Combining radiation boost with immune therapy for breast cancer

Preoperative Use of Radiation Boost to Enhance Effectiveness of Immune Checkpoint Blockade Therapy in Operable Breast Cancer

Phase1; Phase2 Interventional Abramson Cancer Center at Penn Medicine · NCT04454528

This study is testing if combining a special immune therapy with a single dose of radiation can help people with early breast cancer do better than with standard treatment.

Quick facts

PhasePhase1; Phase2
Study typeInterventional
Enrollment27 (estimated)
Ages18 Years and up
SexAll
SponsorAbramson Cancer Center at Penn Medicine Academic / other
Drugs / interventionspembrolizumab, chemotherapy, radiation
Locations1 site (Philadelphia, Pennsylvania)
Trial IDNCT04454528 on ClinicalTrials.gov

What this trial studies

This study aims to evaluate the feasibility of combining pembrolizumab, an immune checkpoint inhibitor, with a single fraction radiation boost in patients with early operable breast cancer. It consists of four arms, with different sequences of treatment administration and a control arm receiving standard care. The study will assess clinical responses through imaging and histology exams, as well as immune responses by analyzing blood and tissue samples for specific immune cell changes. A minimum of 27 participants will be enrolled to determine the effectiveness of this combined approach.

Who should consider this trial

Good fit: Ideal candidates include adults with newly diagnosed breast cancer, particularly those with specific subtypes like triple-negative or certain hormone receptor-positive cancers.

Not a fit: Patients with larger tumors or those who are not eligible for the specified breast cancer subtypes may not benefit from this study.

Why it matters

Potential benefit: If successful, this approach could enhance the effectiveness of immune therapy in treating early-stage breast cancer.

How similar studies have performed: Other studies have shown promise in combining radiation with immune therapies, suggesting potential for success in this novel approach.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

Men and women age ≥ 18 years old (unless otherwise specified) Willing and able to provide written informed consent/assent ECOG Performance Status 0 - 1

Patients with:

Newly diagnosed breast cancer with tumor size \< 5 cm who are not eligible for I-SPY2 (to prevent recruitment competition), or not recommended to undergo standard of care neoadjuvant chemotherapy with at least one of the following features:

* Triple negative breast cancer (TNBC) defined using the ASCO CAP guidelines with the following modification supported by a recent publication as ER ≤ 10%, PR ≤ 10%, HER2- determined by immunohistochemistry and/or fluorescence in situ hybridization analyses and with tumor size ≤ 2.5 cm;
* HR+ HER2- breast cancer regardless of nodal status and age of diagnosis ≥ 50
* HR+ HER2- breast cancer and age of diagnosis \<50 with tumor size ≤ 2.5 cm and clinically node (+)
* HR+ or HR- and HER2+ breast cancer with tumor size ≤ 2.5 cm
* Ductal carcinoma in situ (DCIS) with microinvasion

OR

* Locally recurrent breast cancer of any receptor subtype with no prior radiation, not recommended to receive neoadjuvant chemotherapy and expecting surgical excision as part of treatment.

A female participant is eligible to participate if she is not pregnant, not breastfeeding, and at least one of the following conditions applies:

1. Not a woman of childbearing potential (WOCBP) as defined in Appendix 2 of the study protocol OR
2. A WOCBP who agrees to follow the contraceptive guidance in Appendix 2 during the treatment period and for at least 120 days for study treatments with risk of genotoxicity after the last dose of study treatment.

   * Female participants of childbearing potential should be willing to use 2 methods of birth control or be surgically sterile, or abstain from heterosexual activity for the course of the study through 120 days after the last dose of study medication. Medically accepted methods of birth control include a diaphragm, cervical cap, latex condoms, surgical sterility, intrauterine devices (IUDs), hormonal implants, injectable contraceptives, or birth control pills. Participants of childbearing potential are those who have not been surgically sterilized or have not been free from menses for \> 1 year.
   * Ability to tolerate radiation therapy (e.g., lie flat and hold position)
   * Demonstrate adequate hematologic, renal, hepatic, thyroid, and bone marrow function

Inclusion Criteria:

* Men and women age ≥ 18 years old (unless otherwise specified)
* Willing and able to provide written informed consent/assent
* ECOG Performance Status 0 - 1
* Patients with:

  * Newly diagnosed breast cancer with tumor size \< 5 cm who are not eligible for I-SPY2 (to prevent recruitment competition), or not recommended to undergo standard of care neoadjuvant chemotherapy with at least one of the following features:

    * Triple negative breast cancer (TNBC) defined using the ASCO CAP guidelines with the following modification supported by a recent publication as ER ≤ 10%, PR ≤ 10%, HER2- determined by immunohistochemistry and/or fluorescence in situ hybridization analyses and with tumor size ≤ 2.5 cm;
    * HR+ HER2- breast cancer regardless of nodal status and age of diagnosis ≥ 50
    * HR+ HER2- breast cancer and age of diagnosis \<50 with tumor size ≤ 2.5 cm and clinically node (+)
    * HR+ or HR- and HER2+ breast cancer with tumor size ≤ 2.5 cm
    * Ductal carcinoma in situ (DCIS) with microinvasion

OR

* Locally recurrent breast cancer of any receptor subtype with no prior radiation, not recommended to receive neoadjuvant chemotherapy and expecting surgical excision as part of treatment.

  • A female participant is eligible to participate if she is not pregnant (see Appendix 2), not breastfeeding, and at least one of the following conditions applies:
  1. Not a woman of childbearing potential (WOCBP) as defined in Appendix 2. OR
  2. A WOCBP who agrees to follow the contraceptive guidance in Appendix 2 during the treatment period and for at least 120 days for study treatments with risk of genotoxicity after the last dose of study treatment.

     • Female participants of childbearing potential should be willing to use 2 methods of birth control or be surgically sterile, or abstain from heterosexual activity for the course of the study through 120 days after the last dose of study medication. Medically accepted methods of birth control include a diaphragm, cervical cap, latex condoms, surgical sterility, intrauterine devices (IUDs), hormonal implants, injectable contraceptives, or birth control pills. Participants of childbearing potential are those who have not been surgically sterilized or have not been free from menses for \> 1 year.
     * Ability to tolerate radiation therapy (e.g., lie flat and hold position)
     * Demonstrate adequate hematologic, renal, hepatic, thyroid, and bone marrow function

     Exclusion criteria:

     • A WOCBP who has a positive urine pregnancy test within 72 hours prior to allocation. If the urine test is positive or cannot be confirmed as negative, a serum pregnancy test will be required.

     • A history of prior radiotherapy to the ipsilateral breast/chest wall that precludes delivery of hypofractionated radiotherapy.

     • 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).

     • Has received prior systemic anti-cancer therapy including investigational agents within 4 weeks

     • Has not adequately recovered from major surgery or has ongoing surgical complications

     • Has a known additional malignancy that is progressing or requires active treatment. Exceptions include basal cell carcinoma of the skin, squamous cell carcinoma of the skin, or in situ cervical cancer that has undergone potentially curative therapy.

     • Has active autoimmune disease that has required systemic treatment in the past 2 years except replacement therapy (eg., thyroxine, insulin, or physiologic corticosteroid)

     • Participants with vitiligo or resolved childhood asthma/atopy would be an exception to this rule. Participants that require intermittent use of bronchodilators or local steroid injections would not be excluded from the study. Participants with hypothyroidism stable on hormone replacement or Sjogren's syndrome will not be excluded from the study. Steroid prep due to dye allergies prior to staging scans or use in anti-emetic prophylaxis is allowed.

     • Has a history of (non-infectious) pneumonitis/interstitial lung disease that required steroids or has current pneumonitis/interstitial lung disease.

     • Has an active infection requiring systemic therapy.

     • Has a history or current evidence of any condition, therapy, or laboratory abnormality that might confound the results of the trial, interfere with the participant's participation for the full duration of the trial, or is not in the best interest of the participant to participate, in the opinion of the treating investigator.

     • Has known psychiatric or substance abuse disorders that would interfere with cooperation with the requirements of the trial.
     * Is pregnant or breastfeeding or expecting to conceive or father children within the projected duration of the trial, starting with the pre-screening or screening visit through 120 days after the last dose of trial treatment.
     * Has a known history of human immunodeficiency virus (HIV) (HIV 1/2 antibodies).
     * 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 received a live vaccine or live-attenuated vaccine within 30 days before the first dose of study intervention. Administration of killed vaccines is allowed.

     Note: please refer to Section 5.7 for information on COVID-19 vaccines • Has severe hypersensitivity (≥Grade 3) to pembrolizumab and/or any of its excipients.

     • Has had an allogenic tissue/solid organ transplant.

Where this trial is running

Philadelphia, Pennsylvania

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Breast CancerImmune checkpoint blockade
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.