Phase II trial of gefitinib 250 mg daily in patients with recurrent and/or metastatic squamous cell carcinoma of the head and neck

Cetuximab in the treatment of head and neck cancer

Approaches to the treatment of locally advanced and recurrent and/or metastatic squamous cell carcinoma of the head and neck (SCCHN) have been limited by their toxicity. Effective, better tolerated approaches are urgently required. Cetuximab is an immunoglobulin G(1) monoclonal antibody that specifically targets the epidermal growth factor receptor (EGFR), which is commonly expressed in a number of solid tumors, including SCCHN, where it is associated with poor prognosis. Cetuximab is approved in 56 countries for use in the treatment of EGFR-expressing metastatic colorectal cancer that has progressed on irinotecan-containing therapy and has recently received approval in Europe and the USA for use in the treatment of SCCHN. A randomized Phase III study has demonstrated that cetuximab plus radiotherapy can significantly improve locoregional control and prolong overall survival compared with radiotherapy alone. Cetuximab has also been confirmed to be effective as monotherapy in recurrent and/or metastatic SCCHN that has progressed on platinum-containing therapy. Clinical studies have demonstrated that cetuximab is well tolerated and does not significantly increase the side effects associated with radiotherapy or chemotherapy. This article presents the rationale for EGFR inhibition in the management of head and neck cancers, and the preclinical and clinical evidence for the use of cetuximab in the treatment of SCCHN.

Targeting EGF-receptor-signalling in squamous cell carcinomas of the head and neck

Despite significant advances in the use of surgery, chemotherapy and radiotherapy to treat squamous cell carcinoma of the head and neck (SCCHN), prognosis has improved little over the past 30 years. There is a clear need for novel, more effective therapies to prevent relapse, control metastases and improve overall survival. Improved understanding of SCCHN disease biology has led to the introduction of molecularly targeted treatment strategies in these cancers. The epidermal growth factor receptor (EGFR) is expressed at much higher levels in SCCHN tumours than in normal epithelial tissue, and EGFR expression correlates with poor prognosis. Therefore, much effort is currently directed toward targeting aberrant EGFR activity (e.g. cell signalling) in SCCHN. This review discusses the efficacy of novel therapies targeting the EGFR (e.g. anti-EGFR antibodies and EGFR tyrosine kinase inhibitors) that are currently tested in SCCHN patients.

Epidermal Growth Factor Receptor Activation: How Exon 19 and 21 Mutations Changed Our Understanding of the Pathway

The discovery of epidermal growth factor receptor (EGFR) mutations in never-smokers has been the most relevant finding ever in non–small cell lung cancer. When patients whose tumors bear the sensitizing mutations are treated with the tyrosine kinase inhibitors gefitinib or erlotinib, we witness response rates and durations never before reported, including complete responses. At the same time, the presence of EGFR mutations has raised numerous new questions, tantalizing data, and new challenges for treatment. This is particularly true as we try to generalize the findings in lung cancer to other malignancies. The indiscriminate use of gefitinib or erlotinib in the general lung cancer population results in meager survival benefit for patients. Similarly, the tyrosine kinase inhibitors have limited activity in a variety of tumor types with EGFR overexpression. This has led to the question of whether EGFR remains a viable target in patients other than those whose tumors contain mutations, and whether the modest activity of cetuximab in colorectal cancer and head and neck cancer represents all that we can expect from inhibition of this pathway in the absence of mutation. Mechanisms of pathway activation other than mutation have been discovered in recent years, and include overexpression mediated by gene amplification or by amplification of a dinucleotide repeat in the EGFR promoter, mutation of an extracellular region on EGFR generating a mutant protein termed EGFRvIII, and enhanced signaling due to heterodimerization with other members of the EGFR family, particularly overexpression of HER2/HER3. The extent to which these paths to EGFR activation will confer sensitivity to the tyrosine kinase inhibitors or to EGFR monoclonal antibodies is being explored. Thus far, published clinical data suggest that there is little room for the administration of gefitinib or erlotinib in the absence of EGFR mutations. The five articles in this edition of CCR Focus will address the various mechanisms of EGFR pathway activation and provide insight into the potential for translation into clinical relevance.

Clinical implications of the mechanism of epidermal growth factor receptor inhibitors

Novel therapeutic agents that target the epidermal growth factor receptor (EGFR) constitute an important addition to the therapeutic armamentarium for the treatment of metastatic disease. EGFR-targeted agents currently approved by the U.S. Food and Drug Administration include cetuximab, a monoclonal antibody for the treatment of colorectal cancer; and the small-molecule EGFR tyrosine kinase inhibitor (TKI) erlotinib for the treatment of nonsmall cell lung cancer (NSCLC) and pancreatic cancer. Approval of the TKI gefitinib for NSCLC recently was withdrawn. Although both classes of anti-EGFR agents target the same receptor, substantial distinctions regarding their mechanism significantly affect dosing requirements, toxicity profiles, and their use as combination agents.

Epidermal growth factor receptor – targeted molecular therapeutics for head and neck squamous cell carcinoma

Several molecular-targeted therapeutics have been tested in clinical trials for the treatment of head and neck squamous cell carcinoma (HNSCC). Of these, therapeutics targeting the epidermal growth factor receptor (EGFR) have been studied most extensively and some agents have demonstrated measurable clinical effectiveness. However, molecular studies designed to define HNSCC patient subcohorts of likely responders to EGFR-targeted therapy have not identified molecular signatures that correlate with clinical response. Here, the authors summarise the relevant clinical findings and highlight reported molecular correlative studies for EGFR-targeted therapeutics for HNSCC. The authors focus especially on molecular markers evaluated for association with clinical response and include data from EGFR-targeted clinical studies in other cancer sites that they anticipate will be of interest to the head and neck cancer research and treatment communities.

Targeting receptor tyrosine kinases and their signal transduction routes in head and neck cancer

Squamous cell carcinoma of the head and neck (SCCHN) is the sixth most common cancer in the world. At present several therapeutic approaches, including surgical removal, chemotherapy and radiotherapy, are used. Yet a significant number of patients relapse, often with metastases. In an attempt to improve treatment of SCCHN new targeted therapies are emerging. Among them special interest has been devoted to agents that act on the epidermal growth factor receptor (EGFR) and other receptor tyrosine kinases, or the signal transduction routes used by these receptors to induce tumour cell proliferation. Such treatments include monoclonal antibodies and small molecule inhibitors of either the intracellular tyrosine kinase activity of these receptors or relevant signalling intermediates. Here we review the biological bases of these new targeted treatments, with special emphasis on the clinical results that point to an implementation of these drugs into the therapeutic armamentarium against SCCHN.

Epidermal growth factor receptor kinase domain mutations in esophageal and pancreatic adenocarcinomas

PURPOSE

Specific activating mutations within the epidermal growth factor receptor (EGFR) identify a subset of non-small cell lung cancers with dramatic sensitivity to the specific tyrosine kinase inhibitors (TKI), gefitinib and erlotinib. Despite the abundant expression of EGFR protein in a broad range of epithelial cancers, EGFR mutations have not been reported in a substantial fraction of other cancers. Given recent reports of TKI-responsive cases of esophageal and pancreatic cancer, this study was designed to determine the prevalence of EGFR mutations in these gastrointestinal cancers.

EXPERIMENTAL DESIGN

We sequenced exons 18 to 21 of EGFR from 21 cases of Barrett's esophagus, 5 cases of high-grade esophageal dysplasia, 17 cases of esophageal adenocarcinoma, and 55 cases of pancreatic adenocarcinoma. Subsets of esophageal (n = 7) and pancreatic cancer cases (n = 5) were obtained from patients who were subsequently treated with gefitinib or erlotinib-capecitabine, respectively.

RESULTS

Mutations of EGFR were identified in two esophageal cancers (11.7%), three cases of Barrett's esophagus (14.2%), and two pancreatic cancers (3.6%). The mutations consisted of the recurrent missense L858R and in-frame deletion delE746-A750, previously characterized as activating EGFR mutations in non-small cell lung cancer. We also identified the TKI drug resistance-associated EGFR T790M mutation in an untreated case of Barrett's esophagus and the corresponding adenocarcinoma.

CONCLUSION

The presence of activating mutations within EGFR in both esophageal and pancreatic adenocarcinomas defines a previously unrecognized subset of gastrointestinal tumors in which EGFR signaling may play an important biological role. EGFR mutations in premalignant lesions of Barrett's esophagus also point to these as an early event in transformation of the esophageal epithelium. The role of genotype-directed TKI therapy should be tested in prospective clinical trials.

Role of Epidermal Growth Factor Receptor Pathway–Targeted Therapy in Patients With Recurrent and/or Metastatic Squamous Cell Carcinoma of the Head and Neck

The development of epidermal growth factor receptor (EGFR) inhibitors was greeted with tremendous enthusiasm in the therapy of squamous cell carcinoma of the head and neck (SCCHN) based on the nearly universal expression of this protein, the negative prognostic associations with expression, and robust preclinical data. Clinical trials to date have demonstrated modest activity of these drugs as single agents with reproducible major response rates of 5% to 15% in SCCHN depending on agent, dose, and schedule. The biology of responsiveness to these agents remains unclear, although an association of development of cutaneous toxicity with positive outcome has been reported repeatedly. Nevertheless, molecular markers of response or resistance have yet to be fully delineated. In the near future, phase III clinical trials will elucidate the role of these agents in second-line recurrent and/or metastatic (R/M) disease, the combination of EGFR inhibitors with other therapeutic strategies will be broadly advanced, and a set of molecular predictors of benefit will begin to emerge. This article will review the progress in utilization of EGFR inhibitors in R/M SCCHN.

A multidisciplinary approach to squamous cell carcinomas of the head and neck: what is new?

PURPOSE OF REVIEW

The aim of this article is to review progress in the treatment of head and neck squamous cell carcinomas (in the light of the most recent literature). Due to the complexity of the disease the multidisciplinary approach needs also a multidisciplinary knowledge which this review tries to summarize.

RECENT FINDINGS

The multidisciplinary treatment approach to the disease includes predictive and prognostic value of biomolecular and clinical factors, the role of induction chemotherapy and concurrent chemo-radiotherapy, new advances in postoperative treatment, treatment-related side-effects and their impact on patients' quality of life, new targeted therapies and treatment choice for incurable patients. Advances in other disciplines, such as radiation therapy and new imaging techniques, will be considered elsewhere in this journal.

SUMMARY

Major advances derived from the strategic use of different treatment and diagnostic modalities. The importance of a multidisciplinary team and knowledge in the approach of this disease should be stressed. Today, a multidisciplinary diagnostic and treatment philosophy is the tool to guarantee the best treatment plan definition, to prevent and relieve treatment adverse effects with the ultimate goal to improve survival.

Multidisciplinary Symposium on Head and Neck Cancer. 2 December 2005, Philadelphia, PA, USA

The Multidisciplinary Symposium on Head and Neck Cancer focused on the emerging data that underlie optimal treatment for head and neck cancers, with a particular focus on squamous cell carcinoma of the head and neck. In-depth discussions showcased the published Phase II and Phase III data on the treatment of locally advanced disease with both induction chemotherapy and concurrent chemoradiotherapy. Molecular targets of interest and relevance in this tumour type were identified, as were the agents which target these putative proteins or pathways of carcinogenesis. Preliminary results from trials incorporating molecularly-targeted agents have shown a promising role for these compounds in the management of both locally advanced and recurrent/metastatic squamous cell carcinoma of the head and neck. The Symposium brought a clear message. The management of squamous cell carcinoma of the head and neck has evolved considerably, and with the advent of newer chemotherapeutic agents and molecularly targeted therapies, this field will continue to expand over time.