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Aim: The objective of this study was to compare the detection rates of [ 18 F]PSMA-1007 and [ 18 F]Fluciclovine in early biochemical recurrence (BCR) of prostate cancer, i.e. with low prostate-specific antigen (PSA) levels (0.2-5.0 µg/L)., Methods: This was a prospective, single-center (Radboudumc; Nijmegen, The Netherlands), comparative phase II diagnostic imaging study (NCT04239742). The main inclusion criteria were histologically proven adenocarcinoma of the prostate, BCR after radical treatment with two consecutive (rising) PSA values (0.2-5.0 µg/L). Patients underwent both [ 18 F]PSMA-1007 PET/CT and [ 18 F]Fluciclovine PET/CT within two weeks. Both scans were blindly scored by three independent nuclear medicine physicians. Hereafter, a result per scan and region was generated by consensus. The primary outcome was to compare the detection rate on a patient and region level. Secondary objectives were to determine detection rate stratified for PSA value, inter-reader agreement, and SUV measurements. For lesion confirmation a composite reference score was established using follow-up data., Results: Data of fifty patients were included, median age of 71 (IQR: 67-74) years and median PSA value of 0.38 (IQR: 0.30-1.55) µg/L. Detection rates were 68% (34/50) for [ 18 F]PSMA-1007 and 42% (21/50) for [ 18 F]Fluciclovine on a patient level (p < 0.001). Detection rates stratified for PSA value of [ 18 F]PSMA-1007 in comparison with [ 18 F]Fluciclovine were for PSA 0.2-0.5 µg/L; 60.7% versus 25.0% (p = 0.002); and for PSA ≥ 0.5 µg/L; 77.3% versus 63.6% (p = 0.250). There was a trend for higher inter-reader agreement with [ 18 F]PSMA-1007. SUV max (p < 0.001) was significantly higher for [ 18 F]PSMA-1007 in comparison to [ 18 F]Fluciclovine., Conclusion: In patients with early BCR of prostate cancer after radical surgery or radiotherapy, [ 18 F]PSMA-1007 demonstrated a significantly higher detection rate than [ 18 F]Fluciclovine. This is particularly relevant since earlier and more accurate detection of a BCR can guide salvage therapy into a tailored strategy which may improve outcomes., Trial Registration: ClinicalTrials.gov, NCT04239742. Registered 02 January 2020, https://clinicaltrials.gov/study/NCT04239742 ., Competing Interests: Declarations. Ethical approval and consent to participate: This study was performed in line with the principles of the Declaration of Helsinki (version 2013) and approved by the medical ethical committee Arnhem-Nijmegen. All patients provided written informed consent. Consent for publication: Not applicable Competing interests: BP received research support from Novartis, ABX advanced biochemical compounds GmbH, JN received research support from Novartis, ABX advanced biochemical compounds GmbH, MJ received research support from Novartis, ABX advanced biochemical compounds GmbH. RH received consultancy fees from ABX advance biochemical compounds GmbH and Blue Earth Diagnostics. No other potential conflicts of interest relevant to this article exist., (© 2024. The Author(s).)

There is an urgent need for novel systemic therapies for recurrent/systemic salivary gland cancer, as current treatment options are scarce. [ 68 Ga]Ga-PSMA-11 PET/CT revealed relevant uptake of prostate-specific membrane antigen (PSMA) in adenoid cystic carcinoma (AdCC) and salivary duct carcinoma (SDC). Therefore, we assessed the safety, feasibility, efficacy and radiation dosimetry of [ 177 Lu]Lu-PSMA-I&T treatment in AdCC and SDC patients in a prospective pilot study. Methods: This single-center, single-arm study intended to include 10 recurrent/metastatic AdCC patients and five recurrent/metastatic SDC patients. AdCC patients could only participate in case of progressive and/or symptomatic disease. Patients required ≥ 1 lesion ≥ 1.5 cm with an SUV max on [ 68 Ga]Ga-PSMA-11 PET/CT above liver SUV mean . Patients were planned to receive four cycles ~ 7.4 GBq [ 177 Lu]Lu-PSMA-I&T. In case of progressive disease per RECIST 1.1 at mid-treatment evaluation after two cycles, treatment was discontinued. Safety was the primary endpoint. Secondary endpoints included objective response rate (ORR), tumor- and organ-absorbed radiation doses and progression-free survival. Results: After screening, 10 out of 15 (67%) AdCC and two out of 10 (20%) SDC patients were eligible. Two patients (17%) demonstrated grade 3 treatment-related toxicity: lymphocytopenia (8%) and hyponatremia (8%). No dose-limiting toxicities occurred. In the AdCC cohort, six patients (60%) completed the four treatment cycles. Due to progressive disease, treatment was discontinued after two cycles in three patients (30%) and after one cycle in one patient (10%). No objective responses were observed (ORR: 0%). Three AdCC patients (30%) showed stable disease ≥ 6 months (7, 17 and 23 months). None of the two SDC patients completed the treatment: one patient deteriorated after the first cycle, while the other had progressive disease after two cycles. The high screen failure rate due to insufficient PSMA uptake resulted in premature closure of the SDC cohort. Dosimetry revealed low tumor-absorbed doses (median 0.07 Gy/GBq, range 0.001-0.63 Gy/GBq). Conclusions: [ 177 Lu]Lu-PSMA-I&T in AdCC and SDC patients was safe and generally well-tolerated. However, efficacy was limited, likely due to low tumor-absorbed doses. For SDC, [ 177 Lu]Lu-PSMA-I&T appears unfeasible due to insufficient PSMA uptake., Competing Interests: Competing Interests: NvR, MU, CD, SP, BP, AvEvG, MK, MK: nothing to declare. JN: has received research grants from ABX and Novartis, and has received consulting and teaching fees from ITM, POINT biopharma, CURIUM, Novartis and Bayer. CvH: has been member of advisory boards for Bayer, Bristol-Myers Squibb, Elevar, Ipsen, MSD and Regeneron, and has received research grants from Astra Zeneca, Bristol-Myers Squibb, MSD, Merck, Ipsen, Novartis and Sanofi., (© The author(s).)

Rationale: PSMA-targeting radioligand therapy (PSMA-RLT) has shown promise in metastatic castration-resistant prostate cancer (mCRPC), particularly in PSMA-avid tumours. However, predicting response remains challenging. Preclinical data suggests aberrant p53-signalling as a predictor of poor response. Methods: The patient population of this pre-planned retrospective cohort study consists of 96 patients with mCRPC who underwent treatment with PSMA-RLT and were molecularly profiled by whole-genome sequencing and or targeted next-generation sequencing. Response to PSMA-RLT was assessed per molecular subtype, including TP53 -mutational status. Results: Patients with TP53 loss-of-function alterations had a shorter median progression-free survival (3.7 versus 6.2 months, P <0.001), a lower median PSA change (-55% vs. -75%, P =0.012) and shorter overall survival from initiation of PMSA-RLT (7.6 vs. 13.9 months, P =0.003) compared to TP53 -wildtype patients. Pathogenic alterations in AR , MYC , BRCA1 , or BRCA2 as well as in genes linked to the PI3K or MAPK pathways or genes involved in homologous recombination repair, were not associated with response. Only lactate dehydrogenase was, alongside TP53 -status, significantly associated with response. Transcriptome analysis of 21 patients, identified six p53 signalling genes whose low expression was associated to a shorter progression-free survival ( P <0.05). Conclusion: TP53 loss-of-function may serve as a prognostic factor for PSMA-RLT outcomes in patients with mCRPC., Competing Interests: Competing Interests: Maarten J. van der Doelen: Research support: 'Bayer, Janssen-Cilag'. Travel support: 'Astellas'. James Nagarajah: Research support: 'ABX, Novartis'. Advisory role: 'ITM, POINT biopharma, CURIUM, Novartis, Bayer'. Inge M. van Oort: Advisory role: 'Bayer, Astellas, Janssen, MSD/AstraZeneca'. Research support: 'Astellas, Janssen, Bayer'. Jack. A. Schalken: Speaker honorarium: 'Astellas, Bayer'. Niven Mehra: Advisory role: 'Roche, MSD, BMS, Bayer, Astellas, Janssen'. Research support: 'Astellas, Janssen, Pfizer, Roche and Sanofi' Genzyme'. Travel support: 'Astellas, MSD'. The remaining authors declare no conflict of interest., (© The author(s).)

Background: Bone marrow toxicity in advanced prostate cancer patients who receive [ 177 Lu]Lu-PSMA-617 is a well-known concern. In early stage patients; e.g. low volume metastatic hormone sensitive prostate cancer (mHSPC) patients, prevention of late bone marrow toxicity is even more crucial due to longer life expectancy. To date, bone marrow dosimetry is primarily performed using blood sampling. This method is time consuming and does not account for possible active bone marrow uptake. Therefore other methodologies are investigated. We calculated the bone marrow absorbed dose for [ 177 Lu]Lu-PSMA-617 in mHSPC patients using SPECT/CT imaging and compared it to the blood sampling method as reference., Methods: Eight mHSPC patients underwent two cycles (3 and 6 GBq) of [ 177 Lu]Lu-PSMA-617 therapy. After each cycle, five time point (1 h, 1 day, 2 days, 3 days, 7 days) SPECT/CT was performed at kidney level. Bone marrow dosimetry was performed using commercial software by drawing ten 1.5 cm diameter spheres in the lowest ten vertebrae to determine the time-integrated activity. Simplified protocols using only 2 imaging time points and 3 vertebrae were also compared. Blood-based dosimetry was based on the blood sampling method according to the EANM guideline., Results: Mean bone marrow absorbed dose was significantly different (p < 0.01) for the imaging based method (25.4 ± 8.7 mGy/GBq) and the blood based method (17.2 ± 3.4 mGy/GBq), with an increasing absorbed dose ratio between both methods over time. Bland Altman analysis of both simplification steps showed that differences in absorbed dose were all within the 95% limits of agreement., Conclusion: This study showed that bone marrow absorbed dose after [ 177 Lu]Lu-PSMA-617 can be determined using an imaging-based method of the lower vertebrae, and simplified using 2 time points (1 and 7 days) and 3 vertebrae. An increasing absorbed dose ratio over time between the imaging-based method and blood-based method suggests that there might be specific bone marrow binding of [ 177 Lu]Lu-PSMA-617., (© 2024. The Author(s).)

Studies to evaluate and optimize [ 177 Lu]Lu-PSMA treatment focus primarily on individual patient data. A population pharmacokinetic (PK) dosimetry model was developed to explore the potential of using imaging data as input for population PK models and to characterize variability in organ and tumor uptake of [ 177 Lu]Lu-PSMA-617 in patients with low volume metastatic prostate cancer. Simulations were performed to identify the effect of dose adjustments on absorbed doses in salivary glands and tumors. A six-compartment population PK model was developed, consisting of blood, salivary gland, kidneys, liver, tumor, and a lumped compartment representing other tissue (compartment 1-6, respectively), based on data from 10 patients who received [ 177 Lu]Lu-PSMA-617 (2 cycles, ~ 3 and ~ 6 GBq). Data consisted of radioactivity levels (decay corrected) in blood and tissues (9 blood samples and 5 single photon emission computed tomography/computed tomography scans). Observations in all compartments were adequately captured by individual model predictions. Uptake into salivary glands was saturable with an estimated maximum binding capacity (B max ) of 40.4 MBq (relative standard error 12.3%) with interindividual variability (IIV) of 59.3% (percent coefficient of variation [CV%]). IIV on other PK parameters was relatively minor. Tumor volume was included as a structural effect on the tumor uptake rate constant (k 15 ), where a two-fold increase in tumor volume resulted in a 1.63-fold increase in k 15 . In addition, interoccasion variability on k 15 improved the model fit (43.5% [CV%]). Simulations showed a reduced absorbed dose per unit administered activity for salivary glands after increasing radioactivity dosing from 3 to 6 GBq (0.685 Gy/GBq vs. 0.421 Gy/GBq, respectively). All in all, population PK modeling could help to improve future radioligand therapy research., (© 2023 The Authors. CPT: Pharmacometrics & Systems Pharmacology published by Wiley Periodicals LLC on behalf of American Society for Clinical Pharmacology and Therapeutics.)

Background: Dosimetry in [ 177 Lu]Lu-PSMA therapy is a valuable tool to assess treatment efficacy and toxicity. This study aims to develop a clinically implementable protocol to determine the absorbed dose in organs and tumor lesions after [ 177 Lu]Lu-PSMA-617 therapy, by reducing the imaging time points and utilizing population-based kinetics with a single scan, with evaluation of its influence on the uncertainty in absorbed dose., Methods: Ten patients with metastatic hormone-sensitive prostate cancer received two cycles of [ 177 Lu]Lu-PSMA-617. Post-treatment imaging was performed at 1 h, 24 h, 48 h, 72 h and 168 h, consisting of three-bed positions SPECT/CT and a whole-body planar scan. Five-time point SPECT dosimetry was performed for lesions and organs with physiological uptake (kidneys, liver and salivary glands) and used as the reference standard. Absorbed dose values for various simplified protocols were compared to the reference standard., Results: Accurate lesion dosimetry is possible using one-time point SPECT imaging at 168 h, with an increase in uncertainty (20% vs. 14% for the reference standard). By including a second time point, uncertainty was comparable to the reference standard (13%). Organ dosimetry can be performed using a single SPECT at 24 h or 48 h. Dosimetry based on planar scans did not provide accurate dose estimations., Conclusion: Accurate lesion dosimetry in [ 177 Lu]Lu-PSMA therapy can be performed using a one- or two-time point protocol, making dosimetry assessments more suitable for routine clinical implementation, although dosimetry based om multiple time points is more accurate. Clinical trial registration This study was approved by the Medical Review Ethics Committee Region Arnhem-Nijmegen on January 23, 2018 and was registered on clinicaltrials.gov (NCT03828838)., (© 2023. The Author(s).)

Background: Prostate-specific membrane antigen (PSMA)-directed radioligand therapy (RLT) is a novel treatment for patients with castration-resistant prostate cancer (CRPC). Given the mode of action, patients in an earlier disease stage, such as hormone-sensitive prostate cancer (HSPC), are also likely to benefit from [ 177 Lu]Lu-PSMA- ( 177 Lu-PSMA) or [ 225 Ac]Ac-PSMA-radioligand treatment ( 225 Ac-PSMA). In this retrospective study, we analyzed the safety and efficacy of PSMA-RLT in early-stage and hormone-sensitive metastatic prostate cancer patients., Methods: A retrospective study was performed in patients who received 177 Lu-PSMA and/or 225 Ac-PSMA with early-stage metastatic prostate cancer. The primary outcome parameter evaluated in this study was the progression-free survival (PFS) after PSMA-RLT and toxicity according to the Common Terminology Criteria for Adverse Events. Secondary outcome parameters were prostate-specific antigen (PSA) response and the date of onset of CRPC state., Results: In total, 20 patients were included of which 18 patients received 177 Lu-PSMA radioligand and two patients received tandem treatment with both 177 Lu-PSMA and 225 Ac-PSMA radioligands. Patients received a median of 2 treatment cycles (range 1-6) and a median activity of 6.2 GBq 177 Lu-PSMA per cycle (interquartile range (IQR) 5.2-7.4 GBq). PSMA-RLT was overall well-tolerated. The most common grade 1-2 side effects were xerostomia ( n = 6) and fatigue ( n = 8), which were only temporarily reported. One patient that received 225 Ac-PSMA developed grade 3-4 bone marrow toxicity. The median PFS was 12 months (95% confidence interval (CI), 4.09-19.9 months). Seventeen (85%) patients had a ≥50% PSA response following PSMA-RLT. One patient developed CRPC 9 months following PSMA-RLT., Conclusions: In this small cohort study, PSMA-RLT appeared safe and showed encouraging efficacy for (metastasized) early-stage and hormone-sensitive prostate cancer patients. Prospective studies are awaited and should include long-term follow-up.

177 Lu-PSMA-617 radioligand therapy is a novel treatment for end-stage prostate cancer, which could also be applied to patients with hormone-sensitive prostate cancer with high expression levels of prostate-specific membrane antigen (PSMA). In this perspective, we review the recent results of toxicity, radiation doses, and treatment effect of 177 Lu-PSMA in patients with low volume metastatic hormone-sensitive prostate cancer. Moreover, we present long-term follow-up data, such as toxicity and time without androgen deprivation therapy (ADT), of the patients who participated in this trial. Overall, 177 Lu-PSMA appeared to be a feasible and safe treatment modality in this setting, as well as in long-term follow-up. We observed that men with a prostate-specific antigen (PSA) response of more than 50% seemed to especially benefit from this therapy by postponing ADT and thus preserving the quality of life., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Privé, Muselaers, van Oort, Janssen, Peters, van Gemert, Uijen, Schilham, Sedelaar, Westdorp, Mehra, Gotthardt, Barentsz, Gerritsen, Witjes and Nagarajah.)

Positron emission tomography (PET) of prostate-specific membrane antigen (PSMA) allows for accurate diagnosis and staging of prostate cancer (PCa). Compared to other PSMA PET tracers available, [18F]PSMA-1007 is predominantly excreted via the hepatobiliary tract resulting in low renal excretion which improves evaluation of the pelvic area. However, some patients do show high urinary uptake of [18F]PSMA-1007. The present study aimed to investigate this sudden high urinary uptake of [18F]PSMA-1007 by evaluating [18F]PSMA-1007 PET scans from PCa patients. In this single-center retrospective study, patients that underwent [18F]PSMA-1007 PET imaging between July 2018 and January 2021 were included. Data regarding the individual patient characteristics, scan acquisition and batch production were analyzed. To determine the urinary excretion of [18F]PSMA-1007, a region of interest was drawn in the bladder, and standardized uptake values (SUVs) were calculated and compared to SUVs in the prostate. An SUVmax of >10 was considered high urinary excretion, an SUVmax 7.5−10 intermediate and an SUVmax < 7.5 low urinary excretion. A total of 344 patients underwent [18F]PSMA-1007 PET/CT imaging, with 37 patients receiving three or more [18F]PSMA-1007 PET/CT scans. The mean SUVmean and SUVmax of the bladder were 3.9 (SD 2.9) and 5.9 (SD 4.2), respectively. Fourteen percent of patients showed high urinary uptake of [18F]PSMA-1007. Twelve of the thirty-seven patients (32.4%) that had multiple scans showed a varying urinary uptake of [18F]PSMA-1007 per PSMA PET/CT scan. In terms of patient characteristics, risk factors, medication and blood laboratory results, no significant influencing variables were found. Nor was there a difference observed in the batch size and the mean radiochemical purity of PSMA-1007 for high- and low-excreting patients. However, the bladder volume affected the mean SUVmax in the bladder significantly, with higher SUVs in lower bladder volumes. In this study, we observed that a higher SUV in the urinary tract seemed to occur in patients with low bladder volume. A prospective study is needed to corroborate this hypothesis.

Accurate assessment of lymph node (LN) metastases in prostate cancer (PCa) patients is critical for prognosis and patient management. Both prostate-specific membrane antigen (PSMA) PET/CT and ferumoxtran-10 nanoparticle-enhanced MRI (nano-MRI) are imaging modalities with high potential to identify LN metastases in PCa patients. The aim of this study was to compare the results of these imaging technologies in terms of characteristics and anatomic localization of suspicious LNs in order to assess the feasibility of their complementary use for imaging in PCa patients. Methods: In total, 45 patients with either primary PCa ( n = 8) or recurrence ( n = 36) were included in this retrospective study. All patients underwent both 68 Ga-PSMA PET/CT and nano-MRI between October 2015 and July 2017 within 3 wk. Both scans were performed at the same institution according to local clinical protocols. All scans were analyzed independently by experienced nuclear medicine physicians and radiologists. The size, anatomic location, and level of suspicion were determined for all visible LNs. Subsequently, the findings from 68 Ga-PSMA PET/CT and nano-MRI were compared without respect to a reference standard. Results: In total, 179 suspicious LNs were identified. Significantly more suspicious LNs per patient were detected by nano-MRI ( P < 0.001): 160 were identified in 33 patients by nano-MRI, versus 71 in 25 patients by 68 Ga-PSMA PET/CT. Of all suspicious LNs, 108 were identified only by nano-MRI (60%), 19 (11%) only by 68 Ga-PSMA PET/CT, and 52 (29%) by both methods. The mean size of the suspicious LNs as identified by nano-MRI was significantly smaller (5.3 mm) than that by 68 Ga-PSMA PET/CT (6.0 mm; P = 0.006). The median level of suspicion did not differ significantly. Both modalities identified suspicious LNs in all anatomic regions of the pelvis. Conclusion: Both modalities identified suspicious LNs that were missed by the other. Both modalities identified suspicious LNs in all anatomic regions of the pelvis; however, nano-MRI appeared to be superior in detecting smaller suspicious LNs. These findings suggest that nano-MRI has a potential role as a complement to PSMA PET/CT. However, since the clinical implications of the different results are not well established yet, further investigation of this complementary use is encouraged., (© 2021 by the Society of Nuclear Medicine and Molecular Imaging.)

Purpose: [ 177 Lu]Lu-PSMA-617 radioligand therapy ( 177 Lu-PSMA) is a novel treatment for metastatic castration-resistant prostate cancer (mCRPC), which could also be applied to patients with metastatic hormone-sensitive prostate cancer (mHSPC) with PSMA expression. In this prospective study (NCT03828838), we analyzed toxicity, radiation doses, and treatment effect of 177 Lu-PSMA in pateints with low-volume mHSPC., Patients and Methods: Ten progressive patients with mHSPC following local treatment, with a maximum of ten metastatic lesions on [ 68 Ga]Ga-PSMA-11 PET/diagnostic-CT imaging (PSMA-PET) and serum PSA doubling time <6 months received two cycles of 177 Lu-PSMA. Whole-body single-photon emission CT/CT (SPECT/CT) and blood dosimetry was performed to calculate doses to the tumors and organs at risk (OAR). Adverse events (AE), laboratory values (monitoring response and toxicity), and quality of life were monitored until week 24 after cycle 2, the end of study (EOS). All patients underwent PSMA-PET at screening, 8 weeks after cycle 1, 12 weeks after cycle 2, and at EOS., Results: All patients received two cycles of 177 Lu-PSMA without complications. No treatment-related grade III-IV adverse events were observed. According to dosimetry, none of the OAR reached threshold doses for radiation-related toxicity. Moreover, all target lesions received a higher radiation dose than the OAR. All 10 patients showed altered PSA kinetics, postponed androgen deprivation therapy, and maintained good quality of life. Half of the patients showed a PSA response of more than 50%. One patient had a complete response on PSMA-PET imaging until EOS and two others had only minimal residual disease., Conclusions: 177 Lu-PSMA appeared to be a feasible and safe treatment modality in patients with low-volume mHSPC., (©2021 American Association for Cancer Research.)

Background: In recent years, there is increasing evidence showing a beneficial outcome (e.g. progression free survival; PFS) after metastases-directed therapy (MDT) with external beam radiotherapy (EBRT) or targeted surgery for oligometastatic hormone sensitive prostate cancer (oHSPC). However, many patients do not qualify for these treatments due to prior interventions or tumor location. Such oligometastatic patients could benefit from radioligand therapy (RLT) with 177 Lu-PSMA; a novel tumor targeting therapy for end-stage metastatic castration-resistant prostate cancer (mCRPC). Especially because RLT could be more effective in low volume disease, such as the oligometastatic status, due to high uptake of radioligands in smaller lesions. To test the hypothesis that 177 Lu-PSMA is an effective treatment in oHSPC to prolong PFS and postpone the need for androgen deprivation therapy (ADT), we initiated a multicenter randomized clinical trial. This is globally, the first prospective study using 177 Lu-PSMA-I&T in a randomized multicenter setting., Methods & Design: This study compares 177 Lu-PSMA-I&T MDT to the current standard of care (SOC); deferred ADT. Fifty-eight patients with oHSPC (≤5 metastases on PSMA PET) and high PSMA uptake (SUVmax > 15, partial volume corrected) on 18 F-PSMA PET after prior surgery and/or EBRT and a PSA doubling time of < 6 months, will be randomized in a 1:1 ratio. The patients randomized to the interventional arm will be eligible for two cycles of 7.4GBq 177 Lu-PSMA-I&T at a 6-week interval. After both cycles, patients are monitored every 3 weeks (including adverse events, QoL- and xerostomia questionnaires and laboratory testing) at the outpatient clinic. Twenty-four weeks after cycle two an end of study evaluation is planned together with another 18 F-PSMA PET and (whole body) MRI. Patients in the SOC arm are eligible to receive 177 Lu-PSMA-I&T after meeting the primary study objective, which is the fraction of patients who show disease progression during the study follow up. A second primary objective is the time to disease progression. Disease progression is defined as a 100% increase in PSA from baseline or clinical progression., Discussion: This is the first prospective randomized clinical study assessing the therapeutic efficacy and toxicity of 177 Lu-PSMA-I&T for patients with oHSPC., Trial Registration: Clinicaltrials.gov identifier: NCT04443062 .