Objective: Convection-enhanced delivery (CED) holds tremendous potential for drug delivery to the brain. However, little is known about the volume of distribution achieved within human brain tissue or how target anatomy and catheter positioning influence drug distribution. The primary objective of this study was to quantitatively describe the distribution of a high molecular weight agent by CED relative to target anatomy and catheter position in patients with malignant gliomas.
Methods: Seven adult patients with recurrent malignant gliomas underwent intracerebral infusion of the tumor-targeted cytotoxin, cintredekin besudotox, concurrently with 123I-labeled human serum albumin. High-resolution single-photon emission computed tomographic images were obtained at 24 and 48 hours and were coregistered with magnetic resonance imaging scans. The distribution of 123I-labeled human serum albumin relative to target anatomy and catheter position was analyzed.
Results: Intracerebral CED infusions were well-tolerated and some resulted in a broad distribution of 123I-labeled human serum albumin, but target anatomy and catheter positioning had a significant influence on infusate distribution even within non-contrast-enhancing areas of brain. Intratumoral infusions were anisotropic and resulted in limited coverage of the enhancing tumor area and adjacent peritumoral regions.
Conclusions: CED has the potential to deliver high molecular weight agents into tumor-infiltrated brain parenchyma with volumes of distribution that are clinically relevant. Target tissue anatomy and catheter position are critical parameters in optimizing drug delivery.