Current and Emerging Molecular Therapies for Head and Neck Squamous Cell Carcinoma

Head and neck cancer affects nearly 750,000 patients, with more than 300,000 deaths annually. Advances in first line surgical treatment have improved survival rates marginally particularly in developed countries, however survival rates for aggressive locally advanced head and neck cancer are still poor. Recurrent and metastatic disease remains a significant problem for patients and the health system. As our knowledge of the genomic landscape of the head and neck cancers continues to expand, there are promising developments occurring in molecular therapies available for advanced or recalcitrant disease. The concept of precision medicine is underpinned by our ability to accurately sequence tumour samples to best understand individual patient genomic variations and to tailor targeted therapy for them based on such molecular profiling. Not only is their purported response to therapy a factor of their genomic variation, but so is their inclusion in biomarker-driven personalised medicine therapeutic trials. With the ever-expanding number of molecular druggable targets explored through advances in next generation sequencing, the number of clinical trials assessing these targets has significantly increased over recent years. Although some trials are focussed on first-line therapeutic approaches, a greater majority are focussed on locally advanced, recurrent or metastatic disease. Similarly, although single agent monotherapy has been found effective in some cases, it is the combination of drugs targeting different signalling pathways that seem to be more beneficial to patients. This paper outlines current and emerging molecular therapies for head and neck cancer, and updates readers on outcomes of the most pertinent clinical trials in this area while also summarising ongoing efforts to bring more molecular therapies into clinical practice.

A phase II study of poziotinib in patients with recurrent and/or metastatic head and neck squamous cell carcinoma

Background

In phase I studies, poziotinib has shown meaningful efficacy against various types of cancers. This phase 2 study aimed to investigate the efficacy and safety of poziotinib in recurrent and/or metastatic head and neck squamous cell carcinoma (R/M‐HNSCC).

Methods

Overall, 49 patients were enrolled (median age, 62 years; age range, 21–78 years). Patients received a median of two prior treatments including chemotherapy and others and received 12 mg poziotinib orally once daily as part of a 28‐day cycle. The primary endpoint was objective response rate (ORR), and the secondary endpoints were progression‐free survival (PFS) and overall survival (OS). Targeted capture sequencing was performed using available tissues to identify translational biomarkers related to clinical response.

Results

ORR was 22.4%, median PFS was 4.0 months (95% confidence interval [CI], 1.8–6.2 months), and median OS was 7.6 months (95% CI, 4.4–10.8 months). The most common treatment‐related adverse events were acneiform rash (85%) and mucositis (77%). A grade 3 or higher adverse event was acneiform rash (3%). Targeted capture sequencing was performed in 30 tissue samples. TP53 and PIK3CA were the most frequently mutated genes (43%), followed by CCND1 (33%) and EGFR (30%). Mutations in ERBB2, ERBB3, and ERBB4, which are HER family genes, were observed in 17%, 13%, and 10% samples, respectively. There was no difference in the frequency of somatic mutations in the HER family genes between the clinically benefitted and non‐benefitted groups.

Conclusion

Compared to other pan‐HER inhibitors, poziotinib showed clinically meaningful efficacy in heavily treated R/M‐HNSCC.

Clinical trial registration number.

NCT02216916.

Novel induction therapy transoral surgery treatment paradigm with risk-adapted adjuvant therapy for squamous cell carcinoma of the head and neck - Mature clinical and functional outcomes

OBJECTIVE

Induction chemotherapy in head and neck squamous cell carcinoma (HNSCCA) has principally been studied prior to radiation therapy. We evaluated pre-operative induction therapy followed by surgery followed by risk-adapted adjuvant therapy. This report details the mature 5-year survival statistics, clinical and functional outcomes.

METHODS

An IRB-approved single institution prospective phase II clinical trial from October 2012 to November 2016 was conducted for patients with transorally-resectable American Joint Committee on Cancer 7th ed. stage III/IV HNSCCA. Patients were treated once weekly for six weeks with a multi-drug induction regimen of carboplatin, paclitaxel and daily lapatinib followed by transoral surgery and neck dissection. Patients were then stratified based on pathologic response to either observation or adjuvant therapy. Survival statistics and functional patient outcomes were analyzed. Specifically, peri-operative outcomes were analyzed and compared to a matched surgical cohort.

RESULTS

38/40 enrolled patients completed trial therapy. Median hospital stay was 3 days with 9/38 patients receiving a PEG (median 46 days). Median NPO status was 1 day, with a median return to a regular diet in 16 days. Mean patient weight was well preserved from pretreatment to 1 year after surgery (85.1 kg (95% CI 79.6-90.7) vs 83.1 kg (95% CI 77.7-88.6 kg) respectively). Of the 38 patients who completed trial therapy; DSS, PFS and OS were 100%, 97% and 97% respectively with median follow up of 4.9 years (3.33-7.25).

CONCLUSION

Transoral surgery was feasible following this novel induction regimen with excellent peri-operative, functional and longterm survival outcomes.

Combined modality treatment of laryngeal squamous cell carcinoma

Squamous cell carcinoma of the larynx is a major public health concern; it causes substantial morbidity and mortality, and arises chiefly as a result of tobacco and alcohol consumption. Early stage disease is best treated with radiation or surgery alone, but for patients with more locally advanced squamous cell carcinoma of the larynx, combined modality treatment has been shown to benefit selected patients, particularly when cisplatin-based chemotherapy and concurrent radiation therapy are employed, with or without altered fractionated radiation therapy. Substantial laryngectomy-associated quality-of-life decrements can be avoided in selected, potentially resectable patients with organ-sparing approaches, without sacrificing survival. Recently, trials have addressed the role of targeted systemic agents to the epidermal growth factor receptor, and other targets are under investigation. The addition of induction chemotherapy to concurrent chemoradiotherapy is a promising treatment strategy that warrants further evaluation, but has not yet emerged as a standard of care; the toxicity of such regimens must be balanced with the potential benefits on a case-by-case basis, and functional outcomes are often quite variable. Treatment planning, management and follow-up are complex, and thus should ideally be performed in a comprehensive, multidisciplinary fashion, in a center accustomed to a high volume of such cases. Future research directions are described herein.

Targeting epidermal growth factor receptor signaling in the treatment of head and neck cancer

In this review, key aspects of epidermal growth factor receptor (EGFR) biology and the fruitful translation of these fundamental findings into recent treatment advances in head and neck squamous cell cancer (HNSCC) are highlighted. In contrast to a number of contemporary reviews of the EGFR, many of which focus on colorectal and nonsmall cell lung cancer, this review discusses the EGFR as a validated therapeutic target in HNSCC. Recent data confirm a survival advantage for the addition of the anti-EGFR monoclonal antibody cetuximab to definitive radiation therapy in locoregionally advanced HNSCC patients, as well as palliative benefits for patients with incurable recurrent and metastatic HNSCC. Small-molecule EGFR tyrosine kinase inhibitors also show considerable promise in this disease, both alone and in combination with radiation and chemotherapy. Both classes of anti-EGFR agent are generally well tolerated, with side effects (notably skin rash) that are distinct from the toxicities of conventional chemotherapy. Ongoing clinical trials will more clearly define the role for EGFR inhibitors in all treatment phases of HNSCC.

Promising new molecular targeted therapies in head and neck cancer

Despite advances in multimodality therapies for the treatment of squamous cell carcinoma of the head and neck (SCCHN), survival rates, functional outcomes and toxicities of therapy remain poor. The recognition of the prognostic value of human papillomavirus (HPV) status, and the advent of biologically targeted therapies with potential for decreased toxicities and increased selectivity, represent significant developments in our understanding of SCCHN. Targeted agents currently approved or under investigation for SCCHN include epidermal growth factor receptor (EGFR) monoclonal antibodies (cetuximab, panitumumab, zalutumumab, nimotuzumab), EGFR tyrosine kinase inhibitors (gefitinib, erlotinib, lapatinib, afatanib, dacomitinib), vascular endothelial growth factor receptor (VEGFR) inhibitors (bevacizumab, sorafenib, sunitinib, vandetanib) and various inhibitors of other pathways and targets, including phosphatidylinositol 3' kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR), MET and insulin-like growth factor receptor (IGF-1R). On-going clinical trials are evaluating these emerging agents and their combinations in the treatment of SCCHN.

New approaches to EGFR inhibition for locally advanced or metastatic squamous cell carcinoma of the head and neck (SCCHN)

Despite recent advances in radiotherapy and chemotherapy, survival rates for squamous cell carcinoma of the head and neck (SCCHN) have remained poor. The focus of SCCHN therapy has more recently shifted to the molecular level, particularly the epidermal growth factor receptor (EGFR/ErbB) pathway. Several agents that target the EGFR pathway, including monoclonal antibodies and tyrosine kinase inhibitors, are under investigation for SCCHN. Searches of PubMed and results of key oncology congresses were performed to identify relevant articles and abstracts. The EGFR-targeted monoclonal antibody cetuximab is approved for the treatment of locally advanced SCCHN in combination with radiotherapy, for first-line treatment of recurrent or metastatic SCCHN in combination with platinum-based chemotherapy and 5-fluorouracil, and for recurrent or metastatic SCCHN following progression with platinum-based chemotherapy. Other investigational EGFR-targeted monoclonal antibodies (e.g., panitumumab, nimotuzumab, zalutumumab) are in clinical development for SCCHN. Inhibition of the tyrosine kinase domain of EGFR has also been explored as a therapeutic approach in SCCHN using small-molecule reversible inhibitors, such as gefitinib and erlotinib. However, a key challenge in SCCHN is the development of resistance, and strategies are being pursued to delay or overcome resistance to EGFR-targeted agents. These strategies include development of agents that inhibit multiple ErbB receptors simultaneously (e.g., lapatinib) or that bind multiple ErbB family receptors irreversibly (e.g., afatinib, PF-00299804) and investigation of combinations of agents that target multiple pathways implicated in the pathogenesis of SCCHN. Ongoing large clinical trials are evaluating these emerging agents and combinations for the treatment of SCCHN.

A phase II trial of dacomitinib, an oral pan-human EGF receptor (HER) inhibitor, as first-line treatment in recurrent and/or metastatic squamous-cell carcinoma of the head and neck

BACKGROUND

An open-label, multicenter, single-arm phase II trial was conducted to investigate the clinical activity of dacomitinib in recurrent/metastatic squamous-cell carcinoma of the head and neck (RM-SCCHN).

PATIENTS AND METHODS

Eligible patients were administered dacomitinib at 45 mg orally daily, in 21-day cycles. Primary end point was objective response rate.

RESULTS

Sixty-nine patients were enrolled with a median age of 62 years. Among response-evaluable patients, 8 [12.7%, 95% confidence interval (CI) 5.6% to 23.5%] achieved a partial response and 36 (57.1%) had stable disease, lasting ≥24 weeks in 9 patients (14.3%). The median progression-free survival (PFS) was 12.1 weeks and the median overall survival (OS) was 34.6 weeks. Most adverse events (AEs) were tolerable. The most common grade 3 or higher treatment-related AEs were diarrhea (15.9%), acneiform dermatitis (8.7%), and fatigue (8.7%). Treatment-related AEs led to at least one dose interruption in 28 (40.6%) patients and dose reductions in 26 (37.7%). Permanent treatment discontinuation occurred in 8 (11.6%) patients due to treatment-related AEs.

CONCLUSIONS

Dacomitinib demonstrated clinical activity in RM-SCCHN, and the primary end point of this study was met. The toxicity profile of this agent was generally manageable with dose interruptions and adjustments.

Molecular-targeted therapies in head and neck cancer

The increasing understanding of tumor biology has opened the door to a new class of biological agents directed at specific molecular targets in the treatment of squamous cell carcinomas of the head and neck. These targeted agents present the opportunity to more effectively attack the crucial cellular pathways contributing to tumor growth and survival, while minimizing toxicity. Cetuximab, which targets epidermal growth factor (EGF) receptor signaling, was the first such biological agent to be proven effective in head and neck squamous cell cancers. Currently, there are dozens of targeted agents at various stages of testing for use in the treatment of head and neck cancers. In this article, we review strategies aimed at key pathways, including EGF receptor signaling, the Vascular Endothelial Growth Factor (VEGF) pathway, and PI3K/AKT/mammalian target of rapamycin activation.

The role of cetuximab in the management of head and neck cancers

INTRODUCTION

The standard of care for patients with locally-advanced head and neck cancer is chemoradiation or surgical resection followed by radiation treatment with or without chemotherapy and despite aggressive, multimodality therapies with their associated toxicities, attempts are being made to improve efficacy while reducing toxicity. Cetuximab is a chimeric mAb directed against the EGFR that showed clinical activity in squamous cell carcinoma of head and neck (SCCHN).

AREAS COVERED

Cetuximab is beneficial in recurrent and metastatic setting, as well as in the definitive setting. In a landmark study by Bonner et al., cetuximab was found to be effective in prolonging survival in conjunction with radiation treatment in locally-advanced tumors versus radiation therapy alone. The Erbitux in First-Line Treatment of Recurrent or Metastatic Head and Neck Cancer (EXTREME) trial also showed an improvement in conjunction with chemotherapy in recurrent and metastatic tumors.

EXPERT OPINION

Cetuximab is an important therapeutic option in SSCHN, and will continue to be used in metastatic and definitive settings. While cetuximab is a valuable tool in the treatment of SCCHN, more studies are needed to maximize the efficacy of this mAb in clinical settings and to identify the subpopulation of patients that truly benefit from its use.

Molecularly targeted therapies in head and neck cancers

Head and neck cancers (HNC) are 6th most common malignancies according to the incidence rate. Over 85% of tumors of this region are epithelial tumors, especially squamous cell carcinomas (head and neck squamous cell carcinomas - HNSCC). Surgery, chemotherapy and radiotherapy are still the standard for the treatment of HNC. Despite the great development of the various methods of treatment, survival of patients have not improved significantly over the last 30 years, with the overall, 5-year survival not exceeding 50%. Progress in understanding the biology of cancer leads to personalization of therapy and introduction of drugs with molecular mechanism of action to everyday practice. At present, the effectiveness of monoclonal antibodies against EGFR in the treatment of HNSCC has already been proven. Cetuximab in combination with radiotherapy was found to be effective in patients with advanced and locally advanced HNSCC. There are also some promising results of phase III trials with zalutumumab and panitumumab. Initial efficacy of sorafenib (an inhibitor of the intracellular domain of VEGFR, PDGFR and c-Kit) and afatinib (an irreversible inhibitor of pan-HER tyrosine kinase) have been demonstrated. Great hopes for the future are linked with the potential use of STAT3, EGFRvIII, abnormal proteins K-ras, H-ras and PTEN as well as proteasome as a target for therapy.

Effects of lapatinib monotherapy: results of a randomised phase II study in therapy-naive patients with locally advanced squamous cell carcinoma of the head and neck

BACKGROUND

Lapatinib is a dual inhibitor of epidermal growth factor receptor (EGFR) and human EGFR-2 (HER-2) tyrosine kinases. This study investigated the pharmacodynamic and clinical effects of lapatinib in patients with locally advanced squamous cell carcinoma of the head and neck (SCCHN).

METHODS

In total, 107 therapy-naive patients with locally advanced SCCHN were randomised (2 : 1) to receive lapatinib or placebo for 2-6 weeks before chemoradiation therapy (CRT). Endpoints included apoptosis and proliferation rates, clinical response, and toxicity.

RESULTS

Versus placebo, lapatinib monotherapy did not significantly increase apoptosis detected by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick-end labelling or caspase-3 assays. A statistically significant decrease in proliferation using Ki67 assay was observed (P=0.030). In a subset of 40 patients that received 4 weeks of lapatinib or placebo, objective response rate (ORR) was 17% (n=4/24) vs 0% (n=0/16). In the lapatinib single-agent responders, all had EGFR overexpression, 50% had EGFR amplification, and 50% had HER2 expression by immunohistochemistry (including one patient with HER2 amplification). However, these patients showed variable modulation of apoptosis, proliferation, and phosphorylated EGFR on drug treatment. Following CRT, there was a statistically non-significant difference in ORR between lapatinib (70%) and placebo (53%). There was no clear correlation between changes in apoptosis or proliferation and response to chemoradiation. Mucosal inflammation, asthenia, odynophagia, and dysphagia were the most commonly reported adverse events with lapatinib.

CONCLUSION

Short-term lapatinib monotherapy did not demonstrate apoptotic changes, but provided evidence of clinical activity in locally advanced SCCHN, and warrants further investigation in this disease.

Molecular biology of squamous cell carcinoma of the head and neck: relevance and therapeutic implications

More than 90% of all head and neck cancers are squamous cell carcinoma. Despite advances in the management of patients with this disease, the survival rate has not been significantly improved. Several mechanisms of carcinogenesis have been elucidated and molecular targeted agents seem to be promising therapeutic tools. Cetuximab, a monoclonal antibody inhibitor of the EGF receptor, improves survival rates in association with radiotherapy in advanced squamous cell carcinoma of the head and neck (SCCHN) or in palliative disease, and is nowadays the only targeted agent approved in this indication. Other targeted agents are also clinically relevant to the treatment of different malignancies, including SCCHN. This article focuses on the major molecular pathways implicated in SCCHN carcinogenesis and provides an overview of their therapeutic implications.

Targeting epidermal growth factor receptor in head and neck cancer: lessons learned from cetuximab

As early detection strategies have not been successful, most patients with head and neck cancer (HNC) present with advanced (stages III and IV) disease. Oral cavity tumors are treated primarily with surgical resection and advanced tumors of the pharynx and larynx are generally treated with combined modality therapy (chemoradiation). The major advances in the management of HNC have evolved from the integration of targeted therapeutics into treatment regimens. Presently, the most important target for new therapeutic strategies in HNC is the epidermal growth factor receptor (EGFR) and so far only cetuximab, a monoclonal antibody targeting EGFR, has been approved by the United States Food and Drug Administration in the HNC population as a radiation-sensitizing agent for patients undergoing primary radiation-based treatment and for patients with recurrent or metastatic disease. Other receptor and non-receptor kinase targeting strategies are under active clinical investigation as well. The increasing number of molecular targeting strategies in clinical development underscores the need to identify which HNC patients will respond to specific therapies. This article focuses on the current preclinical and clinical evidence of monoclonal antibodies targeting EGFR in HNC. We will first review the mechanisms of action of cetuximab, its clinical trials and side-effect profiles, and its present clinical application. Then, the current development status of other molecular antibodies and two molecular inhibitors, gefitinib and erlotinib, will be examined. Finally, by focusing on cetuximab, the current issues in EGFR targeting will be reviewed and we propose future directions of EGFR targeting. We hope that this review will provide further insight into the future directions of targeted therapy in the management of advanced HNC.

A review on the treatment of relapsed/metastatic head and neck cancer

The efficacy of traditional chemotherapy in inducing objective responses and prolonging survival in recurrent or metastatic head and neck cancer has been disappointing. More recent drugs have not proven superior to the classic regimen of cisplatin and 5-fluorouracil. Anti-EGFR monoclonal antibodies, either as single agents or associated to chemotherapy, have been shown to be active and little toxic. Among them, cetuximab has proven to be the most promising. Indeed the Extreme study, which compared the classic couple cisplatin (CDDP) + 5-fluorouracil with the same regimen plus cetuximab, has constituted a remarkable innovation. The results of that trial seem to indicate a third agent added to CDDP and 5-fluorouracil improved both progression-free survival and overall survival in the recurrent or metastatic setting. Unfortunately, the results obtained with the tyrosine kinase inhibitors are less impressive, and additional studies are needed to explore the potentiality of this class of drug. As far as antiangiogenetics are concerned, the research is insufficient for any conclusion to be drawn in terms of efficacy. It is hoped that, in the near future, the most active combination between biological agents and traditional chemotherapy will be found, so that the path successfully taken in other neoplastic diseases may be retraced.

Phase II Study of Sunitinib in Recurrent or Metastatic Squamous Cell Carcinoma of the Head and Neck: GORTEC 2006-01

Purpose

To assess the efficacy and toxicity of sunitinib monotherapy in palliative squamous cell carcinoma of the head and neck (SCCHN).

Patients and Methods

Thirty-eight patients with SCCHN having evidence of progressive disease (PD) were treated with sunitinib 37.5 mg/d given continuously until PD or unacceptable toxicity. The primary end point was the rate of disease control, defined as stable disease (SD) or partial response (PR) at 6 to 8 weeks after treatment initiation (two-stage design, Simon). Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) was performed in a subset of patients before and 6 to 8 weeks after treatment. The volume transfer constant of the contrast agent (Ktrans) was used to measure changes in the microcirculation blood flow and endothelial permeability of the tumor.

Results

A PR was observed in one patient, SD in 18, and PD in 19 (Response Evaluation Criteria in Solid Tumors [RECIST]), resulting in a disease control rate of 50%. Among the 18 patients with SD, there were five unconfirmed PRs and six additional minor responses. A significant decrease in Ktranswas seen in three of the four patients who received DCE-MRI monitoring. Grade 5 head and neck bleeds occurred in four patients. Local complications, including the appearance or worsening of tumor skin ulceration or tumor fistula, were recorded in 15 patients.

Conclusion

Sunitinib demonstrated modest activity in palliative SSCHN. The severity of some of the complications highlights the importance of improved patient selection for future studies with sunitinib in head and neck cancer. Sunitinib should not be used outside clinical trials in SSCHN.

Factors associated with clinical benefit from epidermal growth factor receptor inhibitors in recurrent and metastatic squamous cell carcinoma of the head and neck

Single agent epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKI) have demonstrated reproducible response rates of 5-15% in treatment of squamous cell carcinomas of the head and neck (SCCHN). The subset of patients that benefits most from these agents remains unknown. We reviewed individual patient data from five clinical trials of erlotinib, lapatinib, or gefitinib to determine if there are clinical characteristics that are associated with clinical benefit defined as complete response (CR), partial response (PR), and stable disease (SD) >4months. Secondary endpoints included progression-free survival (PFS) and overall survival (OS). Three-hundred and nineteen subjects were included. Observed responses were: 1% CR, 6% PR, 24% SD >4months, 18% SD <4months, 45% progressive disease (PD), 7% not evaluable (NE). The median OS was 6.4months and the median PFS was 2.7months. The most common toxicities observed were rash (grade 1 in 37%, grade 2 in 33%, grade 3+ in 6%) and diarrhea (grade 1 in 30%, grade 2 in 10%, grade 3+ in 5%). Performance status (PS) (p=0.04), older age (p=0.02), and development of rash (p<0.01), diarrhea (p=0.03), or oral side effects (p=0.02) were independently associated with clinical benefit. Older age, better PS, and development of rash were associated with longer PFS and OS. Clinical parameters that appear to predict response to EGFR TKI include PS and age. EGFR mechanistic toxicities that develop during therapy are also highly associated with benefit and suggest a relationship between drug exposure and outcome.

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.

Phase I study of lapatinib in combination with chemoradiation in patients with locally advanced squamous cell carcinoma of the head and neck

PURPOSE

This study (EGF100262) sought to establish the recommended phase II dose of lapatinib with chemoradiotherapy in patients with locally advanced squamous cell carcinoma of the head and neck (LA SCCHN).

PATIENTS AND METHODS

Patients were enrolled onto cohorts of escalating lapatinib dose (500, 1,000, and 1,500 mg/d). Patients received 1 week of lapatinib alone followed by 6.5 to 7 weeks of the same dose of lapatinib plus radiotherapy 66 to 70 Gy and cisplatin 100 mg/m(2) on days 1, 22, and 43 of radiotherapy. End points included safety/tolerability and clinical activity.

RESULTS

Thirty-one patients were enrolled (seven patients in each of the 500- and 1,000-mg cohorts and three in the 1,500-mg cohort; an additional 14 patients were enrolled at 1,500 mg in a safety cohort). Dose-limiting toxicities (DLTs) included perforated ulcer in one patient in the 500-mg cohort and transient elevation of liver enzymes in one patient in the 1,000-mg cohort. No DLTs were observed in the 1,500-mg cohort. Therefore, the recommended phase II dose was defined as lapatinib 1,500 mg/d with chemoradiotherapy. The most common grade 3 to 4 adverse events were radiation mucositis, radiation dermatitis, lymphopenia, and neutropenia. No patients experienced drug-related symptomatic cardiotoxicity, and no interstitial pneumonitis was reported. The overall response rate was 81% (65% at the recommended phase II dose).

CONCLUSION

The recommended phase II dose is lapatinib 1,500 mg/d with chemoradiotherapy in patients with LA SCCHN; this regimen is associated with an acceptable tolerability profile. Given these findings, randomized phase II and III studies of lapatinib plus chemoradiotherapy have been initiated.

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.

Emerging perspectives in epidermal growth factor receptor targeting in head and neck cancer

The epidermal growth factor receptor (EGFR) has been shown to be a promising therapeutic target in head and neck cancer. Cetuximab, a monoclonal antibody against EGFR, has been approved in the United States for use with radiotherapy for head and neck squamous cell carcinoma. However, the role of EGFR targeting agents in other therapeutic modalities, such as combined chemoradiotherapy or induction chemotherapy, remains to be defined. Although results from several clinical trials have demonstrated the therapeutic potentials of EGFR targeting agents in these settings, further studies are necessary before definitive conclusions can be made. The concurrent targeting of EGFR along with other pathways important in carcinogenesis may hold significant therapeutic potential. In particular, several clinical trials are studying the effects of combining agents that target the vascular endothelial growth factor with EGFR inhibitors. Last, studies are ongoing to elucidate the predictive and correlative biomarkers in anti-EGFR therapy to allow for proper patient selection. In the case of cetuximab, these correlative biomarkers may include elements of the immune system in addition to the signal transduction proteins involved in EGFR pathway.

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.

Activity of lapatinib is independent of EGFR expression level in HER2-overexpressing breast cancer cells

Epidermal growth factor receptor (EGFR/ErbB1) and HER2 (ErbB2/neu), members of the ErbB receptor tyrosine kinase family, are frequently overexpressed in breast cancer and are known to drive tumor growth and progression, making them promising targets for cancer therapy. Lapatinib is a selective competitive inhibitor of both the HER2 and EGFR tyrosine kinases. Although lapatinib showed significant activity in patients with HER2-positive breast cancer, the role of EGFR in the response of breast cancer to lapatinib has not been defined. Here, we examined the role of EGFR expression levels in the sensitivity of HER2-overexpressing breast cancer cells to lapatinib. Depletion of EGFR by EGFR small-interfering RNA knockdown did not affect lapatinib sensitivity in these cells, whereas treated HER2 siRNA knockdown cells became more resistant to lapatinib. We conclude that the in vitro activity of lapatinib is not dependent on EGFR expression level in HER2-overexpressing breast cancer cells.

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.

Molecular targeted therapy of head and neck cancer: Review and clinical development challenges

Recently, new targets have been identified in head and neck squamous cell carcinomas (HNSCC) as playing key roles in tumour proliferation and metastases. The first target that has led to the approval of a molecularly based therapy in HNSCC has been the epidermal growth factor receptor (EGFR). Indeed, cetuximab, a monoclonal antibody directed against EGFR, has recently been approved in combination with radiation therapy in patients with locally advanced HNSCC, and in patients with platinum-refractory recurrent or metastatic (R/M) HNSCC. This review discusses novel targeted anticancer agents that do not exclusively target EGFR. The initial assessments of novel agents have typically been in patients with heavily pre-treated R/M HNSCC, with response rates and times to progression that are often disappointing. Evaluation of novel agents in the pre-operative 'window' setting, or as first-line therapy for R/M disease, may offer a more optimal understanding of their molecular and clinical effects.

Lapatinib: a tyrosine kinase inhibitor with a clinical role in breast cancer

Lapatinib is a dual (ErbB-1 and ErB-2) receptor tyrosine kinase inhibitor (TKI) that was recently approved by the FDA for the treatment of advanced breast cancer. It shows synergy with trastuzumab, and has demonstrated clinical activity in trastuzumab-resistant tumour. This paper reviews the drug development of lapatinib from preclinical studies to the pivotal Phase III trial and ongoing clinical studies. Areas of interest include the advantages of small molecule TKIs versus antibodies in targeting HER receptors and the efficacy of lapatinib in the treatment of cerebral metastases. The surprisingly high response rate in inflammatory breast cancer raises the possibility of other novel predictive biomarkers. The potential for combination and sequencing with other biological and cytotoxic agents is both exciting and challenging.

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.

Malignancies of the head and neck: the role for molecular targeted agents

Although cancers arising in the head and neck region are a diverse group of malignancies, a unifying thread remains a poor overall survival for patients with advanced, recurrent or metastatic disease. Treatment strategies need to evolve and improve upon established therapeutic practices. As the process of cancer evolution is understood to be derived from aberrations in genetic and epigenetic processes, molecularly targeted agents offer attractive therapeutic options by restoring normal control of oncogenic processes. The direct role for the treatment of squamous cell carcinoma of the head and neck, nasopharynx and salivary gland carcinomas with these novel, molecularly targeted agents are reviewed and their potential to improve on the existing standard of care is further explored.

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.

Dual inhibition of ErbB1 (EGFR/HER1) and ErbB2 (HER2/neu)

Targeting of epidermal growth factor receptor (EGFR) and HER2 is a proven anti-cancer strategy. However, heterodimerisation, compensatory 'crosstalk' and redundancy exist in the ErbB network, and there is therefore a sound scientific rationale for dual inhibition of EGFR and HER2. Trials of approved agents in combination, for example trastuzumab and cetuximab, are underway. There is also a new generation of small molecule tyrosine kinase inhibitors (TKIs) and monoclonal antibodies (mABs) that target two or more ErbB receptors. Lapatinib, a TKI of EGFR and HER2, has shown clinical benefit in trastuzumab refractory breast cancer and is poised for FDA approval. Other agents include BIBW-2992 and HKI-272, irreversible TKIs of EGFR and HER2, and pertuzumab, a heterodimerisation inhibitor of EGFR and HER2.

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.

Emerging drugs for head and neck cancer

Head and neck cancer is a challenging disease. The treatment is quite complex and significant toxicity is seen with the combination of chemotherapy, radiation therapy and surgery. The present standard of care is chemoradiotherapy for most sites in the head and neck area for patients with locally advanced, unresectable disease and in patients treated for organ preservation. The recent approval of cetuximab, an EGF receptor inhibitor, for head and neck cancer in combination with radiotherapy represent an opportunity to improve the outcome for these patients, and the inclusion of this antibody within the chemoradiotherapy approaches will be studied in Phase III trials. In addition, a significant shift is occurring with the inclusion of more aggressive chemotherapy upfront, prior to chemoradiotherapy. This approach, known as sequential chemoradiotherapy, is the basis of many recently completed Phase III trials. Docetaxel, cisplatin and 5-fluorouracil appears to be the most effective induction chemotherapy regimen and is the new induction 'standard' that is being used by many cancer centres and intergroups going forward. It is also a new platform that will be used to add new targeted agents to induction chemotherapy.

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.