Could your own tumor become a vaccine? new trial aims to train the immune system against breast cancer

NCT ID NCT03804944

Recruiting now Disease control Sponsor: Weill Medical College of Cornell University Source: ClinicalTrials.gov ↗

First seen Jun 25, 2026 · Last updated Jun 27, 2026 · Updated 1 time

Summary

This phase 2 trial is testing a new approach for post-menopausal women with HR+HER2- breast cancer. Participants receive standard hormone therapy plus focal radiation, and some also get the immunotherapy drug pembrolizumab and an immune booster (CDX-301). The goal is to see if this combination can turn the tumor into a personalized vaccine that triggers a stronger immune response. The study will check for safety and measure how well the tumor shrinks or disappears before surgery.

What this could mean

Our plain-language read of the trial. This is informational only — not medical advice or a prediction.

Active substance: Pembrolizumab (immunotherapy drug) and CDX-301 (immune booster), combined with focal radiation therapy
What this could lead to: If successful, this approach could turn a patient's own tumor into a vaccine that helps the immune system fight the cancer more effectively, potentially improving outcomes for HR+ breast cancer.
What could go wrong: This is a small, early-phase trial (100 participants) testing safety and initial effectiveness. The combination may cause side effects, and it's unknown if it will work better than standard treatment.

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Conditions

The condition(s) this trial relates to.

breast cancer breast neoplasm hormone receptor-positive breast cancer

As listed by the trial registrant

The condition terms exactly as the trial's registrant entered them.

BREAST CANCER

Contacts and locations

Locations

Brooklyn Methodist Hospital - NewYork Presbyterian
RECRUITING

New York, New York, 11215, United States
Cedars-Sinai Medical Center
WITHDRAWN

Los Angeles, California, 90048, United States
Houston Methodist Cancer Center
RECRUITING

Houston, Texas, 77030, United States
Icahn School of Medicine at Mt Sinai
WITHDRAWN

New York, New York, 10027, United States
New York Presbyterian Hospital - Queens
RECRUITING

New York, New York, 10065, United States
UPMC Hillman Cancer Center
WITHDRAWN

Pittsburgh, Pennsylvania, 15232, United States
UT Southwestern Medical Center
RECRUITING

Dallas, Texas, 75390-9179, United States
Weill Cornell Medicine New York Presbyterian Hospital
RECRUITING

New York, New York, 10065, United States

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