Real World-clinical Outcomes of Tucatinib, Trastuzumab, and Capecitabine Following Trastuzumab Deruxtecan (T-DXd) for the Treatment of HER2-positive Metastatic Breast Cancer.

NCT06961331 | Completed FDA Drug

• 1 other identifier: C4251025
• Study Type: observational
• Target: 86
• Locations: 1 country
• Sites: 1

Brief Summary

A retrospective study of de-identified (to preserve patient privacy) patient information from the Flatiron Health Database to describe 3L and 4L real-world (rw) outcomes (e.g. time to next treatment, time to discontinuation, and overal survival) of the tucatinib-trastuzumab-capecitabine triplet therapy immediately following T-DXd therapy in patients diagnosed with HER2+ metastatic breast cancer (mBC) in the United States.

Conditions

Metastatic HER2+ Advanced Breast Cancer

Keywords

her2+; mBC; metastatic breast cancer; tukysa; tucatinib; breast neoplasm; Human epidermal growth factor receptor 2 positive

Outcome Measures

Primary Outcomes (4)

• Time to Next Treatment

  Time to next treatment defined as the time in months from the initiation of therapy to the initiation of subsequent LOT or death.

  1 Year

• Time to Discontinuation

  Time to treatment discontinuation defined as the time in months from initiation of therapy to discontinuation for any reason or death.

  1 Year

• Overall survival (OS)

  OS will be defined as the time in months from initiation of therapy to death from any cause.

  1 Year

• real-world Progression free survival (rwPFS)

  rwPFS will be defined as time in months from initiation of therapy to progression or death from any cause.

  1 Year

Study Arms (1)

3L+4L tucatinib triplet patients

Non-interventional, retrospective cohort analysis of participants receiving the tucatinib triplet in the 3L or 4L setting immediately following T-DXd.

Drug: Tucatinib; Drug: Trastuzumab; Drug: Capecitabine

Interventions

Tucatinib DRUG

As provided in real world practice.

3L+4L tucatinib triplet patients

Trastuzumab DRUG

As provided in real world practice.

3L+4L tucatinib triplet patients

Capecitabine DRUG

As provided in real world practice.

3L+4L tucatinib triplet patients

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 will include participants in the US Flatiron Dataset diagnosed with HER2+ mBC treated with the tucatinib triplet in the post-T-DXd setting.

You may qualify if:

• mBC diagnosis between January 1, 2017 and 6 months prior to database cutoff
• Evidence of human epidermal growth factor receptor 2 (HER2) receptor positivity prior to or up to 90 days following the mBC diagnosis date
• At least 18 years old on the mBC diagnosis date
• Treated with systemic anticancer treatment in the metastatic setting, i.e., post mBC diagnosis.
• Treated with T-DXd in the 1L or 2L or 3L setting, followed immediately by the tucatinib triplet, and at least 1 additional prior HER2-targeted regimen

You may not qualify if:

• Patients meeting any of the following criteria will not be included in the study:
• Patients with evidence of other cancers six months prior to the mBC diagnosis date will be identified with the following International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) and International Classification of Diseases, 10th Revision, Clinical Modification (ICD-10-CM) codes in all databases: 140.xx - 195.xx, 200.xx - 208.xx, C00.xx - C76.xx, C81.xx - C96.xx. (exclude - ICD-9: 174.X, 175.X; ICD-10: C50.XX)
• Patients treated with tucatinib prior to T-DXd
• Patients participating in clinical trials
• Patients receiving concomitant endocrine therapy on index line

Sponsors & Collaborators

• Pfizer: lead

Study Sites (1)

Pfizer

New York, New York, 10001, United States

Location

Related Links

• To obtain contact information for a study center near you, click here.

MeSH Terms

Conditions

Breast Neoplasms

Interventions

tucatinib; Trastuzumab; Capecitabine

Condition Hierarchy (Ancestors)

Neoplasms by Site; Neoplasms; Breast Diseases; Skin Diseases; Skin and Connective Tissue Diseases

Intervention Hierarchy (Ancestors)

Antibodies, Monoclonal, Humanized; Antibodies, Monoclonal; Antibodies; Immunoglobulins; Immunoproteins; Blood Proteins; Proteins; Amino Acids, Peptides, and Proteins; Serum Globulins; Globulins; Deoxycytidine; Cytidine; Pyrimidine Nucleosides; Pyrimidines; Heterocyclic Compounds, 1-Ring; Heterocyclic Compounds; Fluorouracil; Uracil; Pyrimidinones; Deoxyribonucleosides; Nucleosides; Nucleic Acids, Nucleotides, and Nucleosides

Study Officials

• Pfizer CT.gov Call Center

  Pfizer

  STUDY DIRECTOR

Study Design

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

Study Record Dates

• First Submitted: April 29, 2025
• First Posted: May 7, 2025
• Study Start: May 7, 2025
• Primary Completion: September 25, 2025
• Study Completion: September 25, 2025
• Last Updated: January 9, 2026

Record last verified: 2026-01

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)