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Several exploratory studies have demonstrated the feasibility of cholecystokinin-2 receptor (CCK2R) targeting in patients with medullary thyroid carcinoma (MTC) and other neuroendocrine tumors (NETs). We report the results of a prospective phase I/IIA pilot study (clinicaltrials.gov NCT06155994) conducted at our center with the 68 Ga-labeled peptide analog DOTA-DGlu-Ala-Tyr-Gly-Trp-(N-Me)Nle-Asp-1-Nal-Phe-NH 2 ( 68 Ga-DOTA-MGS5). Methods: Six patients with advanced MTC and 6 patients with gastroenteropancreatic and bronchopulmonary NETs confirmed by previous PET/CT imaging with other PET tracers received a single dose of 180 MBq of 68 Ga-DOTA-MGS5. The first 6 patients enrolled in the study were included in the dosimetry evaluation, and safety was assessed in all 12 patients. PET/CT imaging was performed at different time points after injection to perform dosimetric calculations and to determine the optimal imaging time window. In addition, blood and urine samples were collected for pharmacokinetic assessments. Results: The administration of 68 Ga-DOTA-MGS5 was well tolerated, with minor adverse drug reactions occurring only in 3 patients. 68 Ga-DOTA-MGS5 was cleared rapidly from the blood, with less than 21% of the injected activity present in blood 215 ± 10 min after injection. Tracer elimination occurred mainly through the kidneys, with a cumulative urinary excretion greater than 40% 3 h after injection. A high percentage of intact radiopeptide was confirmed in plasma. The highest absorbed dose was found for the urinary bladder wall, the stomach wall, and the kidneys, with an effective dose of 0.023 ± 0.007 mSv/MBq. The time points of 1 and 2 h after injection proved to be optimal for PET/CT imaging. In the 6 patients included in the dosimetry evaluation, local metastasis was confirmed in 2 patients with advanced MTC, whereas only 1 of 4 patients with gastroenteropancreatic NETs was positive in 68 Ga-DOTA-MGS5 PET/CT. Conclusion: Besides confirming the safety of administration, within the phase I part of the prospective clinical trial, an acceptable effective whole-body dose, an overall favorable biodistribution, and the feasibility of cholecystokinin-2 receptor imaging could be shown for 68 Ga-DOTA-MGS5., (© 2025 by the Society of Nuclear Medicine and Molecular Imaging.)

Purpose: Radiolabelled minigastrin (MG) analogues targeting the cholecystokinin-2 receptor (CCK2R) have proven to be a promising approach for peptide receptor radionuclide therapy (PRRT). In this study, we report on the radiopharmaceutical development and standardization of the preparation of [ 177 Lu]Lu-DOTA-MGS5 using an automated synthesis module. Furthermore, we present the preclinical tests required to move forward towards a first therapeutic clinical trial as well as preliminary clinical dosimetry data., Methods: Five individual batches of [ 177 Lu]Lu-DOTA-MGS5 were synthesized and analysed according to predefined quality control specifications. Cell-based experiments and biodistribution studies were performed to evaluate the specific receptor binding and tumour uptake of the radiopharmaceutical formulation. A preclinical dosimetry study was carried out in tumour xenografted mice and a first dosimetry study was performed in a patient with small cell lung cancer., Results: The automated cassette-based production of [ 177 Lu]Lu-DOTA-MGS5 resulted in a product with high radiochemical purity of > 98% and high stability. The new radiopharmaceutical showed a favourable biodistribution profile in A431-CCK2R xenografted BALB/c nude mice. Pharmacokinetic data obtained in mice and dosimetry extrapolation demonstrated the feasibility of PRRT. In the preliminary patient-specific dosimetry study, a low risk of toxicity was shown and a mean absorbed dose of 12.5 ± 10.2 (1.2-28) Gy/GBq was calculated for delineable tumour lesions., Conclusion: The radiopharmaceutical development and the preclinical/clinical results support the initiation of a first clinical trial to evaluate the therapeutic potential of [ 177 Lu]Lu-DOTA-MGS5 in PRRT., Competing Interests: Declarations. Ethics approval: All animal experiments were approved by the Austrian Ministry of Science (2022–0.351.553) or by the Dutch animal ethics committee (CCD) of the Radboud University and the Nijmegen Medical Centre animal ethics committee (RUDEC) (2020–0007–020). The first dosimetry study in a patient with SCLC was conducted on a named-patient basis. Consent to participate: Written informed consent was obtained from the patient in accordance with the Declaration of Helsinki. Consent to publish: The patient has provided consent for the publication of the data included in this article. Competing interests: EG and AH are listed as an inventor on the European patent application no. 17174973. EG consults Evergreen Theragnostics, Inc. in product development. No other conflict of interest relevant to this article was reported. Clinical trial: Not applicable., (© 2024. The Author(s).)

Different attempts have been made in the past two decades to develop radiolabeled peptide conjugates with enhanced pharmacokinetic properties in order to improve the application for tumor imaging and peptide receptor radionuclide therapy (PRRT), which targets the cholecystokinin-2 receptor (CCK2R). In this paper, the influence of different side chain and peptide bond modifications has been explored for the minigastrin analog DOTA-DGlu-Ala-Tyr-Gly-Trp-( N -Me)Nle-Asp-1Nal-NH 2 (DOTA-MGS5). Based on this lead structure, five new derivatives were synthesized for radiolabeling with trivalent radiometals. Different chemical and biological properties of the new derivatives were analyzed. Receptor interaction of the peptide derivatives and cell internalization of the radiolabeled peptides were studied in A431-CCK2R cells. The stability of the radiolabeled peptides in vivo was investigated using BALB/c mice. Tumor targeting of all 111 In-labeled peptide conjugates, and of a selected compound radiolabeled with gallium-68 and lutetium-177, was evaluated in BALB/c nude mice xenografted with A431-CCK2R and A431-mock cells. All 111 In-labeled conjugates, except [ 111 In]In-DOTA-[Phe 8 ]MGS5, showed a high resistance against enzymatic degradation. A high receptor affinity with IC 50 values in the low nanomolar range was confirmed for most of the peptide derivatives. The specific cell internalization over time was 35.3-47.3% for all radiopeptides 4 h after incubation. Only [ 111 In]In-DOTA-MGS5[NHCH 3 ] exhibited a lower cell internalization of 6.6 ± 2.8%. An overall improved resistance against enzymatic degradation was confirmed in vivo. Of the radiopeptides studied, [ 111 In]In-DOTA-[( N -Me)1Nal 8 ]MGS5 showed the most promising targeting properties, with significantly increased accumulation of radioactivity in A431-CCK2R xenografts (48.1 ± 9.2% IA/g) and reduced accumulation of radioactivity in stomach (4.2 ± 0.5% IA/g). However, in comparison with DOTA-MGS5, a higher influence on the targeting properties was observed for the change of radiometal, resulting in a tumor uptake of 15.67 ± 2.21% IA/g for [ 68 Ga]Ga-DOTA-[( N -Me)1Nal 8 ]MGS5 and 35.13 ± 6.32% IA/g for [ 177 Lu]Lu-DOTA-[( N -Me)1Nal 8 ]MGS5.

On-site and real-time clinical monitoring have been progressed dramatically by integrating biosensor science with portable digital electronic technology. Clustered regularly interspaced short palindromic repeats (CRISPR) with association of RNA-guided nucleases (CrRNA-Cas enzymes) have achieved novel CRISPR/Cas biosensing science as a promising revolutionized diagnostic technology for portable and on-site healthcare monitoring and diagnostics. Among several available CRISPR/Cas systems, CRISPR/Cas12a and CRISPR/Cas13a conjugates are utilized broadly in biosensor design, because of their capability to cleave both target and non-target sequences. With the advantages of portability, cost-effectiveness, facile operation, high durability, and reproducibility, CRISPR/Cas-based biosensing techniques are a perfect choice for designing ultra-sensitive point-of-care diagnostic devices with amplified response signals. In the present review, we summarize the advances in the CRISPR/Cas-based biosensors with the focus on healthcare and diagnostic purposes. The cooperation of nanomaterial engineering with CRISPR/Cas biosensors is also represented to attain a promising viewpoint for offering novel user-friendly test kits for announcing ultra-low levels of diverse targets in the future., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Colorimetric approaches have received noticeable attention among sensing methods in view of simplicity and watching the color change of sample by the naked eyes. However, developing colorimetric sensing methods which show high sensitivity is still problematic. Herein, based on CRISPR-Cas12a, rolling circle amplification (RCA) and catalytic activity of gold nanoparticles (AuNPs), a colorimetric aptasensor was introduced for highly sensitive detection of aflatoxin M 1 (AFM 1 ). In the presence of AFM 1 , the CRISPR-Cas12a is inactivated and large single-stranded DNA (ssDNA) structures are formed on the surface of AuNPs following the addition of T4 DNA ligase and phi29 DNA polymerase. So, the sample color remains yellow after addition of 4-nitrophenol. However, no huge DNA structure is observed on the surface of AuNPs in the absence of target because of activation of CRISPR-Cas12a and digestion of primer. So, the color of sample switches to colorless. The results indicated that the biosensor had high selectivity toward AFM 1 and the approach achieved a detection limit as low as 0.05 ng/L. In addition, it could sensitively identify AFM 1 in the spiked milk samples. Overall, this approach is highly sensitive and does not require sophisticated equipment. Therefore, it maintains promising potential for other mycotoxins detection in real samples by simply replacing the applied sequences., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)