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
Able to provide written informed consent
Advanced unresectable or metastatic solid tumor (Part 1, 2 & 3 only)
Advanced unresectable or metastatic HR+/HER2- breast cancer (Part 4 & 5 only)
Refractory to or unable to tolerate existing therapies (Part 1, 2 & 4 only)
Advanced solid tumor that is a candidate for curative treatment
History of another malignancy except for the following: adequately treated local basal cell or squamous carcinoma of the skin, in situ cervical cancer, adequately treated papillary noninvasive bladder cancer, other adequately treated Stage I or Stage II cancers currently in complete remission
Not recovered from the effects of prior anticancer therapy
Clinically significant cardiovascular event, including myocardial infarction, arterial thromboembolism, or cerebrovascular thromboembolism, within 6 months