EGFR806-specific CAR T Cell Locoregional Immunotherapy for EGFR-positive Recurrent or Refractory Pediatric CNS Tumors

• EGFR806-specific chimeric antigen receptor (CAR) T cell (Biological): Autologous CD4+ and CD8+ T cells lentivirally transduced to express an EGFR806 specific chimeric antigen receptor (CAR) and EGFRt given via indwelling central nervous system (CNS) catheter

Primary outcomes

• Safety: any adverse events associated with one or multiple EGFR806-specific CAR T cell product infusions will be assessed by CTCAE v5.0. [up to 6 months]: The type, frequency, severity, and duration of adverse events as a result of EGFR806-specific CAR T cell infusion will be summarized
• Feasibility: The number of successfully manufactured and infused EGFR806-specific CAR T cell product [28 days]: The proportion of products successfully manufactured and infused will be measured

Secondary outcomes

• CAR T cell distribution: The number of subjects with CAR T cell persistence in the cerebrospinal fluid (CSF) and peripheral blood as measured by flow cytometry [up to 6 months]: The trafficking of the EGFR806-specific CAR T cell product through the CSF by measuring remaining CAR T cells from a prior infusion at the time of each infusion and the trafficking of EGFR806-specific CAR T cells from the CSF into the peripheral blood will be evaluated.
• Expression of target epitope: assessment of whether EGFR expression changes in relapsed CNS tumors that were EGFR positive prior to treatment with CAR T cells via immunohistochemistry on resected tissue samples. [28 days]: The changes in EGFR expression at diagnosis and recurrence of central nervous system (CNS) tumors, if samples from multiple time points is available, will be investigated by evaluating pathology specimens from previous surgeries
• Disease response: Assessment of disease response of EGFR-expressing refractory or recurrent central nervous system (CNS) tumors to EGFR806 specific CAR T cell therapy delivered directly into the CNS by cytology and radiology criteria. [up to 6 months]: The response of recurrent or refractory central EGFR-expressing CNS tumors to EGFR806-specific CAR T cell therapy delivered directly into the CNS will be determined by evaluating CSF for tumor cells and by CNS imaging with MRIs.

Other outcomes

• Quantitative biomarker assessment of anti tumor CAR T cell functional activity [up to 6 months]: The presence of biomarkers of anti-tumor CAR T cell functional activity, such as cytokines, will be quantified via protein expression analysis in CSF. These findings will be correlated with safety determined by the occurrence of adverse events, and response by disease evaluations via CSF cytology and MRI imaging of the CNS.

Sex: All, ages: 1 Year to 26 Years

Inclusion Criteria:

1. Age ≥ 15 and ≤ 26 years
2. Histologically diagnosed EGFR positive Central Nervous System (CNS) tumor
3. Evidence of refractory or recurrent CNS disease for which there is no standard therapy
4. Able to tolerate apheresis or apheresis product available for use in manufacturing
5. CNS reservoir catheter, such as an Ommaya or Rickham catheter
6. Life expectancy ≥ 8 weeks
7. Lansky or Karnofsky score ≥ 60
8. If patient does not have previously obtained apheresis product, patient must have recovered from acute toxic effects of all prior chemotherapy, immunotherapy, and radiotherapy and discontinue the following prior to enrollment:

   1. ≥ 7 days post last chemotherapy/biologic therapy administration
   2. 3 half lives or 30 days, whichever is shorter post last dose of anti-tumor antibody therapy
   3. Must be at least 30 days from most recent cellular infusion
   4. All systemically administered corticosteroid treatment therapy must be stable or decreasing within 1 week prior to enrollment with maximum dexamethasone dose of 2.5 mg/m2/day. Corticosteroid physiologic replacement therapy is allowed.
9. Adequate organ function
10. Adequate laboratory values
11. Subjects of childbearing/fathering potential must agree to use highly effective contraception

Exclusion Criteria:

1. Diagnosis of classic diffuse intrinsic pontine glioma (DIPG)
2. Presence of ≥ Grade 3 cardiac dysfunction or symptomatic arrhythmia requiring intervention
3. Presence of primary immunodeficiency/bone marrow failure syndrome
4. Presence of clinical and/or radiographic evidence of impending herniation
5. Presence of active malignancy other than the primary CNS tumor under study
6. Presence of active severe infection
7. Receiving any anti-cancer agents or chemotherapy
8. Pregnant or breastfeeding
9. Subject and/or authorized legal representative unwilling to provide consent/assent for participation in the 15 year follow up period
10. Presence of any condition that, in the opinion of the investigator, would prohibit the patient from undergoing treatment under this protocol

• Juliane Gust, MD, PhD, Study chair, Seattle Children's Hospital