A Study of DB-1324 in Advanced/Metastatic Gastrointestinal Tumors

This is a multicenter, open-label, multiple-dose, FIH Phase 1/2 study to explore the safety, tolerability, and efficacy of DB-1324 in participants with malignant GI tumors. The Phase 1, which includes Dose Escalation, Backfill, and Dose Expansion to identify the MTD and determine the RDEs and RP2D. Phase 2 will confirm the safety, tolerability, and explore efficacy in selected malignant GI tumors. For both Phase 1 and Phase 2, participants will receive study treatment until 1) disease progression, 2) loss of clinical benefit in the opinion of the investigator, 3) unacceptable toxicity, 4) withdrawal from study treatment by participant, 5) lost to follow up, or 6) another criterion for discontinuation is met, whichever occurs first.