Radioactive drug takes aim at Hard-to-Treat sarcoma
NCT ID NCT07156565
First seen Jun 26, 2026 · Last updated Aug 28, 2026 · Updated 4 times
Summary
This early-phase trial is testing a radioactive drug called [Ac225]RTX-2358 in 30 adults with advanced soft tissue sarcoma that has come back or stopped responding to prior treatment. The drug is given as an IV injection once every 8 weeks for up to 6 doses. The main goals are to check safety, find the best dose, and see if it can shrink tumors. Participants will also receive a diagnostic imaging agent to help identify tumors.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- A radioactive drug called [Ac225]RTX-2358, given by IV every 8 weeks
- What this could lead to
- If it works, this could point toward a new treatment option for advanced sarcoma that has stopped responding to other therapies.
- What could go wrong
- This is an early phase 1 trial with only 30 people, so it is primarily testing safety and dosing. The drug may not shrink tumors or may cause significant side effects.
This is an AI summary of the original study and may miss details. Read our disclaimer.
Study facts
What this study's own registry entry says, in plain language.
- Phase
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Phase 1
The first testing in people. Mainly checks safety and dose, usually in a small group.
- Participants
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About 48 people
The number the study aims to enrol. It can still change while the study runs.
- Started
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Nov 2025
- Expected to finish
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Jan 2032
An estimate. End dates often move.
- Lead sponsor
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A company
The lead sponsor is a pharmaceutical, biotech, or medical-device company.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
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18 years and older
- Sex
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Anyone
- Healthy volunteers
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Not accepted
This study is not open to healthy volunteers. The entry requirements below say who it is open to.
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Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
Inclusion Criteria: * 18 years of age or older. * History of relapsed or refractory soft tissue sarcoma. 1. Histological confirmation of sarcoma at any point since diagnosis 2. At least 1 prior treatment regimen * Measurable disease as per RECIST (v1.1) for soft tissue sarcoma that is also positive on FAPi PET/CT or PET/MRI scan. * ECOG performance status of 0 or 1. * Adequate Organ reserve and renal function as evidenced by: 1. Neutrophil count ≥ 1200 µL without granulocyte colony stimulating factor 2. Platelet count ≥ 100,000 µL 3. Hemoglobin ≥ 8 g/dL 4. Total bilirubin level ≤ 1.5 × upper limit of normal (ULN). 5. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤ 2.5 × ULN. 6. Calculated creatinine clearance ≥ 60 mL/min. 6. Coagulation parameters (prothrombin time, international normalized ratio and activated partial thromboplastin time) ≤ 1.5 × ULN 7. All patients (males and females of childbearing potential) must agree to practice 2 forms of highly effective contraceptive precautions to prevent pregnancy from the time consent is signed and throughout the trial. 8\. The patient or the patient's legal representative must be willing and able to provide written informed consent. Exclusion Criteria: * History of whole pelvic irradiation or lung irradiation. * History of radioligand therapy. * Treatment within 14 days prior to first administration with: 1. Palliative surgery or external beam radiation. 2. Approved anticancer therapy including chemotherapy or immunotherapy. 3. Any investigational therapy. 4. Any major surgery (e.g., requiring general anesthesia). * Patients who are scheduled for external beam radiation therapy or radioligand therapy during the study period. * Congestive heart failure \> Class II New York Heart Association Functional Classification, current pericarditis, myocardial infarction within 6 months, or symptomatic coronary artery disease. * Patients with uncontrollable incontinence. * Unstable or clinically significant concurrent medical condition that would, in the opinion of the Investigator, jeopardize the safety of a patient and/or their compliance with the protocol. * Active infection requiring systemic antibacterial/antibiotic, antifungal, or antiviral therapy. Chronic antiviral therapy for stable viral disease can be included. * History of active fibrotic condition. * Any active malignancy other than sarcoma that requires treatment. * Stable brain metastasis is allowed but documented untreated metastases to brain or meninges are excluded. * Currently pregnant or lactating. * Known allergy to any of the study drugs or their excipients. * Inability or unwillingness to comply with any of the required imaging studies or study assessments. * History of pneumonitis, interstitial lung disease, chronic obstructive pulmonary disease (COPD) or other inflammatory/fibrotic pulmonary condition.
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
How to take part
Only the study team decides who joins. These are the ways to reach them.
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The study's own enquiry address
This study publishes an address for enquiries. See it below .
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The places running it
6 sites in 2 countries. The list below names each one and where it is.
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The official record
ClinicalTrials.gov lists the study team's own contact details, including names and phone numbers. We don't republish those.
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A doctor treating you
A doctor who knows your case can contact a study site on your behalf, and can tell you whether this study is worth pursuing at all.
Contacts and locations
Show contact details
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Genom att skicka in godkänner du våra Användarvillkor
Locations
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Case Western
RECRUITINGCleveland, Ohio, 44106, United States
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MD Anderson Cancer Center
RECRUITINGHouston, Texas, 77230, United States
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Mayo Clinic
RECRUITINGRochester, Minnesota, 55905, United States
Contact Email: •••••@•••••
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Memorial Sloane Kettering Cancer Center
RECRUITINGNew York, New York, 10065, United States
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Princess Margaret Cancer Centre
RECRUITINGToronto, Ontario, M5G 2M9, Canada
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UCLA
RECRUITINGLos Angeles, California, 90095, United States
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Other studies related to the condition(s) this trial covers.
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- Immunotherapy boosts chemo against rare sarcomas?
- New mRNA shot targets Hard-to-Treat cancers in early human test
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- New drug cocktail shows promise in slowing rare sarcoma