Retrospective Review of Intra-Cerebrospinal Fluid (CSF) Drug Delivery in CNS Malignancies: Safety, Clinical Efficacy and Pharmacokinetic Profiles of Intracerebroventricular (ICV), Lumbar Intrathecal (LIT), and Intra-Cisterna Magna (ICM) Injections

Background/Objectives: The blood-brain barrier and blood-CSF barrier limit the uptake of CNS-targeted therapeutics, warranting utilization of intra-cerebrospinal fluid (CSF) drug delivery. Here we review and compare the safety and distribution of different intra-CSF delivery methods reported in clinical literature. Methods: A retrospective literature review of three common CSF access methods was performed. A search consisting of clinical trials published on PubMed from 2000-2024 using the following search terms-intracerebroventricular/intraventricular/ICV, intrathecal/IT, intralumbar/lumbar puncture, cisterna magna/ICM/IT-CM, drug delivery, drug administration, and CSF-yielded 38 intracerebroventricular (ICV), 110 lumbar intrathecal (LIT), and six intra-cisterna magna (ICM) studies. Results: After final exclusion criteria were applied, there were 12 ICV, two LIT, and zero ICM publications remaining for analysis. ICV-specific safety was addressed in 11 ICV publications, with headache, nausea, and vomiting being among the most frequently mentioned procedure-associated adverse events (AEs). LIT-specific safety was provided in only one of the two studies, reporting mostly grade 1/2 AEs but also an instance of grade 4 myelosuppression. For clinical efficacy, progression-free survival (PFS), overall survival (OS), and disease progression rates were largely variable across studies. Pharmacokinetics were analyzed in four ICV studies. Conclusions: The safety profiles of both ICV and LIT injections are acceptable, showing mostly mild to moderate procedure-associated AEs and less common treatment-related AEs than systemically administered therapies. Additionally, ICV achieves therapeutic goals more consistently than the other intra-CSF delivery methods. To date, there are insufficient data to show dose-related response with intra-CSF delivery. Novel tools are being developed to improve upon intra-CSF delivery that will ideally lead to improved patient outcomes in the near future.