ERBB receptor tyrosine kinases have important roles in human cancer. In particular, the expression or activation of epidermal growth factor receptor and ERBB2 are altered in many epithelial tumours, and clinical studies indicate that they have important roles in tumour aetiology and progression. Accordingly, these receptors have been intensely studied to understand their importance in cancer biology and as therapeutic targets, and many ERBB inhibitors are now used in the clinic. We will discuss the significance of these receptors as clinical targets, in particular the molecular mechanisms underlying response.

ERBB receptors and cancer: the complexity of targeted inhibitors.

Background Cetuximab is effective in platinum-resistant recurrent or metastatic squamous-cell carcinoma of the head and neck. We investigated the efficacy of cetuximab plus platinum-based chemotherapy as first-line treatment in patients with recurrent or metastatic squamous-cell carcinoma of the head and neck. Methods We randomly assigned 220 of 442 eligible patients with untreated recurrent or metastatic squamous-cell carcinoma of the head and neck to receive cisplatin (at a dose of 100 mg per square meter of body-surface area on day 1) or carboplatin (at an area under the curve of 5 mg per milliliter per minute, as a 1-hour intravenous infusion on day 1) plus fluorouracil (at a dose of 1000 mg per square meter per day for 4 days) every 3 weeks for a maximum of 6 cycles and 222 patients to receive the same chemotherapy plus cetuximab (at a dose of 400 mg per square meter initially, as a 2-hour intravenous infusion, then 250 mg per square meter, as a 1-hour intravenous infusion per week) for a maximum of 6 cycles. Patients with stable disease who received chemotherapy plus cetuximab continued to receive cetuximab until disease progression or unacceptable toxic effects, whichever occurred first. Results

/pdf/platinum-based-chemotherapy-plus-cetuximab-in-head-and-neck-2c129qnqh9.pdf

Platinum-Based Chemotherapy plus Cetuximab in Head and Neck Cancer

Summary Background Previous results from our phase 3 randomised trial showed that adding cetuximab to primary radiotherapy increased overall survival in patients with locoregionally advanced squamous-cell carcinoma of the head and neck (LASCCHN) at 3 years. Here we report the 5-year survival data, and investigate the relation between cetuximabinduced rash and survival. Methods Patients with LASCCHN of the oropharynx, hypopharynx, or larynx with measurable disease were randomly allocated in a 1:1 ratio to receive either comprehensive head and neck radiotherapy alone for 6–7 weeks or radiotherapy plus weekly doses of cetuximab: 400 mg/m² initial dose, followed by seven weekly doses at 250 mg/m². Randomisation was done with an adaptive minimisation technique to balance assignments across stratifi cation factors of Karnofsky performance score, T stage, N stage, and radiation fractionation. The trial was un-blinded. The primary endpoint was locoregional control, with a secondary endpoint of survival. Following discussions with the US Food and Drug Administration, the dataset was locked, except for queries to the sites about overall survival, before our previous report in 2006, so that an independent review could be done. Analyses were done on an intention-to-treat basis. Following completion of treatment, patients underwent physical examination and radiographic imaging every 4 months for 2 years, and then every 6 months thereafter . The trial is registered at www.ClinicalTrials.gov , number NCT00004227. Findings Patients were randomly assigned to receive radiotherapy with (n=211) or without (n=213) cetuximab, and all patients were followed for survival. Updated median overall survival for patients treated with cetuximab and radiotherapy was 49·0 months (95% CI 32·8–69·5) versus 29·3 months (20·6–41·4) in the radiotherapy-alone group (hazard ratio [HR] 0·73, 95% CI 0·56–0·95; p=0·018). 5-year overall survival was 45·6% in the cetuximab-plus-radiotherapy group and 36·4% in the radiotherapy-alone group. Additionally, for the patients treated with cetuximab, overall survival was signifi cantly improved in those who experienced an acneiform rash of at least grade 2 severity compared with patients with no rash or grade 1 rash (HR 0·49, 0·34–0·72; p=0·002). Interpretation For patients with LASCCHN, cetuximab plus radiotherapy signifi cantly improves overall survival at 5 years compared with radiotherapy alone, confi rming cetuximab plus radiotherapy as an important treatment option in this group of patients. Cetuximab-treated patients with prominent cetuximab-induced rash (grade 2 or above) have better survival than patients with no or grade 1 rash.

https://www.thelancet.com/pdfs/journals/lanonc/PIIS1470-2045(09)70311-0.pdf

Radiotherapy plus cetuximab for locoregionally advanced head and neck cancer: 5-year survival data from a phase 3 randomised trial, and relation between cetuximab-induced rash and survival.

Purpose To evaluate the antitumor activity and toxicity of single-agent cetuximab in patients with chemotherapyrefractory colorectal cancer whose tumors express the epidermal growth factor receptor. Patients and Methods Phase II, open-label clinical trial. Patients were required to have EGFr expression demonstrated on formalin-fixed paraffin-embedded tumor tissue by immunohistochemical staining before study participation. Patients were required to have received irinotecan, either alone or in a combination regimen, and to have demonstrated clinical failure on this regimen before study entry. Cetuximab was administered weekly by intravenous infusion. The first dose of 400 mg/m 2 was given during the course of 2 hours. Subsequent weekly treatments were given at a dose of 250 mg/m 2 during the course of 1 hour. Results

Phase II Trial of Cetuximab in Patients With Refractory Colorectal Cancer That Expresses the Epidermal Growth Factor Receptor

The molecular basis for breast cancer metastasis to the brain is largely unknown. Brain relapse typically occurs years after the removal of a breast tumour, suggesting that disseminated cancer cells must acquire specialized functions to take over this organ. Here we show that breast cancer metastasis to the brain involves mediators of extravasation through non-fenestrated capillaries, complemented by specific enhancers of blood-brain barrier crossing and brain colonization. We isolated cells that preferentially infiltrate the brain from patients with advanced disease. Gene expression analysis of these cells and of clinical samples, coupled with functional analysis, identified the cyclooxygenase COX2 (also known as PTGS2), the epidermal growth factor receptor (EGFR) ligand HBEGF, and the alpha2,6-sialyltransferase ST6GALNAC5 as mediators of cancer cell passage through the blood-brain barrier. EGFR ligands and COX2 were previously linked to breast cancer infiltration of the lungs, but not the bones or liver, suggesting a sharing of these mediators in cerebral and pulmonary metastases. In contrast, ST6GALNAC5 specifically mediates brain metastasis. Normally restricted to the brain, the expression of ST6GALNAC5 in breast cancer cells enhances their adhesion to brain endothelial cells and their passage through the blood-brain barrier. This co-option of a brain sialyltransferase highlights the role of cell-surface glycosylation in organ-specific metastatic interactions.

/pdf/genes-that-mediate-breast-cancer-metastasis-to-the-brain-zcvu13s4z5.pdf

Genes that mediate breast cancer metastasis to the brain

The epidermal growth factor receptor (EGFR) is a protein tyrosine kinase expressed on many types of tumor cells, including breast, ovarian, bladder, head and neck, and prostatic carcinoma. There seems to be an association between up-regulation of the EGFR and poor clinical prognosis for a number of human cancers. The 225 antibody is a highly specific murine monoclonal antibody that binds specifically to the human EGFR with an affinity equal to its ligand, competes with the ligand for binding, and blocks activation of the receptor tyrosine kinase. In addition, 225 has been shown to inhibit the growth of human tumor xenografts in athymic nude mice. The 225 antibody has recently been chimerized with human IgG1 in its constant region to increase its clinical utility by decreasing the potential for generation of human antimouse antibodies in recipients. This report compares the biological effects of 225 and its chimeric counterpart (designated C225) against established A431 tumor xenografts in nude mice. The results of these experiments indicated that C225 was more effective than 225 in inhibiting tumor growth in this model. In addition, many of the animals treated with C225 were tumor free at the end of each treatment protocol. It was determined that the dissociation constant of C225 was about 5-fold lower than 225. This suggested that the increased capacity of C225 to compete with ligand for binding to the EGFR was responsible for its enhanced in vivo antitumor effect.

https://clincancerres.aacrjournals.org/content/clincanres/1/11/1311.full.pdf

Kazys Zuklys

Papers

Biological efficacy of a chimeric antibody to the epidermal growth factor receptor in a human tumor xenograft model.