Exploiting Heterogeneity in Hormone Therapy Response to Reveal Early Determinants of Drug Resistance in Advanced PCa (MOSAIC)

The goal of this observational study is to study intra-patient tumor and TME heterogeneity after initiation of hormonal therapy (ADT +- ARSI), while the patient is responding to treatment, to understand the drivers of hormonal therapy resistance and identify potential novel therapeutic targets in metastatic prostate cancer patients. The main question it aims to answer if intra-tumor adaptive mechanisms including expression of immune checkpoint proteins and changes in the tumor immune infiltrate are related to the induction of a senescent phenotype in response to hormonal therapy.

Participants will asked to provide an FFPE and/or fresh biopsy sample from the primary tumor or a metastatic site at baseline (before starting hormonal therapy) and during the course of hormonal therapy. Additionally, a maximum of 2 blood tubes (10ml) will be collected each time.

Study Overview

• Status: Active, not recruiting
• Conditions: Metastatic Prostate Cancer
• Intervention / Treatment: Procedure: biopsy; Procedure: Prostate biopsy

• Study Type: Observational
• Enrollment (Estimated): 30

Contacts and Locations

Study Locations

• Italy
  • VR
    • Verona, VR, Italy, 37134
      • Universita di Verona

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Patients with prostate cancer receiving care at Azienda Ospedaliera Universitaria Integrata di Verona, Italy.

Description

Inclusion Criteria Group A:

• Patients with histological diagnosis of advanced prostate cancer (defined as the presence of metastatic disease, including both metastatic hormone naïve prostate cancer patients and metastatic castration resistant prostate cancer patients);
• Patients who started ADT or ADT plus AR inhibitor therapy (Enzalutamide, Darolutamide or Apalutamide or Abiraterone) in a standard therapy.
• Have accessible metastatic and/or primitive disease to perform a biopsy safely during hormonal therapy (ADT or ADT plus AR inhibitor therapy) and before hormonal therapy (alternatively, as a basal biopsy could be used archival FFPE or frozen tumor material left over from surgical procedures or previous biopsies, if available)
• Written acceptance of informed consent to be included in the present study.
• Aged 18 or over.

Inclusion Criteria Group B:

• Patients due for prostate biopsy to confirm the diagnosis of a prostate adenocarcinoma at high risk of metastatic disease. High risk is defined as follows:
• PSA >=20ng/dL with or without imaging suggestive of metastatic prostate cancer OR
• PSA >=10 ng/mL and <= 20 ng/mL AND >=33% risk to have a high grade disease on prostate biopsy according to the MSKCC nomogram "Risk of high grade cancer of prostate biopsy" (https://www.mskcc.org/nomograms/prostate/biopsy_risk_dynamic).
• Written acceptance of informed consent to be included in the present study.
• Aged 18 or over

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Patients with histological diagnosis of advanced prostate cancer who started hormone therapy; A fresh tumor biopsies and FFPE block will be taken at baseline and after 4 weeks of hormone therapy and/or AR targeting agents. Blood samples for the isolation of plasma, serum and PBMC will be collected before the start of therapy and after 4 weeks of hormone therapy and/or AR targeting agents. The correlation of biopsies analyses and clinical data will advance the understanding of prostate cancer progression pathways and guide the design of subsequent studies in the field of personalized medicine.	Procedure: biopsy; A fresh tumor biopsies and an FFPE block will be taken at baseline (alternatively, as a basal biopsy could be used archival FFPE tumor material left over from surgical procedures or previous biopsies if available and if a fresh biopsy at baseline is not feasible or safe; in case of availability of frozen and FFPE archival blocks, 1 frozen block and 1 FFPE block will be used for the analyses) and after 2-4 weeks of hormonal treatment with ADT and/or AR inhibitors. Biopsies will be performed guided by ultrasound or CT, depending on location. From each Fresh biopsy, 2 core biopsies will be collected, 1 will be processed into an FFPE block, and the second will be processed according to freezing procedures.
Patients due for prostate biopsy to confirm the diagnosis of a prostate adenocarcinoma at high risk; A fresh tumor biopsies and FFPE block and blood samples for the isolation of plasma, serum and PBMC will be taken at baseline. This cohort was necessary because it is complex to intercept patients at the time they perform diagnostic biopsy and then obtain fresh biopsies pre-hormonal treatment. If patients of this group will metastasize, these patients will be incorpored in the other.	Procedure: Prostate biopsy; Fresh and FFPE block tumor biopsies at baseline

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
A) Density of tumor-infiltrating immune cells	Description: Density of tumor-infiltrating lymphocytes (CD3+, CD4+, CD8+, FOXP3+) assessed by multiplex immunohistochemistry in tumor biopsies from patients under hormonal therapy. Unit of Measure: Cells/mm²	From enrollment to 24 months
Tumor expression of Immune checkpoints	The investigators will pursue IHC assessment of immunomodulatory proteins. I will use a multiplexed customized IHC panel and the expression of the immunomodulatory proteins will be assessed in a semiquantitative manner (negative, 1+, 2+, 3+) in different tumor areas. I will compare the expression of immunomodulatory proteins assessed on human prostate cancer biopsies under hormonal treatment with same-patient pre-treatment therapy biopsies.	From enrollment to 24 months
Emergence of a senescent phenotype	The investigators will confirm in vivo, in human samples, the senescent phenotype described in prostate cancer preclinical models, assessing the SA-Beta-Gal activity on fresh OCT-embedded biopsies and/or testing the telomere shortening in FFPE biopsies, depending If will be feasible to collect both fresh frozen and FFPE cores biopsies.	From enrollment to 24 months
Changes in expression of prostate cancer-specific markers and therapeutic targets.	The investigators will also test the expression of prostate cancer specific markers PSMA, STEAP1, STEAP2 in response to AR blockade by IHC in pre-treatment vs post-treatment samples.	From enrollment to 24 months

Collaborators and Investigators

• Sponsor: Universita di Verona

Study record dates

Study Major Dates

• Study Start (Actual): October 17, 2024
• Primary Completion (Actual): September 11, 2025
• Study Completion (Estimated): October 17, 2026

Study Registration Dates

• First Submitted: September 23, 2025
• First Submitted That Met QC Criteria: January 12, 2026
• First Posted (Actual): January 20, 2026

Study Record Updates

• Last Update Posted (Actual): January 28, 2026
• Last Update Submitted That Met QC Criteria: January 26, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Urogenital Diseases; Genital Diseases; Genital Neoplasms, Male; Urogenital Neoplasms; Neoplasms by Site; Neoplasms; Genital Diseases, Male; Prostatic Diseases; Male Urogenital Diseases; Prostatic Neoplasms; Investigative Techniques; Specimen Handling; Clinical Laboratory Techniques; Diagnostic Techniques and Procedures; Diagnosis; Surgical Procedures, Operative; Cytological Techniques; Cytodiagnosis; Diagnostic Techniques, Surgical; Biopsy
• Other Study ID Numbers: 296CET

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No