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Myxoid LiposarcomaEarly Phase 1NCT07261657

N-803 in Patients With Progressive Synovial Sarcoma and Myxoid/Round Cell Liposarcoma Previously Treated With Adoptive Cellular Therapy

A Early Phase 1 study testing Biospecimen Collection, Computed Tomography and Leukapheresis in people with Myxoid Liposarcoma and Round Cell Liposarcoma, run by Seth Pollack at 1 site in United States.

Recruiting

Looking for participants now. Contact the study team or a site below to ask about taking part.

Sites and contacts
Official record
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Trial summary

This early phase I trial tests the safety and how well N-803 works in treating patients with synovial sarcoma (SS) or myxoid/round cell liposarcoma (MRCL) that is growing, spreading, or getting worse (progressive) after being treated with adoptive cellular therapy (ACT) using T-cell receptor therapy (T-CRT). Read more about this study

Who is it for?
Ages 18 to 80 years
What is being tested?
Biospecimen Collection, Computed Tomography and Leukapheresis
Type of treatment
Surgery or procedure
Could I receive a placebo?
No, everyone receives an active treatment
How many people
8 participants
Where
1 siteUnited States
Study dates
13 Apr 2026to 2 Sep 2032
Phase
Early Phase 1
Are there results?
Not yet: the study is under way

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 to 80 years
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • Patients must have histologically or cytologically confirmed Synovial Sarcoma (SS) and/or Myxoid/Round Cell Liposarcoma (MRCL) who have progressed after ACT using TCR-T.
  • Patients must have been treated with a TCR-T product that can be assessed per medical history and/or discretion of the principal investigator. This includes the FDA approved Afamitresgene autoleucel but also other products at the discretion of the principal investigator.
  • Note on References to Letetresgene Autoleucel and Afamitresgene Autoleucel: This study does not involve active treatment with TCR-T cell therapies, including Letetresgene autoleucel or Afamitresgene autoleucel. The investigational drug of this study is N-803. Please see Section 4.3.3 for more information.
  • Patients must have measurable disease according to RECIST v1.1. See Appendix A for RECIST v1.1 criteria.
  • Patients must have shown clinical benefit on at least one scan post ACT using TCR-T, (SD, PR, CR), as determined by the treating investigator.
  • Patients must be aged ≥ 18 to 80 at time of registration.
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  • Patients must have a performance status of >70% on the Karnofsky Scale (see Appendix A) or < 2 on the ECOG Performance Scale (see Appendix B).
  • Patients must be able to undergo leukapheresis per institutional standards. For patients receiving leukapheresis at the Rube Walker Blood Center, see Appendix F for reference document guidance and Rube Walker Blood Center leukapheresis eligibility criteria.
  • Patients must have adequate organ and bone marrow function as defined below within screening window of 28 days up until Pre-Dose Leukapheresis:
  • Laboratory Test Value
  • Absolute Neutrophil Count (ANC) ≥ 500/mcL Hemoglobin (Hgb) ≥ 7.5 g/dL Platelets (PLT) ≥ 40,000/mcL Total bilirubin ≤ Institutional upper limit of normal (ULN) AST (SGOT) ≤ 1.5 x institutional ULN ALT (SGPT) ≤ 1.5 x institutional ULN ALP (alkaline phosphatase) ≤ 2.5 institutional ULN Serum Creatinine ≤ 2.0 mg/dL or 177 μmol/L or creatinine clearance ≥ 40 mL/min (using the Cockcroft-Gault formula below):
  • Cockcroft-Gault Formula:
  • Female = [(140 - age in years) × weight in kg × 0.85] / [72 × serum creatinine in mg/dL]
  • Male = [(140 - age in years) × weight in kg × 1.00] / [72 × serum creatinine in mg/dL]
  • Unless the patient has documented Gilbert's syndrome. Patients with Gilbert syndrome may be eligible with total bilirubin up to 3 × ULN, provided direct bilirubin is within normal limits and per investigator discretion.
  • Prior growth factors are allowed per treating investigator discretion (i.e. erythropoietin (EPO), Granulocyte-Macrophage Colony-Stimulating Factors (GM-CSF) such as Sargramostim, Platelet-Derived Growth Factor (PDGF), Granulocyte Colony-Stimulating Factors (G-CSF) including Filgrastim, Darbepoetin Alfa are allowed per standard of care. Refer to Section 4.2 for more information on supportive care measures.
  • Note: All laboratory value permitted departures (described in the above table with a different ULN) should be clearly documented by the treating investigator in the sources.
  • Note: Patients do not need to meet lab eligibility requirements after screening. For days of leukapheresis, refer to institutional guidelines for lab eligibility for leukaphereses (see Appendix F for Rube Walker Blood Center leukapheresis eligibility criteria).
  • Note: The institutional upper limit refers to the reference range upper limit established by the institution where the laboratory tests were performed.
  • The effects of N-803 on the unborn fetus are unknown. For this reason, patients of child-bearing potential (POCBP) and their partners with sperm-producing reproductive capacity must agree to use adequate contraception from start of treatment, for the duration of study participation, and for 7 months following completion of N-803 therapy. Should a POCBP become pregnant or suspect they are pregnant while they or their partner are participating in this study, they should inform their treating physician immediately. Patients with sperm-producing reproductive capacity (PWSPRC) treated or enrolled on this protocol must also agree to use adequate contraception with partners of childbearing potential from time of informed consent, for the duration of study participation, and 7 months after completion of administration.
  • Note: A POCBP is any patient (regardless of gender, sexual orientation, having undergone a tubal ligation, or remaining celibate by choice) with an egg-producing reproductive tract who meets the following criteria:
  • Has not undergone a hysterectomy or bilateral oophorectomy
  • Has had menses at any time in the preceding 12 consecutive months (and therefore has not been naturally postmenopausal for > 12 months)
  • POCBP must have a negative pregnancy test during screening and per the study schedule. See Study Procedures in Section 5 for more information.
  • Patients must have the ability to understand and the willingness to sign a written informed consent document and comply with the study requirements.

Who cannot join

  • Patients who have not recovered from adverse events due to prior anti-cancer therapy (i.e., have residual toxicities > Grade 1) with the exception of alopecia, neuropathy and other non-significant adverse events per NCI CTCAE v 5.0 as deemed by the principal investigator.
  • Patients with high risk of bleeding, as determined by treating investigator. Note: If patients are on anticoagulants, the investigator will determine if patient can continue anticoagulants throughout the study, or if their dosage needs to be changed until completion of both leukapheresis procedures.
  • Patients who have received other IL-15 treatments since receiving TCR-T cells to the start of study treatment (C1D1).
  • Note: Prior growth factors are allowed per treating investigator discretion (i.e. erythropoietin (EPO), Granulocyte-Macrophage Colony-Stimulating Factors (GM-CSF) such as Sargramostim, Platelet-Derived Growth Factor (PDGF), Granulocyte Colony-Stimulating Factors (G-CSF) including Filgrastim, Darbepoetin Alfa
  • Patients with new or progressing brain metastases. Note: Patients with treated brain metastases that are stable in the opinion of the treating investigator are eligible.
  • Known significant cardiovascular disease, such as New York Heart Association cardiac disease (Class II or greater, see Appendix C), myocardial infarction within 3 months prior to Pre-Dose Leukapheresis, unstable arrhythmias, or unstable angina. To be eligible for this trial, patients should be class 2B or better. See Appendix C for more information.
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  • Patients who have a history of allergic reactions attributed to compounds of similar chemical or biologic composition to N-803 or history of severe allergic, anaphylactic, or other hypersensitivity reactions to chimeric or humanized antibodies or fusion proteins.
  • Participants who, in the opinion of the investigator, are unable to safely or feasibly receive subcutaneous injections of N-803. Examples include:
  • Absence of suitable subcutaneous tissue for injection (e.g., due to cachexia, scarring, or anatomical limitations).
  • Known history of allergic reactions attributed to compounds of similar chemical or biologic composition to N-803, or history of severe allergic, anaphylactic, or other hypersensitivity reactions to chimeric or humanized antibodies or fusion proteins.
  • Active skin conditions or infections at potential injection sites.
  • Physical or psychological inability to tolerate subcutaneous injection procedures (e.g., severe needle phobia, movement disorders).
  • Medical contraindications to subcutaneous administration (e.g., bleeding disorders, severe dermatologic conditions).
  • Any other factors that, in the judgment of the investigator, would interfere with safe and feasible administration of subcutaneous injections.
  • Major surgical procedure (as defined in Appendix E, e.g., GI surgery, removal or biopsy of brain metastasis), other than for diagnosis or known need for a major surgical procedure while on study treatment.
  • Note: Patients must have fully recovered from complete wound healing from said surgery prior to first study assessment, in the opinion of the treating investigator.
  • Note: Surgery and radiation are allowed after completion of Cycle 5 per discretion of treating investigator (CT scan and N-803 administration at Cycle 5 must have already occurred).
  • Systemic autoimmune disease currently requiring treatment (e.g., lupus erythematosus, rheumatoid arthritis, Addison's disease, or autoimmune disease associated with lymphoma). The patient must have been off treatment for 90 days from registration.
  • History of organ transplant requiring immunosuppression; or history of pneumonitis or interstitial lung disease requiring treatment with systemic steroids; or a history of receiving systemic steroid therapy or any other immunosuppressive medication ≤ 3 days prior to study initiation. Daily steroid replacement therapy (e.g., prednisone or hydrocortisone at doses of ≤ 10 mg/day of prednisone (or equivalent)) and corticosteroids used to manage AEs are permitted.
  • Patients who require immunosuppressive agents during their study participation are ineligible, except:
  • Use of physiologic doses of systemic steroid replacement is permitted at doses of ≤ 10 mg/day of prednisone (or equivalent, e.g., dexamethasone 1.5 mg, methylprednisolone 8 mg, or hydrocortisone 40 mg).
  • Local steroids, including topical steroids (e.g., hydrocortisone, clobetasol), nasal steroids (e.g., fluticasone, mometasone), or inhaled steroids (e.g., budesonide, beclomethasone).
  • Limited courses (< 1 week) of systemic steroids (≤ 10 mg/day of prednisone or equivalent) (e.g, in patients with exacerbations of reactive airway disease or anaphylaxis in patients who have known contrast allergies).
  • Immunosuppressive treatments to optimally manage immune-related AEs as clinically indicated
  • Serious uncontrolled concomitant disease that would contraindicate the use of the investigational drug used in this study or that would put the patient at high risk for treatment-related complications.
  • Patients who have an uncontrolled intercurrent illness including, but not limited to any of the following:
  • Hypertension that is not controlled on medication
  • Ongoing or active infection requiring systemic treatment including:
  • Known active infection with acute or chronic hepatitis B or C, known active human immunodeficiency virus (HIV), or acquired immunodeficiency syndrome
  • Exception: uncomplicated urinary tract infections (or sinus infections and are on antibiotics)
  • (AIDS)-related illness
  • Symptomatic congestive heart failure
  • Unstable angina pectoris
  • Cardiac arrhythmia
  • Psychiatric illness/social situations that would limit compliance with study requirements
  • Any other illness or condition that the treating investigator feels would interfere with study compliance or would compromise the patient's safety or study endpoints
  • Patients with a prior or concurrent malignancy whose natural history or treatment has the potential to interfere with the safety or efficacy assessment of the investigational regimen except the following:
  • Basal cell carcinoma of the skin
  • Squamous cell carcinoma of the skin
  • In situ cervical cancer that has undergone potentially curative therapy - Patient is pregnant or nursing. Note: Pregnant patients are excluded from this study because N-803 is an interleukin-15 (IL-15) receptor agonist with potential for teratogenic or abortifacient effects. Because there is an unknown but potential risk for adverse events in nursing infants secondary to treatment of the mother with N-803, breastfeeding should be discontinued if the mother is treated with N-803.
  • Note: Serum test will be conducted at screening (serum pregnancy test (human chorionic gonadotropin [β-HCG]). See Study Procedures in Section 5 for more information.
  • Other conditions which, in the opinion of the Investigator, would compromise the safety of the patient or the patient's ability to complete the study.
  • Patients who need to be on concurrent anticancer treatment (e.g., chemotherapy, immunotherapy, cytokine therapy [except erythropoietin]) throughout participation in the study.
  • Patients who have had prior use of narrow therapeutic index drugs that are substrates of major CYP450 enzymes within 14 days of first study drug administration per discretion of the treating investigator, including but not limited to:
  • Tacrolimus
  • Cyclosporine
  • Sirolimus
  • Everolimus
  • Warfarin
  • Phenytoin
  • Midazolam
  • Tamoxifen
  • Codeine
  • Erlotinib
  • Patients who have had prior use concomitant medications that prolong the QT/QTc interval within 14 days of first study drug administration visit per discretion of the treating investigator.
  • Patients who have had prior biologic therapies or chemotherapy within 28 days of Pre-Dose Leukapheresis visit, or radiation therapy within 14 days of Pre-Dose Leukapheresis visit.
  • Patient must have reviewed and signed the informed consent document before any study activities may occur. Registration of patients is completed in NOTIS. Please refer to Section 11.3 for details on the registration process.

Trial locations and contacts

1 site in 1 country. Contact the study team or a site near you to ask about taking part.

Study Coordinator contact

3126951301

cancer@northwestern.edu

United States1 site, 1 recruiting

  • Northwestern University

    Chicago, Illinois, 60611

    Seth M. Pollack, MD, 312-695-6180, seth.pollack@northwestern.edu

    Seth M. Pollack, MD

    Recruiting

Other trials in United States

About this study

Official title: A Pilot Trial of N-803 in Patients With Synovial Sarcoma and Myxoid/Round Cell Liposarcoma Previously Treated With Adoptive Cellular Therapy

This early phase I trial tests the safety and how well N-803 works in treating patients with synovial sarcoma (SS) or myxoid/round cell liposarcoma (MRCL) that is growing, spreading, or getting worse (progressive) after being treated with adoptive cellular therapy (ACT) using T-cell receptor therapy (T-CRT). Synovial sarcoma is a rare, slow-growing cancer that affects the soft tissues, like muscles or ligaments near the joints. Myxoid/round cell liposarcoma is a rare type of soft tissue sarcoma cancer that originates from fat cells usually in the arms and legs. N-803 is a type of immunotherapy-a treatment that helps patients' own immune system fight cancer, and it is made up of a natural protein called interleukin-15 (IL-15) that is important for growing and activating immune cells. Studies have shown that patients can progress after initially responding to TCR-T, so this trial will use N-803 to stimulate rare persisting cells (cells that survive treatment and cause treatment failure and disease relapse) to make them work better at attacking the cancer. Adoptive cell therapy is a type of therapy that uses a patient's own immune cells to fight cancer. T-cell receptor therapy is a type of ACT that can recognize better recognize and bind to protein in cancer cells. Giving N-803 may be safe and tolerable in patients with SS or MRCL.

Read the detailed description

CO-PRIMARY OBJECTIVES:

  1. Assess whether nogapendekin alfa inbakicept (N-803) treatment in patients with SS and MRCL that received prior ACT using TCR-T cells expands rare persisting transferred TCR-T cells.

II. Assess the safety of N-803 in patients with SS and MRCL that received prior ACT using TCR-T cells.

SECONDARY OBJECTIVES:

  1. Assess for preliminary evidence of N-803 clinical activity by imaging in patients with SS and MRCL that received prior ACT using TCR-T cells.

II. Evaluate 6-month progression free survival (PFS) of patients with SS and MRCL treated with N-803 and that have received prior ACT using TCR-T cells.

III. Evaluate median progression-free survival (PFS) of patients with SS and MRCL treated with N-803 and that received prior ACT using TCR-T cells.

EXPLORATORY OBJECTIVES:

  1. To perform detailed phenotypic analysis of the persisting transferred T cells in pre-dose and on-treatment leukapheresis samples of patients with SS and MRCL treated with N-803 and that received prior ACT using TCR-T cells.

II. To perform detailed analysis of other immunologic subsets, including natural killer (NK) cells and monocytes, following patients with SS and MRCL treated with N-803 and that received prior ACT using TCR-T cells.

OUTLINE:

Patients receive N-803 subcutaneously (SC) on day 1 of each cycle. Cycles repeat every 14 days for up to 52 cycles in the absence of disease progression or unacceptable toxicity. Patients also undergo leukapheresis during screening up until day 1 cycle 1 and during treatment on day 8 cycle 4. Patients also undergo computed tomography (CT), chest x-ray, or magnetic resonance imaging (MRI) as well as blood sample collection throughout the trial.

After completion of study treatment, patients are followed up at 30 days.

Being tested
Biospecimen Collection, Computed Tomography, Leukapheresis, Magnetic Resonance Imaging, Nogapendekin Alfa Inbakicept
Medical subject headings
Liposarcoma, Myxoid, Sarcoma, Synovial

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • Biospecimen CollectionProcedure or surgery

    Also called Biological Sample Collection, Biospecimen Collected, Specimen Collection

    Undergo blood sample collection

  • Computed TomographyProcedure or surgery

    Also called CAT, CAT Scan, Computed Axial Tomography, Computerized Axial Tomography

    Undergo CT

  • LeukapheresisProcedure or surgery

    Also called Leukocyte Adsorptive Apheresis, Leukocytopheresis, Therapeutic Leukopheresis, White Blood Cell Reduction Apheresis

    Undergo leukapheresis

  • Magnetic Resonance ImagingProcedure or surgery

    Also called Magnetic Resonance, Magnetic Resonance Imaging (MRI), Magnetic resonance imaging (procedure), Magnetic Resonance Imaging Scan

    Undergo MRI

  • Nogapendekin Alfa InbakiceptBiological

    Also called ALT 803, ALT-803, ALT803, Anktiva

    Given SC

  • X-Ray ImagingProcedure or surgery

    Also called Conventional X-Ray, Diagnostic Radiology, Medical Imaging, X-Ray, Plain film radiographs

    Undergo chest x-ray

Study groups in NCT07261657
Study groupRoleWhat they receive
Treatment (N-803, leukapheresis)ExperimentalPatients receive N-803 SC on day 1 of each cycle. Cycles repeat every 14 days for up to 52 cycles in the absence of disease progression or unacceptable toxicity. Patients also undergo leukapheresis during screening up until day 1 cycle 1 and during treatment on day 8 cycle 4. Patients also undergo CT, chest x-ray, or MRI as well as blood sample collection throughout the trial.
Receives: Procedure: Biospecimen Collection; Procedure: Computed Tomography; Procedure: Leukapheresis; Procedure: Magnetic Resonance Imaging; Biological: Nogapendekin Alfa Inbakicept; Procedure: X-Ray Imaging

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. The expansion of rare persisting transferred T-cell receptor therapy

    Will be assessed using T-cell receptor sequencing or flow cytometry.

    Measured: Before and after eight weeks of N-803 therapy

  2. Incidence of adverse events

    Will be determined by the incidence, severity, and attribution of adverse events graded per National Cancer Institute Common Terminology Criteria for Adverse Events version 5.0.

    Measured: Up to 30 days after the last administration of N-803

Secondary outcomes (3)

  1. Overall response rate

    Will be defined by Response Evaluation Criteria in Solid Tumors version 1.1. Will be estimated with a two-sided 95% confidence interval using the Clopper-Pearson method.

    Measured: Up to 4 years

  2. Six-month progression-free survival (PFS)

    Defined as the proportion of patients who remain alive and progression-free at six months (± 2 weeks) from treatment initiation. The Kaplan-Meier method will be used to estimate the six-month PFS rate, and a corresponding 95% confidence interval will be reported.

    Measured: Up to 4 years

  3. Median PFS

    Kaplan-Meier curves will be reported descriptively, and median PFS will only be interpreted if the survival function drops below 50% with sufficient events to support stable estimation.

    Measured: Up to 4 years

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted3 Dec 2025
  2. Study start13 Apr 2026
  3. Primary completion2 Sep 2030 (estimated)
  4. Study completion2 Sep 2032 (estimated)

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Early Phase 1
Primary purpose
Treatment
Allocation
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrolment
8 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT07261657
Sponsor's protocol ID
NU 25S06
Other IDs
NCI-2025-08495, STU00224911, NU 25S06, P30CA060553
Status last verified
Aug 2026
First submitted
21 Nov 2025
Last updated
27 Aug 2026
Results posted
No
Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No

Questions about this trial

What is this clinical trial studying?

A Early Phase 1 study testing Biospecimen Collection, Computed Tomography and Leukapheresis in people with Myxoid Liposarcoma and Round Cell Liposarcoma, run by Seth Pollack at 1 site in United States.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 25 inclusion and 57 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: looking for participants now, as of the sponsor's last update on 27 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Early Phase 1 (sometimes called Phase 0) studies give a very small amount of a treatment to a few people, mainly to see how the body handles it.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

Contact Study Coordinator (3126951301, cancer@northwestern.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

The expansion of rare persisting transferred T-cell receptor therapy (time frame: Before and after eight weeks of N-803 therapy). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT07261657.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 27 Aug 2026.

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