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Cerebral ventricular fluid distribution of subcutaneous granulocyte-macrophage colony stimulating factor
L Helson1, S Braverman, S Rifkinson
1Department of Medicine, New York Medical College, Valhalla 10595.
Insights
High-dose thiotepa followed by granulocyte-macrophage colony-stimulating factor (GM-CSF) showed limited tumor response in a child with primitive neuroectodermal tumor. GM-CSF clearance was slower in tumor-affected ventricles, potentially impacting microglial anti-tumor activity.
Area of Science:
- Neuro-oncology
- Immunotherapy
- Pharmacokinetics
Background:
- Primitive neuroectodermal tumors (PNETs) are aggressive brain cancers.
- Hydrocephalus often complicates PNET treatment.
- Granulocyte-macrophage colony-stimulating factor (GM-CSF) is investigated for its potential role in cancer immunotherapy.
Observation:
- GM-CSF levels were measured in cerebrospinal fluid (CSF) from bilateral ventricles, one tumor-involved, after intravenous thiotepa and subcutaneous GM-CSF administration.
- Peak GM-CSF levels were observed simultaneously in both ventricles 11 hours post-injection.
- GM-CSF clearance was significantly prolonged in the tumor-involved ventricle (31 hours) compared to the tumor-free ventricle (15 hours).
Findings:
- The treatment regimen resulted in transient decreases in ventricular fluid white blood cells (WBC), protein, and lactate dehydrogenase (LDH).
- While microglia were detected, no direct anti-tumor activity was evident in biopsied tumor tissue.
- Tumor burden appeared to impede GM-CSF distribution and clearance within the ventricular system.
Implications:
- Altered GM-CSF pharmacokinetics in tumoral brain regions may limit its therapeutic efficacy.
- Further research is needed to understand the interaction between brain tumors, GM-CSF, and microglial responses.
- This study highlights potential challenges in delivering and clearing immunomodulatory agents in the presence of brain tumors.
Abstract:
After treating a child suffering from disseminated primitive neuroectodermal tumor and hydrocephalus with bilateral ventriculostomies, we administered intravenous high dose thiotepa followed by a single subcutaneous dose of GM-CSF 24 hours later. The appearance and clearance of GM-CSF were measured from both ventricles, one of which was surrounded by tumor. Peak levels of GM-CSF were recorded simultaneously in both ventricles 11 hours after injection. Complete clearance from injection required 15 hours and 31 hours for the tumor-free right ventricle and the tumor-involved left ventricular wall, respectively. Tumor response was ephemeral and limited to ventricular fluid WBC, protein and LDH decreases. Microglia were detected; however, there was no evidence of anti-tumor activity in biopsied tumor tissue. Tumored regions of the brain may have perturbation of GM-CSF distribution and clearance which may contribute to the lack of microglial activity.