CD19 occupancy with tafasitamab increases therapeutic index of CART19 cell therapy and diminishes severity of CRS.

ABSTRACT: In the development of various strategies of anti-CD19 immunotherapy for the treatment of B-cell malignancies, it remains unclear whether CD19 monoclonal antibody therapy impairs subsequent CD19-targeted chimeric antigen receptor T-cell (CART19) therapy. We evaluated the potential interference between the CD19-targeting monoclonal antibody tafasitamab and CART19 treatment in preclinical models. Concomitant treatment with tafasitamab and CART19 showed major CD19 binding competition, which led to CART19 functional impairment. However, when CD19+ cell lines were pretreated with tafasitamab overnight and the unbound antibody was subsequently removed from the culture, CART19 function was not affected. In preclinical in vivo models, tafasitamab pretreatment demonstrated reduced incidence and severity of cytokine release syndrome and exhibited superior antitumor effects and overall survival compared with CART19 alone. This was associated with transient CD19 occupancy with tafasitamab, which in turn resulted in the inhibition of CART19 overactivation, leading to diminished CAR T apoptosis and pyroptosis of tumor cells.

Objectively Measured Physical Activity in Children With Developmental Coordination Disorder: A Systematic Review and Meta-analysis.

OBJECTIVE: To conduct a systematic review and meta-analysis to understand the difference in objectively measured physical activities (PAs) between children with and without developmental coordination disorder (DCD). DATA SOURCES: A systematic literature search of 4 databases (PubMed, Science Direct, Web of Science, and Cochrane library) was conducted in July 2023. STUDY SELECTION: Studies that met the following criteria were considered classified children with DCD based on Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV), DSM-IV-Text Revision, or DSM-V diagnosis criteria, evaluated PA using objective measurements and provided the amount of time spent in PA and/or sedentary behavior, included a control group of typically developing children, and written in English. DATA EXTRACTION: Data extracted from all included studies were: first author's surname and publication year, study design, country, total sample size, the measure of PA, the intensity of PA, categories of PA level, and main finding(s). DATA SYNTHESIS: Twelve articles met the inclusion criteria for the systematic review, 10 of which were included in the meta-analysis. The overall mean difference in moderate-to-vigorous PA (MVPA) between 2 groups was -0.17 (95% CI, -0.25 to -0.09), (I2=48.7%, P=.029). A subgroup analysis by age (ie, school-aged vs. preschool) showed a significant pooled effect size with no heterogeneity in school-aged children (ie, 6-14y) (standardized mean difference=-0.27, 95% CI, -0.38 to -0.16, I2=43.1%, P=.08). CONCLUSIONS: Children with DCD spent significantly less time participating in MVPA, particularly those aged between 6 and 14 years. These findings highlight the need for increased awareness among parents and physicians regarding insufficient participation in PA among children with DCD.

Design of a multivalent bifunctional chelator for diagnostic 64Cu PET imaging in Alzheimer's disease.

Herein, we report a 64Cu positron emission tomography (PET) imaging agent that shows appreciable in vivo brain uptake and exhibits high specific affinity for beta-amyloid (Aß) aggregates, leading to the successful PET imaging of amyloid plaques in the brains of 5xFAD mice versus those of wild-type mice. The employed approach uses a bifunctional chelator with two Aß-interacting fragments that dramatically improves the Aß-binding affinity and lipophilicity for favorable blood-brain barrier penetration, while the use of optimized-length spacers between the Cu-chelating group and the Aß-interacting fragments further improves the in vivo Aß-binding specificity and brain uptake of the corresponding 64Cu PET imaging agent.

An investigation of white matter properties as they relate to spelling behaviour in skilled and impaired readers.

RESULTS: While the inferior longitudinal fasciculus was more strongly related to spelling behaviour in skilled adults, the uncinate fasciculus was more strongly related to spelling behaviour in impaired adults. We found strong left lateralization of the arcuate fasciculus and inferior longitudinal fasciculus in both groups. However, lateralization of the inferior frontal occipital fasciculus was more strongly related to spelling response time behaviour in skilled adults, whereas lateralization of the uncinate fasciculus was more strongly related to spelling accuracy behaviour in the impaired adults. CONCLUSION: This study provides some useful information for understanding the underlying white matter pathways that support spelling in skilled and impaired adults and underscore the advantage of adopting multiple spelling tasks and outcomes (i.e., response time and accuracy) to better characterize brain-behaviour relationships in skilled and impaired adults.

Neutral Ligands as Potential 64Cu Chelators for Positron Emission Tomography Imaging Applications in Alzheimer's Disease.

Positron emission tomography (PET), which uses positron-emitting radionuclides to visualize and measure processes in the human body, is a useful noninvasive diagnostic tool for Alzheimer's disease (AD). The development of longer-lived radiolabeled compounds is essential for further expansion of the use of PET imaging in healthcare, and diagnostic agents employing longer-lived radionuclides such as 64Cu (t1/2 = 12.7 h, ß+ = 17%, ß- = 39%, electron capture EC = 43%, and Emax = 0.656 MeV) can accomplish this task. One limitation of 64Cu PET agents for neuroimaging applications is their limited lipophilicity due to the presence of several anionic groups needed to ensure strong Cu chelation. Herein, we evaluate a series of neutral chelators containing the 1,4,7-triazacyclononane or 2,11-diaza[3.3](2,6)pyridinophane macrocycles that have pyridyl-containing arms incorporating Aß-peptide-interacting fragments. The crystal structures of the corresponding Cu complexes confirm that the pyridyl N atoms are involved in binding to Cu. Radiolabeling and autoradiography studies show that the compounds efficiently chelate 64Cu, and the resulting complexes exhibit specific binding to the amyloid plaques in the AD mouse brain sections versus wild-type controls.

Divalent 2-(4-Hydroxyphenyl)benzothiazole Bifunctional Chelators for 64Cu Positron Emission Tomography Imaging in Alzheimer's Disease.

Herein, we report a new series of divalent 2-(4-hydroxyphenyl)benzothiazole bifunctional chelators (BFCs) with high affinity for amyloid ß aggregates and favorable lipophilicity for blood-brain barrier penetration. The addition of an alkyl carboxylate ester pendant arm offers high binding affinity toward Cu(II). The novel BFCs form stable 64Cu-radiolabeled complexes and exhibit promising partition coefficient (logD) values of 1.05-1.85. Among the five compounds tested, the 64Cu-YW-15 complex exhibits significant staining of amyloid ß plaques in ex vivo autoradiography studies. In addition, biodistribution studies show that 64Cu-YW-15-Me exhibits moderate brain uptake (0.69 ± 0.08 %ID/g) in wild type mice.

Amphiphilic Distyrylbenzene Derivatives as Potential Therapeutic and Imaging Agents for Soluble and Insoluble Amyloid ß Aggregates in Alzheimer's Disease.

Alzheimer's Disease (AD) is the most common neurodegenerative disease, and efficient therapeutic and early diagnostic agents for AD are still lacking. Herein, we report the development of a novel amphiphilic compound, LS-4, generated by linking a hydrophobic amyloid-binding distyrylbenzene fragment with a hydrophilic triazamacrocycle, which dramatically increases the binding affinity toward various amyloid ß (Aß) peptide aggregates, especially for soluble Aß oligomers. Moreover, upon the administration of LS-4 to 5xFAD mice, fluorescence imaging of LS-4-treated brain sections reveals that LS-4 can penetrate the blood-brain barrier and bind to the Aß oligomers in vivo. In addition, the treatment of 5xFAD mice with LS-4 reduces the amount of both amyloid plaques and associated phosphorylated tau aggregates vs the vehicle-treated 5xFAD mice, while microglia activation is also reduced. Molecular dynamics simulations corroborate the observation that introducing a hydrophilic moiety into the molecular structure of LS-4 can enhance the electrostatic interactions with the polar residues of the Aß species. Finally, exploiting the Cu2+-chelating property of the triazamacrocycle, we performed a series of imaging and biodistribution studies that show the 64Cu-LS-4 complex binds to the amyloid plaques and can accumulate to a significantly larger extent in the 5xFAD mouse brains vs the wild-type controls. Overall, these results illustrate that the novel strategy, to employ an amphiphilic molecule containing a hydrophilic moiety attached to a hydrophobic amyloid-binding fragment, can increase the binding affinity for both soluble and insoluble Aß aggregates and can thus be used to detect and regulate various Aß species in AD.

Amyloid ß-Binding Bifunctional Chelators with Favorable Lipophilicity for 64Cu Positron Emission Tomography Imaging in Alzheimer's Disease.

Herein, we report a new series of bifunctional chelators (BFCs) with a high affinity for amyloid aggregates, a strong binding affinity toward Cu(II), and favorable lipophilicity for potential blood-brain barrier penetration. The alkyl carboxylate ester pendant arms offer up to 3 orders of magnitude higher binding affinity toward Cu(II) and enable the BFCs to form stable 64Cu-radiolabeled complexes. Among the five compounds tested, the 64Cu-YW-7 and 64Cu-YW-10 complexes exhibit strong and specific staining of amyloid plaques in ex vivo autoradiography studies. Importantly, these BFCs have promising partition coefficient (log Doct) values of 0.91-1.26 and show some brain uptake in biodistribution studies using CD-1 mice. Overall, these BFCs could serve as lead compounds for the development of positron emission tomography imaging agents for AD diagnosis.

The first two case reports of confirmed Mpox in patients with syphilis in a dense urban setting, Can Tho, Vietnam: From clinical presentation, treatment, and epidemiological surveillance to prevention.

This report elucidated the first two noteworthy cases of Mpox that manifested as an emerging concern in a densely populated city in Vietnam. Two male patients (22 and 27 years old) were admitted to the hospital due to the presence of small pustules on their faces, accompanied by symptoms of fatigue, drowsiness, and muscle pain. Reverse transcription-polymerase chain reaction confirmed the presence of Mpox. The patients possessed a medical history involving four previous treatments for syphilis, a continuous antiretroviral regimen for over 3 years, no previous history of chickenpox, a lack of vaccination against chickenpox, and engagement in intimate contact with other men. Following a 14-day isolation period coupled with appropriate medical interventions, both patients exhibited stable health conditions, marked by the absence of fever and the desiccation of skin blisters. Subsequently, they were discharged with instructions for ongoing health monitoring. Comprehensive surveillance and monitoring approaches have been implemented for all individuals in close contact with the affected patients, adhering to established guidelines. Notably, no suspected cases have been identified during the current surveillance efforts. The collective findings underscore the significance of robust surveillance, continuous monitoring, and strategic vaccination initiatives, particularly in densely populated urban centers, to effectively manage and mitigate the impact of Mpox outbreaks.

PSMA-reactive NB7 single domain antibody fragment: A potential scaffold for developing prostate cancer theranostics.

INTRODUCTION: Single domain antibody fragments (sdAbs) are an appealing scaffold for radiopharmaceutical development due to their small size (~15 kDa), high solubility, high stability, and excellent tumor penetration. Previously, we developed NB7 sdAb, which has very high affinity for an epitope on PSMA that is different from those targeted by small molecule PSMA inhibitors. Herein, we evaluated NB7 after radioiodination using [*I]SGMIB (1,3,4-isomer) and iso-[*I]SGMIB (1,3,5-isomer), as well as their 211At-labeled analogues. METHODS: [*I]SGMIB, iso-[*I]SGMIB, [211At]SAGMB, and iso-[211At]SAGMB conjugates of NB7 sdAb were synthesized and their binding affinity, cell uptake and internalization were assessed in PSMA+ PC3 PIP and PSMA- PC3 flu cells. Biodistribution studies were performed in mice bearing PSMA+ PC3 PIP xenografts. First, a single-label experiment evaluated the tissue distribution of a NB7 bearing a His6-tag (NB7H6) and labeled with iso-[125I]SGMIB. Three paired-label experiments then were performed to compare: a) NB7 labeled using [*I]SGMIB and iso-[*I]SGMIB, b) 131I- vs 211At-labeled NB7 conjugates and c) [125I]SGMIB-NB7H6 to the small molecule PSMA inhibitor [131I]YF2. RESULTS: All NB7 radioconjugates bound specifically to PSMA with dissociation constants, Kd, in the low nM range (1.4-6.4 nM). An initial biodistribution study demonstrated good tumor uptake for iso-[125I]SGMIB-NB7H6 (7.2 ± 1.5 % ID/g at 1 h) and no deleterious effect of the His6-tag on renal activity levels, which declined to 3.1 ± 1.1 % ID/g by 4 h. Paired-label biodistribution found no distinction between the two SGMIB isomer NB7 conjugates with the [131I]SGMIB-NB7-to-iso-[125I]SGMIB-NB7 tumor uptake ratios not significantly different from unity: 1.06 ± 0.08 at 1 h, 1.04 ± 0.12 at 4 h, and 1.07 ± 0.09 at 24 h. Both isomer conjugates cleared rapidly from normal tissues and exhibited very low uptake in thyroid, lacrimal and salivary glands. Paired-label biodistribution of [131I]SGMIB-NB7H6 and [211At]SAGMB-NB7H6 demonstrated similar tumor uptake and kidney clearance for the two radioconjugates. However, levels of 211At in thyroid, stomach, salivary and lacrimal glands were significantly higher (P < 0.05) that those for 131I suggesting greater dehalogenation for [211At]SAGMB-NB7H6. Finally, co-administration of [125I]SGMIB-NB7H6 and [131I]YF2 demonstrated good tumor uptake for both with considerably more rapid renal clearance for the NB7 radioconjugate. CONCLUSION: NB7 radioconjugates exhibited good accumulation in PSMA-positive xenografts with rapid clearance from kidney and other normal tissues. We conclude that NB7 is a potentially useful scaffold for developing PSMA-targeted theranostics with different characteristics than current small molecule and antibody-based approaches.

A high throughput cell stretch device for investigating mechanobiology in vitro.

Mechanobiology is a rapidly advancing field, with growing evidence that mechanical signaling plays key roles in health and disease. To accelerate mechanobiology-based drug discovery, novel in vitro systems are needed that enable mechanical perturbation of cells in a format amenable to high throughput screening. Here, both a mechanical stretch device and 192-well silicone flexible linear stretch plate were designed and fabricated to meet high throughput technology needs for cell stretch-based applications. To demonstrate the utility of the stretch plate in automation and screening, cell dispensing, liquid handling, high content imaging, and high throughput sequencing platforms were employed. Using this system, an assay was developed as a biological validation and proof-of-concept readout for screening. A mechano-transcriptional stretch response was characterized using focused gene expression profiling measured by RNA-mediated oligonucleotide Annealing, Selection, and Ligation with Next-Gen sequencing. Using articular chondrocytes, a gene expression signature containing stretch responsive genes relevant to cartilage homeostasis and disease was identified. The possibility for integration of other stretch sensitive cell types (e.g., cardiovascular, airway, bladder, gut, and musculoskeletal), in combination with alternative phenotypic readouts (e.g., protein expression, proliferation, or spatial alignment), broadens the scope of high throughput stretch and allows for wider adoption by the research community. This high throughput mechanical stress device fills an unmet need in phenotypic screening technology to support drug discovery in mechanobiology-based disease areas.

Mesenchymal stromal cells with chimaeric antigen receptors for enhanced immunosuppression.

Allogeneic mesenchymal stromal cells (MSCs) are a safe treatment option for many disorders of the immune system. However, clinical trials using MSCs have shown inconsistent therapeutic efficacy, mostly owing to MSCs providing insufficient immunosuppression in target tissues. Here we show that antigen-specific immunosuppression can be enhanced by genetically modifying MSCs with chimaeric antigen receptors (CARs), as we show for E-cadherin-targeted CAR-MSCs for the treatment of graft-versus-host disease in mice. CAR-MSCs led to superior T-cell suppression and localization to E-cadherin+ colonic cells, ameliorating the animals' symptoms and survival rates. On antigen-specific stimulation, CAR-MSCs upregulated the expression of immunosuppressive genes and receptors for T-cell inhibition as well as the production of immunosuppressive cytokines while maintaining their stem cell phenotype and safety profile in the animal models. CAR-MSCs may represent a widely applicable therapeutic technology for enhancing immunosuppression.

Correction: Trinh et al. LMP1-EBV Gene Deletion Mutations and HLA Genotypes of Nasopharyngeal Cancer Patients in Vietnam. Pathophysiology 2023, 30, 1-12.

The authors would like to make the following corrections to the paper published [...].

Moderation of parental socioeconomic status on the relationship between birth health and developmental coordination disorder at early years.

Objective: This study investigated whether parental SES moderates the effect of birth health on Developmental Coordination Disorder (DCD) in preschool children. Methods: One hundred and twenty-two children aged 4 to 6 years were enrolled in the study. The Movement Assessment Battery for Children --2nd Edition (MABC-2) test was used to assess the motor coordination of children. They were preliminarily categorized into either the DCD (<=16th percentile, n = 23) or typically developing (TD) group (>16th percentile, n = 99) based on the testing results. All children in the DCD group were further confirmed to meet other diagnostic criteria of the DSM-V using the intellectual test and parental questionnaires. Moderation analysis was conducted using the PROCESS macro for SPSS, and 95% confidence intervals with a bootstrap procedure were calculated to identify the significant moderating effect. Results: Maternal education (unstandardized coefficient = 0.6805, SE = 0.3371, p < 0.05) and maternal employment status (unstandardized coefficient = 0.6100, SE = 0.3059, p < 0.05) were found to moderate the relationship between birth length and the probability of having DCD. Moreover, the relationship between birth weight and the probability of having DCD was moderated by the annual household income (unstandardized coefficient = -0.0043, SE = 0.0022, p < 0.05). Conclusion: The lower maternal education level and maternal unemployment strengthened the negative relationship between birth length and the probability of having DCD. Additionally, the negative relationship between birth weight and the probability of having DCD was statistically significant in high annual household salaries.

Which threshold do we trust? A comparison of threshold measurements in adult bone-conduction device users and normal hearing adults.

OBJECTIVES: Advancements in prescriptive formulae for bone-conduction hearing devices (BCDs) have highlighted the importance of measuring in-situ bone-conduction hearing thresholds. In-situ measurements are performed within the BCD manufacturer's software, using the patient's BCD as a transducer. While in-situ testing is a different approach than standard diagnostic bone-conduction testing, both approaches are in fact measuring the same inner ear hearing. Despite this, each approach may result in different thresholds for the same individual. This study aimed to answer the following question: In adults with normal hearing and adults who currently wear a bone-conduction device, are there differences and, if so, how large are these differences when thresholds are measured using different approaches? DESIGN: Bone-conduction hearing thresholds were measured for a group 32 normal hearing participants and a group 15 percutaneous BCD users. The normal hearing participants were tested in two conditions: (1) in-situ, with a BCD worn on a soft-band and (2) with the B71 bone-conduction diagnostic transducer. The BCD users were tested in these two conditions and (3) in-situ with a BCD attached to their abutment. In-situ hearing thresholds were measured with BCDs from two manufacturers. The mean intra-subject differences between these conditions were calculated. RESULTS: For the normal hearing participants, BCD softband thresholds were poorer than the thresholds obtained with the diagnostic transducer across all tested frequencies. The average differences between the BCD softband thresholds and the diagnostic transducer were particularly large in the high frequencies (13 to 35 dB from 3 to 6 kHz). Similar differences were observed for the BCD user participants when comparing their BCD softband thresholds to the diagnostic transducer thresholds. The in-situ percutaneous thresholds were on average better than the diagnostic bone-conduction thresholds, although the differences were not statistically significant. Skin attenuation, calibration differences, and BCD characteristics were contributing factors to these differences. CONCLUSIONS: The intra-subject differences measured in this study confirmed that using different bone-conduction transducers results in the measurement (i.e., recording) of different hearing threshold levels. These results support the necessity for a measurement tool able to measure audibility at threshold independent of the various coupling configurations used in bone-conduction amplification. An effective measurement tool would be required to take into account, or bypass, the factors contributing to the differences measured in this study. Until such a tool is commercially available, clinicians will continue to face uncertainty when fitting and attempting to assess the audibility of passive transcutaneous BCDs.

A comparison of 64Cu-labeled bi-terminally PEGylated A20FMDV2 peptides targeting integrin ανß6.

Expression of epithelial-specific integrin ανß6 is up-regulated in various aggressive cancers and serves as a prognostic marker. Integrin-targeted PET imaging probes have been successfully developed and tested in the clinic. Radiotracers based on the peptide A20FMDV2 derived from foot-and-mouth disease virus represent specific and selective PET ligands for imaging ανß6-positive cancers. The present study aims to describe the radiolabeling, in vitro and in vivo evaluation of a bi-terminally PEGylated A20FMDV2 conjugated with DOTA or PCTA for 64Cu radiolabeling. Stability studies showed radiolabeled complexes remained stable up to 24 h in PBS and human serum. In vitro cell assays in CaSki cervical cancer cells and BxPC-3 pancreatic cancer cells confirmed that the peptides displayed high affinity for αvß6 with Kd values of ~50 nM. Biodistribution studies revealed that [64Cu] Cu-PCTA-(PEG28)2-A20FMDV2 exhibited higher tumor uptake (1.63 ± 0.53 %ID/g in CaSki and 3.86 ± 0.58 %ID/g in BxPC-3 at 1 h) when compared to [64Cu]Cu-DOTA-(PEG28)2-A20FMDV2 (0.95 ± 0.29 %ID/g in CaSki and 2.12 ± 0.83 %ID/g in BxPC-3 at 1 h) . However, higher tumor uptake was accompanied by increased radioactive uptake in normal organs. Therefore, both peptides are appropriate for imaging ανß6-positive lesions although further optimization is needed to improve tumor-to-normal-tissue ratios.

Therapeutic Efficacy of 177Lu-Labeled A20FMDV2 Peptides Targeting ανß6.

Integrin ανß6 promotes migration and invasion of cancer cells, and its overexpression often correlates with poor survival. Therefore, targeting ανß6 with radioactive peptides would be beneficial for cancer imaging and therapy. Previous studies have successfully developed radiotracers based on the peptide A20FMDV2 that showed good binding specificity for ανß6. However, one concern of these ανß6 integrin-targeting probes is that their rapid blood clearance and low tumor uptake would preclude them from being used for therapeutic purposes. In this study, albumin binders were used to increase tumor uptake for therapeutic applications while the non-albumin peptide was evaluated as a potential positron emission tomography (PET) imaging agent. All peptides used the DOTA chelator for radiolabeling with either 68Ga for imaging or 177Lu for therapy. PET imaging with [68Ga]Ga-DOTA-(PEG28)2-A20FMDV2 revealed specific tumor uptake in ανß6-positive tumors. Albumin-binding peptides EB-DOTA-(PEG28)2-A20FMDV2 and IBA-DOTA-(PEG28)2-A20FMDV2 were radiolabeled with 177Lu. Biodistribution studies in normal mice showed longer blood circulation times for the albumin binding peptides compared to the non-albumin peptide. Therapy studies in mice demonstrated that both 177Lu-labeled albumin binding peptides resulted in significant tumor growth inhibition. We believe these are the first studies to demonstrate the therapeutic efficacy of a radiolabeled peptide targeting an ανß6-positive tumor.

68Ga-Labeled Benzothiazole Derivatives for Imaging Aß Plaques in Cerebral Amyloid Angiopathy.

Timely diagnostic imaging plays a crucial role in managing cerebral amyloid angiopathy (CAA)-the condition in which amyloid ß is deposited on blood vessels. To selectively map these amyloid plaques, we have designed amyloid-targeting ligands that can effectively complex with 68Ga3+ while maintaining good affinity for amyloid ß. In this study, we introduced novel 1,4,7-triazacyclononane-based bifunctional chelators (BFCs) that incorporate a benzothiazole moiety as the Aß-binding fragment and form charged and neutral species with 68Ga3+. In vitro autoradiography using 5xFAD and WT mouse brain sections (11-month-old) suggested strong and specific binding of the 68Ga complexes to amyloid ß. Biodistribution studies in CD-1 mice revealed a low brain uptake of 0.10-0.33% ID/g, thus suggesting 68Ga-labeled novel BFCs as promising candidates for detecting CAA.

2-(4-Hydroxyphenyl)benzothiazole dicarboxylate ester TACN chelators for 64Cu PET imaging in Alzheimer's disease.

Herein we report a new series of bifunctional chelators (BFCs) with high affinity for amyloid ß aggregates, strong binding affinity towards Cu(II), and favorable lipophilicity for potential blood-brain barrier (BBB) penetration. The alkyl carboxylate ester pendant arms show high binding affinity towards Cu(II). The BFCs form stable 64Cu-radiolabeled complexes and exhibit favorable partition coefficient (log D) values of 0.75-0.95. Among the five compounds tested, 64Cu-YW-1 and 64Cu-YW-13 complexes exhibit significant staining of amyloid plaques in ex vivo autoradiography studies.

Copper-67-Labeled Bombesin Peptide for Targeted Radionuclide Therapy of Prostate Cancer.

The gastrin-releasing peptide receptor (GRPR) is a promising molecular target for imaging and therapy of prostate cancer using bombesin peptides that bind to the receptor with high affinity. Targeted copper theranostics (TCTs) using copper radionuclides, 64Cu for imaging and 67Cu for therapy, offer significant advantages in the development of next-generation theranostics. [64Cu]Cu-SAR-BBN is in clinical development for PET imaging of GRPR-expressing cancers. This study explores the therapeutic efficacy of [67Cu]Cu-SAR-BBN in a pre-clinical mouse model. The peptide was radiolabeled with 67Cu, and specific binding of the radiolabeled peptide towards GRPR-positive PC-3 prostate cancer cells was confirmed with 52.2 ± 1.4% total bound compared to 5.8 ± 0.1% with blocking. A therapy study with [67Cu]Cu-SAR-BBN was conducted in mice bearing PC-3 tumors by injecting 24 MBq doses a total of six times. Tumor growth was inhibited by 93.3% compared to the control group on day 19, and median survival increased from 34.5 days for the control group to greater than 54 days for the treatment group. The ease and stability of the radiochemistry, favorable biodistribution, and the positive tumor inhibition demonstrate the suitability of this copper-based theranostic agent for clinical assessment in the treatment of cancers expressing GRPR.