Talazoparib Plus Enzalutamide in Patients With HRR-Deficient mCRPC: Practical Implementation Steps for Oncology Nurses and Advanced Practice Providers.

BACKGROUND: About one-quarter of patients with advanced prostate cancer have alterations in homologous recombination repair (HRR) genes. In a global phase 3 study, talazoparib plus enzalutamide significantly improved progression-free survival in patients with HRR-deficient metastatic castration-resistant prostate cancer (mCRPC). OBJECTIVES: This article reviews the role of oncology nurses and advanced practice providers (APPs) in administering talazoparib plus enzalutamide in patients with mCRPC. METHODS: This review and hypothetical case study illustrate the role of oncology nurses and APPs in the administration of talazoparib plus enzalutamide and the management of adverse events to ensure safe and effective use in clinical practice. FINDINGS: Oncology nurses and APPs play an important role in the dosing and administration of talazoparib plus enzalutamide and can recognize and manage adverse events in patients with HRR-deficient mCRPC.

Efficacy and Toxicity of [177Lu]Lu-PSMA-617 for Metastatic Castration-Resistant Prostate Cancer: Results from the U.S. Expanded-Access Program and Comparisons with Phase 3 VISION Data.

The phase 3 VISION trial demonstrated that [177Lu]Lu-PSMA-617 prolonged progression-free survival and overall survival (OS) in prostate-specific membrane antigen [PSMA]-positive metastatic castration-resistant prostate cancer (mCRPC) patients who progressed on taxane-based chemotherapy and androgen receptor-signaling inhibitors (ARSIs). The U.S. expanded-access program (EAP; NCT04825652) was opened to provide access to [177Lu]Lu-PSMA-617 for eligible patients until regulatory approval was obtained. This study aimed to evaluate the efficacy and safety profile of [177Lu]Lu-PSMA-617 within the EAP and compare the results with those from the VISION trial. Methods: Patients enrolled in the EAP at 4 institutions in the United States with available toxicity and outcome data were included. Outcome measures included OS, a prostate-specific antigen (PSA) response rate (RR) of at least 50%, and incidences of toxicity according to Common Terminology Criteria for Adverse Events version 5.0. Differences in baseline characteristics, outcome data, and toxicity between the EAP and VISION were evaluated using t testing of proportions and survival analyses. Results: In total, 117 patients with mCRPC who received [177Lu]Lu-PSMA-617 within the EAP between May 2021 and March 2022 were eligible and included in this analysis. Patients enrolled in the EAP were more heavily pretreated with ARSI (≥2 ARSI regimens: 70% vs. 46%; P < 0.001) and had worse performance status at baseline (Eastern Cooperative Oncology Group score ≥ 2: 19% vs. 7%; P < 0.001) than VISION patients. EAP and VISION patients had similar levels of grade 3 or higher anemia (18% vs. 13%; P = 0.15), thrombocytopenia (13% vs. 8%; P = 0.13), and neutropenia (3% vs. 3%; P = 0.85) and similar PSA RRs (42% vs. 46%; P = 0.50) and OS (median: 15.1 vs. 15.3 mo; P > 0.05). Conclusion: Patients with PSMA-positive mCRPC who received [177Lu]Lu-PSMA-617 within the EAP were later in their disease trajectory than VISION patients. Patients enrolled in the EAP achieved similar PSA RRs and OS and had a safety profile similar to that of the VISION trial patients.

Durable benefit from poly(ADP-ribose) polymerase inhibitors in metastatic prostate cancer in routine practice: biomarker associations and implications for optimal clinical next-generation sequencing testing.

BACKGROUND: Controlled trials have consistently demonstrated the efficacy of poly(ADP-ribose) polymerase inhibitors (PARPis) in patients with metastatic castration-resistant prostate cancer (mCRPC) and BRCA1 or BRCA2 alterations (BRCAalt). However, the reported efficacy of PARPi for alterations in other homologous recombination repair (HRR) genes is less consistent. We sought to evaluate the routine practice effectiveness of PARPi between and within these groups. DESIGN: Patient-level data from a deidentified nationwide (USA-based) cancer clinico-genomic database between January 2011 and September 2023 were extracted. Patients with mCRPC and comprehensive genomic profiling by liquid biopsy [circulating tumor DNA (ctDNA)] or tissue (tumor) biopsy and who received single-agent PARPi were included and grouped by BRCAalt, ATMalt, other HRR, or no HRR. We further subcategorized BRCAalt into homozygous loss (BRCAloss) and all other deleterious BRCAalt (otherBRCAalt). RESULTS: A total of 445 patients met inclusion criteria: 214 with tumor and 231 with ctDNA. BRCAalt had more favorable outcomes to PARPi compared with ATM, other HRR, and no HRR groups. Within the BRCAalt subgroup, compared with other BRCAalt, BRCAloss had a more favorable time to next treatment (median 9 versus 19.4 months, P = 0.005), time to treatment discontinuation (median 8 versus 14 months, P = 0.006), and routine practice overall survival (median 14.7 versus 19.4 months, P = 0.016). Tumor BRCAloss prevalence (3.1%) was similar to ctDNA prevalence in liquid biopsy specimens with high tumor fraction (>20%). BRCAloss was not detected in orthogonal germline testing. CONCLUSIONS: PARPi routine practice effectiveness between groups mirrors prospective trials. Within the BRCAalt group, BRCAloss had the best outcomes. Unless the ctDNA tumor fraction is very high, somatic tissue testing (archival or metastatic) should be prioritized to identify patients who may benefit most from PARPi. When tissue testing is not clinically feasible, sufficient ctDNA tumor fraction levels for detection are enriched at clinical timepoints associated with tumor progression.

Early treatment response assessment with [177Lu]PSMA whole-body-scintigraphy compared to interim PSMA-PET.

BACKGROUND: Prostate-specific membrane antigen positron emission tomography (PSMA-PET) is an essential tool for patient selection before radioligand therapy (RLT). Interim-staging with PSMA-PET during RLT allows for therapy monitoring. However, its added value over post-treatment imaging is poorly elucidated. The aim of this study was to compare early treatment response assessed by post-therapeutic whole-body scans (WBS) with interim-staging by PSMA-PET after 2 cycles in order to prognosticate OS. METHODS: Men with metastasized castration-resistant PC (mCRPC) who had received at least two cycles of RLT, and interim PSMA-PET were evaluated retrospectively. PROMISE V2 framework was used to categorize PSMA expression and assess response to treatment. Response was defined as either disease control rate (DCR) for responders or progression for non-responders. RESULTS: A total of 188 men with mCRPC who underwent RLT between February 2015 and December 2021 were included. The comparison of different imaging modalities revealed a strong and significant correlation with Cramer V test: e.g. response on WBS during second cycle compared to interim PET after two cycles of RLT (cφ = 0.888, P < 0.001, n = 188). The median follow-up time was 14.7 months (range: 3-63 months; 125 deaths occurred). Median overall survival (OS) time was 14.5 months (95% CI: 11.9-15.9). In terms of OS analysis, early progression during therapy revealed a significantly higher likelihood of death: e.g. second cycle WBS (15 vs. 25 months, P < 0.001) with a HR of 2.81 (P < 0.001) or at PET timepoint after 2 cycles of RLT (11 vs. 24 months, P < 0.001) with a HR of 3.5 (P < 0.001). For early biochemical response, a PSA decline of at least 50% after two cycles of RLT indicates a significantly lower likelihood of death (26 vs. 17 months, P < 0.001) with a HR of 0.5 (P < 0.001). CONCLUSION: Response assessment of RLT by WBS and interim PET after two cycles of RLT have high congruence and can identify patients at risk of poor outcome. This indicates that interim PET might be omitted for response assessment, but future trials corroborating these findings are warranted.

Safety and clinical activity of BMS-986365 (CC-94676), a dual androgen receptor ligand-directed degrader and antagonist, in heavily pretreated patients with metastatic castration-resistant prostate cancer.

BACKGROUND: Metastatic castration-resistant prostate cancer (mCRPC) that progresses on androgen receptor pathway inhibitors (ARPIs) may continue to be driven by AR signaling. BMS-986365 is an orally administered ligand-directed degrader targeting the AR via a first-in-class dual mechanism of AR degradation and antagonism. CC-94676-PCA-001 (NCT04428788) is a phase 1 multicenter study of BMS-986365 in patients with progressive mCRPC. PATIENTS AND METHODS: Patients who progressed on androgen deprivation therapy, ≥ 1 ARPI, and taxane chemotherapy (unless declined/ineligible) were enrolled. The study included dose escalation (Part A) and expansion (Part B) of BMS-986365 up to 900 mg twice daily (BID). Primary objectives were safety, tolerability, and to define maximum tolerated dose (MTD) and/or recommended phase 2 dose (RP2D). Key secondary endpoints included decline in prostate-specific antigen ≥50% (PSA50) and radiographic progression-free survival (rPFS). RESULTS: Parts A and B enrolled 27 and 68 patients, respectively. In Part B, the median number of prior therapies was 4 (range 2-11). The most common treatment-related adverse events (TRAEs) were asymptomatic prolonged corrected QT interval (47%) and bradycardia (34%). Part A MTD was not reached and RP2D selection is ongoing. Across Part B three highest doses (400-900 mg BID, n = 60), PSA50 was 32% (n = 19), including 50% (n = 10/20) at 900 mg; median rPFS (95% CI) was 6.3 months (5.3-12.6), including 8.3 months (3.8-16.6) at 900 mg; and rPFS was longer in patients without versus with prior chemotherapy: 16.5 months (5.5-not evaluable) versus 5.5 months (2.7-8.3), respectively. Efficacy was observed in patients with AR ligand binding domain (LBD) WT or with AR LBD mutations. CONCLUSIONS: BMS-986365 was well tolerated, with a manageable safety profile, and demonstrated activity in heavily pretreated patients with potentially higher benefit in chemotherapy-naïve patients. These data show BMS-986365's potential to overcome resistance to current ARPIs, regardless of AR LBD mutation status.

Efficacy and safety of rechallenge with [177Lu]Lu-PSMA-I&T radioligand therapy in metastatic castration resistant prostate cancer.

BACKGROUND: The purpose of this study was to evaluate the safety and outcome of rechallenge [177Lu]Lu-PSMA-I&T in newly progressed mCRPC patients after response to initial [177Lu]Lu-PSMA radioligand therapy (PRLT). METHODS: We retrospectively included 18 patients who underwent rechallenge with [177Lu]Lu-PSMA-I&T. All patients presented with (i) newly progressed disease after response to initial PRLT; (ii) a [68Ga]Ga-PSMA-11 PET/CT confirming the presence of PSMA-positive metastases; iii) ECOG performance status 0-1. Adverse events were graded according to CTCAE v5.0. Response was assessed by PSA and classified according to PCWG3 recommendations. For patients who underwent restaging with [68Ga]Ga-PSMA-11 PET/CT, imaging response was categorised according to adapted PERCIST v1.0. In patients with discordant [68Ga]Ga-PSMA-11 PET/CT and PSA, other available imaging modalities were evaluated to confirm disease status. Overall survival (OS) was calculated from the first cycle of initial PRLT and rechallenge PRLT, respectively, until last patient contact or death. RESULTS: Patients were initially treated with a median of 5 cycles (range 4-7) and were rechallenged after a median of 9 months (range 3-13). Each patient received a median of 4 (range 2-7) rechallenge cycles (median cumulative activity 26.1 GBq). None of the patients experienced life-threatening G4 adverse events during either treatment period. Grade 3 adverse events included one case of anaemia, one case of thrombocytopenia, and one case of renal failure. In 8/18 patients long-term toxicities were evaluated. Serious toxicities (≥ Grade 3) occurred in 3/8 patients (n = 1 G4 thrombocytopenia, n = 1 G4 renal failure and n = 1 pancytopenia and G4 renal failure). Best PSA50%-response was observed in 44% of patients and PSA-disease control was confirmed in 56% of patients at the last cycle. Of the 12/18 patients restaged by imaging, 6/12 (50%) patients had disease control (partial response/stable disease), 1/12 had a mixed response, and 5/12 had progression. After a median follow-up time of 25 months (range 14-44), 10 patients had died, 7 were still alive, and one patient was lost at follow-up. The median OS was 29 months (95%CI, 14.3-43.7 months) for the initial treatment and 11 months (95%CI, 8.1-13.8 months) for the first rechallenge course. CONCLUSION: More than half of patients benefit from rechallenge PRLT. Our analysis suggests that rechallenge may prolong survival in selected patients, with an acceptable safety profile.

Phase II trial of multi-kinase inhibitor ESK981 in patients with metastatic castration-resistant prostate cancer.

ESK981 is a potent tyrosine kinase and PIKfyve lipid kinase inhibitor. This phase II trial evaluated the efficacy of ESK981 as a single agent in patients with androgen receptor-positive (AR +) metastatic castration-resistant prostate cancer (mCRPC). Eligible patients had mCRPC with progression on AR-targeted agents and without prior chemotherapy treatment. Each patient received 160 mg ESK981 once daily for 5 days per week for 4 weeks per cycle (except for an adverse event (AE) occurrence). The primary endpoints were a 50% reduction in prostate-specific antigen (PSA50), and safety. Secondary endpoints included the time and the duration of PSA response, PSA progression rates, PSA progression free survival (PFS) and overall survival (OS). Exploratory investigations included whole exome sequencing in patients before treatment, and morphological evaluation of biopsy samples pre- and post-treatment. PSA was evaluated in 13 patients. Only one patient (7.7% two-sided 95% Wilson CI (0.4%, 33.3%)) experienced a reduction in their PSA levels by 50% or more. The most common grade 3 treatment-related AEs were cardiac disorders, diarrhea, hypertension, alanine transaminase and aspartate transaminase elevations. No grade 4-5 events occurred. Median PFS was 1.8 months, and median OS was 12.1 months. Peripheral immune cells showed increased T cell activation and cytokine production in two patients who received 12-weeks of ESK981. Although relatively well tolerated, ESK981 alone showed no anti-tumor activity in patients with AR + mCRPC and its further evaluation as a single agent in AR + mCRPC is not warranted. (Trial registration: ClinicalTrials.gov, NCT03456804. Registration date: March 7, 2018).

Personalized dosimetry assessment of [177Lu]Lu-PSMA-617 radioligand therapy in the management of metastatic castration-resistant prostate cancer.

INTRODUCTION: Prostate-specific membrane antigen (PSMA)-targeted radioligand therapy (RLT) is revolutionizing the treatment landscape for metastatic castration-resistant prostate cancer (mCRPC) patients. This study aimed to establish patient-specific radiation dosimetry for [177Lu]Lu-PSMA-617 RLT in Iranian patients with mCRPC. METHOD: Twelve biopsy-proven prostate cancer patients (aged 68.73 ± 5.26 yr) underwent 6.62 ± 0.36 GBq [177Lu]Lu-PSMA-617 RLT. Post-therapy whole-body planar scans were acquired approximately at 4, 48, and 72 h post-administration, alongside a single SPECT/CT around 48 h using Siemens Symbia T2 to obtain cumulated activity. An imaging protocol and dosimetry approach were designed to balance between time efficacy and accuracy in post-therapeutic dosimetry. Using accurate activity calibration, S-values were calculated by importing SPECT/CT images as the source/geometry into the Geant4 application for the tomographic emission (GATE) Monte Carlo (MC) toolkit. The Medical Internal Radiation Dose (MIRD) scheme was followed for subsequent absorbed dose (AD) calculations in organs at risk (OAR) and tumoral lesions using the dose actor and accumulated activities for precise dose estimations. RESULTS: Using the MC approach, the mean ADs to the liver, spleen, right and left kidneys, and tumor lesions were 0.11 ± 0.04 Gy/GBq, 0.08 ± 0.03 Gy/GBq, 0.34 ± 0.09 Gy/GBq, 0.34 ± 0.10 Gy/GBq, and 0.83 ± 0.54 Gy/GBq, respectively. Notably, tumoral lesions demonstrated significantly higher ADs, indicating enhanced uptake of radiopharmaceuticals by malignant cells. CONCLUSIONS: This study indicates that the ADs of OARs and tumoral lesions from [177Lu]Lu-PSMA-617 RLT in patients with mCRPC are consistent with existing literature. The dosimetry findings suggest that increasing the administered activity of [177Lu]Lu-PSMA-617 RLT is feasible and does not pose a significant risk of adverse effects on OARs, as supported by our data. However, to validate the safety and efficacy of higher doses, further clinical follow-up studies are recommended.

Outcomes of First Subsequent Taxane Therapy in Patients with Metastatic Castration-Resistant Prostate Cancer Who Previously Received Docetaxel Intensification for Metastatic Castration-Sensitive Prostate Cancer.

BACKGROUND: The management of advanced prostate cancer continues to evolve rapidly, particularly with the earlier use of survival-prolonging therapies in metastatic castration-sensitive prostate cancer (mCSPC). Though approved prior to the use of intensification therapy in mCSPC, taxane-based chemotherapies remain a relevant option for patients with metastatic castration-resistant prostate cancer (mCRPC). However, there is little evidence determining the outcomes of taxane chemotherapies as the first subsequent taxane (FST) in mCRPC pts who received docetaxel intensification (DI) in mCSPC. The purpose of this study is to compare outcomes between the survival-prolonging taxanes, docetaxel and cabazitaxel as FST after DI. METHODS: New patient consults seen at the Cross Cancer Institute from 1 July 2014 to 31 December 2020 were retrospectively reviewed. Pts were considered eligible if they received DI for mCSPC and then received either docetaxel or cabazitaxel in mCRPC. Variables of interest were collected from electronic medical records. The primary endpoint was ≥50% PSA response at 12 weeks relative to baseline for FST. Secondary endpoints included OS from mCSPC diagnosis, as well as PFS and OS from the FST start date. PSA responses were compared using the chi-squared test, and time-based endpoints were compared using the Kaplan-Meier method. RESULTS: In total, 34 pts were identified: docetaxel = 22 and cabazitaxel = 12 as FST. 91.2% of pts (docetaxel 95.5% vs. cabazitaxel 83.3%) received FST in 2nd line mCRPC. The median age at diagnosis (63.1 vs. 67.1 yrs, p = 0.236) and the median time to CRPC (18.6 vs. 14.2 mos, p = 0.079) were similar for docetaxel and cabazitaxel, respectively. The median time to FST (24.1 vs. 34.6 mos, p = 0.036) and OS from mCSPC diagnosis (30.9 vs. 52.7 mos, p = 0.002) were significantly shorter for pts receiving cabazitaxel vs. docetaxel. PSA responses occurred in 40.9% of pts treated with docetaxel compared to 25.0% treated with cabazitaxel (p = 0.645). There was no significant difference in median PFS (2.7 vs. 3.5 mos, p = 0.727) or median OS (11.4 vs. 8.1 mos, p = 0.132) from the time of FST for pts treated with docetaxel vs. cabazitaxel, respectively. CONCLUSIONS: Both docetaxel and cabazitaxel demonstrated activity as FST after DI in mCSPC. Pts who received cabazitaxel had a shorter time to FST and OS from mCSPC. The reasons for this may reflect clinician preference for cabazitaxel in pts with aggressive or rapidly progressing disease. No difference was found in PSA response, PFS, or OS from FST with docetaxel compared to cabazitaxel. While limited by its retrospective nature and small sample size, this study suggests that docetaxel is active as FST despite treatment with DI in mCSPC.

Low-dose abiraterone plus Olaparib as a late-line treatment for mCRPC patients without BRCA1/2 mutations: a multicenter retrospective pilot study.

Although overall survival data are still premature, the PROpel study found radiological progression-free survival (PFS) benefits of abiraterone and olaparib in patients with metastatic castration-resistant prostate cancer (mCRPC). However, for patients who have not been genetically tested or lack BRCA1/2 mutations (BRCAm), this combination therapy has been questioned as a first-line conventional treatment for mCRPC, mainly due to significant health economics and side effects. In our retrospective study, we found that treatment with low-dose abiraterone plus olaparib as a late-line treatment for mCRPC could lead to prostate-specific antigen (PSA) and symptom PFS in selective cases even without BRCAm. The median PSA-PFS was 8 months (IQR: 6.5-11.5), with a median follow-up duration of 39.0 months (IQR: 27.5-64.5). Gene tests were conducted in all patients, identifying non-BRCA mutations through ctDNA testing (24%), tumor tissue testing (12%), or both (64%). Adverse events occurred in 72% of patients, with 16% experiencing Grade ≥ 3 events. Common adverse events included anemia (64%), decreased appetite (48%), and fatigue (25%). Our findings support low-dose abiraterone plus olaparib as a potential option for mCRPC patients without BRCAm, offering manageable safety and efficacy profiles.

Design of 225Ac-PSMA for targeted alpha therapy in prostate cancer.

The first alpha emitting radiopharmaceutical, 223RaCl2, radium dichloride, was approved 10 years ago into the clinical armament of treating bone metastases in metastatic castration-resistant prostate cancer (mCRPC). In addition to this, the first beta-emitting radionuclide Lu-177 chelated with a prostate-specific membrane antigen (PSMA) compound, got last year its marketing approval for the third line treatment of mCRPC. Therefore, there is great excitement about combining alpha-emitters and prostate cancer targeting PSMA compounds. This review describes the clinical history of alpha-emitting PSMA in treating mCRPC. Here, we present the potential, current status, and opportunities for 225Ac-PSMA therapy. The work reviews the basic concepts, current treatment outcome, and toxicity, and areas requiring further investigations such as dosimetric aspects in clinical studies covering more than 400 patients. In general, approximately two-thirds of the patients benefit from this third-line therapy. There is also successful evidence of using 225Ac-PSMA in the second-line of prostate cancer management. The future potential of 225Ac-PSMA therapy and targeted alpha therapy (TAT) of cancer in general is enormous. According to our overview the clinical experience with 225Ac-PSMA therapy to date has shown great benefit and physicians dedicated to theragnostics are anxiously waiting for new applications. Hopefully, this review helps in deeper understanding of the strengths and limitations of TAT and may help in creating effective therapy protocols.

Analysis of Molecular Imaging and Laboratory Baseline Biomarkers in PSMA-RLT: Whole-Body Total Lesion PSMA (TLP) Predicts Overall Survival.

The aim of this retrospective study was to identify pre-therapeutic predictive laboratory and molecular imaging biomarkers for response and overall survival (OS) in patients with metastatic castration-resistant prostate cancer (mCRPC) treated with prostate-specific membrane antigen (PSMA)-targeted radioligand therapy (RLT). Pre-therapeutic laboratory and [68Ga]Ga-PSMA-11 PET/CT data of n = 102 mCRPC patients receiving [177Lu]Lu-PSMA-617 RLT within a prospective registry (REALITY Study, NCT04833517) were analyzed including laboratory parameters such as alkaline phosphatase (ALP), prostate-specific antigen (PSA), gamma glutamyl transferase (GGT), glutamate oxaloacetate transaminase (GOT), glutamate pyruvate transaminase (GPT), neuron specific enolase (NSE), hemoglobin (Hb), and imaging parameters such as maximum standardized uptake value of the tumor lesions (SUVmax), the mean standardized uptake value of all tumor lesions (SUVmean), the whole-body molecular tumor volume (MTV), and the whole-body total lesion PSMA (TLP). Mann-Whitney U test, univariate and multivariable Cox-regression were performed to test for association of the parameters with response and OS. The SUVmean of all lesions was significantly different between responders and non-responders (SUVmean responders 8.95 ± 2.83 vs. non-responders 7.88 ± 4.46, p = 0.003), whereas all other tested biochemical and imaging parameters did not reveal significant differences. Hb and the molecular imaging parameters MTV and TLP showed a significant association with OS (p = 0.013, p = 0.005; p = 0.009) in univariant Cox regression; however, only TLP remained significant in multivariable analysis (Hazard ratio 1.033, p = 0.009). This study demonstrates a statistically significant association between the quantitative PET/CT imaging parameter SUVmean and PSA response, as well as between the baseline TLP and OS of mCRPC patients undergoing RLT.

Detection of tumour heterogeneity in patients with advanced, metastatic castration-resistant prostate cancer on [68Ga]Ga-/[18F]F-PSMA-11/-1007, [68Ga]Ga-FAPI-46 and 2-[18F]FDG PET/CT: a pilot study.

PURPOSE: In metastatic castration-resistant prostate cancer (mCRPC), some patients show low/absent PSMA expression in tumour lesions on positron emission tomography (PET) scans, indicating heterogeneity and heightened risk of non-response to PSMA-RLT (radioligand therapy). Imaging cancer-associated fibroblasts and glucose uptake may further characterise tumour heterogeneity in mCRPC patients. Here, we aimed to evaluate tumour heterogeneity and its potential implications for management in mCRPC patients assessed for PSMA-RLT using [68Ga]Ga-FAPI-46, 2-[18F]FDG and [68Ga]Ga-/[18F]F-PSMA-11/-1007 PET. MATERIAL AND METHODS: Patients with advanced, progressive mCRPC underwent clinical [68Ga]Ga-/[18F]F-PSMA-11/-1007, 2-[18F]FDG and [68Ga]Ga-FAPI-46 PET/CT to evaluate treatment with PSMA-directed RLT. Tumour detection/semiquantitative parameters were compared on a per-lesion/-region basis. Two phenotypes were defined: Criteria for the mixed phenotype were: (a) PSMA-negative findings for lymph node metastases ≥ 2.5 cm, any solid organ metastases ≥ 1.0 cm, or bone metastases with soft tissue component ≥ 1.0 cm, (b) low [68Ga]Ga-/[18F]F-PSMA-11/-1007 uptake and/or (c) balanced tumour uptake of all radioligands. The PSMA-dominant phenotype was assigned if the criteria were not met. RESULTS: In ten patients, 472 lesions were detected on all imaging modalities (miTNM regions: M1b: 327 (69.3%), M1a: 95 (20.1%), N1: 26 (5.5%), M1c: 18 (3.8%), T: 5 (1.1%) and Tr: 1 (0.2%). [68Ga]Ga-/[18F]F-PSMA-11/-1007 (n = 453 (96.0%)) demonstrates the highest detection rate, followed by [68Ga]Ga-FAPI-46 (n = 268 (56.8%))/2-[18F]FDG (n = 241 (51.1%)). Semiquantitative uptake was highest for [68Ga]Ga-/[18F]F-PSMA-11/-1007 (mean SUVmax (interquartile range): 22.7 (22.5), vs. [68Ga]Ga-FAPI-46 (7.7 (3.7)) and 2-[18F]FDG (6.8 (4.7)). Seven/three patients were retrospectively assigned to the PSMA-dominant/mixed phenotype. Median overall survival was significantly longer for patients who underwent [177Lu]Lu-PSMA-617 RLT and were retrospectively assigned to the PSMA-dominant phenotype (19.7 vs. 9.3 months). CONCLUSION: Through whole-body imaging, we identify considerable inter- and intra-patient heterogeneity of mCRPC and potential imaging phenotypes. Regarding uptake and tumour detection, [68Ga]Ga-/[18F]F-PSMA-11/-1007 was superior to [68Ga]Ga-FAPI-46 and 2-[18F]FDG, while the latter two were comparable. Patients who underwent [177Lu]Lu-PSMA-617 RLT based on clinical-decision making had a longer overall survival and could be assigned to the PSMA-dominant phenotype.

Real-World Treatment Patterns in Patients With Metastatic Castration-Resistant Prostate Cancer in Greece: The PROSPECT Study.

INTRODUCTION: Real-world data on management of metastatic castration resistant prostate cancer (mCRPC) with novel therapies is sparse. The aim of this study was to capture real-world management strategies in patients with mCRPC who initiated first line (1L) systemic therapy with chemotherapy or novel hormonal agents (NHAs) in Greece and describe the therapeutic sequencing strategy among patients who advanced to 2L and 3L treatment. PATIENTS AND METHODS: In this noninterventional, multicentre, retrospective study (PROSPECT), a medical chart review of 149 patients with mCRPC who initiated 1L systemic therapy with chemotherapy or NHAs in 7 major anticancer hospital clinics, from public, academic, and private sectors in Greece was conducted. All endpoints were descriptively analysed. Kaplan-Meier was used for time-to-event outcomes. RESULTS: At 1L (N = 149), most (78.5%) patients received NHAs; enzalutamide (52.3%), and abiraterone (26.2%). At 2L (N = 68), most (72.1%) patients received chemotherapy, most frequently docetaxel (50.0% of all patients). At 3L (N = 32), 56.3% and 31.3% of patients received chemotherapy and NHAs, respectively. Regarding treatment sequencing from 1L→2L (N = 68), most patients (55.9%) advanced from NHA→chemotherapy. Regarding treatment sequencing from 1L→2L→3L (N = 32), 34.4% advanced from NHAs→chemotherapy→chemotherapy and 31.3% from NHAs→chemotherapy→NHA. Estimated median times spent on treatment at 1L, 2L, and 3L were 9.8, 4.4, and 3.7 months, respectively. CONCLUSION: Most patients were treated with 1L NHAs, in accordance to established guidelines (which suggest both NHA and chemo as preferred 1st line options). There appeared to be a longer time on treatment of NHAs at 1L than chemotherapy, suggesting an unmet need for treatment optimisation/recommendations for 2L and 3L treatment in mCRPC.

Impact of time to metastatic disease onset and extent of disease volume across metastatic hormone-sensitive and castration-resistant prostate cancer.

OBJECTIVE: In recently published phase III trials, overall survival (OS) differences were demonstrated in patients with secondary vs. De Novo and low vs. high volume metastatic hormone-sensitive prostate cancer (mHSPC). We hypothesized that these factors may also be attributable in real-world setting of new intensified combination therapies and in metastatic castration resistant prostate cancer (mCRPC) patients. MATERIALS AND METHODS: We relied on an institutional tertiary-care database to identify mHSPC and subsequent mCRPC patients. The main outcome consisted of time to mCRPC and OS. Patients were stratified according to De Novo vs. secondary and low vs. high volume mHSPC and mCRPC, respectively. RESULTS: Of 504 mHSPC patients, 371 (73.6%) were De Novo vs. 133 (26.4%) secondary mHSPC. Patients with De Novo and high volume mHSPC harbored shorter time to mCRPC and OS than secondary and low volume mHSPC patients (both P < 0.01). After stratification regarding disease volume, median time to mCRPC differed significantly between De Novo high volume (DNHV) vs. De Novo low volume (DNLV) vs. secondary high volume (SecHV) vs. secondary low volume mHSPC patients (SecLV, P < 0.001). Similarly in OS analyses, median OS was 44 vs. 53 vs. 88 vs. 120 months for respectively DNHV vs. SecHV vs. SecLV vs. DNLV mHSPC (P < 0.001). After progression to mCRPC, the effect of onset of metastatic disease and metastatic volume was still observed (all P < 0.01). CONCLUSION: Patients with DNHV mHSPC harbor worse prognosis in a real world setting and in the light of combination therapies. This effect is also discernible in the context of mCRPC.

Influence of Tumor Characteristics and Time to Metastatic Disease on Oncological Outcomes in Metachronous Metastatic Prostate Cancer Patients.

INTRODUCTION: 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. PATIENTS AND 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. CONCLUSION: 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.

Outcomes of First-Line Abiraterone Acetate or Enzalutamide for Older Adults With Metastatic Castration-Resistant Prostate Cancer According to Use of Upfront Docetaxel for Metastatic Castration-Sensitive Prostate Cancer in an International Multicenter Registry: A SPARTACUSS-Meet-URO 26 Study.

BACKGROUND: Managing metastatic castration-resistant prostate cancer (mCRPC) in men aged ≥ 75 is challenging due to limited data. Regardless of age, in real-world clinical practice, most mCRPC still derive from failure of androgen deprivation therapy (ADT) with or without docetaxel (D) for metastatic castration-sensitive prostate cancer (mCSPC). As abiraterone acetate plus prednisone (AA) and enzalutamide (Enza) are common first-line treatments for mCRPC. The impact of prior use of D for mCSPC on the efficacy and safety of AA or Enza in this older population remains unclear. METHODS: A cohort of patients aged ≥ 75 years starting AA or Enza as first-line therapy for mCRPC from January 2015 to April 2019 was identified from the registries of 10 institutions. Patients were categorized into 2 groups based on previous use of D for mCSPC. Primary endpoints were cancer-specific survival (CSS) from AA or Enza start, CSS from ADT onset, and safety. We used Kaplan-Meier method to estimate the endpoints distribution, including median values with 95% confidence intervals (95% CI). RESULTS: Of the 337 patients identified, 24 (7.1%) received ADT+D and 313 (92.9%) received ADT alone for mCSPC. Median follow-up from AA/Enza start was 18.8 months. Median CSS from ADT or AA/Enza was not significantly different between ADT+D and ADT alone cohorts (71.9 vs. 52.7 months, P = .97; 25.4 vs. 27.2 months, P = .89, respectively). No statistically significant difference in adverse events (AEs) of any grade rate (58.3% vs. 52.1%, respectively; P = .67) or grade ≥ 3 (12.5% vs. 15.7%, respectively; P = 1.0) was found between ADT+D and ADT alone cohorts. CONCLUSIONS: Despite the innate limitations of a retrospective design and relatively small size of the ADT+D cohort, this analysis suggests that elderly men receiving AA or Enza as first-line therapy for mCRPC have similar survival outcomes and tolerability, regardless of previous D for mCSPC.

Correlation analyses of radiographic progression-free survival with clinical and health-related quality of life outcomes in metastatic castration-resistant prostate cancer: Analysis of the phase 3 VISION trial.

BACKGROUND: [177Lu]Lu-PSMA-617 (177Lu-PSMA-617) plus protocol-permitted standard of care (SOC) prolonged overall survival (OS) and radiographic progression-free survival (rPFS) versus SOC in patients with prostate-specific membrane antigen (PSMA)-positive metastatic castration-resistant prostate cancer (mCRPC) in the phase 3 VISION study, in addition to beneficial effects on symptomatic skeletal events (SSEs) and health-related quality of life (HRQOL). METHODS: Post hoc analyses used the full analysis set from the VISION study (N = 831) overall and by randomized treatment arm (177Lu-PSMA-617 plus SOC, n = 551; SOC, n = 280). Correlations were determined between OS and rPFS and between rPFS or OS and time to SSE or to worsening HRQOL (Functional Assessment of Cancer Therapy-Prostate [FACT-P] and 5-level EQ-5D [EQ-5D-5L]). Correlation analyses used an iterative multiple imputation copula-based approach (correlation coefficients [rho] of <0.3 were defined as weak, ≥0.3 and <0.5 as mild, ≥0.5 and <0.7 as moderate, and ≥0.7 as strong). RESULTS: In the overall population, rPFS correlated strongly with OS (rho, ≥0.7). Correlations between rPFS or OS and time to SSE without death were weak or mild. Time to worsening in the FACT-P total score and emotional and physical well-being domains correlated mildly or moderately with rPFS and moderately with OS. Correlation coefficients for time-to-worsening EQ-5D-5L scores were mild to moderate for both rPFS and OS. Correlation coefficients were similar between treatment arms. CONCLUSIONS: In this analysis of the VISION study, rPFS correlated strongly with OS but not with time to SSE or worsening HRQOL. These findings require further investigation.

Efficacy and safety of rechallenge [177Lu]Lu-PSMA-617 RLT after initial partial remission in patients with mCRPC: evaluation of a prospective registry (REALITY study).

AIM: 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. CONCLUSION: [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.