Neoadjuvant, SBRT With Intratumoural Pembrolizumab Followed by Neoadjuvant Chemotherapy in Breast Cancer
This study will evaluate the immune-priming effects of stereotactic body radiation therapy (SBRT) regimen coupled with two injections of pembrolizumab in high-risk primary breast carcinoma prior to neoadjuvant chemotherapy. Preliminary results from the investigators' local TRIO Trial suggest that SBRT prior to neoadjuvant chemotherapy (NAC) may result in improved response rates due to the combined effect of radiation therapy (RT) and chemotherapy. The investigators aim to augment this effect with the addition of…
Breast Cancer, Breast Cancer Stage II, Breast Cancer Stage III, Breast Cancer Invasive, Breast Cancer Triple Negative
About this study
This study will evaluate the immune-priming effects of stereotactic body radiation therapy (SBRT) regimen coupled with two injections of pembrolizumab in high-risk primary breast carcinoma prior to neoadjuvant chemotherapy. Preliminary results from the investigators' local TRIO Trial suggest that SBRT prior to neoadjuvant chemotherapy (NAC) may result in improved response rates due to the combined effect of radiation therapy (RT) and chemotherapy. The investigators aim to augment this effect with the addition of pembrolizumab, a monoclonal antibody that binds to and blocks programmed cell death protein 1 (PD-1).
Interventions
Radiation: Radiation — Stereotactic body radiation therapy to the breast
Drug: Pembrolizumab (KEYTRUDA®) — Two injections
Primary outcomes
Pathological Complete Response (Measured at time of surgery, typically 6 months after enrollment in trial.)
Eligibility information
Inclusion Criteria:
1. Invasive ductal carcinoma of any subtype (including invasive mammary carcinoma with lobular features), excluding sarcomatous, signet or metaplastic subtypes.
2. Invasive mammary carcinoma of stages IIB - III (excluding inflammatory breast cancer). Stage IIA is eligible for triple negative and HER2+ breast cancers.
a. Clinical staging based on AJCC 8th edition.
3. Lesion palpable by treating physician.
4. Plan to be treated with neoadjuvant chemotherapy.
5. Able to tolerate core needle biopsies and pembrolizumab injection.
6. 18 years of age or older.
7. Able to provide informed consent.
Exclusion Criteria:
1. Any serious medical comorbidities or other contraindications to radiotherapy, chemotherapy, or surgery (e.g., uncontrolled diabetes, serious heart condition, etc).
2. Prior treatment for current breast cancer.
3. Previous radiation therapy to the same breast.
4. Inflammatory breast carcinoma.
5. Invasive mammary carcinoma with sarcomatous, signet cell or metaplastic subtypes.
6. Recurrent breast cancer.
7. Clinical or radiologic evidence or suspicion of distant metastatic disease (metastatic workup that requires additional imaging to follow-up on suspicious findings will exclude patients).
8. Any collagen vascular disease precluding radiotherapy at the discretion of the treating radiation oncologist (particularly lupus, scleroderma, dermatomyositis, psoriatic arthritis).
9. No prior stem cell transplantation.
10. Any poorly controlled autoimmune conditions.
11. Current use of corticosteroids or immunosuppressants.
12. Any other malignancy at any site (except non-melanomatous skin cancer) \<5 years prior to study enrollment. Synchronous bilateral breast cancers are acceptable.
13. Inability to tolerate core needle biopsies or pembrolizumab injection.
14. Pregnant or lactating.
15. Under 18 years of age.
16. Inability or unwillingness to provide informed consent.
17. Inability or unwillingness to complete study assessments/interventions and follow-up assessments.
Study locations
St. Joseph's Health Care London, London, Ontario N6A 4V2 Canada
St. Joseph's Health Care London, London, Ontario Canada
Before you participate: Varda Clinical is an independent discovery tool, not the study sponsor or a medical provider. Eligibility can only be determined by the official study team. Discuss potential risks and benefits with a qualified healthcare professional.
Source: ClinicalTrials.gov. Record last refreshed by Varda Clinical: 2026-11-15.