TRACER offers drug developers a platform that enables end-to-end (pre)clinical development of their astatine-211 (211At)-radiopharmaceuticals. 211At is considered highly promising for targeted radionuclide therapy. Its favorable properties include a half-life of 7.2 hours, a simple decay chain resulting in 100% alpha yield with x-ray emission suitable for SPECT imaging, and scalable production. 211At for targeted alpha therapy (TAT) has already been investigated in various preclinical studies and clinical trials.
For your research involving 211At therapeutics, TRACER supports the entire process, from production and labeling to clinical sites equipped with the necessary imaging and image-analysis capabilities.
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2026 – Astatine platform operational
Our astatine-211 platform is now operational. We have established an integrated network for supply, R&D radiolabeling, preclinical studies, GMP validation, and GMP manufacturing, as well as clinical sites with scanning capabilities to conduct your TAT clinical trial with astatine.
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211At manufacturing, labeling, and (pre)clinical studies
The development of your 211At therapy broadly consists of chemistry, manufacturing, and controls (CMC), preclinical studies, and clinical trials. Our integrated solution covers the entire process. Support in the form of individual parts is also available.
- Astatine-211 supply
- R&D radiolabeling
- Preclinical studies
- Good Manufacturing Practice (GMP) validation and manufacturing
- Clinical trial execution, including: imaging, site management, dose escalation and dosimetry
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Labeling strategy for your targeting vector
Collaboration with TRACER is possible from the very earliest phase. This means we can assist in manufacturing, but also in the development of an astatine-211 labeling strategy. 211At provides an imageable signal, but for imaging studies without therapeutic intent, a surrogate nuclide may be needed. Examples of imaging surrogates are iodine-124 or fluorine-18 for PET or iodine-123 for SPECT, but other strategies exist [1]. TRACER has extensive experience with the radiolabeling of various types of vectors, including small molecules and antibodies. Please contact us to discuss your requirements.
TRACER, one partner for radiopharmaceutical development
The main advantage of partnering with TRACER is that you have a single partner for CMC, preclinical, and clinical development. By carrying out these tasks in parallel, timelines can be shortened. For example, during the CMC process, work can already begin on designing the clinical study, qualifying clinical sites, and drafting study protocols. The CMC data and preclinical results are then brought together with the clinical study documentation to support the clinical trial application.To receive sample timelines, contact TRACER.
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Learn more about astatine-211
The following paragraphs provide information on the production, isolation, and labeling of astatine-211, its characteristics, the possibilities for imaging, and existing clinical and preclinical experience with astatine.
Astatine-211 manufacturing
[4]
Production consists of multiple steps, involving:
- Irradiation of natural of bismuth-209 (²⁰⁹Bi(α,2n) 211At) in a medium-energy cyclotron (approximately 28 MeV α-beam) [2];
- Isolation of 211At via dry distillation (commonly), liquid-liquid, or liquid-solid extraction. [3, 4].
Is Astatine production sufficient for clinical demand?
Production is not yet sufficient for large-scale clinical use, but it is sufficient to support clinical trials. However, supply is limited to several regions, although this is expected to expand in the near future. The figure below shows availability in various regions of Europe.
[2]
The map shows in green the production facilities that are in operation and in blue the facilities expected to begin production in the near future. The figure is based on a range of 450 km, although a longer range of 1,000 km is also considered possible [4].
Current astatine-211 production
Below are the cyclotrons listed with their approximate production capacity per production run. [2, 4].
Astatine-211 production in Europe
- Copenhagen University Hospital, Copenhagen, Denmark (max. 4 GBq)
- Arronax, Nantes, France (max. 1 GBq)
- Forschungszentrum Jülich, Jülich, Germany (test phase, max. 0.2 GBq)
Astatine-211 production in the USA
- Duke University Medical Center, Durham, USA (max. 9 GBq)
- University of Washington Medical Center, Seattle, USA (max. 4.3 GBq)
- University of Pennsylvania (max. 0.4 GBq)
- National Institutes of Health, Bethesda, USA (max 1.7 GBq)
- Texas A&M University, College Station, USA (max. 1.5 GBq)
- IONETIX, Lansing, USA (max. activity: not reported)
- Crocker Nuclear Lab, University of California, Davis (test phase, 1.85 MBq)
Other countries
- KIRAMS, Seoul, South Korea (test phase, 32 MBq)
- RCNP-Osaka University, Osaka, Japan (max. 3 GBq)
- QST-Takasaki, Takasaki, Japan (max. 0.3 GBq)
- QST-NIRS, Chiba, Japan (max. 1.3 GBq)
- ICPR Riken, Wako Saitama, Japan (max. 1.3 GBq)
- Fukushima Medical, Fukushima City, Japan (max. 2 GBq)
- Sichuan University, Chengdu, China (max. 0.2 GBq)
Upcoming astatine suppliers
- Alpha Nuclide Medical Technology, Ningbo, China (Announcement in 2026 that production is starting [6])
- (II) Heavy Ion Laboratory University of Warsaw (POLATOM), Warsaw, Poland (cyclotron installed in December 2023)
- (III) University of Birmingham, Birmingham, United Kingdom (announced)
- (IV) Nusano, West Valley City, Utah, USA (announced).
Astatine-211 characteristics
Astatine-211 is a halogen, but it also exhibits metallic properties and is therefore sometimes referred to as a metalloid.
The astatine-211 decay chain is short and simple. There are two routes, but both contain electron capture and alpha emission, only in a different order [5]. 41.8% decays to bismuth-207 (207Bi), delivering alpha radiation with an energy of 5.98 Mev. In the other decay branch, 58.2% decays via electron capture to polonium-211 (211Po). This provides an imageable signal that, in preclinical as well as clinical studies, has been proven to be suitable for SPECT and planar imaging. After electron capture, radioisotope 211Po is formed. 211Po has a half-life of approximately 0.5 seconds, resulting in stable lead-207 (207Pb), bringing the total of 211At to 100% alpha. The short half-life of 211Po means its decay is expected to be in close proximity of the parent nuclide. 207Bi has a much longer half-life of 31.55 years and decays mostly via electron capture.
Astatine-211 labeling radiochemistry and stability
Astatine-211 is a halogen, like fluorine and iodine. The element astatine has no stable isotopes; this presents a challenge in studying radiopharmaceuticals with astatine.
Iodine, as its closest analog, is regularly used as a surrogate for imaging studies. This also means that labeling strategies from iodine are a good starting point for astatine-211 labeling, where covalent bonding is possible rather than the use of a chelator. Labeling strategies vary based on the oxidation states of astatine, and various methods of astatination were described by Müller, M et al. [4 (6 Chemistry of Astatine-211)]. The same paper describes the lower in vivo stability of astatine-based radiopharmaceuticals compared to iodine-based ones.
“Iodine can be used as a surrogate for astatine during manufacturing and imaging studies, but suitability must be evaluated for the individual candidates”
– Maarten Brom, PhD
Astatine logistics
Logistics of the radionuclide itself and that of the radiopharmaceutical product require special attention. During storage and transport, oxidation can alter the chemical form of 211At and affect its suitability for subsequent radiolabeling. Radioactive decay reduces the available 211At activity and leads to the formation of daughter isotopes.
Imaging of astatine-211
Imaging of astatine-211 is possible from the characteristic polonium X-rays associated with the electron-capture branch of 211At decay. Below are examples with a preclinical phantom and an animal study. In the next paragraph, examples of in-human SPECT imaging are shown.
[7]
Theranostic and imaging trial approaches
Various theranostic strategies exist for imaging studies without therapeutic intent. These include the use of iodine-123 (SPECT), iodine-124 (PET), iodine-131 (therapeutic, SPECT), and astatine-209 (SPECT) [1]. There are also alternatives, like an iodine-based candidate radiolabeled with Gallium-68 (68Ga) for PET [8] or, as the clinical trial with [211At]YF2 [9] shows, a microdose study with direct imaging of 211At. In addition to the development of your astatine radiopharmaceutical, TRACER can assist you in the development of a theranostic counterpart.
Selected clinical trials with astatine-211
In-human trials with astatine-211-based radiopharmaceuticals have already been conducted. For example, to investigate an astatine-211 cancer treatment in comparison to 177Lu-based therapy [10]. When you are planning your own study, reading the papers on previously conducted astatine clinical studies can be informative.
An overview of clinical trials with astatine was published in the 2023 paper: Astatine-211 based radionuclide therapy: Current clinical trial landscape [13] and 211At targeted alpha therapy in Europe: overcoming clinical, regulatory, and infrastructure challenges [14].
Preclinical studies with Astatine-211
- 211At-labeled PSMA compounds in mouse xenograft models, 2022, [15].
- 211At stability and organ uptake compared to 131I and with and without ascorbic acid, 2026 [16].
- Targeted alpha therapy using astatine (211At)-labeled phenylalanine:
A preclinical study in glioma bearing mice, 2020 [17].
An overview of other preclinical astatine-211 studies can be found in the review paper by Müller, M et al. [4].
TRACER for astatine-211 radiopharmaceutical development
TRACER developed an end-to-end platform for manufacturing, labeling, and (pre)clinical development of your 211AT radiopharmaceutical. We support drug developers with a fully integrated solution or with individual services. You may already have a labeled candidate, or we can label or evaluate your targeting molecule or biologic with 211At, or imaging counterpart.
Abbreviations
| CMC | Chemistry Manufacturing and Controls |
| GMP | Good Manufacturing Practice |
| PET | Positron Emission Tomography |
| R&D | Research & Development |
| SPECT | Single Photon Emission Computed Tomography |
| TAT | Targeted Alpha Therapy |