Arsenic Trioxide Combined With Chemotherapy for Relapsed SHH-Activated and/or TP53-Mutant Medulloblastoma

Other illness

• History of another malignancy for which the participant received chemotherapy and abdominal radiotherapy.

Lab values

• Severe progressive or persistent heart failure, defined as New York Heart Association (NYHA) class III or IV heart failure or a left ventricular ejection fraction (LVEF) \<50%.
• Severe progressive or persistent renal failure, defined as a glomerular filtration rate (GFR) \<30 mL/min/1.73 m² or serum creatinine \>5 mg/dL (442 μmol/L).
• Severe hepatic dysfunction, defined as aspartate aminotransferase (AST) or alanine aminotransferase (ALT) ≥5 times the age-appropriate upper limit of normal (ULN), or total serum bilirubin ≥3 times the age-appropriate ULN.

• Histologically confirmed SHH-activated medulloblastoma meeting at least one of the following conditions: Tumor recurrence demonstrated by imaging or cerebrospinal fluid examination after standard treatment consisting of surgery, radiotherapy, and chemotherapy; or Refractory medulloblastoma, defined as an increase in tumor size of more than 25% or the appearance of new lesions after two cycles of standard first-line chemotherapy.
• Medulloblastoma with a TP53 mutation identified by genetic testing of tumor tissue, including at least one of the following: A TP53 mutation present at initial diagnosis; A newly detected TP53 mutation during subsequent treatment in a patient with relapsed medulloblastoma; or A newly detected TP53 mutation during subsequent treatment in a patient with refractory medulloblastoma.
• Age ≥18 months and ≤18 years.
• Written informed consent obtained from the participant's legal guardian. Participants must meet either Inclusion Criterion 1 or Inclusion Criterion 2, in addition to Inclusion Criteria 3 and 4.