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Study of IMA203 and mRNA-4203 for Melanoma and Synovial Sarcoma

This study is testing the safety and effectiveness of two treatments, IMA203 and mRNA-4203, for people with advanced cutaneous melanoma (a type of skin cancer) or synovial sarcoma (a rare soft tissue cancer). You might be able to join if your cancer has spread or cannot be removed by surgery, and if your body has a specific genetic marker called HLA-A*02:01. Researchers will be looking for side effects and how well the combination treatment shrinks tumors. The study plans to enroll 15 participants.

Study design
This is an open-label (meaning you and your doctors will know what treatments you are receiving) Phase 1a/b study. It is not comparing the treatment to another group.
What's involved
You would receive chemotherapy before a single infusion of IMA203, followed by low-dose IL-2 for up to 10 days. mRNA-4203 would be given starting 15 days after IMA203, for a total of 12 cycles.
Compensation
Not stated in the trial record.
Follow-up
Researchers will monitor you for side effects and other changes for one year after your IMA203 infusion.

AI-generated from the public study record. Only the study team can confirm whether you're eligible — confirm details with them before making decisions.

NCT06946225

ACTengine® IMA203 Combined With mRNA-4203

Recruiting
PHASE1Ages 18+InterventionalTreatment
Immatics US, Inc.
~15 participants
Updated 2026-01-08 on ClinicalTrials.gov
What's tested:IMA203mRNA-4203

At a glance

Recruiting sites
4 of 4 listed sites are recruiting right now
RecruitingSuspended, closed, or not yet open
What they're measuring
Number of participants with dose-limiting toxicities (DLTs)
Measured over one year post infusion of IMA203
+1 more outcome measured

Conditions

Cutaneous Melanoma
Synovial Sarcoma

Explore related trials

Cutaneous MelanomaSynovial SarcomaHLA Class I Histocompatibility Antigen, A-0201 Alpha Chain

Where it's being run

4 sites across 4 states
California1
Massachusetts1
New York1
Texas1

Who to contact

Immatics US, Inc.
[email protected]
+1 346 204-5400
Email the study team

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Do you actually qualify for this trial?

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Eligibility criteria

Inclusion

Pathologically confirmed and documented cutaneous melanoma (CM) or synovial sarcoma (SS) with unresectable or metastatic disease
HLA-A\*02:01 positive
Adequate selected organ function per protocol
Eastern Cooperative Oncology Group (ECOG) performance status 0-1
Measurable disease according to Response Evaluation Criteria in Solid Tumors (RECIST 1.1)
Life expectancy more than 5 months
CM participants who must have disease progression (resistance, toxicity) on or after at least one PD-1 inhibitor
SS participants must have received (or declined) at least one line of treatment (including SoC) and are still in need of further systemic therapy.
Female participants of childbearing potential must use adequate contraception prior to trial entry until 12 months after the infusion of IMA203 and 15 days after the last mRNA 4203 dose administration

Exclusion

History of other malignancies (except for adequately treated basal or squamous cell carcinoma or carcinoma in situ) within the last 3 years
Pregnant or breastfeeding
Serious autoimmune disease
History of cardiac conditions as per protocol
Prior allogenic stem cell transplantation or solid organ transplantation
Concurrent severe and/or uncontrolled medical disease that could compromise participation in the study
History of hypersensitivity to cyclophosphamide, fludarabine, or IL-2
History of hypersensitivity to mRNA-based medicines
Positive for HIV infection or with active hepatitis B virus (HBV) or active hepatitis C virus (HCV) infection
Any condition contraindicating leukapheresis
Participants with lactate dehydrogenase (LDH) greater than threshold allowed per protocol
Participants with active brain metastases prior to lymphodepletion
Concurrent treatment in another clinical trial or a device trial that could interfere with the IMA203 treatment
Participants with renal impairment AND reduced bone marrow reserve per protocol

What this trial measures

  • Number of participants with dose-limiting toxicities (DLTs)one year post infusion of IMA203

    Number of DLTs will be used to determine the maximum tolerated dose (MTD) and/or recommended dose for extension (RDE) after treatment with IMA203 product in combination with mRNA-4203

  • Number of treatment emergent adverse events (AEs), AEs of special interest, serious AEs (SAEs), changes in laboratory parameters and vital signs, and frequency of dose interruptions, reductions and discontinuationsone year post infusion of IMA203

    Used to evaluate safety and tolerability of treatment with IMA203 in combination with mRNA-4203