This study is an Open-Label, Phase 1/2a, First-in-Human, Dose-Escalation, Dose-Expansion, and Proof-of-Concept Study to Investigate Safety, Tolerability, Pharmacokinetics, Pharmacodynamics, and Efficacy of DA-4505 as a Single Agent and in Combination With Pembrolizumab in Adult Patients With Locally Advanced or Metastatic Solid Tumors.

Inclusion Criteria:

1. Aged 18 and older.
2. Capable of giving signed informed consent.
3. Diagnosed with particular disease characteristics.
4. Expected survival ≥ 3 months.
5. Eastern Cooperative Oncology Group (ECOG) performance status ≤ 1.
6. A female patient is eligible to participate if she is not pregnant or breastfeeding.
7. A male patient is eligible to participate if he agrees to remain abstinent or use a male condom when having sexual intercourse with a WOCBP, or if he has had a bilateral vasectomy.
8. Have measurable disease by revised RECIST v1.1 criteria.

Exclusion Criteria:

1. Inability to take oral medications or gastrointestinal abnormalities potentially impacting absorption.
2. Current enrollment or past participation in another clinical trial.
3. Unresolved adverse reactions (except alopecia) from previous cancer-directed therapy.
4. Use of cancer-directed therapies, including chimeric antigen receptor T cell therapy.
5. Autologous transplantation within 60 days.
6. Prior allogeneic transplantation.
7. Major surgery within 30 days, or unresolved complications after a major or minor surgery.
8. History of or currently active cardiovascular disease.
9. Clinically significant respiratory, hepatic, renal, gastrointestinal, endocrinological, hematological, or neurological disorders.
10. History of other malignancy.