Home › Trials › NCT05150691

Evaluating DB-1303/BNT323 for HER2-positive advanced solid tumors

A Phase 1/2a, Multicenter, Open-Label, First in Human Study to Assess the Safety, Tolerability, Pharmacokinetics, and Preliminary Antitumor Activity of DB-1303/BNT323 in Patients With Advanced/Metastatic Solid Tumors

Phase1; Phase2 Interventional DualityBio Inc. · NCT05150691

This study is testing a new treatment called DB-1303/BNT323 to see if it is safe and effective for people with advanced solid tumors that have high levels of HER2.

Quick facts

PhasePhase1; Phase2
Study typeInterventional
Enrollment796 (estimated)
Ages18 Years and up
SexAll
SponsorDualityBio Inc. Industry-sponsored
Locations102 sites (Cerritos, California and 101 other locations)
Trial IDNCT05150691 on ClinicalTrials.gov

What this trial studies

This Phase 1/2a trial aims to assess the safety and tolerability of DB-1303/BNT323 in patients with advanced solid tumors that express HER2. The study is divided into two parts: the first part uses a dose-escalation approach to determine the maximum tolerated dose (MTD) and recommended phase 2 dose (RP2D), while the second part focuses on expanding the cohort to confirm safety and explore efficacy at the identified dose. Participants will be enrolled based on specific criteria, including having measurable lesions and being refractory to standard treatments.

Who should consider this trial

Good fit: Ideal candidates include individuals with HER2-positive advanced, unresectable, recurrent, or metastatic solid tumors who have not responded to standard therapies.

Not a fit: Patients with HER2-negative tumors or those who have not progressed after standard treatments may not benefit from this study.

Why it matters

Potential benefit: If successful, this treatment could provide a new therapeutic option for patients with HER2-positive advanced solid tumors that have limited treatment alternatives.

How similar studies have performed: Other studies targeting HER2-positive tumors have shown promise, indicating that this approach may be beneficial, although this specific combination is novel.

Eligibility criteria

Show full inclusion / exclusion criteria 
Inclusion Criteria:

* Has a pathologically documented HER2-positive or HER2-expressing (except for cohort 2h where the requirement is HER2-null), advanced/unresectable, recurrent, or metastatic malignant solid tumor that is refractory to or intolerable with standard treatment, or for which no standard treatment is available.
* At least 1 measurable lesion (per RECIST 1.1)
* Provide signed informed consent
* ECOG performance status (PS) of 0-1.
* LVEF ≥ 50% by ECHO or MUGA
* Adequate organ functions
* Provide pre-existing diagnosis of HER2 status or resected tumor samples or undergo fresh tumor biopsy for HER2 testing.
* Life expectancy of ≥ 3 months.

Additional Inclusion Criteria for Part 2 Expansion Group 9:

1\. Has pathologically documented advanced/unresectable, recurrent, or metastatic EC (including UCS and USPC) and has progressed on or after at least 1 line of systemic treatment including platinum-based therapy and exposure to ICI but no more than prior 3 lines of therapy for advanced/unresectable, or metastatic disease. Note: endocrine therapy will not qualify as a systemic therapy line.

Exclusion Criteria:

* History of symptomatic CHF (New York Heart Association \[NYHA\] classes II-IV) or serious cardiac arrhythmia requiring treatment.
* History of myocardial infarction or unstable angina within 6 months before Day 1.
* Average QTcF \> 450 ms in males and \> 470 ms in females
* History of clinically significant lung diseases
* Uncontrolled infection requiring IV antibiotics, antivirals, or antifungals.
* HIV infection with AIDS defining illness or active viral hepatitis.
* Clinically active brain metastases
* Unresolved toxicities from previous anticancer therapy, defined as toxicities not yet resolved to NCI-CTCAE version 5.0, Grade ≤ 1 or baseline.
* A known hypersensitivity to either the drug substances or inactive ingredients in the drug product.
* Part 2 (expansion) Only:Multiple primary malignancies within 3 years, except adequately resected non- melanoma skin cancer, curatively treated in-situ disease, other solid tumors curatively treated, or contralateral breast cancer.

Where this trial is running

Cerritos, California and 101 other locations

+52 more sites — see ClinicalTrials.gov for the full list.

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.
View on ClinicalTrials.gov → Find more trials like this →
Conditions HER2-positive Advanced Solid TumorHER2HER2-positiveHER2-positive Breast CancerHER2-positive Gastric CancerHER2-positive Endometrial CancerHER2-positive Biliary Tract CancerHER2 low
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.