The purpose of this study is to see how effective the combination of the two chemotherapy drugs (carboplatin and nab-paclitaxel) are when added to a third drug, pembrolizumab.

Pembrolizumab is an investigational (experimental) drug that works by reinvigorating the immune system, allowing it to target and destroy cancer cells. Pembrolizumab is experimental because it is not approved by the Food and Drug Administration (FDA) for this type of breast cancer treatment.

Primary Objective - Determine overall response rate (ORR) in patients treated with CNP

Secondary Objective(s)

• Determine progression-free survival (PFS), and disease control rate (DCR) in patients treated with CNP.
• Determine duration of response in patients treated with CNP.
• Determine safety/tolerability of CNP.

Correlative Endpoints

- Identify pathologic and genomic correlates of response to CNP.

Study design including dose escalation / cohorts This is prospective pilot clinical trial of CNP in up to 30 patients with mTNBC

Inclusion Criteria:

• Subjects must have histologically or cytologically confirmed metastatic triple negative breast cancer

• Subjects must have received no more than 2 prior therapies for this disease

• ECOG Performance Status 0-1

• Subjects must have normal organ and marrow function as defined below:

  • Hemoglobin ≥ 10.0 g/dl
  • Absolute neutrophil count ≥ 1,000/μL
  • Platelet count ≥ 100,000/μL
  • Total bilirubin within normal institutional limits
  • AST (SGOT) ≤ 2.5 X institutional upper limit of normal
  • ALT (SGPT) ≤ 2.5 X institutional upper limit of normal
  • Serum creatinine ≤ 1.5 normal institutional limits

• Life expectancy of 12 weeks or more

• Subjects must have the ability to understand and the willingness to sign a written informed consent document

• Subjects must have measurable disease per RECIST v1.1

• Subjects must be willing to undergo a preliminary biopsy of a metastatic focus for research purposes. A second post-treatment biopsy will be offered but will not be mandated

Exclusion Criteria:

• Prior treatment toxicities have not resolved to ≤ Grade 1 according to NCI CTCAE Version 4.0 (except for alopecia and neuropathy)
• Subjects receiving any other investigational agents
• Subjects with radiographically stable treated brain metastases are eligible but must not have been on steroid therapy for at least 4 weeks
• History of allergic reactions attributed to compounds of similar chemical or biologic composition to nab-paclitaxel, carboplatin, pembrolizumab, or other agents used in this study
• Subjects with uncontrolled intercurrent illness including, but not limited to ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements
• Pregnant or breastfeeding women are excluded from this study
• Patients with conditions requiring immunosuppressive medications or chronic infections (including HIV infection, hepatitis B and C)
• Patients with chronic autoimmune disease
• Patients with prior therapy with antibodies that modulate T-cell function (e.g., anti-PD-1, anti-PD-L1)
• Patients with evidence of active, non-infectious pneumonia
• Patients active infection requiring intravenous systemic therapy
• Patients with known psychiatric or substance abuse disorders that would interfere with cooperation with requirements of the trial
• Patients who have received a live vaccine within 30 days prior to the first dose of pembrolizumab
• Patients with a known additional malignancy that is progressing or requires active treatment (within the last 5 years). Exceptions: basal cell carcinoma of the skin, squamous cell carcinoma of the skin or in situ cervical cancer that has undergone potentially curative therapy
• Patients who have received monoclonal anti-cancer antibody within 4 weeks of first dose of study drugs
• Patients who have received chemotherapy, small molecule targeted therapy or radiation within the 2 weeks of first dose of study drugs
• Patients who have participated in MK-3475 Merck studies
• Patients with carcinomatous meningitis

Up to five years after cycle six of treatment