Real-world Outcomes of Patients With HER2+ Metastatic Breast Cancer After Treatment With Trastuzumab Deruxtecan

NCT06833268 | Completed

• 1 other identifier: U31402-0010-NIS-MA
• Study Type: observational
• Target: 228
• Locations: 1 country
• Sites: 1

Brief Summary

This study will explore treatment patterns and clinical outcomes using the US-based Flatiron Health database to describe patients with HER2+ mBC who were previously treated with T-DXd to better characterize this population and inform internal decision making in this rapidly changing therapeutic landscape.

Conditions

HER2-positive Breast Cancer

Keywords

HER2-positive breast cancer; Real-world outcomes

Outcome Measures

Primary Outcomes (1)

• Real-world Progression-free Survival (rwPFS)

  rwPFS is defined as the interval in months between the index date until the first evidence of progression or death as documented by Flatiron.

  Index date (index LOT start date) to date of earliest disease progression >14 days after the index date or date of death, whichever occurs first, up to approximately 13 years 3 months

Secondary Outcomes (3)

• Real-world Time to Next Treatment (rwTTNT)

  Index date (index LOT start date) to next LOT start date or, in the absence of next LOT, death, whichever occurs first, up to approximately 13 years 3 months

• Real-world Time to Treatment Discontinuation (rwTTD)

  Index date (index LOT start date) to date treatment is discontinued, up to approximately 13 years 3 months

• Treatment Patterns by Type of Line of Therapy

  Index date (index LOT start date) to end of study period, up to approximately 13 years 3 months

Study Arms (1)

HER2-positive breast cancer

Patients diagnosed with HER2-positive metastatic breast cancer who initiated a subsequent LOT after the initial T-DXd-containing LOT in the metastatic setting.

Other: No drug

Interventions

No drug OTHER

This is an non-interventional, observational study. No drug will be provided or administered as part of this protocol.

HER2-positive breast cancer

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

The study population will consist of adults in the Flatiron mBC EDM who were diagnosed with HER2+ mBC during the study period and initiated a subsequent LOT after the initial T-DXd-containing LOT in the metastatic setting.

You may qualify if:

• Patients with evidence of stage IV or recurrent mBC with a metastatic diagnosis date on or after January 1, 2011.
• Patients aged ≥18 years old at mBC diagnosis date.
• Patients with ≥1 T-DXd-containing LOT in the metastatic setting.
• Patients with evidence of a subsequent LOT following the first T-DXd-containing LOT in the metastatic setting. The LOT subsequent to the first T-DXd-containing LOT in the metastatic setting will be the index LOT. Index date will be the index LOT start date.
• Patients whose closest HER2 test result (defined as immunohistochemistry \[IHC\] 3+ or in situ hybridization \[ISH\]+) recorded prior to or on the index date was a HER2+ test result.
• Patients with index date occurring at least 90 days prior to end of study period (March 31st, 2024).

Sponsors & Collaborators

• Daiichi Sankyo: lead

Study Sites (1)

Flatiron Health, Inc

New York, New York, 10013, United States

Location

Study Officials

• Project Manager

  Daiichi Sankyo

  STUDY DIRECTOR

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: RETROSPECTIVE
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: February 12, 2025
• First Posted: February 18, 2025
• Study Start: January 20, 2025
• Primary Completion: June 16, 2025
• Study Completion: June 16, 2025
• Last Updated: July 8, 2025

Record last verified: 2025-07

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)