Phase I study of anti--epidermal growth factor receptor antibody cetuximab in combination with radiation therapy in patients with advanced head and neck cancer.

PURPOSE: To evaluate the safety, pharmacokinetics, and efficacy of a chimeric anti-epidermal growth factor receptor monoclonal antibody, cetuximab, in combination with radiation therapy (RT) in patients with advanced squamous cell carcinoma of the head and neck. PATIENTS AND METHODS: We treated 16 patients in five successive treatment schedules. A standard dose escalation procedure was used; three patients entered onto the study at each dose level of cetuximab received conventional RT (70 Gy, 2 Gy/d), and the final three patients received hyperfractionated RT (76.8 Gy, 1.2 Gy bid). Cetuximab was delivered as a loading dose of 100 to 500 mg/m(2), followed by weekly infusions of 100 to 250 mg/m(2) for 7 to 8 weeks. Circulating levels of cetuximab during therapy were determined using a biomolecular interaction analysis core instrument. Human antichimeric antibody response was evaluated with a double-antigen radiometric assay. The recommended phase II/III dose was defined as the optimal cetuximab dose level based on the pharmacologic parameters and adverse events. RESULTS: The most commonly reported adverse events were fever, asthenia, transaminase elevation, nausea, and skin toxicities (grade 1 to 2 in most patients). Skin toxicity outside of the RT field was not strictly dose-dependent; however, grade 2 or higher events were observed in patients treated with higher dose regimens. There was one grade 4 allergic reaction. Most acute adverse effects were associated with RT (xerostomia, mucositis, and local skin toxicity). No antibodies against cetuximab were detected. All patients achieved an objective response (13 complete and two partial remissions). CONCLUSION: Cetuximab can be safely administered with RT. The recommended dose for phase II/III studies is a loading dose of 400 to 500 mg/m(2) and a maintenance weekly dose of 250 mg/m(2).

Epidermal growth factor receptor-targeted therapy with C225 and cisplatin in patients with head and neck cancer.

C225, a human-mouse chimerized monoclonal antibody directed against the epidermal growth factor receptor (EGFr), has a synergistic effect with cisplatin in xenograft models. To determine the tumor EGFr saturation dose with C225 and the fate of infused C225, we conducted a Phase Ib study with C225 in combination with cisplatin in patients with recurrent squamous cell carcinoma of the head and neck. Using tumor samples, we assessed tumor EGFr saturation by antibody using immunohistochemistry studies, the EGFr tyrosine kinase assay, and detection of the EGFr/C225 complex formation by immunoblot. Potential candidates were screened for EGFr expression in their tumors, and 12 patients who had high levels of EGFr expression and tumors easily accessible for repeated biopsies (pretherapy, 24 h after first C225 infusion, 24 h before third C225 infusion) were entered at three different dose levels of C225 with a fixed dose of cisplatin. The median value of tumor EGFr saturation increased to 95% at the higher dose levels. EGFr tyrosine kinase activity was significantly reduced after C225 infusion, and EGFr/C225 complexes were also detected at higher doses of C225. The loading dose of C225 at 400 mg/m(2) with a maintenance dose at 250 mg/m(2) achieved a high percentage of saturation of EGFr in tumor tissue, and these doses were recommended for Phases II or III clinical trials. Six (67%) of nine evaluable patients achieved major responses, including two (22%) complete responses. Mild to moderate degrees of allergic reaction and folliculitis-like skin reactions were demonstrated. We conclude that infused C225 binds and significantly saturates tumor EGFr, which may render a high degree of antitumor activity, and provides a novel mechanism for targeting cancer therapy for patients who have EGFr expression in their tumors.

Enhanced apoptosis with combination C225/radiation treatment serves as the impetus for clinical investigation in head and neck cancers.

PURPOSE: Epidermal growth factor receptor (EGFr) is overexpressed in a majority of head and neck squamous cell carcinomas, and this overexpression is associated with a poor prognosis. Therefore, EGFr has become the target of investigations aimed at disabling the receptor to determine whether this process leads to improved tumor kill with conventional treatment. MATERIALS AND METHODS: C225 is an anti-EGFr monoclonal antibody that inhibits receptor activity by blocking the ligand binding site. A panel of human head and neck squamous cell carcinoma cell lines was used to study the combination of C225 and radiation. RESULTS: It was determined that the combination of C225 (5 microgram/mL) delivered simultaneously with radiation (3 Gy) resulted in a greater decrement in cellular proliferation than either treatment alone. This reduction in proliferation correlated with reduced EGFr tyrosine phosphorylation and a reduction in phosphorylated signal transducer and activator of transcription-3 (STAT-3) protein (known to protect cells from apoptosis). Also, the decrement in proliferation correlated with increased apoptotic events, thereby indirectly linking C225/radiation-induced regulation of STAT-3 protein to apoptosis. CONCLUSION: This preclinical work serves as important support for the ongoing clinical investigation of C225 and radiotherapy for patients with head and neck carcinomas. The initial results of these clinical studies have been promising.

Epidermal growth factor receptor blockade by antibody IMC-C225 inhibits growth of a human pancreatic carcinoma xenograft in nude mice.

BACKGROUND: Pancreatic carcinoma is associated with a poor prognosis, and treatment options for patients with this disease are limited. The epidermal growth factor (EGF) receptor and its ligands are overexpressed in human pancreatic carcinoma and may contribute to the pathophysiology of these tumors. METHODS: The anti-EGF receptor monoclonal antibody IMC-C225 was used to determine the effects of EGF receptor blockade on the growth of human pancreatic carcinoma BxPC-3 cells in vitro. Athymic mice bearing established (200 mm(3)) subcutaneous BxPC-3 xenografts were treated with IMC-C225 (17 or 33 mg/kg every 3 days) alone or in combination with 5-fluorouracil (17 mg/kg twice weekly). RESULTS: IMC-C225 inhibited exogenous ligand-stimulated tyrosine phosphorylation of the EGF receptor on BxPC-3 tumor cells. Treatment of BxPC-3 cells with IMC-C225 inhibited DNA synthesis (23.8%) and colony formation in soft agar (45.6%). IMC-C225 treatment significantly suppressed the growth of BxPC-3 tumors compared with treatment with vehicle alone (P = 0.003). Combination therapy with IMC-C225 and the chemotherapeutic agent 5-fluorouracil enhanced the antitumor effects compared with either agent alone and resulted in regression of pancreatic tumors in several animals. Histologic examination of pancreatic tumors from mice treated with IMC-C225 showed extensive tumor necrosis that coincided with a substantial decrease in tumor cell proliferation and an increase in tumor cell apoptosis. CONCLUSIONS: These data suggest that IMC-C225 affects the growth of pancreatic tumors by inhibiting EGF receptor-dependent proliferation and survival, and demonstrates the potential for therapeutic application of IMC-C225 antibody in the treatment of human pancreatic carcinoma.

Phase I studies of anti-epidermal growth factor receptor chimeric antibody C225 alone and in combination with cisplatin.

PURPOSE: The epidermal growth factor (EGF) receptor is frequently overexpressed in epithelial tumors. C225 is a human-to-murine chimeric monoclonal antibody that binds to the receptor and inhibits growth of cancer cells expressing the receptor. We evaluated the pharmacokinetics and toxicity of C225 in patients with advanced tumors overexpressing EGF receptors. PATIENTS AND METHODS: We treated 52 patients in three successive phase I clinical trials of C225 as a single dose (n = 13), weekly multiple dose (n = 17), and weekly multiple dose with cisplatin (n = 22). C225 dose levels were 5, 20, 50, and 100 mg/m(2). In the study combining C225 with cisplatin, limited to patients with either head and neck or non-small-cell lung cancer, C225 was further escalated to 200 and 400 mg/m(2). Cisplatin was given at a dose of 60 mg/m(2) once every 4 weeks, and treatment was continued for up to 12 weeks if no disease progression occurred. RESULTS: C225 displayed nonlinear pharmacokinetics, with antibody doses in the range of 200 to 400 mg/m(2) being associated with complete saturation of systemic clearance. C225 clearance did not change with repeated administration or with coadministration of cisplatin. Antibodies against C225 were detected in only one patient, and C225-associated toxicity was minimal. Patients experiencing disease stabilization were seen in all studies. In the study combining C225 and cisplatin, nine (69%) of 13 patients treated with antibody doses >/= 50 mg/m(2) completed 12 weeks of therapy, and two partial responses were observed. CONCLUSION: C225 has dose-dependent pharmacokinetics, and doses that achieve saturation of systemic clearance are well tolerated. C225 given in combination with cisplatin has biologic activity at pharmacologically relevant doses.

Role of an anti-epidermal growth factor receptor in treating cancer.

Recent technological advances, together with the discovery of the important role many growth factors play in modulating cell proliferation and differentiation, have led to the development of novel therapeutic agents for the treatment of cancer. In particular, advances in hybridoma technology and molecular engineering have permitted the development of humanized or chimeric monoclonal antibodies capable of interfering with growth factor signaling pathways. One promising target of interest is the epidermal growth factor receptor (EGFr), which is activated by the ligands EGF and TGF-alpha. This ligand receptor interaction plays a crucial role in the growth and survival of many human cancers. A chimeric (human/mouse) monoclonal antibody p6tuximab (IMC-C225) targets the EGFr and has potential clinical value as an anticancer agent.

Mouse-human chimeric anti-epidermal growth factor receptor antibody C225 inhibits the growth of human renal cell carcinoma xenografts in nude mice.

The epidermal growth factor (EGF) receptor and its ligand transforming growth factor-alpha (TGF-alpha) are overexpressed in human renal cell carcinoma (RCC). The chimeric anti-EGF receptor monoclonal antibody C225 was used to determine the effects of blocking the EGF receptor on RCC growth both in vitro and in vivo. A panel of RCC cell lines all tested positive at various levels for EGF receptor cell surface expression. C225 inhibited DNA synthesis of cultured A498, Caki-1, SK-RC-4, SK-RC-29, and SW839 cells in a dose-dependent manner, ranging from 20 to 45% inhibition compared with untreated controls. C225 also inhibited exogenous ligand-stimulated tyrosine phosphorylation of EGF receptor on RCC cells. The antitumor effects of C225 on RCC tumor growth were evaluated in ascites, s.c., and orthotopic RCC xenograft models. Mice treated with C225 in a Caki-1 ascites xenograft model showed a significant increase in survival (P = 0.002). All control mice died with ascites tumors by week 9, whereas >70% of C225-treated mice survived beyond 12 weeks. C225 also inhibited the growth of s.c. SK-RC-29 tumors in a dose-dependent manner. Mice treated with C225 (1 mg/dose) displayed a significant decrease in tumor volume compared with mice treated with control antibody (P < 0.05) or vehicle alone (P < 0.01). Lastly, C225 inhibited the growth and metastasis of RCC tumors growing orthotopically in the renal subcapsule of nude mice. Histological examination of RCC tumors from mice treated with C225 showed a substantial decrease in proliferating cell nuclear antigen staining and an increase in tumor cell apoptosis. These data suggest that C225 affects growth of RCC tumors by inhibiting EGF receptor-dependent proliferation and demonstrate the potential for therapeutic application of C225 in the treatment of human renal cancer.

A novel antigen defined by monoclonal antibody CR101 is associated with small cell lung carcinoma.

Small cell lung carcinoma (SCLC) represents about 25% of all lung cancers. Human SCLC shows neuroendocrine features such as the production of neural peptide hormones, marker enzymes and neurosecretory granules, and the expression of neural cell adhesion molecules (NCAMs). Although SCLC is sensitive to both chemotherapy and radiation, prognosis remains poor due to the appearance of post-treatment chemo- and radioresistant variants. Monoclonal antibodies (MAbs) have been developed that bind to SCLC tumor antigens. We have used similar technology to define another SCLC marker designated gP94/115. The MAb CR101 binds to a highly glycosylated, cell-surface antigen associated with SCLC. In vitro expression of the antigen appears to be restricted to cell lines of SCLC origin. Enzymatic removal of the sugars resolves the antigen into two proteins of 94 and 115 kD by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Fluorescence-activated cell sorting (FACS) analysis confirms the antibody's specificity. These results indicate that CR101 may recognize a novel protein expressed by SCLC.

High-level expression of a biologically active human interleukin-6 mutein.

We have constructed two different muteins of interleukin-6 (IL-6) which were expressed in Escherichia coli. Both muteins lack the first 22 N-terminal amino acids of native IL-6 and lack one or the other of the two naturally occurring pairs of cysteines at either position 45 and 51 or position 74 and 84 of IL-6. We found that there was a dramatic increase in the level of IL-6 produced from each mutein clone, compared to the level produced by the wild-type IL-6 clone. We also observed that the yield of soluble and properly refolded mutein IL-6 was highest when the cysteines at position 74 and 84 were left intact. The mutein IL-6 with cysteines at position 74 and 84 was as active as wild-type IL-6 and a lower concentration of the mutein IL-6 was required to reach maximal activity, compared to wild-type IL-6. The mutein IL-6 with cysteines at position 45 and 51 had a much reduced biological activity.

The application of AmpliProbe in diagnostics.

AmpliProbe System is a rapid, enzyme-labeled, non-isotopic probe system that has high sensitivity and flexibility. AmpliProbe System consists of two major components: target-specific "primary" probes and target-independent, enzyme-labeled, signal-generating "secondary" probes. The visualization of the complemental hybridization between the target DNA or RNA and probes is accomplished by an enzymatic chemiluminescent reaction. The AmpliProbe System format allows hybridization and signal visualization to be completed within five to seven hours. In this paper we present several successful applications of AmpliProbe in the detection of infectious disease pathogens and the detection of gene amplification and transcription elevation in the evaluation of oncogenes in cancer research.

Wright's stain in rapid diagnosis of Pneumocystis carinii.

The conventional Hematology Wright's stain has been used in touch preparation from open lung biopsies to identify Pneumocystis carinii. A 100% positive correlation has been found using this rapid and readily available technique when compared to the conventional silver stain and permanent histologic sections.

Induction of T-cells differentiation in vitro by thymus epithelial cells.

Thymus-reticular epithelial cells (TE-cells) were grown in a cell culture devoid of any lymphocytic elements. These cells were able to induce T-cell differentiation in spleen cells from T-dificient mice as expressed by con-A responsiveness and GvH reactivity. It was also shown that xenogeneic rat TE cells were as effective in the induction of T-cell differentiation in vitro as syngeneic TE cells. This system is therefore ideal for the study of T-cell development.