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Converting HR+ Breast Cancer Into an Individualized Vaccine

This study is for post-menopausal women with newly diagnosed stage II-III hormone receptor-positive (HR+), HER2-negative (HER2-) breast cancer. It's testing if combining radiation therapy (Focal Radiation therapy) with immunotherapy drugs like pembrolizumab and/or CDX-301 (Flt-3 ligand) can improve treatment outcomes when given alongside standard hormone therapy (letrozole). Researchers want to see if these combinations are safe (tolerability) and how well they shrink tumors (clinical and pathological response rate). The study aims to enroll 100 participants.

Study design
This is a randomized interventional study, meaning you would be assigned by chance to one of four treatment groups. It plans to enroll 100 participants.
What's involved
You would be on the study for a total of 5 months, including 4 months of active treatment with breast surgery at week 16, and then one month of follow-up after surgery.
Compensation
Not stated in the trial record.
Follow-up
Your tolerability, clinical response, and pathological response will be measured for up to 3 years.

AI-generated from the public study record. Only the study team can confirm whether you're eligible — confirm details with them before making decisions.

NCT03804944

Converting HR+ Breast Cancer Into an Individualized Vaccine

Recruiting
PHASE2Ages 18–90InterventionalTreatment
Weill Medical College of Cornell University
~100 participants
Updated 2026-01-28 on ClinicalTrials.gov
What's tested:Focal Radiation therapyPembrolizumab (200mg IV for 30 minutesCDX-301

At a glance

Recruiting sites
5 of 8 listed sites are recruiting right now
RecruitingSuspended, closed, or not yet open
What they're measuring
Tolerability will be demonstrated if no grade 3 or higher toxicities are observed in the first 8 patients, of each arm.
Measured over 3 years
+2 more outcomes measured

Conditions

Breast Cancer

Explore related trials

Breast Carcinoma

Where it's being run

8 sites across 4 states
New York4
Texas2
California1
Pennsylvania1

Study leadership

  • Silvia Formenti, M.D. · PRINCIPAL_INVESTIGATOR · Weill Cornell Medicine - New York Presbyterian Hospital

Who to contact

Fabiana Gregucci, M.D.
[email protected]
646 962-3110
Email the study team

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Do you actually qualify for this trial?

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Eligibility criteria

Inclusion

Post-menopausal female ≥ 18 years of age (Post-menopausal status defined as either 1) at least 2 years without menstrual period or 2) or patients older than 50 with serological evidence of post-menopausal status or 3) hysterectomized patients of any age with FSH confirmation of post-menopausal status.
Eastern Cooperative Oncology Group (ECOG) performance status 0-1
Biopsy proven diagnosis of ER+ PR+ or PR- HER2- breast cancer.
Clinical stage I(\>1.5cm, if N0) - III breast cancer, as per AJCC staging 8th edition.
Patient needs to be able to understand and demonstrate willingness to sign a written informed consent document.

Exclusion

Active connective tissue disorders, such as lupus or scleroderma requiring flare therapy
Current use of systemic chemotherapy, endoctine therap or HER2-neu targeted therapy
Post surgical excision of breast cancer.
Previous radiotherapy of the same breast.
Has received prior therapy with an anti-PD-1, anti-PD-L1, or anti-PD-L2 agent or with an agent directed to another stimulatory or co-inhibitory T-cell receptor (eg, CTLA-4, OX-40, CD137).
Inability to obtain histologic proof of breast cancer
Has received a live vaccine within 30 days prior to the first dose of study drug.
Is currently participating in or has participated in a study of an investigational agent or has used an investigational device within 4 weeks prior to the first dose of study treatment. Note: Participants who have entered the follow-up phase of an investigational study may participate as long as it has been 4 weeks after the last dose of the previous investigational agent.
Has a diagnosis of immunodeficiency or is receiving chronic systemic steroid therapy (in dosing exceeding 10 mg daily of prednisone equivalent) or any other form of immunosuppressive therapy within 7 days prior to the first dose of study drug.
Has a known additional malignancy (second primary) that is progressing or has required active treatment within the past 3 years. Note: Participants with basal cell carcinoma of the skin, squamous cell carcinoma of the skin, or carcinoma in situ (e.g. cervical cancer in situ) that have undergone potentially curative therapy are not excluded.
Has severe hypersensitivity (≥Grade 3) to pembrolizumab and/or any of its excipients.
Has active autoimmune disease that has required systemic treatment in the past 2 years (i.e. with use of disease modifying agents, corticosteroids or immunosuppressive drugs). Replacement therapy (eg., thyroxine, insulin, or physiologic corticosteroid replacement therapy for adrenal or pituitary insufficiency, etc.) is not considered a form of systemic treatment.
Has a history of (non-infectious) pneumonitis that required steroids or has current pneumonitis.
Has an active infection requiring systemic therapy.Has a known history of Human Immunodeficiency Virus (HIV). Note: No HIV testing is required unless mandated by local health authority.
Has a known history of Hepatitis B (defined as Hepatitis B surface antigen \[HBsAg\] reactive) or known active Hepatitis C virus (defined as HCV RNA \[qualitative\] is detected) infection. Note: no testing for Hepatitis B and Hepatitis C is required unless mandated by local health authority.
Has a known history of active TB (Bacillus Tuberculosis). Note: optional based on country.
Has known psychiatric or substance abuse disorders that would interfere with cooperation with the requirements of the trial.

What this trial measures

  • Tolerability will be demonstrated if no grade 3 or higher toxicities are observed in the first 8 patients, of each arm.3 years

    Tolerability of adding immunotherapy to a combination of tumor radiotherapy and endocrine therapy in the neoadjuvant setting of newly diagnosed HR+ breast cancer patients will be assessed if no grade 3 or higher toxicities are observed in the first 8 patients of each arm. CTCAE version 5.0 will be used.

  • Clinical response rate to tumor radiation +/-immunotherapy during standard endocrine therapy for HR+ breast cancer will be measured.3 years

    Clinical response rate to tumor radiation +/-immunotherapy during standard endocrine therapy for HR+ breast cancer will be measured.

  • Pathological response rate to tumor radiation +/-immunotherapy during standard endocrine therapy for HR+ breast cancer will be measured.3 years

    Pathological response rate to tumor radiation +/-immunotherapy during standard endocrine therapy for HR+ breast cancer will be measured.