Pembrolizumab and Binimetinib in Treating Patients With Locally Advanced or Metastatic Triple Negative Breast Cancer

PRIMARY OBJECTIVES:

I. To determine the maximum tolerated dose (MTD) of binimetinib in combination with pembrolizumab. (Phase I) II. To evaluate the objective response rate (ORR) of binimetinib in combination with pembrolizumab in patients with unresectable locally advanced or metastatic triple negative breast cancer by Response Evaluation Criteria in Solid Tumors (RECIST). (Phase II)

SECONDARY OBJECTIVES:

I. To evaluate the safety and tolerability of binimetinib in combination with pembrolizumab.

II. To evaluate the ORR by immune-related RECIST criteria (irRECIST). III. To evaluate the progression free survival (PFS), duration of response (DoR), and disease control rate (DCR) by RECIST and irRECIST.

IV. To assess overall survival (OS).

CORRELATIVE RESEARCH OBJECTIVES:

I. To assess the correlation between ORR, PFS, or OS and baseline and/or change in tumor infiltrating lymphocytes (TILs).

II. To assess the correlation between ORR, PFS, or OS and baseline and/or change in immune related gene signature and PDJ amplification.

III. To assess the change in immunoregulatory cells (IRC). IV. To assess the change in the cytokine profile. V. To assess the change in circulating tumor cells (CTC).

OUTLINE: This is phase I, dose-escalation study of binimetinib followed by a phase II study.

Patients receive binimetinib orally (PO) twice daily (BID) on days 1-14 of cycle 1 and on days 1-21 of cycle 2 and subsequent cycles. Beginning cycle 2, patients also receive pembrolizumab intravenously (IV) over 30 minutes on day 1. Cycle 1 equals 14 days. Cycles 2 and beyond repeat every 21 days in the absence of disease progression or unacceptable toxicity.

After completion of study treatment, patients are followed up at 30 days and then every 3 months until progressive disease, then every 6 months for up to 3 years.