EWSR1 Immunotherapy in Ewing Sarcoma and DSRCT (NCT07695311) | Clinical Trial Compass
Not Yet RecruitingPhase 1
EWSR1 Immunotherapy in Ewing Sarcoma and DSRCT
United States24 participantsStarted 2026-10
Plain-language summary
This study is for people who have high-risk Ewing sarcoma (ES), or a related Ewing's family tumor, desmoplastic small round cell tumor (DSRCT). The purpose of this study is to see if a new EWSR1 immunotherapy (a lipid nanoparticle coated with EWSR1 mRNA) which is given as a shot is safe and whether it can help the body's immune system better recognize and fight cancer.
This EWSR1 immunotherapy is designed to target a specific genetic change (EWSR1 fusion gene) that is found in cancer cells but not in normal, healthy cells. Because the EWSR1 gene is broken in cancer cells and the small protein it makes are only in the ES or DSRCT cancer cells, the goal of EWSR1 immunotherapy is to help the immune system identify and attack the cancer without harming normal cells. It is not yet approved by the Food and Drug Administration (FDA).
EWSR1 immunotherapy will be given as a shot into the muscle of the arm, leg, or buttock. If participants also receive botensilimab (4 doses after each EWSR1 immunotherapy shot) and balstilimab (an infusion every 2 weeks), these are given intravenously (IV) by a needle in the arm over 30 minutes. Participants in this study will receive treatment for about 6 months or until their cancer gets worse. Participants will remain in the study for follow-up for an additional year, for a total time of about 1.5 years in the study.
Who can participate
Age range
2 Years
Sex
ALL
See this in plain English?
AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Inclusion Criteria:
* Participants must have histologically confirmed Ewing sarcoma (ES) or desmoplastic small round cell tumor (DSRCT) and confirmation of fusion gene rearrangement and breakpoint EWSR1-FLI1, EWSR1-ERG, EWSR1-WT1, who have completed standard of care vincristine + doxorubicin + cyclophosphamide alternating with ifosfamide + etoposide (VDC/IE) and have relapsed or had metastatic disease or are very high-risk disease (Bosma groups C, D, E, and/or very poor necrosis after VDC/IE) are eligible. All EWSR1 immunotherapy monotherapy participants are expected to have completed standard of care VDC/IE chemotherapy with local control and have had end of therapy follow-up for \> 3 months.
* Participants must have demonstrated HLA (human leukocyte antigens) fit with an EWSR1 gene fusion peptide contained in the EWSR1 immunotherapy, as determined by HLA-binding analysis of peptides that span the EWSR1 fusion gene breakpoint and analysis of HLA fit to one of the constructs included in EWSR1 immunotherapy.
* Participants may have no evidence of active disease, detectable disease (e.g., lung metastases \< 1 cm or bone metastases), or measurable disease by iRECIST (Immune Response Evaluation Criteria in Solid Tumors) criteria. The presence of RECIST measurable disease is not required for study entry.
* At least 1 line of prior therapy (VDC/IE) is needed.
* Age. The first 3 EWSR1 immunotherapy monotherapy and combination therapy participants will be adults ≥ 18 years old. Afte…
Questions worth asking your doctor
Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.
1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?
Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.
Questions for the trial coordinator
The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.
1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?
A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.
What they're measuring
1
Safety of EWSR1 immunotherapy, measured by number of participants with grade 4 immunotherapy-related adverse events
Timeframe: Up to 6 months
2
Safety of combination therapy (EWSR1 immunotherapy + botensilimab + balstilimab), measured by number of participants with grade 3 drug related adverse events lasting greater than 1 week
Timeframe: Up to 6 months
3
Feasibility of EWSR1 immunotherapy monotherapy, measured by proportion of participants who receive doses
Timeframe: Up to 6 months
4
Feasibility of combination therapy (EWSR1 immunotherapy + botensilimab + balstilimab), measured by number of participants who receive at least 3 months of therapy