Radioiodinated (I-125) monoclonal antibody 425 in the treatment of high grade glioma patients: ten-year synopsis of a novel treatment

The present report is the follow-up of patients enrolled in a phase II clinical trial using I-MAb 425 as an adjuvant treatment for high grade gliomas. Patient median survivals support published data from an earlier preliminary report. From January 29, 1987 to January 25, 1997, 180 patients diagnosed with astrocytoma with anaplastic foci (AAF) and glioblastoma multiforme (GBM) were treated as outpatients with an average of three weekly intravenous or intraarterial injections of radiolabeled MAb 425. The mean dose was 140 mCi (5.2 GBq). Only one patient who received a single dose of more than 60 mCi (2.2 GBq) experienced acute toxicity. Patients received prior surgery and radiation therapy, with and without chemotherapy. Overall median survival for patients with GBM and AAF was 13.4 and 50.9 months, respectively, with Karnofsky Performance Status (KPS) ranging from 40 to 100 and age ranging from 11 to 75 years. Prognostic factors (KPS and age) correlated positively with increased survival, with KPS the most important determinant of median survival. Data analysis was performed on patients followed 5 years or longer. We conclude that the administration of I-MAb 425 with intensive medical management demonstrates a significant increase in median survival and should be considered a therapeutic regimen for the management of patients with high grade gliomas.     

Radioimmunotherapy of experimental pancreatic cancer with 131I-labeled monoclonal antibody PAM4

We examined the therapeutic efficacy of ¹³¹I-labeled murine monoclonal antibody (MAb) PAM4 against human pancreatic cancers carried as xenografts in athymic nude mice. Animals bearing the CaPanI tumor (0.2 cm³) were either untreated or were given, ¹³¹I-labeled nonspecific Ag8 antibody. By week 7 mean tumor size had grown 16.5 ± 8.4-fold and 4.2 ± 2.5-fold for the untreated and ¹³¹I-Ag8-treated animals, respectively. In contrast, animals administered ¹³¹I-PAM4 exhibited marked regression of tumors to an average of 15% of initial tumor volume. Since most pancreatic cancer patients present with large tumor burdens, the limitation of ¹³¹I-PAM4 treatment with respect to initial tumor size was investigated in animals bearing tumors of approximately 0.5 cm³, 1.0 cm³ and 2.0 cm³. Significant extension of survival time (>3-fold increase) was noted for both the 0.5 cm³ and 1.0 cm^{3 131}I-PAM4-treated groups, compared to their respective untreated controls. Even in the group bearing large 2.0-cm³ tumors, survival was increased 2-fold over the control group. To further improve anti-tumor effects in large tumors, 2 injections of ¹³¹I-PAM4 were administered at a 4-week interval to animals bearing tumors of approximately 1.0 cm³. Significant extended survival was noted for the group receiving 2 doses when compared to the group receiving only 1 dose. Int. J. Cancer 71:660-667, 1997. © 1997 Wiley-Liss, Inc.     

125I-labeled quercetin as a novel DNA-targeted radiotracer

Quercetin is a major flavonoid that is found in most plants; it can intercalate with DNA. The purpose of this study was to investigate radiolabeling of qurecetin with (125)I, DNA binding and cellular process. In this work, quercetin was labeled with Auger emitting nuclide (125)I using chloramine-T. DNA binding of (125)I-quercetin ((125)I-Q) was investigated using cell-free in vitro assay with naked human genomic DNA in agarose plugs. Cellular uptake and nuclei accumulation were evaluated in human prostate cancer cell lines (DU 145). The internalization of (125)I-Q was evaluated with fluorescence microscopy. Cellular damage was monitored by using apoptosis assay. Quercetin was successfully labeled with (125)I, and it was taken up rapidly with cells and accumulated in the cellular nuclei. (125)I-Q-DNA binding was tight with long retention time, and it potentially induced DNA damage. These findings provide for using of (125)I-labeled quercetin as a carrier of Auger electron emitting radionuclide to the cell nuclei for targeted radiotherapy.     

Radioimmunoscintigraphy of human gastric carcinoma xenografts with 125I-labeled monoclonal antibody

A monoclonal antibody (GC 302) established in our laboratory, which was reactive with gastric carcinoma and other epithelial carcinoma but not with normal gastric mucosa or other malignant tumors of mesenchymal origin, was used to investigate the radioimmunolocalization of tumors. Various kinds of target cells (5 X 10(5)) were incubated with 125I-labeled GC 302, and radioactivity was determined with a gamma counter. It was shown that there was a 500- to 1,000-fold increase in counts for gastric carcinoma (NUGC-2, NUGC-4, MKN-28 and MKN-45) as compared to those of normal lymphocytes and about 100-fold increase as compared to melanoma or leukemia. These findings were consistent with those obtained from the study of immunohistochemistry using GC 302. An in vitro assay was also carried out using nude mice bearing gastric cancer and inoculated with 125I-labeled GC 302. There was a 2- to 3-fold increase in radioactivity in the tumor and a 4- to 5-fold increase as compared with the visceral organs. Although the tumor:blood ratio was relatively low, radioimmunoscintigraphy could be done successfully with the aid of computed radiography. We thus conclude that further testing of GC 302 is worthwhile to establish whether or not it is useful for radioimmunoscintigraphy of metastatic lesions of gastric cancer for possible clinical application.     

Specific killing of human melanoma cells by 125I-labeled 9.2.27 monoclonal antibody

The anti-melanoma antibody 9.2.27 localizes to melanoma cells when administered i.v. to melanoma patients, but high doses of this antibody alone have no specific cytotoxic effect in vivo. To determine whether radiolabeled antibodies would exhibit specific antimelanoma cytotoxicity in vitro, cell survival curves were established for NCl-N892 human melanoma cells treated with 125I-labeled 9.2.27 monoclonal antibody. The binding capacity per cell was 5 X 10(5) molecules of 9.2.27 immunoglobulin G, and the association constant of binding was 10(10) M-1. Antibody preparations with specific radioactivities of 9-80 microCi/micrograms were used. Colony-forming ability after in vitro exposure to 125I-9.2.27 was determined by a 1-h antibody incubation at saturating concentrations, washing, and cell freezing for various exposure durations. Colony survival was dose dependent, varying with the radioactivity per cell and the exposure time. The survival curves demonstrated no shoulder effect and had a 37% incremental survival dose of 0.5-0.9 X 10(5) decays/cell. Selective killing of melanoma cells was demonstrated in experiments where NCl-N417 lung cancer cells were mixed with the melanoma cells prior to antibody treatment. The NCl-N417 cells did not express the melanoma-associated antigen, were more sensitive to conventional external irradiation than were the melanoma cells, and could easily be distinguished from them by different growth morphology. In spite of a growth advantage for the melanoma cells in the clonogenic assay, the antigen-negative lung cancer cells selectively survived the treatment and were the only surviving cells after 15 days of exposure.     

Immunotherapy of human glioma xenografts with unlabeled, 131I-, or 125I-labeled monoclonal antibody 425 to epidermal growth factor receptor.

Monoclonal antibody (mAb) 425 (IgG2a) binds to the external domain of the epidermal growth factor receptor. This determinant is highly expressed by human glioma tissues but rarely by normal brain tissues, and is absent on peripheral blood lymphocytes and bone marrow cells. The mAb exerts variable cytotoxic effects against cultured human glioma cells in conjunction with human and murine effector cells. Inhibition of growth of s.c. glioma xenografts in nude mice by the mAb may be mediated by murine macrophages or may be related to the capacity of the mAb to antagonize growth stimulation of glioma cells by epidermal growth factor. In approaches to radioimmunotherapy of human glioma with mAb 425, the 125I-labeled mAb 425 exhibited more significant antitumor effects than the 131I-labeled mAb both in vitro and in vivo in xenotransplanted nude mice. These differences may be due to enhanced nuclear damage caused by 125I-labeled versus 131I-labeled fragments following their internalization into the glioma cells. Our studies provide the rationale for immunotherapy of glioma patients with either unlabeled or 125I-labeled anti-epidermal growth factor receptor mAb 425.     

Radioimmunotherapy of the GW-39 human colonic tumor xenograft with 131I-labeled murine monoclonal antibody to carcinoembryonic antigen

We have investigated the therapeutic efficacy of a single injection of 131I-labeled murine mouse monoclonal antibody (NP-4) against carcinoembryonic antigen using the human colonic tumor xenograft, GW-39, grown in the cheek pouches of adult hamsters. Therapeutic efficacy was dependent on the dose of radioactivity, the specificity of the antibody for the tumor, and the size of the tumor when the radioantibody was administered. A dose of 1 mCi of 131I-labeled NP-4 given 1 day after tumor transplantation completely inhibited the growth of 6 of 11 tumors over a 12-week period, and histological evidence indicated that viable tumor was absent in the tissue remaining at the injection site. Lower doses (0.5 mCi) of 131I-labeled NP-4 inhibited tumor growth over 90% in comparison to untreated animals, but the tumors eventually resumed growth. Delaying the administration of radioantibody for 4 or 7 days after tumor transplantation significantly reduced the therapeutic efficacy. Although the same dose of 131I-labeled irrelevant immunoglobulin G also inhibited tumor growth, 131I-labeled NP-4 was generally 2-3 times more effective in reducing tumor growth than was the control IgG. There was a 13% loss in body weight within 7 days after treatment with 1 mCi, but all the animals regained their weight by day 14, indicating that the level of radioactivity was tolerated well. Dosimetric calculations predicted that over 14 days a dose of nearly 2400 rads was delivered to the tumors with 131I-labeled NP-4. These results confirm our previous studies that 131I-labeled antibody can effectively inhibit tumor growth, but suggest that radioantibody therapy is most effectively administered when there is a low tumor burden.     

Procarbazine and high-dose tamoxifen as a second-line regimen in recurrent high-grade gliomas: a phase II study.

PURPOSE: A phase II study was conducted in patients with high-grade gliomas that recurred after surgery plus radiotherapy and a first-line nitrosourea-based regimen. Our aim was to investigate the efficacy of procarbazine (PCB) combined with high-dose tamoxifen in relation to tumor control, toxicity, and time to progression (TTP). PATIENTS AND METHODS: Fifty-three patients were treated with procarbazine in repeated 30-day courses at 100 mg/m2/d plus tamoxifen 100 mg/d, with a 30-day interval between courses. Thirty-four patients had been pretreated with a first-line nitrosourea-based chemotherapy regimen (group A), and 19 patients had also been pretreated with a second-line chemotherapy regimen consisting of carboplatin and teniposide (group B). Twenty-one of the patients had also been procarbazine pretreated, whereas the remaining 32 patients were not procarbazine pretreated. RESULTS: The response was assessed in 51 patients, 28 of whom had glioblastoma multiforme (GBM) and 23 of whom had anaplastic astrocytoma (AA). There were two complete responses (CR) (4%) and 13 partial responses (PR) (25.5%). The overall response rate (CR + PR) was 29.5% (SE, 6.4; 95% confidence interval [CI], 23 to 35.8). Seventeen patients (32%) had stable disease (SE, 6.2; 95% CI, 21 to 33.6). The median TTP was 13 weeks for patients with GBM and 33 weeks for patients with AA (P = .006). The median survival time (MST) was 27 weeks for patients with GBM and 57 weeks for those with AA (P = .006). CONCLUSION: Combined PCB and tamoxifen as a second-line regimen gave a reasonably high response rate in patients with heavily pretreated high-grade gliomas. However, although it resulted in an improvement in the patients' quality of life and/or performance status, it was not followed by an increased TTP or MST.     

Selective chromosomal damage and cytotoxicity of 125I-labeled monoclonal antibody 17-1a in human cancer cells

A monoclonal antibody, 17-1a, which reacts with antigen expressed in human colon cancers was radiolabeled in high specific activity with 125I. The combination of the antibody and this radionuclide was observed to elicit specific cellular damage after being internalized into cells of the SW1116 human colon cancer cell line. The degree of internalization was quantitatively measured and found to increase over time to 49% after a 48-h incubation period. During this period, significant chromosome aberrations were observed in the SW1116 cell line due to the Auger electrons of 125I. This damage was not observed using Na125I, a nonimmunoreactive radiolabeled antibody, or cells which did not contain the requisite antigen. The number of chromosomal aberrations increased with increasing radioactive concentration of 125I-17-1a. The nuclear damage resulted in specific cellular cytotoxicity and decreased cell survival of SW1116 cells exposed to various concentrations of 125I-17-1a.     

Temozolomide and radiotherapy as first-line treatment of high-grade gliomas

AIMS AND BACKGROUND: Temozolomide, a novel alkylating agent, has shown promising results in the treatment of patients with high-grade gliomas, when used as single agent as well as in combination with radiation therapy. MATERIALS AND METHODS: In this report we retrospectively reviewed the clinical outcome of 128 consecutive patients with a diagnosis of high-grade gliomas referred to our Institutions from April 1994 to November 2001. The first 64 patients were treated with radiotherapy alone and the other 64 with a combination of radiotherapy and temozolomide (31 with radiotherapy and adjuvant temozolomide and 33 with radiotherapy and concomitant temozolomide followed by adjuvant temozolomide). RESULTS: Grade 3 hematological toxicity was scored in 9% of 64 patients treated with radiotherapy and temozolomide. No grade 4 hematological toxicity was reported, and the other acute side effects observed were mild or easily controlled with medications. Age, histology and administration of temozolomide were statistically significant prognostic factors associated with better 2-year overall survival. In contrast, we did not observe a significant difference in overall survival between adjuvant and concomitant/adjuvant temozolomide administration. CONCLUSIONS: We report the favorable results of a schedule combining radiotherapy and temozolomide in the treatment of patients with high-grade gliomas. The literature data and above all the findings of the phase III EORTC-NCIC 26981 trial suggest that actually the schedule can be used routinely in clinical practice. Further clinical studies, using temozolomide in combination with other agents, are required.     

Radioimmunotherapy of intracerebral human glioma xenografts with 131I-labeled F(ab')2 fragments of monoclonal antibody Mel-14

The administration of radiolabeled monoclonal antibodies to improve the treatment of malignant gliomas is dependent upon achieving effective tumor radiation dose while sparing normal tissues. We have evaluated the efficacy of 131I-labeled F(ab')2 fragment of monoclonal antibody Mel-14, an IgG2a reactive with the chondroitin sulfate proteoglycan antigen of gliomas, melanomas, and other neoplasms, in prolonging survival of athymic mice transplanted intracerebrally with D-54 MG human glioma xenografts. Studies indicated that in vitro immunoreactivity, affinity, and tumor localization in vivo of radiolabeled Mel-14 F(ab')2 were maintained at specific activities of 10-13 microCi/micrograms. Intravenous injection of 1500 microCi/115 micrograms or 2000 microCi/154 micrograms 131I-labeled Mel-14 F(ab')2 into mice 6-7 days after xenograft implantation resulted in significant survival prolongation over control animals (P = 0.009 using Wilcoxon rank sum analysis). In another experiment, 1500 microCi/126 micrograms 131I-labeled Mel-14 F(ab')2 improved survival significantly over controls (P = 0.006), while 1500 microCi/220 micrograms 131I-labeled nonspecific antibody did not (P = 0.2). Increasing the injected radiation dose to 3000 microCi 131I-labeled Mel-14 F(ab')2 did not significantly increase survival in tumor-bearing mice, because of supervening radiation toxicity. However, giving 3000 microCi 131I-labeled Mel-14 F(ab')2 in two doses of 1500 microCi, 48 h apart, did significantly prolong animal survival over controls (P = 0.001). Estimated radiation dose to tumor was 915 rad after injection of 3000 microCi 131I-labeled Mel-14 F(ab')2 in two doses, a dose higher than that delivered to normal tissues. The results of this study suggest that radiolabeled Mel-14 F(ab')2 be evaluated as an agent for radioimmunotherapy trials.     

Stem cells as therapeutic vehicles for the treatment of high-grade gliomas

Stem cells have generated great interest in the past decade as potential tools for cell-based treatment of human high-grade gliomas. Thus far, 3 types of stem cells have been tested as vehicles for various therapeutic agents: embryonic, neural, and mesenchymal. The types of therapeutic approaches and/or agents examined in the context of stem cell-based delivery include cytokines, enzyme/prodrug suicide combinations, viral particles, matrix metalloproteinases, and antibodies. Each strategy has specific advantages and disadvantages. Irrespective of the source and/or type of stem cell, there are several areas of concern for their translation to the clinical setting, such as migration in the adult human brain, potential teratogenesis, immune rejection, and regulatory and ethical issues. Nonetheless, a clinical trial is under way using neural stem cell-based delivery of an enzyme/prodrug suicide combination for recurrent high-grade glioma. A proposed future direction could encompass the use of stem cells as vehicles for delivery of agents targeting glioma stem cells, which have been implicated in the resistance of high-grade glioma to treatment. Overall, stem cells are providing an unprecedented opportunity for cell-based approaches in the treatment of high-grade gliomas, which have a persistently dismal prognosis and mandate a continued search for therapeutic options.     

Malignant astrocytomas treated with iodine-125 labeled monoclonal antibody 425 against epidermal growth factor receptor: a phase II trial.

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 intra-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.     

Radioimmunotherapy of human synovial sarcoma using a monoclonal antibody against FZD10

We previously reported Frizzled homolog 10 ( FZD10 ), a member of the Frizzled family, to be a promising therapeutic target for synovial sarcomas. In this report, we established a murine monoclonal antibody (MAb), namely, MAb 92-13 that had specific binding activity against native FZD10 product expressed in synovial sarcoma cell lines. Subsequent immunohistochemical analyses with the MAb 92-13 confirmed an absence or hardly detectable level of FZD10 protein in any normal human organs. We confirmed the specific binding activity of this MAb in vivo after injection of fluorescent-labeled MAb i.p. or i.v. into the mice carrying synovial sarcoma xenografts by the use of the in vivo fluorescent imaging system as well as radioisotopes. Moreover, MAb 92-13 was effectively internalized into the synovial sarcoma cells after its binding to FZD10 on the cell surface. A single i.v. injection of the Yttrium-90 (⁹⁰Y)-MAb 92-13 drastically suppressed tumor growth of synovial sarcoma in mice without any severe toxicity. Median time to tumor progression was 58 days for mice treated with ⁹⁰Y-MAb 92-13 and 9 days for mice treated with non-labeled antibody control or untreated mice (difference = 49 days; P  = 7 × 10⁻⁵). This result indicates that MAb 92-13 could be utilized as the novel treatment modality for synovial sarcoma and other FZD10-positive tumors. ( Cancer Sci 2008; 99: 432–440)     

Gene expression profile as a prognostic factor in high-grade gliomas

Some clinical factors have been useful in predicting prognosis in high-grade gliomas, however, unexpected differences in survival time have generated attempts to search for more precise parameters. It is clear that tumour behaviour depends mostly on gene alterations. Known single gene alterations failed to accurately define survival time, however, recently, the gene profiling based on microarray technology has raised hopes. Our aim was to assess whether the genetic predictor exceeds clinical parameters in the prognosis of malignant gliomas. We performed gene expression analysis of 28 gliomas (3 grade II, 10 grade III and 15 grade IV, according to WHO classification), and 5 control, normal brain samples, using Clontech oligonucleotide arrays with 3,757 known genes. The signal-to-noise statistics was used to separate classes, and the leave-one-out method was used to assess the smallest number of genes make it clear with a minimal cross-validation error. All gliomas, or only high-grade tumours, were clearly separated from the normal brain samples using 7 or 9 most differentially expressed genes. Hierarchical clustering failed, but the fuzzy c-means method was useful in high-grade gliomas to find a gene prediction model, which, with clinical factors, was assessed in survival analysis. Univariate analysis demonstrated that age, WHO grade (IV vs. III), radiation dose (> or = 50 Gy vs. 42 Gy), postoperative KPS score (100 points vs. others), neurological deficit as the first sign of the disease vs. others, and gene expression profile were significant predictors of survival. In multivariate analysis, the gene expression profile remained the only independent predictor (p = 0.007). Thus, our conclusion is that gene expression pattern predicts outcome in high-grade gliomas independently of other factors.     

Pharmacokinetics and tumor localization of 131I-labeled anti-tenascin monoclonal antibody 81C6 in patients with gliomas and other intracranial malignancies

We previously have reported that radioiodinated anti-tenascin monoclonal antibody 81C6 exhibits therapeutic potential against both s.c. and intracranial human glioma xenografts in athymic mice and rats. Herein we report the selective tumor localization of 131I-labeled 81C6 in patients with gliomas and other intracranial malignancies. Nine patients were simultaneously administered 5-50 mg of 131I-labeled 81C6 and 1-2 mg of 125I-labeled 45.6, an isotype-matched control monoclonal antibody. The blood clearance half-time for 81C6, normalized to that of 45.6 in the same patient, appeared to decrease with 81C6 protein dose. Gamma camera images obtained at 1 to 3 days exhibited increased uptake of 131I in regions corresponding to tumor with varying degrees of contrast to surrounding normal brain. Biopsy specimens of tumor and normal brain were obtained and analyzed histologically for tumor content. The average uptake of 81C6 in tumor ranged from 0.6 to 4.3 x 10(-3)% of the injected dose per gram. In patients receiving 20-50 mg of 81C6, the average tumor-to-normal-brain ratio was 25:1 with ratios as high as 200:1 seen in some samples. Localization indices were calculated by normalizing the uptake of 81C6 per gram tumor to the uptake of 81C6 per gram blood and dividing by the same ratio for 45.6 control monoclonal antibody. Localization indices for muscle and brain were about 1, in contrast to up to five for tumor. These studies demonstrate that the tumor uptake of 131I-labeled 81C6 in patients with gliomas and other intracranial malignancies is due to specific processes.