Rebecca A. Herbertson

A phase I clinical trial with monoclonal antibody ch806 targeting transitional state and mutant epidermal growth factor receptors

An array of cell-surface antigens expressed by human cancers have been identified as targets for antibody-based therapies. The great majority of these antibodies do not have specificity for cancer but recognize antigens expressed on a range of normal cell types (differentiation antigens). Over the past two decades, our group has analyzed thousands of mouse monoclonal antibodies for cancer specificity and identified a battery of antibodies with limited representation on normal human cells. The most tumor-specific of these antibodies is 806, an antibody that detects a unique epitope on the epidermal growth factor receptor (EGFR) that is exposed only on overexpressed, mutant, or ligand-activated forms of the receptor in cancer. In vitro immunohistochemical specificity analysis shows little or no detectable 806 reactivity with normal tissues, even those with high levels of wild-type (wt)EGFR expression. Preclinical studies have demonstrated that 806 specifically targets a subset of EGFR expressed on tumor cells, and has significant anti-tumor effects on human tumor xenografts, primarily through abrogation of signaling pathways. The present clinical study was designed to examine the in vivo specificity of a chimeric form of mAb 806 (ch806) in a tumor targeting/biodistribution/pharmacokinetic analysis in patients with diverse tumor types. ch806 showed excellent targeting of tumor sites in all patients, no evidence of normal tissue uptake, and no significant toxicity. These in vitro and in vivo characteristics of ch806 distinguish it from all other antibodies targeting EGFR.

Phase I biodistribution and pharmacokinetic study of Lewis Y-targeting immunoconjugate CMD-193 in patients with advanced epithelial cancers.

Purpose: This phase I study explored the biodistribution and pharmacokinetics of the immunoconjugate CMD-193 [a humanized anti–Lewis Y (Ley) antibody conjugated with calicheamicin in patients with advanced cancers expressing the Ley antigen. Experimental Design: The primary objectives were to determine biodistribution and pharmacokinetics of CMD-193. Secondary objectives included response rates and change in tumor metabolism. Patients with progressive, measurable, and Ley positive malignancies were eligible for enrollment in one of two dose cohorts, 1.0 and 2.6 mg/m2. The first cycle was trace labeled with 111In for biodistribution assessment using γ camera imaging. Subsequent cycles were administered every 3 weeks up to a maximum of six cycles, depending on toxicity and response. Pharmacokinetic analysis was based on radioassay and ELISA. Results: Nine patients were enrolled in the study. Biodistribution images showed initial blood pool activity, followed by markedly increased hepatic uptake by day 2, and fast blood clearance in all patients. There was low uptake in tumor in all patients. The overall T½β of 111In-CMD-193 was 102.88 ± 35.67 hours, with no statistically significant difference between the two dose levels. One patient had a partial metabolic response on 18F-fluorodeoxyglucose-positron emission tomography (18F-FDG PET) after four cycles, but no radiological responses were observed. Myelosuppression and effects on liver function were the most significant adverse effects. Conclusions: CMD-193 shows rapid blood clearance and increased hepatic uptake compared with prior studies of the parental antibody hu3S193. These results highlight the importance of biodistribution and pharmacodynamic assessment in early phase studies of new biologics to assist in clinical development. (Clin Cancer Res 2009;15(21):6709–15)

Established, emerging and future roles of PET/CT in the management of colorectal cancer

Positron-emission tomography-computed tomography (PET/CT) is rapidly being integrated into the imaging pathways of several different tumour types, most frequently using the glucose analogue 2- [(18)F]-fluoro-2-deoxy-D-glucose (FDG). Integrated FDG-PET/CT combines functional and anatomical imaging to improve sensitivity and specificity of tumour detection. The aim of this article is to review the established, emerging, and future roles of FDG-PET/CT in the management of patients with colorectal cancer (CRC).

Motesanib diphosphate (AMG 706), an oral angiogenesis inhibitor, demonstrates clinical efficacy in advanced thymoma

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Medullary carcinoma of the thyroid in a patient with colon cancer and a rising carcinoembryonic antigen level.

has also been advocated for accurate preoperative localization of parathyroid adenomas, particularly if they are in ectopic mediastinal locations. Multimodality imaging such as SPECT-CT image fusion and hybrid SPECT-CT cameras may have a useful role to play in the diagnosis and management of this condition. Radio-guided surgery, already well established in sentinel lymph node biopsy, is otherwise underutilized in Australia to guide minimally invasive surgery. Minimally invasive radio-guided surgery may be facilitated by accurate preoperative localization with hybrid imaging.