Phase I/Ii Trial Of Pembrolizumab In Combination With Binimetinib In Unresectable Locally Advanced Or Metastatic Triple Negative Breast Cancer.

TPS17Background: Emerging studies suggest that breast cancer, particularly triple negative breast cancer (TNBC), may be sensitive to immunotherapy. However, the response rate of single agent immune checkpoint blockade agent in TNBC is rather low. Previous genomic study in residual tumor after neoadjuvant chemotherapy showed inverse correlations between MEK activation signature and the amount of tumor infiltrating lymphocytes (TILs) in residual disease samples as well as poor outcome. Preclinical study also showed that the combination of MEK inhibitor and anti-PD-L1 antibody in mouse model can eradicate TNBC tumors. Methods: This is a single arm, Phase I/II trial of Pembrolizumab (P) in combination with Binimetinib (B) in patients with unresectable locally advanced or metastatic TNBC. This trial is currently opened for accrual at Mayo Clinic in Florida and Minnesota. Patients with TNBC defined as ER ≤ 10% and PR ≤ 10% who received ≤ 3 prior lines with measurable disease will be enrolled. The primary object...