Detecting androgen receptor (AR), AR variant 7 (AR-V7), prostate-specific membrane antigen (PSMA), and prostate-specific antigen (PSA) gene expression in CTCs and plasma exosome-derived cfRNA in patients with metastatic castration-resistant prostate cancer (mCRPC) by integrating the VTX-1 CTC isolation system with the QIAGEN AdnaTest.

BACKGROUND: Therapies for metastatic castration-resistant prostate cancer (mCRPC) include targeting the androgen receptor (AR) with androgen receptor inhibitors (ARIs) and prostate-specific membrane antigen (PSMA). Having the ability to detect AR, AR splice variant 7 (AR-V7), or PSMA in circulating tumor cells (CTCs) or circulating exosomal cell-free RNA (cfRNA) could be helpful to guide selection of the appropriate therapy for each individual patient. The Vortex Biosciences VTX-1 system is a label-free CTC isolation system that enables the detection of the expression of multiple genes in both CTCs and exosomal cfRNA from the same blood sample in patients with mCRPC. Detection of both AR-V7 and PSMA gene expression in both CTCs and cfRNA simultaneously has not yet been reported. METHODS: To characterize the combined VTX-1-AdnaDetect workflow, 22Rv1 cancer cells were spiked into blood from healthy donors and processed with the VTX-1 to mimic patient samples and assess performances (capture efficiency, purity, AR and AR-V7 expression). Then, we collected 19 blood samples from 16 patients with mCRPC and therapeutic resistance to androgen receptor inhibitors (ARIs). Plasma was separated and the plasma-depleted blood was processed further with the VTX-1 to collect CTCs. Both plasma exosomal cfRNA and CTCs were subsequently analyzed for AR, AR-V7, PSMA, and prostate-specific antigen (PSA) mRNA expression using the AdnaTest ProstateCancerPanel AR-V7 assay. RESULTS: AR-V7 expression could be detected in 22Rv1 cells spiked into blood from healthy volunteers as well as in CTCs and plasma-derived exosomal cfRNA from patients with mCRPC by processing blood with the VTX-1 CTC isolation system followed by the AdnaTest ProstateCancerPanel AR-V7 assay. 94.7% of patient blood samples (18/19) had detectable AR expression in either CTCs or exosomal cfRNA (16 in CTCs, 12 in cfRNA). 15.8% of the 19 patient blood samples (3/19) were found to have AR-V7-positive (AR-V7+) CTCs, one of which was also AR-V7+ in the exosomal cfRNA analysis. 42.1% of patient blood samples (8/19) were found to be PSMA positive (PSMA+): 26.3% (5/19) were PSMA+ in the CTC analysis and 31.6% (6/19) were PSMA+ in the exosomal cfRNA analysis. Of those 8 PSMA+ samples, 2 had detectable PSMA only in CTCs, and 3 had detectable PSMA only in exosomal cfRNA. CONCLUSION: VTX-1 enables isolation of CTCs and plasma exosomes from a single blood draw and can be used for detecting AR-V7 and PSMA mRNA in both CTCs and cfRNA in patients with mCRPC and resistance to ARIs. This technology facilitates combining RNA measurements in CTCs and exosomal cfRNA for future studies to develop potentially clinically relevant cancer biomarker detection in blood.

Discovery of CBPD-409 as a Highly Potent, Selective, and Orally Efficacious CBP/p300 PROTAC Degrader for the Treatment of Advanced Prostate Cancer.

CBP/p300 are critical transcriptional coactivators of the androgen receptor (AR) and are promising cancer therapeutic targets. Herein, we report the discovery of highly potent, selective, and orally bioavailable CBP/p300 degraders using the PROTAC technology with CBPD-409 being the most promising compound. CBPD-409 induces robust CBP/p300 degradation with DC50 0.2-0.4 nM and displays strong antiproliferative effects with IC50 1.2-2.0 nM in the VCaP, LNCaP, and 22Rv1 AR+ prostate cancer cell lines. It has a favorable pharmacokinetic profile and achieves 50% of oral bioavailability in mice. A single oral administration of CBPD-409 at 1 mg/kg achieves >95% depletion of CBP/p300 proteins in the VCaP tumor tissue. CBPD-409 exhibits strong tumor growth inhibition and is much more potent and efficacious than two CBP/p300 inhibitors CCS1477 and GNE-049 and the AR antagonist Enzalutamide. CBPD-409 is a promising CBP/p300 degrader for further extensive evaluations for the treatment of advanced prostate cancer and other types of human cancers.

The design, synthesis and bioactivity evaluation of novel androgen receptor degraders based on hydrophobic tagging.

Prostate Cancer (PCa) easily progress to metastatic Castration-Resistant Prostate Cancer (mCRPC) that remains a significant cause of cancer-related death. Androgen receptor (AR)-dependent transcription is a major driver of prostate tumor cell proliferation. Proteolysis-targeting chimaera (PROTAC) technology based on Hydrophobic Tagging (HyT) represents an intriguing strategy to regulate the function of therapeutically androgen receptor proteins. In the present study, we have designed, synthesized, and evaluated a series of PROTAC-HyT AR degraders using AR antagonists, RU59063, which were connected with adamantane-based hydrophobic moieties by different alkyl chains. Compound D-4-6 exhibited significant AR protein degradation activity, with a degradation rate of 57 % at 5 µM and nearly 90 % at 20 µM in 24 h, and inhibited the proliferation of LNCaP cells significantly with an IC50 value of 4.77 ± 0.26 µM in a time-concentration-dependent manner. In conclusion, the present study lays the foundation for the development of a completely new class of therapeutic agents for the treatment of mCRPC, and further design and synthesis of AR-targeting degraders are currently in progress for better degradation rate.

Real-world analysis of apalutamide-associated skin rash in Chinese patients with prostate cancer.

PURPOSE: This study aimed to explore the clinical characteristics of apalutamide-associated skin rash and management of skin rash in real-world Chinese patients with prostate cancer. METHODS: We investigated 138 patients with prostate cancer who received apalutamide in the Second Hospital of Tianjin Medical University from January 2022 to March 2023. The primary end points were the incidence of skin rash and the time to skin rash. The second end points were the grade of skin rash, the time to remission, the rate of recurrence of skin rash, clinical risk factors and management of skin rash. RESULTS: One hundred patients were analyzed. Patients were a median of 73 years old (IQR 68-77.75). Thirty-two patients (32%) developed apalutamide­associated skin rash. The median time to incidence and remission of skin rash were 57.5 and 11.5 days, respectively. Of 32 skin rash, 27 patients had apalutamide therapy maintained after rash remission. There were seven patients having recurrence of skin rash. By multivariable logistic regression analysis, we revealed that hypertension history (OR 3.22, 95% CI 1.09-9.53, p = 0.035), bad life-styles (OR 3.29, 95% CI 1.11-9.8, p = 0.032), ECOG ≥ 1 (OR 3.92, 95% CI 1.33-11.55, p = 0.013), and high tumor burden (OR 3.13, 95% CI 1.07-9.14, p = 0.037) were independently associated with higher incidence of skin rash. CONCLUSION: Nearly one-third of Chinese patients experienced skin rash after taking apalutamide in our study. The poor health patients might have a higher incidence of apalutamide-associated skin rash.

Selective Androgen Receptor Modulators-Transformative Drugs or Heralds of the Next Drug Epidemic?

This Viewpoint examines whether selective androgen receptor modulators have the potential to be transformative drugs or whether they herald the next drug epidemic.

Treatments Targeting the Androgen Receptor and Its Splice Variants in Breast Cancer.

Breast cancer is a major cause of death worldwide. The complexity of endocrine regulation in breast cancer may allow the cancer cells to escape from a particular treatment and result in resistant and aggressive disease. These breast cancers usually have fewer treatment options. Targeted therapies for cancer patients may offer fewer adverse side effects because of specificity compared to conventional chemotherapy. Signaling pathways of nuclear receptors, such as the estrogen receptor (ER), have been intensively studied and used as therapeutic targets. Recently, the role of the androgen receptor (AR) in breast cancer is gaining greater attention as a therapeutic target and as a prognostic biomarker. The expression of constitutively active truncated AR splice variants in breast cancer is a possible mechanism contributing to treatment resistance. Therefore, targeting both the full-length AR and AR variants, either through the activation or suppression of AR function, depending on the status of the ER, progesterone receptor, or human epidermal growth factor receptor 2, may provide additional treatment options. Studies targeting AR in combination with other treatment strategies are ongoing in clinical trials. The determination of the status of nuclear receptors to classify and identify patient subgroups will facilitate optimized and targeted combination therapies.

A Phase I Study of Acapatamab, a Half-life Extended, PSMA-Targeting Bispecific T-cell Engager for Metastatic Castration-Resistant Prostate Cancer.

PURPOSE: Safety and efficacy of acapatamab, a prostate-specific membrane antigen (PSMA) x CD3 bispecific T-cell engager were evaluated in a first-in-human study in metastatic castration-resistant prostate cancer (mCRPC). PATIENTS AND METHODS: Patients with mCRPC refractory to androgen receptor pathway inhibitor therapy and taxane-based chemotherapy received target acapatamab doses ranging from 0.003 to 0.9 mg in dose exploration (seven dose levels) and 0.3 mg (recommended phase II dose) in dose expansion intravenously every 2 weeks. Safety (primary objective), pharmacokinetics, and antitumor activity (secondary objectives) were assessed. RESULTS: In all, 133 patients (dose exploration, n = 77; dose expansion, n = 56) received acapatamab. Cytokine release syndrome (CRS) was the most common treatment-emergent adverse event seen in 97.4% and 98.2% of patients in dose exploration and dose expansion, respectively; grade ≥ 3 was seen in 23.4% and 16.1%, respectively. Most CRS events were seen in treatment cycle 1; incidence and severity decreased at/beyond cycle 2. In dose expansion, confirmed prostate-specific antigen (PSA) responses (PSA50) were seen in 30.4% of patients and radiographic partial responses in 7.4% (Response Evaluation Criteria in Solid Tumors 1.1). Median PSA progression-free survival (PFS) was 3.3 months [95% confidence interval (CI): 3.0-4.9], radiographic PFS per Prostate Cancer Clinical Trials Working Group 3 was 3.7 months (95% CI: 2.0-5.4). Acapatamab induced T-cell activation and increased cytokine production several-fold within 24 hours of initiation. Treatment-emergent antidrug antibodies were detected in 55% and impacted serum exposures in 36% of patients in dose expansion. CONCLUSIONS: Acapatamab was safe and tolerated and had a manageable CRS profile. Preliminary signs of efficacy with limited durable antitumor activity were observed. Acapatamab demonstrated pharmacokinetic and pharmacodynamic activity.

Targeting Androgen Receptor Mutations in Metastatic Castration-Resistant Prostate Cancer with a Novel Androgen Biosynthesis Inhibitor.

Multiple therapeutic advances in recent years have significantly improved outcomes for patients with metastatic prostate cancer, including utilization of combination androgen receptor (AR) pathway inhibitors and/or taxane chemotherapy in earlier, hormone-sensitive disease.1 Unfortunately, patients typically still develop metastatic castration-resistant prostate cancer (mCRPC), the lethal form of disease with limited prognosis. Despite castration resistance, the majority of patients with mCRPC continue to have AR-dependent disease through a variety of mechanisms, including emergence of AR mutations, amplifications, splice variants, and persistent AR activation via alternative pathways of androgen production.2.

Design and Synthesis of Dual-Target Inhibitors Targeting Androgen Receptors and Glucocorticoid Receptors to Overcome Antiandrogen Resistance in Castration-Resistant Prostate Cancer.

Androgen receptor (AR) antagonists play important roles in the treatment of castration-resistant prostate cancer (CRPC). The glucocorticoid receptor (GR) upregulation leads to drug resistance for clinically used antiandrogens. Therefore, blocking AR/GR signaling simultaneously has become an efficient strategy to overcome the drug resistance of CRPC. Our previous work indicated that Z19 could inhibit the activity of both AR and GR. Herein, we optimized the structure of Z19 and identified GA32 as a potent AR/GR dual inhibitor. GA32 efficiently reduced the mRNA and protein levels of AR/GR downstream genes. GA32 efficiently inhibited the proliferation of enzalutamide resistance CRPC both in vitro and in vivo. GA32 could directly bind to AR and GR, and the predicted binding modes for GA32 with AR/GR suggested that GA32 binds to the AR or GR hormone binding pocket. This work provides a potential lead compound with dual AR/GR inhibitory activity to conquer the drug resistance of CRPC.

Prostate-Specific Membrane Antigen-Targeting Alpha Emitter via Antibody Delivery for Metastatic Castration-Resistant Prostate Cancer: A Phase I Dose-Escalation Study of 225Ac-J591.

PURPOSE: Novel therapies are needed to extend survival in metastatic castration-resistant prostate cancer (mCRPC). Prostate-specific membrane antigen (PSMA), a cell surface antigen overexpressed in PC, provides a validated target. This dose-escalation study investigated the safety, efficacy, maximum tolerated dose (MTD), and recommended phase II dose (RP2D) for 225Ac-J591, anti-PSMA monoclonal antibody J591 radiolabeled with the alpha emitter actinium-225. METHODS: Following investigational new drug-enabling preclinical studies, we enrolled patients with progressive mCRPC that was refractory to or who refused standard treatment options (including androgen receptor pathway inhibitor and had received or been deemed ineligible for taxane chemotherapy). No selection for PSMA was performed. Patients received a single dose of 225Ac-J591 at one of seven dose-escalation levels followed by expansion at the highest dose. Primary end point of dose-escalation cohort was determination of dose-limiting toxicity (DLT) and RP2D. RESULTS: Radiochemistry and animal studies were favorable. Thirty-two patients received 225Ac-J591 in an accelerated dose-escalation design (22 in dose escalation, 10 in expansion). One patient (1 of 22; 4.5%) experienced DLT in cohort 6 (80 KBq/kg) but none in cohort 7; MTD was not reached, and RP2D was the highest dose level (93.3 KBq/kg). The majority of high-grade adverse events (AEs) were hematologic with an apparent relationship with administered radioactivity. Nonhematologic AEs were generally of low grade. Prostate-specific antigen (PSA) declines and circulating tumor cell (CTC) control were observed: 46.9% had at least 50% PSA decline at any time (34.4% confirmed PSA response), and protocol-defined CTC count response occurred in 13 of 22 (59.1%). CONCLUSION: To our knowledge, this is the first-in-human phase I dose-escalation trial of a single dose of 225Ac-J591 in 32 patients with pretreated progressive mCRPC demonstrated safety and preliminary efficacy signals. Further investigation is underway.

Impact of Initial Timing of Metastatic Disease on Survival in Patients With Newly Diagnosed Metastatic Castration-Resistant Prostate Cancer Treated With Androgen Receptor Pathway Inhibitors.

INTRODUCTION: Patients with synchronous (de novo) metastatic castration-sensitive prostate cancer appear to have worse survival outcomes and shorter time to develop castration resistance than patients with metachronous disease. However, the impact of synchronous metastasis on outcomes in metastatic castration-resistant prostate cancer (mCRPC) setting is unknown in patients without prior exposure to androgen receptor pathway inhibitors (ARPIs). In this study, we assessed the impact of initial timing of metastasis (synchronous vs metachronous) on survival outcomes of patients with new-onset mCRPC in a real-world population treated with first-line abiraterone or enzalutamide. METHODS: Data were collected retrospectively from 323 patients with a confirmed diagnosis of mCRPC who received ARPIs as first-line therapy and had no prior exposure to ARPIs. The study endpoints were progression-free survival and overall survival. RESULTS: The results showed that median overall survival was significantly shorter in patients with synchronous disease than those with metachronous disease (26 vs 38.7 months, HR 1.42, 95% CI 1.09-1.86, P = .011). However, there was no difference in median progression-free survival. CONCLUSIONS: The initial presentation with synchronous metastasis remained an independent factor associated with shorter OS in the multivariable analysis. These hypothesis-generating data, after external validation, may have implications in patient counseling, prognostication, and design of future clinical trials in the new-onset mCRPC setting.

Docetaxel Provides Oncological Benefits in the Era of New-Generation Androgen Receptor Inhibitors - or Is Three a Crowd?

In recent years, several systemic therapies have been introduced for metastatic hormone-sensitive prostate cancer, including androgen deprivation therapy (ADT) combined with docetaxel (Doc) and/or new-generation androgen receptor signaling inhibitors (ARSI). Trials evaluating ADT + ARSI have consistently demonstrated an overall survival (OS) benefit for doublet therapy over ADT alone. Similarly, the STOPCaP meta-analysis showed an OS benefit in favor of ADT + Doc versus ADT alone. ARSI, Doc, and ADT have different antitumor mechanisms, thus potentiating the effect of combination therapy. Two randomized trials showed that the addition of ARSI to ADT + Doc improves OS, especially for synchronous high-volume disease. However, the real question about triplet therapy remains unanswered: whether combining Doc with ARSI improves outcomes compared to ADT + ARSI. As there are no head-to-head comparisons, this narrative review aims to summarize the current evidence regarding triplet therapy versus doublet therapy including ADT+ ARSI.

Endosomal recycling inhibitors downregulate the androgen receptor and synergise with enzalutamide.

Prostate cancer is the second most frequent cancer diagnosed in men, and accounts for one-fifth of cancer associated deaths worldwide. Despite the availability of effective prostate cancer therapies, if it is not cured by radical local treatment, progression to drug resistant metastatic prostate cancer is inevitable. Therefore, new drugs and treatment regimens are urgently required to overcome resistance. We have recently published research demonstrating that targeting the endosomal recycling pathway, a membrane transport pathway that recycles internalised cell surface proteins back to the plasma membrane, may be a novel means to downregulate clinically relevant cell surface proteins and potentially overcome drug resistance. A reverse phase protein array (RPPA) assay of breast cancer cells treated with an endosomal recycling inhibitor identified the androgen receptor (AR) as one of the top downregulated proteins. We confirmed that endosomal recycling inhibitors also downregulated AR in prostate cancer cells and show that this occurs at the transcriptional level. We also found that endosomal recycling inhibitors synergise with enzalutamide, a standard-of-care therapy for prostate cancer. Our data suggest that combining recycling inhibitors with hormone receptor antagonists may enhance their efficacy and reduce the emergence of drug resistance.

Discovery of (2S)-N-(6-Cyano-5-(trifluoromethyl)pyridin-3-yl)-3-(6-(4-cyanophenyl)-3,6-diazabicyclo[3.1.1]heptan-3-yl)-2-hydroxy-2-methylpropanamide as a Highly Potent and Selective Topical Androgen Receptor Antagonist for Androgenetic Alopecia Treatment.

Androgenetic alopecia (AGA) is the most prevalent form of progressive hair loss disorder in both men and women, significantly impacting their appearance and overall quality of life. Overactivation of the AR signaling pathway in dermal papilla cells (DPCs) plays a crucial role in the development and progression of AGA. Considering the severe systemic side effects associated with oral AR antagonists, the idea of developing of topical AR antagonists with rapid metabolic deactivation properties emerged as a promising approach. Herein, through systematic structural optimization, we successfully identified compound 30a as a potent and selective AR antagonist with favorable pharmacokinetic properties, resulting in high skin exposure and low plasma exposure following topical administration. Importantly, in both hair-growth and AGA mouse models, compound 30a showed potent hair-growth-promoting effects without any noticeable toxicity. These findings suggest that compound 30a holds significant potential as a topical AR antagonist for treating AGA patients.

Novel androgen receptor inhibitors for metastatic hormone-sensitive prostate cancer: Current application and future perspectives.

Androgen receptor (AR) signaling is essential in prostate cancer treatment. For many years, androgen deprivation therapy (ADT) has been primarily applied to manage advanced prostate cancer. However, most individuals with metastatic hormone-sensitive prostate cancer (mHSPC) administered ADT alone are at risk of developing metastatic castration-resistant prostate cancer (mCRPC) in less than two years. New approaches employing novel AR inhibitors (ARi) as intensified upfront systemic treatment in mHSPC have recently demonstrated substantial benefits in delaying disease progression and prolonging overall survival. Administration of novel ARi has become the new standard of care in mHSPC. The new landscape simultaneously makes treatment choice more challenging. This review provides comprehensive data on molecular structure, pharmaceutical properties, and efficacy and safety profiles reported by pivotal clinical trials. We also discuss future directions with ongoing Phase III trials of novel ARi in mHSPC. Considering these biological and clinical insights, this review aimed to provide a comprehensive understanding of differences in the development and applications of novel ARi for mHSPC, which may be helpful in designing strategies for first-line treatment choices.

Untargeted lipidomics reveal association of elevated plasma C18 ceramide levels with reduced survival in metastatic castration-resistant prostate cancer patients.

Emerging evidence highlights the potential prognostic relevance of circulating lipids in metastatic castration-resistant prostate cancer (mCRPC), with a proposed 3-lipid signature. This study aims to analyze the lipidomic profiles of individuals with mCRPC to identify lipid species that could serve as predictive indicators of prognosis and therapeutic response. Plasma samples were collected from mCRPC patients initiating first-line treatment (1 L) (n = 29) and those previously treated with at least two lines of therapy (> 2 L) (n = 19), including an androgen-receptor signaling inhibitor and a taxane. Employing an untargeted lipidomic approach, lipids were extracted from the plasma samples and subjected to analysis. A comprehensive identification and quantification of 789 plasma lipids was achieved. Notably, 75 species displayed significant dysregulation in > 2 L patients in comparison to the 1 L group. Among these, 63 species exhibited elevated levels, while 12 were reduced. Patients included in > 2 L cohort showed elevated levels of acylcarnitines (CAR), diacylglycerols (DG), phosphatidylethanolamines (PE), triacylglycerols (TG), and ceramides (Cer). Notably, some upregulated lipids, including CAR 14:0, CAR 24:1, Cer d18:1/16:0, Cer d18:1/18:0 (C18 Cer), Cer d18:2/18:0, Cer d18:1/24:1, and Cer d20:1/24:1, showed significant associations with overall survival (OS) in univariate models. Specifically, increased levels of C18 Cer remained significantly associated with poorer OS in the multivariate model, even after adjusting for treatment line and PSA levels (Hazard Ratio: 3.59 [95% Confidence Interval 1.51-8.52], p = 0.004). Employing quantitative mass spectrometry, our findings underscore the independent prognostic significance of C18 Cer in individuals with mCRPC. This discovery opens avenues for further studies within this field.

Targeting myeloid chemotaxis to reverse prostate cancer therapy resistance.

Inflammation is a hallmark of cancer1. In patients with cancer, peripheral blood myeloid expansion, indicated by a high neutrophil-to-lymphocyte ratio, associates with shorter survival and treatment resistance across malignancies and therapeutic modalities2-5. Whether myeloid inflammation drives progression of prostate cancer in humans remain unclear. Here we show that inhibition of myeloid chemotaxis can reduce tumour-elicited myeloid inflammation and reverse therapy resistance in a subset of patients with metastatic castration-resistant prostate cancer (CRPC). We show that a higher blood neutrophil-to-lymphocyte ratio reflects tumour myeloid infiltration and tumour expression of senescence-associated mRNA species, including those that encode myeloid-chemoattracting CXCR2 ligands. To determine whether myeloid cells fuel resistance to androgen receptor signalling inhibitors, and whether inhibiting CXCR2 to block myeloid chemotaxis reverses this, we conducted an investigator-initiated, proof-of-concept clinical trial of a CXCR2 inhibitor (AZD5069) plus enzalutamide in patients with metastatic CRPC that is resistant to androgen receptor signalling inhibitors. This combination was well tolerated without dose-limiting toxicity and it decreased circulating neutrophil levels, reduced intratumour CD11b+HLA-DRloCD15+CD14- myeloid cell infiltration and imparted durable clinical benefit with biochemical and radiological responses in a subset of patients with metastatic CRPC. This study provides clinical evidence that senescence-associated myeloid inflammation can fuel metastatic CRPC progression and resistance to androgen receptor blockade. Targeting myeloid chemotaxis merits broader evaluation in other cancers.

Survival Trend in Individuals With De Novo Metastatic Prostate Cancer After the Introduction of Doublet Therapy.

Importance: Recently, life-prolonging treatments for patients with advanced prostate cancer have been introduced in clinical practice. Objective: To investigate if the introduction of doublet therapy is associated with changes in survival on a population-basis. Design, Setting, and Participants: This nationwide population-based cohort study used data from the Prostate Cancer data Base Sweden from 2008 to 2020. Men registered with de novo metastatic castration-sensitive prostate cancer (mCSPC) were included. Exposure: The proportion of men with mCSPC who received doublet therapy, ie, androgen deprivation therapy plus androgen receptor pathway inhibitor drugs or chemotherapy was assessed. Main Outcomes and Measures: Standardized overall survival, taking age, comorbidity, and cancer characteristics into consideration, was estimated by use of a parametric survival model. Results: A total of 11 382 men were included in this study (median [IQR] age, 74.0 [68-81] years). There was a shift toward less advanced prostate cancer during the study period with a decrease in median (IQR) prostate-specific antigen at diagnosis in men with mCSPC from 145 (39-571) ng/mL to 107 (27-426) ng/mL. Upfront treatment with doublet therapy in these men simultaneously increased from 1% (7 of 991) in 2016 to 44% (402 of 922) in 2020. The adjusted 5-year overall survival increased from 26% (95% CI, 25%-28%) from 2008 to 2012 to 35% (95% CI, 31%-40%) from 2017 to 2020. During the first 5 years after diagnosis, there was an increase in mean survival of 6 months, from 2.7 (95% CI, 2.6-2.8) years from 2008 to 2012 to 3.2 (95% CI, 3.1-3.1) years from 2017 to 2020. Conclusions and Relevance: In parallel with improvements in treatment of advanced prostate cancer, a clinically meaningful increase in mean survival was observed in men with de novo mCSPC in Sweden between 2008 and 2020 in this study.

The biology behind combining poly [ADP ribose] polymerase and androgen receptor inhibition for metastatic castration-resistant prostate cancer.

For about a decade, poly [ADP ribose] polymerases (PARP) inhibitors have been used almost exclusively to treat tumours that are deficient in one of the BRCA genes. In advanced prostate cancer, which is largely driven by the activity of the androgen receptor (AR), accumulating preclinical evidence has suggested an interplay between the AR and PARP, which could be therapeutically exploited independently of defects in the tumour's DNA homologous recombination repair (HRR) machinery. This includes the regulation of HRR genes by the AR, a mutual influence between the activities of PARP and the AR, and the co-localisation of BRCA2 to the retinoblastoma gene in the human genome. Based on these findings, randomised clinical trials have been initiated to study the addition of a PARP inhibitor to AR pathway inhibitor therapy. Three of four randomised studies demonstrated a significantly increased anti-tumour activity in men with metastatic prostate cancer, irrespective of HRR gene alterations. In this review, we summarise the available preclinical evidence that provides the rationale for the combination of inhibitors for PARP and the AR and discuss how it might contribute to the efficacy observed in the clinic.