Syndax Pharmaceuticals, Inc. is a United States-based clinical-stage biopharmaceutical company. The Company is focused on the development of entinostat as a combination therapy in multiple cancer indications with a focus on tumors that are sensitive to immunotherapy, including lung cancer, melanoma, ovarian cancer and triple-negative breast cancer (TNBC). The Company is also developing Entinostat as a combination therapeutic in a Phase III clinical trial, which is being conducted with ECOG-ACRIN for advanced hormone receptor positive (HR+) breast cancer. The Company's Entinostat is an oral, small molecule histone deacetylase (HDAC) inhibitor that has direct effects on both cancer cells and immune regulatory cells, and also enhances the body’s immune response to tumors. The Company's product pipeline for immune-oncology includes ENCORE 601, ENCORE 602, ENCORE 603, J1353, NCI-7870 and NCI-9844. Its pipeline for advanced HR+ breast cancer includes E2112.