Sponsor: Crystal Mackall, MD (other)
Phase: 1
Start date: July 11, 2024
Planned enrollment: 41
B7-H3 CAR-T therapies are autologous or allogeneic chimeric antigen receptor T cells engineered to recognize B7-H3 (CD276), a checkpoint-like immunomodulatory molecule overexpressed across many solid tumors and associated with poor outcomes. Clinical-stage programs include TX103 for recurrent glioblastoma (rGBM) and a fourth‑generation construct 4SCAR‑276 being studied in B7‑H3–positive solid tumors. Interim human data have been presented for TX103 in rGBM; other programs (e.g., 4SCAR‑276) remain in early-phase evaluation without published response outcomes to date. (aacrjournals.org)
TX103 (autologous B7‑H3 CAR‑T; rGBM) - Study: Phase 1, single‑arm, dose‑escalation with intracavitary and/or intraventricular administration via Ommaya; NCT05241392. Interim ASCO 2024 abstract reported 13 treated patients between March 2022 and January 2024. (ascopubs.org) - Outcomes (interim): Among six patients from dose levels 1–2 evaluable for 12‑month survival as of January 2024, 12‑month OS was 83.3% (95% CI 58.3–100); median OS 20.3 months (95% CI 20.3–not reached). In dose level 2, two of three patients achieved partial and complete responses, respectively. CSF cytokines (e.g., IL‑6, IFN‑γ) and CAR transgene copies increased post‑infusion, with minimal peripheral changes. (ascopubs.org)
Allogeneic B7‑H3 CAR‑T in recurrent high‑grade glioma (for context; different product) - MT027 UCAR‑T IIT (ChiCTR2100047968): ASCO 2023/2024 abstracts reported favorable tolerability with no grade ≥3 toxicities; 12‑month OS 85.7% (95% CI 48.7–97.4) in one analysis; PK/PD showed CSF persistence and cytokine increases. These are single‑center, early‑phase data. (ascopubs.org)
4SCAR‑276 (B7‑H3 CAR‑T; fourth‑generation) - Multicenter Phase I/II trial in B7‑H3–positive solid tumors (NCT04432649) is listed; as of the latest registry snapshots, no results are posted. (cdek.pharmacy.purdue.edu)
TX103 (NCT05241392; interim)
- No dose‑limiting toxicities or treatment‑related deaths reported among 13 patients.
- Treatment‑related adverse events included cytokine release syndrome, increased intracranial pressure, headache, seizures, decreased consciousness, vomiting, and fever; most were grade 1–2. Three grade‑3 events occurred (increased intracranial pressure at dose level 2; seizure and decreased level of consciousness at dose level 3). (ascopubs.org)
Allogeneic B7‑H3 UCAR‑T (context) - Early reports noted no grade ≥3 toxicities, with most common events being fever and headache; no CRS/ICANS/GvHD observed in the presented dataset. (ascopubs.org)
Notes: Published evidence to date is primarily from conference abstracts and trial registries; peer‑reviewed, full clinical manuscripts for these specific products were not identified as of October 7, 2025.
Last updated: Oct 2025
Goal: Evaluate feasibility of manufacturing autologous B7-H3 CAR T cells and establish safety, MTD/RP2D, and preliminary antitumor activity of a single intravenous dose in pediatric and young adult patients with relapsed/refractory B7-H3–expressing solid tumors.
Patients: Children and young adults aged 2–30 years (first three treated: 12–30) with histologically confirmed relapsed/refractory solid tumors including neuroblastoma, soft tissue sarcoma, osteosarcoma, Ewing sarcoma, and Wilms tumor after standard therapies. Measurable or evaluable disease required during dose escalation; measurable disease required in expansion (neuroblastoma may be MIBG-positive only). Archival tissue or willingness to biopsy for B7-H3 expression analysis, though positivity is not required. Adequate performance status and organ function; key exclusions include uncontrolled infection, active HIV/hepatitis with viremia, significant recent cardiac disease, untreated brain metastases, need for systemic immunosuppression, pregnancy, and inability to comply with study procedures.
Design: Phase 1, single-arm, open-label, standard 3+3 dose-escalation with planned expansion; allocation not applicable. Primary focus on manufacturing feasibility and safety/MTD of a single IV CAR-T infusion following lymphodepletion.
Treatments: All participants receive lymphodepleting chemotherapy with fludarabine 30 mg/m2/day IV on days −5 to −2 and cyclophosphamide 500 mg/m2/day IV on days −5 to −3, followed by a single IV infusion of autologous B7-H3CART on day 0. B7-H3CART is an autologous T-cell product engineered with a lentiviral vector (Ef1a-CAR276) to express a CAR targeting CD276 (B7-H3), a checkpoint-related protein broadly overexpressed on pediatric and adult solid tumors with limited normal tissue expression. Early clinical experience with B7-H3 CAR-T in other programs, particularly in pediatric CNS tumors using locoregional delivery, has shown manageable safety and signals of activity, while IV administration in solid tumors remains investigational and is being defined in this study.
Outcomes: Primary: feasibility of manufacturing B7-H3CART with the specified platform; safety and determination of MTD/RP2D for single-dose IV B7-H3CART. Secondary: preliminary clinical response and additional safety characterization at the MTD/RP2D. Time frame for primary and secondary endpoints is up to 2 years.
Burden on patient: High. Participants undergo leukapheresis for autologous T-cell manufacturing, pre-infusion screening and baseline assessments, lymphodepleting chemotherapy requiring multiple consecutive infusion days, and a day-0 CAR-T infusion with intensive early safety monitoring for cytokine release syndrome, neurotoxicity, cytopenias, and infections. Archival tumor tissue must be available or a new biopsy may be required for B7-H3 expression analysis. Expect frequent clinic visits, laboratory monitoring, and imaging to assess response over 2 years, along with potential hospitalization around infusion. Travel burden may be substantial given the specialized center and close follow-up schedule typical for first-in-human cellular therapy trials.
Last updated: Oct 2025
Inclusion Criteria:
1. Histologically confirmed malignant solid tumor (including neuroblastoma, soft tissue sarcoma, osteosarcoma, Ewing Sarcoma, and Wilms tumor) with evidence of incurable disease and tumor recurrence/progression after all available curative standard therapies.
1. Subjects with neuroblastoma must have received or be intolerant to anti-GD2 antibody therapy.
2. Subjects with Wilm's tumor must have received or be intolerant to ifosfamide or cyclophosphamide plus etoposide therapy or alternative salvage regimen.
3. Subjects with embryonal rhabdomyosarcoma must have received or be intolerant to Adriamycin-based therapy.
4. Subjects with surgically resected pulmonary osteosarcoma in first recurrence must have received surgical resection of metastatic nodules.
2. Subjects during dose escalation must have evaluable or measurable disease. Subjects during dose expansion must have measurable disease, except neuroblastoma which may have MIBG positive disease only.
3. B7-H3 positive expression on malignant cells is NOT required but archival tissue must be available, or the subject must be willing to undergo tissue biopsy for expression analysis.
4. Age: Must be ≥ 2 and ≤ 30 years of age.
\* For the first three subjects treated with B7-H3CART, must be ≥ 12 and ≤ 30 years of age.
5. Performance Status: Patients \> 16 years of age must have Karnofsky ≥ 50%. Patients ≤ 16 years of age must have Lansky scale ≥ 50%; or ECOG performance status ≤ 2.
6. Prior Therapy
1. No limit to the number of prior therapies.
2. Prior Therapy Wash-out: At least 2 weeks or 5 half-lives, whichever is shorter, must have elapsed since any prior systemic therapy at the time the subject is planned for leukapheresis, except for systemic inhibitory/stimulatory immune checkpoint therapy, which requires 5 half-lives. Radiation therapy must have been completed at least 3 weeks prior to enrollment, with the exception that there is no time restriction if the subject has measurable/evaluable disease outside the radiation port or the site of radiation has documented progression.
7. Normal Organ and Marrow Function (supportive care is allowed per institutional standards, i.e. filgrastim, transfusion)
* ANC ≥ 750/uL\*
* Platelet count ≥ 75,000/uL\*
* Absolute lymphocyte count ≥ 150/uL\*
* Adequate renal, hepatic, pulmonary and cardiac function defined as:
* Creatinine within institutional norms for age(i.e. ≤ 2 mg/dL in adults or according to table below in children \<18 years) OR creatinine clearance (as estimated by Cockcroft Gault Equation) ≥ 60 mL/min
Age (Years) Maximum \& Serum Creatinine (mg/dL):
Age (Years): ≤5 \& Maximum Serum Creatinine (mg/dL): 0.8 Age (Years): 5 \< age ≤ 10 Maximum Serum Creatinine (mg/dL): 1.0 Age (Years): \>10-18 Maximum Serum Creatinine (mg/dL): 1.2 Age (Years): \> 18 Maximum Serum Creatinine (mg/dL): 2.0
* Serum ALT/AST ≤ 2.5x ULN (unless elevated ALT/AST is associated with disease involvement of the liver, in which case this criterion will be waived and not disqualify a patient).
* Total bilirubin ≤ 1.5 mg/dl, except in subjects with Gilbert's syndrome.
* Cardiac ejection fraction ≥ 45%, no evidence of physiologically significant pericardial effusion as determined by an ECHO,
* No clinically significant ECG findings
* No clinically significant pleural effusion
* Baseline oxygen saturation \> 92% on room air
* if cytopenias are not judged by the investigator to be due to underlying disease (i.e. potentially reversible with anti-neoplastic therapy); A subject will not be excluded because of pancytopenia ≥ Grade 3 if it is due to disease, based on the results of bone marrow studies.
8. Females of childbearing potential must have a negative serum or urine pregnancy test (females who have undergone surgical sterilization or who have been postmenopausal for at least 2 years are not considered to be of childbearing potential).
9. Subjects of child-bearing or child-fathering potential must be willing to practice birth control from the time of enrollment on this study and for four (4) months after receiving the preparative regimen or for as long as CART cells are detectable in peripheral blood.
10. Must provide informed consent. For subjects \<18 years old, or adults with limited decision-making capacity, their legal authorized representative (LAR) (i.e. parent or guardian) must give informed consent. Pediatric subjects will be included in age appropriate discussion and assent will be obtained for those \> 7 years of age, when appropriate. If a minor becomes of age during participation of this study, he/she will be asked to reconsent as an adult.
Exclusion Criteria:
1. Receiving any other current investigational agents.
2. History of other malignancy, except non-melanoma skin cancer or carcinoma in situ (e.g. cervix, bladder, breast), unless disease free for at least 3 years.
3. Presence of untreated brain metastases will be excluded. Subjects with previous CNS tumor involvement that has been treated and is stable for at least 3 months following completion of therapy are permitted. Patients who are clinically stable as evidenced by no requirements for corticosteroids, no evolving neurologic deficits, and no progression of residual brain abnormalities without specific therapy, are permitted.
4. Presence of fungal, bacterial, viral, or other infection that is uncontrolled. Simple UTI and uncomplicated bacterial pharyngitis are permitted if responding to active treatment.
5. Ongoing infection with HIV or hepatitis B (HBsAg positive) or hepatitis C virus (anti HCV positive) as the immunosuppression contained in this study will pose unacceptable risk. A history of hepatitis B or hepatitis C is permitted if the viral load is undetectable per quantitative PCR and/or nucleic acid testing.
6. History of myocardial infarction, cardiac angioplasty or stenting, unstable angina, or other clinically significant cardiac disease within 12 months of enrollment.
7. Any medical condition that in the judgement of the sponsor investigator is likely to interfere with assessment of safety or efficacy of study treatment.
8. History of severe immediate hypersensitivity reaction to any of the agents used in this study.
9. Pregnant females are excluded from this study because the effects of autologous B7-H3CART on the developing human fetus are unknown and because the chemotherapy agents used in this trial (cyclophosphamide and fludarabine) are category D agents with the potential for teratogenic or abortifacient effects. Additionally, because there is an unknown but potential risk for adverse events (AEs) in nursing infants secondary to treatment of the mother with cyclophosphamide/fludarabine, breastfeeding should be discontinued if the mother is treated with cyclophosphamide/fludarabine. These potential risks may also apply to other agents used in this study.
10. Primary immunodeficiency or history of systemic autoimmune disease (e.g., Crohns, rheumatoid arthritis, systemic lupus) requiring systemic immunosuppression/systemic disease modifying agents within the last 2 years.
11. Patients who require systemic corticosteroid or other immunosuppressive therapy. (A one-week washout from systemic corticosteroid or other immunosuppressive therapy is permitted.) Use of physiologic doses of corticosteroids (up to 3 mg/m2/day prednisone equivalent) are permitted. Use of topical, ocular, intra-articular, intra-nasal, or inhaled corticosteroids are permitted.
12. In the investigator's judgment, the subject is unlikely to complete all protocol required study visits or procedures, including follow up visits, or comply with the study requirements for participation.
Palo Alto, California, 94304, United States
[email protected] / 650-497-8953
Status: Recruiting