Andrew Armstrong

Epithelial-mesenchymal plasticity plays a critical role in many solid tumor types as a mediator of metastatic dissemination and treatment resistance. In addition, there is also a growing appreciation that the epithelial/mesenchymal status of a tumor plays a role in immune evasion and immune suppression. A deeper understanding of the immunological features of different tumor types has been facilitated by the availability of large gene expression datasets and the development of methods to deconvolute bulk RNA-Seq data. These resources have generated powerful new ways of characterizing tumors, including classification of immune subtypes based on differential expression of immunological genes. In the present work, we combine scoring algorithms to quantify epithelial-mesenchymal plasticity with immune subtype analysis to understand the relationship between epithelial plasticity and immune subtype across cancers. We find heterogeneity of epithelial-mesenchymal transition (EMT) status both within and between cancer types, with greater heterogeneity in the expression of EMT-related factors than of MET-related factors. We also find that specific immune subtypes have associated EMT scores and differential expression of immune checkpoint markers.

BACKGROUND: While enzalutamide plus androgen deprivation therapy (ADT) significantly reduces the risk of radiographic progression-free survival (rPFS) and improves overall survival in metastatic hormone-sensitive prostate cancer (mHSPC), the efficacy in clinically relevant subgroups of patients based on prior local and systemic therapy, disease volume, and risk has not been analyzed to date. These post hoc analyses of the phase 3 ARCHES trial (NCT02677896) evaluated the efficacy of enzalutamide plus ADT according to prior local and systemic treatment, disease volume, and risk, assessed at trial baseline. METHODS: In ARCHES, a global, double-blind, placebo-controlled, phase 3 study, 1150 patients with mHSPC were randomized 1:1 to receive enzalutamide (160 mg/day) plus ADT or placebo plus ADT, stratified by prior docetaxel therapy and disease volume. Primary endpoint was rPFS. Secondary endpoints included time to prostate-specific antigen progression, symptomatic skeletal events, and prostate-specific antigen and radiographic responses. Analyses of clinical endpoints were completed by prior local therapy, prior docetaxel exposure, CHAARTED (NCT00309985)-defined disease volume, and LATITUDE (NCT01715285)-defined risk groups. RESULTS: Patients were randomized to enzalutamide plus ADT (n = 574) and placebo plus ADT (n = 576). Enzalutamide plus ADT significantly improved rPFS (hazard ratio: 0.39; p < 0.0001), with similar improvements reported in all subgroups based on prior local and docetaxel treatment, disease volume, and risk. Treatment benefits were observed with enzalutamide plus ADT in multiple secondary clinical endpoints in the overall population and all subgroups. CONCLUSIONS: Enzalutamide plus ADT demonstrated clinical benefit across all patients with mHSPC, irrespective of prior local and systemic treatment, disease volume, and risk.

PURPOSE: Prostate cancer is a heterogeneous disease with variable clinical outcomes. Despite numerous recent approvals of novel therapies, castration-resistant prostate cancer remains lethal. A "real-world" clinical-genomic database is urgently needed to enhance our characterization of advanced prostate cancer and further enable precision oncology. METHODS: The Prostate Cancer Precision Medicine Multi-Institutional Collaborative Effort (PROMISE) is a consortium whose aims are to establish a repository of de-identified clinical and genomic patient data that are linked to patient outcomes. The consortium structure includes a (1) bio-informatics committee to standardize genomic data and provide quality control, (2) biostatistics committee to independently perform statistical analyses, (3) executive committee to review and select proposals of relevant questions for the consortium to address, (4) diversity/inclusion committee to address important clinical questions pertaining to racial disparities, and (5) patient advocacy committee to understand patient perspectives to improve patients' quality of care. RESULTS: The PROMISE consortium was formed by 16 academic institutions in early 2020 and a secure RedCap database was created. The first patient record was entered into the database in April 2020 and over 1000 records have been entered as of early 2021. Data entry is proceeding as planned with the goal to have over 2500 patient records by the end of 2021. CONCLUSIONS: The PROMISE consortium provides a powerful clinical-genomic platform to interrogate and address data gaps that have arisen with increased genomic testing in the clinical management of prostate cancer. The dataset incorporates data from patient populations that are often underrepresented in clinical trials, generates new hypotheses to direct further research, and addresses important clinical questions that are otherwise difficult to investigate in prospective studies.