The emerging role of cetuximab in head and neck cancer: a 2007 perspective

Tick bites and red meat allergy

PURPOSE OF REVIEW

A novel form of anaphylaxis has been described that is due to IgE antibody (Ab) directed against a mammalian oligosaccharide epitope, galactose-alpha-1,3-galactose (alpha-gal). Ongoing work regarding the cause and distribution of this IgE response is reviewed.

RECENT FINDINGS

Our recent work has identified a novel IgE Ab response that has been associated with two distinct forms of anaphylaxis: immediate-onset anaphylaxis during first exposure to intravenous cetuximab and delayed-onset anaphylaxis 3-6 h after ingestion of mammalian food products (e.g. beef and pork). Further studies strongly suggested that tick bites were a cause, if not the only significant cause, of IgE Ab responses to alpha-gal in the United States and internationally.

SUMMARY

Large numbers of patients with IgE Ab to alpha-gal continue to be identified in the USA and globally. Clinicians should be aware of this IgE response as the reactions often appear to be idiopathic because of the significant delay between eating mammalian meat and the appearance of symptoms.

The contribution of cetuximab in the treatment of recurrent and/or metastatic head and neck cancer

Recurrent and/or metastatic squamous cell carcinoma of the head and neck (HNSCC) continues to be a source of significant morbidity and mortality worldwide. Agents that target the epidermal growth factor receptor (EGFR) have demonstrated beneficial effects in this setting. Cetuximab, a monoclonal antibody against the EGFR, improves locoregional control and overall survival when used as a radiation sensitizer in patients with locoregionally advanced HNSCC undergoing definitive radiation therapy with curative intent. Cetuximab is also active as monotherapy in patients whose cancer has progressed on platinum-containing therapy. In the first-line setting for incurable HNSCC, cetuximab added to platinum-based chemotherapy significantly improves overall survival compared with standard chemotherapy alone. These positive results have had a significant impact on the standard of care for advanced HNSCC. In this review, we will discuss the mechanism of action, clinical data and common toxicities that pertain to the use of cetuximab in the treatment of advanced incurable HNSCC.

EGFR protein overexpression and gene copy number increases in oral tongue squamous cell carcinoma

New promising therapeutic agents targeting epidermal growth factor receptor (EGFR) have been developed although clinical information concerning EGFR status in oral tongue squamous cell carcinoma (OTSCC) is limited. We investigated EGFR protein expression and gene copy numbers in 78 pretreatment OTSCC paraffin samples. EGFR protein expression was found in all 78 tumours, of which 72% showed an intense staining. Fifty-four percent of the tumours had high (> or =four gene copies) EGFR gene copy numbers. EGFR gene copy number was significantly associated with EGFR protein expression (P=0.002). Pretreatment EGFR staining intensity tended to be associated with non-pathological complete remission after preoperative radiotherapy for Stage II OTSCC. No correlation was found between EGFR status and survival. EGFR FISH results were significantly (P=0.003) higher in more advanced tumours (Stages II, III and IV) than in the tumours in Stage I. Non-smokers exhibited a significantly higher EGFR gene copy number and protein overexpression in Stages I and II OTSCC than smokers (P=0.001, P=0.009). In conclusion, EGFR was found to be overexpressed in all OTSCCs making this cancer type interesting for exploring new therapeutic agents targeting the EGFR receptor.

Molecular mechanisms of head and neck cancer

Despite advances in understanding the underlying genetics, squamous cell carcinoma of the head and neck (SCCHN) remains a major health risk and one of the leading causes of mortality in the world. Current standards of treatment have significantly improved long-term survival rates of patients, but second tumors and metastases still remain the most frequent cause of high mortality in SCCHN patients. A better understanding of the underlying genetic mechanisms of SCCHN tumorigenesis will help in developing better diagnostics and, hence, better cures. In this article we will briefly outline the current state of diagnostics and treatment and our understanding of the molecular causes of SCCHN.

Antibody-based cancer therapy

BACKGROUND

The clinical efficacy of mAbs is generally ascribed to interference with signaling pathways leading to arrest of cell-cycle progression and inhibition of tumor growth. Furthermore, mAbs also have the capacity to activate effector functions of the innate immune system and facilitate the destruction of malignant cells.

OBJECTIVES

The induction of tumor-specific immunity is a desired outcome in cancer immunotherapy. The prevailing situation raises one major question that has to be addressed. This is the clear need for the induction of tumor-specific immunity by combining mAb treatment with other modalities of cancer immunotherapy.

METHODS

Through mAb treatment, recent efforts focus at initiating or enhancing active antitumor immune responses by i) potentiating co-stimulation and blocking co-inhibition; and ii) rendering tumors more immunogenic through increased tumor peptide expression.

RESULTS/CONCLUSIONS

In this review, the functional characteristics of mAbs, together with their mechanisms of action and clinical application, is summarized as is the potential of combination immunotherapies using mAbs for the augmentation of adaptive antitumor immunity. The results from preclinical and clinical studies demonstrate that mAbs can also promote tumor-specific active immunity.