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

August 19, 2026 updated by: Anna Raciborska

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

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

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

The study includes:

  1. Biology screening: to estimate expression on GD2 on Ewing sarcoma cells from tumor tissue from archival material. Availability of tumor tissue is required for pre-screening testing to determine GD2 expression. To be screened for potential enrollment into the study patients or their legal representatives must have signed the pre-screening informed consent form (ICF) to consent to using their archival tumor sample to test the expression of GD2 in their tumor. The expression level of GD2 will be characterized in tumor tissue by immunohistochemistry (IHC) at a local and a central diagnostic testing laboratory.
  2. Standard stratifying diagnostic tests (laboratory assessment: morphology, blood chemistry including ALT, AST, eGFR, creatinine, sodium, potassium, coagulation, urine analysis including pH, blood, protein, leukocytes, glucose, urobilinogen, bilirubin, ketones, nitrites, specific gravity, vital signs (body temperature, systolic and diastolic blood pressure, and pulse rate), ECG, cardiac function test, imaging test: CT/MRI scan).
  3. Patients with GD2 expression will be randomized in proportions (2:1) to the experimental (D) and control groups (S). The cohort D will consist of 16 subjects, the cohort S 8 subjects. The exploratory cohort D will receive the experimental regimen in 3-week cycles consisting of irinotecan given intravenously (iv) 50 mg/m2 after oral temozolomide 100 mg/m2 on days 1-5 and naxitamab administered iv 2.25 mg/kg/day over 30 - 60 minutes, days 2, 4, 8 and 10 (up to 150 mg/day; total 9 mg/kg per cycle), and GM-CSF 250 mg/m2/day subcutaneously, days 6-10. Patients randomized to arm S will receive IT alone. Treatment cycles will be repeated every 21 days summary to 6 cycles or until disease progression, or subsequent relapsed, or occurrence of intolerable toxicity, or any event making impossible treatment continuation, or investigator's judgment, or withdrawal of consent. All activities are presented in Schedule of Assessments (SoA) at the end of the study synopsis.
  4. Patients will be recalculated according to the intent to treat (ITT) rule.
  5. The study will be conducted in accordance to GCP and after EC approval of the protocol.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
24

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • Poland
      • Wroclaw, Poland, 50-556
        • Not yet recruiting
        • Wroclaw Medical University
        • Contact:
        • Principal Investigator:
          • Marek Ussowicz, Prof.
    • Mazowian
      • Warsaw, Mazowian, Poland, 01-211
        • Recruiting
        • Mother and Child Institute
        • Contact:
        • Principal Investigator:
          • Anna Raciborska, Prof

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Child
  • Adult

Accepts Healthy Volunteers

No

Description

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

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Experimental - Naxitamab Arm
Treatment with naxitamab will be continued no longer than 6 cycles a year or until disease progression, patient consent, unacceptable toxicities, or study closure
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.
Other Names:
  • danyelza
No Intervention: Control Group - standard treatment
The control group - will receive only standard treatment.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Safety assessment of the addition of naxitamab to standard 3-week chemotherapy (CHT) in patients with refractory Ewing's sarcoma (ES)
Time Frame: up to 240 days
Safety will be assessed by number of serious adverse events (SAE), by the number of adverse events (AE), by medical examination with the analysis of recorded vital signs, laboratory abnormalities according to NCI CTCAE v5.0
up to 240 days

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Event-Free Survival (EFS )
Time Frame: 3 years
Will be measured from randomization to death, disease progression or recurrence, or secondary malignancy, whichever comes first
3 years
Progression-Free Survival (PFS)
Time Frame: 1 year
from randomization to progression of the disease
1 year
Overall Response Rate (ORR)
Time Frame: 126 days
Defined as the proportion of patients with a best overall response of complete response (CR) or partial response (PR),
126 days
Overall Survival (OS)
Time Frame: 3 years
Will be measured from randomization to subject's death
3 years

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Anna Raciborska

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Wroclaw Medical University

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Anna Raciborska, Prof., the Institue of Mother and Child

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
October 24, 2023

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
May 1, 2027

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
July 31, 2028

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
June 13, 2023

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 28, 2023

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
August 1, 2023

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
August 21, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 19, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
August 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • Butterfly (Alias Study Number)

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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