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

May 18, 2026 updated by: Dong-A ST Co., Ltd.

A First-In-Human Phase I/IIa Study to Evaluate the Safety, Tolerability, Pharmacokinetics, Pharmacodynamics, and Efficacy of DA 3501 in Patients With Advanced Gastric or Gastro-esophageal Junction Adenocarcinoma and Pancreatic Ductal Adenocarcinoma

The goal of this clinical trial is to determine the MTD or OBED of DA-3501 given in Q3W to determine a wRP2D in patients with advanced CLDN18.2 expressing (CLDN18.2+) GC/GEJ and advanced CLDN18.2+ PDAC.

Participants will receive the assigned dose once every three weeks and, according to the study procedures, will undergo tumor assessments as well as safety assessments, PK evaluations, and ADA testing.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

51

Phase

  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • South Korea
    • Bundang
      • Seongnam, Bundang, South Korea, 13496
        • Recruiting
        • CHA University Bundang Medical Center
      • Seongnam, Bundang, South Korea, 13620
        • Recruiting
        • Seoul National University Bundang Hospital
    • Seoul
      • Seoul, Seoul, South Korea, 03722
        • Recruiting
        • Severance Hospital

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

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.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Non-Randomized
  • Interventional Model: Sequential Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Dose Level 2
Drug: DA-3501
Participant will receive DA-3501 at the assigned dose level administered intravenously once every three weeks.
Experimental: Dose Level 3
Drug: DA-3501
Participant will receive DA-3501 at the assigned dose level administered intravenously once every three weeks.
Experimental: Dose Level 4
Drug: DA-3501
Participant will receive DA-3501 at the assigned dose level administered intravenously once every three weeks.
Experimental: Dose Level 5
Drug: DA-3501
Participant will receive DA-3501 at the assigned dose level administered intravenously once every three weeks.
Experimental: Dose Level 6
Drug: DA-3501
Participant will receive DA-3501 at the assigned dose level administered intravenously once every three weeks.
Experimental: Dose Level 7
Drug: DA-3501
Participant will receive DA-3501 at the assigned dose level administered intravenously once every three weeks.
Experimental: Dose Level 8
Drug: DA-3501
Participant will receive DA-3501 at the assigned dose level administered intravenously once every three weeks.
Experimental: Dose Level 9
Drug: DA-3501
Participant will receive DA-3501 at the assigned dose level administered intravenously once every three weeks.
Experimental: Dose Level 1
Participants will receive DA-3501 at dose level 1 administered intravenously once every three weeks.
Drug: DA-3501
Participant will receive DA-3501 at the assigned dose level administered intravenously once every three weeks.
Experimental: Dose Level 10
Drug: DA-3501
Participant will receive DA-3501 at the assigned dose level administered intravenously once every three weeks.
Experimental: Dose Level 11
Drug: DA-3501
Participant will receive DA-3501 at the assigned dose level administered intravenously once every three weeks.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Maximum Tolerated Dose (MTD) based on Dose-Limiting Toxicities (DLTs) during Cycle 1
Time Frame: 21 days
21 days
Optimal Biological Effective Dose (OBED) Based on best Overall Response Rate (ORR)
Time Frame: 42 days
42 days

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Dong-A ST Co., Ltd.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

May 18, 2026

Primary Completion (Estimated)

February 1, 2028

Study Completion (Estimated)

February 1, 2029

Study Registration Dates

First Submitted

February 25, 2026

First Submitted That Met QC Criteria

March 16, 2026

First Posted (Actual)

March 18, 2026

Study Record Updates

Last Update Posted (Actual)

May 20, 2026

Last Update Submitted That Met QC Criteria

May 18, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • DA3501_AMST_I/IIa

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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