Randomized Phase 2 Study of Atezolizumab and Entinostat in Patients With aTN Breast Cancer With Phase 1b Lead In

SNDX-275-0602 is a Phase 1b/2 study evaluating the combination of entinostat plus atezolizumab in participants with aTNBC. The study has 2 phases: an open-label Dose Determination Phase (Phase 1b) followed by an Expansion Phase (Phase 2). The Expansion Phase will evaluate the efficacy and safety of entinostat when administered at the RP2D with atezolizumab in participants with aTNBC in a randomized, double-blind, placebo-controlled setting. Safety will be assessed during the study by documentation of AEs, clinical laboratory tests, physical examinations, vital sign measurements, electrocardiograms (ECGs), and Eastern Cooperative Oncology Group (ECOG) performance status. Adverse events of special interest (AESI) will be collected and reviewed in a manner consistent with serious adverse event reporting procedures.