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

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.

Expert Opinion on Current Treatment Alternatives for Patients With Prostate Cancer Progressing From the Metastatic Hormone-Sensitive Stage to the Castration-Resistant Stage After Receiving Early Treatment Intensification

For patients with castration-sensitive prostate cancer (mCSPC), treatment intensification with androgen deprivation therapy (ADT) plus new androgen receptor pathway inhibitors (ARPIs) has opened a scenario where no guidance exists to indicate the best treatment after progression to metastatic castration-resistant prostate cancer (mCRPC). Clinical decision-making has become even more complex, with the proven benefit for selected patients of triplet therapy with abiraterone or darolutamide added to the double combination therapy of ADT plus docetaxel. The profile of patients for whom triple therapy would be more beneficial is being defined beyond metastatic disease presentation and volume (eg, poor prognosis features). In October 2023 and October 2024, a panel of eight Spanish medical oncologists with expertise in the management of prostate cancer met to discuss the challenges in treating mCRPC. The scientific evidence was reviewed during this meeting, knowledge and experience were shared, and controversies were discussed until a consensus was reached. This information was collected and turned into a manuscript aimed at helping clinicians determine the optimal treatment sequence after disease progression based on scientific evidence and experts' opinions and consensus. To this end, the profile of mCSPC patients who may have received double or triplet therapy is analyzed, current treatment options are reviewed, and treatment algorithms are proposed. New and expected advancements in this field are also presented.

The role of radium-223 in the evolving treatment landscape of metastatic castration-resistant prostate cancer: A narrative review

The treatment of metastatic castration-resistant prostate cancer (mCRPC) has been rapidly evolving over the last two decades. The advent of new androgen receptor pathway inhibitors (ARPIs) such as abiraterone acetate or enzalutamide marks a great advance for treating mCRPC patientd in the pre- and post-docetaxel settings. The subsequent approval of ARPIs in early stages-i.e., metastatic hormone-sensitive (mHSPC) or nonmetastatic CRPC-led to a realignment of subsequent treatment choices upon progression to mCRPC, given the possibility of cross-resistance between ARPIs. Therapies with mechanisms of action different from those of ARPIs are now the focus of new treatment developments. Also, this anomalous situation brings the focus back to well-known treatments currently used later in the treatment sequence. This is the case of radium-223 which, when administered with enzalutamide, has recently been shown to prolong radiographic progression-free survival vs. enzalutamide alone in the first line in asymptomatic or mildly symptomatic patients with no known visceral metastases. In this narrative review, we summarize the treatment landscape for mCRPC, both from a historical and practical point of view, to understand the new potential of radium-223 as a treatment option in this setting.

Phase I, First-in-Human Study of FOR46 (FG-3246), an Immune-Modulating Antibody-Drug Conjugate Targeting CD46, in Patients With Metastatic Castration-Resistant Prostate Cancer

PURPOSE

FOR46, a fully human antibody conjugated to monomethyl auristatin E, targets a tumor-selective epitope of CD46, which is overexpressed in metastatic castration-resistant prostate cancer (mCRPC). FOR46 demonstrates potent nonclinical activity in enzalutamide-resistant CRPC models.

PATIENTS AND METHODS

This was a phase I, first-in-human, dose escalation/expansion study in patients with progressive mCRPC after treatment with ≥one androgen signaling inhibitors (ClinicalTrials.gov identifier: NCT03575819). The starting dose of FOR46 was 0.1 mg/kg given intravenously every 3 weeks. The primary objective was to determine the maximally tolerated dose (MTD). Whole-blood mass cytometry (cytometry by time of flight) was used to characterize peripheral immune response and CD46 expression in CRPC tissue that underwent central pathology review.

RESULTS

Fifty-six patients were enrolled. Dose-limiting toxicities included neutropenia (n = 4), febrile neutropenia (n = 1), and fatigue (n = 1). The MTD was 2.7 mg/kg using adjusted body weight. The most common grade ≥3 adverse events across all dose levels were neutropenia (59%), leukopenia (27%), lymphopenia (7%), anemia (7%), and fatigue (5%). One grade 3 febrile neutropenia event was observed. There were no treatment-related deaths. In the efficacy evaluable subset (patients with adenocarcinoma treated with a starting dose ≥1.2 mg/kg, n = 40), the median radiographic progression-free survival was 8.7 months (range, 0.1-33.9). Fourteen of 39 evaluable patients (36%) achieved a PSA50 response. The confirmed objective response rate was 20% (5 of 25 RECIST-evaluable patients). The median duration of response was 7.5 months. Responders had a significantly higher on-treatment frequency of circulating effector CD8+ T cells.

CONCLUSION

FOR46 demonstrated encouraging preliminary clinical activity with a manageable safety profile. Targeting CD46 elicited an immune priming effect that was associated with clinical outcomes.

Organ and tumour dosimetry of 177Lu-rhPSMA-10.1, a novel PSMA-targeted therapy: results from a Phase I trial

PURPOSE

To evaluate tumour and normal organ dosimetry of PSMA-targeted RLT 177Lu-rhPSMA-10.1.

METHODS

PSMA-positive mCRPC patients experiencing disease progression following standard-of-care treatment were enrolled and underwent ≤ 3 cycles of 5.55 or 7.40 GBq 177Lu-rhPSMA-10.1 at 6-week intervals. Multi-bed SPECT/CT was conducted 3-, 24-, 48-, and 168-hours post-administration to calculate tumour and organ absorbed doses. Two methods (activity- and anatomy-based) were used for selecting and delineating tumours for dosimetry. Venous blood was collected for radioactivity measurement 30 min before 177Lu-rhPSMA-10.1 administration, and 0.5-, 1.5-, 4-, 24-, and 48-hours post-administration.

RESULTS

Thirteen patients were enrolled; three received 5.55 GBq/cycle and 10 received 7.40 GBq/cycle. Mean absorbed doses were 0.266, 0.130 and 8.87 Gy/GBq in kidneys, salivary glands, and tumours (activity-method), respectively, giving mean tumour-to-kidney and tumour-to-salivary ratios of 32.1 and 73.2, respectively. Tumour dose estimates were consistently higher with the activity-method vs. anatomy-method. Tumour absorbed doses decreased each cycle; Cycle 2 and 3 doses were ~ 37% and ~ 56% lower than Cycle 1 estimates, respectively. 177Lu-rhPSMA-10.1 was rapidly cleared from the blood (effective half-life, 2.2 h). Imaging data showed mean effective half-lives to be 91.4, 33.7 and 45.4 h in tumours, kidneys, and salivary glands, respectively.

CONCLUSION

177Lu-rhPSMA-10.1 delivers high radiation doses to tumours vs. normal organs, facilitated by its favourable pharmacokinetics. Cumulative doses to normal organs were well within established tolerable limits, suggesting higher cumulative radioactivity could be administered in clinical trials. The observation of decreasing tumour absorbed dose with subsequent cycles also supports the exploration of front-loading radioactivity in Phase II.

Toxicities of radioligand and radioisotope therapy in prostate cancer: a systematic review and meta-analysis

PURPOSE OF REVIEW

This systematic review and meta-analysis investigate the toxicities of radioligand and radioisotope therapies - [177Lu]lutetium-prostate-specific membrane antigen (PSMA) (Lu-PSMA), [225Ac]actinium-PSMA (Ac-PSMA), and [223Ra]radium-dichloride (223-Radium) - in metastatic prostate cancer. While previous studies have explored this topic, most failed to differentiate between treatment-emergent adverse events (TEAEs) and preexisting conditions, leading to inflated toxicity rates. By focusing exclusively on TEAEs, this study provides a more accurate and clinically relevant assessment.

RECENT FINDINGS

This meta-analysis of 65 studies including 8706 patients identified haematotoxicities as the most frequent TEAEs across all therapies, affecting 10-20% of patients. Fatigue is a common nonhematologic adverse event in all treatments. Low grade xerostomia is specifically associated with Lu-PSMA and Ac-PSMA therapies, occurring in 30% and 84% of patients, respectively, while 223-Radium is uniquely linked to an increased fracture risk. Severe toxicities (Common Terminology Criteria for Adverse Events ≥ 3) are rare across all therapies. By clearly distinguishing TEAEs from baseline conditions, this study addresses a gap in the existing literature.

SUMMARY

Severe TEAEs are uncommon across Lu-PSMA, Ac-PSMA, and 223-Radium therapies. Still, monitoring and managing specific toxicities to optimize the safety and tolerability of these therapies in clinical practice is mandatory, especially concerning xerostomia in Ac-PSMA therapy.

Systemic Therapy in Patients With Metastatic Castration-Resistant Prostate Cancer: ASCO Guideline Update

PURPOSE

To provide evidence-based recommendations for patients with metastatic castration-resistant prostate cancer (mCRPC).

METHODS

An Expert Panel including patient representation completed a systematic review of the evidence and made recommendations.

RESULTS

Depending upon prior treatment received, androgen receptor pathway inhibitors (ARPIs: enzalutamide, abiraterone with prednisone), poly(ADP-ribose) polymerase inhibitors (PARPi), chemotherapeutic agents (docetaxel, cabazitaxel), radiopharmaceuticals (radium 223, 177Lu-prostate-specific membrane antigen [PSMA]-617), and sipuleucel-T have demonstrated an overall survival (OS) benefit for patients with mCRPC. For patients with BRCA1/2 alterations who did not receive prior ARPI, the combination of PARPi and ARPI (talazoparib + enzalutamide, olaparib and/or niraparib + abiraterone) has shown clinical benefit. For patients with BRCA1/2 alterations who received prior ARPI or ARPI followed by docetaxel, olaparib showed OS benefit. In select patients with microsatellite instability-high/mismatch repair-deficient, pembrolizumab showed clinical efficacy.

RECOMMENDATIONS

Prior systemic therapy for castration-sensitive prostate cancer will determine subsequent therapy used for mCRPC. Continue androgen-deprivation therapy for patients with mCRPC indefinitely. Early adoption of somatic genetic testing and palliative care is recommended. Patients with mCRPC and bony metastases should receive a bone-protective agent. The panel recommends the combination of ARPI with PARPi in patients with BRCA1/2 alterations who did not receive prior ARPI. For patients who received prior ARPI, the panel recommends docetaxel chemotherapy. The panel recommends 177Lu-PSMA-617 or cabazitaxel chemotherapy for patients who receive prior ARPI and docetaxel chemotherapy. For patients with BRCA1/2 alterations who received prior ARPI, the panel recommends PARPi monotherapy. Radium 223 is recommended for patients with symptomatic bone-only disease. Evidence for optimal sequencing for mCRPC regimens is lacking.Additional information is available at www.asco.org/genitourinary-cancer-guidelines.

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.

Treatment Landscape of Prostate Cancer in the Era of PSMA Radiopharmaceutical Therapy

The treatment landscape of prostate cancer is quite complex because of the many therapeutic options available in different disease settings (hormonal treatments, chemotherapy, poly(adenosine diphosphate ribose) polymerase inhibitors, radiopharmaceutical therapy). Since in most cases we do not have comparative studies between these different agents, the best therapeutic sequence in patients with prostate cancer remains unsolved. In this review, we describe the different systemic therapeutic options available in each disease setting from localized disease to metastatic castration-resistant disease. We also indicate when to use each of these therapeutic options in the therapeutic sequence on the basis of the results of the available studies. A special focus of this review is the place of prostate-specific membrane antigen radiopharmaceutical therapy in the treatment algorithms.

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.

Dose-Dense Docetaxel and Radium-223 in Bone-Dominant Metastatic Castration-Resistant Prostate Cancer

BACKGROUND

Disease progression in castration-resistant prostate cancer (CRPC) remains bone-dominant and docetaxel-responsive. Docetaxel and radium-223 would be a logical combination but myelosuppression is dose-limiting. Dose-dense schedules of docetaxel have comparable activity to bolus dosing with mitigated myelosuppression. We hypothesized that dose-dense docetaxel with standard radium-223 would be a feasible, safe and effective combination in bone-dominant metastatic CRPC.

METHODS

Subjects had progressive bone-predominant CRPC. Design was dose escalation plus expansion with 28-day cycles. Docetaxel was given every 2 weeks in a 4-week lead-in, then with Radium-223 every 4 weeks up to 6 cycles. Dose-levels (DL) included 1: docetaxel 40 mg/m2; 1a: docetaxel 40 mg/m2 with G-CSF on Day 16, 2a: docetaxel 50 mg/m2 with G-CSF on Day 16. The maximum tolerated dose (MTD) was defined as the highest (DL) of docetaxel achieved without dose-limiting toxicity (DLT). Markers of safety and efficacy were annotated.

RESULTS

Forty-three subjects were enrolled (NCT03737370). The patient population included 21% black, 9% Asians, 93% had prior intensified hormonal therapy, 67% had bone pain, and 76% had ≥ 4 bone metastases. Seven patients dropped out during the 4-week docetaxel lead in. Neutropenia at DL 1 limited combination therapy. No (DLT) occurred at DL 1a (n = 6) or DL 2a (n = 5). Twenty-two patients were enrolled to an expansion cohort with docetaxel 50 mg/m2 with G-CSF on Day 16 (DL 2a), the designated MTD. Among 35 patients treated with the combination, there were no febrile neutropenia events. One patient had dose-limiting Grade 3 anemia. PSA50 response was 51.4% and PSA90 was 25.7%. Median progression-free survival was 11.7 months, and median overall survival was 20.1 months.

CONCLUSIONS

A lead-in cycle and a dose-dense schedule of docetaxel with G-CSF enabled the combination with radium-223 in standard dose-intensities with minimal hematological toxicity. The regimen will likely combine logically and safely with hormone-intensification for study in high-risk/high-volume castration-sensitive metastatic disease.

Advances in Targeted Therapy for Metastatic Prostate Cancer

OPINION STATEMENT

Over the past few years, treatment for advanced prostate cancer has begun shifting away from a one-size-fits-all approach toward biomarker-based therapies for select groups of patients. This review highlights the role of poly-ADP-ribose-polymerase (PARP) inhibitors in metastatic prostate cancer, emerging strategies to target the androgen receptor (AR), and innovative therapies aimed at cell surface proteins, including radioligand therapies, bispecific T cell engagers, and antibody-drug conjugates. For patients with homologous recombination repair (HRR)-mutated metastatic castration-resistant prostate cancer (CRPC), we favor combining a PARP inhibitor (PARPi) with an AR pathway inhibitor (ARPI), provided they can tolerate a more aggressive treatment strategy. In our opinion, patients with BRCA1 or BRCA2 mutations who are unable to handle combination therapy benefit from PARPi monotherapy. We are enthusiastic about the potential of ongoing clinical trials for new AR-directed therapies, such as AR ligand-directed degraders and CYP11A1 inhibitors, in metastatic CRPC. These treatments are expected to be most beneficial for patients whose cancer continues to rely on AR pathway signaling, suggesting they might also be effective in earlier stages of the disease. Progress in drug development and understanding of protein structures has led to new therapies that target cell surface proteins predominantly found in prostate cancer. We use 177Lu-PSMA-617 for patients with PSMA avid metastatic CRPC who have progressed on an ARPI and a taxane chemotherapy. Additionally, we see promising potential in bispecific T-cell engagers (e.g., STEAP1-CD3 and PSMA-CD3) and novel radioligand therapies, including those utilizing actinium, to target these proteins. These advances show great promise in further enhancing survival for patients with metastatic prostate cancer.

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.

Targeting the tumour cell surface in advanced prostate cancer

Prostate cancer remains a substantial health challenge, with >375,000 annual deaths amongst men worldwide. Most prostate cancer-related deaths are attributable to the development of resistance to standard-of-care treatments. Characterization of the diverse and complex surfaceome of treatment-resistant prostate cancer, combined with advances in drug development that leverage cell-surface proteins to enhance drug delivery or activate the immune system, have provided novel therapeutic opportunities to target advanced prostate cancer. The prostate cancer surfaceome, including proteins such as prostate-specific membrane antigen (PSMA), B7-H3, six transmembrane epithelial antigen of the prostate 1 (STEAP1), delta-like ligand 3 (DLL3), trophoblastic cell-surface antigen 2 (TROP2), prostate stem cell antigen (PSCA), HER3, CD46 and CD36, can be exploited as therapeutic targets, as regulatory mechanisms might contribute to the heterogeneity of expression of these proteins and subsequently affect treatment response and resistance. Specific treatment strategies targeting the surfaceome are in clinical development, including radionuclides, antibody-drug conjugates, T cell engagers and chimeric antigen receptor (CAR) T cells. Ultimately, biomarker development and clinical implementation of these agents will be informed and refined by further understanding of the biology of various targets; the target specificity and sensitivity of different agents; and off-target and toxic effects associated with these agents. Understanding the dynamic nature of cell-surface targets and non-overlapping expression patterns might also lead to future combinational strategies.

Baseline Imaging Derived Factors of Response Following [225Ac]Ac-J591 Therapy in Metastatic Castration-Resistant Prostate Cancer: A Lesion Level Analysis

PURPOSE

Actinium-225 labeled prostate-specific membrane antigen (PSMA) targeted radionuclide therapy has emerged as a potential treatment option in the management of men with metastatic castrate-resistant prostate cancer (mCRPC). This study investigated molecular imaging-derived parameters and compared imaging response of lesions categorized by tumor site.

METHODS

Men with mCRPC treated with [225Ac]Ac-J591 from 2017 to 2022 at our center on two prospective trials (NCT03276572 and NCT04506567) with pre- and post-treatment [68Ga]Ga-PSMA-11 Positron Emission Tomography (PET) imaging studies available were included. SUVpeak of the 3 most- and 3 least-avid lesions of the tumor sites were manually assessed. The median change of the SUVpeak from pre- to post-treatment per tumor site was evaluated using the paired Wilcox test. An objective response (OR) in the follow-up image was defined as complete or partial response using PET Response Criteria in Solid Tumors (PERCIST) 1.0.

RESULTS

A total of 46 cases met the criteria for image review; most of them (n = 25, 54.3%) had more than one tumor site category. In total, 445 PSMA PET-positive lesions were assessed: 220 osseous, 163 nodal, 41 visceral, and 21 prostatic lesions. After treatment with [225Ac]Ac-J591, absolute SUVpeak values per tumor site declined significantly (p < 0.05) except for prostatic lesions (p = 1). The PERCIST-OR rate for osseous, nodal, visceral, and prostatic lesions was 53%, 28%, 56%, and 38%, respectively.

CONCLUSION

[225Ac]Ac-J591 is an active treatment in men with mCRPC. Tumor distribution patterns may influence treatment response and potentially prognosis. Our findings warrant further validation in a larger cohort but may be considered in treatment planning and trial design.

Platelets, Chromogranin A, and C-Reactive Protein Predict Therapy Failure of Metastatic Hormone-Sensitive Prostate Cancer while miR-375 Outperforms Prostate-Specific Antigen in Stratifying Castration-Resistant Prostate Cancer

Androgen deprivation therapy has long been the first-line treatment for hormone-sensitive prostate cancer (HSPC). After progression to castration-resistant prostate cancer (CRPC), androgen receptor pathway inhibitors (ARPIs) are commonly used. Recently, combined therapy with androgen deprivation and an ARPI has been recommended for metastatic HSPC patients. Novel markers are urgently needed for monitoring this disease and for making therapeutic decisions. Plasma samples were collected from 140 patients with either metastatic HSPC (n = 72) or CRPC (n = 68) before the start of ARPI therapy. Digital PCR was used to assess AR gene amplification, while the expression levels of miR-375 were measured by quantitative PCR. Sixteen other clinical markers were also evaluated, including prostate-specific antigen (PSA), chromogranin A (CGA), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), C-reactive protein (CRP), lymphocyte-to-monocyte ratio, and platelet count. A multivariate analysis, adjusted for age and metastatic dissemination, identified miR-375 expression and lymphocyte-to-monocyte ratio to be the independent negative predictors of ARPI therapy failure in CRPC patients. Regarding the HSPC patients, this article reports the primary finding of the independent negative predictive value of platelet count, CRP, and CGA for the failure of combined androgen deprivation therapy and ARPI.

[Radionuclide therapy in 2025: nuclear medicine options in the treatment of metastatic castration-resistant prostate cancer]

BACKGROUND

Radionuclide therapy continues to gain in importance thanks to promising clinical results. It is a suitable treatment option for many patients and is increasingly establishing itself as a key pillar in the treatment of metastatic castration-resistant prostate cancer (mCRPC).

OBJECTIVE

This article summarizes the current role of radionuclide therapies in the treatment of mCRPC and provides insights into recent developments.

METHODS

Presentation of key study results, current approval labels and ongoing clinical trials.

RESULTS

Significant prolongation of survival through treatment with lutetium-177-PSMA-617 and radium-223-dichloride has led to approval of both substances in late-stage mCRPC. Further study results on the effectiveness of lutetium-PSMA in earlier stages and on the use of the alpha emitter actinium-225 are expected.

Radiotherapeutics, clonal hematopoiesis, and risk of hematologic malignancies: The good, the bad, the ugly

While radiotherapeutics have demonstrated significant clinical benefit across multiple cancer types including thyroid cancer, neuroendocrine tumors, and prostate cancer, hematological toxicities can be frequent and challenging. It remains unknown to what extent the hematologic toxicity is driven by clonal processes that preexist and are selected for by treatment induced selection pressures. In this review, we discuss the background leading to the adoption of radiotherapeutics in the treatment of solid tumor malignancies, the risk of hematologic toxicities and myeloid neoplasms and the evidence pointing to potential precursor lesions that may predispose patients to hematologic toxicities. Additionally, we discuss how prevalent clonal hematopoiesis is among patients with solid tumor malignancies and suggest workflows for patients with cytopenias or clonal hematopoiesis who are receiving or have received radiotherapeutic agents.

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.

Trends in the research and development of peptide drug conjugates: artificial intelligence aided design

Peptide-drug conjugates (PDCs) represent an emerging class of targeted therapeutic agents that consist of small molecular drugs coupled to multifunctional peptides through cleavable or non-cleavable linkers. The principal advantage of PDCs lies in their capacity to deliver drugs to diseased tissues at increased local concentrations, thereby reducing toxicity and mitigating adverse effects by limiting damage to non-diseased tissues. Despite the increasing number of PDCs being developed for various diseases, their advancements remain relatively slow due to several development constraints, which include limited available peptides and linkers, narrow therapeutic applications, and incomplete evaluation and information platforms for PDCs. Marked by the recent Nobel Prize awarded to artificial intelligence (AI) and de novo protein design for "protein design and structure prediction," AI is playing an increasingly important role in drug discovery and development. In this review, we summarize the recent developments and limitations of PDCs, highlights the potential of AI in revolutionizing the design and evaluation of PDC.

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.

Clinical advances and practice updates in genitourinary cancers: a 2024 review from the multidisciplinary Spanish 'Cambados annual meeting'

Prostate, bladder and kidney neoplasms are among the most prevalent genitourinary (GU) cancers worldwide. Significant therapeutic advancements in recent years have substantially improved patient outcomes. In response to this rapid progress, the Santiago de Compostela Health Research Institute (IDIS) has organized the annual 'Cambados Consensus Forum on Genitourinary Tumors' (Pontevedra, Spain) since 2018. This 2-day multidisciplinary meeting gathers Spanish medical oncologists, radiation oncologists, urologists, and hospital pharmacists to present and discuss the latest evidence in the field, merging from international congresses or journal publications. This review provides an overview of the most recent evidence regarding therapeutic advances in prostate cancer, renal cell carcinoma, and bladder cancer presented at the 2024 meeting (October), with a special focus on practice-changing innovations.

Postmarketing safety of [177Lu]Lu-PSMA-617 radioligand therapy for prostate cancer: a disproportionality analysis of the FDA adverse event reporting system

BACKGROUND

[177Lu]Lu-PSMA-617 (Pluvicto), a new radioligand therapy that targets prostate-specific membrane antigen (PSMA), has been approved to treat metastatic castration-resistant prostate cancer (mCRPC). However, the real-world safety profile of [177Lu]Lu-PSMA-617 has not been systemically evaluated.

RESEARCH DESIGN AND METHODS

Adverse event reports for [177Lu]Lu-PSMA-617 were retrieved from April 2022 to June 2024 from The Food and Drug Administration Adverse Event Reporting System (FAERS) database. Disproportionality analysis was conducted by four algorithms: reporting odds ratio (ROR), proportional reporting ratio (PRR), Multi-Item Gamma Poisson Shrinker (MGPS) and Bayesian Confidence Propagation Neural Network (BCPNN). Subgroup analysis, time-to-onset and sensitivity analysis were also employed.

RESULTS

384,2712 adverse event reports were retrieved, of which 870 were associated with [177Lu]Lu-PSMA-617 in prostate cancer patients. We identified known adverse events (fatigue/asthenia, anemia, thrombocytopenia and nausea) and discovered adverse events not specified on the label (loss of libido, hydronephrosis, supraventricular tachycardia, tumor lysis syndrome, and tumor flare). Subgroup analysis revealed high-risk signals included stomatitis, pneumonia, leukopenia, and sepsis for patients aged over 85. The median onset time was 55 days (interquartile range 24-124 days).

CONCLUSIONS

The findings provide new insights into the adverse events of [177Lu]Lu-PSMA-617 and valuable references for clinical applications of radioligand therapy for mCRPC.

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.

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.

Management of Dry Mouth Toxicity Following 177Lu-PSMA-617 Radioligand Therapy

Treatment options for patients with metastatic castration-resistant prostate cancer include the use of radioligand therapy with 177Lu-PSMA-617. Although 177Lu-PSMA-617 can selectively target prostate cancer cells, salivary glands express PSMA on the apical lumen of the acinar epithelium. Xerostomia resulting from the use of radioligand therapy is common. Herein, we report on a case of a Common Terminology Criteria for Adverse Events version 5 grade 2 dry mouth event after administration of 177Lu-PSMA-617. The patient was managed with oral hygiene and xerostomia mitigation strategies using oral rinses.

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.

Advanced Imaging for Localized Prostate Cancer

BACKGROUND/OBJECTIVES

Prostate cancer is a prevalent malignancy often presenting without early symptoms. Advanced imaging technologies have revolutionized its diagnosis and management. This review discusses the principles, benefits, and clinical applications of multiparametric magnetic resonance imaging (mpMRI), micro-ultrasound (microUS), and prostate-specific membrane antigen positron emission tomography-computed tomography (PSMA PET/CT) in localized prostate cancer.

METHODS

We conducted a comprehensive literature review of recent studies and guidelines on mpMRI, microUS, and PSMA PET/CT in prostate cancer diagnosis, focusing on their applications in biopsy-naïve patients, those with previous negative biopsies, and patients under active surveillance.

RESULTS

MpMRI has demonstrated high sensitivity and negative predictive value in detecting clinically significant prostate cancer (csPCa). MicroUS, a newer technology, has shown promising results in early studies, with sensitivity and specificity comparable to mpMRI. PSMA PET/CT has emerged as a highly sensitive and specific imaging modality, particularly valuable for staging and detecting metastatic disease. All three technologies have been incorporated into urologic practice for prostate cancer diagnosis and management, with each offering unique advantages in different clinical scenarios.

CONCLUSIONS

Advanced imaging techniques, including mpMRI, microUS, and PSMA PET/CT, have significantly improved the accuracy of prostate cancer diagnosis, staging, and management. These technologies enable more precise targeting of suspicious lesions during biopsy and therapy planning. However, further research, especially randomized controlled trials, is needed to fully establish the optimal use and inclusion of these imaging modalities in various stages of prostate cancer care.