Safety, Pharmacokinetics, Pharmacodynamics and Preliminary Efficacy of MT-304 in Adults With Advanced HER2-Expressing Solid Tumors

May 18, 2026 updated by: Myeloid Therapeutics

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

This clinical trial is designed to evaluate the safety, pharmacokinetics, pharmacodynamics, and preliminary efficacy of MT-304 in adults with advanced HER2-expressing solid tumors. The main questions it aims to answer are:

  • What is the safety profile of MT-304 when administered alone or with nivolumab?
  • What is the recommended Phase 2 dose (RP2D) of MT-304?

Participants will:

  • Receive MT-304 alone (every 14 days) or with nivolumab (every 28 days).
  • Attend regular clinic visits for assessments and monitoring.
  • Continue treatment until disease progression, unacceptable toxicity, or study discontinuation.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

This multicenter, open-label, Phase 1 trial is designed to assess the safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD), and preliminary efficacy of MT-304 in adults aged 18 and older with advanced HER2-expressing solid tumors.

The study consists of two treatment modules:

  • Module 1 (Monotherapy): Participants receive MT-304 every 14 days for 28-day cycles, with dosing adjustments based on clinical benefit and safety evaluations.
  • Module 2 (Combination Therapy): Participants receive MT-304 in combination with nivolumab, administered every 14 days and 28 days, respectively, also allowing for dosing adjustments.

The Bayesian Optimal Interval (BOIN) design will guide dose escalation, overseen by a Safety Review Committee to establish the recommended Phase 2 dose (RP2D).

Regular assessments, including vital signs and laboratory tests, will monitor safety and efficacy throughout the trial, with follow-up visits for up to 2 years post-treatment.

Study Type

Interventional

Enrollment (Estimated)

60

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 Contact Backup

Study Locations

  • Australia
    • New South Wales
      • Darlinghurst, New South Wales, Australia, 2010
        • Recruiting
        • The Kinghorn Cancer Centre
        • Contact:
          • Dr Rasha Cosman
          • Phone Number: +61393555655
        • Principal Investigator:
          • Dr Rasha Cosman
      • Randwick, New South Wales, Australia, 2031
      • Waratah, New South Wales, Australia, 2298
        • Recruiting
        • Calvary Mater Newcastle
        • Contact:
          • Kerrie Cornall
          • Phone Number: +61240143282
        • Principal Investigator:
          • Dr Jordan Cohen
    • Queensland
      • South Brisbane, Queensland, Australia, 4101
        • Recruiting
        • Icon Cancer Centre South Brisbane
        • Contact:
          • A/Prof Jermaine Coward
          • Phone Number: +61737374500
        • Principal Investigator:
          • A/Prof Jermaine Coward
    • South Australia
      • Adelaide, South Australia, Australia, 5000
        • Recruiting
        • Cancer Research SA Pty Ltd
        • Contact:
          • Dr Meena Okera
          • Phone Number: +61883592565
        • Principal Investigator:
          • Dr Meena Okera
    • Victoria
      • Melbourne, Victoria, Australia, 3144
        • Recruiting
        • Cabrini Health
        • Contact:
          • Dr. Prachi Bhave
          • Phone Number: +61395083437
        • Principal Investigator:
          • Dr. Prachi Bhave
    • Western Australia
      • Nedlands, Western Australia, Australia, 6009
        • Recruiting
        • Linear Clinical Research
        • Principal Investigator:
          • Dr Timothy Humphries
        • Contact:
          • Dr Timothy Humphries
          • Phone Number: +61863825100

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:

  • 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.

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: MT-304 Monotherapy
Participants receive MT-304 administered intravenously once every 14 days (Q14D) in escalating dose levels.
Drug: MT-304
Safety, tolerability, and pharmacokinetics will be evaluated.
Other Names:
  • mRNA-LNP
Experimental: MT-304 + Nivolumab Combination Therapy
Participants receive MT-304 administered intravenously once every 14 days (Q14D) in combination with nivolumab as "per local label" administered once every 28 days (Q28D).
Drug: MT-304 + Nivolumab
Combination therapy begins after monotherapy dose clearance by the Safety Review Committee.
Other Names:
  • mRNA-LNP

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Type, incidence and severity of Adverse Events
Time Frame: Up to 90 days from the last dose of Investigational Medicinal Product (IMP)
Safety and tolerability profile assessed by the Common Terminology Criteria for Adverse Events v5.
Up to 90 days from the last dose of Investigational Medicinal Product (IMP)
Number of Participants With Change From Baseline in Vital Signs (Composite Safety Outcome)
Time Frame: Up to 30 days from the last dose of IMP
Body temperature, body weight, pulse rate, and blood pressure (systolic and diastolic) assessed collectively; participants with clinically significant changes in any vital sign parameter will be summarized as a composite safety outcome.
Up to 30 days from the last dose of IMP
Number of Participants With Abnormal Clinical Laboratory Parameters (Composite Safety Outcome)
Time Frame: Up to 30 days from the last dose of IMP
Hematology, clinical chemistry, coagulation, virology testing, and urinalysis assessed collectively; participants with abnormalities in any laboratory parameter will be summarized as a composite safety outcome.
Up to 30 days from the last dose of IMP
Number of Participants With Change From Baseline in ECG Parameters (Composite Safety Outcome)
Time Frame: Screening through Day 28, with assessments performed on Screening, Day 1 (pre-dose), and Day 28.
PR interval, QRS duration, QT interval, corrected QT interval (QTc), and heart rate assessed collectively from 12-lead ECG recordings; participants with clinically significant changes in any ECG parameter will be summarized as a composite safety outcome.
Screening through Day 28, with assessments performed on Screening, Day 1 (pre-dose), and Day 28.
Maximum Tolerated Dose (MTD)
Time Frame: 28 days from the last dose of IMP
The MTD in Module 1 (monotherapy) will be determined based on dose-limiting toxicities (DLTs).
28 days from the last dose of IMP
Optimal Biological Dose (OBD)
Time Frame: 28 days from the last dose of IMP
The OBD in Module 2 (combination) will be identified based on dose-limiting toxicities (DLTs).
28 days from the last dose of IMP

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Pharmacokinetics (PK)
Time Frame: From Day 1, Day 2, Day 8, and Day 15 of Cycles 1 and 2, and Day 1 of Cycle 3 (each cycle is 28 days).
PK Parameter: Maximum plasma concentration (Cmax)
From Day 1, Day 2, Day 8, and Day 15 of Cycles 1 and 2, and Day 1 of Cycle 3 (each cycle is 28 days).
Pharmacokinetics (PK)
Time Frame: From Day 1, Day 2, Day 8, and Day 15 of Cycles 1 and 2, and Day 1 of Cycle 3 (each cycle is 28 days).
PK parameter: Area under Curve
From Day 1, Day 2, Day 8, and Day 15 of Cycles 1 and 2, and Day 1 of Cycle 3 (each cycle is 28 days).
Pharmacokinetics (PK)
Time Frame: From Day 1, Day 2, Day 8, and Day 15 of Cycles 1 and 2, and Day 1 of Cycle 3 (each cycle is 28 days).
PK parameter: Time of maximum observed plasma concentration (tmax)
From Day 1, Day 2, Day 8, and Day 15 of Cycles 1 and 2, and Day 1 of Cycle 3 (each cycle is 28 days).
Pharmacokinetics (PK)
Time Frame: From Day 1, Day 2, Day 8, and Day 15 of Cycles 1 and 2, and Day 1 of Cycle 3 (each cycle is 28 days).
PK parameter:Terminal half-life (t½)
From Day 1, Day 2, Day 8, and Day 15 of Cycles 1 and 2, and Day 1 of Cycle 3 (each cycle is 28 days).
Pharmacokinetics (PK)
Time Frame: From Day 1, Day 2, Day 8, and Day 15 of Cycles 1 and 2, and Day 1 of Cycle 3 (each cycle is 28 days).
PK parameter: Plasma Clearance (CL)
From Day 1, Day 2, Day 8, and Day 15 of Cycles 1 and 2, and Day 1 of Cycle 3 (each cycle is 28 days).
Pharmacokinetics (PK)
Time Frame: From Day 1, Day 2, Day 8, and Day 15 of Cycles 1 and 2, and Day 1 of Cycle 3 (each cycle is 28 days).
PK parameter: Volume of Distribution (Vd)
From Day 1, Day 2, Day 8, and Day 15 of Cycles 1 and 2, and Day 1 of Cycle 3 (each cycle is 28 days).
Pharmacokinetics (PK)
Time Frame: From Day 1, Day 2, Day 8, and Day 15 of Cycles 1 and 2, and Day 1 of Cycle 3 (each cycle is 28 days).
PK parameter: Mean residence time (MRT)
From Day 1, Day 2, Day 8, and Day 15 of Cycles 1 and 2, and Day 1 of Cycle 3 (each cycle is 28 days).
To assess adverse events of special interest (AESI) by measuring infusion reaction
Time Frame: Upto 90 days from the last dose of IMP
Upto 90 days from the last dose of IMP
To assess adverse events of special interest (AESI) by measuring cytokine release syndrome (CRS)
Time Frame: Upto 90 days from the last dose of IMP
Upto 90 days from the last dose of IMP
To assess adverse events of special interest (AESI) by measuring immune effector cell-associated neurotoxicity syndrome (ICANS)
Time Frame: Upto 90 days from the last dose of IMP
Upto 90 days from the last dose of IMP
To assess adverse events of special interest (AESI) by measuring hypersensitivity reaction
Time Frame: Upto 90 days from the last dose of IMP
Upto 90 days from the last dose of IMP
To assess the incidence of second primary malignancies reported as adverse events of special interest (AESI) occurring during the study treatment period and long-term follow-up.
Time Frame: From first dose of Investigational Medicinal Product (IMP) through end of study and follow-up (up to 2 years)
From first dose of Investigational Medicinal Product (IMP) through end of study and follow-up (up to 2 years)

Collaborators and Investigators

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

Sponsor

Myeloid Therapeutics

Collaborators

CREATE Medicines

Investigators

  • Study Director: Matthew Maurer, MD, Myeloid Therapeutics

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)

November 25, 2025

Primary Completion (Estimated)

January 31, 2027

Study Completion (Estimated)

March 30, 2028

Study Registration Dates

First Submitted

November 14, 2025

First Submitted That Met QC Criteria

January 2, 2026

First Posted (Actual)

January 12, 2026

Study Record Updates

Last Update Posted (Actual)

May 20, 2026

Last Update Submitted That Met QC Criteria

May 18, 2026

Last Verified

October 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • MTX-HER2-304

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

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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