Pembrolizumab vs. Observation in People With Triple-negative Breast Cancer Who Had a Pathologic Complete Response After Chemotherapy Plus Pembrolizumab

This phase III trial compares the effect of continuation of treatment with pembrolizumab (usual approach) to observation only at preventing cancer from coming back in patients with early-stage triple-negative breast cancer (TNBC) who achieved a pathologic complete response after preoperative chemotherapy in combination with pembrolizumab. The usual approach for patients with early-stage TNBC who receive preoperative chemotherapy plus pembrolizumab is to continue to receive pembrolizumab for up to 27 weeks after surgery. Immunotherapy with monoclonal antibodies, such as pembrolizumab, may help the body's immune system attack the cancer, and may interfere with the ability of tumor cells to grow and spread. This trial may help researchers determine if observation is as good as receiving pembrolizumab for 27 weeks after surgery in triple-negative breast cancer patients who achieved a pathologic complete response after preoperative treatment with chemotherapy and pembrolizumab.

NCT Number	NCT05812807
Lead Sponsor	Alliance for Clinical Trials in Oncology Collaborators: National Cancer Institute (NCI)
Conditions	Anatomic Stage II Breast Cancer AJCC v8, Early Stage Triple-Negative Breast Carcinoma, Anatomic Stage IIIA Breast Cancer AJCC v8, Anatomic Stage IIIB Breast Cancer AJCC v8
Enrollment	1,295 participants
Start Date	2023-06-14
Primary Completion	2033-05-31 (estimated)
Study Completion	2033-05-31 (estimated)
Updated on ClinicalTrials.gov	2026-08-05