[177Lu]Lu-PSMA-617 plus enzalutamide in patients with metastatic castration-resistant prostate cancer (ENZA-p): an open-label, multicentre, randomised, phase 2 trial

State of the Art: Personalizing Treatment for Patients With Metastatic Castration-Resistant Prostate Cancer

Until recently, the treatment of metastatic castration-resistant prostate cancer (mCRPC) relied exclusively on hormonal therapies and taxane chemotherapy. The advent of modern molecular profiling methods applied in the clinic, namely, next-generation sequencing and advanced positron emission tomography (PET) imaging, has allowed for the development of biomarker-driven therapeutics including anti-PD-L1 therapy for microsatellite instability-high or tumor mutation burden-high disease, poly(ADP-ribose) polymerase (PARP) inhibitors for patients with DNA damage repair mutations, and lutetium 177 vipivotide tetraxetan (177Lu-PSMA-617) for patients with prostate-specific membrane antigen (PSMA) PET-avid disease. While these targeted therapies have improved outcomes, there is an opportunity to refine biomarkers to optimize patient selection, understand resistance, and develop novel combination strategies. In addition, studies in the laboratory and in patient-derived samples have shown that a subset of mCRPC tumors lose expression of common prostate cancer markers such as prostate-specific antigen and PSMA because of lineage plasticity and the development of non-androgen receptor (AR)-driven disease. Non-AR-driven prostate cancer has been associated with aggressive behavior and poor prognosis, including in some cases histologic transformation to a poorly differentiated neuroendocrine prostate cancer (NEPC). The clinical management of NEPC typically follows the treatment paradigm for small cell lung cancer and increasingly relies on genomic and phenotypic characterization of disease, including loss of tumor suppressors and expression of cell surface markers such as DLL3. Therefore, both genomic subtyping and phenotypic subtyping are important to consider and can guide the clinical management of patients with advanced prostate cancer.

The Role of SPECT/CT in 177Lu-PSMA-617 Theranostics: Case-based Review of Response and Progression Patterns

Lutetium-177 prostate-specific membrane antigen-617 (Lu-PSMA) has demonstrated efficacy in improving progression-free survival and overall survival in patients with metastatic castration-resistant prostate cancer (mCRPC). Post-treatment single photon emission tomography/computed tomography (SPECT/CT) imaging is an emerging tool for monitoring treatment response, enabling the tracking of functional changes during therapy. While quantitative SPECT analysis can predict patient outcomes, qualitative assessments are more practical and time-efficient in clinical settings. This case-based review examines treatment responses based on post-treatment SPECT/CT imaging, categorizing them into favorable response, progression, and mixed response patterns to improve interpretation and guide therapeutic adjustments, aiming to optimize management of mCRPC with Lu-PSMA therapy.

Current androgen receptor antagonists under investigation for resistant prostate cancer: progress and challenges

INTRODUCTION

Prostate cancer represents a significant oncological challenge, with its natural history predominantly driven by androgen receptor (AR) signaling. The pivotal role of this pathway underscores the rationale for targeting AR activity in therapeutic strategies. However, the development of resistance mechanisms has highlighted the need for advanced therapies to address the complexity of the castration-resistant status.

AREAS COVERED

We analyzed the evolving role of second-generation androgen receptor signaling inhibitors (ARSIs) in the management of non-metastatic and metastatic castration-resistant prostate cancer, we critically examine emerging combination strategies involving ARSIs, novel agents targeting resistance pathways, and the mechanisms underlying treatment resistance. The review also provides insights into future directions for enhancing outcomes. PubMed literature research using keywords related to castration-resistant prostate cancer and its treatments was performed, including the most relevant trials and reviews.

EXPERT OPINION

ARSIs have revolutionized the management of prostate cancer, providing substantial clinical benefits and representing the cornerstone of current treatment paradigms. However, key challenges remain, including determining optimal treatment sequencing, overcoming resistance mechanisms, and tailoring therapies to specific molecular subtypes. Biomarker-driven approaches are critical for refining patient selection and improving therapeutic outcomes. Ongoing trials investigating novel hormonal-axis-directed agents and innovative combination therapies aim to expand the arsenal of effective treatment.

Highlights of recent research focused on the treatment of advanced prostate cancer

PURPOSE OF REVIEW

This review is designed to highlight recent research focused on improving outcomes in men with advanced prostate cancer.

RECENT FINDINGS

Recent randomized trials have suggested advantages to treating men with advanced prostate cancer earlier in their disease course with novel hormonal agents and in some cases chemotherapy. Work remains to identify the optimal sequence of systemic therapies for metastatic prostate cancer with a focus on biomarkers that might select men in need of novel therapeutics. Some men with oligometastatic disease may benefit from localized therapy to sites of isolated progression and research continues to focus on optimally selecting these men. Radiopharmaceuticals are changing the treatment paradigm in advanced prostate cancer with efforts ongoing to improve outcomes with better biomarkers for response and novel treatment combinations.

SUMMARY

Ongoing research focuses on refining the use of existing therapeutics and developing novel treatments and combinations for men with advanced prostate cancer.

Lutetium-177 PSMA radioligand therapy in taxan-naive first- and second-line metastatic castration resistant prostate cancer after first-line ARPI therapy

PURPOSE

Lutetium-177 Prostate-specific membrane antigen (Lu-PSMA) radioligand therapy is EMA-approved for metastatic castration resistant prostate cancer (mCRPC) after androgen receptor pathway inhibition (ARPI) and taxan-based chemotherapy. However, its effect in taxan-naïve patients is under current investigation.

METHODS

We relied on the FRAMCAP database to elaborate Lu-PSMA therapy outcomes of progression-free (PFS) and overall (OS) in taxan-naïve mCRPC patients after previous ARPI treatment. Comparison was made against current standard of care with ARPI or docetaxel, irrespective of the previous used staging modality.

RESULTS

Of 269 patients, 11% received Lu-PSMA in first/second-line mCRPC vs. 57% ARPI vs. 33% docetaxel. Mostly no significant baseline differences between Lu-PSMA and ARPI patients were observed, while Lu-PSMA patients were significantly older, received less systematic treatments and ECOG1-2 proportions were higher, relative to docetaxel patients. In PFS (13.3 vs. 8.2 months, hazard ratio [HR]: 0.70, p = 0.16) and OS analyses (68.9 vs. 39.1 months, HR: 0.64, p = 0.2), Lu-PSMA was numerically more favorable than ARPI. In additional multivariable Cox regression models, Lu-PSMA was significant better regarding PFS and OS, relative to ARPI (both p < 0.05). Compared to docetaxel, also significant better PFS (13.3 vs. 8.1 months, HR: 0.46) and OS (68.9 vs. 27.3 months, HR: 0.34, both p < 0.01) was observed for Lu-PSMA treatment. The OS advantage was also observed after multivariable adjustment (p < 0.01).

CONCLUSION

This retrospective single-center study including a substantial proportion of patients with treatment preference for Lu-PSMA suggests that Lu-PSMA therapy provides significantly more favorable PFS and OS outcomes in taxan-naïve mCRPC patients after previous ARPI treatment, relative to ARPI or docetaxel treatment and may be considered as an early mCRPC treatment option.

Comparison of Radionuclide Drug Conjugates With Boron Neutron Capture Therapy: An Overview of Targeted Charged Particle Radiation Therapy

Targeted charged alpha- and beta-particle therapies are currently being used in clinical radiation treatments as newly developed methods for either killing or controlling tumor cell growth. The alpha particles can be generated either through a nuclear decay reaction or in situ by a nuclear fission reaction such as the boron neutron capture reaction. Different strategies have been employed to improve the selectivity and delivery of radiation dose to tumor cells based on the source of the clinically used alpha particles. As a result, the side effects of the treatment can be minimized. The increasing attention and research efforts on targeted alpha-particle therapy have been fueled by exciting results of both academic research and clinical trials. It is highly anticipated that alpha-particle therapy will improve the efficacy of treating malignant tumors. In this overview, we compare radionuclide drug conjugates (RDC) with boron neutron capture therapy (BNCT) to present recent developments in targeted alpha-particle therapy.

PSMA-based Therapies and Novel Therapies in Advanced Prostate Cancer: The Now and the Future

OPINION STATEMENT

The treatment landscape for metastatic castration-resistant prostate cancer (mCRPC) is rapidly evolving with the advent of PSMA-targeted radioligand therapies (RLTs) and bispecific T-cell engagers (BiTEs). These novel approaches provide new hope for patients who have progressed on standard therapies. However, their full clinical potential will be realized only by addressing key challenges, including tumor heterogeneity, resistance mechanisms, immune-related toxicities, and the immunosuppressive tumor microenvironment. Additionally, the optimal sequencing of these therapies at different stages of disease remains an open question. While most of these interventions are currently introduced in late-stage, heavily pretreated patients, ongoing clinical trials are exploring their role in earlier disease settings, where they may be more effective in altering the natural history of disease. PSMA-based RLTs, such as 177Lu-PSMA- 617, have demonstrated promising efficacy, particularly in patients with high PSMA expression. However, the presence of PSMA-negative or heterogeneous tumors necessitates the development of additional biomarkers and combination strategies. The ongoing PSMAddition trial may establish RLTs as an earlier-line treatment in hormone-sensitive metastatic prostate cancer, potentially shifting the standard of care. Moreover, mitigating toxicities through radioprotective agents may aid in expanding their clinical utility. BiTE therapies offer a different but complementary mechanism of action, leveraging T-cell engagement to drive tumor cell destruction. While cytokine release syndrome (CRS) and immunogenicity remain significant hurdles, modifications such as low-affinity CD3 binding and optimized dosing regimens are showing promise. The potential synergy of BiTEs with immune checkpoint inhibitors and tumor microenvironment-modulating agents should be further explored to enhance therapeutic efficacy. Given these advancements, the future of mCRPC treatment likely lies in a personalized, multimodal approach that integrates PSMA-based RLTs, BiTEs, and complementary therapies at earlier disease stages. Strategic biomarker-driven patient selection and combination regimens will be essential in optimizing outcomes while minimizing resistance and toxicity.

Systemic treatment options for metastatic castration resistant prostate cancer: A living systematic review

Background

Optimal treatment selection for metastatic castration resistant prostate cancer (mCRPC) remains challenging due to evolving standards of care in castration sensitive setting.

Purpose

To synthesize and appraise evidence on systemic therapy for mCRPC patients stratified by prior therapy and HRR alterations informing a clinical practice guideline.

Data Sources

MEDLINE and EMBASE (inception to 5 March 2025) using living search.

Study Selection

Randomized clinical trials assessing systemic therapy in mCRPC.

Data Extraction

Primary outcomes assessed were progression free survival (PFS) and overall survival (OS).

Data Synthesis

This report of the living systematic review (LSR) includes 143 trials with 17,523 patients (59 phase III/IV trials, 8,941 patients; 84 phase II, 8,582 patients). In the setting of prior androgen deprivation therapy (ADT) alone or ADT+docetaxel, treatment benefit was observed with poly (ADP-ribose) polymerase inhibitors (PARPi) in combination with androgen receptor pathway inhibitors (ARPI) for BRCA+ subgroup. In the setting of prior ADT+ARPI or ADT+ARPI+docetaxel, treatment benefit was observed with PARPi monotherapy for BRCA+ subgroup. Treatment benefit with PARPi may be observed for select non-BRCA homologous recombination repair (HRR) alterations (CDK12, PALB2). Treatment benefit was observed with abiraterone, enzalutamide, cabazitaxel, docetaxel (if no prior docetaxel), and Lu177 (if PSMA+) for patients without HRR alterations.

Limitations

Study-level data and indirectness in evidence.

Conclusion

Findings from the current LSR suggest that optimal treatment for mCRPC should be individualized based on prior therapy and HRR alterations. Current evidence favors PARPi alone (ARPI exposed) or in combination with ARPI (ARPI naïve) for patients with BRCA alterations, while ARPI alone, chemotherapy, and Lu177 remain potential options for patients without HRR alterations.

Clinical Trial Protocol for LuCAB: A Phase I-II Trial Evaluating Cabazitaxel in Combination with [177Lu]Lu-PSMA-617 in Patients with Metastatic Castration-Resistant Prostate Cancer

[177Lu]Lu-prostate-specific membrane antigen (PSMA)-617 is a standard treatment for patients with metastatic castration-resistant prostate cancer (mCRPC) previously treated with docetaxel and an androgen receptor pathway inhibitor. However, for many, responses are short and progression is inevitable. Contributing factors to treatment resistance include molecular heterogeneity with variable PSMA expression, micrometastases that may not absorb sufficient radiation from 177Lu to result in cell death, and inherent or acquired radioresistance because of genomic alterations or the tumor microenvironment. Cabazitaxel is a radiosensitizer and may treat PSMA-negative disease that would otherwise evade targeting by [177Lu]Lu-PSMA-617. We hypothesize that the combination of [177Lu]Lu-PSMA-617 and cabazitaxel will be synergistic with an acceptable safety profile. Methods: This investigator-initiated phase I-II trial aims to evaluate the safety, tolerability, and preliminary efficacy of cabazitaxel and [177Lu]Lu-PSMA-617 in combination. Up to 38 patients with mCRPC will receive up to 6 doses of [177Lu]Lu-PSMA-617 administered intravenously every 6 wk at a fixed dose of 7.4 GBq. Cabazitaxel will be administered concurrently (dose range, 12.5-20 mg/m2) on day 2 and day 23 of each 6-wk cycle, with dose escalation determined using a traditional 3 + 3 design to establish the maximum tolerated or administered dose. Key eligibility criteria include a diagnosis of progressive mCRPC with PSMA-positive disease on PSMA PET/CT (SUVmax ≥ 15) and no sites of discordance on [18F]F-FDG PET/CT. Patients must have received prior docetaxel and an androgen receptor pathway inhibitor, have adequate bone marrow and organ function, and have an Eastern Cooperative Oncology Group performance status of 0 or 1. The primary objective is to assess for dose-limiting toxicities and determine the recommended phase II dose of cabazitaxel and [177Lu]Lu-PSMA-617 in combination. Secondary objectives include further safety evaluation through the measurement of the frequency and severity of adverse events, assessment of efficacy, and evaluation of changes in pain and health-related quality of life over the first 12 mo from treatment commencement. Plasma will be collected at baseline, during treatment, and at disease progression for circulating tumor DNA analysis, which will be correlated with clinical outcomes to identify potential biomarkers of treatment response or resistance. Conclusion: Enrollment commenced in August 2022, with anticipated completion in 2025.

Current Approaches to Radiation Oncology Target Volume Delineation Using PET/Computed Tomography

PET is a versatile imaging modality widely used in oncology for diagnosing, staging, predicting outcomes, and surveillance for a variety of cancers. In radiation oncology, combining PET and computed tomography imaging can markedly enhance treatment planning through improved target volume delineation. This review examines data and clinical approaches across 3 major cancer types to evaluate the role of PET in target volume delineation, with data and current approaches for thoracic, genitourinary, and head and neck malignancies detailed. Additionally, it emphasizes various practical applications of PET in radiation therapy planning, several of which have been recently demonstrated in clinical trials.

Exploring the Flare Phenomenon in Patients with Castration-Resistant Prostate Cancer: Enzalutamide-Induced PSMA Upregulation Observed on PSMA PET

Androgen receptor-targeting agents, particularly enzalutamide, show promise in enhancing prostate cancer diagnostic and therapeutic strategies by modulating prostate-specific membrane antigen (PSMA). Methods: A retrospective clinical cohort study investigated 9 men with metastatic castration-resistant prostate cancer on enzalutamide. PSMA PET/CT scans were obtained before and after enzalutamide initiation to assess PSMA expression changes. Lesions and organs at risk were evaluated visually and semiquantitatively. The flare phenomenon was characterized by a significant increase (≥20%) in the SUVmax of existing lesions or the appearance of new PSMA-positive lesions. Results: Exposure to enzalutamide led to a significant PSMA expression increase in 56% of assessed lesions (n = 42), with new lesions detected in 1 patient (11%). PSMA expression in organs at risk remained largely unaffected, indicating a tumor-specific response. Conclusion: Enzalutamide induces PSMA upregulation in metastatic castration-resistant prostate cancer, potentially enhancing diagnostic and therapeutic strategies. Further exploration of the flare phenomenon's clinical implications is warranted.

Overall survival and quality of life with [177Lu]Lu-PSMA-617 plus enzalutamide versus enzalutamide alone in metastatic castration-resistant prostate cancer (ENZA-p): secondary outcomes from a multicentre, open-label, randomised, phase 2 trial

BACKGROUND

Interim analysis of the ENZA-p trial showed improved prostate-specific antigen (PSA) progression-free survival with the addition of lutetium-177 [177Lu]Lu-prostate-specific membrane antigen (PSMA)-617 to enzalutamide as first-line treatment of metastatic castration-resistant prostate cancer. Here, we report the secondary endpoints of overall survival and health-related quality of life (HRQOL) with longer follow-up.

METHODS

ENZA-p was a multicentre, open-label, randomised, phase 2 trial done at 15 hospitals in Australia. Participants were men aged 18 years or older who had not previously been treated with docetaxel or androgen receptor pathway inhibitors for metastatic castration-resistant prostate cancer, gallium-68 [68Ga]Ga PSMA-PET-CT-positive disease, an Eastern Cooperative Oncology Group performance status of 0-2, and at least two risk factors for early progression on enzalutamide. Participants were randomly assigned (1:1) by a centralised, web-based system using minimisation with a random component to stratify for study site, disease burden, early docetaxel, and previous treatment with abiraterone. Treatment was oral enzalutamide 160 mg daily alone or with adaptive-dosed (two or four doses) intravenous 7·5 GBq [177Lu]Lu-PSMA-617 every 6-8 weeks. The primary endpoint was prostate-specific antigen (PSA) progression-free survival, which has been previously reported. Overall survival, defined as the interval from the date of randomisation to date of death from any cause, or the date last known alive, and HRQOL were key secondary endpoints. HRQOL was assessed with the European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire Core 30 (QLQ-C30) and the Patient Disease and Treatment Assessment Form. For HRQOL analyses, deterioration-free survival was measured from randomisation until the earliest occurrence of death, clinical progression, discontinuation of study treatment; or a worsening of 10 points or more from baseline in physical function, or in overall health and QOL. Analyses of these secondary endpoints were prespecified and are by intention to treat. The trial is registered with ClinicalTrials.gov, NCT04419402, and follow-up is complete.

FINDINGS

Between Aug 17, 2020, and July 26, 2022, 79 patients were randomly assigned to enzalutamide and 83 to enzalutamide plus [177Lu]Lu-PSMA-617. 96 deaths was reported after a median follow-up of 34 months (IQR 29-39): 53 (67%) in the enzalutamide group and 43 (52%) in the enzalutamide plus [177Lu]Lu-PSMA-617 group. Overall survival was longer in the enzalutamide plus [177Lu]Lu-PSMA-617 group than the enzalutamide group (median 34 months [95% CI 30-37] vs 26 months [23-31]; HR 0·55 [95% CI 0·36-0·84], log-rank p=0·0053). HRQOL was rated by 154 (95%) of 162 participants. Deterioration-free survival at 12 months and stratified log-rank p values favoured enzalutamide plus [177Lu]Lu-PSMA-617 for both physical function (median 10·64 months [95% CI 7·66-12·42] vs 3·42 months [3·19-7·89]; HR 0·51 [95% CI 0·36-0·72], log-rank p<0·0001) and overall health and QOL (8·71 months [6·41-11·56] vs 3·32 months [3·09-5·26]; HR 0·47 [95% CI 0·33-0·67], log-rank p=0·0001). Mean scores for pain until progression favoured enzalutamide plus [177Lu]Lu-PSMA-617 over enzalutamide (difference 7·3 [95% CI 1·6-12·9]; p=0·012). Mean scores for fatigue until progression favoured enzalutamide plus [177Lu]Lu-PSMA-617 over enzalutamide (difference 5·9 [95% CI 1·1-10·7]; p=0·016). The frequency of self-rated xerostomia was lower in the enzalutamide group than in the enzalutamide plus [177Lu]Lu-PSMA-617 group (43 [57%] of 75 vs 58 [74%] of 78; p=0·039), and scores were not significantly different between groups for all other domains. Grade 3-5 adverse events occurred in 35 (44%) of 79 patients in the enzalutamide group and 37 (46%) of 81 patients in the enzalutamide plus [177Lu]Lu-PSMA-617 group. No deaths were attributed to study treatment in either group.

INTERPRETATION

The addition of [177Lu] Lu-PSMA-617 to enzalutamide was associated with improved survival and some aspects of HRQOL in patients with high-risk metastatic castration-resistant prostate cancer. Our findings warrant phase 3 evaluation of adaptive-dosed [177Lu] Lu-PSMA-617 in combination with androgen receptor pathway inhibitors in people with metastatic prostate cancer.

FUNDING

The Prostate Cancer Research Alliance initiative (Movember and Australian Federal Government), St Vincent's Clinic Foundation, GenesisCare, RoyMorgan, AdAcAp (a Novartis company), and Astellas.

Comparative therapeutic efficacy and safety of first-line and second-line therapies for metastatic castration-resistant prostate cancer: a systematic review and network meta-analysis

Background

There is no cross-sectional comparison on therapeutic and adverse effects for treatments of metastatic castration-resistant prostate cancer (mCRPCa). We aimed to horizontally compare them for all common first-line and second-line therapies.

Methods

We conducted a network meta-analysis with a systematic review in four databases (Pubmed, Web of Science, Embase, and Cochrane Library) up to January 5th, 2025. All randomized controlled trials (RCT) related to mCRPCa treatments with a clear description in study design were included. Endpoints included the radiographic progression-free survival (rPFS), overall survival (OS), time to PSA progression (TTPP), PSA progression rate (PSARR), and adverse events. All data was extracted by two researchers and analyzed with Gemtc package in R and Stata15. This NMA protocol was registered online (ID: CRD42025633178).

Findings

After screening among 33,694 articles, 24 RCTs involving 13,059 cases were included. For first-line treatments, combination therapies with second-generation androgen receptor inhibitors (ARIs) showed superior efficacies in OS [HR of poly(ADP-ribose) polymerase inhibitors (PARPi) + ARI: 0.63 (0.32,1.25)], TTPP [HR of Lu177 + ARI: 0.07 (0.01,0.87)] and PSARR [RR of Lu177 + ARI: 33.02 (15.56,71.62)] with the highest SUCRA (Surface under the Cumulative Ranking Curve) (72%, 91% and 97% respectively). PARPi + ARI also performed best for rPFS (SUCRA: 85%, with an insignificant HR [0.12 (0.02,2.35)]. For post-docetaxel second-line treatments, ARI also emerged as the preferred option. Efficacies of post-ARI second-line treatments were not evaluated due to the lack of related RCTs. No obvious heterogeneity and publication bias was detected during the therapeutic comparison.

Interpretation

This study provided comparative evidence for first-line and post-chemotherapy second-line mCRPCa treatment options. Second-generation ARIs exhibited good efficacy, particularly when combined with other treatments. However, the safety analysis necessitated balance between benefits and adverse events, especially for combination therapies. Stronger evidence is needed through direct comparisons in future clinical trials.

Funding

The study was supported by The National Natural Science Foundation of China (No. 82172568).

Management Based on Pretreatment PSMA PET of Patients with Localized High-Risk Prostate Cancer Part 2: Prediction of Recurrence-A Systematic Review and Meta-Analysis

BACKGROUND AND OBJECTIVES

For patients with prostate cancer (PCa), PSMA PET better diagnose metastases than conventional imaging. In a systematic review and meta-analysis (INPLASY register, 2024311004), we aimed to summarize findings with pretreatment PSMA PET in patients with PCa that was localized according to conventional imaging and summarize how pretreatment PSMA PET had influence on biochemical recurrence (BCR)-free survival and overall survival (OS).

METHODS

We searched for publications in Pubmed, Google Scholar, ClinicalTrials.gov, and reference lists between 2016 and February 2025. We summarized biochemical recurrence-free survival in Forest plots.

RESULTS

Nine publications reported 1908 patients and showed that pretreatment PSMA PET was associated with survival. Three publications reported that pretreatment PSMA PET gave better 3-5-year BCR-free survival than conventional imaging (74% versus 57%). Two publications reported PSMA PET-risk for 389 patients. Those with PSMA PET-low-risk lived 5 years longer often than those with PSMA PET high-risk (84% versus 20%).

CONCLUSIONS

Pretreatment PSMA PET is widely used in the real world. Pretreatment PSMA PET supports personalized treatment and may explain why pretreatment PSMA PET improved BCR-free survival and OS. It is believed that pretreatment PSMA PET may facilitate future progress in care of patients with high-risk PCa.

Potential theranostics of breast cancer with copper-64/67 sarcophagine-trastuzumab

Over-expression of Human Epidermal Growth Factor Receptor 2 (HER2) is associated with a significant proportion of breast cancers. Targeting HER2 is possible with a monoclonal antibody called trastuzumab but metastatic HER2 positive tumours can develop resistance to this treatment. One approach to develop more potent therapeutic agents which retain the selectivity of trastuzumab is to attach a β- emitting radionuclide, such as copper-67, to the antibody for radioimmunotherapy. It is also possible to attach β+ emitting copper-64 to antibodies for diagnostic imaging with positron emission tomography (PET). In this work, a cage amine sarcophagine (Sar) chelator is conjugated to trastuzumab to give Sar-trastuzumab which can be radiolabelled with either copper-64 or copper-67 at room temperature in minutes to give [64Cu]CuSar-trastuzumab and [67Cu]CuSar-trastuzumab respectively. The diagnostic imaging potential of [64Cu]CuSar-trastuzumab was evaluated in mice bearing HER2+ SKOV-3 tumours showing that the tracer has very high tumour uptake and retention 48 hours after injection. The copper-67 variant, [67Cu]CuSar-trastuzumab, was highly therapeutically efficacious in the same tumour model with no signs of radiotoxicity. The combination of diagnostic PET imaging with [64Cu]CuSar-trastuzumab to guide radionuclide therapy with [67Cu]CuSar-trastzumab has significant potential for theranostic treatment of breast cancer and other HER2+ disease that has become resistant to conventional immunotherapy.

Treatment of metastatic castration-resistant prostate cancer: review of current evidence and synthesis of expert opinions on radioligand therapy

Background

Despite the boom in the development of cancer management in the last decade, most patients with metastatic prostate cancer (PCa) eventually progress to metastatic castration-resistant PCa (mCRPC) and often require multiple lines of treatment. The treatment landscape of mCRPC has evolved rapidly in recent years, introducing various types of systemic therapies, including taxane-based chemotherapy, androgen receptor pathway inhibitors, bone-targeted radionuclides (e.g., radium-223), immune checkpoint inhibitors, poly(adenosine diphosphate [ADP]-ribose) polymerase (PARP) inhibitors, and radioligand therapies (RLTs) [e.g., a prostate-specific membrane antigen (PSMA) ligand labelled with 177Lu].

Methods

To help clinicians navigate the increasingly complex treatment landscape of mCRPC, this article reviews the evidence on different therapeutic regimens from pivotal trials. In addition, it reports on the results of a questionnaire developed and distributed by the Hong Kong Society of Uro-Oncology (HKSUO), with the aim of collecting the perspectives of specialists experienced in the treatment of advanced PCa in Hong Kong with regard to the clinical application of RLT, primarily [177Lu]Lu-PSMA-617/analogue therapy.

Results

A total of 43 questionnaire respondents (including clinical oncologists, urologists, nuclear medicine specialists, and medical oncologists) voted on 27 consensus questions divided into eight sections. Consensus or strong consensus (correspondingly ≥75% or ≥90% acceptance for an answer option) was reached for 10 questions. Subsequently, a panel of 13 local and overseas experts coordinated by the HKSUO discussed the voting results and provided further insights into certain questions.

Conclusion

The literature review, the voting results of the questionnaire, and the expert opinions are expected to facilitate better understanding of recent therapeutic advancements and the role of novel RLTs in the treatment of mCRPC among clinicians.

Efficacy of 177Lu-PSMA-617 Therapy in mCRPC Patients with Liver Metastases: Insights into Survival Outcomes and Predictors of Response

Objectives: Metastatic castration-resistant prostate cancer (mCRPC) is associated with poor prognosis, particularly in cases of liver metastases. 177Lu-PSMA-617 (commercially known as Pluvicto) is an FDA-approved radioligand therapy for mCRPC patients. This study aimed to evaluate the efficacy of 177Lu-PSMA-617 radioligand therapy (RLT) in mCRPC patients with liver metastases, focusing on progression-free survival (PFS), overall survival (OS), and factors influencing treatment response. Materials and Methods: This retrospective study included mCRPC patients (n = 32) with liver metastases treated with Lu-PSMA-617. Patient data, including prostate-specific antigen (PSA) levels, liver SUVmax values, Lutetium-PSMA therapy cycles, and survival outcomes, were collected. Kaplan-Meier survival analysis was used to calculate PFS and OS, while regression analysis was employed to identify factors associated with treatment response. Results: The median PFS and OS were 6 and 9 months, respectively. Partial regression was observed in patients with significantly lower PSA levels (median: 90.0 ng/mL, range: 22-699 ng/mL, p = 0.001) and liver SUVmax values (median: 17.9, range: 8.3-57.0, p = 0.008). A higher number of Lutetium-PSMA cycles correlated with improved treatment response (p = 0.010) and reduced liver SUVmax values (p = 0.043). Conclusions: Lu-PSMA-617 therapy is effective in managing mCRPC with liver metastases. Increased intensity of therapy exposure, reflected by a higher number of treatment cycles, is associated with a greater biochemical response, as indicated by reduced PSA levels, thereby supporting the rationale for personalized treatment strategies. These findings support the use of Lu-PSMA-617 in mCRPC patients with liver metastases, warranting further prospective studies.

Molecular Imaging for Biomimetic Nanomedicine in Cancer Therapy: Current Insights and Challenges

Coating biological membranes onto biomimetic nanocarriers improves biocompatibility, prolongs circulation, and enhances targeted delivery for cancer precision medicine. To better understand the biodistribution profiles of these biomimetic nanosystems, molecular imaging techniques, including optical imaging, radionuclide imaging, magnetic resonance imaging, and ultrasound imaging, have been widely employed for in vivo tracking and dynamic imaging. Here in this review, we delve into the profound role of these imaging modalities in visualizing changes in the tumor microenvironment, particularly in monitoring oxygen consumption and immune response dynamics, highlighting their potential to improve cancer therapies. We also briefly discuss current applications of molecular imaging in synergistic cancer therapies and future perspectives. Finally, we offer insights into the potential of integrating biomimetic nanomedicine with molecular imaging for clinical translation.

The role of PSMA-based radioligand therapy in hormone-sensitive prostate cancer

PURPOSE

Conventional systemic therapies are valuable options in prostate cancer (PCa); however, such treatments can determine adverse events and toxicity. The observed improvement in overall survival, coupled with PSA reduction and a favorable safety profile in the post-taxane castration-resistant PCa (CRPC) setting has prompted the consideration of PSMA-based radioligand therapy (RLT) earlier in the treatment sequence. In this review, we will describe the literature and ongoing clinical trials regarding the use of PSMA-based RLT in hormone-sensitive PCa (HSPC) including the neoadjuvant, de-novo/synchronous metastatic, adjuvant, and early BCR settings.

METHODS

We performed a systematic literature search on the PubMed/MEDLINE/EMBASE and clinicaltrials.gov databases for studies and protocols assessing the role of PSMA-based RLT in HSPC.

RESULTS

The literature search yielded 140 results. After screening titles and abstracts and applying inclusion and exclusion criteria, we selected 25 papers showing the potentialities of earlier RLT in HSPC, with several ongoing trials.

CONCLUSION

Early use of PSMA-based RLT holds significant potential in HSPC patients from the neoadjuvant to the BCR setting. In these stages, the lower tumor burden, more frequent exclusive nodal involvement, and higher organ reserve may improve treatment efficacy and allow for treatment combinations while maintaining a less toxic profile.

Association of Prior PARP Inhibitor Exposure with Clinical Outcomes after 177Lu-PSMA-617 in Men with Castration-resistant Prostate Cancer and Mutations in DNA Homologous Recombination Repair Genes

BACKGROUND AND OBJECTIVE

The prostate-specific membrane antigen (PSMA) radioligand 177Lu-PSMA-617 (LuPSMA) is approved for treatment of metastatic castration-resistant prostate cancer (mCRPC). PARP inhibitors (PARPi) are approved for patients with mCRPC and mutations in homologous recombination repair (HRR) pathway genes. Both modalities induce DNA damage and therefore may share mechanisms of resistance. We investigated whether PARPi exposure would reduce the subsequent efficacy of LuPSMA.

METHODS

This retrospective study included 100 patients with a PARPi-qualifying HRR alteration treated with LuPSMA. Clinical outcomes on LuPSMA, including PSA50 response, PSA progression-free survival (PFS), and overall survival (OS), were compared between those who had not previously received PARPi (PARPi-N) and those who had (PARPi-T). Subgroup analyses were performed for the most frequent HRR alterations (BRCA2 and ATM).

KEY FINDINGS AND LIMITATIONS

PSA50 responses on LuPSMA were similar between PARPi-N (n = 47) and PARPi-T (n = 53), although PSA PFS was longer in the PARPi-N group (9.1 vs 4.8 mo; p = 0.037). Among patients with BRCA2 alterations, the PARPi-N group had a better PSA50 response rate (89% vs 35%; p = 0.009), PSA PFS (14 vs 2.9 mo; p = 0.026), and OS (19 vs 5.3 mo; p = 0.10). PARPi exposure did not influence LuPSMA outcomes among patients with ATM alterations. Limitations include the retrospective design and differences in prior lines of therapy between the groups.

CONCLUSIONS AND CLINICAL IMPLICATIONS

PARPi exposure is associated with inferior LuPSMA outcomes, particularly for patients with BRCA2 alterations. These findings suggest potential cross-resistance and underscore the need for prospective studies assessing the optimal sequencing of these agents.

Management of Patients with Advanced Prostate Cancer. Report from the 2024 Advanced Prostate Cancer Consensus Conference (APCCC)

BACKGROUND AND OBJECTIVE

Innovations have improved outcomes in advanced prostate cancer (PC). Nonetheless, we continue to lack high-level evidence on a variety of topics that greatly impact daily practice. The 2024 Advanced Prostate Cancer Consensus Conference (APCCC) surveyed experts on key questions in clinical management in order to supplement evidence-based guidelines. Here we present voting results for questions from APCCC 2024.

METHODS

Before the conference, a panel of 120 international PC experts used a modified Delphi process to develop 183 multiple-choice consensus questions on eight different topics. Before the conference, these questions were administered via a web-based survey to the voting panel members ("panellists").

KEY FINDINGS AND LIMITATIONS

Consensus was a priori defined as ≥75% agreement, with strong consensus defined as ≥90% agreement. The voting results show varying degrees of consensus, as discussed in this article and detailed in the Supplementary material. These findings do not include a formal literature review or meta-analysis.

CONCLUSIONS AND CLINICAL IMPLICATIONS

The voting results can help physicians and patients navigate controversial areas of clinical management for which high-level evidence is scant or conflicting. The findings can also help funders and policymakers in prioritising areas for future research. Diagnostic and treatment decisions should always be individualised on the basis of patient and cancer characteristics, and should incorporate current and emerging clinical evidence, guidelines, and logistic and economic factors. Enrolment in clinical trials is always strongly encouraged. Importantly, APCCC 2024 once again identified important gaps (areas of nonconsensus) that merit evaluation in specifically designed trials.

Vesicles Secreted by Renal Cell Carcinoma Cells Cause Vascular Endothelial Cells to Express PSMA and Drive Tumor Progression

Prostate-specific membrane antigen (PSMA) protein expression is induced during prostate cancer progression and metastasis. Recently, we reported that PSMA-positive vesicles released by prostate cancer cell lines enhanced vascular endothelial cell angiogenesis and that PSMA may be involved in tumor angiogenesis. Similarly, it is known that PSMA is upregulated in peritumoral vessels in renal cell carcinoma (RCC). In this study, we investigated the significance and molecular function of PSMA in RCC. PSMA immunohistochemical staining confirmed PSMA presence only in perinephric tumor vessels, and PSMA intensity was strongly correlated with recurrence rate and venous invasion. Spatial gene expression analysis revealed that FOLH1 expression, which codes PSMA, was upregulated in tumor blood vessels around renal cancer, and that angiogenesis-related pathways were enhanced. The 10,000 g pellet fraction of the renal cancer cell lines Caki1- and ACHN-conditioned medium (CM) induced PSMA positivity in human umbilical vein endothelial cells (HUVECs) and enhanced tube formation. Mass spectrometry indicated that the 10,000 g pellet fraction contained various kinds of growth factors, like GDF15 and MYDGF. RNA sequencing showed that supplementing HUVECs with RCC cell CM-enhanced angiogenesis-related signaling pathways. Conclusively, microvesicle components secreted by RCC cells transform vascular endothelial cells into PSMA-positive cells, enhancing angiogenesis.

Defining the Position of [177Lu]Lu-PSMA Radioligand Therapy in the Treatment Landscape of Metastatic Castration-Resistant Prostate Cancer: A Meta-analysis of Clinical Trials

BACKGROUND

In recent years, theranostics has become a promising approach for treating metastatic castration-resistant prostate cancer (mCRPC), with trials investigating targeted radioligand therapy, particularly using prostate-specific membrane antigen labeled with lutetium-177 ([177Lu]Lu-PSMA). The proper position of [177Lu]Lu-PSMA in the therapeutic algorithm of mCRPC is yet to be identified.

DESIGN, SETTING, AND PARTICIPANTS

We conducted a systematic review and meta-analysis of phase II/III randomized controlled trials to assess the efficacy of [177Lu]Lu-PSMA in treating mCRPC. Study endpoints included radiographic progression-free survival (rPFS), prostate-specific antigen-PFS, objective response rate, and overall survival.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Data were extracted according to the PRISMA statement. Summary hazard ratios (HRs) were calculated using random- or fixed-effects models. Statistical analyses were performed with RevMan software (v.5.2.3).

RESULTS

[177Lu]Lu-PSMA reduced the risk of rPFS (HR 0.55; 95% confidence interval [CI] 0.43-0.71; p < 0.00001) and prostate-specific antigen-PFS (HR 0.53; 95% CI 0.41-0.67; p < 0.00001), and improved the objective response rate compared with control therapies (response rate 3.55; 95% CI 1.91-6.60; p < 0.0001), whereas no significant cumulative effect on overall survival was documented (HR 0.92; 95% CI 0.65-1.31; p = 0.63). Notably, in a dedicated subanalysis, comparable effects on rPFS were observed when [177Lu]Lu-PSMA was compared with active therapy.

CONCLUSION

[177Lu]Lu-PSMA has a favorable impact on the radiographic and biochemical control of mCRPC and represents a potential treatment in a scenario where other valuable options are available. Further efforts are required to identify clinical and molecular markers necessary for proper patient stratification.

Lutetium-177-prostate-specific membrane antigen therapy for prostate cancer: current status and future prospects

PURPOSE OF REVIEW

Lutetium-177-prostate-specific membrane antigen (Lu 177-PSMA) radioligand therapy has emerged as a promising novel strategy for advanced prostate cancer. With its increasing importance alongside with a plethora of exciting results from latest trials, we would like to summarize current evidence and advancements in Lu 177-PSMA therapy across different stages of prostate cancer.

RECENT FINDINGS

In metastatic castration-resistant prostate cancer (mCRPC), early studies like the LuPSMA trial and TheraP trial demonstrated promising PSA response rates. The landmark VISION trial had established the oncological efficacy of Lu 177-PSMA as salvage therapy and demonstrated its benefit on survival outcomes. Explorations into earlier treatment settings have also been encouraging. Studies like that the PSMAfore trial, Enza-P trial and the UpFrontPSMA trial explored an earlier role of Lu 177-PSMA in mCRPC, and showed benefits when used in solitary or in junction with Docetaxel or androgen receptor pathway inhibitor. Finally, the potential use of Lu 177-PSMA as neoadjuvant therapy in localized prostate cancer is also under consideration, whose safety was demonstrated in the recent LuTectomy trial.

SUMMARY

Lu 177-PSMA therapy represents a significant advancement in prostate cancer treatment, offering selective and targeted delivery of radiation to prostate cancer cells in patients across various disease stages. Ongoing research and collaborative efforts are essential to overcome existing challenges, optimize patient selection and integrate this therapy into standard clinical practice, ultimately improving outcomes for patients with advanced prostate cancer.

Intensification Approaches and Treatment Sequencing in Metastatic Castration-resistant Prostate Cancer: A Systematic Review

BACKGROUND AND OBJECTIVE

Recently, research on treatment intensification has gathered momentum, and three novel therapy combinations were approved for metastatic castration-resistant prostate cancer (mCRPC). This systematic review summarizes the current and emerging evidence around intensified strategies for mCRPC and provides guidance for an ideal therapeutic sequencing.

METHODS

Preferred Reporting Items for Systematic Review and Meta-analysis Protocols (PRISMA-P) guidelines were followed to perform this review. PubMed, EMBASE, Web of Science, Cochrane Library, ClinicalTrials.gov, and major international societies' online proceedings were searched comprehensively until May 15, 2024, for terms related to treatment intensification and sequencing for mCRPC.

KEY FINDINGS AND LIMITATIONS

Overall, 28 clinical trials and 24 ongoing studies of intensification treatments were included in this review. Algorithms of optimal sequencing of approved treatments for mCRPC were outlined according to the use of androgen receptor pathway inhibitors (ARPIs) with or without docetaxel for earlier disease states. In first line, poly(ADP-ribose) polymerase inhibitor + ARPI combinations improve radiographical progression-free survival (rPFS), particularly for those with BRCA1/2 alterations. The AKT inhibitor combination of ipatasertib + abiraterone extends rPFS in those with PTEN loss or PIK3CA/AKT1/PTEN alterations. In those with two or more risk factors for early progression on enzalutamide, radionuclide 177-Lu-PSMA-617 + enzalutamide prolongs progression-free survival. Ongoing research of intensified approaches for mCRPC, and available and potential predictive and prognostic biomarkers are discussed.

CONCLUSIONS AND CLINICAL IMPLICATIONS

Recent approvals and ongoing investigations of single agents and intensification approaches will keep transforming the mCRPC treatment landscape. Improvement of patient profiling applying recognized genomic, molecular, and clinical predictive and prognostic indicators is fundamental to optimize sequential use of available therapies.

Biological determinants of PSMA expression, regulation and heterogeneity in prostate cancer

Prostate-specific membrane antigen (PSMA) is an important cell-surface imaging biomarker and therapeutic target in prostate cancer. The PSMA-targeted theranostic 177Lu-PSMA-617 was approved in 2022 for men with PSMA-PET-positive metastatic castration-resistant prostate cancer. However, not all patients respond to PSMA-radioligand therapy, in part owing to the heterogeneity of PSMA expression in the tumour. The PSMA regulatory network is composed of a PSMA transcription complex, an upstream enhancer that loops to the FOLH1 (PSMA) gene promoter, intergenic enhancers and differentially methylated regions. Our understanding of the PSMA regulatory network and the mechanisms underlying PSMA suppression is evolving. Clinically, molecular imaging provides a unique window into PSMA dynamics that occur on therapy and with disease progression, although challenges arise owing to the limited resolution of PET. PSMA regulation and heterogeneity - including intertumoural and inter-patient heterogeneity, temporal changes, lineage dynamics and the tumour microenvironment - affect PSMA theranostics. PSMA response and resistance to radioligand therapy are mediated by a number of potential mechanisms, and complementary biomarkers beyond PSMA are under development. Understanding the biological determinants of cell surface target regulation and heterogeneity can inform precision medicine approaches to PSMA theranostics as well as other emerging therapies.

The therapeutic use of 177 Lu-PSMA-617 radioligand therapy in prostate cancer treatment: a review of literature and ongoing trials

Radioligand therapy is a targeted cancer treatment modality in which radioisotopes are utilized in the delivery of radiation at targeted cancer cells, with the goal of sparing normal cells. Prostate cancer is a well-known radiosensitive disease, historically treated with radioisotopes such as Strontium-89, Samarium-153, and Radium-223 for palliation of bone metastases. Recently, prostate specific membrane antigen (PSMA) has recently been employed as a radioligand target due to its unique properties of high expression on the surface of prostate cancer cells, limited expression in normal tissue, function as an internalizing cell surface receptor, and increased expression with androgen deprivation therapy. In 2015, 177Lu-PSMA-617 was first introduced as a promising treatment option for castration-resistant prostate cancer, and 7 years later the results of the phase III VISION trial led to 177Lu-PSMA-617 gaining FDA approval for the treatment of progressive castration-resistant prostate cancer. These results in combination with the inherent properties of 177Lu-PSMA-617 have led to its current exploration as a promising treatment modality beyond progressive metastatic castration-resistant prostate cancer, and into the earlier phases of prostate cancer. This review paper aims to highlight the key phase III randomized controlled trials related to 177Lu-PSMA-617 in all stages of prostate cancer, as well as bring attention to ongoing, earlier phase I/II trials incorporating 177Lu-PSMA-617.

Treatment intensification with radium-223 plus enzalutamide in patients with metastatic castration-resistant prostate cancer

Several life-prolonging therapies with diverse mechanisms of action (MoA) are available for the treatment of metastatic hormone-sensitive/castration-resistant prostate cancer, with many patients requiring multiple lines of therapy. Nevertheless, treatment optimization to further delay disease progression and improve overall survival remains an unmet need. Despite the number of agents with differing MoAs approved for advanced prostate cancer, many patients receive only one or two life-prolonging therapies. One strategy for enhancing the benefit of treatment for this aggressive disease is combining therapies with different MoAs (treatment intensification) early in the disease course, which may be more effective than administering therapies sequentially, yet still allow for subsequent sequential use of individual therapies to optimize patient outcomes. In this narrative review we discuss the rationale for combining 223radium dichloride (223Ra; an alpha-emitting radionuclide) with enzalutamide (an androgen receptor inhibitor) for treatment intensification, including their differing MoAs, their individual efficacy in this setting, and their largely non-overlapping tolerability profiles. We also summarize the preclinical and clinical data available for this combination to date, including interim safety data from the phase 3 EORTC 1333/PEACE III study which highlight the low fracture risk of 223Ra plus enzalutamide when administered concomitantly with bone health agents. Relevant data were sourced from clinical studies published by the authors and via searches of PubMed, clinical trial registries and congress abstracts.

Treatment response assessment in mCRPC: is PSMA-PET/CT going to take the lead?

The assessment of response to therapy in prostate cancer (PCa) patients is an ongoing, open issue. Prostate-specific antigen has limitations, especially in advanced metastatic PCa, which often displays intratumor variability in terms of response to therapy. Conventional imaging (i.e. computerized tomography and bone scan) is of limited use for its low sensitivity and specificity. Positron-emission tomography (PET) with prostate-specific membrane antigen (PSMA) demonstrated higher sensitivity and specificity, and novel PSMA-based criteria have been recently proposed for treatment response, with promising results in different scenarios, from chemotherapy to radioligand therapy. PSMA-based criteria have been found to outperform the current RECIST 1.1 and Prostate Cancer Working Group 3 frameworks in describing the behavior of PCa, precisely assessing tumor phenotypes through molecular-imaging-derived parameters. This review critically explores the current evidence about the role of PSMA PET/computed tomography in the assessment of treatment response.

The 30th Annual Prostate Cancer Foundation Scientific Retreat Report

BACKGROUND

The 30th Annual Prostate Cancer Foundation (PCF) Scientific Retreat was held at the Omni La Costa Resort in Carlsbad, CA, from October 26 to 28, 2023. A hybrid component was included for virtual attendees.

METHODS

The Annual PCF Scientific Retreat is a leading international scientific conference focused on pioneering, unpublished, and impactful studies across the spectrum of basic through clinical prostate cancer research, as well as research from related fields with significant potential for improving prostate cancer research and patient outcomes.

RESULTS

The 2023 PCF Retreat concentrated on key areas of research, including: (i) the biology of cancer stem cells and prostate cancer lineage plasticity; (ii) mechanisms of treatment resistance; (iii) emerging AI applications in diagnostic medicine; (iv) analytical and computational biology approaches in cancer research; (v) the role of nerves in prostate cancer; (vi) the biology of prostate cancer bone metastases; (vii) the contribution of ancestry and genomics to prostate cancer disparities; (viii) prostate cancer 3D genomics; (ix) progress in new targets and treatments for prostate cancer; (x) the biology and translational applications of tumor extracellular vesicles; (xi) updates from PCF TACTICAL Award teams; (xii) novel platforms for small molecule molecular glues and binding inhibitors; and (xiii) diversity, equity and inclusion strategies for advancing cancer care equity.

CONCLUSIONS

This meeting report summarizes the presentations and discussions from the 2023 PCF Scientific Retreat. We hope that sharing this information will deepen our understanding of current and emerging research and drive future advancements in prostate cancer patient care.

177Lu-PSMA-617 versus a change of androgen receptor pathway inhibitor therapy for taxane-naive patients with progressive metastatic castration-resistant prostate cancer (PSMAfore): a phase 3, randomised, controlled trial

BACKGROUND

[177Lu]Lu-PSMA-617 (177Lu-PSMA-617) prolongs radiographic progression-free survival and overall survival in patients with metastatic castration-resistant prostate cancer previously treated with androgen receptor pathway inhibitor (ARPI) and taxane therapy. We aimed to investigate the efficacy of 177Lu-PSMA-617 in patients with taxane-naive metastatic castration-resistant prostate cancer.

METHODS

In this phase 3, randomised, controlled trial conducted at 74 sites across Europe and North America, taxane-naive patients with prostate-specific membrane antigen (PSMA)-positive metastatic castration-resistant prostate cancer who had progressed once on a previous ARPI were randomly allocated (1:1) to open-label, intravenous 177Lu-PSMA-617 at a dosage of 7·4 GBq (200 mCi) ± 10% once every 6 weeks for six cycles, or a change of ARPI (to abiraterone or enzalutamide, administered orally on a continuous basis per product labelling). Crossover from ARPI change to 177Lu-PSMA-617 was allowed after centrally confirmed radiographic progression. The primary endpoint was radiographic progression-free survival, defined as the time from randomisation until radiographic progression or death, assessed in the intention-to-treat population. Safety was a secondary endpoint. This study is registered with ClinicalTrials.gov (NCT04689828) and is ongoing. In this primary report of the study, we present primary (first data cutoff) and updated (third data cutoff) analyses of radiographic progression-free survival; all other data are based on the third data cutoff.

FINDINGS

Overall, of the 585 patients screened, 468 met all eligibility criteria and were randomly allocated between June 15, 2021 and Oct 7, 2022 to receive 177Lu-PSMA-617 (234 [50%] patients) or ARPI change (234 [50%]). Baseline characteristics were mostly similar between groups; median number of 177Lu-PSMA-617 cycles was 6·0 (IQR 4·0-6·0). Of patients assigned to ARPI change, 134 (57%) crossed over to receive 177Lu-PSMA-617. In the primary analysis (median time from randomisation to first data cutoff 7·26 months [IQR 3·38-10·55]), the median radiographic progression-free survival was 9·30 months (95% CI 6·77-not estimable) in the 177Lu-PSMA-617 group versus 5·55 months (4·04-5·95) in the ARPI change group (hazard ratio [HR] 0·41 [95% CI 0·29-0·56]; p<0·0001). In the updated analysis at time of the third data cutoff (median time from randomisation to third data cutoff 24·11 months [IQR 20·24-27·40]), median radiographic progression-free survival was 11·60 months (95% CI 9·30-14·19) in the 177Lu-PSMA-617 group versus 5·59 months (4·21-5·95) in the ARPI change group (HR 0·49 [95% CI 0·39-0·61]). The incidence of grade 3-5 adverse events was lower in the 177Lu-PSMA-617 group (at least one event in 81 [36%] of 227 patients; four [2%] grade 5 [none treatment related]) than the ARPI change group (112 [48%] of 232; five [2%] grade 5 [one treatment related]).

INTERPRETATION

177Lu-PSMA-617 prolonged radiographic progression-free survival relative to ARPI change, with a favourable safety profile. For patients with PSMA-positive metastatic castration-resistant prostate cancer who are being considered for a change of ARPI after progression on a previous ARPI, 177Lu-PSMA-617 may be an effective treatment alternative.

FUNDING

Novartis.

Emerging frontiers in androgen receptor research for prostate Cancer: insights from the 2nd international androgen receptor Symposium

Continued exploration of the androgen receptor (AR) is crucial, as it plays pivotal roles in diverse diseases such as prostate cancer (PCa), serving as a significant therapeutic focus. Therefore, the Department of Urology Dresden hosted an international meeting for scientists and clinical oncologists to discuss the newest advances in AR research. The 2nd International Androgen Receptor Symposium was held in Dresden, Saxony, Germany, from 26-27.04.2024, organised by Dr. Holger H.H. Erb. Following the format of the first meeting, more than 35 scientists from 8 countries attended the event to discuss recent developments, research challenges, and identification of venues in AR research. An important new feature was the involvement of PhD students and young investigators, acknowledging the high scientific quality of their work. The symposium included three covers: new advances from clinical research, basic and translational research, and novel strategies to target AR. Moreover, based on its increasing clinical relevance, a PSMA theranostic mini-symposium was added at the end of the AR symposium to allow the audience to discuss the newest advances in PSMA theranostic. This report focuses on the highlights and discussions of the meeting.

Review on the Increasing Role for PSMA-Based Radioligand Therapy in Prostate Cancer

In 2021, two randomized controlled trials (RCTs), TheraP and VISION, demonstrated that 177Lu-PSMA-617 as monotherapy was more effective for the decline of PSA than the comparator third-line treatments.

METHODS

Our review summarizes new RCTs that add to the use of radioligand therapy (RLT) for patients with high-risk prostate cancer (PCa).

RESULTS

Four past and present RCTs included 1081 patients. An RCT, ENZA-p, studied first-line treatment of patients with metastatic castration-resistant PCa (mCRPC). A combination of enzalutamide (ENZA) and 177Lu-PSMA-617 gave longer progression-free survival than ENZA as monotherapy. Other RCTs of patients with mCRPC, including the PSMAfore, and SPLASH trials, showed 177Lu-PSMA-617 as second-line treatment gave better progression-free survival than androgen receptor pathway inhibitors (combined p value < 6.9 × 10-6).

CONCLUSIONS

Patients with PCa gain if they are given PSMA-RLT early in the treatment of PCa and as part of combination therapies.

Combination Strategies and Targeted Radionuclide Therapies

Combination models utilising treatments from two or more therapeutic classes are well established in cancer care. In the new era of theranostic (theragnostic) medicine there is an ongoing need to identify and refine novel combination strategies to optimise multidisciplinary care for conditions commonly encountered in nuclear medicine such as neuroendocrine neoplasms (NEN), prostate cancer (PCa), and thyroid cancer, along with seeking advancements in molecular imaging and therapy techniques for other tumour streams. This concise review explores the background of theranostic monotherapy, established approaches to combination strategies in theranostics, and emerging targeted radionuclide therapies in use or under active investigation, with a focus on Australian-led studies.

[68Ga]PSMA-11 for positron emission tomography (PET) imaging of prostate-specific membrane antigen (PSMA)-positive lesions in men with prostate cancer

INTRODUCTION

Theranostics targeting prostate-specific membrane antigen (PSMA) represent a new targeted approach for prostate cancer care that combines diagnostic and therapeutic radiopharmaceuticals to diagnose and treat the disease. Positron emission tomography (PET) is the imaging method of choice and several diagnostic radiopharmaceuticals for quantifying PSMA have received FDA approval and are in clinical use. [68Ga]Ga-PSMA-11 is one such imaging agent and the focus of this article. One beta-emitting radioligand therapy ([177Lu]Lu-PSMA-617) has also received FDA approval for prostate cancer treatment, and several other alpha- and beta-emitting radioligand therapies are in clinical trials.

AREAS COVERED

Theranostics targeting PSMA in men with prostate cancer are discussed with a focus on use of [68Ga]Ga-PSMA-11 for imaging PSMA-positive lesions in men with prostate cancer. The review covers [68Ga]Ga-PSMA-11 manufacture, current regulatory status, comparison of [68Ga]Ga-PSMA-11 to other imaging techniques, clinical updates, and emerging applications of artificial intelligence for [68Ga]Ga-PSMA-11 PET.

EXPERT OPINION

[68Ga]Ga-PSMA-11 is used in conjunction with a PET/CT scan to image PSMA positive lesions in men with prostate cancer. It is manufactured by chelating precursor with68Ga, either from a generator or cyclotron, and has regulatory approval around the world. It is widely used clinically in conjunction with radioligand therapies like [177Lu]Lu-PSMA-617.

From Despair to Hope: First Arabic Experience of 177Lu-PSMA and 161Tb-PSMA Therapy for Metastatic Castration-Resistant Prostate Cancer

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.

PARP inhibitors alone or in combination for prostate cancer

DNA repair genomic aberrations in the Homologous Recombination pathway are identifiable in up to 25% of patients with advanced prostate cancer, making them more likely to benefit from treatment with poly (ADP-ribose) polymerase inhibitors (PARPi) alone or in combination with other therapies, particularly when BRCA driver genomic aberrations are documented. Although several clinical trials have demonstrated the efficacy of this approach, the validation of reliable biomarkers predictive of response still needs further improvement to refine patient selection. In this setting, the characterization of resistance mechanisms and the validation of novel biomarkers are critical to maximize clinical benefit and to develop novel treatment combinations to improve outcomes. In this review, we summarize the development of PARPi in prostate cancer as single agent as well as the efficacy of their combination with other drugs, and the future directions for their implementation in the management of advanced prostate cancer.