GD2 CAR T Cells in Diffuse Intrinsic Pontine Gliomas(DIPG) & Spinal Diffuse Midline Glioma(DMG)

Phase 1 Clinical Trial of Autologous GD2 Chimeric Antigen Receptor (CAR) T Cells (GD2CART) for Diffuse Intrinsic Pontine Gliomas (DIPG) and Spinal Diffuse Midline Glioma (DMG)

California Institute for Regenerative Medicine (CIRM), CureSearch, National Institutes of Health (NIH)

The primary purpose of this study is to test whether GD2-CAR T cells can be successfully made from immune cells collected from children and young adults with H3K27M-mutant diffuse intrinsic pontine glioma (DIPG) or spinal H3K27M-mutant diffuse midline glioma (DMG). H3K27Mmutant testing will occur as part of standard of care prior to enrollment.

Primary Objectives: Determine the feasibility of manufacturing autologous T cells transduced with 14g2a-CD8-BBz-iCasp9 retroviral vector expressing GD2 Chimeric Antigen Receptor (GD2CART) for administration in subjects with H3K27M+ diffuse intrinsic pontine glioma (DIPG) or subjects with spinal H3 K27M-mutant diffuse midline glioma (DMG) using a retroviral vector and dasatinib in the Miltenyi CliniMACS Prodigy® system. Assess the safety and identify the maximum tolerated dose (MTD) and/or recommended phase 2 dose (RP2D) of GD2CART in subjects with H3K27M+ DIPG administered after cyclophosphamide/fludarabine-based lymphodepletion regimen using the following dose escalation schedule: DL1: 1e6 transduced T cells/kg; DL2: 3e6 transduced T cells/kg; DL3: 10e6 transduced T cells/kg. Assess the safety of the MTD/RP2D of GD2CART in subjects with spinal H3K27M mutant DMG. Secondary Objectives: In a preliminary manner, assess clinical benefit of GD2CART at the RP2D in subjects with H3K27M DIPG or spinal H3 K27M-mutant DMG. If unacceptable toxicity occurs that is possibly, probably or likely related to GD2CART, assess the capacity for AP1903, a dimerizing agent, to mediate clearance of the genetically engineered cells and resolve toxicity.

Rolling-6 dose escalation design will test GD2-CAR T cells in subjects with H3K27M-mutant DIPG. GD2CART will be administered in escalating doses on Day 0 in hospitalized subjects with either DIPG or spinal DMG Intravenously Dose Level -1: 3x10^5 transduced T cells/kg(± 20%) Dose Level 1: 1x10^6 transduced T cells/kg (± 20%) Dose Level 2: 3x10^6 transduced T cells/kg (± 20%) Intracerebroventricularly, without conditioning lymphodepletion chemotherapy Dose Level -1: 10x10^6 transduced T cells (±20%) Dose Level 1: 30x10^6 transduced T cells (±20%) Dose Level 2: 50x10^6 transduced T cells (±20%) Dose Level 3: 100x10^6 transduced T cells (±20%) Intracerebroventricularly after administration of conditioning lymphodepletion chemotherapy regimen with cyclophosphamide and fludarabine Dose Level -1: 10x10^6 transduced T cells (±20%) Dose Level 1: 30x10^6 transduced T cells (±20%) Dose Level 2: 50x10^6 transduced T cells (±20%)

Autologous T-Cells transduced with retroviral vector (14g2a-CD8.BB.z.iCasp9) expressing GD2-chimeric antigen receptor

Rate of successful manufacture of GD2CART using a retroviral vector in the Miltenyi CliniMACS Prodigy system

Severity of dose limiting toxicities (DLTs) following chemotherapy and infusion of GD2CART cells, will be recorded and graded according to Common Terminology Criteria for Adverse Events (CTCAE) version 5.0 at each dose level tested in subjects with H3K27M-mutant DIPG following standard upfront radiation therapy.

Severity of dose limiting toxicities (DLTs) following chemotherapy and infusion of GD2CART cells will be recorded and graded according to Common Terminology Criteria for Adverse Events (CTCAE) version 5.0 in subjects with spinal H3K27M-mutant DMG following standard upfront radiation therapy

Radiographic Response will be evaluated using tumor response criteria: Complete Response (CR): disappearance on MR of all evaluable tumor and mass effect; stable or improving neurologic examination. If CSF was positive, it must be negative. Partial Response (PR): ≥ to 50% reduction in tumor size; stable or improving neurologic examination. Stable Disease (SD): at least stable and maintenance corticosteroid dose not increased, and MR/CT imaging meets neither PR nor PD Progressive Disease (PD): Progressive neurologic abnormalities or worsening neurologic status not explained by causes unrelated to tumor progression; OR a > 25% increase in the bi-dimensional measurement, OR the appearance of a new tumor lesion.

Time Frame: Day 28, 3 months, 6 months, 9 months and 12 months and 24 months post CAR T cell infusion.

OS is defined as the time from the start of the lymphodepleting chemotherapy preparative regimen to the date of death from any cause

Time Frame: Day 28, 3 months, 6 months, 9 months and 12 months and 24 months post CAR T cell infusion.

PFS is defined as the time from the start of the lymphodepleting chemotherapy preparative regimen to the date of radiographic progression or death from any cause.

Time Frame: Day 28, 3 months, 6 months, 9 months and 12 months and 24 months post CAR T cell infusion

PPS is measured for each subject with DIPG as OS minus PFS, and for each patient with recorded progression as OS minus Time to Progression (TTP)

Resolution of toxicity ≤ grade2, in the event unacceptable toxicity considered possibly, probably or definitely related to GD2CART cells within 72 hours

International patients are not currently eligible to enroll. Inclusion Criteria: Currently accepting US patients only Disease Status: Tissue diagnosis of H3K27M-mutated Diffuse Intrinsic Pontine Glioma (DIPG) with radiographically evident tumor restricted to the brainstem, OR Tissue diagnosis of H3K27M-mutated Diffuse Midline Glioma (DMG) of the spinal cord Age: Greater than or equal to 2 year of age and less than or equal to 50 years of age Prior Therapy: At least 6 weeks following completion of front line radiation therapy. At least 3 weeks post chemotherapy or 5 half-lives, whichever is shorter must have elapsed since any prior systemic therapy, except for systemic inhibitory/stimulatory immune checkpoint therapy, which requires 5 half-lives. Performance Status: Subjects > 16 years of age: Karnofsky ≥ 60% OR Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1; Subjects ≤ 16 years of age: Lansky scale ≥ 60% Normal Organ and Marrow Function (supportive care is allowed per institutional standards, i.e. filgrastim, transfusion) Absolute neutrophil count (ANC) ≥ 1,000/uL Platelet count ≥ 100,000/uL Absolute lymphocyte count ≥ 150/uL Hemoglobin ≥ 8 g/dL 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) ≤5 Years ---------------- 0.8mg/dL 5 < age ≤ 10 Years ----1.0mg/dL >10-18 Years -----------1.2mg/dL >18 Years -----------2.0mg/dL Serum Alanine aminotransferase( ALT)/Aspartate Aminotransferase (AST) ≤ 3.0 Upper limit of normal (ULN )(grade 1) 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 echocardiogram (ECHO), and no clinically significant ECG findings Baseline oxygen saturation > 92% on room air Pregnancy Test Females of childbearing potential must have a negative serum or urine pregnancy test (females who have undergone surgical sterilization are not considered to be of childbearing potential). Contraception 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 lymphodepletion regimen or for as long as GD2-CAR T cells are detectable in peripheral blood or cerebrospinal fluid (CSF). Ability to give informed consent. Pediatric subjects will be included in age appropriate discussion and verbal assent will be obtained for those > 7 years of age, when appropriate. Exclusion Criteria: Tumor involvement of cerebellar vermis or hemispheres (pontocerebellar peduncle involvement is allowed), thalamic lesions, or supratentorial lesions. Clinically significant swallowing dysfunction/dysphagia or prominent medullary dysfunction as judged by clinical assessment. Current systemic corticosteroid therapy Prior CAR therapy. Prior GD2-antibody therapy Ongoing use of dietary supplements, alternative therapies or extreme diets or any medication not approved by the investigators Uncontrolled fungal, bacterial, viral, or other infection. Previously diagnosed infection for which the patient continues to receive antimicrobial therapy is permitted if responding to treatment and clinically stable. Ongoing infection with HIV or hepatitis B (HBsAg positive) or hepatitis C virus (anti Hepatitis C Virus (HCV) positive). A history of hepatitis B or hepatitis C is permitted if the viral load is undetectable per quantitative polymerase chan reaction (PCR) and/or nucleic acid testing. Clinically significant systemic illness or medical condition (e.g. significant cardiac, pulmonary, hepatic or other organ dysfunction), that in the judgement of the principal investigator is likely to interfere with assessment of safety or efficacy of the investigational regimen and its requirements. 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. Known sensitivity or allergy to any agents/reagents used in this study. Primary immunodeficiency or history of autoimmune disease (e.g. Crohns, rheumatoid arthritis, systemic lupus) requiring systemic immunosuppression/systemic disease modifying agents within the last 2 years