Convection-enhanced delivery of a hydrophilic nitrosourea ameliorates deficits and suppresses tumor growth in experimental spinal cord glioma models

Background Convection-enhanced delivery (CED) is a technique allowing local infusion of therapeutic agents into the central nervous system, circumventing the blood-brain or spinal cord barrier. Objective To evaluate the utility of nimustine hydrochloride (ACNU) CED in controlling tumor progression in an experimental spinal cord glioma model. Methods Toxicity studies were performed in 42 rats following the administration of 4 μl of ACNU CED into the mid-thoracic spinal cord at concentrations ranging from 0.1 to 10 mg/ml. Behavioral analyses and histological evaluations were performed to assess ACNU toxicity in the spinal cord. A survival study was performed in 32 rats following the implantation of 9 L cells into the T8 spinal cord. Seven days after the implantation, rats were assigned to four groups: ACNU CED (0.25 mg/ml; n = 8); ACNU intravenous (i.v.) (0.4 mg; n = 8); saline CED ( n = 8); saline i.v. ( n = 8). Hind limb movements were evaluated daily in all rats for 21 days. Tumor sizes were measured histologically. Results The maximum tolerated ACNU concentration was 0.25 mg/ml. Preservation of hind limb motor function and tumor growth suppression was observed in the ACNU CED (0.25 mg/ml) and ACNU i.v. groups. Antitumor effects were more prominent in the ACNU CED group especially in behavioral analyses ( P < 0.05; log-rank test). Conclusions ACNU CED had efficacy in controlling tumor growth and preserving neurological function in an experimental spinal cord tumor model. ACNU CED can be a viable treatment option for spinal cord high-grade glioma.