MEDI4736 and Tremelimumab in Treating Patients With Metastatic HER2 Negative Breast Cancer

PRIMARY OBJECTIVES: I. To evaluate clinical benefit rate in patients with metastatic HER2 negative breast cancer treated with MEDI4736 in combination with tremelimumab. SECONDARY OBJECTIVES: I. To evaluate progression free survival (PFS) and overall survival (OS) in patients with metastatic HER2 negative breast cancer treated with MEDI4736 in combination with tremelimumab. II. To evaluate safety and tolerability. TERTIARY OBJECTIVES: I. To evaluate if tissue-based immunohistochemical expression of programmed death-ligand (PD-L)1; tumor infiltrating lymphocytes (TILs); peripheral T cell subpopulations; changes in tissue and peripheral T cell receptor genotype; human leukocyte antigen (HLA) genotype; and immune-related candidate gene signatures predict response to MEDI4736 in combination with tremelimumab. II. To demonstrate the pharmacodynamic effects of MEDI4736 and tremelimumab on tissue and serum based biomarkers including PD-L1, TILs, T cell subpopulations, and T cell receptor genotype. OUTLINE: Patients receive MEDI4736 intravenously (IV) over 1 hour and tremelimumab IV over 1 hour on day 1. Treatment repeats every 28 days for 4 courses in the absence of disease progression or unacceptable toxicity. Four weeks after the last combination dose, patients continue to receive MEDI4736 every 2 weeks for up to 18 additional doses in the absence of disease progression or unacceptable toxicity. Patients who achieve clinical benefit (complete response \[CR\], partial response \[PR\], or stable disease \[SD\]) until the end of the 52 week period will then enter follow-up. During follow-up patients who develop PD may be re-treated with MEDI4736 at the dose previously administered IV for an additional 52 weeks using the same guidelines as with the initial 52 week period if they meet treatment in the setting of PD criteria. Only one 52 week retreatment period will be allowed. After completion of study treatment, patients are followed up at 3, 6, 9, and 12 months, and then every 6 months for 3 years.