A Vaccine (STEMVAC) for Improving Survival in Patients With Triple-Negative Breast Cancer and Moderate or Extensive Residual Cancer Burden

NCT07721259 | Not Yet Recruiting Phase 2 DMC FDA Drug

• 2 other identifiers: RG1126489NCI-2026-04722
• Study Type: interventional
• Target: 60
• Locations: 1 country
• Sites: 1

Brief Summary

This phase II trial evaluates whether a multi-antigen vaccine called STEMVAC improves disease-free survival after surgery in patients with triple-negative breast cancer (TNBC) and moderate or extensive residual cancer burden. TNBC has an aggressive clinical course and poorer disease-free survival compared to other subtypes. While patients who have no remaining tumor in the breast or lymph nodes after surgery have excellent long-term outcomes, patients with moderate or extensive residual cancer burden remain at high risk for early disease return and poorer prognosis. STEMVAC is designed to target proteins that tumor 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. Giving STEMVAC after surgery may improve disease-free survival rates in TNBC patients with moderate or extensive residual cancer burden.

Conditions

Triple-Negative Breast Carcinoma; Anatomic Stage I Breast Cancer AJCC v8; Anatomic Stage II Breast Cancer AJCC v8; Anatomic Stage III Breast Cancer AJCC v8

Outcome Measures

Primary Outcomes (2)

• Invasive breast cancer free survival (IBCFS)

  Kaplan-Meier curves will be generated with median estimation and 95% confidence interval, and log-rank tests will be conducted to compare the survival difference between groups. Will calculate the 3-year IBCFS rate with a 95% confidence interval from Kaplan-Meier methods using Greenwood standard errors.

  Time from randomization to local or distant recurrence or death, assessed up to 3 years

• Dynamics and characteristics of circulating tumor deoxyribonucleic acid (ctDNA)

  Through serial ctDNA evaluation, each sample will be assessed for ctDNA detectability and, if detectable, total ctDNA mass (continuous variable, as reported by the assay platform) will be calculated. ctDNA detectability and quantitative ctDNA measures will be summarized descriptively by timepoint and study arm, and changes over time will be evaluated using methods appropriate to the final endpoint definition, data distribution, and repeated-measures structure of the data. Associations with IBCFS will also be explored. Copy number variants (including aneuploidy, chromosome-level gains, losses, and amplifications, as defined by the final assay methodology) will also be tracked and tabulated, and changes over time will be evaluated descriptively in both study arms.

  Up to 3 weeks after last vaccination

Secondary Outcomes (3)

• Incidence of adverse events

  Up to 3 weeks after last vaccination

• Immune response

  Up to 3 weeks after last vaccination

• Expression of epithelial to mesenchymal transformation (EMT)-associated genes

  Archival tissue is collected after enrollment, within 30 days of baseline visit

Study Arms (2)

Arm A (STEMVAC, GM-CSF)

EXPERIMENTAL

Patients receive STEMVAC with GM-CSF ID every 3 weeks for 3 doses. Patients then receive booster vaccines ID 9 weeks after vaccine 3 and 18 weeks after booster 1. Patients also undergo collection of blood samples throughout the trial.

Biological: CD105/Yb-1/SOX2/CDH3/MDM2-polyepitope Plasmid DNA Vaccine; Drug: Recombinant Granulocyte-Macrophage Colony-Stimulating Factor; Procedure: Biospecimen Collection

Arm B (GM-CSF)

ACTIVE COMPARATOR

Patients receive GM-CSF ID every 3 weeks for 3 doses. Patients then receive booster vaccines ID 9 weeks after vaccine 3 and 18 weeks after booster 1. Patients also undergo collection of blood samples throughout the trial.

Drug: Recombinant Granulocyte-Macrophage Colony-Stimulating Factor; Procedure: Biospecimen Collection

Interventions

CD105/Yb-1/SOX2/CDH3/MDM2-polyepitope Plasmid DNA Vaccine BIOLOGICAL

Given ID

Also known as: CD105/Yb-1/SOX2/CDH3/MDM2 Plasmid Vaccine, STEMVAC, STEMVAC Th1 Polyepitope Plasmid-based Vaccine

Arm A (STEMVAC, GM-CSF)

Biospecimen Collection PROCEDURE

Undergo collection of blood samples

Also known as: Biological Sample Collection, Biospecimen Collected, Sample Collection, Specimen Collection

Arm A (STEMVAC, GM-CSF); Arm B (GM-CSF)

Recombinant Granulocyte-Macrophage Colony-Stimulating Factor DRUG

Given ID

Also known as: Colony-Stimulating Factor, Granulocyte-Macrophage, CSF 39300, CSF 39300/GM-CSF, CSF-GM (Hoechst), GM CSF, GM-CSF, GM-CSF (Schering), GMCSF, Recombinanr Colony-Stimulating Factor 2, Recombinant Colony-Stimulating Factor 2

Arm A (STEMVAC, GM-CSF); Arm B (GM-CSF)

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• At least 18 years of age
• Eastern Cooperative Oncology Group (ECOG) performance status score of ≤ 2
• Triple-negative breast cancer as determined by the treating oncologist
• Completed standard of care neoadjuvant chemotherapy in the opinion of their treating oncologist
• Patients whose tumors progress on neoadjuvant therapy may be enrolled
• No clinical evidence of local or distant recurrence
• Plan to receive standard of care adjuvant directed therapy
• Completed standard of care locoregional treatment, including definitive breast and lymph node surgery followed by standard radiation therapy, if recommended
• Residual cancer burden (RCB) index 2 or 3 as calculated per routine anatomic pathology clinical standards
• Absolute neutrophil count (ANC) ≥ 800/μL (within 30 days of first study vaccine administration)
• Hemoglobin (Hgb) ≥ 8 g/dL (within 30 days of first study vaccine administration)
• Platelets ≥ 75,000/ μL (within 30 days of first study vaccine administration)
• Total bilirubin ≤ 1.5 x institutional upper limit of normal (ULN), except patients with Gilbert's syndrome, in whom total bilirubin must be \< 3.0 mg/dL (within 30 days of first study vaccine administration)
• Aspartate aminotransferase (AST)/alanine aminotransferase (ALT) ≤ 1.5 x institutional ULN (within 30 days of first study vaccine administration)
• Creatinine ≤ 1.5 x ULN mg/dL or creatinine clearance \> 60 mL/min (within 30 days of first study vaccine administration)

You may not qualify if:

• Toxicities related to prior exposure to immune checkpoint inhibitors for which immune checkpoint inhibitors cannot be safely continued as determined by study investigator
• Germline BRCA1 or BRCA2 mutations with adjuvant olaparib planned within the study period
• NOTE: If olaparib is not planned, then these patients are eligible
• Any known cardiac conditions:
• Symptomatic restrictive cardiomyopathy
• Dilated cardiomyopathy
• Unstable angina within 4 months prior to enrollment
• New York Heart Association functional class III-IV heart failure on active treatment
• Symptomatic pericardial effusion
• Autoimmune disease requiring active systemic treatment
• Known hypersensitivity reaction to the GM-CSF adjuvant; any known contra-indication to GM-CSF
• Pregnant or breast feeding
• Known history of human immunodeficiency virus (HIV) infection, hepatitis B (e.g., hepatitis B virus surface antigen \[HBsAg\] reactive), or hepatitis C (e.g., hepatitis C virus \[HCV\] ribonucleic acid \[RNA\] is detected)
• Major surgery within the 4 weeks prior to initiation of first study vaccine
• Enrollment in any other clinical protocol or investigational trial that involves concurrent administration of experimental therapy and/or therapeutic devices, or investigational drug. Patients who completed prior clinical trials (such as neoadjuvant treatment, surgery or radiation trials) and are on long term follow up are permitted

Sponsors & Collaborators

• University of Washington: lead
• United States Department of Defense: collaborator

Study Sites (1)

Fred Hutch/University of Washington Cancer Consortium

Seattle, Washington, 98109, United States

Location

MeSH Terms

Conditions

Triple Negative Breast Neoplasms

Interventions

Granulocyte-Macrophage Colony-Stimulating Factor; Colony-Stimulating Factors; Specimen Handling

Condition Hierarchy (Ancestors)

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

Intervention Hierarchy (Ancestors)

Glycoproteins; Glycoconjugates; Carbohydrates; Hematopoietic Cell Growth Factors; Cytokines; Intercellular Signaling Peptides and Proteins; Peptides; Amino Acids, Peptides, and Proteins; Proteins; Biological Factors; Clinical Laboratory Techniques; Diagnostic Techniques and Procedures; Diagnosis; Investigative Techniques

Study Officials

• Natasha Hunter, MD

  Fred Hutch/University of Washington Cancer Consortium

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Research Coordinator(s)

CONTACT

866-932-8588; cvitrial@uw.edu

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: July 17, 2026
• First Posted: July 23, 2026
• Study Start (Estimated): September 30, 2026
• Primary Completion (Estimated): July 16, 2029
• Study Completion (Estimated): July 16, 2030
• Last Updated: July 23, 2026

Record last verified: 2026-07

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)