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Human high-grade glioma cell lines (A1207, U-87MG, U-373MG, and F39) with high levels of epidermal growth factor receptor (EGF-R) expression were incubated for 2-48 h with 1 microCi/ml of the EGF-R-specific 125I-MAb 425 and measured for surface-bound, cytoplasmic, and nuclear radioactivity. The A1207 and U-373MG cell lines showed the highest surface-bound radioactivity with 215.9 +/- 8.7 nCi (30 h) and 287.8 +/- 23.2 nCi (24 h)/10(6) cells, respectively, whereas the U-87MG and the F39 cell lines bound significantly less antibody (48.8 +/- 5.4 nCi [48 h] and 31.1 +/- 0.7 nCi [24 h]). Surface-bound antibody was efficiently internalized into the cytoplasm. The U-373MG, U-87MG, and A1207 cell lines achieved 19.8% +/- 2.1 internalization of the surface-bound antibody in contrast to > 40% for the F39 cell line. Only the A1207 cell line showed significant nuclear radioactivity. There was no correlation between the reported EGF-R number and amount of antibody bound or internalized. We conclude that binding and uptake of the 125I-MAb 425 is specific for human glioma cells and shows saturation kinetics independent of receptor density.

The objective of this study was to assess the toxicity and potential efficacy of the adjuvant administration of an iodine 125 (125I)-labeled monoclonal antibody 425 for primary glioblastoma multiforme. From January 29, 1987, to October 1, 1993, 60 patients with a diagnosis of glioblastoma multiforme received an average of three intravenous or intraarterial injections of 125I-labeled antiepidermal growth factor receptor monoclonal antibody (1251425). All patients had biopsy or resection followed by postoperative radiation therapy. Patients were included who had either stereotactic irradiation or brachytherapy (5 patients), or who were not candidates for these treatments. Stratification was made by Karnofsky performance status (KPS) and age. Treatments were administered on an outpatient basis. The mean KPS was 78, and the total cumulative dose of 125I 425 was approximately 150 mCi. Among this entire group were 6 patients who received 10–80 mg of unlabeled “blocking” 425 to block binding sites on non-tumor cells prior to the second intravenous infusion of 125I 425. No patients were excluded from the statistical analysis. The median actuarial survival for all patients treated adjuvantly for glioblastoma multiforme was 13 months. Both age and KPS correlated positively with survival, as would be expected. The toxicity from the administration of repeated doses of 125I 425 was low. No patient had chronic toxicity attributed to the monoclonal antibody therapy. Acute toxicity was observed in 1 patient who received a single dose >60 mCi. We conclude that the repeated administration of 1251425 is safe and may have some benefit in the management of primary glioblastoma multiforme. This may be especially true for patients who do not qualify for other forms of more aggressive management. A prospective randomized trial should be performed. © 1995 Wiley-Liss, Inc.

Background. The monoclonal antibody anti-epidermal growth factor receptor (EGFr)antibody-425, against the epidermal growth factor receptor, has the potential to bind specifically to gliomas and not normal brain tissue. 1-3 A prospective study was conducted (1986-1988) to evaluate the use of Indium-111 ( 111 In)-labeled anti-EGFr-425 in the localization of gliomas before radioimmunotherapy with Iodine-125 ( 125 I)-labeled anti-EGFr-425. Methods. Twenty-eight patients with intracranial neoplasms were injected intravenously with an average dose of 2.2 mCi 111 In-labeled anti-EGFr-425

Twenty-five patients with primary presentation of malignant astrocytoma, astrocytoma with anaplastic foci, and glioblastoma multiforme were treated with surgical resection and definitive radiation therapy followed by intravenous or infra-arterial administration of Iodine-125 labeled monoclonal antibody-425, which binds specifically to human epidermal growth factor receptor. The patients presented with primary untreated disease, positive contrast enhanced computed tomography scans of the brain, and compatible clinical symptoms. In this Phase II clinical trial, the patients had surgical debulking or biopsy followed by definitively administered external beam radiation therapy and one or multiple doses (35 to 90 mCi per infusion) of radiolabeled antibody. The total cumulative doses ranged from 40 to 224 mCi. The administrations of the radiolabeled antibody were performed in most cases 4–6 weeks following completion of the primary surgery and radiation therapy. Ten patients had astrocytoma with anaplastic foci and 15 had glioblastoma multiforme. No significant life-threatening toxicities were observed during this trial. At 1 year 60% of the patients with astrocytoma with anaplastic foci or glioblastoma multiforme are alive. The median survival for both groups was 15.6 months.