NCT07078604

A Cancer Vaccine (STEMVAC) in Combination With Chemotherapy for the Treatment of PD-L1 Negative Metastatic Triple-Negative Breast Cancer

A Phase II Trial of the Immunogenicity of a DNA Plasmid-Based Vaccine (STEMVAC) Encoding Th1 Selective Epitopes From Five Antigens Associated With Breast Cancer Stem Cells (MDM2, YB1, SOX2, CDH3, CD105) in Patients With Metastatic Triple-Negative Breast Cancer

• Status: Recruiting
• Phase: Phase 2
• Study type: Interventional
• Enrollment: 20 (estimated)
• Sponsor: University of Washington · Academic / Other
• Sex: All
• Age: 18 Years
• Healthy volunteers: Not accepted

Summary

This phase II trial studies how well a cancer vaccine called STEMVAC works in combination with chemotherapy in treating patients with PD-L1 negative, triple-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 are expressed on breast cancer stem cells, and it is believed to work by boosting the immune system to recognize and destroy the invader tumor cells that are causing the disease. Chemotherapy drugs work in different ways to stop the growth of tumor cells, either by killing the cells, by stopping them from dividing, or by stopping them from spreading. Giving STEMVAC in combination with chemotherapy may be an effective treatment for PD-L1 negative metastatic triple-negative breast cancer.

Detailed description

OUTLINE: Patients receive systemic standard of care chemotherapy as determined by their attending medical oncologist. Patients receive 3 priming doses of STEMVAC with sargramostim intradermally (ID) every 21-28 days (7-13 days after each chemotherapy administration or during the off week of weekly chemotherapy), 2 booster STEMVAC/sargramostim doses at 4 and 7 months after 3rd priming dose, and then every 6 months in the absence of disease progression or unacceptable toxicity. Patients also undergo computed tomography (CT) or ultrasound-guided biopsy, for research purposes, on study, as well as CT or positron emission tomography (PET) scans and blood sample collection throughout the study. In addition, patients may also undergo CT or ultrasound-guided biopsy, for research purposes, during screening. After completion of study treatment, patients are followed up at 21 or 28 days and then every 6 months for 3 years.

Conditions

• Anatomic Stage IV Breast Cancer AJCC v8
• Metastatic Triple-Negative Breast Carcinoma

Interventions

Type	Name	Description
BIOLOGICAL	CD105/Yb-1/SOX2/CDH3/MDM2-polyepitope Plasmid DNA Vaccine	Given ID
DRUG	Chemotherapy	Given standard of care chemotherapy
PROCEDURE	Computed Tomography	Undergo CT scans
PROCEDURE	Computed Tomography Assisted Biopsy	Undergo CT-guided biopsy
BIOLOGICAL	Sargramostim	Given ID
PROCEDURE	Ultrasound-Guided Biopsy	Undergo ultrasound-guided biopsy
PROCEDURE	Biospecimen Collection	Undergo blood sample collection
PROCEDURE	Positron Emission Tomography (PET)	Undergo PET scan

Timeline

• Start date: 2026-03-20
• Primary completion: 2027-04-30
• Completion: 2028-06-30
• First posted: 2025-07-22
• Last updated: 2026-04-07

Locations

1 site across 1 country: United States

Regulatory

• FDA-regulated drug study