E303 safety in people 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

Phase 1 Interventional Samsung Bioepis Co., Ltd. · NCT07524348

This Phase I trial will test whether the drug E303 is safe and tolerable in people with advanced solid tumors who have not responded to or cannot receive standard treatments.

Quick facts

PhasePhase 1
Study typeInterventional
Enrollment149 (estimated)
Ages18 Years and up
SexAll
SponsorSamsung Bioepis Co., Ltd. Industry-sponsored
Locations3 sites (Scottsdale, Arizona and 2 other locations)
Trial IDNCT07524348 on ClinicalTrials.gov

What this trial studies

This Phase I, multicenter, open-label trial gives E303 (also referred to as SBE303), a nectin-4–targeting antibody-drug conjugate, to adults with unresectable or metastatic solid tumors that progressed after or are not eligible for standard therapy. The study uses a dose-escalation design to determine safety, tolerability, and recommended dose while monitoring for dose-limiting toxicities and adverse events. Secondary assessments typically include pharmacokinetics and preliminary anti-tumor activity using standard imaging and response criteria. Enrollment focuses on patients whose disease is refractory to available treatments and who meet protocol eligibility and safety requirements.

Who should consider this trial

Good fit: Adults with histologically confirmed unresectable or metastatic solid tumors that have recurred or progressed during or after standard therapy, are intolerant of standard therapy, have refused standard therapy, or have no available standard options are candidates for this trial.

Not a fit: Patients with active central nervous system metastases, leptomeningeal disease, recent thromboembolic or significant bleeding events, significant cardiovascular disease, or active autoimmune disease are excluded and unlikely to benefit from participation.

Why it matters

Potential benefit: If successful, E303 could provide a new targeted treatment option that helps shrink tumors or control disease in some patients with advanced nectin-4–expressing solid tumors.

How similar studies have performed: Other nectin-4–targeting antibody-drug conjugates (for example enfortumab vedotin in urothelial cancer) have shown clinical benefit, so the general approach has precedent though E303 itself is being tested for the first time in this setting.

Eligibility criteria

Show full inclusion / exclusion criteria
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

Where this trial is running

Scottsdale, Arizona and 2 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Advanced Solid Tumors
Last reviewed 2026-06-09 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.