DB-1324-101

This study, the first clinical trial, aims to determine the safety, tolerability, pharmacokinetics, pharmacodynamics, maximum tolerated dose, and antitumor activity of DB-1324.

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.