A Trial to Investigate the Safety of E303 in Participants With Advanced Refractory Solid Tumors

A Phase I, Open-Label, Multi-Center, First-in-Human Trial to Investigate E303, in Participants With Advanced Refractory Solid Tumors

This is a Phase I trial to evaluate the safety, tolerability and efficacy of nectin-4 targeting antibody-drug conjugate (SBE303) in participants with advanced solid tumors

Study Overview

• Status: Recruiting
• Conditions: Advanced Solid Tumors
• Intervention / Treatment: Drug: E303

• Study Type: Interventional
• Enrollment (Estimated): 149
• Phase: Phase 1

Contacts and Locations

• Study Contact: Name: Samsung Bioepis; Phone Number: +82-32-728-0114; Email: bioepisinfo@samsung.com

Study Locations

• Australia
  • Adelaide, Australia
    • Recruiting
    • Research Site
• Spain
  • Barcelona, Spain
    • Recruiting
    • Research Site
• United States
  • Arizona
    • Scottsdale, Arizona, United States, 85258
      • Recruiting
      • Research Site
  • Virginia
    • Fairfax, Virginia, United States, 22031
      • Recruiting
      • Research Site

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Histologically-confirmed, locally advanced (unresectable) or metastatic solid tumors with recurrence or progression during or after standard therapy, intolerance to standard therapy, refused to receive standard therapy, or for whom no standard therapy is available.

Exclusion Criteria:

• Have spinal cord compression or clinically active central nervous system metastases
• Have leptomeningeal disease
• Have thromboembolic or clinically significant bleeding events
• Have significant cardiovascular disease
• Have an active autoimmune disease

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Sequential Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: E303	Drug: E303; All participants will receive an intravenous (IV) infusion of E303

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of adverse events and serious adverse events		Until trial completion (estimated 3 years)
Incidence of dose limiting toxicity		For the first cycle of treatment, through pre-dose Cycle 2 Day 1
Confirmed objective response rate	Efficacy enpoint per Blinded Independent Central Review (BICR), according to Response Evaluation Criteria in Solid Tumors (RECIST) v1.1	32 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Tumor response	Efficacy endpoint per BICR, according to RECIST v1.1	32 weeks
Disease control rate	Efficacy endpoint per BICR, according to RECIST v1.1	32 weeks
Area under the plasma/serum concentration vs time curve of total E303		Until trial completion (estimated 3 years)
Maximum plasma/serum concentration of total E303		Until trial completion (estimated 3 years)
Time to reach maximum plasma/serum concentration of total E303		Until trial completion (estimated 3 years)
Plasma/serum concentration before the next dose of total E303		Until trial completion (estimated 3 years)
Terminal half life of total E303		Until trial completion (estimated 3 years)
Incidence and titer of anti-drug antibodies		Until trial completion (estimated 3 years)
Incidence of neutralizing antibodies		Until trial completion (estimated 3 years)

Collaborators and Investigators

• Sponsor: Samsung Bioepis Co., Ltd.

Study record dates

Study Major Dates

• Study Start (Actual): March 23, 2026
• Primary Completion (Estimated): July 1, 2030
• Study Completion (Estimated): July 1, 2030

Study Registration Dates

• First Submitted: March 26, 2026
• First Submitted That Met QC Criteria: April 6, 2026
• First Posted (Actual): April 13, 2026

Study Record Updates

• Last Update Posted (Actual): June 1, 2026
• Last Update Submitted That Met QC Criteria: May 28, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Other Study ID Numbers: E303-1001

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No