Personalized Cancer Vaccine (PCV) Strategy in Triple Negative Breast Cancer Patients

September 3, 2026 updated by: Washington University School of Medicine

Phase 1 Clinical Trial of a Personalized Cancer Vaccine (PCV) Strategy +/- AB248 (CD8-selective IL-2 Mutein Fusion Protein) in Patients With a New Diagnosis of Triple Negative Breast Cancer Undergoing Neoadjuvant Chemoimmunotherapy

This is a phase 1 clinical trial to evaluate the safety, feasibility and immunogenicity of a personalized cancer vaccine (PCV) strategy with or without CD8-selective IL-2 mutein fusion protein in patients with triple negative breast cancer undergoing neoadjuvant chemoimmunotherapy.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

30

Phase

  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

  • United States
    • Missouri
      • St Louis, Missouri, United States, 63110
        • Washington University School of Medicine
        • Principal Investigator:
          • Katherine Clifton, MD
        • Contact:
        • Principal Investigator:
          • William Gillanders, MD
        • Sub-Investigator:
          • Malachi Griffith, PhD
        • Sub-Investigator:
          • Obi Griffith, PhD
        • Sub-Investigator:
          • Cynthia Ma, MD, PhD
        • Sub-Investigator:
          • Robert Schreiber, PhD
        • Sub-Investigator:
          • Feng Gao, MD, PhD, MPH
        • Sub-Investigator:
          • Peter Goedegebuure, PhD
        • Sub-Investigator:
          • Lijin Li, PhD
        • Sub-Investigator:
          • Sherri Davies, PhD
        • Contact:
        • Sub-Investigator:
          • Ian Hagemann, MD, PhD

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Step 0 Inclusion Criteria:

  • Newly diagnosed, previously untreated, locally advanced non-metastatic triple negative breast cancer (as defined by the most recent ASCO/CAP guidelines). Permissible staging per AJCC is as follows:

    • T1c, N1-N2
    • T2, N0-N2
    • T3, N0-N2
  • At least 18 years of age.
  • Adequate tissue available for nucleic acid isolation/PCV design or willing to undergo biopsy if adequate tissue is not available.
  • Adequate cardiac function per treating physician and a candidate for the KEYNOTE 522 regimen (or receiving the KEYNOTE 522 regimen for no more than one month). Note that patients who are already receiving the KEYNOTE 522 regimen at the time of screening must have adequate archival tissue for nucleic acid isolation/PCV design (biopsy will not be permitted).
  • TIL percentage < 10% (performed on SOC biopsy).
  • Ability to understand and willingness to sign an IRB approved written informed consent document. Legally authorized representatives may sign and give informed consent on behalf of study participants.

Step 0 Exclusion Criteria:

  • Prior or concurrent malignancy whose natural history has the potential to interfere with the safety or efficacy assessment of the investigational regimen. Patients with prior or concurrent malignancy that does NOT meet that definition are eligible for this trial.
  • Received prior chemotherapy, targeted therapy, or radiation therapy within the past 12 months.
  • Received prior therapy with an anti-PD-1, anti-PD-L1, or anti-PD-L2 agent, or with an agent directed to another co-inhibitory T-cell receptor.
  • Currently receiving any other investigational agents.
  • A history of allergic reactions attributed to compounds of similar chemical or biologic composition to any agents used in the study.
  • Received a live vaccine within 30 days of the first dose of pembrolizumab.
  • Active autoimmune disease that has required systemic treatment in the past 2 years.
  • Diagnosis of immunodeficiency or receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of pembrolizumab.
  • History of (non-infectious) pneumonitis that required steroids, or current pneumonitis.
  • Uncontrolled intercurrent illness including, but not limited to: ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, or cardiac arrhythmia. Patients with a known history or current symptoms of cardiac disease, or history of treatment with cardiotoxic agents, should have a clinical risk assessment of cardiac function using the New York Heart Association Function Classification; to be eligible for this trial, patients should be a class 2B or better.
  • Pregnant and/or breastfeeding. Women of childbearing potential must have a negative pregnancy test within 7 days of study entry.
  • Known history of active TB (bacillus tuberculosis).
  • Known history of HIV.
  • Evidence of chronic hepatitis B virus (HBV) that is detectable on suppressive therapy. Patients with evidence of chronic HBV infection with undetectable HBV viral load on suppressive therapy are eligible. HBV testing not required in the absence of known history of infection.
  • History of hepatitis C virus (HCV) infection that has not been cured or that has a detectable viral load. Patients with a history of HCV that has been treated and cured are eligible. Patients with HCV infection who are currently on treatment and have an undetectable HCV viral load are eligible. HCV testing not required in the absence of known history of infection.

Step 1 Inclusion Criteria:

  • ECOG performance status ≤ 1 within 10 days of initiation of PCV

  • Adequate bone marrow and organ function within 28 days of initiation of PCV as defined below:

    • Absolute neutrophil count ≥ 1.0 K/cumm
    • Platelets ≥ 100 K/cumm
    • Hemoglobin ≥ 8.0 g/dL
    • Total bilirubin ≤ 1.5 x IULN
    • AST(SGOT)/ALT(SGPT) ≤ 3.0 x IULN
    • Creatinine clearance > 30 mL/min by Cockcroft-Gault
  • The effects of the PCV on the developing human fetus are unknown. For this reason, women of childbearing potential and men must agree to use adequate contraception prior to study entry, for the duration of study participation, and for 6 months after last dose of PCV. Should a woman become pregnant or suspect she is pregnant while participating in this study or should a man suspect he has fathered a child, s/he must inform her treating physician immediately.
  • Received at least 4 months of the KEYNOTE 522 regimen.

Step 1 Exclusion Criteria:

  • Currently receiving any other investigational agents.
  • Pregnant and/or breastfeeding.
  • Experiencing ongoing AEs related to the SOC KEYNOTE 522 regimen that have not resolved to < grade 3. Patients may be permitted to enroll with a grade 3 AE with approval of the PI and treating physician.
  • QTcF > 470 msec.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Arm 1: Neoadjuvant SOC KEYNOTE 522 + Adjuvant PCV + Pembrolizumab
Patients will be treated with standard of care (SOC) neoadjuvant chemoimmunotherapy according to the KEYNOTE 522 regimen. Approximately 2 weeks after the conclusion of SOC neoadjuvant therapy but prior to SOC surgery, patients will start the personalized cancer vaccine (PCV). Patients will receive 5 doses of the PCV + poly-ICLC on Days 1, 4, 8, 15, and 22. Patients will undergo the SOC surgery on Day 29 +/- 5 days. Following surgery, patients will receive 3 additional doses of the PCV + poly-ICLC on days 43, 64, and 85 along with SOC adjuvant pembrolizumab.
Other: pVAC tools neoantigen prediction algorithm
The pVACtools suite of software tools will be used to identify and prioritize cancer neoantigens based on neoantigen identification algorithms.
Drug: Paclitaxel
As part of the KEYNOTE 522 Regimen, given per standard of care.
Other Names:
  • Taxol
  • Onxol
Drug: Carboplatin
As part of the KEYNOTE 522 Regimen, given per standard of care.
Other Names:
  • Paraplatin
  • KYXATA
Drug: Pembrolizumab
As a part of the KEYNOTE 522 Regimen, given per standard of care. Adjuvant pembrolizumab will be given per standard of care.
Other Names:
  • Keytruda
Drug: Doxorubicin
As part of the KEYNOTE 522 Regimen, given per standard of care.
Other Names:
  • Adriamycin
  • Adriamycin PFS
  • Adriamycin RDF
  • Rubex
Drug: Cyclophosphamide
As part of the KEYNOTE 522 Regimen, given per standard of care.
Other Names:
  • Cytoxan
  • Neosar
  • Frindovyx
Biological: Personalized cancer vaccine (PCV)
PCV is given intra-muscular (IM). Each PCV will consists of up to 4 separate injections, with each syringe containing peptides from one of the up to four peptide pools combined with adjuvant poly-ICLC.
Other Names:
  • CD8-selective IL-2 mutein fusion protein
Drug: poly-ICLC
Poly-ICLC is mixed with the personalized cancer vaccine (PCV). The PCV is given intramuscularly (IM) at 1mg dose.
Experimental: Arm 2: Neoadjuvant SOC KEYNOTE 522 + Adjuvant PCV + Pembrolizumab+AB248
Patients will be treated with standard of care (SOC) neoadjuvant chemoimmunotherapy according to the KEYNOTE 522 regimen. Approximately 2 weeks after the conclusion of SOC neoadjuvant therapy but prior to SOC surgery, patients will start the personalized cancer vaccine (PCV). Patients will receive 5 doses of the PCV + poly-ICLC on Days 1, 4, 8, 15, and 22. Patients will also receive 2 doses of AB248. Patients will undergo the SOC surgery on Day 29 +/- 5 days. Following surgery, patients will receive 3 additional doses of the PCV + poly-ICLC on days 43, 64, and 85 along with SOC adjuvant pembrolizumab.
Other: pVAC tools neoantigen prediction algorithm
The pVACtools suite of software tools will be used to identify and prioritize cancer neoantigens based on neoantigen identification algorithms.
Drug: Paclitaxel
As part of the KEYNOTE 522 Regimen, given per standard of care.
Other Names:
  • Taxol
  • Onxol
Drug: Carboplatin
As part of the KEYNOTE 522 Regimen, given per standard of care.
Other Names:
  • Paraplatin
  • KYXATA
Drug: Pembrolizumab
As a part of the KEYNOTE 522 Regimen, given per standard of care. Adjuvant pembrolizumab will be given per standard of care.
Other Names:
  • Keytruda
Drug: Doxorubicin
As part of the KEYNOTE 522 Regimen, given per standard of care.
Other Names:
  • Adriamycin
  • Adriamycin PFS
  • Adriamycin RDF
  • Rubex
Drug: Cyclophosphamide
As part of the KEYNOTE 522 Regimen, given per standard of care.
Other Names:
  • Cytoxan
  • Neosar
  • Frindovyx
Biological: Personalized cancer vaccine (PCV)
PCV is given intra-muscular (IM). Each PCV will consists of up to 4 separate injections, with each syringe containing peptides from one of the up to four peptide pools combined with adjuvant poly-ICLC.
Other Names:
  • CD8-selective IL-2 mutein fusion protein
Drug: poly-ICLC
Poly-ICLC is mixed with the personalized cancer vaccine (PCV). The PCV is given intramuscularly (IM) at 1mg dose.
Drug: AB248
AB248 is given intravenously (IV) over 30 minutes at the recommended dose.
Other Names:
  • CD8-selective IL-2 mutein fusion protein
  • Etakafusp alfa

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Feasibility as determined by number of enrolled patients with triple negative breast cancer
Time Frame: Completion of enrollment (1 day for patient)
Defined as enrolling 24 evaluable patients in 36 months.
Completion of enrollment (1 day for patient)
Treatment-emergent adverse events (TEAEs)
Time Frame: Step 1 enrollment to 30 days after completion of PCV treatment (estimated time of 115 days)
Treatment-emergent adverse events (TEAEs) will be assessed via CTCAE v6.
Step 1 enrollment to 30 days after completion of PCV treatment (estimated time of 115 days)
Treatment-related adverse events (TRAEs)
Time Frame: Step 1 enrollment to 30 days after completion of PCV treatment (estimated time of 115 days)
Treatment-related adverse events (TRAEs) will be assessed via CTCAE v6.
Step 1 enrollment to 30 days after completion of PCV treatment (estimated time of 115 days)
Serious adverse events (SAEs)
Time Frame: Step 1 enrollment to 30 days after completion of PCV treatment (estimated time of 115 days)
Serious adverse events (SAEs) will be assessed via CTCAE v6.
Step 1 enrollment to 30 days after completion of PCV treatment (estimated time of 115 days)
Feasibility as determined by time required for PCV design and manufacture
Time Frame: Start of Step 0 Enrollment to PCV completion (estimated time of 24 weeks)
Defined as completion of design and manufacture within 24 weeks.
Start of Step 0 Enrollment to PCV completion (estimated time of 24 weeks)
Feasibility as determined by rate of successful PCV delivery
Time Frame: Day 1
Defined as at least 70% of patients receiving at least one dose of PCV.
Day 1

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Recurrence-free survival (RFS)
Time Frame: Step 1 enrollment through completion of follow up (estimated time of 5 years and 85 days)
Recurrence-free survival is defined as the rate of disease recurrence from Step 1 enrollment until disease recurrence per standard of care assessments or until patient is off study, whichever occurs first.
Step 1 enrollment through completion of follow up (estimated time of 5 years and 85 days)
Immune response as evaluated by ELISPOT analysis.
Time Frame: Step 0 Enrollment to 12 months after PCV completion (estimated time of 18 months and 85 days)
Samples will be drawn at Step 0 enrollment, day 1, day 15, day 22, day of surgery, day 43, day 64, day 85, and patients randomized to Arm 2 will have an optional draw at Year 1 follow-up.
Step 0 Enrollment to 12 months after PCV completion (estimated time of 18 months and 85 days)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Washington University School of Medicine

Investigators

  • Principal Investigator: William Gillanders, MD, Washington University School of Medicine

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

October 1, 2026

Primary Completion (Estimated)

July 31, 2030

Study Completion (Estimated)

June 30, 2035

Study Registration Dates

First Submitted

December 9, 2025

First Submitted That Met QC Criteria

December 9, 2025

First Posted (Actual)

December 23, 2025

Study Record Updates

Last Update Posted (Actual)

September 4, 2026

Last Update Submitted That Met QC Criteria

September 3, 2026

Last Verified

September 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 202604114

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

Yes

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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