A012103: Pembrolizumab vs. Observation in People With Triple-negative Breast Cancer Who Had a Pathologic Complete Response After Chemotherapy Plus Pembrolizumab

The phase III trial compares the effect of pembrolizumab to observation for the treatment of patients with early-stage triple-negative breast cancer who achieved a pathologic complete response after preoperative chemotherapy in combination with pembrolizumab. 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 will result in the same risk of cancer coming back as pembrolizumab after surgery in triple-negative breast cancer patients who achieve pathologic complete response after preoperative chemotherapy with pembrolizumab.

Male and Female – 18 years and older

• Triple Negative Breast Cancer: Patients with a history of stage T1cN1-2 or T2-4N0-2 breast cancer according to the primary tumor-regional lymph node anatomic staging criteria of the American Joint Committee on Cancer (AJCC), 8th edition as determined by the investigator in radiologic assessment, clinical assessment or both
• Triple Negative Breast Cancer: Patients must have no residual invasive disease in the breast or lymph nodes after the completion of neoadjuvant therapy. Residual ductal carcinoma in situ (DCIS) is allowed. Isolated tumor cells are considered node-negative
• Triple Negative Breast Cancer: Estrogen (ER) and progesterone (PR) =< 10%; HER2-negative by American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP) guidelines (immunohistochemistry [IHC] and fluorescence in situ hybridization [FISH])
• If invasive disease was present in both breasts, participation in the study is permitted as long as the eligibility criteria are met for both tumors/breasts
• Patients must have received neoadjuvant chemotherapy in combination with pembrolizumab for a minimum of 6 cycles. All systemic chemotherapy and ICI therapy should have been completed preoperatively
• 18 years or older of age
• Use of investigational anti-cancer agents must be discontinued at time of registration

• No stage IV (metastatic) breast cancer
• No history of any prior (ipsi- or contralateral) invasive breast cancer. Prior DCIS is allowed
• No evidence of recurrent disease following preoperative therapy and surgery
• No known active liver disease, e.g. due to hepatitis B virus (HBV), hepatitis C virus (HCV), autoimmune hepatic disorders, or sclerosing cholangitis