CCNE1 Amplified Advanced Solid Tumors

The goal of this open-label dose escalation and expansion study is to evaluate the safety and tolerability of NKT5097 in adults with advanced/metastatic tumors (emphasis on breast cancer and solid tumors with CCNE1 amplification). Main questions to answer include: * What is the recommended dose for expansion and/or Phase 2, for both monotherapy and in combination with ET * What medical issues/symptoms do participants experience when taking NKT5097 as monotherapy as well as in combination with ET