Testing MT-304, an mRNA lipid-nanoparticle anti-HER2 CAR therapy, in adults with advanced HER2-expressing solid tumors.

A Phase 1, Open-Label, First-in-Human, Dose Escalation Study to Investigate the Safety, Pharmacokinetics, Pharmacodynamics and Preliminary Efficacy of MT-304 in Adults With Advanced HER2-Expressing Solid Tumors

Phase 1 Interventional Myeloid Therapeutics · NCT07334119

This will test MT-304, given alone or with nivolumab, in adults with advanced HER2-expressing solid tumors to find a safe dose and look for early signs of benefit.

Quick facts

PhasePhase 1
Study typeInterventional
Enrollment60 (estimated)
Ages18 Years and up
SexAll
SponsorMyeloid Therapeutics Industry-sponsored
Drugs / interventionsnivolumab
Locations6 sites (Randwick, New South Wales and 5 other locations)
Trial IDNCT07334119 on ClinicalTrials.gov

What this trial studies

This open-label, multicenter Phase 1 study administers MT-304 — an mRNA-encoded anti-HER2 chimeric antigen receptor delivered in lipid nanoparticles — as monotherapy (every 14 days) or combined with nivolumab (MT-304 every 14 days; nivolumab every 28 days). A Bayesian Optimal Interval (BOIN) dose-escalation design overseen by a Safety Review Committee will define the recommended Phase 2 dose. The trial collects safety, tolerability, pharmacokinetics, pharmacodynamics, and preliminary anti-tumor activity by RECIST 1.1, with regular labs and clinic assessments and up to two years of follow-up. Dosing adjustments are allowed based on clinical benefit and observed toxicities.

Who should consider this trial

Good fit: Adults aged 18 or older with measurable, advanced or metastatic epithelial cancers expressing HER2, ECOG performance status 0–1, and adequate organ function are the intended participants.

Not a fit: Patients with active CNS metastases or carcinomatous meningitis, uncontrolled pleural/pericardial effusion or ascites, recent significant autoimmune disease requiring systemic therapy, significant cardiac or pulmonary history, or acute illness are unlikely to be eligible and may not benefit.

Why it matters

Potential benefit: If successful, MT-304 could provide a new targeted immunotherapy option that produces durable tumor control for some patients with HER2-expressing solid tumors.

How similar studies have performed: mRNA LNP delivery of CAR constructs for solid tumors is a novel approach with limited clinical data to date, although other HER2-targeted therapies and checkpoint inhibitor combinations have shown benefit in different contexts.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Aged 18 years or above
* Histologically confirmed diagnosis of metastatic or advanced epithelial cancer expressing HER2 (Note: Participants with other tumor types expressing HER2 may be considered pending discussion with the Medical Monitor).
* Measurable lesion per RECIST 1.1 criteria.
* Eastern Cooperative Oncology Group (ECOG) performance status Grade of 0 or 1.
* Adequate Organ function

Exclusion Criteria:

* Known active CNS metastasis and/or carcinomatous meningitis.
* Any acute illness including fever.
* History of symptomatic congestive heart failure
* History of (noninfectious) pneumonitis/interstitial lung disease that required steroids or has current pneumonitis/interstitial lung disease.
* Uncontrolled pleural effusion, pericardial effusion, or ascites
* Active autoimmune disease not related to prior therapy for primary malignancy that has required systemic therapy in the last 1 year.

Where this trial is running

Randwick, New South Wales and 5 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 HER2-Expressing Solid TumorsAnti-HER2 chimeric antigen receptorChimeric Antigen ReceptormRNALipid nanoparticleUrothelial carcinomaEndometrial carcinomaOvarian epithelial carcinoma
Last reviewed 2026-06-13 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.