Syndax Pharmaceuticals, Inc. announced a new clinical collaboration with Genentech. As part of the collaboration, the two companies will evaluate the combination of Syndax's entinostat, an oral, small molecule, class I HDAC inhibitor, and Genentech's programmed cell death ligand 1 (PD-L1) blocking antibody, atezolizumab (TECENTRIQ), in patients with second-line hormone receptor positive, human epidermal growth factor receptor 2 negative (HR+, HER2-) metastatic breast cancer. The planned Phase Ib/II, open-label, multicenter, randomized trial will enroll patients with metastatic HR+, HER2- breast cancer who have experienced disease progression during or following first-line therapy. Genentech will be responsible for conducting the trial. The trial will be conducted as part of MORPHEUS, Roche's novel cancer immunotherapy development platform. MORPHEUS is a Phase Ib/II adaptive platform to develop combinations of cancer immunotherapies more rapidly and efficiently.