Actively Recruiting
A Vaccine (STEMVAC) With Standard Endocrine-Based Therapy or Chemotherapy for the Treatment of Metastatic Hormone Receptor Positive, HER2 Negative Breast Cancer
Led by University of Washington · Updated on 2026-04-06
40
Participants Needed
1
Research Sites
162 weeks
Total Duration
On this page
AI-Summary
What this Trial Is About
This phase II trial studies how well a vaccine, STEMVAC, works in combination with standard endocrine-based therapy (ET) with a CDK4/6 targeted drug therapy, or with the chemotherapy drug capecitabine, in treating patients with hormone receptor (HR)-positive, HER2-negative breast cancer that has spread from where it first started (primary site) to other places in the body (metastatic). STEMVAC is designed to target proteins that cancer cells use when they become more aggressive and start to spread, and it is believed to work by boosting the immune system to recognize and destroy the invader tumor cells that are causing the disease. Standard ET is treatment that adds, blocks, or removes hormones in order to slow or stop the growth of cancer. Standard CDK4/6 inhibitors, including abemaciclib, may stop the growth of tumor cells and may kill them by blocking some of the enzymes needed for cell growth. Capecitabine is in a class of medications called antimetabolites. It is taken up by tumor cells and breaks down into fluorouracil, a substance that kills tumor cells. Giving STEMVAC in combination with standard ET or chemotherapy may be an effective treatment for metastatic HR positive, HER2 negative breast cancer.
CONDITIONS
Official Title
A Vaccine (STEMVAC) With Standard Endocrine-Based Therapy or Chemotherapy for the Treatment of Metastatic Hormone Receptor Positive, HER2 Negative Breast Cancer
Who Can Participate
Eligibility Criteria
You may qualify if you...
- Patients must be at least �3e= 18 years of age
- Histologically confirmed hormone receptor positive metastatic breast cancer: Tumors positive for estrogen receptor (ER) and/or progesterone receptor (PR)
- HER2-negative or HER2-low breast cancer defined by immunohistochemistry or fluorescence in situ hybridization
- For Cohort 1: Receiving first or second line endocrine therapy with a CDK4/6 inhibitor and completed at least 2 cycles of CDK4/6 inhibitor
- For Cohort 2: Progressed on endocrine therapies and completed at least 1 cycle of capecitabine chemotherapy
- Eastern Cooperative Oncology Group (ECOG) Performance Status Score of 0 or 1
- Willing to undergo up to two biopsy procedures during the study
- Have at least one biopsy-accessible disease site confirmed by treating oncologist
- White blood cell count �3e= 2000/mm�b3 within 28 days before study vaccine
- Lymphocyte count �3e= 500/mm�b3 within 28 days before study vaccine
- Absolute neutrophil count �3e= 800/�b5L within 28 days before study vaccine
- Platelets �3e= 75,000/�b5L within 28 days before study vaccine
- Total bilirubin �3c= 1.5 times institutional upper limit of normal (ULN), except up to 3.0 mg/dL for Gilbert's syndrome patients within 28 days before study vaccine
- AST/ALT �3c= 3 times institutional ULN within 28 days before study vaccine
- Creatinine �3c= 2.0 mg/dL or creatinine clearance greater than 30 mL/min within 28 days before study vaccine
- Patients of childbearing potential must use dual contraception methods and have a negative pregnancy test at screening
- Patients must have recovered from major infections or surgeries and have no significant active illnesses preventing treatment
You will not qualify if you...
- Cardiac conditions including symptomatic restrictive or dilated cardiomyopathy, unstable angina within 4 months, NYHA class III-IV heart failure, symptomatic pericardial effusion, uncontrolled hypertension or arrhythmias
- Autoimmune diseases or comorbidities requiring chronic steroids or immunosuppressants
- Non-breast cancers needing radiation or systemic therapy within last 5 years
- Known allergy to GM-CSF or contraindications to GM-CSF
- Pregnant or breastfeeding
- Known HIV, hepatitis B, or hepatitis C infection
- Major surgery within 4 weeks before starting study vaccine
- Current use of immunosuppressive agents or systemic corticosteroids (some topical and inhalational corticosteroids allowed)
- Currently enrolled in another clinical trial with experimental therapy or devices (biomarker or non-interventional studies allowed)
- Less than 14 days between a non-study vaccine and STEMVAC vaccination (except tetanus and diphtheria vaccines)
- Any condition that would interfere with participation as judged by the oncologist
AI-Screening
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Trial Site Locations
Total: 1 location
1
Fred Hutch/University of Washington Cancer Consortium
Seattle, Washington, United States, 98109
Actively Recruiting
Research Team
R
Research Coordinator(s)
CONTACT
How is the study designed?
Study Type
INTERVENTIONAL
Masking
NONE
Allocation
NON_RANDOMIZED
Model
PARALLEL
Primary Purpose
TREATMENT
Number of Arms
2
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