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Background Lutetium 177 [ 177 Lu]Lu-PSMA-617 ( 177 Lu-PSMA-617) is a prostate-specific membrane antigen (PSMA)-targeted radioligand therapy for metastatic castration-resistant prostate cancer (mCRPC). Quantitative PSMA PET/CT analysis could provide information on 177 Lu-PSMA-617 treatment benefits. Purpose To explore the association between quantitative baseline gallium 68 [ 68 Ga]Ga-PSMA-11 ( 68 Ga-PSMA-11) PET/CT parameters and treatment response and outcomes in the VISION trial. Materials and Methods This was an exploratory secondary analysis of the VISION trial. Eligible participants were randomized (June 2018 to October 2019) in a 2:1 ratio to 177 Lu-PSMA-617 therapy (7.4 GBq every 6 weeks for up to six cycles) plus standard of care (SOC) or to SOC only. Baseline 68 Ga-PSMA-11 PET parameters, including the mean and maximum standardized uptake value (SUV mean and SUV max ), PSMA-positive tumor volume, and tumor load, were extracted from five anatomic regions and the whole body. Associations of quantitative PET parameters with radiographic progression-free survival (rPFS), overall survival (OS), objective response rate, and prostate-specific antigen response were investigated using univariable and multivariable analyses (with treatment as the only other covariate). Outcomes were assessed in subgroups based on SUV mean quartiles. Results Quantitative PET parameters were well balanced between study arms for the 826 participants included. The median whole-body tumor SUV mean was 7.6 (IQR, 5.8-9.9). Whole-body tumor SUV mean was the best predictor of 177 Lu-PSMA-617 efficacy, with a hazard ratio (HR) range of 0.86-1.43 for all outcomes (all P < .001). A 1-unit whole-body tumor SUV mean increase was associated with a 12% and 10% decrease in risk of an rPFS event and death, respectively. 177 Lu-PSMA-617 plus SOC prolonged rPFS and OS in all SUV mean quartiles versus SOC only, with no identifiable optimum among participants receiving 177 Lu-PSMA-617. Higher baseline PSMA-positive tumor volume and tumor load were associated with worse rPFS (HR range, 1.44-1.53 [ P < .05] and 1.02-1.03 [ P < .001], respectively) and OS (HR range, 1.36-2.12 [ P < .006] and 1.04 [ P < .001], respectively). Conclusion Baseline 68 Ga-PSMA-11 PET/CT whole-body tumor SUV mean was the best predictor of 177 Lu-PSMA-617 efficacy in participants in the VISION trial. Improvements in rPFS and OS with 177 Lu-PSMA-617 plus SOC were greater among participants with higher whole-body tumor SUV mean , with evidence for benefit at all SUV mean levels. ClinicalTrials.gov identifier: NCT03511664 Published under a CC BY 4.0 license. Supplemental material is available for this article.

Background and Objective: [ 177 Lu]Lu-PSMA-617 ( 177 Lu-PSMA-617) plus the standard of care (SoC) significantly improved overall survival and radiographic progression-free survival versus SoC alone in patients with prostate-specific membrane antigen (PSMA)-positive metastatic castration-resistant prostate cancer in the VISION trial. We evaluated the safety of additional cycles of 177 Lu-PSMA-617 and the impact of longer observation time for patients receiving 177 Lu-PSMA-617 plus SoC., Methods: VISION was an international, open-label study. Patients were randomised 2:1 to receive 177 Lu-PSMA-617 plus SoC or SoC alone. The incidence of treatment-emergent adverse events (TEAEs) was assessed in prespecified subgroups of patients who received ≤4 cycles versus 5-6 cycles of treatment and during each cycle of treatment. The TEAE incidence was also adjusted for treatment exposure to calculate the incidence per 100 patient-treatment years of observation. This analysis was performed for the first occurrence of TEAEs., Key Findings and Limitations: The any-grade TEAE incidence was similar in cycles 1-4 and cycles 5-6. TEAE frequency was similar across all cycles of 177 Lu-PSMA-617 treatment. No additional safety concerns were reported for patients who received >4 cycles. The exposure-adjusted safety analysis revealed that the overall TEAE incidence was similar between arms, but distinct trends for different TEAE types were noted and the incidence of events associated with 177 Lu-PSMA-617 remained higher in the 177 Lu-PSMA-617 arm., Conclusions and Clinical Implications: Longer exposure to 177 Lu-PSMA-617 plus SoC was not associated with a higher toxicity risk, and the extended time for safety observation could account for the higher TEAE incidence in comparison to SoC alone. The findings support a favourable benefit-risk profile for 6 cycles of 177 Lu-PSMA-617 in this setting and the use of up to 6 cycles of 177 Lu-PSMA-617 in patients who are clinically benefiting from and tolerating this therapy., Patient Summary: For patients with metastatic prostate cancer no longer responding to hormone therapy, an increase in the number of cycles of treatment with a radioactive compound called 177 Lu-PSMA-617 from four to six had no additional adverse side effects., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Metastatic castration-resistant prostate cancer remains fatal despite recent advances. Prostate-specific membrane antigen (PSMA) is highly expressed in metastatic castration-resistant prostate cancer. Lutetium-177 ( 177 Lu)-PSMA-617 is a radioligand therapy that delivers beta-particle radiation to PSMA-expressing cells and the surrounding microenvironment., Methods: We conducted an international, open-label, phase 3 trial evaluating 177 Lu-PSMA-617 in patients who had metastatic castration-resistant prostate cancer previously treated with at least one androgen-receptor-pathway inhibitor and one or two taxane regimens and who had PSMA-positive gallium-68 ( 68 Ga)-labeled PSMA-11 positron-emission tomographic-computed tomographic scans. Patients were randomly assigned in a 2:1 ratio to receive either 177 Lu-PSMA-617 (7.4 GBq every 6 weeks for four to six cycles) plus protocol-permitted standard care or standard care alone. Protocol-permitted standard care excluded chemotherapy, immunotherapy, radium-223 ( 223 Ra), and investigational drugs. The alternate primary end points were imaging-based progression-free survival and overall survival, which were powered for hazard ratios of 0.67 and 0.73, respectively. Key secondary end points were objective response, disease control, and time to symptomatic skeletal events. Adverse events during treatment were those occurring no more than 30 days after the last dose and before subsequent anticancer treatment., Results: From June 2018 to mid-October 2019, a total of 831 of 1179 screened patients underwent randomization. The baseline characteristics of the patients were balanced between the groups. The median follow-up was 20.9 months. 177 Lu-PSMA-617 plus standard care significantly prolonged, as compared with standard care, both imaging-based progression-free survival (median, 8.7 vs. 3.4 months; hazard ratio for progression or death, 0.40; 99.2% confidence interval [CI], 0.29 to 0.57; P<0.001) and overall survival (median, 15.3 vs. 11.3 months; hazard ratio for death, 0.62; 95% CI, 0.52 to 0.74; P<0.001). All the key secondary end points significantly favored 177 Lu-PSMA-617. The incidence of adverse events of grade 3 or above was higher with 177 Lu-PSMA-617 than without (52.7% vs. 38.0%), but quality of life was not adversely affected., Conclusions: Radioligand therapy with 177 Lu-PSMA-617 prolonged imaging-based progression-free survival and overall survival when added to standard care in patients with advanced PSMA-positive metastatic castration-resistant prostate cancer. (Funded by Endocyte, a Novartis company; VISION ClinicalTrials.gov number, NCT03511664.)., (Copyright © 2021 Massachusetts Medical Society.)

Background: [ 177 Lu]-PSMA-617 (Lu-PSMA) therapy is a promising therapeutic option for end-stage prostate cancer patients. Early treatment response at the first restaging after two therapy cycles might correlate with high treatment efficacy and long overall survival (OS). Therefore, the aim of this study was to evaluate whether early reduction in tumor volume is a positive prognosticator for OS. To this end, PSMA PET prior to therapy (baseline) and at first restaging after two therapy cycles (interim; i.e., 12 weeks) were compared. Methods: Patients with metastatic castration-resistant prostate cancer who received Lu-PSMA therapy were reviewed for this analysis. All patients with available baseline and interim [ 68 Ga]-PSMA-11 PET/CT were included in this analysis (n = 33). All PSMA avid metastases in baseline and interim PETs were semi-automatically segmented. The average PSMA expression (mean SUV max of all metastases), total tumor volume (PSMA-TV) and TLQ (quotients of tumor volume and SUV mean summed over all metastases) were quantified at baseline and interim timepoints. Response in PSMA-TV was assumed when a decline > 30% was present. OS and biochemical response were available for all patients. Results: Baseline PSMA-TV was a statistically significant prognosticator of OS (HR = 1.618 95%CI: 1.117 - 2.343, p = 0.011). Reduction in PSMA-TV was not a statistically significant positive prognosticator of OS in the total cohort (HR = 0.829 95%CI: 0.559 - 1.230, p = 0.352). Likewise, there was no statistical difference in survival time comparing patients with PSMA-TV response to those without (13.2 vs. 15.6 months, p = 0.1). In the subgroup of patients with PSMA-TV response, mean SUV max was a statistically significant prognosticator of OS (binarized by median; HR = 0.15; 95%CI: 0.03 - 0.83; p < 0.05). If patients with low PSMA expression at baseline were excluded from the analysis, reduction in PSMA-TV became a positive prognosticator of OS in uni- and multivariable Cox regression (HR = 0.290; 95%CI: 0.108 - 0.782; p = 0.015). Conclusion: PSMA-TV reduction was a positive prognosticator of OS only if patients with low PSMA expression were excluded. This might indicate that the PSMA-PETs of patients with low PSMA expression may not be suited for assessing PSMA-TV reduction. Future studies investigating the interplay of PSMA-TV and low PSMA expression response are warranted., Competing Interests: Competing Interests: The authors have declared that no competing interest exists., (© The author(s).)

Rationale: PSMA-PET-CT enables measuring molecular expression of prostate-specific membrane antigen (PSMA) in vivo , which is the target molecule of 177 Lu-PSMA-617 (Lu-PSMA) therapy. However, the correlation of PSMA expression and overall survival (OS) in patients treated with Lu-PSMA therapy is currently unclear; especially with regard to coexistence of high and low PSMA expressing metastases. To this end, this retrospective single arm study elucidates the correlation of PSMA expression and overall survival in patients treated with Lu-PSMA therapy. Additionally, PET based criteria to define low PSMA expression were explored. Methods: Eighty-five patients referred to Lu-PSMA therapy were included in the analysis. Pretherapeutic 68 Ga-PSMA-PET-CT scans were available for all patients. SUV max of the highest PSMA expressing metastasis (PSMA max ), SUV max of the lowest PSMA expressing metastasis (PSMA min ), and average SUV max of all metastases (PSMA average ) amongst other PET parameters were measured for each patient. A log-rank cutoff-finder was used to determine low (lowPSMA average ) and high (highPSMA average ) average PSMA expression as well as low (lowPSMA min ) and high (highPSMA min ) minimal PSMA expression. Results: PSMA average was a significant prognosticator of overall survival in contrast to PSMA max (HR: 0.959; p = 0.047 vs. HR: 0.992; p = 0.231). Optimal log rank cut-offs were: PSMA average = 14.3; PSMA min = 10.2. Patients with low average PSMA expression (lowPSMA average ) had significantly shorter survival compared to those with high average expression (highPSMA average ) (5.3 vs. 15.1 months; p < 0.001; HR: 3.738, 95%CI = 1.953-7.154; p < 0.001). Patients with low PSMA expressing metastases (lowPSMA min ) had shorter survival compared to those without a low PSMA expressing metastasis (highPSMA min ) (p = 0.003; 7.9 months vs. 21.3; HR: 4.303, 95%CI = 1.521-12.178; p = 0.006). Patients that were classified as highPSMA average but with lowPSMA min had an intermediate overall survival (11.4 months; longer compared to lowPSMA average , 5.3 months, p = 0.002; but shorter compared to highPSMA min , 21.3 months, p = 0.02). Conclusion: Low average PSMA expression is a negative prognosticator of overall survival. Absence of low PSMA expressing metastases is associated with best overall survival and the maximum PSMA expression seems not suited to prognosticate overall survival. Low PSMA expression might therefore be a negative prognosticator for the outcome of patients treated with Lu-PSMA therapy. Future studies are warranted to elucidate the degree of low PSMA expression tolerable for Lu-PSMA therapy., (© The author(s).)

Rationale: Lu-177-PSMA-617 radioligand therapy (RLT) is currently under approval for treatment of metastatic castration resistant prostate cancer (mCRPC) patients with late stage disease. However, previous studies demonstrated both heterogeneity of prostate specific membrane antigen (PSMA) expression, as well as response to PSMA treatment among mCRPC patients. Thus, there is an unmet need for identifying predictive parametres prior or under PSMA-RLT treatment. We therefore aimed to correlate several clinical and molecular parameters with response to PSMA treatment in a cohort of mCRPC patients undergoing PSMA RLT followed by a detailed analysis of promising candidates. Methods: Nineteen patients, median age 68.8 years (range: 56.9 - 83.3) with mCRPC were included in this study. We performed baseline analysis of clinical parameters based on PSMA PET/CT, (metabolic tumor volume (MTV), total tumor volume (TTV)), serum PSA, ALP, LDH and gene expression analysis of circulating tumor cells (expression of AR full length (AR-FL), AR splice variant 7 (AR-V7), PSA and PSMA) as well as common markers for neuroendocrine differentiation (NED). Results: Patients presented with bone, lymph node, and visceral metastases (89%, 68%, and 21%, respectively). All patients were pretreated with docetaxel, either abiraterone or enzalutamide, or both. Biochemical response in terms of PSA decline ≥50 or ≥30% was observed in 42% and 63%, respectively. There were significant correlations between PSA and PSMA mRNA expression, as well as tumor volumes (both MTV and TTV), AR-FL and AR-V7 mRNA expression. However, there was no correlation with response to PSMA treatment. Furthermore, none of these parameters was significantly correlated with baseline serum PSA values. Common NED markers were shown to be specifically high expressed and revealed impact on OS independent from AR-V7 gene expression. Conclusion: We demonstrate that AR-FL and its splice variant AR-V7 might serve as prognostic biomarkers displaying high tumor burden in mCRPC patient prior to PSMA-RLT. Contrary, PSMA, which has been discussed as a biomarker for PSMA targeted treatment, does not display strong prognostic ability - at least on the mRNA level. Surprisingly, none of these parameters correlates to response to PSMA treatment. In contrast, commom NED markers such as SYP and ENO2 as well as FOXA1 expression level seem to predict OS, but not PFS, more reliably. We admit that a limitation of our study is the focus on mRNA expression of potential biomarkers only. Further investigations analyzing the potential role of protein expression of these markers are therefore warranted., Competing Interests: Competing Interests: The authors have declared that no competing interest exists., (© The author(s).)

Background: Based on significant progress in recent years, metastatic castration-resistant prostate cancer (mCRPC) patients can be treated better and better. The medications include androgen signaling inhibitors, chemotherapy, 223 Ra, and sipuleucel-T. Most patients treated with these agents will still develop primary or secondary resistance against any given drug. The 177 Lutetium-PSMA radioligand therapy ( 177 Lu-PSMA-RLT) represents a good reserve option and can be used within compassionate use provisions demonstrating promising efficacy in the majority of patients in Germany., Objectives: Establishment of status quo of 177 Lu-PSMA-RLT in mCRPC in 2020., Materials and Methods: Presentation of the therapy landscape in mCRPC and the current evidence on 177 Lu-PSMA-RLT after PubMed based literature search., Results: Several larger retrospective studies and the first prospective trials on 177 Lu-PSMA-RLT show premature but encouraging evidence on 177 Lu-PSMA-RLT to be a promising new option in mCRPC patients. The toxicity profile seems to be favorable. The phase III trial VISION aims to provide evidence for the approval of 177 Lu-PSMA-RLT in combination with abiraterone or enzalutamide in patients having been pretreated with enzalutamide or abiraterone and docetaxel., Conclusions: Despite the promising preliminary results of 177 Lu-PSMA-RLT, the efficacy results of VISION need to be awaited prior to using the therapy outside of compassionate use provisions.

The aim of this study was to evaluate the efficacy of 177 Lu-prostate-specific membrane antigen (PSMA)-617 ( 177 Lu-PSMA) and selective internal radiation therapy (SIRT) for the treatment of liver metastases of castration-resistant prostate cancer. Methods: Safety and survival of patients with metastatic castration-resistant prostate cancer and liver metastases assigned to 177 Lu-PSMA alone ( n = 31) or in combination with SIRT ( n = 5) were retrospectively analyzed. Additionally, a subgroup ( n = 10) was analyzed using morphologic and molecular response criteria. Results: Median estimated survival was 5.7 mo for 177 Lu-PSMA alone and 8.4 mo for combined sequential 177 Lu-PSMA and SIRT. 177 Lu-PSMA achieved discordant therapy responses with both regressive and progressive liver metastases in the same patient (best vs. worst responding metastases per patient: -35% vs. +63% diameter change; P < 0.05). SIRT was superior to 177 Lu-PSMA for the treatment of liver metastases (0% vs. 56% progression). Conclusion: The combination of 177 Lu-PSMA and SIRT is efficient and feasible for the treatment of advanced prostate cancer. 177 Lu-PSMA alone seems to have limited response rates in the treatment of liver metastases., (© 2020 by the Society of Nuclear Medicine and Molecular Imaging.)

The purpose of this study was to identify previous treatments and biomarker profile features that prognosticate overall survival (OS) in patients with mCRPC receiving 177 Lu-PSMA-617. Methods: 109 mCRPC patients treated with a median of 3 cycles of 177 Lu-PSMA-617 were included. Data were analyzed according to OS as well as PSA response patterns with regard to prior therapies, laboratory biomarkers and metastatic extent in univariate as well as multivariate Cox's proportional hazards models. PSA decline was assessed using the lowest PSA levels after the first cycle of therapy (initial PSA response) and during the entire observation period (best PSA response). Results: In total, 54 patients (49.5%) died during the observation period. First and second line chemotherapy were performed in 85% and 26%, and Abiraterone and Enzalutamide were administered in 83% and 85%, respectively. Any initial PSA decline occurred in 55% while 25% showed a PSA decline of ≥50%. The median estimated OS was 9.9 months (95% CI: 7.2-12.5) for all patients. Any initial decline of PSA was associated with significantly prolonged OS (15.5 vs. 5.7 months, p = 0.002). Second line cabazitaxel chemotherapy (6.7 vs. 15.7 months, p = 0.002) and presence of visceral metastases (5.9 vs. 16.4 months, p <0.001) were associated with shorter OS. Only visceral metastases remained significant in a multivariate analysis. Conclusion: 177 Lu-PSMA-617 is an effective therapy for patients with mCRPC. However, the present data indicate that its beneficial effects on OS are strongly influenced by pretreatment (history of second line chemotherapy with cabazitaxel) and the presence of visceral metastases at onset of 177 Lu-PSMA-617 treatment., Competing Interests: Competing Interests: The University of Münster received consulting fees from ABX GmbH, Radeberg, Germany for K.R. and M.B. Additionally K.R. is scientific consultant/ advisor of ABX GmbH. The authors declare they have no conflict of interest according to the subject and matter of the present article.

Radiolabeled ligands targeting prostate-specific membrane antigen (PSMA) are currently being established. Prostate-specific membrane antigen radioligand therapy with Lu-PSMA-617 is a promising treatment in metastasized castration-resistant prostate cancer with high efficacy and safety and seems to prolong progression-free survival and overall survival. We present Ga-PSMA PET/CT images during and after 2 therapy courses, including each 4 cycles of Lu-PSMA-617, and prostate-specific antigen-level history of a 77-year-old heavily pretreated patient with metastasized castration-resistant prostate cancer.

Purpose: Radioligand therapy (RLT) using Lutetium-177 labeled PSMA-617 (Lu-PSMA) ligand is a new therapeutic option for salvage therapy in heavily pretreated patients with metastatic castration resistant prostate cancer. The aim of this retrospective study was to analyze response in patients receiving 3 cycles of Lu-PSMA., Methods: Seventy-one patients (median age: 72 years; range 44-87) received 3 cycles of RLT with Lu-PSMA (mean administered activity: 6.016 ± 0.543 GBq) every 8 weeks. Response was evaluated using serum PSA levels and a PSA decline ≥50% was considered as biochemical response. Additionally, any PSA decline after the first cycle was evaluated for further therapy effects after the second and third cycle., Results: A total of 213 cycles were performed in 71 patients. Data for response and adverse events were available for all patients. A PSA decline ≥50% and some PSA decline occurred in 56% and 66% of the patients. Of 30 patients with a PSA response after the first cycle, 28 remained responders and 12/41 of non-responders responded to further therapy cycles., Conclusion: RLT with Lu-177-PSMA-617 shows respectable response rates. In this retrospective analysis, a relevant number of patients showed a delayed response, even if they did not respond to the first cycle of the therapy.

Aim: Our aim was to evaluate overall survival and parameters prognosticating longer survival in a large and homogeneous group of patients treated with 177 Lu-PSMA-617 radioligand therapy with heavily pretreated advanced metastatic castration resistant prostate cancer., Methods: A total of 104 patients were treated with 351 cycles of 177 Lu-PSMA-617. Prostate specific antigen (PSA) changes after the first cycle of therapy were documented prior to a second cycle. Patients were followed-up for overall survival (OS). Any PSA decline, PSA decline ≥50%, initial PSA, alkaline phosphatase (ALP), lactate dehydrogenase (LDH), visceral metastases and cumulative injected activity were analyzed and evaluated according to OS. Multivariable analysis with parameters with a p-value ≤0.05 in univariate analysis was performed, additionally adjusting for age and presence of visceral metastases., Results: A total of 51 patients (49%) died during the observation period. The majority of patients (97%) presented with bone metastases, 77% with lymph node metastases and 32% with visceral metastases. All patients were treated with at least one line of chemotherapy. Either abiraterone or enzalutamide had been given in 100% of the patients. Any PSA decline occurred in 70 (67%) and a PSA decline ≥50% in 34 (33%) of patients after the first cycle. The median OS was 56.0 weeks (95%CI: 50.5-61.5). Initial PSA decline ≥50%, initial LDH, visceral metastases, second line chemotherapy or prior radium-223 did not have an effect on survival, whereas any initial PSA decline, initial ALP <220 U/L and cumulative injected activity ≥18.8 GBq were associated with a longer survival. A step-by-step analysis revealed a PSA decline ≥20.87% as the most noticeable cut-off prognosticating longer survival, which remained an independent prognosticator of improved OS in the multivariate analysis., Conclusion: 177 Lu-PSMA-617 RLT is a new effective therapeutic and seems to prolong survival in patients with advanced mCRPC pretreated with chemotherapy, abiraterone and/or enzalutamide.

Background: Despite significant progress in the treatment of metastatic castration-resistant prostate cancer (mCRPC) in recent years (including agents targeting androgen receptor signaling, chemotherapy, and 223 Ra), most of these patients still succumb to prostate cancer. Recently, 177 lutetium prostate-specific membrane antigen radioligand therapy ( 177 Lu-PSMA-RLT) has been increasingly used within compassionate use provisions in these patients in Germany and showed promising efficacy., Objectives: Establishment of the current position of 177 Lu-PSMA-RLT in mCRPC in 2017., Materials and Methods: Presentation of the therapy landscape in mCRPC and the current challenges within treatment and survey of the available data on 177 Lu-PSMA-RLT after PubMed-based research., Results: In several larger retrospective studies, 177 Lu-PSMA-RLT seems to be an encouraging new option with the potential to extend overall survival while displaying a favorable toxicity profile., Conclusions: Prospective trials are urgently needed to confirm these encouraging results found in retrospective analyses with 177 Lu-PSMA-RLT in the treatment of mCRPC.

Purpose: Radioligand therapies targeting prostate-specific membrane antigen (PSMA) have been established for the treatment of metastasized castration-resistant prostate cancer (mCRPC) in the last decade and show promising response rates and a favourable toxicity profile. The aim of this study was to evaluate the overall survival (OS) and to identify parameters predicting outcome in mCRPC patients treated with 177 Lu-PSMA-617., Methods: Between December 2014 and January 2017, 59 consecutive patients (median age 72 years; interquartile range, (IQR, 66-76 years) with mCRPC, who had been treated with at least one next-generation antihormonal drug as well as chemotherapy, were included in this study. Biochemical response was evaluated using Prostate Cancer Working Group 3 (PCWG3) criteria. Survival was evaluated using Kaplan-Meier estimates and Cox regression proportional hazards model. Toxicity was assessed using Common Toxicity Criteria for Adverse Events (CTCAE). The study was approved by the local ethics committee., Results: The 59 patients were treated with a total of 159 cycles (median 3 cycles, range 1-7) of 177 Lu-PSMA-617 (median dose 6.11 GBq, IQR 5.9-6.3 GBq). The median follow-up was 24 weeks (IQR 15-36 weeks). Follow-up data for at least 12 weeks (PCWG3) were available in 76% (45) of the patients. For outcome results data from all patients treated with at least one cycle were analysed. A decline in prostate-specific antigen (PSA) of ≥50% occurred in 53%, and a decline in PSA of any amount in 91% of patients. The estimated median OS was 32 weeks. An initial alkaline phosphatase (ALP) level <220 U/L and a PSA decline after the first cycle were associated with a longer OS (56 vs. 28 weeks, p < 0.01, and 56 vs. 29 weeks, p = 0.04, respectively). The median estimated PSA progression-free survival (PPFS) was 18 weeks. Only ALP level <220 U/L was significantly associated with a longer PPFS (41 vs. 18 weeks, p < 0.01)., Conclusions: A PSA decline after the first cycle of 177 Lu-PSMA-617 and an initial ALP level <220 U/L were predictors of a longer OS in patients with end-stage mCRPC. An ALP level <220 U/L was additionally associated with a longer PPFS.

Recently radiolabeled ligands targeting prostate specific membrane antigen (PSMA) have been introduced for diagnostics and treatment of prostate cancer. Labeled with Lutetium, PSMA radioligand therapy (RLT) is one of the most promising new treatments of metastatic castration refractory prostate cancer. We present images of Ga-PSMA PET/CT and parameters of response of a 75-year-old heavily pretreated metastatic castration refractory prostate cancer patient with extended bone metastases, showing an extraordinary biochemical response in PSA-levels concordant to SUV decline in bone metastases. Furthermore, this case shows that CT is of no use in assessing response in bone metastases of prostate cancer.

177 Lu-labeled PSMA-617 is a promising new therapeutic agent for radioligand therapy (RLT) of patients with metastatic castration-resistant prostate cancer (mCRPC). Initiated by the German Society of Nuclear Medicine, a retrospective multicenter data analysis was started in 2015 to evaluate efficacy and safety of 177 Lu-PSMA-617 in a large cohort of patients., Methods: One hundred forty-five patients (median age, 73 y; range, 43-88 y) with mCRPC were treated with 177 Lu-PSMA-617 in 12 therapy centers between February 2014 and July 2015 with 1-4 therapy cycles and an activity range of 2-8 GBq per cycle. Toxicity was categorized by the common toxicity criteria for adverse events (version 4.0) on the basis of serial blood tests and the attending physician's report. The primary endpoint for efficacy was biochemical response as defined by a prostate-specific antigen decline ≥ 50% from baseline to at least 2 wk after the start of RLT., Results: A total of 248 therapy cycles were performed in 145 patients. Data for biochemical response in 99 patients as well as data for physician-reported and laboratory-based toxicity in 145 and 121 patients, respectively, were available. The median follow-up was 16 wk (range, 2-30 wk). Nineteen patients died during the observation period. Grade 3-4 hematotoxicity occurred in 18 patients: 10%, 4%, and 3% of the patients experienced anemia, thrombocytopenia, and leukopenia, respectively. Xerostomia occurred in 8%. The overall biochemical response rate was 45% after all therapy cycles, whereas 40% of patients already responded after a single cycle. Elevated alkaline phosphatase and the presence of visceral metastases were negative predictors and the total number of therapy cycles positive predictors of biochemical response., Conclusion: The present retrospective multicenter study of 177 Lu-PSMA-617 RLT demonstrates favorable safety and high efficacy exceeding those of other third-line systemic therapies in mCRPC patients. Future phase II/III studies are warranted to elucidate the survival benefit of this new therapy in patients with mCRPC., (© 2017 by the Society of Nuclear Medicine and Molecular Imaging.)

Unlabelled: Radiolabeled prostate-specific membrane antigen (PSMA) ligands represent a true theranostic concept for diagnosis and therapy in patients with relapsed or metastatic prostate cancer. The aim of this study was to evaluate the response to and tolerability of a single dose of (177)Lu-PSMA-617 in a large cohort of patients with metastatic castration-resistant prostate cancer (mCRPC)., Methods: The data of 82 consecutive patients (median age, 73 y; range, 43-87 y) with mCRPC who received a single dose of (177)Lu-PSMA-617 (mean, 5.9 ± 0.5 GBq) were retrospectively analyzed. Data were collected at baseline and 8 wk after therapy. (68)Ga-PSMA-11 PET/CT was performed on all patients to verify sufficient PSMA expression. Bone, lymph node, liver, and lung metastases were present in 99%, 65%, 17%, and 11% of the patients, respectively. Tolerability and response were evaluated using hematologic parameters, renal scintigraphy, clinical data, and the prostate-specific antigen (PSA) level at baseline and 8 wk after therapy application., Results: Six patients died, and 2 patients dropped out because they were not willing to continue therapy and follow-up. The complete dataset of 74 patients was available for analysis. Forty-seven patients (64%) showed a PSA decline, including 23 (31%) with a decline by more than 50%. Thirty-five patients (47%) had stable disease: the change in their PSA level ranged from less than a 50% decline to less than a 25% rise. Seventeen patients (23%) had progressive disease: their PSA level rose by more than 25%. There were no significant changes in hemoglobin, white blood cells, creatinine, or tubular extraction rates indicative of toxicity. There was a significant but mild decrease in platelets, but the median value was still within the reference range., Conclusion: This retrospective multicenter analysis suggests that radioligand therapy with (177)Lu-PSMA-617 is safe and well tolerated and has a considerable effect on PSA level. Therefore, it offers an additional therapeutic option for patients with mCRPC. These data may justify further prospective randomized studies to evaluate and prove the clinical benefit in terms of survival and quality of life., (© 2016 by the Society of Nuclear Medicine and Molecular Imaging, Inc.)

Background: Despite progress in treatment of metastatic castration-resistant prostate cancer (mCRPC), new approaches are urgently needed. Recently theranostic concepts using radiolabeled ligands of the prostate-specific membrane antigen (PSMA) have been developed for diagnostics and therapy of patients with advanced mCRPC. The aim of this study was to evaluate tumor response, adverse effects, and survival in patients undergoing radioligand therapy with Lu-PSMA-617., Methods: Fifty therapies using Lu-PSMA-617 were performed in 28 consecutive patients with mCRPC and exhausted conventional therapeutic options (median age, 73.4 years; range, 45-87 years). Data were retrospectively analyzed with focus on response, safety, and survival. The median overall survival was compared with that of a recent historical patient cohort treated with best supportive care prior to availability of Lu-PSMA-617., Results: Any PSA decline occurred in 59% and 75% of patients after 1 and 2 therapies. Moreover, a PSA decline of 50% or greater occurred in 32% and 50%. Therapies were well tolerated. Hematologic and renal parameters changed insignificantly; permanent xerostomia or other safety-related toxicity did not occur. The estimated median survival was 29.4 weeks, significantly longer than survival in the historical best supportive care group (19.7 weeks [hazard ratio, 0.44; 95% confidence interval, 0.20-0.95]; P = 0.031)., Conclusions: Results from 50 therapies show that radioligand therapy with Lu-PSMA-617 is effective and well tolerated and seems to increase overall survival. A future randomized controlled prospective study will be necessary to confirm these results.

Radioligand therapy (RLT) using 177Lu labelled inhibitors of the prostate-specific membrane antigen (177Lu-PSMA) is performed in patients with metastatic castration-resistant prostate cancer (mCRPC) after exhaustion of other options. German University Clinics offer RLT since 2013 on a compassionate use basis. The present consensus document includes recommendations for RLT with 177Lu-PSMA-617. These consensus statements were developed by an expert panel formed by the German Society of Nuclear Medicine (DGN) in December 2015. Statements include recommendations for indication, baseline tests, therapy protocol, concomitant therapy, dosimetry, and follow-up. Consensus recommendations aim to inform the attending medical staff, standardize 177Lu-PSMA-617 RLT, and improve quality of individual patient care.