BACKGROUND: Metachronous metastatic prostate cancer (mmPCa) patients harbor different characteristics and outcomes, relative to DeNovo metastatic PCa patients. Onset of metastatic disease might be influenced by primary PCa characteristics such as Gleason score (GS) or cancer stage, as well as overall survival (OS) by timing of metastatic onset.
METHODS: We relied on an institutional tertiary-care database to identify mmPCa patients. Kaplan Meier and Cox Regression models tested for onset of metastases and OS, stratified according to GS, pathological stage and time to mmPCa.
RESULTS: Of 341 mmPCa patients, 8% harbored GS6 versus 41% versus 51% GS7 and GS8-10. Median time to onset of metastatic disease was 79 versus 54 versus 41 months for GS6 versus GS7 versus GS8-10 (P = .01). Moreover, median time to onset of metastases was 64 versus 44 months for pT1-2 versus pT3-4 mmPCa patients undergoing radical prostatectomy (P = .027). In multivariable Cox regression models, higher GS and pT-stage was associated with earlier onset of metastases. Additionally, significant OS differences could be observed for time interval of < 24 versus 24-60 versus 60-120 versus ≥ 120 months between primary PCa diagnosis and onset of mmPCa. Specifically, median OS was 56 versus 69 versus 97 months versus not reached (P < .01) for these categories. In multivariable Cox regression, shorter time to metastatic onset was associated with shorter OS.
CONCLUSIONS: Timing of mmPCa is strongly influenced by grading and pT-stage in real-life setting. OS benefits can be observed with longer time interval between primary PCa diagnosis and onset of mmPCa.

Antibody-drug conjugates (ADCs) represent a novel type of targeted cancer therapy combining the specificity of monoclonal antibodies with the cytotoxicity of conventional chemotherapy. Recently, ADCs have demonstrated practice-changing efficacy across diverse solid cancers. The anti-NECTIN-4 ADC enfortumab vedotin (EV) has just been approved for patients with urothelial cancer and is currently under investigation for patients with castration-resistant prostate cancer (CRPC e.g. Phase II ENCORE trial). Our objective was to evaluate the efficacy of EV in established prostate cancer (PCa) cell lines and to examine the membranous NECTIN-4 expression in primary tumours (PRIM) and distant metastases (MET). NECTIN-4 was heterogeneously expressed in the panel of PCa cell lines. EV led to growth inhibition in NECTIN-4 expressing PCa cells (22Rv1 and LNCaP), whereas the NECTIN-4-negative PC-3 cells were significantly less responsive to EV, emphasizing the dependence of EV response on its target expression. Immunohistochemical staining revealed moderate membranous NECTIN-4 expression only in a small subgroup of CRPC patients with lung and peritoneal MET [n = 3/22 with H-score ≥100, median H-score 140 (IQR 130-150)], while 100% of PRIM (n = 48/48) and 86.4% of common MET sites (n = 19/22), including lymph node, bone and liver MET, were NECTIN-4 negative. In summary, EV may be effective in NECTIN-4-positive PCa. However, our findings demonstrate that the tumoural NECTIN-4 expression is predominantly low in metastatic PCa, which suggests that EV may only be effective in a biomarker-stratified subgroup.

OBJECTIVE: Rechallenge of [177Lu]Lu-PSMA-617 radioligand therapy (RLT) was proposed for patients who initially responded to PSMA-RLT experiencing partial remission, but relapsed into progression after a certain period of remission. However, only limited data is available regarding this approach. In this study, we analyzed the efficacy and safety profile of one or more series of [177Lu]Lu-PSMA-617 RLT rechallenge in patients from a prospective registry (REALITY Study, NCT04833517) after they initially benefited from PSMA-RLT.
METHODS: Forty-seven patients with metastatic castration-resistant prostate cancer (mCRPC) who had biochemical response to initial [177Lu]Lu-PSMA-617 RLT followed by disease progression received at least one (up to three) series of [177Lu]Lu-PSMA-617 RLT rechallenge. Biochemical response rates based on prostate-specific antigen (PSA) serum value, PSA-based progression-free survival (PFS) and overall survival (OS) were calculated. Adverse events of the treatment were assessed according to \'common terminology criteria for adverse events\' (CTCAE).
RESULTS: After one series of RLT rechallenge, a PSA decline of at least 50% was achieved in 27/47 patients (57.4%). The median PFS of all patients was 8.7 mo and the median OS was 22.7 mo, each calculated from the administration of the first rechallenge series. Patients who responded (PSA decline > 50%) to the rechallenge showed a median OS of 27.3 mo. Regarding PFS, a significant correlation (r = 0.4128, p = 0.0323) was found for these patients comparing initial and rechallenge RLT. Ten patients received a second and 3 patients received a third rechallenge series with 8/10 and 3/3 patients responding to repeated RLT rechallenge. No severe deterioration of adverse events rated by CTCAE criteria was observed.
CONCLUSIONS: [177Lu]Lu-PSMA-617 RLT rechallenge is associated with significant PSA response and encouraging survival outcome as well as a very favourable safety profile and should therefore be considered as a straight-forward treatment option in mCRPC patients, who previously benefited from PSMA-RLT.

UNASSIGNED: 68Ga-PSMA-11 is recommended for the selection of patients for treatment in the package insert for 177Lu-PSMA-617. We aimed to compare imaging properties and post-treatment outcomes from radioligand therapy (RLT) of patients selected with 68Ga-PSMA-11 and 18F-DCFPyL.
UNASSIGNED: We retrospectively evaluated 80 patients undergoing PSMA RLT, who had pretreatment imaging using either 68Ga-PSMA-11 or 18F-DCFPyL. For both groups, we compared the biodistribution and lesion uptake and the PSA response to treatment.
UNASSIGNED: Both agents had comparable biodistribution. Patients initially imaged with 18F-DCFPyL had a higher PSA response (66% vs. 42%), and more patients had a PSA50 response (72% vs. 43%) compared to patients imaged with 68Ga-PSMA-11.
UNASSIGNED: 18F-DCFPyL and 68Ga-PSMA-11 had comparable biodistribution and lesion uptake. Patients imaged with 18F-DCFPyL demonstrated clinical benefit to PSMA RLT comparable to those imaged with 68Ga-PSMA-11, and either agent can be used for screening patients.

BACKGROUND: The first approvals of novel systemic therapies within recent years for metastatic hormone-sensitive (mHSPC) were mainly based on improved overall survival (OS) and time to castration resistance (ttCRPC) in mHSPC patients stratified according to CHAARTED low (LV) versus high volume (HV) and LATITUDE low (LR) versus high-risk (HR) disease.
METHODS: Relying on our institutional tertiary-care database we identified all mHSPC stratified according to CHAARTED LV versus HV, LATITUDE LR versus HR and the location of the metastatic spread (lymph nodes (M1a) versus bone (M1b) versus visceral/others (M1c) metastases. OS and ttCRPC analyses, as well as Cox regression models were performed according to different metastatic categories.
RESULTS: Of 451 mHSPC, 14% versus 27% versus 48% versus 12% were classified as M1a LV versus M1b LV versus M1b HV versus M1c HV with significant differences in median OS: 95 versus 64 versus 50 versus 46 months (p < 0.001). In multivariable Cox regression models HV M1b (Hazard Ratio: 2.4, p = 0.03) and HV M1c (Hazard Ratio: 3.3, p < 0.01) harbored significant worse than M1a LV mHSPC. After stratification according to LATITUDE criteria, also significant differences between M1a LR versus M1b LR versus M1b HR versus M1c HR mHSPC patients were observed (p < 0.01) with M1b HR (Hazard Ratio: 2.7, p = 0.03) and M1c HR (Hazard Ratio: 3.5, p < 0.01), as predictor for worse OS. In comparison between HV M1b and HV M1c, as well as HR M1b versus HR M1c no differences in ttCRPC or OS were observed.
CONCLUSIONS: Significant differences exist between different metastatic patterns of HV and LV and HR and LR criteria. Best prognosis is observed within M1a LV and LR mHSPC patients.

The 2024 ASCO Genitourinary Cancer Symposium, this year celebrating the 20th anniversary, delved into key advancements in urothelial carcinoma (UC) and prostate cancer (PC). For UC, insights emerged from adjuvant pembrolizumab for muscle-invasive urothelial carcinoma, and from the efficacy of the EV-302 study of enfortumab vedotin +pembrolizumab in the metastatic setting. In PC, adjuvant therapy with high-dose radiotherapy schedules plus long-t erm ADT was explored. In metastatic castration-resistant PC, highlights included a novel combo (cabozantinib+atezolizumab) for poor prognosis patients; confirmed benefits of ARSI+PARPi in BRCA-mutated patients; and safety considerations for ARSI treatments. The symposium continued its role as an indispensable platform for shaping specialized oncological care.

BACKGROUND: The landscape of systemic therapies for metastatic hormone-sensitive (mHSPC) and castration resistant prostate cancer (mCRPC) extensively improved within the last decades resulting in a significantly prolonged overall survival. However, subgroup analyses of phase III trials suggest potentially different overall survival outcomes for older adults.
METHODS: We relied on our institutional metastatic prostate cancer database to identify mHSPC and subsequently mCRPC patients. Older adults were stratified according to age groups 70-74 versus ≥75-79 versus ≥80 years at metastatic occurrence. Subsequently, uni- and multivariable time to mCRPC and overall survival analyses were performed.
RESULTS: Of 494 older adults, 217 (44%) were 70-74 versus 180 (36%) 75-79 versus 97 (20%) ≥80 years old. Rates of local prostate cancer treatment differed significantly between all three groups (p < 0.01). Regarding mHSPC treatment, androgen receptor signaling inhibitors (ARSI) were administered in 30-39% of patients and docetaxel with 9% in age group 70-74 years and 6% and 3% in age groups 75-79 years and ≥80 years. Regarding mCRPC treatment, significant differences between treatment proportions were observed (p < 0.01). Most common treatment was ARSI for all three groups. Conversely, chemotherapy was more frequently administered in patients aged 70-74 (16%), relative to 4% and 3% in 75-79 year and ≥80 year aged patients. In univariable and multivariable time to mCRPC analyses, overall survival in mHSPC and OS in mCRPC analyses, no significant differences between all three age groups were observed (all p ≥ 0.3).
CONCLUSIONS: Treatment patterns differ significantly between older adults with metastatic prostate cancer. However, these differences may not result in differences of overall life expectancy.

The objective of this retrospective study is to assess the effectiveness and safety of two beta-emitting prostate-specific membrane antigen (PSMA) radioligands, [177Lu]Lu and [161Tb]Tb, in heavily treated patients with metastatic castration-resistant prostate cancer (mCRPC). A total of 148 cycles of beta-emitting PSMA radioligand therapy were given to 53 patients at a specialized cancer care center in Amman, Jordan. This treatment was offered following the exhaustion of all prior treatment modalities. Approximately half of the cases (n = 26) demonstrated an initial partial response to PSMA radioligand therapy. Moreover, roughly one-fourth of the patients (n = 13) exhibited a sustained satisfactory biochemical response, which qualified them to receive a total of six PSMA radioligand therapy cycles and maintain continued follow-up for additional treatment cycles. This was reflected by an adequate prostate-specific antigen (PSA) decline and a concomitant partial response evident on [68Ga]Ga-PSMA positron emission tomography/computed tomography imaging. A minority of patients (n= 18; 34%) experienced side effects. Generally, these were low-grade and self-limiting toxicities. This study endorses previous research evidence about PSMA radioligand therapy\'s safety and efficacy. It also provides the first clinical insight from patients of Arab ethnicity. This should facilitate and promote further evidence, both regionally and internationally.

The aim of this work is to evaluate our clinical real-world data obtained with 225Ac-PSMA-617 (AcPSMA), which were acquired under compassionate care regulations in patients with advanced-stage prostate cancer. The objective parameters that could be derived from this evaluation are compared with previous literature about AcPSMA and 177Lu-PSMA-617 (LuPSMA). Methods: The medical files of all patients who had received AcPSMA on an individual patient basis at the Heidelberg University Hospital since January 2014 were analyzed retrospectively. Previously published patients were excluded. The remaining patients were tailored into 2 subgroups with different treatment strategies: group 1 received AcPSMA as a deescalated monotherapy, and group 2 received LuPSMA plus AcPSMA as a cocktail regimen. Baseline characteristics, serum prostate-specific antigen (PSA) response, and overall survival were compared with the most appropriate historical controls. Results: Of 287 patients treated, 54 were excluded because of previous publication and 233 were evaluated, 104 of whom received AcPSMA monotherapy (median, 6 MBq). In this group, 55 patients (53%) presented with a best PSA response of at least 50%. The other 129 patients received a cocktail therapy of AcPSMA (median, 4 MBq) plus LuPSMA (4 GBq). In this group, a best PSA response of at least 50% was observed in 74 patients (57%). The median overall survival in the monogroup was 9 mo and in the cocktail group was 15 mo. If adjusted for prognostic baseline characteristics, the efficacy of both regimens was not significantly different. Conclusion: Deescalated treatment activities of AcPSMA or AcPSMA and LuPSMA cocktail regimens present better tolerability with regard to xerostomia than previous regimens of at least 100 kBq/kg while retaining high antitumor activity in poor-prognosis prostate cancer patients.

Despite the inclusion of multiple agents within the prostate cancer treatment landscape, new treatment options are needed to address the unmet need for patients with metastatic castration-resistant prostate cancer (mCRPC). Although prostate-specific membrane antigen is the only cell-surface target to yield clinical benefit in men with advanced prostate cancer, additional targets may further advance targeted immune, cytotoxic, radiopharmaceutical, and other tumor-directed therapies for these patients. Human kallikrein 2 (hK2) is a novel prostate-specific target with little to no expression in nonprostate tissues. This first-in-human phase 0 trial uses an 111In-radiolabeled anti-hK2 monoclonal antibody, [111In]-DOTA-h11B6, to credential hK2 as a potential target for prostate cancer treatment. Methods: Participants with progressive mCRPC received a single infusion of 2 mg of [111In]-DOTA-h11B6 (185 MBq of 111In), with or without 8 mg of unlabeled h11B6 to assess antibody mass effects. Sequential imaging and serial blood samples were collected to determine [111In]-DOTA-h11B6 biodistribution, dosimetry, serum radioactivity, and pharmacokinetics. Safety was assessed within a 2-wk follow-up period from the time of [111In]-DOTA-h11B6 administration. Results: Twenty-two participants received [111In]-DOTA-h11B6 and are included in this analysis. Within 6-8 d of administration, [111In]-DOTA-h11B6 visibly accumulated in known mCRPC lesions, with limited uptake in other organs. Two treatment-emergent adverse events unrelated to treatment occurred, including tumor-related bleeding in 1 patient, which led to early study discontinuation. Serum clearance, biodistribution, and tumor targeting were independent of total antibody mass (2 or 10 mg). Conclusion: This first-in-human study demonstrates that tumor-associated hK2 can be identified and targeted using h11B6 as a platform as the h11B6 antibody selectively accumulated in mCRPC metastases with mass-independent clearance kinetics. These data support the feasibility of hK2 as a target for imaging and hK2-directed agents as potential therapies in patients with mCRPC.