Summary: The purpose of this study is to investigate the efficacy and safety of BGB-43395 in combination with letrozole compared with investigator's choice of cyclin-dependent kinase 4/6 inhibitor (CDK4/6i) in combination with letrozole in patients with advanced or metastatic hormone receptor positive (HR+)/human epidermal growth factor receptor 2 negative (HER2-) breast cancer (BC) who have not received p...

Background: NF1 is a genetic disease that causes tumors called atypical neurofibromas. These tumors, which arise from nerves, can cause serious medical problems. The only treatment is surgery. Researchers want to see if a drug called abemaciclib can help.

Summary: This phase I trial tests the safety, side effects, and best dose of ZEN003694 when given together with abemaciclib in treating patients with NUT carcinoma, breast cancer or other solid tumors that have spread from where it first started (primary site) to other places in the body (metastatic) or cannot be removed by surgery (unresectable). ZEN003694 is an inhibitor of a family of proteins called th...