A Dose Finding Phase 1 of Sarilumab Plus Capecitabine in HER2/Neu-Negative Metastatic Breast Cancer and a Single-arm, Historically-controlled Phase 2 Study of Sarilumab Plus Capecitabine in Stage I-III Triple Negative Breast Cancer With High-Risk Residual Disease (EMPOWER)

The study will consist of two phases, I and II. Phase I will include patients with metastatic TNBC, HER2/neu-negative and hormone resistant breast cancer. A total of 4 doses of sarilumab will be given with the starting dose of 150 mg SQ at 3-weeks cycles given 3 days prior to each of the first 4 of 8 cycles of capecitabine (1000 mg/m2/BID; for 14 days every 21 days). If dose escalation is possible, sarilumab will be administered every 3 weeks at 200 mg SQ for 4 doses. Blood samples will be obtained prior during the course of treatment. Bone marrow samples are optional. Phase II is a single arm study in Stage I to III TNBC with less than a complete pCR after neoadjuvant therapy evaluating the combination of sarilumab with capecitabine (1000mg/m2/BID; for 14 days every 21 days) as compared to historical control patients treated with capecitabine alone. There are 8 cycles of capecitabine. The first 4 cycles will be combined with sarilumab. The Phase II sarilumab dose will be determined by the Phase I best tolerated dose. Blood samples will be obtained prior during the course of treatment. Bone marrow samples are optional. A pilot parallel biological baseline study of standard adjuvant capecitabine in stage I to III TNBC with less than a pCR will be performed. This Arm will be open in parallel with both Phases 1 and 2. Blood samples will be obtained prior during the course of treatment. Bone marrow samples are optional.