Brain Tumor-Specific Immune Cells (IL13Ralpha2-CAR T Cells) for the Treatment of Leptomeningeal Glioblastoma, Ependymoma, or Medulloblastoma

Inclusion Criteria:

• Participant has verified leptomeningeal metastases

• Participant must have a Karnofsky performance status (KPS) >= 60

• Participant must have a life expectancy of >= 8 weeks

• If participant has a ventriculoperitoneal shunt, the valve must be programmable, andmust be able to tolerate their shunts being turned off for 48 hours

• The effects of IL13Ralpha2-CAR T cells on a developing fetus are unknown. For thisreason, women of child-bearing potential must have negative serum pregnancy test andagree to use a reliable form of birth control prior to study entry and for at leasttwo months following study treatment. Male research participants must agree to use areliable form of birth control and not donate sperm during the study and for atleast two months following study treatment

• Participant has a histologically confirmed IL13Ralpha2+ tumor expression byimmunohistochemistry (IHC) at the initial tumor presentation or recurrent disease (H-score >= 50)

• Participant must have the ability to understand and the willingness to sign awritten informed consent

• No known contraindications to leukapheresis, steroids, or tocilizumab

Exclusion Criteria:

• Research participant requires supplemental oxygen to keep saturation greater than 95% and the situation is not expected to resolve within 2 weeks

• Research participant requires dialysis

• Research participant has uncontrolled seizure activity and/or clinically evidentprogressive encephalopathy

• Failure of research participant to understand the basic elements of the protocoland/or the risks/benefits of participating in this phase 1 study. A legal guardianmay substitute for the research participant

• Participant is unwilling to stop treatment with chemotherapy or endocrine therapyand/or radiation one week prior and during the first 4 cycles of the IL13Ralpha2-CART cell study

• Shunted participants either have a non-programmable shunt valve, or cannot toleratetheir shunts being turned off for 48 hours

• Participant has a coagulopathy or bleeding disorder or cannot safely discontinueanticoagulation prior to placement of a Rickham reservoir

• Participant has a chronic or active viral infection of the central nervous system (CNS)

• Participant has any uncontrolled illness, including ongoing or active infection;participant has known active hepatitis B or C infection; participants with any signsor symptoms of active infection, positive blood cultures or radiological evidence ofinfections

• Participant is human immunodeficiency virus (HIV) seropositive based on testingperformed within 4 weeks of signing the main informed consent

• Participant has an autoimmune disease

• Participant has another active malignancy

• Participant is unable to undergo a brain magnetic resonance imaging (MRI)

• Participant is pregnant or breast feeding. Because there is an unknown but potentialrisk for adverse events in nursing infants secondary to treatment of the mother withIL13Ralpha2-CAR T cells, breastfeeding should be discontinued if the mother wants toparticipate in this study

• Prospective participants who, in the opinion of the Investigator, may not be able tocomply with all study procedures (including compliance issues related tofeasibility/logistics)