To Evaluate the Efficacy and Safety of Naxitamab in Patients With Refractory Ewing's Sarcoma (Butterfly)

To Evaluate the Efficacy and Safety of Naxitamab in Patients With Refractory Ewing's Sarcoma

To Evaluate the Efficacy and Safety of Naxitamab in Patients With Refractory Ewing's Sarcoma (Butterfly) (NCT05968768) is a Phase 2 interventional studying Ewing Sarcoma, sponsored by Anna Raciborska. RECRUITING as of the most recent ClinicalTrials.gov update. Talk to your doctor before contacting the trial site.

About This Trial

Prospective, interventional, open, randomized, national, multicenter, non-commercial trial

What Stage of Research Is This?

Phase 2 trials evaluate whether a treatment actually works against Ewing Sarcoma and continue monitoring side effects. Phase 2 enrolls larger groups (typically 100–300 patients) and produces the first real efficacy signal. A successful Phase 2 readout is what unlocks the much larger Phase 3 confirmatory trials needed for FDA approval.

This trial is currently recruiting participants. The sponsor has registered the study with ClinicalTrials.gov as actively enrolling, which means new applicants who meet the eligibility criteria can be considered for screening. Trial status can change between updates — confirm current recruiting status with the study contact before traveling for a screening visit.

With a target enrollment of 24 participants, this is a small study — typical of early-phase research, rare-disease trials, or pilot studies designed to generate preliminary signal before a larger study is launched.

Who May Be Eligible (Plain English)

Who May Qualify: 1. Histologically proven Ewing sarcoma of the bone or soft tissues. 2. Subject's archival tumour sample (formalin-fixed, paraffin-embedded; FFPE) available for evaluation of GD2 expression. 3. Documented disease progression (during or after completion of at least one line treatment) or any subsequent recurrence. 4. GD2 positive tumor assessed by IHC. 5. Age ≥ 2 years and ≤ 21 years. 6. expected to live at least 12 weeks from the time willing to sign a consent form was signed. 7. Previous systemic anticancer treatment completed ≥ 3 weeks, major surgery ≥ 2 weeks, and radiation therapy ≥ 4 weeks prior to study enrollment. 8. Recovered from adverse effects of prior surgery, radiotherapy, or Clinical trial protocol BUTTERFLY version 1.0 of 30.09.2022 r.anti-neoplastic therapy at the discretion of the investigator. 9. Signing of willing to sign a consent form for trial participation (including for naxitamab treatment) according with current legal regulations. 10. Consent to the use of effective contraception throughout the period of the study and a minimum of 1 year after discontinuation of study treatment in patients at puberty and sexual maturity Who Should NOT Join This Trial: 1. Failure to meet any of the inclusion criteria. 2. Not eligible to IT. 3. Previous treatment with an anti-GD2 antibody. 4. Hypersensitivity to the study drugs or any of their ingredients (covers IT and naxitamab). 5. Simultaneous treatment with other drugs which might interact with naxitamab or IT regimen. 6. Persistent toxicity related to prior therapy, making it impossible to treat with naxitamab. 7. Significant cardiac conduction abnormalities, including known familial prolonged QT syndrome, or screening corrected QT interval (QTc) \>480 msec. 8. Symptoms of congestive heart failure or left ventricular ejection fraction \<50%. ...See full criteria on ClinicalTrials.gov Always talk to your doctor about whether this trial is right for you.

These are translations of the protocol\'s inclusion and exclusion criteria, simplified for patients and caregivers. The original clinical text appears below. Eligibility is ultimately confirmed by the trial site\'s screening process — this summary is a starting point for a conversation with your doctor, not a final determination.

Original Eligibility Criteria

View original clinical language

Inclusion Criteria: 1. Histologically proven Ewing sarcoma of the bone or soft tissues. 2. Subject's archival tumour sample (formalin-fixed, paraffin-embedded; FFPE) available for evaluation of GD2 expression. 3. Documented disease progression (during or after completion of at least one line treatment) or any subsequent recurrence. 4. GD2 positive tumor assessed by IHC. 5. Age ≥ 2 years and ≤ 21 years. 6. Life expectancy of at least 12 weeks from the time informed consent was signed. 7. Previous systemic anticancer treatment completed ≥ 3 weeks, major surgery ≥ 2 weeks, and radiation therapy ≥ 4 weeks prior to study enrollment. 8. Recovered from adverse effects of prior surgery, radiotherapy, or Clinical trial protocol BUTTERFLY version 1.0 of 30.09.2022 r.anti-neoplastic therapy at the discretion of the investigator. 9. Signing of informed consent for trial participation (including for naxitamab treatment) according with current legal regulations. 10. Consent to the use of effective contraception throughout the period of the study and a minimum of 1 year after discontinuation of study treatment in patients at puberty and sexual maturity Exclusion Criteria: 1. Failure to meet any of the inclusion criteria. 2. Not eligible to IT. 3. Previous treatment with an anti-GD2 antibody. 4. Hypersensitivity to the study drugs or any of their ingredients (covers IT and naxitamab). 5. Simultaneous treatment with other drugs which might interact with naxitamab or IT regimen. 6. Persistent toxicity related to prior therapy, making it impossible to treat with naxitamab. 7. Significant cardiac conduction abnormalities, including known familial prolonged QT syndrome, or screening corrected QT interval (QTc) \>480 msec. 8. Symptoms of congestive heart failure or left ventricular ejection fraction \<50%. 9. Inadequate pulmonary function defined as evidence of dyspnea at rest, exercise intolerance, and/or chronic oxygen requirement. In addition, room air pulse oximetry \< 94% and/or abnormal pulmonary function tests if these assessments are clinically indicated. 10. Requirement, or likely requirement, for corticosteroids at doses \>10 mg prednisolone (or equivalent) per day or other immunosuppressive agents. 11. Diagnosis of other malignancies before study inclusion. 12. Planning to become pregnant (while being treated with IT or naxitamab), pregnancy or breastfeeding. 13. Other acute or persistent disorders, behaviors or abnormal laboratory test results, which might increase the risk related to the participation in this clinical trial or to taking the study drug, or which might influence the interpretation of the study results, or which, in the investigator's opinion, disqualify a patient from participating in the tri

Treatments Being Tested

DRUG

Naxitamab

Naxitamab will be used only in a hospital setting and must be administered under the supervision of a doctor with experience in the use of oncological therapies. The medicinal product must be administered by a healthcare professional prepared to deal appropriately with severe allergic reactions, including anaphylaxis, in an environment that provides immediate, full access to resuscitation. The patient should have 2 well-functioning IV accesses before any naxitamab treatment is initiated. The solution should be administered through a peripheral or central intravenous catheter. Other concomitant intravenous medicinal products should be administered through separate intravenous access. Before the start of each infusion, premedication will be carried out.

Locations (2)

Trial sites listed on ClinicalTrials.gov for this study. Site activation status can vary — confirm with the specific site before traveling for a screening visit.

Mother and Child Institute

Warsaw, Mazowian, Poland

Wroclaw Medical University

Wroclaw, Poland

How to Talk to Your Doctor About This Trial

Bring the printable summary of this trial — including the NCT ID (NCT05968768), the sponsor (Anna Raciborska), and the key eligibility criteria — to your next appointment. Your doctor can review the inclusion and exclusion criteria against your medical history, lab values, and current treatments to assess whether you are likely to qualify. They can also help you weigh whether trial participation makes sense alongside your existing care plan.

Useful questions to walk through together: What does the trial protocol require beyond standard care? How long is the active treatment phase, and how long is follow-up? Are there study visits at sites I can reach? Who pays for the trial-specific procedures, and who pays for standard-of-care portions? See our 25 questions to ask about clinical trials guide for a more complete checklist.

Authoritative Sources

The official record for this trial lives on ClinicalTrials.gov — the federal registry maintained by the National Library of Medicine at NIH. For background on how this trial fits into the FDA approval pathway, see the FDA drug approval process. For oncology-specific guidance for patients considering trials, the National Cancer Institute publishes patient-oriented overviews. International trial registries are aggregated by the WHO ICTRP.

Frequently Asked Questions

What is the NCT05968768 clinical trial studying?

Prospective, interventional, open, randomized, national, multicenter, non-commercial trial The full protocol is registered on ClinicalTrials.gov and includes the primary outcome measures, eligibility criteria, and study endpoints.

Who can participate in NCT05968768?

Eligibility for this trial depends on the specific inclusion and exclusion criteria set by the sponsor. The plain-English summary above translates the most important criteria into accessible language; the official clinical text is preserved in the collapsible section underneath. Whether you fit any specific trial is a medical decision your doctor needs to confirm — bring the trial information to your treating physician for a full review against your medical history.

How do I contact the trial site for NCT05968768?

Contact information registered with ClinicalTrials.gov is shown in the sidebar of this page. Before reaching out, confirm with your treating physician that this trial is appropriate for your situation. The trial site will then walk you through the screening process to determine final eligibility.

Is participating in a clinical trial safe?

Clinical trials in the United States are regulated by the FDA and overseen by Institutional Review Boards (IRBs) that review the protocol for safety. Risk varies by trial — Phase 1 studies test new treatments in humans for the first time, while Phase 3 trials use treatments that have already passed earlier safety screening. The informed consent document for any specific trial details the known risks and what to expect. Discuss those risks with your physician before deciding whether to participate.

Where can I verify the data on this page?

Every detail on this page comes directly from the ClinicalTrials.gov API. Click "View on ClinicalTrials.gov" in the sidebar to see the official, unmodified record. The federal record is always authoritative; this page is a structured presentation with a plain-English eligibility translation. For background on how clinical trials are regulated, see the FDA drug approval process documentation.

How This Page Is Built

Every field on this page is pulled directly from the ClinicalTrials.gov API v2 — no estimates, no proxies. The plain-English eligibility translation is generated from the original protocol text and reviewed for fidelity to the underlying clinical criteria. The original clinical text remains visible in the collapsible section above so users and clinicians can verify the translation. Read the full methodology for the data pipeline and known limitations.

Source: ClinicalTrials.gov API v2 record for NCT05968768. Maintained by the National Library of Medicine at NIH. Public domain. Cite as: "TrialFinderData. NCT05968768. Data: ClinicalTrials.gov."

Medical disclaimer: This page is informational, not medical advice. Talk to your doctor about whether a clinical trial is right for you.

Last updated 2026-06-07 · Data from ClinicalTrials.gov.