A First-In-Human Phase I/IIa Study to Evaluate DA 3501 in Patients With Advanced Gastric or Gastro-esophageal Junction Adenocarcinoma and Pancreatic Ductal Adenocarcinoma

Inclusion Criteria: 1. Patients aged ≥ 19 years 2. Histologically or cytologically documented advanced CLDN18.2+ GC/GEJ adenocarcinoma or advanced CLDN18.2+ PDAC 3. Measurable disease as defined by Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST v1.1) 4. Life expectancy ≥12 weeks as judged by the Investigator Exclusion Criteria: 1. Cardiac abnormalities 2. Gastrointestinal abnormalities 3. Active and clinically significant bacterial, fungal, or viral infection, including known hepatitis B virus (HBV), known hepatitis C virus (HCV), known human immunodeficiency virus (HIV). 4. Active systemic infection requiring IV antibiotics therapy.