Biomarkers in metastatic castration-resistant prostate cancer for efficiency of immune checkpoint inhibitors

Almost all patients with prostate cancer progress to metastatic castration-resistant prostate cancer (mCRPC) despite initial responses. In cases where traditional first-line treatments prove ineffective, the potential of immune checkpoint blockade (ICB) therapy emerges as a promising approach for managing mCRPC. However, while immune checkpoint inhibitor monotherapy or combination therapy targeting cytotoxic T lymphocyte antigen 4 (CTLA-4) and/or programmed cell death-1 (PD-1)/PD-1 ligand 1 (PD-L1) axis has been regarded as the standard therapy in many solid tumours, mCRPC as 'cold' tumours are considered to be relatively resistant to ICB treatment. Encouragingly, recent evidence suggests that ICB therapy may be particularly beneficial in specific subgroups of patients with high PD-L1 tumour expression, high tumour mutational burden or high tumour microsatellite instability/mismatch repair deficiency. Better understanding of these predictive biomarkers could screen which patients are most likely to benefit. This review article examines biomarkers for screening patients potentially effective in immune checkpoint inhibitor therapy.

Peptides-functionalized gold nanostars enhanced degradation of PD-L1 for improved prostate cancer immunotherapy

Blockage of the interaction between programmed death receptor-1 (PD-1) and programmed death ligand-1 (PD-L1) can restore T-cell activity and enhance antitumor immunity. PD-1/PD-L1 pathway inhibitors have promising applications in the treatment of advanced prostate cancer (PCa). We successfully developed a peptides-functionalized gold nanoconstruct (P-AuNS) consisted of PD-L1-binding peptide (PD-L1pep, P) and gold nanostar (AuNS), which could bind to cell-surface PD-L1 specifically and deliver PD-L1 into PCa cells with high efficiency. In PCa cells, P-AuNS can efficiently degrade PD-L1 in a lysosomal-dependent manner. In the co-culture system of Jurkat cells and DU145 cells, P-AuNS restored the proliferative capacity and interferon-gamma (IFN-γ) secretion level of Jurkat cells inhibited by co-cultured DU145 cells, indicating that P-AuNS effectively hampered the interaction between PD-1 and PD-L1. In addition, in PCa-bearing mice, P-AuNS can effectively inhibit tumor growth and down-regulate PD-L1 protein levels, and in vivo experimental results show that P-AuNS has no systemic toxicity. P-AuNS block the interaction between PD-1 and PD-L1 by efficiently degrading PD-L1, thus restoring the antitumor activity of T cells and inhibiting tumor progression of PCa. In all, P-AuNS has great promise as a potential immunotherapy strategy in the treatment of advanced PCa and even other solid tumors.

Synergistic effects of immunotherapy and adjunctive therapies in prostate cancer management

In recent years, cancer immunotherapy has received widespread attention due to significant tumor clearance in some malignancies. Various immunotherapy approaches, including vaccines, immune checkpoint inhibitors, oncolytic virotherapy, bispecific T cell engagers, and adoptive T cell transfer, have completed or are undergoing clinical trials for prostate cancer. Despite immune checkpoint blockade's extraordinary effectiveness in treating a variety of cancers, targeted prostate cancer treatment using the immune system is still in its infancy. Multiple factors including the heterogeneity of prostate cancer, the cold tumor microenvironment, and a low level of neoantigens, contribute to the poor immunotherapy response. Significant effort is being devoted to improving immune-based prostate cancer therapy. Recently, several key discoveries demonstrate that prostate cancer immunotherapy agents may be used to promise better prognosis for patients as part of combination strategies with other agents targeting tumor-associated immune mechanism of resistance. Here, this review comprehensively examines the recent advancements in immunotherapy for prostate cancer, exploring its potential synergistic effects when combined with other treatment modalities to enhance clinical efficacy.

Interactions and communications in the prostate tumour microenvironment: evolving towards effective cancer therapy

Prostate cancer is one of the most common malignancies in men. The tumour microenvironment (TME) has a critical role in the initiation, progression, and metastasis of prostate cancer. TME contains various cell types, including cancer-associated fibroblasts (CAFs), endothelial cells, immune cells such as macrophages, lymphocytes B and T, natural killer (NK) cells, and other proteins such as extracellular matrix (ECM) components. The interactions and communications between these cells within the TME are crucial for the growth and response of various solid tumours, such as prostate cancer to different anticancer modalities. In this review article, we exemplify the various mechanisms by which the TME influences prostate cancer progression. The roles of different cells, cytokines, chemokines, and growth factors in modulating the immune response and prostate tumour growth will be discussed. The impact of these cells and factors and other ECM components on tumour cell invasion and metastasis will also be discussed. We explain how these interactions in TME can affect the response of prostate cancer to therapy. We also highlight the importance of understanding these interactions to develop novel therapeutic approaches for prostate cancer.

Natural Killer Cell Infiltration in Prostate Cancers Predict Improved Patient Outcomes

BACKGROUND

Natural killer (NK) cells are non-antigen specific innate immune cells that can be redirected to targets of interest using multiple strategies, although none are currently FDA-approved. We sought to evaluate NK cell infiltration into tumors to develop an improved understanding of which histologies may be most amenable to NK cell-based therapies currently in the developmental pipeline.

METHODS

DNA (targeted/whole-exome) and RNA (whole-transcriptome) sequencing was performed from tumors from 45 cancer types (N = 90,916 for all cancers and N = 3365 for prostate cancer) submitted to Caris Life Sciences. NK cell fractions and immune deconvolution were inferred from RNA-seq data using quanTIseq. Real-world overall survival (OS) and treatment status was determined and Kaplan-Meier estimates were calculated. Statistical significance was determined using X2 and Mann-Whitney U tests, with corrections for multiple comparisons where appropriate.

RESULTS

In both a pan-tumor and prostate cancer (PCa) -specific setting, we demonstrated that NK cells represent a substantial proportion of the total cellular infiltrate (median range 2-9% for all tumors). Higher NK cell infiltration was associated with improved OS in 28 of 45 cancer types, including (PCa). NK cell infiltration was negatively correlated with common driver mutations and androgen receptor variants (AR-V7) in primary prostate biopsies, while positively correlated with negative immune regulators. Higher levels of NK cell infiltration were associated with patterns consistent with a compensatory anti-inflammatory response.

CONCLUSIONS

Using the largest available dataset to date, we demonstrated that NK cells infiltrate a broad range of tumors, including both primary and metastatic PCa. NK cell infiltration is associated with improved PCa patient outcomes. This study demonstrates that NK cells are capable of trafficking to both primary and metastatic PCa and are a viable option for immunotherapy approaches moving forward. Future development of strategies to enhance tumor-infiltrating NK cell-mediated cytolytic activity and activation while limiting inhibitory pathways will be key.

A real-world experience of pembrolizumab monotherapy in microsatellite instability-high and/or tumor mutation burden-high metastatic castration-resistant prostate cancer: outcome analysis

BACKGROUND

The efficacy of pembrolizumab monotherapy in metastatic castration-resistant prostate cancer patients (mCRPC) when stratified by MSI-H and/or TMB-H is poorly defined. Additionally, outcomes based on sequencing source (i.e., tissue or liquid biopsy) have not been well described. We sought to assess outcomes of pembrolizumab monotherapy in patients with mCRPC and compare efficacy based on MSI-H and/or TMB-H when identified by tissue or liquid biopsy.

METHODS

A retrospective analysis was performed of mCRPC patients treated at Mayo Clinic with pembrolizumab monotherapy between 2018 and 2023. Objective response rates (ORR), median progression-free survival (mPFS), and overall survival (mOS), were determined by RECIST v1.1 criteria.

RESULTS

Twenty-two patients with mCRPC received pembrolizumab monotherapy for at least 3 cycles for a MSI-H or TMB-H indication. All patients had next generation sequencing (NGS) performed via tissue (n = 11) or liquid (n = 10) biopsy source. The ORR was 50% (27.3% complete response and 22.7% had partial response). The mPFS for TMB 10-14.9 mut/Mb (n = 4), TMB 15-24.9 mut/Mb (n = 6), and TMB ≥ 25 mut/Mb (n = 10) was 2.1, not reached (NR), and NR, respectively (p = 0.0003). The mOS for these same groups was 5.1 months, 20.5 months, and not reached, respectively. Among patients with TMB-H without co-occurring MSI-H or CDK12 (n = 6), none experienced a response and only one patient had stable disease compared to patients with MSI-H (n = 12) for whom the ORR was 75%. Immunotherapy responsive alterations such as ATRX and PTCH1 mutations were frequently noticed among patients who had complete response (CR).

CONCLUSIONS

Our hypothesis-generating study suggests that MSI-H drives the efficacy of pembrolizumab in mCRPC with better survival outcomes as TMB increases. Clinicians should consider alternative treatment strategies for advanced prostate cancer when TMB-H is present without co-occurring MSI-H or CDK12.

Overcoming drug resistance in castrate-resistant prostate cancer: current mechanisms and emerging therapeutic approaches

Metastatic castration-resistant prostate cancer (mCRPC) is driven by a complex network of resistance mechanisms against standard-of-care therapies, resulting in poor long-term outcomes. This review offers a uniquely comprehensive and integrative perspective on these resistance pathways, systematically examining both androgen receptor (AR)-dependent factors (including AR overexpression, point mutations, glucocorticoid receptor signaling, splice variants, post-translational modifications, altered coregulators, and intratumoral hormone biosynthesis) and AR-independent pathways (such as neuroendocrine differentiation, lineage plasticity, and alternative growth factor signaling). We also highlight resistance mechanisms influencing immunotherapy, chemotherapy, radiopharmaceutical therapy and targeted therapy. By synthesizing emerging insights across these domains, this review not only clarifies the underlying biology of mCRPC resistance but also identifies key leverage points for more effective interventions. Building on this foundation, we propose a forward-looking framework for overcoming mCRPC drug resistance, emphasizing the importance of biomarker-guided patient selection, combination strategies that simultaneously target multiple resistance mechanisms, and novel therapies under investigation. These recommendations are intended to guide future clinical trial designs and research priorities that move beyond incremental improvements. Ultimately, this comprehensive synthesis aims to serve as a resource for clinicians and researchers to accelerate the development of durable, precision-based treatment strategies in mCRPC.

Prostate Cancer: A Journey Through Its History and Recent Developments

Prostate cancer is one of the most common diseases among men worldwide and continues to pose a serious threat to health. This review shows the history and the new developments in the management of prostate cancer, with an emphasis on a range of therapeutic approaches, such as hormone therapy, radiation therapy, surgery, and innovative targeted therapeutics. The evolution of these treatments is examined in light of clinical outcomes, patient quality of life, and emerging resistance mechanisms, such as the recently shown vitamin D-based strategies. New developments that have the potential to increase survival rates and reduce side effects are also discussed, including PARP inhibitors (PARPis), immunotherapy, and tailored medication. Additionally, the use of biomarkers and sophisticated imaging methods in therapeutic decision-making is explored, with a focus on how these tools might improve patient care. The absolute necessity for a multidisciplinary approach for improving treatment strategies is becoming more and more apparent as our understanding of the biology of prostate cancer deepens. This approach ensures that patients receive customized medicines that fit their unique profiles. Future avenues of investigation will focus on resolving issues dealing with treatment efficacy and resistance to improve treatment results, ultimately leading to disease cure for prostate cancer patients.

Interleukin expression patterns and immune cell infiltration in prostate adenocarcinoma: Implications for recurrence risk

OBJECTIVE

This study aims to comprehensively investigate the expression profiles of interleukins in prostate adenocarcinoma (PRAD) and their relationship with immune cell infiltration, tumor progression, and patient prognosis. By establishing an interleukin-related risk score, we seek to enhance the understanding of the tumor immune microenvironment and facilitate the development of tailored immunotherapeutic strategies for PRAD patients.

INTRODUCTION

Interleukins can nurture a tumor promoting environment and simultaneously regulate immune cell infiltration. However, the potential roles of interleukins in the prostate adenocarcinoma immune landscape remain abstruse.

METHODS

We comprehensively investigated the interleukin expression patterns and tumor immune landscape of prostate adenocarcinoma patients. And explored the interleukin expression patterns with immune infiltration landscape. The interleukin score was established using LASSO cox regression analysis. Multivariate Cox regression analysis was employed to assess the prognostic value of the interleukin score.

RESULTS

We identified two distinct interleukin clusters, characterized by different immune cell infiltration, tumor promoting signaling pathways activation and prognosis. The interleukin score was established to estimate the prognosis of individual prostate adenocarcinoma (PRAD) patient. Further analysis demonstrated that the interleukin score was an independent prognostic factor of PRAD. Finally, we investigated the predictive value of interleukin score in the programmed cell death protein (PD-1) blockade therapy of patients with prostate adenocarcinoma. At the same time, the differences in related genes among different prostate cell lines were also identified.

CONCLUSIONS

This study demonstrated the correlation between interleukin and tumor immune landscape in prostate adenocarcinoma. The comprehensive evaluation of interleukin expression patterns in individual prostate patients contribute to our understanding of the immune landscape and helps clinicians selecting proper immunotherapy strategies for prostate patients.

Oral Cyclophosphamide for Patients With Metastatic Castration-Resistant Prostate Cancer in a Scenario of Limited Health Care Resources

PURPOSE

Prior noncontemporary studies showed that oral cyclophosphamide is an active treatment of metastatic castration-resistant prostate cancer (mCRPC). However, cyclophosphamide is currently underutilized in routine clinical practice given the lack of survival benefit and the emergence of more effective treatments.

METHODS

We retrospectively reviewed our institutional database to identify patients with mCRPC treated with cyclophosphamide. Prostate-specific antigen decrease ≥50% from baseline (PSA50) response was determined as the proportion of patients achieving a prostate-specific antigen (PSA) decline ≥50% from baseline. Radiographic responses and progression were evaluated by Prostate Cancer Working Group 3. Survival estimates used the Kaplan-Meier method, and correlations were made with Chi-square test for categorical variables.

RESULTS

From January 2011 to January 2023, 341 patients with mCRPC received oral cyclophosphamide at a tertiary cancer center in São Paulo, Brazil. The most common regimen (95%) was 100 mg once daily 21 days on, 7 days off. At prostate cancer diagnosis, the median age was 64.4 years (IQR, 59.4-70.8), 61.9% had metastatic de novo disease, and 55.5% had Gleason ≥8. The median number of previous treatment lines was three (IQR, 2-4). Any PSA decline was observed in 33.4%, and 13.2% had a PSA50 response. Median response duration was 2.1 months (IQR, 1.4-3.8). Ten patients (3%) were treated for ≥1 year. PSA50 response was associated with no prior docetaxel use and Eastern Cooperative Oncology Group performance status 0 or 1.

CONCLUSION

Oral cyclophosphamide is a feasible treatment option for patients with mCRPC, particularly in a scenario of limited health care resources.

Filamentous phages as tumour-targeting immunotherapeutic bionanofibres

Programmed cell death-ligand 1 (PD-L1) blockers have advanced immunotherapy, but their lack of tumour homing capability represents a substantial challenge. Here we show that genetically engineered filamentous phages can be used as tumour-targeting immunotherapeutic agents that reduce the side effects caused by untargeted delivery of PD-L1 blockers. Specifically, we improved biopanning to discover a peptide binding the extracellular domain of PD-L1 and another targeting both melanoma tissues and cancer cells. The two peptides were genetically fused to the sidewall protein and tip protein of fd phages, respectively. The intravenously injected phages homed to tumours and bound PD-L1 on cancer cells, effectively blocking PD-1/PD-L1 recognition to trigger targeted immunotherapy without body weight loss, organ abnormalities and haematological aberrations. The phages, cost-effectively replicated by bacteria, are cancer-targeting immunotherapeutic nanofibres that can be flexibly designed to target different cancer types and immune checkpoints.

Implementation of Universal Germline Genetic Testing Into Standard of Care for Patients With Prostate Cancer: The Time Is Now

Indications for and implications of germline genetic testing (GGT) in patients with prostate cancer have expanded over the past decade, particularly related to precision therapies and management. GGT has become the standard of care for many cancers such as breast, ovarian, colorectal, pancreatic, and metastatic prostate cancer, and it is imperative that patients be offered timely and equitable access to testing as it can inform patient-physician shared decision making for management of the current cancer as well as anticipatory guidance for disease progression. Additionally, GGT guides screening for and prevention of secondary malignancies for the patient and cascade testing for at-risk family members. Here, we present data supporting the notion that clinicians should offer all patients with prostate cancer the opportunity to undergo comprehensive GGT for pathogenic germline variants known to be associated with familial cancer and/or known to have implications for treatment and management.

Recent and Future Developments in the Use of Poly (ADP-ribose) Polymerase Inhibitors for Prostate Cancer

BACKGROUND AND OBJECTIVE

Advanced prostate cancer (PCa) is enriched for alterations in DNA damage repair genes; poly (ADP-ribose) polymerase (PARP) inhibitors (PARPi) are a class of drugs that have demonstrated effectiveness in PCa, particularly in tumors with alterations in BRCA1/2 and other homologous recombination repair (HRR) genes, acting through a synthetic lethal mechanism. To prevent or delay drug resistance, and to expand the patient population that can benefit from this class of drug, combination treatment strategies have been developed in preclinical and clinical studies.

METHODS

This review examines the latest developments in clinical trials testing PARPi for advanced PCa and their emerging role in earlier disease settings. Furthermore, it discusses the critical role of careful patient selection and identification of additional biomarkers to enhance treatment efficacy.

KEY FINDINGS AND LIMITATIONS

Two PARPi (olaparib and rucaparib) have been approved as monotherapy in metastatic castration-resistant PCa, thereby establishing the first biomarker-guided drug indications in PCa. Several combinations of PARPi with androgen receptor pathway inhibitors have now also been approved. Anemia and fatigue are the main adverse events associated with this drug class in clinical trials; gastrointestinal toxicities are common but usually manageble.

CONCLUSIONS AND CLINICAL IMPLICATIONS

PARPi are active against PCa with HRR mutations, especially in those with germline or somatic BRCA1/2 mutations.  There is still a need to further optimize patient stratification strategies, particularly for combination approaches. Future research should focus on refining predictive biomarkers, improving treatment delivery strategies, and exploring the potential benefits of PARPi in earlier stages of the disease.

PATIENT SUMMARY

Here, we summarize the results from clinical trials testing different poly (ADP-ribose) polymerase inhibitors (PARPi), a novel targeted drug class, in prostate cancer. Overall, the data from these trials confirm the efficacy of this drug class in those metastatic prostate cancers that show specific gene alterations, such as mutations in the BRCA1/2 genes. Several studies combining PARPi with other standard drugs for prostate cancer suggest that there may be efficacy in larger patient populations, but some of these data still need validation in longer follow-up analyses.

Nivolumab in Patients with Metastatic Castration-Resistant Prostate Cancer with and without DNA Repair Defects

PURPOSE

Despite the success of immune checkpoint inhibitors (ICI) across various cancers, their efficacy in metastatic castration-resistant prostate cancer (mCRPC) is modest, except for a subset of patients who experience significant, yet unpredictable, benefits. DNA repair defects (DRD) are associated with higher neoantigen load, which may predict response. Our study explored the potential of DRD for enhanced responsiveness to the ICI nivolumab.

PATIENTS AND METHODS

We conducted a phase II, multicenter, single-arm trial evaluating nivolumab in patients with mCRPC with prior docetaxel therapy. The DRD were assessed using ctDNA. The primary endpoint was PSA50 response. Secondary endpoints included the objective response rate, radiographic progression-free survival (rPFS), and overall survival. Also, exploratory comprehensive genomic profiling was performed via whole-exome sequencing of tumor samples and matched normal tissues, alongside PD-L1 expression evaluation.

RESULTS

Among the 38 enrolled patients, DRD was identifiable in 30.5% (11/36) through ctDNA and/or whole-exome sequencing analyses. The overall PSA50 response rate was 10.5% (4/38). The PSA50 and objective response rates did not significantly differ between patients with and without DRD (18.2% vs. 8%; P = 0.57 and 50% vs. 17.6%; P = 0.27, respectively). The median PSA-PFS (1.9 vs. 2.8 months; P = 0.52) and rPFS (3.4 vs. 5.5 months; P = 0.7) were not statistically different between patients with and without DRD. Grade ≥ 3 adverse events were reported in 47.3% of participants.

CONCLUSIONS

Nivolumab has clinical activity in a subset of patients with mCRPC; however, DRD does not predict response. These results highlight the necessity of identifying new biomarkers to more accurately determine patients with mCRPC who might respond to ICIs.

ELAVL1 regulates PD-L1 mRNA stability to disrupt the infiltration of CD4-positive T cells in prostate cancer

Prostate cancer (PCa) currently ranks second in male tumor mortality. Targeting immune checkpoint in tumor as immunotherapy is a new direction for tumor treatment. However, targeting PD-1/PD-L1 and CTLA4 to treat PCa has poor immunotherapeutic efficacy because PCa is known as a cold tumor. Understanding the mechanism of immunosuppression in PCa can promote the use of immunotherapy to treat PCa. ELAVL1 is highly expressed in many tumors, participates in almost all tumor biological activities and is an oncogene. ELAVL1 is also involved in the development and differentiation of T and B lymphocytes. However, the relationship between ELAVL1 and tumor immunity has not yet been reported. In recent years, ELAVL1 has been shown to regulate downstream targets in an m6A -dependent manner. PD-L1 has been shown to have m6A sites in multiple tumors that are regulated by m6A. In this study, ELAVL1 was highly expressed in PCa, and PCa with high ELAVL1 expression is immunosuppressive. Knocking down ELAVL1 reduced PD-L1 expression in PCa. Moreover, PD-L1 was shown to have an m6A site, and its m6A level was upregulated in PCa. ELAVL1 interacts with PD-L1 mRNA and promotes PD-L1 RNA stability via m6A, ultimately inhibiting the infiltration of CD4-positive T cells. In addition, androgen receptor (AR) was shown to be regulated with ELAVL1, and knocking down AR could also affect the expression of PD-L1. Therefore, ELAVL1 can directly or indirectly regulate the expression of PD-L1, thereby affecting the infiltration of CD4-positive T cells in PCa and ultimately leading to immune suppression.

Hepatic arterial infusion of GEMOX plus systemic gemcitabine chemotherapy combined with lenvatinib and PD-1 inhibitor in large unresectable intrahepatic cholangiocarcinoma

PURPOSE

To assess the efficacy and safety of hepatic arterial infusion chemotherapy (HAIC) of gemcitabine and oxaliplatin (GEMOX) plus systemic gemcitabine chemotherapy (GEM-SYS) in combination with lenvatinib and programmed cell death protein-1 (PD-1) inhibitor for patients with large unresectable intrahepatic cholangiocarcinoma (uICC).

METHODS

From November 2019 to December 2022, 21 large uICC patients who underwent GEMOX-HAIC (Day 1) and GEM-SYS (Day 8) (3w/cycle) combined with lenvatinib and PD-1 inhibitor were retrospectively enrolled. Local tumor response, progression-free survival (PFS), overall survival (OS), and adverse events (AEs) were analyzed. Tumor response was assessed by the Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1. AEs were evaluated by the common terminology criteria for adverse events (CTCAE) version 5.0.

RESULTS

After a median follow-up duration of 16.0 months (range 5-43.5 months), 17 patients had died. The median OS was 19.5 months (range 9-43.5 months), and the median PFS was 6.0 months (range 2.5-38.5 months). The 1-, 2-, and 3-year OS rates were 71.4 %, 42.9 %, and 19.0 %, respectively. The 1-, 2-, and 3-year PFS rates were 33.3 %, 19.0 %, and 9.5 %, respectively. Complete response, partial response, stable disease, and progressive disease were observed in 0 (0 %), 11 (52.3 %), 5 (23.8 %), and 5 (23.8 %) patients, respectively. The disease control rate and objective response rate were 76.1 % and 52.3 %, respectively. None of the enrolled patients experienced grade 5 AEs.

CONCLUSIONS

GEMOX-HAIC plus GEM-SYS in combination with lenvatinib and PD-1 inhibitor was effective and well tolerated for patients with large uICC.

Intrinsic ADRB2 inhibition improves CAR-T cell therapy efficacy against prostate cancer

Chimeric antigen receptor (CAR)-T cell therapy has shown limited success in patients with solid tumors. Recent in vitro and in vivo data have shown that adrenoceptor beta-2 (ADRB2) is a novel checkpoint receptor that inhibits T cell-mediated anti-tumor responses. To inhibit ADRB2-mediated inhibitory signaling, we downregulated ADRB2 in CAR-T (shβ2-CAR-T) cells via RNA interference, assessed different parameters, and compared them with conventional second-generation CAR-T cells. ADRB2 knockdown CAR-T cells exhibited enhanced cytotoxicity against prostate cancer cell lines in vitro, by increasing CD69, CD107a, GzmB, IFN-γ, T-bet, and GLUT-1. In addition, ADRB2 deficiency led to improved proliferation, increased CD8/CD4 T cell ratio, and decreased apoptosis in CAR-T cells. shβ2-CAR-T cells expressed more Bcl-2 and led to the generation of more significant proportions of T central memory cells. Finally, the ZAP-70/NF-κB signaling axis was shown to be responsible for the improved functions of novel CAR-T cells. In tumor-bearing mice, shβ2-CAR-T cells performed better than conventional CAR-T cells in eradicating prostate tumors. The study provides the basis for future clinical and translational CAR-T cell research to focus on adrenergic stress-mediated challenges in the tumor microenvironment of stressed tumors.

Epitranscriptomic mechanisms of androgen signalling and prostate cancer

Prostate cancer (PCa) is the second most common cancer diagnosed in men. While radical prostatectomy and radiotherapy are often successful in treating localised disease, post-treatment recurrence is common. As the androgen receptor (AR) and androgen hormones play an essential role in prostate carcinogenesis and progression, androgen deprivation therapy (ADT) is often used to deprive PCa cells of the pro-proliferative effect of androgens. ADTs act by either blocking androgen biosynthesis (e.g. abiraterone) or blocking AR function (e.g. bicalutamide, enzalutamide, apalutamide, darolutamide). ADT is often effective in initially suppressing PCa growth and progression, yet emergence of castrate-resistant PCa and progression to neuroendocrine-like PCa following ADT are major clinical challenges. For this reason, there is an urgent need to identify novel approaches to modulate androgen signalling to impede PCa progression whilst also preventing or delaying therapy resistance. The mechanistic convergence of androgen and epitranscriptomic signalling offers a potential novel approach to treat PCa. The epitranscriptome involves covalent modifications of mRNA, notably, in the context of this review, the N(6)-methyladenosine (m6A) modification. m6A is involved in the regulation of mRNA splicing, stability, and translation, and has recently been shown to play a role in PCa and androgen signalling. The m6A modification is dynamically regulated by the METTL3-containing methyltransferase complex, and the FTO and ALKBH5 RNA demethylases. Given the need for novel approaches to treat PCa, there is significant interest in new therapies that target m6A that modulate AR expression and androgen signalling. This review critically summarises the potential benefit of such epitranscriptomic therapies for PCa patients.

Patterns and Frequency of Pathogenic Germline Variants Among Prostate Cancer Patients Utilizing Multi-Gene Panel Genetic Testing

Background

Germline genetic testing (GGT) has significant implications in the management of patients with prostate cancer (PCa). Herein, we report on patterns and frequency of pathogenic/likely pathogenic germline variants (P/LPGVs) among newly diagnosed Arab patients with PCa.

Methods

Patients meeting the National Comprehensive Cancer Network (NCCN) eligibility criteria for GGT were offered a 19-gene PCa panel or an expanded 84-gene multi-cancer panel.

Results

During the study period, 231 patients were enrolled; 107 (46.3%) had metastatic disease at diagnosis. In total, 17 P/LPGVs were detected in 17 patients (7.4%). Among the 113 (48.9%) patients who underwent GGT with the 19-gene panel, eight (7.1%) had P/LPGVs, compared to nine (7.6%) of the 118 (51.1%) who did GGT through the expanded 84-gene panel (P = 0.88). Variant of uncertain significance (VUS) rate was higher (n = 73, 61.9%) among the group who underwent expanded 84-gene panel testing compared to those who underwent the 19-gene PCa panel (n = 35, 30.9%) (P = 0.001). P/LPGVs in DNA damage repair (DDR) genes, most frequently BRCA2, CHEK2 and TP53, were the most common P/LPGVs findings.

Conclusion

This study is the first to characterize the germline genetic profile of an Arab population with PCa. All detected P/LPGVs were potentially actionable, with most variants able to be detected with a PCa-specific panel.

Advances in and prospects of immunotherapy for prostate cancer

Immunotherapy has shown promising therapeutic effects in hematological malignancies and certain solid tumors and has emerged as a critical and highly potential treatment modality for cancer. However, prostate cancer falls under the category of immune-resistant cold tumors, for which immunotherapy exhibits limited efficacy in patients with solid tumors. Thus, it is important to gain a deeper understanding of the tumor microenvironment in prostate cancer to facilitate immune system activation and overcome immune suppression to advance immunotherapy for prostate cancer. In this review, we discuss the immunosuppressive microenvironment of prostate cancer, which is characterized by the presence of few tumor-infiltrating lymphocytes, abundant immunosuppressive cells, low immunogenicity, and a noninflammatory phenotype, which significantly influences the efficacy of immunotherapy for prostate cancer. Immunotherapy is mainly achieved by activating the host immune system and overcoming immunosuppression. In this regard, we summarize the therapeutic advances in immune checkpoint blockade, immunogenic cell death, reversal of the immunosuppressive tumor microenvironment, tumor vaccines, immune adjuvants, chimeric antigen receptor T-cell therapy, and overcoming penetration barriers in prostate cancer, with the aim of providing novel research insights and approaches to enhance the effectiveness of immunotherapy for prostate cancer.

Overexpression of DUSP26 gene suppressed the proliferation, migration, and invasion of human prostate cancer cells

Prostate cancer (PCa) is threatening the health of millions of people, the pathological mechanism of prostate cancer has not been fully elaborated, and needs to be further explored. Here, we found that the expression of DUSP26 is dramatically suppressed, and a positive connection of its expression with PCa prognosis was also observed. In vitro, overexpression of DUSP26 significantly inhibited the proliferative, migrative, and invasive capacities of PC3 cells, DUSP26 silencing presented opposite results. Tumor formation experiments in subcutaneous nude mice demonstrated that DUSP26 overexpression could significantly suppress PC3 growth in vivo. Moreover, the mechanism of DUSP26 gene and PCa was discovered by RNA-Seq analysis. We found that DUSP26 significantly inhibited MAPK signaling pathway activation, and further experiments displayed that DUSP26 could impair TAK1, p38, and JNK phosphorylation. Interestingly, treatment with the TAK1 inhibitor (iTAK1) attenuated the effect of DUSP26 on PC3 cells. Together, these results suggested that DUSP26 may serve as a novel therapeutic target for PC3 cell type PCa, the underlying mechanism may be through TAK1-JNK/p38 signaling.

MYC and p53 alterations cooperate through VEGF signaling to repress cytotoxic T cell and immunotherapy responses in prostate cancer

Patients with castration-resistant prostate cancer (CRPC) are generally unresponsive to tumor targeted and immunotherapies. Whether genetic alterations acquired during the evolution of CRPC impact immune and immunotherapy responses is largely unknown. Using our innovative electroporation-based mouse models, we generated distinct genetic subtypes of CRPC found in patients and uncovered unique immune microenvironments. Specifically, mouse and human prostate tumors with MYC amplification and p53 disruption had weak cytotoxic lymphocyte infiltration and an overall dismal prognosis. MYC and p53 cooperated to induce tumor intrinsic secretion of VEGF, which by signaling through VEGFR2 expressed on CD8+ T cells, could directly inhibit T cell activity. Targeting VEGF-VEGFR2 signaling in vivo led to CD8+ T cell-mediated tumor and metastasis growth suppression and significantly increased overall survival in MYC and p53 altered CPRC. VEGFR2 blockade also led to induction of PD-L1, and in combination with PD-L1 immune checkpoint blockade produced anti-tumor efficacy in multiple preclinical CRPC mouse models. Thus, our results identify a genetic mechanism of immune suppression through VEGF signaling in prostate cancer that can be targeted to reactivate immune and immunotherapy responses in an aggressive subtype of CRPC.

Significance

Though immune checkpoint blockade (ICB) therapies can achieve curative responses in many treatment-refractory cancers, they have limited efficacy in CRPC. Here we identify a genetic mechanism by which VEGF contributes to T cell suppression, and demonstrate that VEGFR2 blockade can potentiate the effects of PD-L1 ICB to immunologically treat CRPC.

The Role of Natural Killer Cells in Oncolytic Virotherapy: Friends or Foes?

Oncolytic virotherapy (OVT) has emerged as a promising cancer immunotherapy, and is capable of potentiating other immunotherapies due to its capacity to increase tumor immunogenicity and to boost host antitumor immunity. Natural killer (NK) cells are a critical cellular component for mediating the antitumor response, but hold a mixed reputation for their role in mediating the therapeutic efficacy of OVT. This review will discuss the pros and cons of how NK cells impact OVT, and how to harness this knowledge for the development of effective strategies that could modulate NK cells to improve OVT-based therapeutic outcomes.

Pembrolizumab plus Abiraterone Acetate and Prednisone in Patients with Chemotherapy-naïve Metastatic Castration-resistant Prostate Cancer: Results from KEYNOTE-365 Cohort D

BACKGROUND AND OBJECTIVE

Abiraterone acetate (abiraterone) plus prednisone is approved for the treatment of metastatic castration-resistant prostate cancer (mCRPC). Our aim was to evaluate the efficacy and safety of pembrolizumab plus abiraterone in mCRPC.

METHODS

In cohort D of the phase 1b/2 KEYNOTE-365 study (NCT02861573), patients were chemotherapy-naïve, had disease progression ≤6 mo before screening, and had either not received prior next-generation hormonal agents for mCRPC or had received prior enzalutamide for mCRPC and had disease progression or became intolerant to enzalutamide. Patients received pembrolizumab 200 mg intravenously every 3 wk plus abiraterone 1000 mg orally once daily and prednisone 5 mg orally twice daily. The primary endpoints were safety, prostate-specific antigen (PSA) response rate, and objective response rate (ORR) according to Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST v1.1) by blinded independent central review (BICR). Secondary endpoints included radiographic progression-free survival (rPFS) according to Prostate Cancer Clinical Trials Working Group 3-modified RECIST v1.1 by BICR and overall survival (OS).

KEY FINDINGS AND LIMITATIONS

For the 103 patients who were treated, median follow-up was 28 mo (interquartile range 26-31). The confirmed PSA response rate was 56% (58/103 patients). The ORR for patients with RECIST v1.1-measurable disease was 16% (6/37 patients). Median rPFS was 15 mo (95% confidence interval 9.2-22) and median OS was 30 mo (95% confidence interval 23-not reached); the estimated 24-mo OS rate was 58%. In total, 91% of patients experienced treatment-related adverse events, and 39% experienced grade 3-5 events. Grade 3/4 elevation of alanine aminotransferase (ALT) or aspartate aminotransferase (AST) was observed in 12% and 6.8% of patients, respectively. One patient died due to treatment-related myasthenic syndrome. Study limitations include the single-arm design.

CONCLUSIONS

Pembrolizumab plus abiraterone and prednisone demonstrated antitumor activity and acceptable safety in patients with chemotherapy-naïve mCRPC. Higher incidence of grade 3/4 elevated ALT/AST occurred than was reported for the individual agents.

PATIENT SUMMARY

For patients with metastatic castratation-resistant prostate cancer, the drug combination of pembrolizumab plus abiraterone and prednisone showed antitumor activity and acceptable safety.

Starving cancer cells to enhances DNA damage and immunotherapy response

Prostate cancer (PCa) poses significant challenges in treatment, particularly when it progresses to a metastatic, castrate-resistant state. Conventional therapies, including chemotherapy, radiotherapy, and hormonal treatments, often fail due to toxicities, off-target effects, and acquired resistance. This research perspective defines an alternative therapeutic strategy focusing on the metabolic vulnerabilities of PCa cells, specifically their reliance on non-essential amino acids such as cysteine. Using an engineered enzyme cyst(e)inase to deplete the cysteine/cystine can induce oxidative stress and DNA damage in cancer cells. This depletion elevates reactive oxygen species (ROS) levels, disrupts glutathione synthesis, and enhances DNA damage, leading to cancer cell death. The combinatorial use of cyst(e)inase with agents targeting antioxidant defenses, such as thioredoxins, further amplifies ROS accumulation and cytotoxicity in PCa cells. Overall, in this perspective provides a compressive overview of the previous work on manipulating amino acid metabolism and redox balance modulate the efficacy of DNA repair-targeted and immune checkpoint blockade therapies in prostate cancer.

Androgen receptor, PARP signaling, and tumor microenvironment: the 'perfect triad' in prostate cancer?

Aberrations in the homologous recombination repair (HRR) pathway in prostate cancer (PCa) provide a unique opportunity to develop therapeutic strategies that take advantage of the reduced tumor ability to repair DNA damage. Poly-ADP-ribose polymerase (PARP) inhibitors (PARPi) have been shown to prolong the survival of PCa patients with HRR defects, particularly in those with Breast Cancer type 1 susceptibility protein/Breast Cancer type 2 susceptibility protein alterations. To expand the benefit of PARPi to patients without detectable HRR alterations, multiple preclinical and clinical studies are addressing potential synergies between PARPi and androgen receptor signaling inhibitors, and these strategies are also being evaluated in combination with other drugs such as immune checkpoint inhibitors. However, the effectiveness of these combining therapies could be hindered by multiple mechanisms of resistance, including also the role played by the immunosuppressive tumor microenvironment. In this review, we summarize the use of PARPi in PCa and the potential synergies with different molecular pathways. However, numerous unanswered questions remain, including the identification of the patient population that could benefit most from PARPi, determining whether to use PARPi as monotherapy or in combination, and finding the optimal timing of PARPi, expanding the use of genomic tests, and optimizing combination therapies.

Pembrolizumab and Enzalutamide in Patients with Abiraterone Acetate-Pretreated Metastatic Castration-Resistant Prostate Cancer: Cohort C of the Phase 1b/2 KEYNOTE-365 Study

BACKGROUND

Limited responses have been observed in patients treated with enzalutamide after disease progression on abiraterone for metastatic castration-resistant prostate cancer (mCRPC), but androgen receptor signaling impacts T-cell function.

OBJECTIVE

To evaluate the efficacy and safety of pembrolizumab plus enzalutamide in mCRPC.

DESIGN, SETTING, AND PARTICIPANTS

Patients in cohort C of the phase 1b/2 KEYNOTE-365 study, who received ≥4 wk of treatment with abiraterone acetate in the prechemotherapy mCRPC state and experienced treatment failure or became drug-intolerant, were included.

INTERVENTION

Pembrolizumab 200 mg intravenously every 3 wk plus enzalutamide 160 mg orally once daily.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary endpoints were safety, the confirmed prostate-specific antigen (PSA) response rate, and the objective response rate (ORR) according to Response Evaluation Criteria in Solid Tumors version 1.1 on blinded independent central review (BICR). Secondary endpoints included radiographic progression-free survival (rPFS) on BICR and overall survival (OS).

RESULTS AND LIMITATIONS

A total of 102 patients received pembrolizumab plus enzalutamide. Median follow-up was 51 mo (interquartile range 37-56). The confirmed PSA response rate was 24% (95% confidence interval [CI] 16-33%). The confirmed ORR was 11% (95% CI 2.9-25%; 4/38 patients; two complete responses). Median rPFS was 6.0 mo (95% CI 4.1-6.3). Median OS was 20 mo (95% CI 17-24). Treatment-related adverse events (TRAEs) occurred in 94 patients (92%); grade 3-5 TRAEs occurred in 44 patients (43%). The incidence of treatment-related rash was higher with combination therapy than expected from the safety profile of each drug. One patient (1.0%) died of a TRAE (cause unknown). Study limitations include the single-arm design.

CONCLUSIONS

Pembrolizumab plus enzalutamide had limited antitumor activity in patients who received prior abiraterone treatment without previous chemotherapy for mCRPC, with a safety profile consistent with the individual profiles of each agent.

PATIENT SUMMARY

Pembrolizumab plus enzalutamide showed limited antitumor activity and manageable safety in patients with metastatic castration-resistant prostate cancer. The KEYNOTE-365 trial is registered on ClinicalTrials.gov as NCT02861573.

Assessment of PSA responses and changes in the rate of tumor growth (g-rate) with immune checkpoint inhibitors in US Veterans with prostate cancer

We examined data from US Veterans with prostate cancer (PC) to assess disease response to immune checkpoint inhibitors (ICI) as monotherapy or combined with abiraterone or enzalutamide to assess ICI efficacy in the real-world. We queried the VA corporate data warehouse (CDW) to identify Veterans with a diagnosis of PC who received ICI for any malignancy and had ≥1 PSA measurement while receiving ICI. To evaluate ICI monotherapy, we restricted analysis to Veterans who had not received LHRH agonists/antagonists, PC-directed medical therapy, or radiation/extirpative surgery of the bladder/prostate within and preceding the duration of ICI administration. For ICI combination analysis, we identified Veterans who received abiraterone or enzalutamide for PC while on ICI. We calculated rates of tumor (PSA) growth (g-rates), comparing them to a 1:2 matched reference cohort. We identified 787 Veterans with PC and ≥1 PSA measurement while receiving an ICI. Median duration of ICI therapy was 155 days. 223 Veterans received ICI monotherapy, with only 17(8%) having a reduction in PSA (median decline = 43%). 12 (5%) had PSA declines >30% (PSA30) which included 6 (3%) who had PSA reductions greater than 50% (PSA50). Median g-rates for ICI plus abiraterone (n = 20) or enzalutamide (n = 31) were 0.000689/d-1 and 0.002819/d-1, respectively, and were statistically insignificant compared to g-rates of matched cohorts receiving abiraterone (g = 0.000925/d-1, P = 0.73) or enzalutamide (g = 0.001929/d-1, P = 0.58) alone. Our data align with clinical trial data in PC, demonstrating limited benefit from ICI monotherapy and predicting no survival benefit from simultaneous abiraterone or enzalutamide with an ICI using g-rate.

The Evolving Landscape of Biomarkers for Immune Checkpoint Blockade in Genitourinary Cancers

In the past decade, immune checkpoint inhibitors (ICI) have been approved for treatment of genitourinary malignancies and have revolutionized the treatment landscape of these tumors. However, despite the remarkable success of these therapies in some GU malignancies, many patients' tumors do not respond to these therapies, and others may experience significant side effects, such as immune-related adverse events (iRAEs). Accordingly, biomarkers and improved prognostic tools are critically needed to help predict which patients will respond to ICI, predict and mitigate risk of developing immune-related adverse events, and inform personalized choice of therapy for each patient. Ongoing clinical and preclinical studies continue to provide an increasingly robust understanding of the mechanisms of the response to immunotherapy, which continue to inform biomarker development and validation. Herein, we provide a comprehensive review of biomarkers of the response to immunotherapy in GU tumors and their role in selection of therapy and disease monitoring.

Bi-specific T-cell engagers (BiTEs) in prostate cancer and strategies to enhance development: hope for a BiTE-r future

Metastatic castrate resistant prostate cancer (mCRPC) continues to have poor survival rates due to limited treatment options. Bi-specific T cell engagers (BiTEs) are a promising class of novel immunotherapies with demonstrated success in haematological malignancies and melanoma. BiTEs developed for tumour associated antigens in prostate cancer have entered clinical testing. These trials have been hampered by high rates of treatment related adverse events, minimal or transient anti-tumour efficacy and generation of high titres of anti-drug antibodies. This paper aims to analyse the challenges faced by the different BiTE therapy constructs and the mCRPC tumour microenvironment that result in therapeutic resistance and identify possible strategies to overcome these issues.

Novel frontiers in urogenital cancers: from molecular bases to preclinical models to tailor personalized treatments in ovarian and prostate cancer patients

Over the last few decades, the incidence of urogenital cancers has exhibited diverse trends influenced by screening programs and geographical variations. Among women, there has been a consistent or even increased occurrence of endometrial and ovarian cancers; conversely, prostate cancer remains one of the most diagnosed malignancies, with a rise in reported cases, partly due to enhanced and improved screening efforts.Simultaneously, the landscape of cancer therapeutics has undergone a remarkable evolution, encompassing the introduction of targeted therapies and significant advancements in traditional chemotherapy. Modern targeted treatments aim to selectively address the molecular aberrations driving cancer, minimizing adverse effects on normal cells. However, traditional chemotherapy retains its crucial role, offering a broad-spectrum approach that, despite its wider range of side effects, remains indispensable in the treatment of various cancers, often working synergistically with targeted therapies to enhance overall efficacy.For urogenital cancers, especially ovarian and prostate cancers, DNA damage response inhibitors, such as PARP inhibitors, have emerged as promising therapeutic avenues. In BRCA-mutated ovarian cancer, PARP inhibitors like olaparib and niraparib have demonstrated efficacy, leading to their approval for specific indications. Similarly, patients with DNA damage response mutations have shown sensitivity to these agents in prostate cancer, heralding a new frontier in disease management. Furthermore, the progression of ovarian and prostate cancer is intricately linked to hormonal regulation. Ovarian cancer development has also been associated with prolonged exposure to estrogen, while testosterone and its metabolite dihydrotestosterone, can fuel the growth of prostate cancer cells. Thus, understanding the interplay between hormones, DNA damage and repair mechanisms can hold promise for exploring novel targeted therapies for ovarian and prostate tumors.In addition, it is of primary importance the use of preclinical models that mirror as close as possible the biological and genetic features of patients' tumors in order to effectively translate novel therapeutic findings "from the bench to the bedside".In summary, the complex landscape of urogenital cancers underscores the need for innovative approaches. Targeted therapy tailored to DNA repair mechanisms and hormone regulation might offer promising avenues for improving the management and outcomes for patients affected by ovarian and prostate cancers.

Innovative Drug Modalities for the Treatment of Advanced Prostate Cancer

Prostate cancer, a prevalent malignancy affecting the prostate gland, is a significant global health concern. Androgen-deprivation therapy (ADT) has proven effective in controlling advanced disease, with over 50% of patients surviving at the 10-year mark. However, a diverse spectrum of responses exists, and resistance to ADT may emerge over time. This underscores the need to explore innovative treatment strategies for effectively managing prostate cancer progression. Ongoing research endeavors persist in unraveling the complexity of prostate cancer and fostering the development of biologic and innovative approaches, including immunotherapies and targeted therapies. This review aims to provide a valuable synthesis of the dynamic landscape of emerging drug modalities in this context. Interestingly, the complexities posed by prostate cancer not only present a formidable challenge but also serve as a model and an opportunity for translational research and innovative therapies in the field of oncology.

Complications of immuno-oncology care: what urologist should know

OBJECTIVES

To provide a practical review of immune-related adverse events (irAEs) that may be encountered in uro-oncology patients.

PATIENTS AND METHODS

We conducted a literature review of studies reporting irAEs including articles published through September 2023 for uro-oncology patients and the potential relevancy for the practicing urologist.

RESULTS

Immunotherapy has revolutionised cancer treatment, extending its impact to urological malignancies including for patients with urothelial, kidney, and prostate cancers. Immuno-oncology (IO) compounds have achieved measurable and durable responses in these cancers. Urologists, choosing to administer or co-manage IO patient care, should be prepared to understand, evaluate, and treat irAEs. This review discusses the spectrum of irAEs that can be encountered. Ongoing trials are exploring the use of immunotherapy at earlier stages of uro-oncological diseases, thus underscoring the evolving landscape of urological cancer treatment. Paradoxically, some data suggests that the occurrence of irAEs is associated with improved oncological outcomes.

CONCLUSIONS

Immune-related AEs, while manageable, may be life-threatening and require lifelong therapy. A thorough understanding of AEs and toxicity of a novel drug class is imperative.

The implications of single-cell RNA-seq analysis in prostate cancer: unraveling tumor heterogeneity, therapeutic implications and pathways towards personalized therapy

In recent years, advancements in single-cell and spatial transcriptomics, which are highly regarded developments in the current era, particularly the emerging integration of single-cell and spatiotemporal transcriptomics, have enabled a detailed molecular comprehension of the complex regulation of cell fate. The insights obtained from these methodologies are anticipated to significantly contribute to the development of personalized medicine. Currently, single-cell technology is less frequently utilized for prostate cancer compared with other types of tumors. Starting from the perspective of RNA sequencing technology, this review outlined the significance of single-cell RNA sequencing (scRNA-seq) in prostate cancer research, encompassing preclinical medicine and clinical applications. We summarize the differences between mouse and human prostate cancer as revealed by scRNA-seq studies, as well as a combination of multi-omics methods involving scRNA-seq to highlight the key molecular targets for the diagnosis, treatment, and drug resistance characteristics of prostate cancer. These studies are expected to provide novel insights for the development of immunotherapy and other innovative treatment strategies for castration-resistant prostate cancer. Furthermore, we explore the potential clinical applications stemming from other single-cell technologies in this review, paving the way for future research in precision medicine.

Repeat Next-Generation Sequencing Testing on Progression in Men With Metastatic Prostate Cancer Can Identify New Actionable Alterations

PURPOSE

There are limited data available on the real-world patterns of molecular testing in men with advanced prostate cancer. We thus sought to evaluate next-generation sequencing (NGS) testing in the United States, focused on single versus serial NGS testing, the different disease states of testing (hormone-sensitive v castration-resistant, metastatic vs nonmetastatic), tissue versus plasma circulating tumor DNA (ctDNA) assays, and how often actionable data were found on each NGS test.

METHODS

The Prostate Cancer Precision Medicine Multi-Institutional Collaborative Effort clinical-genomic database was used for this retrospective analysis, including 1,597 patients across 15 institutions. Actionable NGS data were defined as including somatic alterations in homologous recombination repair genes, mismatch repair deficiency, microsatellite instability (MSI-high), or a high tumor mutational burden ≥10 mut/MB.

RESULTS

Serial NGS testing (two or more NGS tests with specimens collected more than 60 days apart) was performed in 9% (n = 144) of patients with a median of 182 days in between test results. For the second NGS test and beyond, 82.1% (225 of 274) of tests were from ctDNA assays and 76.1% (217 of 285) were collected in the metastatic castration-resistant setting. New actionable data were found on 11.1% (16 of 144) of second NGS tests, with 3.5% (5 of 144) of tests detecting a new BRCA2 alteration or MSI-high. A targeted therapy (poly (ADP-ribose) polymerase inhibitor or immunotherapy) was given after an actionable result on the second NGS test in 31.3% (5 of 16) of patients.

CONCLUSION

Repeat somatic NGS testing in men with prostate cancer is infrequently performed in practice and can identify new actionable alterations not present with initial testing, suggesting the utility of repeat molecular profiling with tissue or blood of men with metastatic castration-resistant prostate cancer to guide therapy choices.

Moving toward improved immune checkpoint immunotherapy for advanced prostate cancer

Human prostate cancer is a heterogenous malignancy that responds poorly to immunotherapy targeting immune checkpoints. The immunosuppressive tumor microenvironment that is typical of human prostate cancer has been the main obstacle to these treatments. The effectiveness of these therapies is also hindered by acquired resistance, leading to slow progress in prostate cancer immunotherapy. Results from the highly anticipated late-stage clinical trials of PD-1/PD-L1 immune checkpoint blockade in patients with advanced prostate cancer have highlighted some of the obstacles to immunotherapy. Despite the setbacks, there is much that has been learned about the mechanisms that drive resistance, and new strategies are being developed and tested. Here, we review the status of immune checkpoint blockade and the immunosuppressive tumor microenvironment and discuss factors contributing to innate and adaptive resistance to immune checkpoint blockade within the context of prostate cancer. We then examine current strategies aiming to overcome these challenges as well as prospects.

Paraneoplastic Syndromes in Neuroendocrine Prostate Cancer: A Systematic Review

Neuroendocrine prostate cancer (NEPC) is a rare subtype of prostate cancer (PCa) that usually results in poor clinical outcomes and may be accompanied by paraneoplastic syndromes (PNS). NEPC is becoming more frequent. It can initially manifest as PNS, complicating diagnosis. Therefore, we reviewed the literature on the different PNS associated with NEPC. We systematically reviewed English-language articles from January 2017 to September 2023, identifying 17 studies meeting PRISMA guidelines for NEPC and associated PNS. A total of 17 articles were included in the review. Among these, Cushing's Syndrome (CS) due to ectopic Adrenocorticotropic hormone (ACTH) secretion was the most commonly reported PNS. Other PNS included syndrome of inappropriate Anti-Diuretic Hormone secretion (SIADH), Anti-Hu-mediated chronic intestinal pseudo-obstruction (CIPO), limbic encephalitis, Evans Syndrome, hypercalcemia, dermatomyositis, and polycythemia. Many patients had a history of prostate adenocarcinoma treated with androgen deprivation therapy (ADT) before neuroendocrine features developed. The mean age was 65.5 years, with a maximum survival of 9 months post-diagnosis. NEPC is becoming an increasingly more common subtype of PCa that can result in various PNS. This makes the diagnosis and treatment of NEPC challenging. Further research is crucial to understanding these syndromes and developing standardized, targeted treatments to improve patient survival.

The radiopharmaceutical radium-223 has immunomodulatory effects in patients and facilitates anti-programmed death receptor-1 therapy in murine models of bone metastatic prostate cancer

BACKGROUND & PURPOSE

Radium-223 (Ra223) improves survival in metastatic prostate cancer (mPC), but its impact on systemic immunity is unclear, and biomarkers of response are lacking. We examined markers of immunomodulatory activity during standard clinical Ra223 and studied the impact of Ra223 on response to immune checkpoint inhibition (ICI) in preclinical models.

MATERIALS & METHODS

We conducted a single-arm biomarker study of Ra223 in 22 bone mPC patients. We measured circulating immune cell subsets and a panel of cytokines before and during Ra223 therapy and correlated them with overall survival (OS). Using two murine mPC models-orthotopic PtenSmad4-null and TRAMP-C1 grafts in syngeneic immunocompetent mice-we tested the efficacy of combining Ra223 with ICI.

RESULTS

Above-median level of IL-6 at baseline was associated with a median OS of 358 versus 947 days for below levels; p = 0.044, from the log-rank test. Baseline PlGF and PSA inversely correlated with OS (p = 0.018 and p = 0.037, respectively, from the Cox model). Ra223 treatment was associated with a mild decrease in some peripheral immune cell populations and a shift in the proportion of MDSCs from granulocytic to myeloid. In mice, Ra223 increased the proliferation of CD8+ and CD4+ helper T cells without leading to CD8+ T cell exhaustion in the mPC lesions. In one of the models, combining Ra223 and anti-PD-1 antibody significantly prolonged survival, which correlated with increased CD8+ T cell infiltration in tumor tissue.

CONCLUSION

The inflammatory cytokine IL-6 and the angiogenic biomarker PlGF at baseline were promising outcome biomarkers after standard Ra223 treatment. In mouse models, Ra223 increased intratumoral CD8+ T cell infiltration and proliferation and could improve OS when combined with anti-PD-1 ICI.

How to Integrate Prostate Cancer Biomarkers in Urology Clinical Practice: An Update

Nowadays, the management of prostate cancer has become more and more challenging due to the increasing number of available treatment options, therapeutic agents, and our understanding of its carcinogenesis and disease progression. Moreover, currently available risk stratification systems used to facilitate clinical decision-making have limitations, particularly in providing a personalized and patient-centered management strategy. Although prognosis and prostate cancer-specific survival have improved in recent years, the heterogenous behavior of the disease among patients included in the same risk prognostic group negatively impacts not only our clinical decision-making but also oncological outcomes, irrespective of the treatment strategy. Several biomarkers, along with available tests, have been developed to help clinicians in difficult decision-making scenarios and guide management strategies. In this review article, we focus on the scientific evidence that supports the clinical use of several biomarkers considered by professional urological societies (and included in uro-oncological guidelines) in the diagnosis process and specific difficult management strategies for clinically localized or advanced prostate cancer.

Efficacy and Safety of Programmed Death-1 (PD-1)/Programmed Death-Ligand 1 (PD-L1) Checkpoint Inhibitors in Patients With Metastatic Castration-resistant Prostate Cancer: A Systematic Review and Meta-analysis

AIMS

The aim of this systematic review with meta-analysis was to evaluate the efficacy and safety of programmed death-1 (PD-1)/programmed death-ligand 1 (PD-L1) checkpoint inhibitors in patients with metastatic castration-resistant prostate cancer (mCRPC).

MATERIALS AND METHODS

We searched PubMed, Embase and Cochrane Library until 1 July 2022 for mCRPC trials testing PD-1/PD-L1 checkpoint inhibitors. We measured the efficacy and safety using overall survival, progression-free survival (PFS), overall response rates (ORR), prostate-specific antigen (PSA) response rate or treatment-related adverse events (TRAEs). When possible, data were meta-analysed.

RESULTS

Thirteen studies involving 2533 participants were included in this meta-analysis. The pooled hazard ratio for overall survival was 0.81 (95% confidence interval 0.42-1.20, I2 = 80.3%, PHeterogeneity＜0.001) and for PFS was 0.65 (95% confidence interval 0.38-0.92, I2 = 72.2%, PHeterogeneity = 0.013). Furthermore, better ORR (relative risk = 2.77, 95% confidence interval 1.25-6.13, I2 = 0%, PHeterogeneity = 0.699) was found in PD-L1-expressing tumours. However, no statistical trends between PD-L1 status on PSA response rate (relative risk = 0.79, 95% confidence interval 0.5-1.25, I2 = 0%, PHeterogeneity = 0.953) and tumour mutational burden on ORR (relative risk = 2.53, 95% confidence interval 0.49-13.12, I2 = 74.5%, PHeterogeneity = 0.02) were observed. The pooled proportions of TRAEs and ≥ grade 3 TRAEs were 85.1% (95% confidence interval = 71.7-98.5%) and 31.6% (95% confidence interval = 18.9-44.4%), respectively.

CONCLUSIONS

This meta-analysis showed that among selected populations of men with mCRPC, anti-PD-1/PD-L1 combination treatment may significantly increase the PFS benefits. However, overall survival in mCRPC warrants further testing.

Research Progress of PD 1/PD L1 Inhibitors in the Treatment of Urological Tumors

Immune checkpoint inhibitors (ICIs) offer significant advantages for the treatment of urologic tumors, enhancing the immune function of anti-tumor T cells by inhibiting PD-1 and PDL1 binding. They have been shown to be well tolerated and remarkably effective in clinical practice, offering hope to many patients who are not well treated with conventional drugs. Clinical trials in recent years have shown that anti-PD-1 and PD-L1 antibodies have good efficacy and safety in the treatment of urologic tumors. These antibodies can be applied to a variety of urologic tumors, such as bladder cancer, renal cell carcinoma, and prostate cancer. They have been approved for the first-line treatment or as an option for follow-up therapy. By blocking the PD-1/PD-L1 signaling pathway, ICIs can release immune functions that are suppressed by tumor cells and enhance T-cell killing, thereby inhibiting tumor growth and metastasis. This therapeutic approach has achieved encouraging efficacy and improved survival for many patients. Although ICIs have shown remarkable results in the treatment of urologic tumors, some problems remain, such as drug resistance and adverse effects in some patients. Therefore, further studies remain important to optimize treatment strategies and improve clinical response in patients. In conclusion, PD-1/PD-L1 signaling pathway blockers have important research advances for the treatment of urologic tumors. Their emergence brings new hope for patients who have poor outcomes with traditional drug therapy and provides new options for immunotherapy of urologic tumors. The purpose of this article is to review the research progress of PD-1 and PD-L1 signaling pathway blockers in urologic tumors in recent years.

Pembrolizumab for metastatic castration-resistant prostate cancer: trials and tribulations

INTRODUCTION

Immunotherapies have revolutionized the management of various malignancies but have only recently been evaluated systematically in prostate cancer. Pembrolizumab, a programmed-death 1 (PD-1) blocking antibody, has been utilized in a small subset of prostate cancer patients with mismatch repair deficiency/microsatellite instability, but has now been assessed in broader populations of metastatic prostate cancer patients.

AREAS COVERED

The results of four pembrolizumab-based phase III clinical trials for metastatic castration-resistant prostate cancer (mCRPC) and metastatic hormone-sensitive prostate cancer (mHSPC) patients, including KEYNOTE-641, KEYNOTE-921, KEYNOTE-991, and KEYLYNK-010 are summarized. Programmed death-ligand 1 (PD-L1) expression, the efficacy of pembrolizumab in prostate cancer patients with certain molecular defects, and emerging pembrolizumab-based therapeutic combinations are also reviewed.

EXPERT OPINION

Pembrolizumab has not benefitted unselected metastatic prostate cancer patients when combined with chemotherapy, next-generation hormonal agents (NHA), or poly(ADP-ribose) polymerase inhibitors (PARPi). PD-L1 positivity does not predict the response to pembrolizumab in this disease. A small number of responding patients can likely be explained by rare genetic and molecular defects, and more innovative combination strategies are needed to improve outcomes in prostate cancer patients who are not sensitive to pembrolizumab. Emphasis should be placed on developing additional or alternative immuno-oncology approaches beyond classical immune checkpoint inhibition.

Changes in Perception of Cure Among Patients With Genitourinary Cancers Initiating Immune Checkpoint Inhibitors: A Longitudinal Study

BACKGROUND

We explored changes in perceptions of cure among patients with genitourinary (GU) cancers starting Immune checkpoint inhibitors (ICIs) therapy.

MATERIALS AND METHODS

This longitudinal study assessed patients before starting therapy and 3-months later with a questionnaire that included patient perceptions of ICIs and the Patient-Reported Outcomes Measurement Information System (PROMIS) Anxiety scale. General linear modeling was used to investigate changes in expectation of cure over time, and chi-square tests were used to determine the association between expectation of cure and perceptions of ICIs and anxiety.

RESULTS

A total of 45 patients were recruited (73% male, 84% diagnosed with renal cell carcinoma). The proportion of patients who possessed an accurate expectation of cure increased over time (55.6%-66.7%, P = .001). An accurate expectation of cure was associated with lower rates of anxiety over time. Patients with inaccurate expectation of cure reported more severe side effects and worse self-reported ECOG score at the follow-up assessment (P = .04).

CONCLUSION

We found that patients with GU metastatic cancer treated with ICI therapy have increasingly accurate expectations of cure over time. Accurate expectation of cure is associated with decreased anxiety. Further research is needed to fully explore this dynamic over time and help inform interventions that can help patients develop accurate expectations.

Personalized medicine for metastatic prostate cancer: The paradigm of PARP inhibitors

Despite remarkable progress in the last decade, metastatic prostate cancer (mPCa) remains incurable. The approval of PARP inhibitors (PARPis) represents a milestone in this field, which definitively enters the era of precision medicine, as mPCa is often enriched for defects of homologous recombination repair genes. PARPis are now used as single agents for patients with metastatic castration-resistant PCa. Moreover, combinations of PARPis plus androgen-receptor targeted agents and immune checkpoint inhibitors, and earlier applications of PARPis in the metastatic hormone-sensitive PCa are under evaluation, representing the possible upcoming applications of these agents. Mechanisms of sensitization and resistance have been only partially elucidated. In our review, we summarize the current clinical evidence regarding PARPis in mPCa and the future directions of these targeted agents.

Pembrolizumab in mCRPC - Combination therapies as breakthrough to success?

PURPOSE OF REVIEW

Immune checkpoint inhibitors (ICIs) have shown promising antitumor activity in various malignant diseases. This narrative review provides an update on ongoing clinical studies investigating the only FDA-approved ICI programmed death receptor 1 (PD-1) inhibitor pembrolizumab in mono- and combination therapy in patients with metastatic castration-resistant prostate cancer (mCRPC).

RECENT FINDINGS

Although most clinical trials investigating pembrolizumab as mono- or combinational therapy did not meet their primary endpoints, there exist subgroups of patients that demonstrate impressive responses rates justifying further investigation of ICI in prostate cancer. Beside combination of pembrolizumab with approved mCRPC agents, innovative approaches, like combining pembrolizumab with radioligands, deoxyribonucleic acid vaccines or innovative immunotherapeutic agents (i.e., ONC-392, AMG160, BXCL701) are ongoing exerting promising preliminary findings.

SUMMARY

ICI monotherapy seems to be effective in a small biomarker-preselected population, however, there is evidence that especially novel ICI combination approaches can improve patient survival, which could ultimately refocus and revolutionize the treatment of mCRPC.

Advances in bio-immunotherapy for castration-resistant prostate cancer

Prostate cancer is one of the significant diseases that threaten the survival of men worldwide, with the progression of androgen deprivation therapy, become much rely on it, finally, developed into castration-resistant prostate cancer (ADT). In western countries, ranks second in incidence, and in China, with increasing lifespan, the incidence of prostate cancer is rising steadily. Although chemotherapy agents, such as taxane, have achieved some efficacy, treatment failure still occur. As sensitivity of hormone levels change, the disease can progress to castrate-resistant prostate cancer. Because of the poor efficacy of traditional surgery, endocrine therapy, radiation therapy, and chemotherapy, the treatment options for castrate-resistant prostate cancer are limited. Advanced prostate cancer can progress on immunotherapy, and thus, bio -immunotherapy targeting the unique, prostate microenvironment is an important option. In this paper, we systematically revealed the role of three types of bio-immunotherapies (immune checkpoint inhibitors, tumors, vaccines, cytokines) in castrate-resistant prostate cancer, providing a reference for clinical treatment of prostate cancer.

Efficacy and safety of immune checkpoint inhibitors for patients with prostate cancer: a systematic review and meta-analysis

Immunotherapy has revolutionized the treatment paradigm of many cancers, however, its effectiveness in prostate cancer patients is still under question. In the present systematic review and meta-analysis, we sought for assessing the efficacy and safety of Immune checkpoint inhibitors (ICIs) in patients with prostate cancer. PubMed, Scopus, Web of Science, and EMBASE databases were searched on Aguste 19, 2022. Thirty five studies met the eligibility criteria. The median overall survival (mOS) of all treatments was 14.1 months, with the longest and shortest mOS was seen among patients who received anti-CTLA-4 monotherapy and anti-PD-1/PD-L1+anti-CTLA-4 regimen at 24.9 and 9.2 months, respectively. Noteworthy, all types of adverse events had the lowest incidence in the anti-PD-1/PD-L1 monotherapy group. Considering the ICI monotherapy regimens, we found that fatigue, diarrhea, and infusion reaction had the highest incidence rates. Future studies evaluating the efficacy and safety of novel combination therapies with ICIs are warranted.

Enhancing personalized immune checkpoint therapy by immune archetyping and pharmacological targeting

Immune checkpoint inhibitors (ICIs) are an expanding class of immunotherapeutic agents with the potential to cure cancer. Despite the outstanding clinical response in patient subsets, most individuals become refractory or develop resistance. Patient stratification and personalized immunotherapies are limited by the absence of predictive response markers. Recent findings show that dominant patterns of immune cell composition, T-cell status and heterogeneity, and spatiotemporal distribution of immune cells within the tumor microenvironment (TME) are becoming essential determinants of prognosis and therapeutic response. In this context, ICIs also function as investigational tools and proof of concept, allowing the validation of the identified mechanisms. After reviewing the current state of ICIs, this article will explore new comprehensive predictive markers for ICIs based on recent discoveries. We will discuss the recent establishment of a classification of TMEs into immune archetypes as a tool for personalized immune profiling, allowing patient stratification before ICI treatment. We will discuss the developing comprehension of T-cell diversity and its role in shaping the immune profile of patients. We describe the potential of strategies that score the mutual spatiotemporal modulation between T-cells and other cellular components of the TME. Additionally, we will provide an overview of a range of synthetic and naturally occurring or derived small molecules. We will compare compounds that were recently identified by in silico prediction to wet lab-validated drug candidates with the potential to function as ICIs and/or modulators of the cellular components of the TME.

Immunogenomic profiles associated with response to life-prolonging agents in prostate cancer

Prostate cancer is the most commonly diagnosed cancer but the management of advanced prostate cancer remains a therapeutic challenge, despite the survival benefits imparted by several therapeutic discoveries targeting different molecular pathways. The mechanisms of resistance to androgen deprivation and tumour progression to lethal metastatic variants are often regulated by androgen receptor (AR) bypass mechanisms and/or neuroendocrine differentiation. Moreover, recent data also suggested the involvement of adaptive and innate infiltrated immune cells in prostate tumour progression. Improvements in cancer genome analyses contributed to a better understanding of antitumour immunity and provided solutions for targeting highly cancer-specific neoantigens generated from somatic mutations in individual patients. In this review, we investigated the current knowledge on the interplay between cancer development and the complex mechanisms of immune regulation. Particularly, we focused on the role of tumour immune microenvironment, generally characterised by strong barriers for immunotherapy, and we discuss the rationale for the potential application of single agent and combination immune-targeting strategies that could lead to improved outcomes. Careful selection based on clinical and genomic factors may allow identification of patients who could benefit from this treatment approach in multiple settings (from localised to advanced prostate tumour) and in different histological subtypes (from adenocarcinoma to neuroendocrine prostate cancer).

A review of strategies to overcome immune resistance in the treatment of advanced prostate cancer

Immunotherapy has become integral in cancer therapeutics over the past two decades and is now part of standard-of-care treatment in multiple cancer types. While various biomarkers and pathway alterations such as dMMR, CDK12, and AR-V7 have been identified in advanced prostate cancer to predict immunotherapy responsiveness, the vast majority of prostate cancer remain intrinsically immune-resistant, as evidenced by low response rates to anti-PD(L)1 monotherapy. Since regulatory approval of the vaccine therapy sipuleucel-T in the biomarker-unselected population, there has not been much success with immunotherapy treatment in advanced prostate cancer. Researchers have looked at various strategies to overcome immune resistance, including the identification of more biomarkers and the combination of immunotherapy with existing effective prostate cancer treatments. On the horizon, novel drugs using bispecific T-cell engager (BiTE) and chimeric antigen receptors (CAR) technology are being explored and have shown promising early efficacy in this disease. Here we discuss the features of the tumour microenvironment that predispose to immune resistance and rational strategies to enhance antitumour responsiveness in advanced prostate cancer.