Branching out – Development of radiocopper (Cu-64/Cu-67) radiopharmaceuticals for precision medicine theranostics in glioblastoma vascularization

Prosjektnummer: HNF1591-21
Ansvarlig person: Mathias Kranz
Institusjon: Universitetssykehuset Nord-Norge
Prosjektkategori: Flerårig forskningsprosjekt som omfatter flere forskere
Helsekategori: Cancer and neoplasms
Forskningsaktivitet: 4. Detection and Diagnosis, 5. Treatment Development

2024 - sluttrapport

The study investigates the potential of [67Cu]rhPSMA-10.1 for targeted radionuclide therapy (TRT) and [68Ga]rhPSMA-10.1 for PET imaging and dosimetry in glioblastoma (GBM). [67Cu]rhPSMA-10.1 and [68Ga]rhPSMA-10.1 were synthesized with high radiochemical purity (≥94%). [67Cu]rhPSMA-10.1 demonstrated a radiochemical yield (RCY) of 94% and radiochemical purity (RCP) >96%, while [68Ga]rhPSMA-10.1 achieved a radiochemical yield of 58%, with molar activity of 178 GBq/μmol. PET imaging with [68Ga]rhPSMA-10.1 showed distinct tumor uptake compared to the healthy brain, with a tumor-to-background SUVR of 1.9 ± 0.5 at 60 minutes post-injection (p.i.). Pharmacokinetic modeling revealed higher tumor perfusion (K1 = 0.3 ± 0.07 mL/cm³/min) and volume of distribution (Vt = 0.3 ± 0.05 mL/cm³) compared to the healthy brain. Tumor dosimetry estimates using PET data were consistent with SPECT validation results, supporting its reliability in pretherapeutic dosimetry. RNAscope in situ hybridization confirmed high PSMA mRNA expression in the tumor microenvironment, aligning with PET imaging results, while minimal expression was observed in healthy brain tissue. SPECT imaging with [67Cu]rhPSMA-10.1 showed increasing tumor uptake, peaking at 48 hours post-injection at 0.2 ± 0.09 %ID. Whole-body dosimetry revealed significant uptake in the liver, kidneys, and urinary bladder, indicating hepatic and renal clearance. The median tumor absorbed dose for [67Cu]rhPSMA-10.1 was estimated at 129.6 mGy based on SPECT data, consistent with predictive PET dosimetry methods. The red marrow was identified as the dose-limiting organ, allowing a maximum injection of 27 MBq, which would yield a tumor dose of 540 mGy. Dosimetry results indicated high absorbed doses in organs such as the lungs, stomach wall, and intestines. These findings align with observed biodistribution differences between [67Cu] and [68Ga]-labeled rhPSMA-10.1 due to their distinct pharmacokinetics. Comparative analysis of [68Ga]- and [67Cu]-based dosimetry highlighted strengths and limitations in using non-theranostic isotope pairs. Future studies with the 64Cu/67Cu theranostic pair are recommended to achieve greater precision in dosimetry. This study demonstrates that [67Cu]rhPSMA-10.1 and [68Ga]rhPSMA-10.1 are promising agents for theranostics in GBM. PET-based dosimetry and SPECT validation established their feasibility for TRT and dosimetry, with reliable tumor targeting and high radiochemical purity. Further investigation with optimized theranostic pairs like 64Cu/67Cu is suggested to enhance accuracy and therapeutic efficacy. The results of this study have significant implications for medical service providers, particularly in oncology and nuclear medicine. They demonstrate the feasibility of using [67Cu]rhPSMA-10.1 and [68Ga]rhPSMA-10.1 as theranostic agents, offering a dual approach for diagnosis and targeted radionuclide therapy (TRT) in glioblastoma (GBM). One of the key consequences is the potential for enhanced treatment personalization. The study underscores the value of PET-based dosimetry for pretherapeutic planning, which enables clinicians to accurately estimate tumor and organ doses. This capability allows for a transition from fixed dosing regimens to individualized treatment strategies, optimizing outcomes for GBM patients while minimizing side effects. The dual use of [67Cu]rhPSMA-10.1 for therapy and [68Ga]rhPSMA-10.1 for imaging facilitates a theranostic model of care, allowing medical facilities equipped with cyclotrons or access to radiopharmaceuticals to adopt this seamless diagnostic and therapeutic workflow. This approach aligns with precision medicine principles and enhances the quality of patient care. Additionally, the ability to synthesize [67Cu]rhPSMA-10.1 in standard biomedical cyclotrons presents a practical pathway for in-house production of therapeutic isotopes, reducing dependency on commercial suppliers, potentially lowering costs, and ensuring timely availability of radiopharmaceuticals for treatment. The study also demonstrates promising tumor uptake and dosimetry results for [67Cu]rhPSMA-10.1 in GBM, a condition with limited effective treatments. This provides medical service providers with an additional treatment modality, broadening the therapeutic arsenal for patients unresponsive to conventional therapies. Furthermore, the dosimetry data highlight the importance of monitoring and managing organ-specific toxicity, particularly in dose-limiting organs such as red marrow, kidneys, and liver. This necessitates the implementation of more rigorous follow-up protocols and supportive care measures to mitigate potential side effects. However, adopting such advanced radiopharmaceuticals requires investment in PET/SPECT imaging capabilities, cyclotrons, and trained personnel for synthesis and administration. Medical institutions would need to evaluate their readiness and invest in the necessary infrastructure to effectively implement these theranostic approaches. Finally, the study lays the foundation for future innovations, pointing toward the development of true theranostic pairs like 64Cu/67Cu for more precise dosimetry and therapeutic outcomes. Providers engaged in clinical trials or advanced research can play a pivotal role in validating and adopting these innovations, positioning themselves at the forefront of oncologic care. In conclusion, these results highlight the transformative potential of theranostics in GBM treatment, encouraging medical service providers to embrace advanced diagnostic and therapeutic technologies. By adopting these approaches, providers can offer personalized, effective, and innovative care to patients with challenging conditions like GBM.

Beskriv samarbeidet med brukerrepresentanten(e) det siste året

Det har vært dialog med leder av Hjernesvulstforeningen, Rolf Ledal, som har bekreftet interesse og velvillighet til å delta i prosjektet. Representant fra foreningen vil bli invitert til møter når prosjektsøknaden skal utvikles.

2023

Copper-67 labeled PSMA was successfully applied in animal models of brain cancer and new intern. collaborations established.Copper-67 was first time produced in Norway on a medical cyclotron and Cu-67-labeled PSMA was produced with high molar activity and purity in-house in our facilities at PET center in Tromsø. All mice tolerated the injection well and tumor uptake was confirmed by SPECT/MRI. A patent application is pending and manuscripts are under preparation.The following milestones were achieved within the last reporting period: i) Copper-67 was produced following electroplating of natural zinc and subsequent bombardment in the hospital cyclotron. Approximately 100 MBq were produced and subsequently purified for radiosynthesis. The radio production yielded in high purity copper-67 labeled PSMA. Following injection into brain tumor bearing animals, the mice were subsequently SPECT/MR imaged over the 4 consecutive days and tumor uptake confirmed. Based on these results, a patent application will be send in collaboration with an industry partner. ii) In collaboration with Mahidol University in Thailand, a PhD student visited Tromsø for a 1 year period and produced a new Glioblastoma (GBM) specific ligand. Subsequent PET/MR imaging with brain tumor bearing animals revealed high tumor uptake and encouraged us for further development of this promising compound. Furthermore, researchers from PET center Tromsø have been invited as speakers to a conference in Bangkok and delivered talks. Subsequent discussions about new common projects applications with the Thai partners is ongoing. iii) A new collaboration with BRIN in Indonesia was initiated to investigate a new GBM ligand in combination with focused ultrasound and GBM bearing animals iv) 2 manuscripts dealing with the radio tracer development of an EGFR and CDK7 specific ligand are under preparation and will be submitted for review within 2024 v) Mathias Kranz was chosen by the health faculty of UiT as their candidate for the TFS starting grant and an application was send accordingly. If receiving this 25 Min NOK grant the progression within the HN project will be secured and clinical application pursued. vi) MATHIAS KRANZ has received funding from HN starting July 2024 to continue the research started under HNF1591-21.

Beskriv samarbeidet med brukerrepresentanten(e) det siste året

Pål Oraug and Rolf Ledal (Hjernesvulstforeningen) as well as Brage Sollund and 12 representatives (Kreftforeningen) have been visiting the Tromsø PET imaging center in 2022 and where presented the current ongoing GBM research projects. Both patients´ representative organizations are included into the patient involvement in our research projects. Subsequently, during these meetings fruitful discussions were started which helped to shape our current research strategy. It was made clear to us that more hands-on are needed to conduct our ambitious goals and thus we are seeking financing for further researcher positions. Additionally, Rolf Ledal mentioned to us, that an early translation of our project into human application should be the major goal to support treatment of GBM. Hence, we decided to include PDX animal models instead of using mouse derived cell lines only. Subsequently, the patient representatives will be invited again, and current results and issues presented in order to receive feedback for this ongoing project. The user representatives made us aware that current funding organs do not focus on fast progressing disease like Glioblastoma and the research results do not reach the respective patients within their survival time. Hence, our project will try to fill this gap in translational researche as patient specific treatment results are investigated. Patients are currently recruited at UNN (REK 295739, Mathias Kranz).

2022

Year report 2022: Radiochemistry and first in vivo resultsNew metal chelators have been synthesized and labeled with Ga-68, Cu-64 and Cu-67. First in vivo results in mice show tolerability of the newly developed drug and favorable biodistribution.The following milestones were achieved in 2022: i) Cu-67 was successfully transferred from Risø Denmark to Tromsø and produced on-site at the PET imaging center in Tromsø. Further iterations are necessary to achieve increased yields, suitable for imaging studies in mice. ii) A new, Ga-68-rhPSMA-10.1 ligand was tested in animal models with Glioblastoma and showed tumor uptake and retention. A manuscript is under preparation. iii) The newly developed corroles were radiolabeled with Ga-68 and some with Cu-67. In December 2022 first in vivo experiments with Ga-68 labeled corroles were performed and PET/MR imaging confirmed favorable biodistribution of the compounds. Furthermore, no adverse effects were observed following injection of these new compounds which confirms tolerability of the newly developed structures. Further experiments will be performed in early 2023 and a PSMA linker tested in vivo. Furthermore, an abstract for an international conference in 2023 was submitted and will be published upon acceptance.

Beskriv samarbeidet med brukerrepresentanten(e) det siste året

2021

Year report 2021: Initial results from radiochemistry and preclinical model - ready for first in vivo studiesProduction of Cu-67 established at Risø/Denmark however, further purification is needed. Precursor of rhPSMA-10.1 was received and first synthesis with Ga-68 successfully performed. Following optimization of reaction properties first application in mice with brain tumor. Due to the lack of Co-64 in Tromsø no in vivo experiments possible in 2021.Glioblastoma is the most common primary tumor of the CNS and up to date there is no effective therapy available to cure high-grade glioma. All approaches, including surgery, small molecule inhibitors, antibodies, irradiation etc. could only slightly prolong the survival of the patients. One reason for this ineffective treatment is the tumor growth pattern and the high degree of heterogeneity of GBM, leading to residual tumor after surgery and chemo/radio resistance. The standard treatment of surgical resection followed by radio- and chemotherapy with temozolomide increases the medial survival to 12-14 months. Following this treatment tumor recurrence occur from residual tumor tissue. Thus, the extent of resection correlates with the progression-free and overall survival. Future treatments must be tailored to the patient specific tumor profile, a strategy known as personalized treatment. Some attempts have been made to treat the cavity using internal radionuclide therapy after GBM resection in patient. Resultantly, it was shown that the survival time was prolonged compared to other therapies of GBM. However, it was summarized that the treatment of the remaining tumor tissue in the resection cavity can be further improved by the right choice of radionuclides linked to the respective personalized targeting agent Here, the project yields the evaluation of theranostic PSMA ligands with copper isotopes for improvement of Glioblastoma treatment. Within the project, a (radio)chemist was employed from spring 2021 working fulltime at the Tromsø PET imaging center. The following milestones were achieved: (i) The production of Cu-67 was established at Risø/Denmark and transfer of the protocol to Tromsø is scheduled for 2022. In 2021 no copper isotope production was possible in Tromsø due to regulatory delays in GMP production. (ii) Analytical methods for the characterization and purification of rhPSMA10.1 labeled with Ga-68 was established. Several pH conditions were examined for the radiolabelling of rhPSMA 10.1 with 68-Ga3+. So far a suitable pH range, buffer, temperature and reagent concentrations have been identified to successfully radiolabel rhPSMA 10.1. (iii) A set of 3 new chelators was synthesized in 2021, purified and will be tested in healthy animals in 2022. These corroles strongly bind Cu2+/Cu3+ ions and may not easily trans-chelate Cu under in vivo conditions. One ligand proved difficult to purify, and thus will be substituted for a new ligand. Cold Cu2+ and Ga3+complexes of the other two ligands have been prepared and analysed spectroscopically (MS, NMR, UV-vis) confirming that these ligands bind to cold Cu2+ and Ga3+ ions. High Performance Liquid Chromatography (HPLC) a useful tool to identify the retention times of these corroles has also been performed. This was a time-consuming process as HPLC methods for corroles have not been established and reported before in literature. Thankfully, HPLC data (on retention times and stability studies) for all corrole ligands and their Cu2+ and Ga3+ complexes have now been obtained. With these data, we presently attempting to label the corrole ligand with 68-Ga3+ which hasn`t proven successful so far but there are signs that we are closing in the target complex. (iv) A mouse tumor model was established and characterized by a PET/MRI study including 40 animals. (vi) F-18-rhPSMA-7.3. was succesfully tested in vivo in brain tumor bearing animals.

Beskriv samarbeidet med brukerrepresentanten(e) det siste året

Due to the ongoing corona situation a reduced number in official meetings was performed and hence no patient group representatives were invited this year. In the following year there will be a large focus on this topic. Especially with regard of using human tumor tissue for the ongoing project. In this case, a close contact with the patients and its representatives will be focused on.

Vitenskapelige artikler

Lindemann M, Oteiza A, Martin-Armas M, Guttormsen Y, Moldes-Anaya A, Berzaghi R, Bogsrud TV, Bach-Gansmo T, Sundset R, Kranz M

Glioblastoma PET/MRI: kinetic investigation of [

Eur J Nucl Med Mol Imaging 2023 Mar;50(4):1183. Epub 2022 nov 22

PMID: 36416908

Ursula Søndergaard a b c , Kolle E. Thomas a , Kristina Søborg Pedersen c , Mathias Kranz a b , Rune Sundset a b , Angel Moldes-Anaya a b , Mikael Jensen c

Production of 67Cu at a biomedical cyclotron via 70Zn(p,α)67Cu reaction and its evaluation in a preclinical study using small animal SPECT/CT

applied-radiation-and-isotopes

Marcel Lindemann, Ana Oteiza, Montserrat Martin-Armas, Julia Bihler, Yngve Guttormsen, Angel Moldes-Anaya, Trond Bogsrud, Tore Bach-Gansmo, Rune Sundset and Mathias Kranz

A new role for PSMA in glioblastoma vascularization – PET/MRI kinetic investigation of radiohybrid F-18-rhPSMA-7.3 compared to F-18-FET and F-18-fluciclovine in an orthotopic mouse model

Journal of Nuclear Medicine June 2022, 63 (supplement 2) 2572;2022

Deltagere

Rodrigo Berzaghi Prosjektdeltaker
Mikael Jensen Prosjektdeltaker
Ursula Søndergaard Prosjektdeltaker
Trond Bogsrud Prosjektdeltaker
Hege Sagstuen Haugnes Prosjektdeltaker
Marcel Lindmann Prosjektdeltaker
Angel Moldes-Anaya Prosjektdeltaker
Montserrat Martin-Armas Prosjektdeltaker
Ana Oteiza Prosjektdeltaker
Mathias Kranz Prosjektleder
Rune Sundset Prosjektdeltaker
Ekaney Thomas Kolle Prosjektdeltaker

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