The main purpose of this study is to determine the anti-tumor activity of MEDI4736 in combination with tremelimumab in patients with metastatic HER2-negative breast cancer. Both MEDI4736 and tremelimumab are antibodies (proteins used by the immune system to fight infections and cancers). MEDI4736 attaches to a protein in tumors called PD-L1. It may prevent cancer growth by helping certain blood cells of the immune system get rid of the tumor. Tremelimumab stimulates (wakes up) the immune system to attack the tumor by inhibiting a protein molecule called CTLA-4 on immune cells. Combining the actions of these drugs may result in better treatment options for patients with 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.

Inclusion Criteria:

• Patients must have a histologically documented (either primary or metastatic site) diagnosis of breast cancer that is HER2 non-overexpressing by immunohistochemistry, namely 0 or 1; if they have an equivocal immunohistochemistry, 2, the tumor must be non-gene amplified by fluorescence in situ hybridization (FISH) performed upon the primary tumor or metastatic lesion (ratio < 2 and HER2 copy number < 4); estrogen receptor (ER) positivity is defined as 1% or greater

• Patients must have measurable disease by Response Evaluation Criteria in Solid Tumors (RECIST) criteria

• Patients who are ER negative must have progressed through at least one prior chemotherapy regimen in the metastatic setting or within 12 months of their last adjuvant systemic treatment; patients who are ER positive must have progressed through standard hormone therapy options and have received at least one line of chemotherapy in the metastatic setting

• Completion of prior chemotherapy systemic anticancer therapy at least 2 weeks prior to study entry

• Radiation therapy must be completed at least 2 weeks prior to study entry; radiated lesions may not serve as measurable disease unless they have been radiated over 12 months prior to enrollment

• Patients may have parenchymal brain metastases if stable (no evidence of progression) for at least 1 month after local therapy (radiation or surgery); leptomeningeal disease is excluded; must have completed any prescribed steroid taper

• Patients may have had a prior diagnosis of cancer if it has been > 5 years since their last treatment

• Patients must exhibit an Eastern Cooperative Oncology Group (ECOG) performance status of =< 2

• Absolute neutrophil count >= 1,000/mcL

• Platelets >= 50,000/mcl

• Total bilirubin =< 1.5 times the institutional upper limit of normal (ULN) (or =< 3 times ULN in case of liver metastasis)

• Aspartate aminotransferase (AST) (serum glutamic oxaloacetic transaminase [SGOT])/alanine aminotransferase (ALT) (serum glutamate pyruvate transaminase [SPGT]) =< 2.5 X institutional ULN (or =< 5 times ULN in case of liver metastasis)

• Creatinine =< 2 ng/ml

• Females of child-bearing potential (FOCBP) and males must agree to use 2 methods of adequate contraception prior to study entry, for the duration of study participation, and for number (#) days following completion of therapy; should a female patient become pregnant or suspect she is pregnant while participating in this study, she should inform her treating physician immediately

  • NOTE: A FOCBP is any woman (regardless of sexual orientation, having undergone a tubal ligation, or remaining celibate by choice) who meets the following criteria:
  • Has not undergone a hysterectomy or bilateral oophorectomy
  • Has had menses at any time in the preceding 12 consecutive months (and therefore has not been naturally postmenopausal for > 12 months)

• FOCBP must have a negative pregnancy test within 7 days prior to registration on study

• Willingness to provide a fresh biopsy prior to study enrollment and after 2 cycles of treatment

• Patients must have the ability to understand and the willingness to sign a written informed consent prior to registration on study

Exclusion Criteria:

• Patients who have had chemotherapy or radiotherapy within 2 weeks prior to entering the study or those who have not recovered from adverse events due to agents administered more than 4 weeks earlier are not eligible.

• Current or prior use of immunosuppressive therapy within 2 weeks of starting investigational therapy

• Patients who are taking any herbal (alternative) medicines are NOT eligible for participation; patients must be off any such medications by the time of registration for at least 2 weeks; NOTE: Vitamin supplements are acceptable

• Patients may not have received any other investigational agents within 4 weeks prior to registration

• Prior treatment with immune therapy (including but not limited to cluster of differentiation [CD]137, OX40, programmed death [PD]-1, PD-L1 or cytotoxic T-lymphocyte antigen 4 [CTLA4] inhibitors)

• Prior severe infusion reaction to a monoclonal antibody

• Patients with a history of or active autoimmune disease within the past 3 years with the following exceptions:

  • Vitiligo or alopecia
  • Hypothyroidism on stable doses of thyroid replacement therapy
  • Psoriasis not requiring systemic therapy within the past 3 years

• History of primary immunodeficiency disease or tuberculosis

• Major medical conditions that might affect study participation (uncontrolled pulmonary, renal, or hepatic dysfunction, uncontrolled infection) are not eligible; other significant comorbid condition which the investigator feels might compromise effective and safe participation in the study

• Patients who have an uncontrolled intercurrent illness including, but not limited to any of the following, are not eligible:

  • Uncontrolled pulmonary, renal, or hepatic dysfunction
  • Ongoing or active infection requiring systemic treatment
  • Known active or chronic viral hepatitis or human immunodeficiency virus (HIV)
  • Psychiatric illness/social situations that would limit compliance with study requirements
  • Any other illness or condition that the treating investigator feels would interfere with study compliance or would compromise the patient's safety or study endpoints

• Female patients who are pregnant or nursing are not eligible