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

Real-world Outcomes of Patients With HER2-positive (HER2+) Metastatic Breast Cancer (mBC) After Treatment With Trastuzumab Deruxtecan (T-DXd) in the United States

Status
Completed
Phases
Unknown
Study type
Observational
Source
ClinicalTrials.gov
Registry ID
NCT06833268
Enrollment
228
Registered
2025-02-18
Start date
2025-01-20
Completion date
2025-06-16
Last updated
2025-07-08

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

HER2-positive Breast Cancer

Keywords

HER2-positive breast cancer, Real-world outcomes

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.

Detailed description

This study will utilize a longitudinal, demographically and geographically diverse database derived from Electronic Health Record data. No study medication will be supplied or administered for this protocol. The primary research objective is to describe the real-world progression-free survival (rwPFS) in HER2+ mBC patients who initiated a subsequent line of therapy (LOT) after a T-DXd-containing LOT in the metastatic setting. Secondary research objectives include describing the real-world overall survival (rwOS), patient demographics and clinical characteristics, real-world time to next treatment (rwTTNT), and real-world time to treatment discontinuation (rwTTD) in HER2+ mBC patients who initiated a subsequent LOT after a T-DXd-containing LOT in the metastatic setting. Treatment patterns and sequencing in HER2+ mBC patients for subsequent LOTs following initial treatment with T-DXd will also be assessed.

Interventions

OTHERNo drug

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

Sponsors

Daiichi Sankyo
Lead SponsorINDUSTRY

Study design

Observational model
COHORT
Time perspective
RETROSPECTIVE

Eligibility

Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No

Inclusion criteria

Patients must meet all the inclusion criteria below to be included in the study population: 1. Patients with evidence of stage IV or recurrent mBC with a metastatic diagnosis date on or after January 1, 2011. 2. Patients aged ≥18 years old at mBC diagnosis date. 3. Patients with ≥1 T-DXd-containing LOT in the metastatic setting. 4. 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. 5. 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. 6. Patients with index date occurring at least 90 days prior to end of study period (March 31st, 2024).

Exclusion criteria

No

Design outcomes

Primary

MeasureTime frameDescription
Real-world Progression-free Survival (rwPFS)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 monthsrwPFS is defined as the interval in months between the index date until the first evidence of progression or death as documented by Flatiron.

Secondary

MeasureTime frameDescription
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 monthsrwTTNT is defined as the time in months between index date and initiation of next LOT, or death, whichever occurs first.
Real-world Time to Treatment Discontinuation (rwTTD)Index date (index LOT start date) to date treatment is discontinued, up to approximately 13 years 3 monthsrwTTD is defined as the time in months between index date and date of treatment discontinuation or death, whichever occurs first.
Treatment Patterns by Type of Line of TherapyIndex date (index LOT start date) to end of study period, up to approximately 13 years 3 monthsTreatment patterns will be described by LOT (monotherapy, combination therapy, and treatment sequence).

Countries

United States

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026