NCT06774027

Prospective Registry of ADC as First- and Second-line Treatment for Breast Cancer

ENCORE: Multicenter ProspectivE Registry of Sequential ANtibody Drug COnjugates (ADCs) in HER2 Negative Metastatic BREast Cancer (MBC)

• Status: Recruiting
• Phase: —
• Study type: Observational
• Enrollment: 100 (estimated)
• Sponsor: University of California, San Francisco · Academic / Other
• Sex: All
• Age: 18 Years
• Healthy volunteers: Accepted

Summary

Antibody-drug conjugates (ADCs) have demonstrated substantial improvement in progression free survival (PFS) and overall survival (OS) in phase III clinical trials in patients with metastatic triple negative breast cancer (mTNBC) and hormone receptor positive/HER2 negative (HR+/HER2-) metastatic breast cancer (MBC), offering an effective new treatment strategy. Several outstanding questions drive the decision to use ADC drugs clinically. This is a prospective, multi-site observational study of patients with metastatic breast cancer (mBC) who are being treated with FDA-approved antibody drug conjugates (ADCs) as part of routine care and aims to collect real-world data to evaluate the impact of ADC treatment as part of routine care.

Detailed description

PRIMARY OBJECTIVES: I. Real-world progression free survival (rwPFS) of the first line of ADC under routine care (ADC1) by investigator assessment II. Real-world progression free survival (rwPFS) of the second line ADC under routine care (ADC2) by investigator assessment SECONDARY OBJECTIVES: I. To evaluate the efficacy of ADC1 and ADC2 as measured by duration of response (DOR), best overall response (BOR), disease control rate (DCR), and overall survival (OS) for each ADC. II. To evaluate key safety parameters for ADC1 and ADC2 by chart review. EXPLORATORY OBJECTIVES: I. To evaluate/identify correlative biomarkers (e.g., circulating tumor DNA (ctDNA), circulating tumor cells (CTC), and tissue spatial correlates) of response/resistance to ADCs. II. To evaluate patient reported outcomes (PROs) for each ADC. OUTLINE: Participants will have medical chart reviews and biospecimens collected for the duration of routine care with ADC1 and/or ADC2. After the last dose of ADC2, participants will continue to be followed for survival data collection via chart review every 12 weeks for up to 2 years.

Conditions

• HER2-negative Breast Cancer
• HER2 Negative Breast Carcinoma
• Metastatic Breast Cancer
• HR+ HER2 Breast Cancer
• Metastatic Triple Negative Breast Cancers
• Metastatic Triple-Negative Breast Carcinoma

Interventions

Type	Name	Description
PROCEDURE	Specimen collection	Blood specimens will be collected during regular clinical visits for correlative and exploratory analysis
DRUG	Non-Investigational Antibody-Drug Conjugates (ADC)	ADC given under usual care for the treatment of cancer
OTHER	Medical Record Review	Prospective and retrospective medical chart reviews will be conducted to obtain data for analysis.

Timeline

• Start date: 2025-10-08
• Primary completion: 2030-12-31
• Completion: 2030-12-31
• First posted: 2025-01-14
• Last updated: 2025-12-18

Locations

1 site across 1 country: United States