N-803 in Patients With Progressive 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.

NCT Number	NCT07261657
Lead Sponsor	Seth Pollack Collaborators: National Cancer Institute (NCI)
Conditions	Myxoid Liposarcoma, Round Cell Liposarcoma, Synovial Sarcoma
Enrollment	8 participants
Start Date	2026-04-13
Primary Completion	2030-09-02 (estimated)
Study Completion	2032-09-02 (estimated)
Updated on ClinicalTrials.gov	2026-06-15