Convection-enhanced delivery of free gadolinium with the recombinant immunotoxin MR1-1.

Published

Journal Article

A major obstacle in glioblastoma (GBM) therapy is the restrictive nature of the blood-brain barrier (BBB). Convection-enhanced delivery (CED) is a novel method of drug administration which allows direct parenchymal infusion of therapeutics, bypassing the BBB. MR1-1 is a novel recombinant immunotoxin that targets the GBM tumor-specific antigen EGFRvIII and can be delivered via CED infusion. However, drug distribution via CED varies dramatically, which necessitates active monitoring. Gadolinium conjugated to diethylenetriamine penta-acetic acid (Gd-DTPA) is a commonly used MRI contrast agent which can be co-infused with therapies using CED and may be useful in monitoring infusion leak and early distribution. Forty immunocompetent rats were implanted with intracerebral cannulas that were connected to osmotic pumps and subsequently randomized into four groups that each received 0.2% human serum albumin (HSA) mixed with a different experimental infusion: (1) 25 ng/ml MR1-1; (2) 0.1 micromol/ml Gd-DTPA; (3) 25 ng/ml MR1-1 and 0.1 micromol/ml Gd-DTPA; (4) 250 ng/ml MR1-1 and 0.1 micromol/ml Gd-DTPA. The rats were monitored clinically for 6 weeks then necropsied and histologically assessed for CNS toxicity. All rats survived the entirety of the study without clinical or histological toxicity attributable to the study drugs. There was no statistically significant difference in weight change over time among groups (P > 0.999). MR1-1 co-infused with Gd-DTPA via CED is safe in the long-term setting in a pre-clinical animal model. Our data supports the use of Gd-DTPA, as a surrogate tracer, co-infused with MR1-1 for drug distribution monitoring in patients with GBM.

Full Text

Duke Authors

Cited Authors

  • Ding, D; Kanaly, CW; Bigner, DD; Cummings, TJ; Herndon, JE; Pastan, I; Raghavan, R; Sampson, JH

Published Date

  • May 2010

Published In

Volume / Issue

  • 98 / 1

Start / End Page

  • 1 - 7

PubMed ID

  • 19898744

Pubmed Central ID

  • 19898744

Electronic International Standard Serial Number (EISSN)

  • 1573-7373

Digital Object Identifier (DOI)

  • 10.1007/s11060-009-0046-7

Language

  • eng

Conference Location

  • United States