Enzalutamide in metastatic prostate cancer before chemotherapy

Correlation between E-cadherin/β-catenin, Vimentin expression, clinicopathologic features and drug resistance prediction in naïve prostate cancer: A molecular and clinical study

Although epithelial-mesenchymal markers play an important role in prostate cancer (PC), further research is needed to better understand their utility in diagnosis, cancer progression prevention, and treatment resistance prediction. Our study included 111 PC patients who underwent transurethral resection, as well as 16 healthy controls. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to examine the expression of E-cadherin, β-catenin, and Vimentin. We found that E-cadherin and β-catenin were underexpressed in primary PC tissues. E-cadherin expression was found to be inversely associated with prostate-specific antigen progression (PSA-P; serum marker of progression; p = 0.01; |r| = 0.262). Furthermore, the underexpression of two markers, E-cadherin and β-catenin, was found to be associated with advanced tumor stage and grade (p < 0.05). On the other hand, Vimentin was overexpressed in PC patients with a fold change of 2.141, and it was associated with the diagnosis, prognosis, and prediction of treatment resistance to androgen deprivation therapy (p = 0.002), abiraterone-acid (p = 0.001), and taxanes (p = 0.029). Moreover, the current study highlighted that poor survival could be significantly found in patients who progressed after primary surgery, did not use drugs, and expressed these genes aberrantly. In Cox regression multivariate analysis (p < 0.05), a positive correlation between the Vimentin marker and coronary heart disease in PC patients was identified (p = 0.034). In summary, the present study highlights the diagnostic (p < 0.001), prognostic (p < 0.001), and therapeutic potential of Vimentin in primary PC (p < 0.05), as well as its implications for cardiovascular disease. Furthermore, we confirm the potential prognostic value of E-cadherin and β-catenin.

Actinium-225-PSMA radioligand therapy of metastatic castration-resistant prostate cancer (WARMTH Act): a multicentre, retrospective study

BACKGROUND

Actinium-225 (225Ac) prostate-specific membrane antigen (PSMA) radioligand therapy (RLT) is a novel therapy for metastatic castration-resistant prostate cancer (mCRPC). We aimed to report the safety and antitumour activity of 225Ac-PSMA RLT of mCRPC in a large cohort of patients treated at multiple centres across the world.

METHODS

This retrospective study included patients treated at seven centres in Australia, India, Germany, and South Africa. We pooled data of consecutive patients of any age and Eastern Cooperative Oncology Group performance status with histopathologically confirmed adenocarcinoma of the prostate who were treated with one or more cycles of 8 MBq 225Ac-PSMA RLT administered intravenously for mCRPC. Previous lines of mCRPC treatment included taxane-based chemotherapy, androgen-receptor-axis inhibitors, lutetium-177 (177Lu) PSMA RLT, and radium-223 dichloride. The primary outcomes were overall survival and progression-free survival.

FINDINGS

Between Jan 1, 2016, and May 31, 2023, 488 men with mCRPC received 1174 cycles of 225Ac-PSMA RLT (median two cycles, IQR 2-4). The mean age of the patients was 68·1 years (SD 8·8), and the median baseline prostate-specific antigen was 169·5 ng/mL (IQR 34·6-519·8). Previous lines of treatment were docetaxel in 324 (66%) patients, cabazitaxel in 103 (21%) patients, abiraterone in 191 (39%) patients, enzalutamide in 188 (39%) patients, 177Lu-PSMA RLT in 154 (32%) patients, and radium-223 dichloride in 18 (4%) patients. The median follow-up duration was 9·0 months (IQR 5·0-17·5). The median overall survival was 15·5 months (95% CI 13·4-18·3) and median progression-free survival was 7·9 months (6·8-8·9). In 347 (71%) of 488 patients, information regarding treatment-induced xerostomia was available, and 236 (68%) of the 347 patients reported xerostomia after the first cycle of 225Ac-PSMA RLT. All patients who received more than seven cycles of 225Ac-PSMA RLT reported xerostomia. Grade 3 or higher anaemia occurred in 64 (13%) of 488 patients, leukopenia in 19 (4%), thrombocytopenia in 32 (7%), and renal toxicity in 22 (5%). No serious adverse events or treatment-related deaths were recorded.

INTERPRETATION

225Ac-PSMA RLT shows a substantial antitumour effect in mCRPC and represents a viable therapy option in patients treated with previous lines of approved agents. Xerostomia is a common side-effect. Severe bone marrow and renal toxicity are less common adverse events.

FUNDING

None.

Survival outcome of chemotherapy-naïve castration-resistant prostate cancer treated with new-generation androgen receptor axis-targeted agents in real-world analysis

PURPOSE

The androgen receptor axis-targeted (ARAT) agents abiraterone and enzalutamide have been introduced against castration-resistant prostate cancer (CRPC). However, determining which of these agents should be used first is a clinical challenge. Therefore, in this study, we compared the efficacy of first-line abiraterone and enzalutamide treatments in chemotherapy-naïve patients with CRPC.

METHODS

A total of 242 chemotherapy-naïve CRPC cases treated with first-line ARAT were analyzed. Outcome measures were PSA response, PSA progression-free survival (PSA-PFS), time to treatment failure (TTF), cancer specific survival (CSS), and overall survival (OS).

RESULTS

Abiraterone (A) and enzalutamide (E) were administered to 61 and 181 patients, respectively. The median PSA response rate (- 65.4% [A] and - 78.8% [E], p = 0.0341), PSA decline ≥ 30% (55.7% [A] and 72.9% [E], p = 0.0183), PSA-PFS (median 4 months [A] and 8 months [E], p = 0.0126), TTF (median 6 months [A] and 14 months [E], p < 0.0001), CSS (median 45 months [A] and not reached [E], p < 0.0001), and OS (median 28 months [A] and 80 months [E], p < 0.001) were significantly better in the enzalutamide group. In the multivariate analyses for CSS and OS, ALP (p = 0.00376) and ARAT (p < 0.001) (CSS), evidence of metastasis (p = 0.0467), Hb (p = 0.00205), and ARAT (p = 0.00514) (OS) were significant factors, respectively.

CONCLUSION

This study showed that PSA response, PSA-PFS, TTF, CSS, and OS were better with first-line enzalutamide administration. Direct inhibition of androgen receptor signaling by enzalutamide is associated with better clinical outcomes.

Novel Therapeutic Targets on the Horizon: An Analysis of Clinical Trials on Therapies for Bone Metastasis in Prostate Cancer

In the absence of early detection and initial treatment, prostate cancer often progresses to an advanced stage, frequently spreading to the bones and significantly impacting patients' well-being and healthcare resources. Therefore, managing patients with prostate cancer that has spread to the bones often involves using bone-targeted medications like bisphosphonates and denosumab to enhance bone structure and minimize skeletal complications. Additionally, researchers are studying the tumor microenvironment and biomarkers to understand the mechanisms and potential treatment targets for bone metastases in prostate cancer. A literature search was conducted to identify clinical studies from 2013 to 2023 that focused on pain, performance status, or quality of life as primary outcomes. The analysis included details such as patient recruitment, prior palliative therapies, baseline characteristics, follow-up, and outcome reporting. The goal was to highlight the advancements and trends in bone metastasis research in prostate cancer over the past decade, with the aim of developing strategies to prevent and treat bone metastases and improve the quality of life and survival rates for prostate cancer patients.

Addressing the risk and management of cardiometabolic complications in prostate cancer patients on androgen deprivation therapy and androgen receptor axis-targeted therapy: consensus statements from the Hong Kong Urological Association and the Hong Kong Society of Uro-Oncology

Background

Androgen deprivation therapy (ADT) is the foundational treatment for metastatic prostate cancer (PCa). Androgen receptor (AR) axis-targeted therapies are a new standard of care for advanced PCa. Although these agents have significantly improved patient survival, the suppression of testosterone is associated with an increased risk of cardiometabolic syndrome. This highlights the urgency of multidisciplinary efforts to address the cardiometabolic risk of anticancer treatment in men with PCa.

Methods

Two professional organizations invited five urologists, five clinical oncologists, and two cardiologists to form a consensus panel. They reviewed the relevant literature obtained by searching PubMed for the publication period from April 2013 to April 2023, to address three discussion areas: (i) baseline assessment and screening for risk factors in PCa patients before the initiation of ADT and AR axis-targeted therapies; (ii) follow-up and management of cardiometabolic complications; and (iii) selection of ADT agents among high-risk patients. The panel convened four meetings to discuss and draft consensus statements using a modified Delphi method. Each drafted statement was anonymously voted on by every panelist.

Results

The panel reached a consensus on 18 statements based on recent evidence and expert insights.

Conclusion

These consensus statements serve as a practical recommendation for clinicians in Hong Kong, and possibly the Asia-Pacific region, in the management of cardiometabolic toxicities of ADT or AR axis-targeted therapies in men with PCa.

Prostate Cancer Liver Metastasis: An Ominous Metastatic Site in Need of Distinct Management Strategies

Prostate cancer liver metastasis (PCLM), seen in upwards of 25% of metastatic castration-resistant PC (mCRPC) patients, is the most lethal site of mCRPC with a median overall survival of 10-14 months. Despite its ominous prognosis and anticipated rise in incidence due to longer survival with contemporary therapy, PCLM is understudied. This review aims to summarize the existing literature regarding the risk factors associated with the development of PCLM, and to identify areas warranting further research. A literature search was conducted through Ovid MEDLINE from 2000 to March 2023. Relevant subject headings and text words were used to capture the following concepts: "Prostatic Neoplasms", "Liver Neoplasms", and "Neoplasm Metastasis". Citation searching identified additional manuscripts. Forty-one studies were retained for detailed analysis. The clinical risk factors for visceral/liver metastasis included <70 years, ≥T3 tumor, N1 nodal stage, de novo metastasis, PSA >20 ng/mL, and a Gleason score >8. Additional risk factors comprised elevated serum AST, LDH or ALP, decreased Hb, genetic markers like RB1 and PTEN loss, PIK3CB and MYC amplification, as well as numerous PC treatments either acting directly or indirectly through inducing liver injury. Further research regarding predictive factors, early detection strategies, and targeted therapies for PCLM are critical for improving patient outcomes.

Enzalutamide versus Abiraterone Plus Prednisolone for Nonmetastatic Castration-Resistant Prostate Cancer: A Sub-Analysis from the ENABLE Study for PCa

Enzalutamide (ENZ) and abiraterone plus prednisolone (ABI) can improve the survival of patients with castration-resistant prostate cancer (CRPC). However, the agent that is more effective against nonmetastatic CRPC remains unclear. To evaluate the agent that can be used as the first-line treatment for CRPC, an investigator-initiated, multicenter, randomized controlled trial (ENABLE Study for PCa) including both metastatic and nonmetastatic CRPC was conducted in Japan. The prostate-specific antigen (PSA) response rate, overall survival, some essential survival endpoints, and safety of patients with nonmetastatic CRPC were also analyzed. In this subanalysis, 15 and 26 patients in the ENZ and ABI arms, respectively, presented with nonmetastatic CRPC. There was no significant difference in terms of the PSA response rate between the ENZ and ABI arms (80% and 64%, respectively; p = 0.3048). The overall survival did not significantly differ between the two arms (HR: 0.68; 95% CI: 0.22-2.14, p = 0.5260). No significant differences were observed in terms of radiographic progression-free survival and cancer-specific survival between the ENZ and ABI arms (HR: 0.81; 95% CI: 0.35-1.84; p = 0.6056 and HR: 0.72; 95% CI: 0.19-2.73; p = 0.6443, respectively). Only four and six patients in the ENZ and ABI arms, respectively, had ≥grade 3 adverse events. ABI and ENZ had similar efficacy and safety profiles in patients with nonmetastatic CRPC.

A phase II study evaluating the efficacy of enzalutamide and the role of liquid biopsy for evaluation of ARv7 in mCRPC patients with measurable metastases including visceral disease (Excalibur study)

Background

Up to 30% of patients with metastatic castration-resistant prostate cancer (mCRPC) develop visceral metastases, which are associated with a poor prognosis.

Objectives

Efficacy of enzalutamide in mCRPC patients with measurable metastases, including visceral and/or extra-regional lymph nodes.

Methods

In this phase II multicenter study, patients with mCRPC and measurable metastases received enzalutamide as the first line. Primary endpoint: 3-month (mo) disease control rate (DCR) defined as the proportion of patients with complete (CR) or partial response (PR) or stable disease (SD) as per Response Evaluation Criteria in Solid Tumors 1.1. Secondary endpoint: safety. Exploratory endpoint: the association between ARv7 splicing variants in basal circulating tumor cell (CTC)-enriched blood samples and treatment response/resistance using the AdnaTest ProstateCancerSelect kit and the AdnaTest ProstateCancer Panel AR-V7.

Results

From March 2017 to January 2021, 68 patients were enrolled. One patient never started treatment. Median age: 72 years. A total of 52 patients (78%) received enzalutamide as a first line for mCRPC. The median follow-up was 32 months. At the 3-month assessment, 24 patients presented an SD, 1 patient achieved a CR, and 23 patients had a PR (3-mo-DCR of 72%). Discontinuations due to adverse events (AEs), disease-related death, or disease progression occurred in 9%, 6%, and 48% of patients. All patients reported at least one grade (G) 1-2 AE: the most common were fatigue (49%) and hypertension (33%). Six G3 AEs were reported: two hypertension, one seizure, one fatigue, one diarrhea, and one headache. Basal detection of ARv7 was significantly associated with poor treatment response (p = 0.034) and a nonsignificant association (p = 0.15) was observed between ARv7 detection and response assessments. At month 3, ARv7 was detected in 57%, 25%, and 15% of patients undergoing progressive disease, SD, and PR, respectively.

Conclusion

The study met its primary endpoint, showing the efficacy of enzalutamide in men with mCRPC and measurable metastatic lesions in visceral and/or lymph node sites.

Trial registration

ClinicalTrials.gov Identifier: NCT03103724. First Posted: 6 April 2017. First patient enrollment: 19 April 2017.

ID2 Promotes Lineage Transition of Prostate Cancer through FGFR and JAK-STAT Signaling

The use of androgen receptor pathway inhibitors (ARPIs) has led to an increase in the proportion of AR-null prostate cancer, including neuroendocrine prostate cancer (NEPC) and double-negative prostate cancer (DNPC), but the mechanism underlying this lineage transition has not been elucidated. We found that ID2 expression was increased in AR-null prostate cancer. In vitro and in vivo studies confirmed that ID2 promotes PCa malignancy and can confer resistance to enzalutamide in PCa cells. We generated an ID2 UP50 signature, which is capable of determining resistance to enzalutamide and is valuable for predicting patient prognosis. Functional experiments showed that ID2 could activate stemness-associated JAK/STAT and FGFR signaling while inhibiting the AR signaling pathway. Our study indicates a potentially strong association between ID2 and the acquisition of a stem-like phenotype in adenocarcinoma cells, leading to resistance to androgen deprivation therapy (ADT) and next-generation ARPIs in prostate cancer.

Gαi2 Protein Inhibition Blocks Chemotherapy- and Anti-Androgen-Induced Prostate Cancer Cell Migration

We have previously shown that heterotrimeric G-protein subunit alphai2 (Gαi2) is essential for cell migration and invasion in prostate, ovarian and breast cancer cells, and novel small molecule inhibitors targeting Gαi2 block its effects on migratory and invasive behavior. In this study, we have identified potent, metabolically stable, second generation Gαi2 inhibitors which inhibit cell migration in prostate cancer cells. Recent studies have shown that chemotherapy can induce the cancer cells to migrate to distant sites to form metastases. In the present study, we determined the effects of taxanes (docetaxel), anti-androgens (enzalutamide and bicalutamide) and histone deacetylase (HDAC) inhibitors (SAHA and SBI-I-19) on cell migration in prostate cancer cells. All treatments induced cell migration, and simultaneous treatments with new Gαi2 inhibitors blocked their effects on cell migration. We concluded that a combination treatment of Gαi2 inhibitors and chemotherapy could blunt the capability of cancer cells to migrate and form metastases.

Mechanism-centric regulatory network identifies NME2 and MYC programs as markers of Enzalutamide resistance in CRPC

Heterogeneous response to Enzalutamide, a second-generation androgen receptor signaling inhibitor, is a central problem in castration-resistant prostate cancer (CRPC) management. Genome-wide systems investigation of mechanisms that govern Enzalutamide resistance promise to elucidate markers of heterogeneous treatment response and salvage therapies for CRPC patients. Focusing on the de novo role of MYC as a marker of Enzalutamide resistance, here we reconstruct a CRPC-specific mechanism-centric regulatory network, connecting molecular pathways with their upstream transcriptional regulatory programs. Mining this network with signatures of Enzalutamide response identifies NME2 as an upstream regulatory partner of MYC in CRPC and demonstrates that NME2-MYC increased activities can predict patients at risk of resistance to Enzalutamide, independent of co-variates. Furthermore, our experimental investigations demonstrate that targeting MYC and its partner NME2 is beneficial in Enzalutamide-resistant conditions and could provide an effective strategy for patients at risk of Enzalutamide resistance and/or for patients who failed Enzalutamide treatment.

Cancer Stem Cells and Treatment of Cancer: An Update and Future Perspectives

Cancer stem cells (CSCs) play an essential role in tumour progression and metastasis. Stem cell ability of self-renewal enables it to persist over time, thereby contributing to cancer relapse or recurrence and also resistance to current therapies. Therefore, targeting CSCs emerged as a promising strategy of cancer treatment. CSCs exhibit differentiation, self-renewal, and plasticity, they contribute to formation of malignant tumours, also favors, metastasis, heterogeneity, multidrug resistance, and radiation resistance. Coventional cancer treatments predominantly target cancer cells that are not CSCs, CSCs frequently survive, eventually leading to relapse. This article focuses on the development of novel therapeutic strategies that combine conventional treatments and CSC inhibitors to eradicate cancer cells and CSCs, for the better and permanent treatment. However, the diversity of CSCs is a significant obstacle in the development of CSC-targeted therapies, necessitating extensive research for a better understanding and exploration of therapeutic approaches. Future development of CSC-targeted therapies will rely heavily on overcoming this obstacle.

Phase 1b study of enzalutamide plus CC-115, a dual mTORC1/2 and DNA-PK inhibitor, in men with metastatic castration-resistant prostate cancer (mCRPC)

BACKGROUND

CC-115, a dual mTORC1/2 and DNA-PK inhibitor, has promising antitumour activity when combined with androgen receptor (AR) inhibition in pre-clinical models.

METHODS

Phase 1b multicentre trial evaluating enzalutamide with escalating doses of CC-115 in AR inhibitor-naive mCRPC patients (n = 41). Primary endpoints were safety and RP2D. Secondary endpoints included PSA response, time-to-PSA progression, and radiographic progression.

RESULTS

Common adverse effects included rash (31.7% Grades 1-2 (Gr); 31.7% Gr 3), pruritis (43.9% Gr 1-2), diarrhoea (37% Gr 1-2), and hypertension (17% Gr 1-2; 9.8% Gr 3). CC-115 RP2D was 5 mg twice a day. In 40 evaluable patients, 80% achieved ≥50% reduction in PSA (PSA50), and 58% achieved ≥90% reduction in PSA (PSA90) by 12 weeks. Median time-to-PSA progression was 14.7 months and median rPFS was 22.1 months. Stratification by PI3K alterations demonstrated a non-statistically significant trend towards improved PSA50 response (PSA50 of 94% vs. 67%, p = 0.08). Exploratory pre-clinical analysis suggested CC-115 inhibited mTOR pathway strongly, but may be insufficient to inhibit DNA-PK at RP2D.

CONCLUSIONS

The combination of enzalutamide and CC-115 was well tolerated. A non-statistically significant trend towards improved PSA response was observed in patients harbouring PI3K pathway alterations, suggesting potential predictive biomarkers of response to a PI3K/AKT/mTOR pathway inhibitor.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02833883.

UBE2J1 is the E2 ubiquitin-conjugating enzyme regulating androgen receptor degradation and antiandrogen resistance

Prostate cancer (PCa) is primarily driven by aberrant Androgen Receptor (AR) signaling. Although there has been substantial advancement in antiandrogen therapies, resistance to these treatments remains a significant obstacle, often marked by continuous or enhanced AR signaling in resistant tumors. While the dysregulation of the ubiquitination-based protein degradation process is instrumental in the accumulation of oncogenic proteins, including AR, the molecular mechanism of ubiquitination-driven AR degradation remains largely undefined. We identified UBE2J1 as the critical E2 ubiquitin-conjugating enzyme responsible for guiding AR ubiquitination and eventual degradation. The absence of UBE2J1, found in 5-15% of PCa patients, results in disrupted AR ubiquitination and degradation. This disruption leads to an accumulation of AR proteins, promoting resistance to antiandrogen treatments. By employing a ubiquitination-based AR degrader to adeptly restore AR ubiquitination, we reestablished AR degradation and inhibited the proliferation of antiandrogen-resistant PCa tumors. These findings underscore the fundamental role of UBE2J1 in AR degradation and illuminate an uncharted mechanism through which PCa maintains heightened AR protein levels, fostering resistance to antiandrogen therapies.

Concomitant antihypertensive medication and outcome of patients with metastatic castration-resistant prostate cancer receiving enzalutamide or abiraterone acetate

BACKGROUND

The introduction of novel hormonal therapies represented by enzalutamide (ENZ) and abiraterone acetate (ABI) has reached a great progress in the treatment of metastatic castration-resistant prostate cancer (mCRPC). The majority of mCRPC patients are elderly suffering from chronic co-morbidities requiring use of various concomitant medications. In the present study, we focused on impact of concomitant antihypertensive medication on the outcomes of mCRPC patients treated with ENZ or ABI.

METHODS

In total, 300 patients were included and their clinical data were retrospectively analyzed.

RESULTS

Angiotensin-converting enzyme inhibitors (ACEIs) represented the only concomitant medication significantly associated with survival. The median radiographic progression-free survival (rPFS) and overall survival (OS) for patients using ACEIs were 15.5 and 32.3 months compared to 10.7 and 24.0 months for those not using ACEIs (p = 0.0053 and p = 0.0238, respectively). Cox multivariable analysis revealed the use of ACEIs a significant predictive factor for both rPFS (HR = 0.704, p = 0.0364) and OS (HR = 0.592, p = 0.0185).

CONCLUSION

The findings of this study suggest an association between the concomitant use of ACEIs and longer survival of mCRPC patients receiving ENZ or ABI therapy.

Long-Term Efficacy and Safety of Enzalutamide Monotherapy in Elderly Patients with Metastatic Castration-Resistant Prostate Cancer: A Case Report

Introduction

Prostate cancer is one of the most common cancers in men. Despite the sharp rise in incidence, mortality is decreasing. ARTA preparations are preferred options for asymptomatic or mildly symptomatic patients with mCRPC. The use of enzalutamide in elderly patients with mCRPC is risky and depends on a number of factors. An increased risk of falls and fractures has been shown.

Case Presentation

We present a case report of an elderly patient with mCRPC treated with enzalutamide with very good long-term tolerance and efficacy.

Conclusion

Despite the older age, no reduction of therapy was necessary in the patient due to good tolerance. Administration of enzalutamide in full doses resulted in a very good effect of therapy.

Management of Advanced Prostate Cancer With Relugolix: Illustrative Case Scenarios From an Advanced Practice Provider Perspective

Prostate cancer is the second most common cause of cancer-related mortality among men in the United States, with an estimated 34,700 deaths annually. Androgen deprivation therapy (ADT) is the cornerstone of advanced prostate cancer therapy, and injectable luteinizing hormone-releasing hormone (LHRH) agonists have served as the most commonly used ADT for over 30 years. Relugolix, a first-in-class, once-daily, oral gonadotropin-releasing hormone (GnRH) antagonist, was developed to address some of the limitations of available ADT therapies. Herein, we present two hypothetical case reports via an advanced practice provider (APP) perspective that reflect prototypical examples of patients with advanced localized disease not suitable for surgery or newly diagnosed hormone-sensitive metastatic disease treated with relugolix. The cases presented are meant to be instructional and within the scope of the current approved prescribing information for all medications mentioned. Best practices from an APP perspective are shared.

Newly developed preclinical models reveal broad-spectrum CDK inhibitors as potent drugs for CRPC exhibiting primary resistance to enzalutamide

Androgen-deprivation therapy is a standard treatment for advanced prostate cancer. However, most patients eventually acquire resistance and progress to castration-resistant prostate cancer (CRPC). In this study, we established new CRPC cell lines, AILNCaP14 and AILNCaP15, from LNCaP cells under androgen-deprived conditions. Unlike most pre-existing CRPC cell lines, both cell lines expressed higher levels of androgen receptor (AR) and prostate-specific antigen (PSA) than parental LNCaP cells. Moreover, these cells exhibited primary resistance to enzalutamide. Since AR signaling plays a significant role in the development of CRPC, PSA promoter sequences fused with GFP were introduced into AILNCaP14 cells to conduct GFP fluorescence-based chemical screening. We identified flavopiridol, a broad-spectrum CDK inhibitor, as a candidate drug that could repress AR transactivation of CRPC cells, presumably through the inhibition of phosphorylation of AR on the serine 81 residue (pARSer81 ). Importantly, this broad-spectrum CDK inhibitor inhibited the proliferation of AILNCaP14 cells both in vitro and in vivo. Moreover, a newly developed liver metastatic model using AILNCaP15 cells revealed that the compound attenuated tumor growth of CRPC harboring highly metastatic properties. Finally, we developed a patient-derived xenograft (PDX) model of CRPC and DCaP CR from a patient presenting therapeutic resistance to enzalutamide, abiraterone, and docetaxel. Flavopiridol successfully suppressed the tumor growth of CRPC in this PDX model. Since ARSer81 was found to be phosphorylated in clinical CRPC samples, our data suggested that broad-spectrum CDK inhibitors might be a potent candidate drug for the treatment of CRPC, including those exhibiting primary resistance to enzalutamide.

A common germline variant in CYP11B1 is associated with adverse clinical outcome of treatment with abiraterone or enzalutamide

Extragonadal androgens play a pivotal role in prostate cancer disease progression on androgen receptor signaling inhibitors (ARSi), including abiraterone and enzalutamide. We aimed to investigate if germline variants in genes involved in extragonadal androgen synthesis contribute to resistance to ARSi and may predict clinical outcomes on ARSi. We included ARSi naive metastatic prostate cancer patients treated with abiraterone or enzalutamide and determined 18 germline variants in six genes involved in extragonadal androgen synthesis. Variants were tested in univariate and multivariable analysis for the relation with overall survival (OS) and time to progression (TTP) by Cox regression, and PSA response by logistic regression. A total of 275 patients were included. From the investigated genes CYP17A1, HSD3B1, CYP11B1, AKR1C3, SRD5A1 and SRD5A2, only rs4736349 in CYP11B1 in homozygous form (TT), present in 54 patients (20%), was related with a significantly worse OS (HR = 1.71, 95% CI 1.09 - 2.68, p = 0.019) and TTP (HR = 1.50, 95% CI 1.08 - 2.09, p = 0.016), and was related with a significantly less frequent PSA response (OR = 0.48, 95% CI 0.24 - 0.96, p = 0.038) on abiraterone or enzalutamide in a multivariable analysis. The frequent germline variant rs4736349 in CYP11B1 is, as homozygote, an independent negative prognostic factor for treatment with abiraterone or enzalutamide in ARSi naive metastatic prostate cancer patients. Our findings warrant prospective investigation of this potentially important predictive biomarker.

Stereotactic Body Radiation Therapy and Abiraterone Acetate for Patients Affected by Oligometastatic Castrate-Resistant Prostate Cancer: A Randomized Phase II Trial (ARTO)

PURPOSE

ARTO (ClinicalTrials.gov identifier: NCT03449719) is a multicenter, phase II randomized clinical trial testing the benefit of adding stereotactic body radiation therapy (SBRT) to abiraterone acetate and prednisone (AAP) in patients with oligometastatic castrate-resistant prostate cancer (CRPC).

MATERIALS AND METHODS

All patients were affected by oligometastatic CRPC as defined as three or less nonvisceral metastatic lesions. Patients were randomly assigned 1:1 to receive either AAP alone (control arm) or AAP with concomitant SBRT to all the sites of disease (experimental arm). Primary end point was the rate of biochemical response (BR), defined as a prostate-specific antigen (PSA) decrease ≥50% from baseline measured at 6 months from treatment start. Complete BR (CBR), defined as PSA < 0.2 ng/mL at 6 months from treatment, and progression-free survival (PFS) were secondary end points.

RESULTS

One hundred and fifty-seven patients were enrolled between January 2019 and September 2022. BR was detected in 79.6% of patients (92% v 68.3% in the experimental v control arm, respectively), with an odds ratio (OR) of 5.34 (95% CI, 2.05 to 13.88; P = .001) in favor of the experimental arm. CBR was detected in 38.8% of patients (56% v 23.2% in the experimental v control arm, respectively), with an OR of 4.22 (95% CI, 2.12 to 8.38; P < .001). SBRT yielded a significant PFS improvement, with a hazard ratio for progression of 0.35 (95% CI, 0.21 to 0.57; P < .001) in the experimental versus control arm.

CONCLUSION

The trial reached its primary end point of biochemical control and PFS, suggesting a clinical advantage for SBRT in addition to first-line AAP treatment in patients with metastatic castration-resistant prostate cancer.

Synthetic Lethality by Co-Inhibition of Androgen Receptor and Polyadenosine Diphosphate-Ribose in Metastatic Prostate Cancer

Androgen receptor pathway inhibitors (ARPI) and polyadenosine diphosphate-ribose inhibitors (PARPi) are part of the standard of care in patients with metastatic castration-resistant prostate cancer (mCRPC). There is biological evidence that the association of ARPI and PARPi could have a synergistic effect; therefore, several ongoing clinical trials are investigating the efficacy of this combination with preliminary results that are not perfectly concordant in identifying patients who can obtain the most benefit from this therapeutic option. The purpose of this review is to describe the PARPi mechanisms of action and to analyze the biological mechanisms behind the interplay between the androgen receptor and the PARPi system to better understand the rationale of the ARPI + PARPi combinations. Furthermore, we will summarize the preliminary results of the ongoing studies on these combinations, trying to understand in which patients to apply. Finally, we will discuss the clinical implications of this combination and its possible future perspectives.

Time trends in systemic treatment for patients with metastatic prostate cancer: a national cohort study

BACKGROUND

Several new systemic treatments for primary metastatic prostate cancer patients (mPCa) were introduced in the last decade for both hormone-sensitive (mHSPC) and castration-resistant prostate cancer (mCRPC). However, little is known about the introduction of these treatments in clinical practice. In this national cohort study, we described users and non-users of systemic treatment beyond androgen deprivation therapy (ADT). We also explored whether there was a shift in treatment patterns after the introduction of Docetaxel for mHSPC patients.

MATERIALS AND METHODS

All patients registered in the Cancer Registry of Norway with mPCa diagnosed in 2010-18 were included. Data on systemic therapy (Docetaxel, Abiraterone, Enzalutamide, Cabazitaxel, and Radium-223) were provided from the Norwegian Prescription Database, the Norwegian Patient Registry, and the Norwegian Control and Payment of Health Reimbursement Database. Descriptive results about patient and disease characteristics were presented using frequencies and proportions, means and standard deviations, or medians and interquartile ranges.

RESULTS

Of the 2770 patients included in this study, 48% received systemic treatment beyond ADT. The proportion of patients receiving systemic treatment increased during the study period. Systemic treatment users were younger, in better general condition, and had more aggressive tumors than non-users. A treatment shift was observed after 2015, with 48% of patients receiving systemic treatment (mainly Docetaxel) in the mHSPC phase compared to 4% of those diagnosed 2010-14. No significant treatment differences were observed across health regions.

CONCLUSIONS

An increasing proportion of patients received systemic treatment during the period 2010-18. However, less than 50% of patients in our study received systemic treatment. In accordance with updated guidelines, Docetaxel was introduced after 2015 with an increasing proportion of patients receiving systemic treatment as mHSPC. Further studies should address the disease course and treatment given to patients who do not receive systemic treatment.

Progression-free survival, disease-free survival and other composite end points in oncology: improved reporting is needed

Composite outcome measures such as progression-free survival and disease-free survival are increasingly used as surrogate end points in oncology research, frequently serving as the primary end point of pivotal trials that form the basis for FDA and EMA approvals. Such outcome measures combine two or more distinct events (for example, tumour (re)growth, new lesions and/or death) into a single, time-to-event end point. The use of a composite end point can increase the statistical power of a clinical trial and decrease the follow-up period required to demonstrate efficacy, thus lowering costs; however, these end points have a number of limitations. Composite outcomes are often vaguely defined, with definitions that vary greatly between studies, complicating comparisons of results across trials. Altering the makeup of events included in a composite outcome can alter study conclusions, including whether treatment effects are statistically significant. Moreover, the events included in a composite outcome often vary in clinical significance, reflect distinct biological pathways and/or are affected differently by treatment. Therefore, knowing the precise breakdown of the component events is essential to accurately interpret trial results and gauge the true benefit of an intervention. In oncology clinical trials, however, such information is rarely provided. In this Perspective, we emphasize this deficiency through a review of 50 studies with progression-free survival as an outcome published in five top oncology journals, discuss the advantages and challenges of using composite end points, and highlight the need for transparent reporting of the component events.

Advances in non-radioactive PSMA-targeted small molecule-drug conjugates in the treatment of prostate cancer

Most patients with advanced prostate cancer (PCa) will develop metastatic castration-resistant prostate cancer (mCRPC) after androgen deprivation therapy, at this time the tumor enters the end stage, and the clinical treatment is very complicated, which requires rationalization of drugs to prolong the life of patients while improving their quality of life. Prostate-specific membrane antigen (PSMA) is a promising biological target for drug delivery in mCRPC due to its high level of specific expression in PCa cell membranes and low expression in normal tissues. Non-radioactive PSMA-targeted small molecule-drug conjugates (SMDCs) are gradually becoming a heat of discovery due to their good affinity and specificity; simple synthesis steps and transport management methods. Non-radioactive PSMA-targeted SMDCs under investigation can be divided into two categories: SMDCs and dual-ligand coupled drugs, among which SMDCs are the most widespread form of this type of conjugate. SMDCs have three key components: cytotoxic load, linker, and small molecule targeting ligands. SMDCs are internalized into the cell after binding to PSMA on the cell membrane and stored in endosomes and lysosomes, where they are usually enzymatically cleaved to allow precise release of cytotoxic molecules and uniform diffusion into the tumor tissue. More than a dozen non-radioactive PSMA-targeted SMDCs have been developed, many of which have shown favorable properties in both in vitro and in vivo evaluations, demonstrating more favorable results than unmodified cytotoxic drugs. Therefore, non-radioactive PSMA-targeted SMDCs have great therapeutic potential for mCRPC as a form of targeted therapy.

Characterization of prostate cancer adrenal metastases: dependence upon androgen receptor signaling and steroid hormones

BACKGROUND

Prostate cancer (PCa) typically spreads to the bone, and this distribution is attributed to the central role of the microenvironment in progression. However, metastasis to the adrenal glands, while not as common, does occur. The biology that accounts for adrenal metastases may be attributed to the unique local steroid metabolome and co-clinical characterization may elucidate the role steroid biosynthesis plays in PCa progression.

METHODS

Three patients with metastatic PCa who had archived tumor tissue from an adrenalectomy were retrospectively identified, and one adrenal metastasis was developed into a xenograft (MDA-PCa-250). The adrenal metastases were characterized by performing somatic DNA whole exome sequencing (WES), RNA-Seq, immunohistochemistry (IHC), and steroid metabolite quantitation. The influence of steroid metabolites on adrenal metastasis cells and tumor growth was tested in vitro and in vivo.

RESULTS

Clinically, adrenalectomy was performed during castration-resistant oligometastatic disease, and two men experienced resensitization to leuprolide. Somatic DNA WES revealed heterogeneous alterations in tumor suppressor and DNA damage repair pathway genes. Adrenal metastases had active androgen receptor (AR) signaling by IHC, and RNA-Seq supported a potential role for adrenal androgen precursor metabolism in activating the AR. Steroid quantitation suggested the adrenal androgen precursors were converted into testosterone in these metastases, and stable isotope tracing of an organoid from MDA-PCa-250 confirmed the capability of adrenal metastases to biosynthesize testosterone from adrenal precursors. In vitro testing of a cell line derived from MDA-PCa-250 showed that testosterone and cortisol stimulated tumor cell growth. In vivo experiments demonstrated that MDA-PCa-250 grew in intact mice with circulating testosterone, but not in castrated mice.

CONCLUSIONS

PCa adrenal metastases depend upon AR signaling driven by androgen precursors, androstenedione and dehydroepiandrosterone, available in the microenvironment, despite the presence of heterogeneous somatic DNA alterations. Moreover, MDA-PCa-250 provides a preclinical model that can recapitulate the unique androgen-dependence of adrenal metastases.

CLINICAL TRIAL REGISTRATION

This study does not report the clinical results of a clinical trial, but it does use samples from a completed clinical trial that is registered with clinicaltrials.gov (NCT01254864).

[Role of chemotherapy in metastatic castration-resistant prostate cancer (mCRPC) treatment: still standard or exception?]

BACKGROUND

Taxanes have been used as monotherapy for metastatic prostate cancer for two decades.

OBJECTIVES

The current status of docetaxel and cabazitaxel in the treatment sequence for metastatic prostate cancer needs to be clarified.

MATERIALS AND METHODS

Overview of the existing literature regarding approval, dosage and new combination options for metastatic castration-resistant prostate cancer (mCRPC).

RESULTS

Taxanes represent one, but no longer the only treatment option for mCRPC. Previously, monotherapy was standard of care in the first and second line for mCRPC; nowadays taxanes are thrusted in the background due to new encouraging drug options. Based on the promising data of docetaxel in triple therapy setting for hormone-sensitive stage, its role as monotherapy in mCRPC needs to be clarified. Cabazitaxel is an alternative to PSMA radioligand therapy after failure of novel hormonal therapy (NHT) and docetaxel. Therapy adherence for taxanes can be significantly improved by dosage adjustments. Both treatment-related neuroendocrine prostate cancer (t-NEPC) and aggressive variant of prostate cancer (AVPC) represent a challenge for experienced uro-oncologists. Here, the combination of taxane plus platinum represents a promising option.

CONCLUSIONS

Taxanes are indicated in different stages of metastatic prostate cancer. Their use, particularly in combination with other drugs, appears to be promising. Traditional sequential taxane monotherapy regimens will be challenged by novel systemic therapy approaches.

[Metastatic castration-resistant prostate cancer-what are rational sequential treatment options?]

BACKGROUND

In advanced prostate cancer, disease progression during ongoing androgen deprivation therapy (ADT) is referred to as castration-resistant prostate cancer (CRPC). Various therapeutic modalities are available for its treatment, including endocrine therapy, chemotherapy, poly (ADP-ribose) polymerase [PARP] inhibition, radionuclide therapy, and radioligand therapy.

OBJECTIVES

This review outlines practical aspects and considerations regarding treatment sequencing in mCRPC.

MATERIALS AND METHODS

The findings are based on existing prospective phase 3 studies that have demonstrated clinically relevant and statistically significant benefits in radiographically progression-free and/or overall survival.

RESULTS

Sequential therapy, aside from numerous patient-specific factors, depends on the treatment patients received in the hormone-sensitive prostate cancer (mHSPC) setting. Following pretreatment with ADT alone or ADT plus docetaxel in the mHSPC context, additional endocrine therapy is the standard approach. In the event of progression under combined endocrine therapy initiated in the mHSPC setting, docetaxel currently serves as the standard for the majority of patients. Patients who received triplet therapy as a pretreatment in the mHSPC scenario can be treated with radioligand therapy or second-line chemotherapy.

CONCLUSION

Various active and well-tolerated treatment options are available for patients with metastatic castration-resistant prostate cancer (mCRPC). The choice of therapy is primarily determined by previous treatments, but many other individual factors are also taken into consideration.

Genomic and epigenomic analysis of plasma cell-free DNA identifies stemness features associated with worse survival in AR -altered lethal prostate cancer

Metastatic castration-resistant prostate cancer (mCRPC) resistant to androgen receptor (AR)-targeted agents is often lethal. Unfortunately, biomarkers for this deadly disease remain under investigation, and underpinning mechanisms are ill-understood. Here, we applied deep sequencing to ∼100 mCRPC patients prior to the initiation of first-line AR-targeted therapy, which detected AR /enhancer alterations in over a third of patients, which correlated with lethality. To delve into the mechanism underlying why these patients with cell-free AR /enhancer alterations developed more lethal prostate cancer, we next performed genome-wide cell-free DNA epigenomics. Strikingly, we found that binding sites for transcription factors associated with developmental stemness were nucleosomally more accessible. These results were corroborated using cell-free DNA methylation data, as well as tumor RNA sequencing from a held-out cohort of mCRPC patients. Thus, we validated the importance of AR /enhancer alterations as a prognostic biomarker in lethal mCRPC, and showed that the underlying mechanism for lethality involves reprogramming developmental states toward increased stemness.

Catalytic Enantioselective Biltz Synthesis

The Biltz synthesis establishes straightforward access to 5,5-disubstituted (thio)hydantoins by combining a 1,2-diketone and a (thio)urea. Its appealing features include inherent atom and step economy together with the potential to generate structurally diverse products. However, control of the stereochemistry of this reaction has proven to be a daunting challenge. Herein, we describe the first example of enantioselective catalytic Biltz synthesis which affords more than 40 thiohydantoins with high stereo- and regio-control, irrespective of the symmetry of thiourea structure. A one pot synthesis of corresponding hydantoins is also documented. Remarkably, experimental studies and DFT calculations establish the reaction pathway and origin of stereoselectivity.

Precision strikes: PSMA-targeted radionuclide therapy in prostate cancer - a narrative review

Introduction

Radio-ligand targeted therapy is a new and promising concept of treatment Castration resistant prostate cancer (CRPC). Only a few radio-pharmaceutics were approved for usage in treating prostate cancer, among the multiple others tested. We aimed to review and summarize the literature on the therapeutic isotopes specific for PSMA.

Methods

We performed a scoping literature review of PubMed from January 1996 to December 2022.

Results

98 publications were selected for inclusion in this review. The studies contained in publications allowed to summarize the data on pharmacokinetics, therapeutic effects, side effects and the medical use of 225Ac and 177Lu radionuclides. The review also presents new research directions for specific PSMA radionuclides.

Conclusion

Radioligand targeted therapy is a new and promising concept where Lu-177-PSMA-617 have promising outcomes in treatment according to standard of care.

Targeting DNA methylation and B7-H3 in RB1-deficient and neuroendocrine prostate cancer

Aberrant DNA methylation has been implicated as a key driver of prostate cancer lineage plasticity and histologic transformation to neuroendocrine prostate cancer (NEPC). DNA methyltransferases (DNMTs) are highly expressed, and global DNA methylation is dysregulated in NEPC. We identified that deletion of DNMT genes decreases expression of neuroendocrine lineage markers and substantially reduced NEPC tumor development and metastasis in vivo. Decitabine, a pan-DNMT inhibitor, attenuated tumor growth in NEPC patient-derived xenograft models, as well as retinoblastoma gene (RB1)-deficient castration-resistant prostate adenocarcinoma (CRPC) models compared with RB1-proficient CRPC. We further found that DNMT inhibition increased expression of B7 homolog 3 (B7-H3), an emerging druggable target, via demethylation of B7-H3. We tested DS-7300a (i-DXd), an antibody-drug conjugate targeting B7-H3, alone and in combination with decitabine in models of advanced prostate cancer. There was potent single-agent antitumor activity of DS-7300a in both CRPC and NEPC bearing high expression of B7-H3. In B7-H3-low models, combination therapy of decitabine plus DS-7300a resulted in enhanced response. DNMT inhibition may therefore be a promising therapeutic target for NEPC and RB1-deficient CRPC and may sensitize B7-H3-low prostate cancer to DS-7300a through increasing target expression. NEPC and RB1-deficient CRPC represent prostate cancer subgroups with poor prognosis, and the development of biomarker-driven therapeutic strategies for these populations may ultimately help improve patient outcomes.

Discovery of potent pyrrolo-pyrimidine and purine HDAC inhibitors for the treatment of advanced prostate cancer

The development of drugs for the treatment of advanced prostate cancer (PCA) remains a challenging task. In this study we have designed, synthesized and tested twenty-nine novel HDAC inhibitors based on three different zinc binding groups (trifluoromethyloxadiazole, hydroxamic acid, and 2-mercaptoacetamide). These warheads were conveniently tethered to variously substituted phenyl linkers and decorated with differently substituted pyrrolo-pyrimidine and purine cap groups. Remarkably, most of the compounds showed nanomolar inhibitory activity against HDAC6. To provide structural insights into the Structure-Activity Relationships (SAR) of the investigated compounds, docking of representative inhibitors and molecular dynamics of HDAC6-inhibitor complexes were performed. Compounds of the trifluoromethyloxadiazole and hydroxamic acid series exhibited promising anti-proliferative activities, HDAC6 targeting in PCA cells, and in vitro tumor selectivity. Representative compounds of the two series were tested for solubility, cell permeability and metabolic stability, demonstrating favorable in vitro drug-like properties. The more interesting compounds were subjected to migration assays, which revealed that compound 13 and, to a lesser extent, compound 15 inhibited the invasive behaviour of androgen-sensitive and -insensitive advanced prostate cancer cells. Compound 13 was profiled against all HDACs and found to inhibit all members of class II HDACs (except for HDAC10) and to be selective with respect to class I and class IV HDACs. Overall, compound 13 combines potent inhibitory activity and class II selectivity with favorable drug-like properties, an excellent anti-proliferative activity and marked anti-migration properties on PCA cells, making it an excellent lead candidate for further optimization.

Treatment Landscape for Metastatic Castrate-Sensitive Prostate Cancer: A Review

With the advent of new therapeutic modalities, management of metastatic castrate-sensitive prostate cancer (mCSPC) has been in flux. From androgen-deprivation therapy to docetaxel to androgen receptor-signaling inhibitors, each agent has heralded a new treatment paradigm. As such, the optimal first-line therapy for mCSPC remains incompletely defined. This review provides a narrative of recent advances to systemic therapy within the mCSPC treatment space, particularly with regard to expansion to triplet therapy.

Validation of JSBMR's CTIBL manual for Japanese men receiving androgen deprivation therapy for prostate cancer

INTRODUCTION

Androgen deprivation therapy (ADT) for prostate cancer causes cancer treatment-induced bone loss (CTIBL), increases the fracture risk 2-3 times, and worsens life prognoses. The Japan Society of Bone and Mineral Research (JSBMR) created a CTIBL treatment manual in 2020; however, no study has validated its use in patients with ADT/CTIBL prostate cancer.

MATERIALS AND METHODS

This study classified 124 patients with prostate cancer without bone metastasis who received ADT into high- and low-risk groups using the JSBMR CTIBL algorithm. Comparisons were made with the period to incident vertebral fracture and the existing International Osteoporosis Foundation (IOF) classification.

RESULTS

The median age was 74 years; the median observation period was 81 months. At 1, 3, 5, 7, and 9 years, the prevalence of incident vertebral fractures was, respectively, 3.3%, 10.7%, 17.9%, 21.4%, and 31.2% in the entire population; 13%, 27%, 36%, 42%, and 58% in the high-risk group (19%); and 1%, 7%, 14%, 17%, and 25% in the low-risk group (81%). The hazard ratio between the two groups was 3.57 (p = 0.0004). Based on multivariate analysis, age, previous vertebral fracture and femoral neck bone density were significant risk factors for incidental vertebral fracture. The JSBMR had a hazard ratio of 3.26 (p = 0.04) relative to 1.13 (p = 0.84) for the IOF, indicating the JSBMR classification performed better.

CONCLUSION

Taking preventive measures against fractures is necessary, including starting bone-modifying agents early in patients with a high fracture risk. The JSBMR CTIBL manual may be useful for this purpose.

Updates in the Treatment of Non-Metastatic Castrate-Resistant Prostate Cancer: The Benefit of Second-Generation Androgen Receptor Antagonists

OBJECTIVE

To review pharmacology, efficacy, safety, and considerations for use, of second-generation androgen receptor (AR) antagonists in treatment of nonmetastatic castrate-resistant prostate cancer (M0CRPC).

DATA SOURCES

Conducted search in PubMed and Google scholar (January, 1, 2002-December 31, 2022), using relevant terms.

STUDY SELECTION AND DATA EXTRACTION

Relevant English-language studies, conducted in humans evaluating second-generation AR antagonists for M0CRPC, and additional articles and package inserts were considered.

DATA SYNTHESIS

Apalutamide, darolutamide, and enzalutamide are effective in delaying the time to development of metastatic prostate cancer in men with M0CRPC with a rapid prostate-specific antigen (PSA) doubling time (<10 months). No head-to-head, randomized, clinical trials have been conducted. The most common adverse effects include fatigue and hypertension, and quality of life is maintained in most patients. Cost is similar among the agents (~$15,000/month). Drug-drug interactions vary among these agents and should be considered, when selecting therapy as well as likely adherence. Darolutamide is administered twice daily with the others once daily.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

Second-generation AR antagonists are effective in reducing time to development of metastatic disease and prolonging overall survival in patients with M0CRPC and a PSA doubling time of <10 months. Recent imaging advances may alter how we evaluate outcomes.

CONCLUSIONS

Second-generation AR antagonists improve disease control and overall survival. Generally, they are well tolerated and QOL is maintained. Selection of the best agent is based on the adverse effect profile, potential for drug- and disease-interactions, administration, cost, and patient preference.

Real-world outcomes for first line next-generation hormonal agents in metastatic prostate cancer: a systematic review

Aim: This review aims to summarize published evidence on the real-world (RW) outcomes of abiraterone or enzalutamide in first-line metastatic castration-resistant prostate cancer. Materials & methods: Studies reporting on RW effectiveness, safety, economic and/or health-related quality of life outcomes were identified by systematic literature review (2011-2021, incl. Embase®, MEDLINE®) and presented in a qualitative synthesis. Risk of bias was assessed using ROBINS-I or the Molinier checklist. Results: 88 studies (n = 83,427 patients) were included. Median progression-free (40 studies) and overall survival (38 studies) ranged from 3.7 to 20.9 months and 9.8 to 45 months, respectively. Survival, safety and economic outcomes were similar across individual treatments, while limited health-related quality of life evidence suggested improvements with abiraterone. Risk of bias was moderate to high. Conclusion: RW outcomes in first-line metastatic castration-resistant prostate cancer remain poor despite treatment, highlighting an unmet need for new regimens. This review was supported by AstraZeneca and Merck Sharp & Dohme.

Downregulation of EZH2 inhibits epithelial-mesenchymal transition in enzalutamide-resistant prostate cancer

BACKGROUND

Androgen signaling inhibitors (ASI) have been approved for treatment of metastatic castration-resistant prostate cancer (mCRPC). However, the limited success of ASI in clinic justifies an urgent need to identify new targets and develop novel approaches for treatment. EZH2 significantly increases in prostate cancer (PCa). Little is understood, however, regarding the roles of EZH2 in Enzalutamide-resistant (EnzR) mCRPC.

METHODS

We firstly investigated the levels of EZH2 and the altered pathways in public database which was comprised with primary and metastatic PCa patient tumors. To elucidate the roles of EZH2 in mCRPC, we manipulated EZH2 in EnzR PCa cell lines to examine epithelial-mesenchymal transition (EMT). To dissect the underlying mechanisms, we measured the transcription levels of EMT-associated transcription factors (TFs).

RESULTS

We found that EZH2 was highly expressed in mCRPC than that of primary PCa tumors and that EnzR PCa cells gained more EMT characteristics than those of enzalutamide-sensitive counterparts. Further, loss of EZH2-induced inhibition of EMT is independent of polycomb repressive complex 2 (PRC2). Mechanistically, downregulation of EZH2 inhibits transcription of EMT-associated TFs by repressing formation of H3K4me3 to the promotor regions of the TFs.

CONCLUSION

We identified the novel roles of EZH2 in EnzR mCRPC. EnzR PCa gains more EMT properties than that of enzalutamide-sensitive PCa. Loss of EZH2-assocaited inhibition of EMT is PRC2 independent. Downregulation of EZH2 suppresses EMT by impairing formation of H3K4me3 at the promotor regions, thus repressing expression of EMT-associated TFs.

[Guidelines for Evaluating Treatment Response Based on Bone Scan for Metastatic Castration-Resistant Prostate Cancer: Prostate Cancer Clinical Trial Working Group 3 Recommendations]

In prostate cancer, the bone is the most common site of metastasis, and it is essential to evaluate metastatic bone lesions to assess the tumor burden and treatment response. Castration-resistant prostate cancer refers to the state wherein the cancer continues to progress despite a significant reduction of the sex hormone level and is associated with frequent distant metastasis. The Prostate Cancer Working Group 3 (PCWG3) released guidelines that aimed to standardize the assessment of treatment effects in castration-resistant prostate cancer using bone scintigraphy. However, these guidelines can be challenging to comprehend and implement in practical settings. The purpose of this review was to provide an overview of a specific image acquisition method and treatment response assessment for bone scintigraphy-based evaluation of bone lesions in metastatic castration-resistant prostate cancer, in accordance with the PCWG3 guidelines.

Genomic Profiling of Metastatic Castration-Resistant Prostate Cancer Samples Resistant to Androgen Receptor Pathway Inhibitors

PURPOSE

The androgen receptor axis inhibitors (ARPI; e.g., enzalutamide, abiraterone acetate) are administered in daily practice for men with metastatic castration-resistant prostate cancer (mCRPC). However, not all patients respond, and mechanisms of both primary and acquired resistance remain largely unknown.

EXPERIMENTAL DESIGN

In the prospective trial MATCH-R (NCT02517892), 59 patients with mCRPC underwent whole-exome sequencing (WES) and/or RNA sequencing (RNA-seq) of samples collected before starting ARPI. Also, 18 patients with mCRPC underwent biopsy at time of resistance. The objectives were to identify genomic alterations associated with resistance to ARPIs as well as to describe clonal evolution. Associations of genomic and transcriptomic alterations with primary resistance were determined using Wilcoxon and Fisher exact tests.

RESULTS

WES analysis indicated that no single-gene genomic alterations were strongly associated with primary resistance. RNA-seq analysis showed that androgen receptor (AR) gene alterations and expression levels were similar between responders and nonresponders. RNA-based pathway analysis found that patients with primary resistance had a higher Hedgehog pathway score, a lower AR pathway score and a lower NOTCH pathway score than patients with a response. Subclonal evolution and acquisition of new alterations in AR-related genes or neuroendocrine differentiation are associated with acquired resistance. ARPIs do not induce significant changes in the tumor transcriptome of most patients; however, programs associated with cell proliferation are enriched in resistant samples.

CONCLUSIONS

Low AR activity, activation of stemness programs, and Hedgehog pathway were associated with primary ARPIs' resistance, whereas most acquired resistance was associated with subclonal evolution, AR-related events, and neuroendocrine differentiation. See related commentary by Slovin, p. 4323.

Comparative efficacy of olaparib in combination with or without novel antiandrogens for treating metastatic castration-resistant prostate cancer

Background

Studies using novel antiandrogens (NAA) in patients with metastatic castration-resistant prostate cancer (mCRPC) have shown overall survival benefit. As patients develop resistance to NAA therapy, the poly(ADP-ribose) polymerase inhibitor (PARPi) olaparib in combination with NAA may become a promising therapy. However the overall benefit of olaparib monotherapy or combination therapy still needs to be evaluated. Therefore, we performed a network meta-analysis to assess the efficacy and toxicity between olaparib, olaparib combined with abiraterone and NAA.

Methods

We searched PubMed, EMBASE, the Cochrane Library and American Society of Clinical Oncology (ASCO) University Meeting abstracts for randomized controlled trials reporting olaparib and NAA from 2010 up to March, 2023. Network meta-analysis using Stata 16.0 and R 4.4.2, hazard ratios (HR) with 95% confidence intervals (CI) were used to assess the results.

Results

Four trials reported olaparib, olaparib plus abiraterone and apalutamide plus abiraterone. radiographic progression-free survival (rPFS) was significantly lower in patients on apalutamide plus abiraterone compared to olaparib (HR, 1.43; 95% CI, 1.06-1.93). rPFS was similar for olaparib plus abiraterone and olaparib (HR, 1.35; 95% CI, 0.99-1.84); likewise, olaparib plus abiraterone and apalutamide plus abiraterone were similar (HR, 1.06; 95% CI, 0.83-1.35). In addition, there was no significant difference between the three interventions for OS. But olaparib has the highest probability of being a preferred treatment for improving rPFS and OS.

Conclusion

rPFS was in favor of olaparib compared with apalutamide plus abiraterone. But there were no difference between olaparib plus abiraterone and either olaparib or apalutamide plus abiraterone. Apalutamide plus abiraterone might be the most preferred intervention in cases where AEs are involved.

Systematic review registration

https://inplasy.com, identifier INPLASY2023100072.

MYC is a regulator of androgen receptor inhibition-induced metabolic requirements in prostate cancer

Advanced prostate cancers are treated with therapies targeting the androgen receptor (AR) signaling pathway. While many tumors initially respond to AR inhibition, nearly all develop resistance. It is critical to understand how prostate tumor cells respond to AR inhibition in order to exploit therapy-induced phenotypes prior to the outgrowth of treatment-resistant disease. Here, we comprehensively characterize the effects of AR blockade on prostate cancer metabolism using transcriptomics, metabolomics, and bioenergetics approaches. The metabolic response to AR inhibition is defined by reduced glycolysis, robust elongation of mitochondria, and increased reliance on mitochondrial oxidative metabolism. We establish DRP1 activity and MYC signaling as mediators of AR-blockade-induced metabolic phenotypes. Rescuing DRP1 phosphorylation after AR inhibition restores mitochondrial fission, while rescuing MYC restores glycolytic activity and prevents sensitivity to complex I inhibition. Our study provides insight into the regulation of treatment-induced metabolic phenotypes and vulnerabilities in prostate cancer.

GAD1 contributes to the progression and drug resistance in castration resistant prostate cancer

BACKGROUND

Prostate cancer is currently the second most lethal malignancy in men worldwide due to metastasis and invasion in advanced stages. Studies have revealed that androgen deprivation therapy can induce stable remission in patients with advanced prostate cancer, although most patients will develop castration-resistant prostate cancer (CRPC) in 1-2 years. Docetaxel and enzalutamide improve survival in patients with CRPC, although only for a short time, eventually patients develop primary or secondary resistance, causing disease progression or biochemical relapse.

METHODS

The gene expression profiles of docetaxel-sensitive or -resistant prostate cancer cell lines, namely GSE33455, GSE36135, GSE78201, GSE104935, and GSE143408, were sequentially analyzed for differentially expressed genes and progress-free interval significance. Subsequently, the overall survival significance and clinic-pathological features were analyzed by the R package. The implications of hub genes mutations, methylation in prostate cancer and the relationship with the tumor immune cell infiltration microenvironment were assessed with the help of cBioPortal, UALCAN and TISIDB web resources. Finally, effects of the hub genes on the progression and drug resistance in prostate cancer were explored using reverse transcription-polymerase chain reaction (RT-PCR), immunohistochemistry, cell phenotype, and drug sensitivity.

RESULT

Glutamate decarboxylase 1 (GAD1) was tentatively identified by bioinformatic analysis as an hub gene for the development of drug resistance, including docetaxel and enzalutamide, in prostate cancer. Additionally, GAD1 expression, mutation and methylation were significantly correlated with the clinicopathological features and the tumor immune microenvironment. RT-PCR, immunohistochemistry, cell phenotype and drug sensitivity experiments further demonstrated that GAD1 promoted prostate cancer progression and decreased the therapeutic effect of docetaxel or enzalutamide.

CONCLUSION

This research confirmed that GAD1 was a hub gene in the progression and development of drug resistance in prostate cancer. This helped to explain prostate cancer drug resistance and provides new immune-related therapeutic targets and biomarkers for it.

ZNF397 Loss Triggers TET2-driven Epigenetic Rewiring, Lineage Plasticity, and AR-targeted Therapy Resistance in AR-dependent Cancers

Cancer cells exhibit phenotypical plasticity and epigenetic reprogramming, which allows them to evade lineage-dependent targeted treatments by adopting lineage plasticity. The underlying mechanisms by which cancer cells exploit the epigenetic regulatory machinery to acquire lineage plasticity and therapy resistance remain poorly understood. We identified Zinc Finger Protein 397 (ZNF397) as a bona fide co-activator of the androgen receptor (AR), essential for the transcriptional program governing AR-driven luminal lineage. ZNF397 deficiency facilitates the transition of cancer cell from an AR-driven luminal lineage to a Ten-Eleven Translocation 2 (TET2)-driven lineage plastic state, ultimately promoting resistance to therapies inhibiting AR signaling. Intriguingly, our findings indicate that TET2 inhibitor can eliminate the AR targeted therapies resistance in ZNF397-deficient tumors. These insights uncover a novel mechanism through which prostate and breast cancers acquire lineage plasticity via epigenetic rewiring and offer promising implications for clinical interventions designed to overcome therapy resistance dictated by lineage plasticity.

Statement of Significance

This study reveals a novel epigenetic mechanism regulating tumor lineage plasticity and therapy response, enhances understanding of drug resistance and unveils a new therapeutic strategy for prostate cancer and other malignancies. Our findings also illuminate TET2's oncogenic role and mechanistically connect TET2-driven epigenetic rewiring to lineage plasticity and therapy resistance.

Causal inferences and real-world evidence: A comparative effectiveness evaluation of abiraterone acetate against enzalutamide

Regulatory authorities are recognizing the need for real-world evidence (RWE) as a complement to randomized controlled trials in the approval of drugs. However, RWE needs to be fit for regulatory purposes. There is an ongoing discussion regarding whether pre-publication of a protocol on appropriate repositories, e.g. ClinicalTrials.gov, would increase the quality of RWE or not. This paper illustrates that an observational study based on a pre-published protocol can entail the same level of detail as a protocol for a randomized experiment. The strategy is exemplified by designing a comparative effectiveness evaluation of abiraterone acetate against enzalutamide in clinical practice. These two cancer drugs are prescribed to patients with advanced prostate cancer. Two complementary designs, including pre-analysis plans, were published before data on outcomes and proxy-outcomes were obtained. The underlying assumptions are assessed and both analyses show an increased mortality risk from being prescribed abiraterone acetate compared to enzalutamide.

Associations of quantitative whole-body PSMA-PET metrics with PSA progression status under long-term androgen deprivation therapy in prostate cancer patients: a retrospective single-center study

PURPOSE

To evaluate whether quantitative whole-body (WB) PSMA-PET metrics under long-term androgen deprivation therapy (ADT) and/or androgen receptor signaling inhibitors (ARSi) are associated with PSA progression.

METHODS

Patients who underwent at least 2 68Ga-PSMA-11 PET/CT scans between October 2016 and April 2021 (n = 372) and started a new line of ADT ± ARSi between PET1 and PET2 were retrospectively screened for inclusion. We investigated the association between PCWG3-defined PSA progression status at PET2 and the following PSMA-PET parameters: appearance of new lesions on PET2, ≥ 20% increase in WB-PSMA tumor volume (WB-PSMA-VOL), progression of disease (PD) by RECIP 1.0, and ≥ 30% increase in WB-PSMA-SUVmean from PET1 to PET2. Spearman's rank correlation coefficients and Fisher's exact test were used to evaluate the associations.

RESULTS

Thirty-five patients were included: 12/35 (34%) were treated with ADT only and 23/35 (66%) with ARSi ± ADT. The median time between PET1 and PET2 was 539 days. Changes (%) in median PSA levels, WB-PSMA-SUVmean, and WB-PSMA-VOL from PET1 to PET2 were -86%, -23%, and -86%, respectively. WB-PSMA-VOL ≥ 20%, new lesions, RECIP-PD, and WB-PSMA-SUVmean ≥ 30% were observed in 5/35 (14%), 9/35 (26%), 5/35 (14%), and 4/35 (11%) of the whole cohort, in 3/9 (33%), 7/9 (78%), 3/9 (33%), and 2/9 (22%) of patients with PSA progression at PET2, and in 2/26 (8%), 2/26 (8%), 2/26 (8%), and 2/26 (8%) of patients without PSA progression at PET2 (p = 0.058, p < 0.001, p = 0.058, p = 0.238, respectively). Changes in PSA were correlated to percent changes in WB-PSMA-VOL and WB-PSMA-SUVmean (Spearman ρ: 0.765 and 0.633, respectively; p < 0.001).

CONCLUSION

Changes in PSA correlated with changes observed on PSMA-PET, although discordance between PSA and PSMA-PET changes was observed. Further research is necessary to evaluate if PSMA-PET parameters can predict progression-free survival and overall survival and serve as novel endpoints in clinical trials.

The utility of the [-2]pro-prostate-specific antigen level as a prognostic marker in patients with castration-resistant prostate cancer treated with enzalutamide

BACKGROUND

The prostate health index (phi) derived using [-2]pro-prostate-specific antigen (p2PSA), a precursor of PSA, has been shown to predict cancer in the gray zone. However, the utility of p2PSA in predicting outcomes for castration-resistant prostate cancer (CRPC) patients remains unknown. Therefore, in this study, we aimed to evaluate the usefulness of p2PSA in predicting the efficacy and prognosis of enzalutamide treatment in CRPC patients.

METHODS

We conducted a prospective study of CRPC patients treated with enzalutamide at our institution, measuring p2PSA levels in 98 pre-treatment serum samples. All patients were divided into two groups based on the median values of each parameter. The PSA progression-free survival (PSA-PFS) and overall survival (OS) were compared using the Kaplan-Meier method. This study was approved by the Institutional Review Board of Gunma University Hospital (IRB No. 2021-092, 1983).

RESULTS

The median PSA level before enzalutamide treatment was 25.59 ng/mL, the median p2PSA level was 208.75 pg/mL, and the median phi was 187.95. PSA, p2PSA, and phi were not all predictors of PSA-PFS. However, the OS was significantly better in the low-value groups (log-rank p-values of PSA, p2PSA, and phi were 0.024, 0.034, and 0.018, respectively). In the docetaxel (DOC)-naive group (n = 58), PSA was not a predictor of OS, but p2PSA and phi were significantly associated with better OS in the low group. This relationship was not observed in the DOC-treated group.

CONCLUSIONS

Our study elucidates the usefulness of p2PSA in predicting outcomes for CRPC patients treated with enzalutamide. It suggests that p2PSA and phi may be prognostic markers after enzalutamide administration in CRPC patients.

Myocardial bridge in a patient with castration-resistant metastatic prostate cancer treated with enzalutamide

INTRODUCTION

Myocardial bridge is a morphological anomaly of the heart characterised by the presence of a myocardial segment above a coronary artery, which results in a higher risk of cardiovascular events. In patients with prostate cancer treated with androgen receptor-targeted agents, a higher risk of cardiotoxicity was observed.

CASE REPORT

An 88 years old man with metastatic castration-resistant prostate cancer in treatment with enzalutamide, denosumab, and triptorelin presented to our attention complaining dyspnoea and angina pectoris.

MANAGEMENT AND OUTCOME

Blood examinations revealed normal Troponin I levels. Transthoracic echocardiography revealed no signs of acute myocardial ischaemia. The treadmill stress test revealed S-T tract under levelling in V4-V6 with a very slow resolution. Coronary angiography identified a myocardial bridge in the medium tract of the interventricular anterior artery. Due to these findings, ranolazine and simvastatin were started and, after multidisciplinary assessment, we decided to continue the treatment with enzalutamide. At the first follow-up visit echocardiography found out the cardiological reports stability and no therapy changes were performed. During follow-up visit cardiological revaluation showed reports stability and no therapy changes were performed.

DISCUSSION

Due to the high prevalence of prostate cancer in elderly patients at high cardiovascular risk and the increasing use of androgen receptor-targeted agent, a multidisciplinary approach is highly recommended to weigh survival benefits on toxicities. This case report may support the use of androgen receptor-targeted agent in elderly patients with controlled cardiovascular diseases, a population that is often excluded from randomised trials.

Systemic Therapies for Metastatic Castration-Resistant Prostate Cancer: An Updated Review

The introduction of novel therapeutic agents for advanced prostate cancer has led to a wide range of treatment options for patients with metastatic castration-resistant prostate cancer (mCRPC). In the past decade, new treatment options for mCRPC, including abiraterone, enzalutamide, docetaxel, cabazitaxel, sipuleucel-T, radium-223, 177Lu-PSMA-617, and Olaparib, have demonstrated a survival benefit in phase 3 trials. Bone-modifying agents have become part of the overall treatment strategy for mCRPC, in which denosumab and zoledronic acid reduce skeletal-related events. Recently, androgen receptor-signaling inhibitors (ARSIs) and docetaxel have been used upfront against metastatic castration-sensitive prostate cancer. Further, triplet therapy with ARSI, docetaxel, and androgen deprivation therapy is emerging. However, cross-resistance may occur between these treatments, and the optimal treatment sequence must be considered. The sequential administration of ARSIs, such as abiraterone and enzalutamide, is associated with limited efficacy; however, cabazitaxel is effective for patients with mCRPC who were previously treated with docetaxel and had disease progression during treatment with ARSI. Radioligand therapy with 177Lu-PSMA-617 is a new effective class of therapy for patients with advanced PSMA-positive mCRPC. Tumors with gene alterations that affect homologous recombination repair, such as BRCA1 and BRCA2 alterations, are sensitive to poly (adenosine diphosphate-ribose) polymerase (PARP) inhibitors in mCRPC. This review sought to highlight recent advances in systemic therapy for mCRPC and strategies to support patient selection and treatment sequencing.

Treatment Patterns, Clinical Outcomes, Health Care Resource Utilization and Costs in Older Patients With Metastatic Castration-Resistant Prostate Cancer in the United States: An Analysis of SEER-Medicare Data

BACKGROUND

Prostate cancer (PC) is more likely to develop in men ≥65 years old than in those <65 years old. This study aimed to generate real-world evidence on treatment patterns, clinical outcomes, health care resource utilization (HCRU), and costs among older patients with metastatic castration-resistant PC (mCRPC).

MATERIALS AND METHODS

A claims algorithm based on treatments expected for mCRPC was used to identify men ≥65 years old with mCRPC in the SEER-Medicare data between 2007 and 2019. The index date was defined as the date of the start of first-line therapy (1L). Treatment patterns and all-cause and PC-specific HCRU and costs were measured in the 12 months preindex period and the postindex follow-up period. Time to next treatment or death (TNTD) and overall survival (OS) were assessed in the follow-up period.

RESULTS

A total of 4758 patients met the eligibility criteria and received 1L treatment. Among these 1L patients, 57.4% subsequently received second-line (2L) treatment; among patients receiving 2L treatment, 49.3% subsequently received third-line (3L) treatment. Abiraterone, enzalutamide, and docetaxel were most common regimens in 1L (41.9%, 22.0%, 22.0%, respectively), 2L (33.3%, 32.7%, 13.6%, respectively), and 3L (17.9%, 25.1%, 22.3%, respectively). On average, patients had 1.2 inpatient admissions, 1.1 emergency room visits, and 27.6 outpatient visits per year during follow-up. The mean total all-cause and PC-related costs during the follow-up period were $111,060 and $99,540 per-patient-per-year, respectively. Median TNTD was 9.3, 6.5, and 5.7 months for 1L, 2L, and 3L, respectively. Median OS from the start of 1L treatment for mCRPC was 21.5 months.

DISCUSSION

Among older patients with mCRPC, high attrition from 1L to subsequent lines of therapy was observed. Median TNTD was <1 year and median OS was <2 years. These results highlight a need to introduce more effective mCRPC therapies in 1L to improve clinical outcomes for older patients.