Carboplatin and Paclitaxel With or Without Atezolizumab Before Surgery in Treating Patients With Newly Diagnosed, Stage II-III Triple-Negative Breast Cancer

This phase II trial studies how well carboplatin and paclitaxel with or without atezolizumab before surgery works in treating patients with newly diagnosed, stage II-III triple negative breast cancer. Immunotherapy with monoclonal antibodies, such as atezolizumab, may help the body's immune system attack the cancer, and may interfere with the ability of tumor cells to grow and spread. Drugs used in chemotherapy, such as carboplatin and paclitaxel, work in different ways to stop the growth of tumor cells, either by killing the cells, by stopping them from dividing, or by stopping them from spreading. Giving carboplatin and paclitaxel with or without atezolizumab before surgery may make the tumor smaller and reduce the amount of normal tissue that needs to be removed.

PRIMARY OBJECTIVES: I. To test the hypothesis that the combination of chemotherapy and atezolizumab will increase tumor infiltrating lymphocyte (TIL) percentage compared to chemotherapy alone in patients with newly diagnosed triple negative breast cancer (TNBC) being treated with neoadjuvant chemotherapy. II. To test the hypothesis that the combination of chemotherapy and atezolizumab will increase the pathologic complete response (pCR) rate compared to chemotherapy alone in patients with newly diagnosed TNBC being treated with neoadjuvant chemotherapy. SECONDARY OBJECTIVE: I. To evaluate the safety of the treatment combination of atezolizumab + carboplatin + paclitaxel. EXPLORATORY OBJECTIVES: I. To evaluate potential biomarkers of response to chemotherapy in combination with atezolizumab in patients with newly diagnosed TNBC. II. To evaluate the impact of chemotherapy in combination with atezolizumab on the immune response in patients with newly diagnosed TNBC. III. To evaluate the impact of chemotherapy in combination with atezolizumab on neoantigen-specific T cell responses in patients with newly diagnosed TNBC. IV. To evaluate the impact of chemotherapy in combination with atezolizumab on long-term clinical endpoints such as overall survival (OS) and disease-free survival (DFS) in patients with newly diagnosed TNBC. OUTLINE: Patients are randomized into 1 of 2 arms. ARM A: Patients receive carboplatin intravenously (IV) over 30 minutes once every 3 weeks (Q3W) and paclitaxel IV over 1 hour once weekly (QW). Treatment repeats every 3 weeks for up to 4 cycles in the absence of disease progression or unacceptable toxicity. ARM B: Patients receive atezolizumab IV over 30-60 minutes and carboplatin IV over 30 minutes Q3W, and paclitaxel IV over 1 hour QW. Treatment repeats every 3 weeks for up to 4 cycles in the absence of disease progression or unacceptable toxicity. In both arms, within 3-6 weeks, patients undergo mastectomy or lumpectomy. Patients also undergo the collection of blood samples throughout the trial. After completion of study treatment, patients are followed up at 6 months and 1 year.