: 27390158
DOI: 10.2967/jnumed.116.178673 -
Cancer Biotherapy & Radiopharmaceuticals Aug 2020
Topics: Alpha Particles; Antibodies, Monoclonal; Humans; Molecular Targeted Therapy; Neoplasms; Radiation Oncology; Radioisotopes; Radiopharmaceuticals; Radium
PubMed: 32503377
DOI: 10.1089/cbr.2020.29008.mbr -
Clinical Cancer Research : An Official... May 2023Radiopharmaceutical therapy is changing the standard of care in prostate cancer and other malignancies. We previously reported high CD46 expression in prostate cancer...
PURPOSE
Radiopharmaceutical therapy is changing the standard of care in prostate cancer and other malignancies. We previously reported high CD46 expression in prostate cancer and developed an antibody-drug conjugate and immunoPET agent based on the YS5 antibody, which targets a tumor-selective CD46 epitope. Here, we present the preparation, preclinical efficacy, and toxicity evaluation of [225Ac]DOTA-YS5, a radioimmunotherapy agent based on the YS5 antibody.
EXPERIMENTAL DESIGN
[225Ac]DOTA-YS5 was developed, and its therapeutic efficiency was tested on cell-derived (22Rv1, DU145), and patient-derived (LTL-545, LTL484) prostate cancer xenograft models. Biodistribution studies were carried out on 22Rv1 tumor xenograft models to confirm the targeting efficacy. Toxicity analysis of the [225Ac]DOTA-YS5 was carried out on nu/nu mice to study short-term (acute) and long-term (chronic) toxicity.
RESULTS
Biodistribution study shows that [225Ac]DOTA-YS5 agent delivers high levels of radiation to the tumor tissue (11.64% ± 1.37%ID/g, 28.58% ± 10.88%ID/g, 29.35% ± 7.76%ID/g, and 31.78% ± 5.89%ID/g at 24, 96, 168, and 408 hours, respectively), compared with the healthy organs. [225Ac]DOTA-YS5 suppressed tumor size and prolonged survival in cell line-derived and patient-derived xenograft models. Toxicity analysis revealed that the 0.5 μCi activity levels showed toxicity to the kidneys, likely due to redistribution of daughter isotope 213Bi.
CONCLUSIONS
[225Ac]DOTA-YS5 suppressed the growth of cell-derived and patient-derived xenografts, including prostate-specific membrane antigen-positive and prostate-specific membrane antigen-deficient models. Overall, this preclinical study confirms that [225Ac]DOTA-YS5 is a highly effective treatment and suggests feasibility for clinical translation of CD46-targeted radioligand therapy in prostate cancer.
Topics: Mice; Male; Animals; Humans; Radioisotopes; Actinium; Bismuth; Radioimmunotherapy; Alpha Particles; Tissue Distribution; Prostatic Neoplasms; Membrane Cofactor Protein
PubMed: 36917693
DOI: 10.1158/1078-0432.CCR-22-3291 -
PET Clinics Jul 2024Targeted radionuclide therapy (TRT) has significantly evolved from its beginnings with iodine-131 to employing carrier molecules with beta emitting isotopes like... (Review)
Review
Targeted radionuclide therapy (TRT) has significantly evolved from its beginnings with iodine-131 to employing carrier molecules with beta emitting isotopes like lutetium-177. With the success of Lu-177-DOTATATE for neuroendocrine tumors and Lu-177-PSMA-617 for prostate cancer, several other beta emitting radioisotopes, such as Cu-67 and Tb-161, are being explored for TRT. The field has also expanded into targeted alpha therapy (TAT) with agents like radium-223 for bone metastases in prostate cancer, and several other alpha emitter radioisotopes with carrier molecules, such as Ac-225, and Pb-212 under clinical trials. Despite these advancements, the scope of TRT in treating diverse solid tumors and integration with other therapies like immunotherapy remains under investigation. The success of antibody-drug conjugates further complements treatments with TRT, though challenges in treatment optimization continue.
Topics: Humans; Beta Particles; Alpha Particles; Radioisotopes; Radiopharmaceuticals; Neoplasms; Prostatic Neoplasms; Male; Lutetium; Radium; Bone Neoplasms
PubMed: 38688775
DOI: 10.1016/j.cpet.2024.03.006 -
Annual Review of Biomedical Engineering Jun 2018α-Particle irradiation of cancerous tissue is increasingly recognized as a potent therapeutic option. We briefly review the physics, radiobiology, and dosimetry of... (Review)
Review
α-Particle irradiation of cancerous tissue is increasingly recognized as a potent therapeutic option. We briefly review the physics, radiobiology, and dosimetry of α-particle emitters, as well as the distinguishing features that make them unique for radiopharmaceutical therapy. We also review the emerging clinical role of α-particle therapy in managing cancer and recent studies on in vitro and preclinical α-particle therapy delivered by antibodies, other small molecules, and nanometer-sized particles. In addition to their unique radiopharmaceutical characteristics, the increased availability and improved radiochemistry of α-particle radionuclides have contributed to the growing recent interest in α-particle radiotherapy. Targeted therapy strategies have presented novel possibilities for the use of α-particles in the treatment of cancer. Clinical experience has already demonstrated the safe and effective use of α-particle emitters as potent tumor-selective drugs for the treatment of leukemia and metastatic disease.
Topics: Actinium; Alpha Particles; Animals; Cell Survival; Clinical Trials as Topic; Drug Carriers; Humans; Kinetics; Leukemia; Nanomedicine; Nanoparticles; Neoplasm Metastasis; Neoplasms; Radioimmunotherapy; Radioisotopes; Radiopharmaceuticals; Radium
PubMed: 29345977
DOI: 10.1146/annurev-bioeng-062117-120931 -
Current Radiopharmaceuticals 2018The radionuclide 225Ac and its daughter 213Bi are among the most interesting alpha emitters being evaluated for incorporation into targeted therapeutic vectors. Global... (Review)
Review
BACKGROUND
The radionuclide 225Ac and its daughter 213Bi are among the most interesting alpha emitters being evaluated for incorporation into targeted therapeutic vectors. Global supply of 225Ac is presently insufficient to meet anticipated clinical demand, but the deficiency has been targeted by many research and development efforts, privately and publicly funded. From more than a decade of these endeavors, no single production technology has emerged as a complete solution. In the foreseeable future, global supply of 225Ac will continue to be sourced from a patchwork of production methods and laboratories with a range of radioisotopic purities and achievable yields.
OBJECTIVE AND CONCLUSION
This manuscript attempts to present an overview of availability sources of 225Ac and production methods by which additional supplies might be made available to the community of clinical researchers seeking their application in the treatment of human disease.
Topics: Actinium; Alpha Particles; Radiochemistry; Radionuclide Generators; Radiopharmaceuticals
PubMed: 29669509
DOI: 10.2174/1874471011666180418141357 -
Radiation and Environmental Biophysics Mar 2020At the tissue level, energy deposition in cells is determined by the microdistribution of alpha-emitting radionuclides in relation to sensitive target cells.... (Review)
Review
At the tissue level, energy deposition in cells is determined by the microdistribution of alpha-emitting radionuclides in relation to sensitive target cells. Furthermore, the highly localized energy deposition of alpha particle tracks and the limited range of alpha particles in tissue produce a highly inhomogeneous energy deposition in traversed cell nuclei. Thus, energy deposition in cell nuclei in a given tissue is characterized by the probability of alpha particle hits and, in the case of a hit, by the energy deposited there. In classical microdosimetry, the randomness of energy deposition in cellular sites is described by a stochastic quantity, the specific energy, which approximates the macroscopic dose for a sufficiently large number of energy deposition events. Typical examples of the alpha-emitting radionuclides in internal microdosimetry are radon progeny and plutonium in the lungs, plutonium and americium in bones, and radium in targeted radionuclide therapy. Several microdosimetric approaches have been proposed to relate specific energy distributions to radiobiological effects, such as hit-related concepts, LET and track length-based models, effect-specific interpretations of specific energy distributions, such as the dual radiation action theory or the hit-size effectiveness function, and finally track structure models. Since microdosimetry characterizes only the initial step of energy deposition, microdosimetric concepts are most successful in exposure situations where biological effects are dominated by energy deposition, but not by subsequently operating biological mechanisms. Indeed, the simulation of the combined action of physical and biological factors may eventually require the application of track structure models at the nanometer scale.
Topics: Alpha Particles; Animals; Bone and Bones; Humans; Lung; Radioisotopes; Radiometry
PubMed: 31863162
DOI: 10.1007/s00411-019-00826-w -
Cancer Biotherapy & Radiopharmaceuticals Aug 2020The rates of cancer incidence and mortality are increasing day by day. Although several conventional methods including surgery, chemotherapy, and radiotherapy (RT) exist... (Review)
Review
The rates of cancer incidence and mortality are increasing day by day. Although several conventional methods including surgery, chemotherapy, and radiotherapy (RT) exist for cancer treatment, they are insufficient in the eradication of all tumor tissues and have some side-effects such as narrow therapeutic index and serious side-effects to healthy tissues. Moreover, it may probably recur in time due to the survival and spreading of cancerous cells or any possible metastases. Targeted radionuclide therapy is a promising alternative. α particles are ideal for localized cell killing because of their high linear energy transfer and short ranges. However, upon emission of α particles, the daughter nuclides induce a recoil energy to lead decoupling from any chemical bond that may accumulate in normal tissues. Targeted α therapy can also be performed by targeted delivery systems apart from mAb, mAb fragments, peptides, and small molecules for selective tumor therapy. Targeted drug delivery systems have been developed to overcome the limitations of α therapy. Moreover, drug delivery systems are one of the most searched applications in cancer imaging and/or treatment due to their targeting ability to tumor or biocompatibility properties. The aim of this article is to summarize tumor therapy applications, targeted α RT approach, and to review the role of drug delivery systems in the delivery of α particles for cancer therapy and some instances of targeted α-emitting drug delivery systems from the literature.
Topics: Alpha Particles; Animals; Disease Models, Animal; Drug Carriers; Humans; Nanoparticles; Neoplasms; Radiation Oncology; Radiopharmaceuticals; Theranostic Nanomedicine
PubMed: 32302510
DOI: 10.1089/cbr.2019.3213