Molecular classification of hormone-sensitive and castration-resistant prostate cancer, using nonnegative matrix factorization molecular subtyping of primary and metastatic specimens.

BACKGROUND: Despite the rapidly evolving therapeutic landscape, immunotherapy has demonstrated limited activity in prostate cancer. A greater understanding of the molecular landscape, particularly the expression of immune-related pathways, will inform future immunotherapeutic strategies. Consensus nonnegative matrix factorization (cNMF) is a novel model of molecular classification analyzing gene expression data, focusing on biological interpretation of metagenes and selecting meaningful clusters. OBJECTIVE: We aimed to identify molecular subtypes of prostate cancer using cNMF and correlate these with existing biomarkers to inform future immunotherapeutic strategies. METHODS: A cohort of archival tumor specimens from hormone-sensitive and castration-resistant disease was studied. Whole transcriptomic profiles were generated using TruSeq RNA Access technology and subjected to cNMF. Comprehensive genomic profiling was performed with the FoundationOne assay. NMF subtypes were characterized by gene expression pathways, genomic alterations and correlated with clinical data, then applied to The Cancer Genome Atlas data set. RESULTS: We studied 164 specimens, including 52 castration-resistant and 13 paired primary/metastatic specimens. cNMF identified four distinct subtypes. NMF1 (19%) is enriched for immune-related and stromal-related pathways with transforming growth factor ß (TGFß) signature. NMF2 (36%) is associated with FOXO-mediated transcription signature and AKT signaling, NMF3 (26%) is enriched for ribosomal RNA processing, while NMF4 (19%) is enriched for cell cycle and DNA-repair pathways. The most common gene alterations included TMPRSS22 (42%), TP53 (23%), and DNA-repair genes (19%), occurring across all subtypes. NMF4 is significantly enriched for MYC and Wnt-signaling gene alterations. TMB, CD8 density, and PD-L1 expression were low overall. NMF1 and NMF4 were NMF2 was associated with superior overall survival. CONCLUSIONS: Using cNMF, we identified four molecularly distinct subtypes which may inform treatment selection. NMF1 demonstrates the most inflammatory signature with asuppressive TGFß signature, suggesting potential benefit with immunotherapy combination strategies targeting TGFß and PD-(L)1. Prospective studies are required to evaluate the use of this novel model to molecularly stratify patients for optimal treatment selection.

Real-world incidence of symptomatic skeletal events and bone-modifying agent use in castration-resistant prostate cancer - an Australian multi-centre observational study.

INTRODUCTION: Bone metastases occur frequently in castration-resistant prostate cancer (CRPC) and may lead to skeletal-related events (SREs), including symptomatic skeletal events (SSEs). Bone-modifying agents (BMAs) delay SREs and SSEs. However, the real-world use of BMAs is debated given the absence of demonstrated survival advantage and potential adverse events (AEs). Our retrospective study examined BMA use and SSE rates in Australian patients with CRPC. METHODS: Patients with CRPC and bone metastases were identified from the electronic CRPC Australian Database. Patient characteristics, treatment patterns and AEs were analysed. Descriptive statistics reported baseline characteristics, SSE rates and BMA use. Comparisons between groups used t-tests and Chi-square analyses. Overall survival was calculated by the Kaplan-Meier method. RESULTS: A total of 532 eligible patients were identified with a median age of 73 years (range: 44-97 years). BMAs were prescribed in 232 men (46%), 183 of whom received denosumab. Patients receiving first-line docetaxel for CRPC were more likely to commence BMAs than those receiving abiraterone or enzalutamide (51% vs 31% vs 38%; p = 0.004). SSEs occurred in 148 men (28%), most commonly symptomatic lesions requiring intervention (75%). At the time of initial SSEs, only 28% were receiving BMAs. Patients treated at sites with lower BMA use (

Impact of access to novel therapies on the initial management of castrate-resistant prostate cancer: an Australian multicentre study.

BACKGROUND: The impact of regulatory approvals of new therapies for castration-resistant prostate cancer (CRPC) in Australia is unclear. AIMS: To determine if changes in novel therapy access in Australia affected how clinicians initially managed men with newly diagnosed CRPC. METHODS: Data from patients diagnosed with CRPC from 2013 to 2016 across three Australian hospitals were retrospectively collected. Baseline clinicopathological factors and initial management decision at the time of CRPC development (early treatment (ET) vs deferred treatment (DT)) were recorded. Categorical variables between cohorts were compared by Chi-squared analysis. Cox regression analysis was performed to assess the impact of CRPC diagnosis year on time to commencing life-prolonging systemic treatment (TTT). RESULTS: Our study identified 137 CRPC patients, with 126 (92%) patients receiving life-prolonging systemic treatment. The median age was 73 years. The initial management decision was DT in 71 (52%) patients and ET in 66 (48%) patients. There was a significant shift from DT to ET during the study period (2013-2014: DT 61% vs ET 33%; 2015-2016: DT 39% vs ET 67%; P = 0.004), with a rise in novel androgen receptor signalling inhibitor use and simultaneous reduction in first-generation antiandrogen use at CRPC development. Each successive CRPC diagnosis year was associated with shorter TTT on univariate analysis (HR: 1.5, 95% CI: 1.3-1.7, P < 0.001). CONCLUSION: Over time, clinicians are favouring earlier introduction of life-prolonging systemic treatment at the development of CRPC. This trend is largely driven by substantial uptake of novel androgen receptor signalling inhibitors as the preferred initial treatment for CRPC patients.