Metastatic HER2+ Advanced Breast CancerNCT06961331
Real World-clinical Outcomes of Tucatinib, Trastuzumab, and Capecitabine Following Trastuzumab Deruxtecan (T-DXd) for the Treatment of HER2-positive Metastatic Breast Cancer.
An observational study of Metastatic HER2+ Advanced Breast Cancer, run by Pfizer at 1 site in United States.
Trial 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… Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Metastatic HER2+ Advanced Breast Cancer
- What is being tested?
- Tucatinib, Trastuzumab and Capecitabine
- How many people
- 86 participants
- Where
- 1 siteUnited States
- Study dates
- 7 May 2025to 25 Sep 2025
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
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.
Who may be able to join
- Patients must meet all of the following inclusion criteria to be eligible for inclusion in the study:
- 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
Who cannot join
- 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
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Real-world Clinical Outcomes of Tucatinib, Trastuzumab, and Capecitabine Following Trastuzumab Deruxtecan for the Treatment of HER2-postive Metastatic Breast Cancer
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
- Being tested
- Tucatinib, Trastuzumab, Capecitabine
- Keywords
- her2+, mBC, metastatic breast cancer, tukysa, tucatinib, breast neoplasm, Human epidermal growth factor receptor 2 positive
- Medical subject headings
- Breast Neoplasms
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
TucatinibDrug
As provided in real world practice.
TrastuzumabDrug
As provided in real world practice.
CapecitabineDrug
As provided in real world practice.
| Study group | Role | What they receive |
|---|---|---|
| 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. Receives: Drug: Tucatinib; Drug: Trastuzumab; Drug: Capecitabine |
What is being measured
The primary outcome is the main question the study is designed to answer.
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.
Measured: 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.
Measured: 1 Year
Overall survival (OS)
OS will be defined as the time in months from initiation of therapy to death from any cause.
Measured: 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.
Measured: 1 Year
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted7 May 2025
- Study start7 May 2025
- Primary completion25 Sep 2025
- Study completion25 Sep 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Metastatic HER2+ Advanced Breast CancerStudies of the same condition, open and under way.
- More trials run by PfizerThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Other
- Time perspective
- Retrospective
- Enrolment
- 86 participants (actual)
Sponsor and investigators
- Lead sponsor
- Pfizer
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Pfizer CT.gov Call Center, Study director, Pfizer
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06961331
- Sponsor's protocol ID
- C4251025
- Status last verified
- Jan 2026
- First submitted
- 29 Apr 2025
- Last updated
- 9 Jan 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- Individual data sharing
- No: Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical\_trials/trial\_data\_and\_results/data\_requests.
Study at a glance
From the registry record, last updated by the sponsor on 9 Jan 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Real-world Clinical Outcomes of Tucatinib, Trastuzumab, and Capecitabine Following Trastuzumab Deruxtecan for the Treatment of HER2-postive Metastatic Breast Cancer
- ClinicalTrials.gov ID
- NCT06961331
- Acronym / sponsor ID
- C4251025
- Conditions
- Metastatic HER2+ Advanced Breast Cancer
- Keywords
- her2+, mBC, metastatic breast cancer, tukysa, tucatinib, breast neoplasm, Human epidermal growth factor receptor 2 positive
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 86 participants (actual)
- Lead sponsor
- PfizerIndustry (pharma, biotech, devices)
- Study start
- 7 May 2025 (actual)
- Primary completion
- 25 Sep 2025 (actual)
- Study completion
- 25 Sep 2025 (actual)
- First posted
- 7 May 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Study design
- Observational model
- Other
- Time perspective
- Retrospective
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| 3L+4L tucatinib triplet patients | – | Drug: Tucatinib, Drug: Trastuzumab, Drug: CapecitabineNon-interventional, retrospective cohort analysis of participants receiving the tucatinib triplet in the 3L or 4L setting immediately following T-DXd. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- 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.
Key inclusion criteria (6 listed)
- Patients must meet all of the following inclusion criteria to be eligible for inclusion in the study:
- 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.
Key exclusion criteria (5 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| TucatinibAs provided in real world practice. | Drug | 3L+4L tucatinib triplet patients |
| TrastuzumabAs provided in real world practice. | Drug | 3L+4L tucatinib triplet patients |
| CapecitabineAs provided in real world practice. | Drug | 3L+4L tucatinib triplet patients |
Primary outcome
Time to Next Treatment
Time frame: 1 Year
Time to next treatment defined as the time in months from the initiation of therapy to the initiation of subsequent LOT or death.
Time to Discontinuation
Time frame: 1 Year
Time to treatment discontinuation defined as the time in months from initiation of therapy to discontinuation for any reason or death.
Overall survival (OS)
Time frame: 1 Year
OS will be defined as the time in months from initiation of therapy to death from any cause.
real-world Progression free survival (rwPFS)
Time frame: 1 Year
rwPFS will be defined as time in months from initiation of therapy to progression or death from any cause.
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 9 Jan 2026.
- To obtain contact information for a study center near you, click here.Link provided by the sponsor.
- Individual participant dataSharing planned: No. Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical_trials/trial_data_and_results/data_requests.
Related trials for Metastatic HER2+ Advanced Breast Cancer
RecruitingPhase 1/2
Beamion BCGC-1: A Study to Find a Suitable Dose of Zongertinib Used Alone and in Combination With Other Treatments to Test Whether it Helps People With Different Types of HER2+ Cancer That Has Spread
Metastatic Breast Cancer, Metastatic Gastric Adenocarcinoma
Not yet recruitingPhase 1
A Study to Evaluate the Effects of GDC-4198 in Combination With Letrozole, Fulvestrant, or Giredestrant in Participants With Locally Advanced or Metastatic Hormone Receptor-Positive, HER2-Negatve Breast Cancer
Advanced or Metastatic Breast Cancer
RecruitingObservational study
A Study to Evaluate the Effectiveness and Safety of Inavolisib in Participants With Endocrine-resistant, PIK3CA-mutated, Hormone Receptor-positive, HER2-negative Locally Advanced or Metastatic Breast Cancer
Locally Advanced Breast Cancer, Metastatic Breast Cancer
RecruitingPhase 3
Phase 3 Study of RLY-2608 + Fulvestrant vs Capivasertib + Fulvestrant as Treatment for Locally Advanced or Metastatic PIK3CA-mutant HR+/HER2- Breast Cancer
PIK3CA Mutation, HER2- Negative Breast Cancer
RecruitingPhase 2/3
RO7771950 Versus Tucatinib in Combination With Trastuzumab and Capecitabine in People With Locally Advanced or Metastatic Breast Cancer That is Human Epidermal Growth Factor Receptor 2 (HER2)-Positive
HER2-positive Breast Cancer
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Pfizer CT.gov Call Center study director
Pfizer
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Metastatic HER2+ Advanced Breast Cancer, run by Pfizer at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 9 Jan 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Time to Next Treatment (time frame: 1 Year). The study lists 4 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 9 Jan 2026.