Gefitinib (ZD1839, Iressa) as palliative treatment in recurrent or metastatic head and neck cancer

Molecularly targeted agents in the treatment of recurrent or metastatic squamous cell carcinomas of the head and neck

Proof of principle that molecularly targeted therapy is a valid therapeutic approach for squamous cell carcinoma of the head and neck (SCCHN) has emerged with epidermal growth factor receptor targeting agents. Other interesting targets, such as Src, insulin-like growth factor 1 receptor, and the proteasome, have been shown in vitro to play key roles in SCCHN, and their inhibition is currently being studied in phase II trials. Identification of predictive biomarkers of resistance or sensitivity to these therapies remains one of the main challenges in the optimal selection of patients most likely to benefit from them. However, clinical trials with these novel agents need to be designed rationally to improve the overall outcome of patients. Given the emerging evidence that human papilloma virus-related SCCHN is a distinct disease, it should be studied in specific trials.

EGFR inhibition as a therapy for head and neck squamous cell carcinoma

BACKGROUND

Improved understanding of disease biology of head and neck squamous cell carcinoma (HNSCC) with nearly universal expression of EGFR has led to the introduction of targeted therapies to interrupt signalling of this negative prognostic marker.

OBJECTIVE

We performed a literature review on the mechanisms and efficacy of anti-EGFR antibodies and EGFR tyrosine kinase inhibitors in patients with locally advanced or recurrent/metastatic HNSCC.

RESULTS/CONCLUSION

Clinical trials in HNSCC have administered EGFR directed drugs as single agents, in combination with chemotherapy or radiotherapy and demonstrated a good safety profile with antitumour activity in a subgroup of patients. The biology of responsiveness is still unclear, although there is growing evidence of an association of skin toxicity or presence of shorter EGFR intron 1 cytosine-adenine repeats with positive outcome.

Targeting important pathways in head and neck cancer: from the bench to the clinic

Radiation therapy as single or combined modality (concurrent chemoradiotherapy) has been the cornerstone of treatment for squamous cell carcinoma of the head and neck for a long time. Fortunately, advances in tumor biology have provided new insights of tumor proliferation, metastases, migration and cell cycle regulation. The success seen with the use of cetuximab alone or in combination with conventional treatments has led the roadmap to discover other potential target mechanisms which may translate into better response rate with less local and systemic toxicity and improved overall survival. In this review, we discuss other cellular pathways that have shown to be involved in the carcinogenesis of squamous cell carcinoma of the head and neck and the actual efforts to target these mechanisms.

A phase I/II trial of gefitinib and radiotherapy in patients with locally advanced inoperable squamous cell carcinoma of the head and neck

Two different doses of gefitinib, administered along with standard radiation therapy, were tested in locally advanced inoperable head and neck cancer with the aim of finding the maximum tolerated dose and assessing the toxicity and activity of the combination. The standard '3+3' design was used for the phase I study. Radiation therapy was given according to conventional dose and schedule. Gefitinib dose escalation was stopped if more than one-third of patients of a given cohort had dose-limiting toxicity. Dose-limiting toxicity was observed in three of four patients treated at the dose of 500 mg, and included grade 3 stomatitis in three patients and grade 3 liver toxicities in one patient. The dose level of 250 mg was recommended for the phase II study. Six confirmed objective responses were observed among 16 patients. Our results do not support further trials with gefitinib and radiation therapy, according to our schedule, in this patient population. Integration of gefitinib within chemoradiotherapy regimens and combination with other biological therapies may represent the next challenge.

Targeting epidermal growth factor receptor and SRC pathways in head and neck cancer

Epidermal growth factor receptor (EGFR), a member of the ErbB family of receptor tyrosine kinases (RTKs), is highly expressed in head and neck squamous cell carcinoma (HNSCC) where increased EGFR expression levels in tumors are associated with decreased survival. HNSCC patient responses to EGFR-targeted monotherapies in clinical trials, though significant, have been limited. Tumor signaling pathway components that work in cooperation with EGFR or provide compensation for the loss of EGFR-initiated signaling will be ideal targets for therapies to be used in combination with EGFR-targeted agents. Based on the current understanding of molecular signaling pathways and available agents, ErbB family-targeted and Src family-targeted agents represent strategies for further exploration. Here, we discuss agents targeting ErbB and Src family kinases in clinical development, provide an overview of completed and ongoing clinical trials, and outline a molecular rationale for combining ErbB- and Src-targeted therapeutics.

Phase II Trial of Sorafenib in Patients With Recurrent or Metastatic Squamous Cell Carcinoma of the Head and Neck or Nasopharyngeal Carcinoma

Purpose

To determine the efficacy and safety of single-agent sorafenib in patients with recurrent and/or metastatic squamous cell carcinoma of the head and neck (SCCHN) and nasopharyngeal carcinoma (NPC).

Patients and Methods

In this single-arm phase II trial, oral continuous sorafenib was administered in 28-day cycles. Patients had ≤ one line of chemotherapy for recurrent and/or metastatic disease, Eastern Cooperative Oncology Group performance status of ≤ 2, and adequate organ function. At the end of stage 1, efficacy criteria for further accrual were not met, but the study was amended to enroll an additional five patients for paired tumor biopsies.

Results

Twenty-seven and 26 patients were eligible for toxicity and efficacy evaluations, respectively. One patient (3.7%; 95% CI, 0.1% to 19.0%) achieved a partial response. Disease stabilization was maintained in 10 patients (37.0%; 95% CI, 22.4% to 61.2%). The median time to progression was 1.8 months (95% CI, 1.6 to 3.4 months), and median overall survival time was 4.2 months (95% CI, 3.6 to 8.7 months). Sorafenib was well tolerated with few grade 3 and no grade 4 toxicities. Biomarker analysis of paired tumor samples before and after treatment with sorafenib revealed a decrease of pERK in all five patients, with a decrease in Ki67 in four patients, consistent with a disruption of ERK signaling. The antiapoptotic protein Mcl-1 was downregulated in four patients, and there was also evidence of antiangiogenic activity.

Conclusion

Sorafenib was well tolerated and had modest anticancer activity comparable to monotherapy with other targeted agents in this group of patients. Further development in combination with radiation or other agents may be warranted.

Dual EGFR and mTOR targeting in squamous cell carcinoma models, and development of early markers of efficacy

The epidermal growth factor receptor (EGFR) is a validated target in squamous cell carcinoma (SCC) of the head and neck. Most patients, however, do not respond or develop resistance to this agent. Mammalian target of rapamycin (mTOR) is involved in the pathogenesis of SCC of the head and neck (SCCHN). This study aimed to determine if targeting mTOR in combination with EGFR is effective in SCC, and to develop early pharmacodynamic markers of efficacy. Two SCC cell lines, one resistant (HEP2) and one of intermediate susceptibility (Detroit 562) to EGFR inhibitors, were xenografted in vivo and treated with an mTOR inhibitor (temsirolimus), an EGFR inhibitor (erlotinib) or a combination of both. Temsirolimus exerted superior growth arrest in both cell lines than erlotinib. The combined treatment resulted in synergistic antitumor effects in the Detroit 562 cell line. Immunohistochemical assessment of pharmacodynamic effects in fine-needle aspiration (FNA) biopsies early after treatment using phospho MAPK, Phospho-P70 and Ki67 as end points demonstrated pathway abrogation in the Detroit 562 tumours treated with the combination, the only group where regressions were seen. In conclusion, an mTOR inhibitor showed antitumor activity in EGFR-resistant SCC cell lines. Marked antitumor effects were associated with dual pathway inhibition, which were detected by early FNA biopsies.

Advances in the biology of oral cancer

The incidence of oral cancer remains high and is associated with many deaths in both Western and Asian countries. Several risk factors for the development of oral cancer are now well known, including smoking, drinking and consumption of smokeless tobacco products. Genetic predisposition to oral cancer has been found in certain cases but its components are not yet entirely clear. In accordance with the multi-step theory of carcinogenesis, the natural history of oral cancer seems to gradually evolve through transitional precursor lesions from normal epithelium to a full-blown metastatic phenotype. A number of genomic lesions accompany this transformation and a wealth of related results has appeared in recent literature and is being summarized here. Furthermore, several key genes have been implicated, especially well-known tumor suppressors like the cyclin-dependent kinase inhibitors, TP53 and RB1 and oncogenes like the cyclin family, EGFR and ras. Viral infections, particularly with oncogenic HPV subtypes and EBV, can have a tumorigenic effect on oral epithelia and their role is discussed, along with potential therapeutic interventions. A brief explanatory theoretical model of oral carcinogenesis is provided and potential avenues for further research are highlighted.

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.

Pharmacogenomics of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors

The EGFR is a validated anticancer target whose successful exploitation has added novel agents to our current treatment protocols. Subsets of patients have shown to benefit the most from these therapies, and though these differential responses have yet to be completely defined, they are mostly of genetic nature. Egfr amplifications have shown to increase sensitivity to both small molecule inhibitors and specific monoclonal antibodies targeting the EGFR. A somatic/germline egfr intron 1 CA repeat sequence polymorphism has shown to have an important role in the control of EGFR protein expression, and has been linked to an increased risk of familial breast cancer, a worse outcome in patients with colorectal cancer, and anti-EGFR treatment efficacy in preclinical models. Egfr activating mutations have been recently described in lung cancer linking a cluster of genotypes with sensitivity to EGFR tyrosine kinase pharmacological inhibition. Despite the initial excitement that this discovery elicited, follow-up reports have not unequivocally confirmed this finding, and these drugs have been solidly efficacious both in individual patients and in diseases generally lacking egfr mutations such as pancreas cancer. We are witnessing exciting developments in the field of the pharmacogenomics of cancer, and this has particularly evolved in the area pertaining EGFR tyrosine kinase inhibitors. This review will discuss the background and currently available preclinical and clinical data.