Pediatric OsteosarcomaPhase 2NCT07428993
Evaluating Efficacy of B7-H3-CAR T Cells Administered at the End of Upfront Map Chemotherapy in Patients With Newly Diagnosed High-Risk Osteosarcoma
A Phase 2 study testing Cyclophosphamide, Fludarabine and Mesna in people with Pediatric Osteosarcoma, run by St. Jude Children's Research Hospital at 1 site in United States.
Trial summary
The purpose of this study is to assess the safety, feasibility, and effectiveness of a consolidative B7-H3 CAR T cell therapy in patients with newly diagnosed high-risk osteosarcoma who have undergone upfront standard chemotherapy. Read more about this study
- Who is it for?
- Ages Up to 21 years
- Conditions the study is for
- Pediatric Osteosarcoma
- What is being tested?
- Cyclophosphamide, Fludarabine and Mesna
- Type of treatment
- Injection or infusion, Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 41 participants
- Where
- 1 siteUnited States
- Study dates
- Sep 2026to Dec 2035
- Phase
- Phase 2
- 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 Up to 21 years
- All sexes
- No healthy volunteers
- Child, Adult
Who may be able to join
- Participant and/or legally authorized representative has signed the Informed Consent Form for this study
- Prior cancer therapy:
- Regimen A only: Completed all planned cycles of consolidation therapy between 14-28 days prior.
- Regimen B only: has completed all planned cycles of consolidation chemotherapy at least 14 days prior and if clinically indicated, participant has undergone pulmonary metastasectomy. They must have recovered from any surgical complications with no ongoing sequelae of category 2 or higher by the Clavien-Dindo classification system and less than 6 weeks must have passed from time of pulmonary metastasectomy.
- No evidence of progressive disease since enrolled on study
- Lansky performance status score of ≥ 50 for participants <16 years of age or Karnofsky score ≥ 50 for participants ≥ 16 years. Participants who are unable to walk because of paralysis, but who are up in a wheelchair, will be considered ambulatory for purposes of assessing performance status
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- Adequate organ function as indicated by:
- Renal: Serum creatinine ≤ 1.5 X the upper limit of normal (ULN) based on enrollment eligibility table.
- Hepatic: Total bilirubin ≤ 3 times ULN for age OR conjugated bilirubin ≤ 2 mg/dL AND ALT (SGPT) ≤ 5 times ULN
- Cardiac: Shortening fraction ≥ 28% OR ejection fraction ≥ 50% as measured by echocardiogram
- Respiratory: Oxygen saturation ≥ 90% on room air without supplemental oxygen or mechanical ventilation
- Laboratory values meet the following criteria:
- Absolute Neutrophil Count (ANC) ≥ 750 cells/uL
- Platelet Count of ≥ 75,000 (can be transfused)
- Hemoglobin ≥ 7 g/dL (can be transfused)
- Participant is ≥ 7 days from receiving supra-physiologic dosing of systemic (IV or PO) corticosteroids. Glucocorticosteroid physiologic replacement therapy for management of adrenal insufficiency is allowed.
- Participant and/or legally authorized representative has signed the Informed Consent Form for the treatment phase of this study.
Who cannot join
- Major surgical adverse event related to the primary tumor local control defined as Clavien-Dindo category 3 requiring ongoing wound care.
- Evidence of clinically significant encephalopathy/new focal neurologic deficits.
- Presence of active severe infection, defined as:
- positive blood culture within 48 hours of enrollment, OR
- fever above 38.2° C, AND clinical signs of infection within 48 hours of enrollment
- Participant has received prior disease-directed therapy other than 1st line therapy with methotrexate, an anthracycline, and a platinum and local control surgery
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- Regimen B only - okay to have undergone initial pulmonary metastasectomy
- Pregnant or breastfeeding
- Presence of any condition that, in the opinion of the investigator, would prohibit the participant from undergoing treatment under this protocol
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
St. Jude Children's Research Hospital
Memphis, Tennessee, 38105-2794
Julie Park, MD, 888-226-4343, referralinfo@stjude.org
Julie Park, MD
About this study
Official title: A Phase II Study Evaluating Efficacy of B7-H3-CAR T Cells Administered at the End of Upfront Map Chemotherapy in Patients With Newly Diagnosed High-Risk Osteosarcoma
The purpose of this study is to assess the safety, feasibility, and effectiveness of a consolidative B7-H3 CAR T cell therapy in patients with newly diagnosed high-risk osteosarcoma who have undergone upfront standard chemotherapy.
Primary Objectives:
Read more
- To evaluate 1-year RFS from the time of SJCARB7H3-41BBL infusion for patients with newly diagnosed metastatic osteosarcoma who received standard chemotherapy.
Secondary Objectives:
- To evaluate the OS from time of SJCARB7H3-41BBL infusion for patients with newly diagnosed metastatic osteosarcoma who received standard chemotherapy.
- To evaluate the feasibility of delivering SJCARB7H3-41BBL at the end of standard therapy in patients with newly diagnosed metastatic osteosarcoma.
- To describe the safety of autologous SJCARB7H3-41BBL therapy when delivered at the end of standard therapy in patients with newly diagnosed metastatic osteosarcoma.
Read the detailed description
This is a phase 2 study of SJCARB7H3-41BBL for participants with newly diagnosed high-risk metastatic osteosarcoma who received standard chemotherapy.
All participants will receive standard chemotherapy (for example methotrexate, anthracycline, platinum), local control surgery, and pulmonary metastasectomy if applicable, and this is not considered part of protocol therapy. Participants will undergo apheresis prior to standard local control surgery (about 12 weeks after diagnosis) for SJCARB7H3-41BBL manufacture and then resume standard consolidation therapy. A safety run will initiate with Regimen A. For Regimen A, eligible participants with available SJCARB7H3-41BB product will receive lymphodepletion chemotherapy 14-28 days after the completion of standard chemotherapy (31 weeks after diagnosis), followed by SJCARB7H3-41BB infusion. If Regimen A is not cleared, then Regimen B will be evaluated, where lymphodepletion and SJCARB7H3-41BB infusion occur post pulmonary metastasectomy. Following successful clearance of either regimen A or, if necessary, regimen B, then the efficacy cohort will be initiated. Participants will be followed with serial disease evaluations for 2 years from SJCARB7H3-41BB infusion prior to transfer to our institutional long-term follow-up (LTFU) protocol. The total duration from completion of standard therapy, including experimental therapy and follow-up on 3CAR4OS, is approximately 2 years.
- Conditions
- Pediatric Osteosarcoma
- Being tested
- Cyclophosphamide, Fludarabine, Mesna, Apheresis, SJCARB7H3_41BBL infusion
- Keywords
- Osteosarcoma
- Medical subject headings
- Osteosarcoma
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
CyclophosphamideDrug
IV
FludarabineDrug
IV
MesnaDrug
IV prior to and again at 3, 6, and 9 hours following each dose of cyclophosphamide.
ApheresisProcedure or surgery
IV collection
SJCARB7H3_41BBL infusionProcedure or surgery
1X107 CAR+ T cells/kg
| Study group | Role | What they receive |
|---|---|---|
| 3CAR4OS Treatment | Experimental | All patients will receive standard of care chemotherapy, which is not considered part of protocol therapy. Eligible patients will undergo apheresis prior to standard local control surgery for CAR T cell manufacture and then resume standard therapy. In the absence of progressive disease, eligible patients with available SJCARB7H3-41BBL product will receive lymphodepletion chemotherapy (fludarabine/cyclophosphamide) after the completion of standard chemotherapy, followed by SJCARB7H3-41BBL infusion. Pulmonary metastasectomy will be performed as indicated according to the standard of care and will be timed after (Regimen A) or before (Regimen B) lymphodepletion and SJCARB7H3-41BBL infusion. Following successful clearance of either regimen A or, if necessary, regimen B, the efficacy cohort will be initiated. Receives: Drug: Cyclophosphamide; Drug: Fludarabine; Drug: Mesna; Procedure: Apheresis; Procedure: SJCARB7H3_41BBL infusion |
What is being measured
The primary outcome is the main question the study is designed to answer.
Event-free survival (EFS), defined as time from SJCARB7H3-41BBL infusion to disease relapse, progressive disease, new systemic therapy, secondary malignancy or death
Event-free participants will be censored at the time of last follow-up. This analysis will report the Kaplan-Meier (KM) curve, along with the 12-month EFS estimate and its 80% confidence interval using the arcsine-square root transformation. Evaluable participants are those who complete standard chemotherapy, receive SJCARB7H3-41BBL and are treated on the regimen used for the Efficacy phase.
Measured: Time from SJCARB7H3-41BBL infusion to time of first event, followed up to 24-months post-infusion
Secondary outcomes (3)
Overall survival (OS), defined as time from SJCARB7H3-41BBL cell infusion to all-cause mortality.
Event-free participants will be censored at the time of last follow-up. OS will be reported similarly to the EFS endpoint on the same participant subset.
Measured: Time from SJCARB7H3-41BBL infusion to time of death from any cause, followed up to 24-months post-infusion
Number of participants experiencing protocol-specified regimen-related toxicities.
This outcome measure will be descriptively summarized for the overall participant group and by regimen (if more than 1 regimen is evaluated) for each regimen-related toxicity. Evaluable participants include those who receive SJCARB7H3_41BBL and remain on protocol therapy through at least 28 days post-infusion or experience a related unacceptable toxicity.
Measured: Time from SJCARB7H3-41BBL infusion up to 28 days post-infusion.
Number of participants with successful manufacture of SJCARB7H3-41BBL cells of sufficient dose and planned product administration
This outcome measure will be descriptively summarized for the overall participant group and by regimen (if more than 1 regimen is evaluated) for participants who undergo apheresis and remain on protocol therapy through the end of standard therapy.
Measured: Time of SJCARB7H3-41BBL infusion
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted24 Feb 2026
- Study startSep 2026 (estimated)
- Primary completionDec 2034 (estimated)
- Study completionDec 2035 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Pediatric OsteosarcomaStudies of the same condition, open and under way.
- More trials run by St. Jude Children's Research HospitalThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 41 participants (estimated)
Sponsor and investigators
- Lead sponsor
- St. Jude Children's Research Hospital
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Julie Park, MD, Principal investigator, St. Jude Children's Research Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07428993
- Sponsor's protocol ID
- 3CAR4OS
- Status last verified
- Aug 2026
- First submitted
- 5 Feb 2026
- Last updated
- 1 Sep 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- Yes: Individual participant de-identified datasets containing the variables analyzed in the published article will be made available (related to the study primary or secondary objectives contained in the publication). Supporting documents such as the protocol, statistical analyses plan, and informed consent are available through the CTG website for the specific study. Data used to generate the published article will be made available at the time of article publication. Investigators who seek access to individual level de-identified data will contact the computing team in the Department of Biostatistics (ClinTrialDataRequest@stjude.org) who will respond to the data request.
Study at a glance
From the registry record, last updated by the sponsor on 1 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Phase II Study Evaluating Efficacy of B7-H3-CAR T Cells Administered at the End of Upfront Map Chemotherapy in Patients With Newly Diagnosed High-Risk Osteosarcoma
- ClinicalTrials.gov ID
- NCT07428993
- Acronym / sponsor ID
- 3CAR4OS
- Conditions
- Pediatric Osteosarcoma
- Keywords
- Osteosarcoma
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 41 participants (estimated)
- Lead sponsor
- St. Jude Children's Research HospitalUniversity, hospital or other
- Study start
- Sep 2026 (estimated)
- Primary completion
- Dec 2034 (estimated)
- Study completion
- Dec 2035 (estimated)
- First posted
- 24 Feb 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The purpose of this study is to assess the safety, feasibility, and effectiveness of a consolidative B7-H3 CAR T cell therapy in patients with newly diagnosed high-risk osteosarcoma who have undergone upfront standard chemotherapy.
Primary Objectives:
- To evaluate 1-year RFS from the time of SJCARB7H3-41BBL infusion for patients with newly diagnosed metastatic osteosarcoma who received standard chemotherapy.
Secondary Objectives:
- To evaluate the OS from time of SJCARB7H3-41BBL infusion for patients with newly diagnosed metastatic osteosarcoma who received standard chemotherapy.
- To evaluate the feasibility of delivering SJCARB7H3-41BBL at the end of standard therapy in patients with newly diagnosed metastatic osteosarcoma.
- To describe the safety of autologous SJCARB7H3-41BBL therapy when delivered at the end of standard therapy in patients with newly diagnosed metastatic osteosarcoma.
Detailed description
This is a phase 2 study of SJCARB7H3-41BBL for participants with newly diagnosed high-risk metastatic osteosarcoma who received standard chemotherapy.
All participants will receive standard chemotherapy (for example methotrexate, anthracycline, platinum), local control surgery, and pulmonary metastasectomy if applicable, and this is not considered part of protocol therapy. Participants will undergo apheresis prior to standard local control surgery (about 12 weeks after diagnosis) for SJCARB7H3-41BBL manufacture and then resume standard consolidation therapy. A safety run will initiate with Regimen A. For Regimen A, eligible participants with available SJCARB7H3-41BB product will receive lymphodepletion chemotherapy 14-28 days after the completion of standard chemotherapy (31 weeks after diagnosis), followed by SJCARB7H3-41BB infusion. If Regimen A is not cleared, then Regimen B will be evaluated, where lymphodepletion and SJCARB7H3-41BB infusion occur post pulmonary metastasectomy. Following successful clearance of either regimen A or, if necessary, regimen B, then the efficacy cohort will be initiated. Participants will be followed with serial disease evaluations for 2 years from SJCARB7H3-41BB infusion prior to transfer to our institutional long-term follow-up (LTFU) protocol. The total duration from completion of standard therapy, including experimental therapy and follow-up on 3CAR4OS, is approximately 2 years.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| 3CAR4OS Treatment | Experimental | Drug: Cyclophosphamide, Drug: Fludarabine, Drug: Mesna, Procedure: Apheresis, Procedure: SJCARB7H3_41BBL infusionAll patients will receive standard of care chemotherapy, which is not considered part of protocol therapy. Eligible patients will undergo apheresis prior to standard local control surgery for CAR T cell manufacture and then resume standard therapy. In the absence of progressive disease, eligible patients with available SJCARB7H3-41BBL product will receive lymphodepletion chemotherapy (fludarabine/cyclophosphamide) after the completion of standard chemotherapy, followed by SJCARB7H3-41BBL infusion. Pulmonary metastasectomy will be performed as indicated according to the standard of care and will be timed after (Regimen A) or before (Regimen B) lymphodepletion and SJCARB7H3-41BBL infusion. Following successful clearance of either regimen A or, if necessary, regimen B, the efficacy cohort will be initiated. |
Who may qualify
- Ages
- Up to 21 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult
Key inclusion criteria (17 listed)
- Participant and/or legally authorized representative has signed the Informed Consent Form for this study
- Prior cancer therapy:
- No evidence of progressive disease since enrolled on study
- Lansky performance status score of ≥ 50 for participants <16 years of age or Karnofsky score ≥ 50 for participants ≥ 16 years. Participants who are unable to walk because of paralysis, but who are up in a wheelchair, will be considered ambulatory for purposes of assessing performance status
- Adequate organ function as indicated by:
Key exclusion criteria (9 listed)
- Major surgical adverse event related to the primary tumor local control defined as Clavien-Dindo category 3 requiring ongoing wound care.
- Evidence of clinically significant encephalopathy/new focal neurologic deficits.
- Presence of active severe infection, defined as:
- Participant has received prior disease-directed therapy other than 1st line therapy with methotrexate, an anthracycline, and a platinum and local control surgery
- Pregnant or breastfeeding
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| CyclophosphamideIV | Drug | 3CAR4OS Treatment |
| FludarabineIV | Drug | 3CAR4OS Treatment |
| MesnaIV prior to and again at 3, 6, and 9 hours following each dose of cyclophosphamide. | Drug | 3CAR4OS Treatment |
| ApheresisIV collection | Procedure or surgery | 3CAR4OS Treatment |
| SJCARB7H3_41BBL infusion1X107 CAR+ T cells/kg | Procedure or surgery | 3CAR4OS Treatment |
Primary outcome
Event-free survival (EFS), defined as time from SJCARB7H3-41BBL infusion to disease relapse, progressive disease, new systemic therapy, secondary malignancy or death
Time frame: Time from SJCARB7H3-41BBL infusion to time of first event, followed up to 24-months post-infusion
Event-free participants will be censored at the time of last follow-up. This analysis will report the Kaplan-Meier (KM) curve, along with the 12-month EFS estimate and its 80% confidence interval using the arcsine-square root transformation. Evaluable participants are those who complete standard chemotherapy, receive SJCARB7H3-41BBL and are treated on the regimen used for the Efficacy phase.
3 secondary outcomes
Overall survival (OS), defined as time from SJCARB7H3-41BBL cell infusion to all-cause mortality.
Time frame: Time from SJCARB7H3-41BBL infusion to time of death from any cause, followed up to 24-months post-infusion
Number of participants experiencing protocol-specified regimen-related toxicities.
Time frame: Time from SJCARB7H3-41BBL infusion up to 28 days post-infusion.
Number of participants with successful manufacture of SJCARB7H3-41BBL cells of sufficient dose and planned product administration
Time frame: Time of SJCARB7H3-41BBL infusion
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 1 Sep 2026.
- St. Jude Children's Research HospitalLink provided by the sponsor.
- Clinical Trials Open at St. JudeLink provided by the sponsor.
- Individual participant dataSharing planned: Yes. Individual participant de-identified datasets containing the variables analyzed in the published article will be made available (related to the study primary or secondary objectives contained in the publication). Supporting documents such as the protocol, statistical analyses plan, and informed consent are available through the CTG website for the specific study. Data used to generate the published article will be made available at the time of article publication. Investigators who seek access to individual level de-identified data will contact the computing team in the Department of Biostatistics (ClinTrialDataRequest@stjude.org) who will respond to the data request.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Julie Park, MD principal investigator
St. Jude Children's Research Hospital
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Cyclophosphamide, Fludarabine and Mesna in people with Pediatric Osteosarcoma, run by St. Jude Children's Research Hospital 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 17 inclusion and 9 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 1 Sep 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?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
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 Julie Park, MD (888-226-4343, referralinfo@stjude.org), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Event-free survival (EFS), defined as time from SJCARB7H3-41BBL infusion to disease relapse, progressive disease, new systemic therapy, secondary malignancy or death (time frame: Time from SJCARB7H3-41BBL infusion to time of first event, followed up to 24-months post-infusion). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
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 1 Sep 2026.