Study of Immunotoxin, MR1-1

Purpose of the study: Primary Objective: Determine the maximum tolerated dose (MTD) and dose limiting toxicity (DLT) of MR1-1KDEL when delivered intracerebrally by convection-enhanced delivery (CED) in patients with supratentorial malignant brain tumors. Secondary Objective: Document any radiographic responses associated with intracerebral CED of MR1-1KDEL. Hypothesis: The investigators believe that MR1-1KDEL will be an effective anti-tumor agent for patients with supratentorial malignant brain tumors when delivered by CED. Design \& procedures: This protocol is designed primarily to determine the MTD and DLT of a novel, tumor-specific immunotoxin, MR1-1KDEL. MR1-1KDEL will be delivered intracerebrally by CED using 2 intracerebral catheters with at least one catheter placed within the enhancing portion of the tumor. 124I-labeled albumin will be co-infused with gadolinium and PET and MRI images will be obtained at the conclusion of the infusion to monitor volume of drug distribution and leakage into the CSF space. Based on preclinical toxicity studies, the starting total drug dose will be 0.5μg (500ng) which represents 1/20th of the MTD in rats. The infusion flow rate will be fixed at 0.5 mL/h from each of two to four catheters. A total of 144 mLs of drug solution will be delivered over 72 hours. MR1-1KDEL dose escalation will be accomplished by increasing drug concentration allowing flow rate and infusion volume to remain unchanged. Drug dose will be doubled in successive cohorts so long as DLTs are not observed as follows: 25 ng/mL (2.4 μg)(starting dose); 50ng/mL (4.8μg); 100 ng/mL (9.6μg); 200ng/mL (19.2μg); 400 ng/mL (38.4μg); 800 ng/mL (76.8μg); and 1600 ng/mL (153.6μg). At least 3 patients will be enrolled in each cohort. All patients in a given cohort will be observed for at least two weeks following infusion of the study drug before patients in the next cohort are treated. If no patients in a given cohort experience a DLT, the dose will be escalated in the next cohort. If 1 out of 3 patients in a given cohort experience DLT, 3 additional patients will be entered in that cohort. If 2 patients develop a DLT in any cohort of 3 or 6 patients, the previous dose will be declared the MTD. Patients will be followed at 1, 3, 6, 9, 12 month intervals for toxicity and adverse events, radiographic response, and survival. Patients will be off study when progressive disease is documented. Risk/benefit assessment: This is an experimental study and unforeseeable or unexpected risks may be involved.