Interventions for the treatment of oral and oropharyngeal cancers: targeted therapy and immunotherapy

BACKGROUND

Oral cancers are the sixth most common cancer worldwide, yet the prognosis following a diagnosis of oral cavity or oropharyngeal cancers remains poor, with approximately 50% survival at five years. Despite a sharp increase in research into molecularly targeted therapies and a rapid expansion in the number of clinical trials assessing new targeted therapies, their value for treating oral cancers is unclear. Therefore, it is important to summarise the evidence to determine the efficacy and toxicity of targeted therapies and immunotherapies for the treatment of these cancers.

OBJECTIVES

To assess the effects of molecularly targeted therapies and immunotherapies, in addition to standard therapies, for the treatment of oral cavity or oropharyngeal cancers.

SEARCH METHODS

We searched the following electronic databases: Cochrane Oral Health Group Trials Register (to 3 February 2015), Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, 2015, Issue 1), MEDLINE via Ovid (1946 to 3 February 2015) and EMBASE via Ovid (1980 to 3 February 2015). We searched the US National Institutes of Health Trials Register (clinicaltrials.gov), the World Health Organization Clinical Trials Registry Platform, the American Society of Clinical Oncology conference abstracts and the Radiation Therapy Oncology Group clinical trials protocols for ongoing trials. We placed no restrictions on the language or date of publication.

SELECTION CRITERIA

We included randomised controlled trials where more than 50% of participants had primary tumours of the oral cavity or oropharynx, and which compared targeted therapy or immunotherapy, plus standard therapy, with standard therapy alone.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the results of the electronic searches, extracted data and assessed the risk of bias of the included studies. We attempted to contact study authors for missing data or clarification where necessary. We combined sufficiently similar studies in meta-analyses using random-effects models when there were at least four studies and fixed-effect models when fewer than four studies. We obtained or calculated a hazard ratio (HR) and 95% confidence interval (CI) for the primary outcomes where possible. For dichotomous outcomes, we reported risk ratios (RR) and 95% CIs.

MAIN RESULTS

Twelve trials (2488 participants) satisfied the inclusion criteria. In the included trials, 12% of participants (298 participants) had tumours of the oral cavity and 59% (1468 participants) had oropharyngeal tumours. The remaining 29% had tumours of the larynx or hypopharynx and less than 1% had tumours at other sites.No included trial was at low risk of bias; seven had an unclear risk of bias, and five had a high risk of bias. We grouped trials by intervention type into three main comparisons: standard therapy plus epidermal growth factor receptor monoclonal antibody (EGFR mAb) therapy (follow-up period 24 to 70 months); standard therapy plus tyrosine kinase inhibitors (TKIs) (follow-up period 40 to 60 months) and standard therapy plus immunotherapy (follow-up period 24 to 70 months), all versus standard therapy alone.Moderate quality evidence showed that EGFR mAb therapy may result in 18% fewer deaths when added to standard therapy (HR of mortality 0.82; 95% CI 0.69 to 0.97; 1421 participants, three studies, 67% oropharyngeal tumours, 2% oral cavity tumours).There was also moderate quality evidence that EGFR mAb may result in 32% fewer locoregional failures when added to radiotherapy (RT) (HR 0.68; 95% CI 0.52 to 0.89; 424 participants, one study, 60% oropharyngeal tumours).A subgroup analysis separating studies by type of standard therapy (radiotherapy (RT) or chemoradiotherapy (CRT)) showed some evidence that adding EGFR mAb therapy to RT may result in a 30% reduction in the number of people whose disease progresses (HR 0.70; 95% CI 0.54 to 0.91; 424 participants, one study, 60% oropharyngeal tumours, unclear risk of bias). For the subgroup comparing EGFR mAb plus CRT with CRT alone there was insufficient evidence to determine whether adding EGFR mAb therapy to CRT impacts on progression-free survival (HR 1.08; 95% CI 0.89 to 1.32; 891 participants, one study, 70% oropharyngeal tumours, high risk of bias). The high subgroup heterogeneity meant that we were unable to pool these subgroups.There was evidence that adding cetuximab to standard therapy may result in increased skin toxicity and rash (RR 6.56; 95% CI 5.35 to 8.03; 1311 participants, two studies), but insufficient evidence to determine any difference in skin toxicity and rash in the case of nimotuzumab (RR 1.06; 95% CI 0.85 to 1.31; 92 participants, one study).There was insufficient evidence to determine whether TKIs added to standard therapy impacts on overall survival (HR 0.99; 95% CI 0.62 to 1.57; 271 participants, two studies; very low quality evidence), locoregional control (HR 0.89; 95% CI 0.53 to 1.49; 271 participants, two studies; very low quality evidence), disease-free survival (HR 1.51; 95% CI 0.61 to 3.71; 60 participants, one study; very low quality evidence) or progression-free survival (HR 0.80; 95% CI 0.51 to 1.28; 271 participants, two studies; very low quality evidence). We did find evidence of an increase in skin rash (erlotinib: RR 6.57; 95% CI 3.60 to 12.00; 191 participants, one study; lapatinib: RR 2.02; 95% CI 1.23 to 3.32; 67 participants, one study) and gastrointestinal complaints (lapatinib: RR 15.53; 95% CI 2.18 to 110.55; 67 participants, one study).We found very low quality evidence from one small trial that adding recombinant interleukin (rIL-2) to surgery may increase overall survival (HR 0.52; 95% CI 0.31 to 0.87; 201 participants, 62% oral cavity tumours, 38% oropharyngeal tumours) and there was insufficient evidence to determine whether rIL-2 impacts on adverse effects.

AUTHORS' CONCLUSIONS

We found some evidence that adding EGFR mAb to standard therapy may increase overall survival, progression-free survival and locoregional control, while resulting in an increase in skin toxicity for some mAb (cetuximab).There is insufficient evidence to determine whether adding TKIs to standard therapies changes any of our primary outcomes.Very low quality evidence from a single study suggests that rIL-2 combined with surgery may increase overall survival compared with surgery alone.

Systemic delivery of E6/7 siRNA using novel lipidic particles and its application with cisplatin in cervical cancer mouse models

Small interfering RNA (siRNA) shows great promise in cancer therapy, but its effectiveness in vivo still remains a crucial issue for its transition into the clinics. Although the successful use of polyethylene glycol (PEG)ylated lipidic delivery systems have already been reported, most of the formulation procedures used are labour intensive and also result in unstable end products. We have previously developed a simple yet efficient hydration-of-freeze-dried-matrix (HFDM) method to entrap siRNA within lipid particles, in which the products exhibited superior stability. Here, we show that these HFDM-formulated particles are stable in the presence of serum and can deliver siRNA efficiently to tumours after intravenous administration. Using these particles, around 50% knockdown of the target gene expression was observed in tumours. With the use of siRNA targeting the E6/7 oncogenes expressed in cervical cancer, we showed a 50% reduction in tumour size. This level of tumour growth suppression was comparable to that achieved from cisplatin at the clinically used dose. Overall, our results demonstrate the feasibility of using HFDM-formulated particles to systematically administer E6/7-targeted siRNA for cervical cancer treatment. The simplicity of preparation procedure along with superior product stability obtained from our method offers an innovative approach for the in vivo delivery of siRNA.

Emerging applications of stereotactic radiotherapy in head and neck cancer

Advances in the management of locally advanced head and neck cancer (HNC) have been focused on treatment intensification, including concomitant chemoradiotherapy, biological agents, and combining surgery with chemoradiotherapy. Despite these improvements, locoregional recurrence still constitutes the main pattern of treatment failure. As improvements in radiotherapy delivery and image-guided therapy have come to fruition, the principles of stereotactic radiosurgery are now being applied to extracranial sites, leading to stereotactic body radiotherapy. This article focuses on the emerging evidence for the use of stereotactic body radiotherapy for treatment of HNC as a boost after conventional external-beam radiotherapy, and also as reirradiation in recurrent or second primary HNC.

Antitumor mechanisms of combined gastrin-releasing peptide receptor and epidermal growth factor receptor targeting in head and neck cancer

Head and neck squamous cell carcinoma (HNSCC) is characterized by epidermal growth factor receptor (EGFR) overexpression, where EGFR levels correlate with survival. To date, EGFR targeting has shown limited antitumor effects in head and neck cancer when administrated as monotherapy. We previously identified a gastrin-releasing peptide/gastrin-releasing peptide receptor (GRP/GRPR) aurocrine regulatory pathway in HNSCC, where GRP stimulates Src-dependent cleavage of EGFR proligands with subsequent EGFR phosphorylation and mitogen-activated protein kinase (MAPK) activation. To determine whether GRPR targeting can enhance the antitumor efficacy of EGFR inhibition, we investigated the effects of a GRPR antagonist (PD176252) in conjunction with an EGFR tyrosine kinase inhibitor (erlotinib). Combined blockade of GRPR and EGFR pathways significantly inhibited HNSCC, but not immortalized mucosal epithelial cell, proliferation, invasion, and colony formation. In addition, the percentage of apoptotic cells increased upon combined inhibition. The enhanced antitumor efficacy was accompanied by increased expression of cleaved poly(ADP-ribose) polymerase (PARP) and decreased phospho-EGFR, phospho-MAPK, and proliferating cell nuclear antigen (PCNA). Using reverse-phase protein microarray (RPPA), we further detected decreased expression of phospho-c-Jun, phospho-p70S6K, and phospho-p38 with combined targeting. Cumulatively, these results suggest that GRPR targeting can enhance the antitumor effects of EGFR inhibitors in head and neck cancer.

Epidermal growth factor receptor tyrosine kinase inhibitor, erlotinib, and concurrent 5-fluorouracil, cisplatin and radiotherapy for patients with esophageal cancer: a phase I study

This phase I trial investigates the safety of combining radiation, 5-fluorouracil (5-FU) and cisplatin with the epidermal growth factor receptor tyrosine kinase inhibitor, erlotinib, in patients with esophageal carcinoma. From April 2000 to January 2005, 11 patients with squamous or adenocarcinoma of the esophagus were enrolled. Patients received either 50, 100 or 150 mg oral erlotinib/day beginning on the first day of radiation (three patients in each dose cohort). Concurrent cisplatin (75 mg/m2 i.v., days 8 and 36) and 5-FU (1000 mg/m2 i.v., days 8-11 and 36-39) were also given with 50.4 Gy thoracic radiation, delivered at 180 cGy/day, 5 days/week. Toxicity was evaluated using the National Cancer Institute Common Toxicity Criteria (version 3.0). Erlotinib with concurrent 5-FU, cisplatin and thoracic radiation was well-tolerated at 50, 100 and 150 mg/day. The major toxicities were diarrhea (grade 1=18%, grade 2=18%), skin rash (grade 4=54.5%), nausea (grade 1=18%, grade 2=54%, grade 3=9%) and dehydration (grade 3=27%). All patients experienced esophagitis during treatment (grade 1=55%, grade 2=32%, grade 3=9%, grade 4=9%). Two patients were discontinued from the study secondary to non-erlotinib-related toxicities. We conclude that the phase I study demonstrates the safety and tolerability of erlotinib delivered at 150 mg/day with concurrent 5-FU, cisplatin and thoracic radiation. The major toxicities encountered were grade 1-2 diarrhea, grade 1 skin rash, grade 1-3 nausea and grade 3 dehydration. A phase II study is planned.

Clinical implications of EGFR expression in the development and progression of solid tumors: focus on non-small cell lung cancer

Dysregulation of the epidermal growth factor receptor (EGFR) signaling pathway is associated with the development and progression of malignancy, and EGFR-targeted therapies offer the promise of better treatment for many types of solid tumors, including non-small cell lung cancer. Anti-EGFR agents include monoclonal antibodies (mAbs) targeting the EGFR extracellular receptor domain and small-molecule tyrosine kinase inhibitors (TKIs) targeting the EGFR intracellular kinase domain. Both mAbs and TKIs have demonstrated encouraging results as monotherapies and in combination with chemotherapy and radiotherapy. This review provides a critical update on the status of these novel therapeutics.

The evolving role of cetuximab in non-small cell lung cancer

Cetuximab is a monoclonal antibody directed against the ligand binding site in the extracellular domain of the epidermal growth factor receptor (EGFR). Cetuximab is currently approved for the treatment of patients with refractory colorectal cancer. In locally advanced head and neck carcinoma, cetuximab in combination with radiotherapy significantly improved survival compared with radiotherapy alone, and this treatment awaits Food and Drug Administration approval. In previously treated non-small cell lung cancer, single-agent cetuximab produced an objective response in 3 of 66 eligible patients and a median survival of 8.1 months. Treatment was well tolerated, with skin rash as the principal toxicity. The vast majority of patients (60 of 66) expressed EGFR by immunohistochemistry but no correlation existed between response and EGFR mutations. Two single-arm phase II trials testing cetuximab in combination with a platinum-based doublet in previously untreated patients showed responses in the range of 26% to 29%, with median survival times of 10 to 11 months. A European phase II randomized trial tested cisplatin/vinorelbine with or without cetuximab as first-line therapy in 86 patients with advanced non-small-cell lung cancer. Overall efficacy was slightly superior in the cetuximab arm and a phase III trial is currently ongoing to definitively determine the role of cetuximab in this setting.

Use of an orthotopic xenograft model for assessing the effect of epidermal growth factor receptor amplification on glioblastoma radiation response

PURPOSE

The influence of epidermal growth factor receptor (EGFR) amplification on glioblastoma patient prognosis following definitive radiotherapy has been extensively investigated in clinical studies, and yet the relationship between EGFR status and radiation response remains unclear. The intent of the current study was to address this relationship using several EGFR-amplified glioblastoma xenografts in an orthotopic athymic mouse model.

EXPERIMENTAL DESIGN

We examined the effect of radiation on the survival of nude mice with intracranial xenografts derived from 13 distinct patient tumors, 7 of which have amplified EGFR. Mice with established intracranial tumors were randomized to sham treatment or 12-Gy radiation in six fractions delivered over 12 days.

RESULTS

For six of the xenografts, radiation of mice with intracranial tumor significantly extended survival, and four of these xenografts had EGFR amplification. For seven other xenografts, radiation treatment did not significantly extend survival, and three of these, including GBM12, had EGFR amplification. Similar to EGFR, the tumor genetic status of p53 or PTEN did not show preferential association with radiation-sensitive or radiation-resistant xenografts whereas hyperphosphorylation of Akt on Ser(473) was associated with increased radioresistance. To specifically investigate whether inhibition of EGFR kinase activity influences radiation response, we examined combined radiation and EGFR inhibitor treatment in mice with intracranial GBM12. The combination of oral erlotinib administered concurrently with radiation resulted only in additive survival benefit relative to either agent alone.

CONCLUSIONS

Our results indicate that EGFR amplification, as a biomarker, is not singularly predictive of glioblastoma response to radiation therapy, nor does the inhibition of EGFR enhance the intrinsic radiation responsiveness of glioblastoma tumors. However, efficacious EGFR inhibitor and radiation monotherapy regimens can be used in combination to achieve additive antitumor effect against a subset of glioblastoma.

Targeting growth factors and angiogenesis; using small molecules in malignancy

Targeted biologic therapy for cancer has evolved from the laboratory to active clinical protocols and applied clinical practice in selected patients. Major targets include epidermal growth factor, and vascular endothelial growth factor receptors which are commonly expressed in gastro-intestinal cancers head & neck and lung cancers, and to some degree breast and gynecologic malignancy. Down stream signal transduction pathway inhibition of B-raf and N-ras mutations are examined in melanoma. New approaches involving re-packaging of chemotherapeutic agents are being exemplified in the nanoparticle formulation of paclitaxel which provides increased access to endothelial and tumor cells with potential enhanced therapeutic efficacy compared to the conventional version solubilized in a cremophor.

Phase I/II study of cetuximab in combination with cisplatin or carboplatin and fluorouracil in patients with recurrent or metastatic squamous cell carcinoma of the head and neck

PURPOSE

This was an open, randomized, multicenter, phase I/II study to investigate the safety and tolerability of cetuximab in the first-line treatment of recurrent/metastatic squamous cell carcinoma of the head and neck (SCCHN).

PATIENTS AND METHODS

Treatment comprised cetuximab (initial dose 400 mg/m2 with subsequent weekly doses of 250 mg/m2) in combination with 3-week cycles of either cisplatin (100 mg/m2) or carboplatin (area under the curve, 5), each in combination with a 5-day infusion of fluorouracil (FU) at escalating doses of 600, 800, and 1,000 mg/m2/d. The study was divided into two phases: A, the first two cycles (6 weeks) focusing on the safety and tolerability of combination therapy; and B, the remaining time for those benefiting from therapy until disease progression or intolerable toxicity.

RESULTS

Fifty-three patients were enrolled onto the study. The incidence of dose-limiting toxicities in phase A was acceptable. The most common grade 3/4 adverse events in both groups were leucopenia (38%), asthenia (25%), vomiting (14%), and thrombocytopenia (15%), which are consistent with the known safety profiles of cetuximab, cisplatin/carboplatin, and FU. The overall response rate among patients was 36%, with no clear trend toward an increased efficacy at the highest dose of FU, and no impact of the concomitant chemotherapy regimens on cetuximab pharmacokinetics.

CONCLUSION

The combination of cetuximab, cisplatin/carboplatin, and FU was reasonably well tolerated and active in recurrent/metastatic SCCHN, and merits additional investigation. An FU dose of 1,000 mg/m2/d in combination with cisplatin or carboplatin can be recommended for additional studies.

Interaction of the epidermal growth factor receptor and the DNA-dependent protein kinase pathway following gefitinib treatment

The epidermal growth factor receptor (EGFR) is an important target for cancer therapy. We previously showed that the EGFR inhibitor gefitinib modulated repair of DNA damage following exposure to cisplatin and etoposide involving the DNA-dependent protein kinase (DNA-PK) pathway. In this study, we specifically investigated the effect of EGFR inhibition by gefitinib on functional activity of DNA-PK in cancer cell lines and the interaction between EGFR and DNA-PK. The effects of DNA-PK inhibition by wortmannin and small interfering RNA to the catalytic subunit of DNA-PK (DNA-PK(CS)) on cell proliferation and DNA interstrand cross-link repair were investigated in the human MCF-7 breast cancer cell line and compared with the effects of gefitinib. DNA-PK activity was quantitated and expression measured by immunoblotting following gefitinib treatment. Immunoprecipitation experiments were done with and without gefitinib in MCF-7 cells, the AR42J pancreas cell line with high EGFR, and the human MDA-453 breast cancer cell line expressing low EGFR. Nuclear and cytoplasmic extracts were immunoblotted with antibody to DNA-PK(CS) to determine if gefitinib treatment altered cellular expression. Reduction of DNA-PK activity by wortmannin and expression by small interfering RNA to DNA-PK(CS) sensitized cells to cisplatin and inhibited repair of cisplatin-induced interstrand cross-links. Gefitinib treatment reduced DNA-PK activity in MCF-7 and AR42J but not MDA-453 cells. Immunoprecipitation experiments showed interaction between EGFR and DNA-PK(CS) in a dose-dependent and time-dependent manner following gefitinib treatment in MCF-7 and AR42J but not MDA-453 cells. Gefitinib treatment reduced nuclear expression and increased cytosolic expression of DNA-PK(CS) in MCF-7 and AR42J but not MDA-453 cells. Treatment with gefitinib modulates association of EGFR and DNA-PK(CS). This is correlated with decreased function of DNA-PK(CS). Inhibition of DNA-PK(CS) may be an important factor in sensitization to chemotherapy and radiation following treatment with inhibitors of the EGFR pathway.

Radiotherapy for head and neck cancer: latest developments and future perspectives

PURPOSE OF REVIEW

Despite recent advances in multimodality management the prognosis of patients with stage III-IV squamous cell head and neck cancer remains disappointing. The objective of this review is to identify how, within the main axes of the current translational and clinical research and in an attempt to improve treatment outcome, a number of institutions and cooperative groups have embarked on systematic investigations of novel strategies for radiotherapy delivery and for combining radiation with systemic treatments.

RECENT FINDINGS

Four domains of translational and clinical researches can be identified in head and neck radio-oncology: altered fractionation, concurrent delivery of chemotherapy and radiotherapy, combination of targeted therapies with radiation, and high-conformality radiotherapy.

SUMMARY

Here we provide a critical appraisal of recent strategies allowing an increase in dose intensity for treatments based on radiotherapy and drug-radiation interactions, and revisit the potential opportunities they offer as well as the possible caveats they may present in patients with locally advanced head and neck cancers.

Chemoradiation paradigm for the treatment of lung cancer

For the treatment of locoregional advanced stage III non-small-cell lung cancer, when chemotherapy is added sequentially to radiotherapy it acts systemically and is aimed at reducing distant metastases. Concurrent chemotherapy and radiation, however, is intended to enhance the locoregional efficacy of this modality. Combined effects of these modalities are based on their different toxicity profiles, leading to a reduced toxicity : efficacy ratio of the combination. Controlled trials investigating this additive approach indicate that concurrent application of chemotherapy and radiotherapy results in a small but significant benefit for locoregional control, which translates into a small but measurable survival benefit. This benefit is most evident when looking at 3-year or 5-year overall survival rates, when it is of clinical significance. The use of single-agent cisplatin has already demonstrated major radiosensitizing effects whereas the radiosensitizing properties of concurrent application of the single-agent carboplatin have not been observed in controlled trials. Newer drugs such as vinorelbine, the taxanes and gemcitabine might enhance this effect, although no improvement has been observed in randomized controlled trials comparing such regimens with single-agent cisplatin. New 'targeted' agents might synergize with ionizing irradiation and provide an interesting rationale concerning combined modality therapy, but this hypothesis awaits prospective clinical evidence from randomized controlled trials.

Recent new approaches to the treatment of head and neck cancer

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer in the world and affects 50,000 Americans annually. During the past 20 years, treatments for HNSCC have changed dramatically due largely to the advent of novel approaches such as combined modality therapy, as well as improvements in surgical and radiotherapeutic techniques. Ongoing advances in the multidisciplinary management of this complex and multivariate disease process are resulting in improved function, quality of life and survival. Here, we review state-of-the-art therapy and presents selected advances in the treatment of head and neck cancer.

Concurrent cetuximab, cisplatin, and concomitant boost radiotherapy for locoregionally advanced, squamous cell head and neck cancer: a pilot phase II study of a new combined-modality paradigm

PURPOSE

Cetuximab is a chimeric monoclonal antibody that targets the epidermal growth factor receptor. Cetuximab has activity in squamous cell carcinoma and enhances both chemotherapy and radiotherapy. We conducted a pilot phase II study of a new combined-modality paradigm of targeted therapy (cetuximab) with chemoradiotherapy.

PATIENTS AND METHODS

Eligible patients had stage III or IV, M0, squamous cell head and neck cancer. Treatment included concomitant boost radiotherapy (1.8 Gy/d weeks 1 to 6; boost: 1.6 Gy 4 to 6 hours later weeks 5 to 6; 70 Gy total to gross disease), cisplatin (100 mg/m2 intravenously weeks 1 and 4), and cetuximab (400 mg/m2 intravenously week 1, followed by 250 mg/m2 weeks 2 to 10).

RESULTS

Twenty-two patients were enrolled (median age, 57 years; range, 41 to 72 years; median Karnofsky status, 90%; range, 70% to 90%; oropharynx primary tumor, 59% of patients; T4, 36%; N2/3, 77%; stage IV disease, 86%). One patient did not receive study treatment because of an ineligible diagnosis. The severity of expected, acute toxicities was typical of concurrent cisplatin and radiotherapy alone. Grade 3 or 4 cetuximab-related toxicities included acne-like rash (10%) and hypersensitivity (5%). However, the study was closed for significant adverse events, including two deaths (one pneumonia and one unknown cause), one myocardial infarction, one bacteremia, and one atrial fibrillation. With a median follow-up of 52 months, the 3-year overall survival rate is 76%, the 3-year progression-free survival rate is 56%, and the 3-year locoregional control rate is 71%.

CONCLUSION

This regimen is not currently recommended outside of the clinical trial setting. Further investigation of its safety profile is needed. However, preliminary efficacy is encouraging, and further development of this targeted combined-modality paradigm is warranted.

Targeted therapies for esophageal cancer

Esophageal cancer is a highly aggressive neoplasm. In 2005, 14,520 Americans will be diagnosed with esophageal cancer, and more than 90% will die of their disease. On a global basis, cancer of the esophagus is the sixth leading cause of cancer death worldwide. In fact, gastric and esophageal cancers together accounted for nearly 1.3 million new cases and 980,000 deaths worldwide in 2000-more than lung, breast, or colorectal cancer. Although esophageal squamous cell carcinoma cases have steadily declined, the incidence of gastroesophageal junction adenocarcinoma has increased 4%-10% per year among U.S. men since 1976, more rapidly than for any other cancer type, and parallels rises in population trends in obesity and reflux disease. With advances in surgical techniques and treatment, the prognosis of esophageal cancer has slowly improved over the past three decades. However, the 5-year overall survival rate (14%) remains poor, even in comparison with the dismal survival rates (4%) from the 1970s. The underlying reasons for this disappointingly low survival rate are multifold: (a) ineffective screening tools and guidelines; (b) cancer detection at an advanced stage, with over 50% of patients with unresectable disease or distant metastasis at presentation; (c) high risk for recurrent disease after esophagectomy or definitive chemoradiotherapy; (d) unreliable noninvasive tools to measure complete response to chemoradiotherapy; and (e) limited survival achieved with palliative chemotherapy alone for patients with metastatic or unresectable disease. Clearly, additional strategies are needed to detect esophageal cancer earlier and to improve our systemic treatment options. Over the past decade, the field of drug development has been transformed with the identification of and ability to direct treatment at specific molecular targets. This review focuses on novel targeted treatments in development for esophageal squamous cell carcinoma and distal esophageal and gastroesophageal junction adenocarcinoma.

Prognostic Value of an Activation State Marker for Epidermal Growth Factor Receptor in Tissue Microarrays of Head and Neck Cancer

Overexpression and mutation of epidermal growth factor receptors (EGFR) have been shown to be important in the prognosis of several cancers, including head and neck cancers. However, our inability to define the activation status of these and other receptors limits our ability to assess the importance of these pathways and to exploit effectively new molecularly targeted treatments directed at their catalytic activities. Here we describe the use of automated, high-throughput fluorescence lifetime imaging microscopy to measure EGFR autophosphorylation status by fluorescence resonance energy transfer (FRET) in head and neck tumors. We have correlated FRET efficiency with the clinical and survival data. The results from head and neck arrays show that high FRET efficiency is correlated with worsening disease-free survival but not with overall survival. This powerful tool could be exploited as a new independent quantitative prognostic factor in clinical decisions and cancer management.

Cetuximab and irinotecan interact synergistically to inhibit the growth of orthotopic anaplastic thyroid carcinoma xenografts in nude mice

PURPOSE

Anaplastic thyroid carcinoma (ATC) remains one of the most lethal known human cancers. Targeted molecular therapy with cetuximab, a monoclonal antibody against epidermal growth factor receptor, offers new treatment potentials for patient with ATC. Cetuximab has also been reported to have synergistic effects when combined with irinotecan, a topoisomerase inhibitor. Therefore, we hypothesized that cetuximab and irinotecan would be effective in inhibiting the growth and progression of ATC in a murine orthotopic model.

EXPERIMENTAL DESIGN

The in vitro antiproliferative effects of cetuximab and irinotecan on ATC cell line ARO were examined. We also studied the in vivo effects of cetuximab and irinotecan on the growth, invasion, and metastasis of orthotopic ATC tumors in nude mice. The in vivo antitumor efficacy of cetuximab/irinotecan combination was also compared with that of doxorubicin.

RESULTS

Cetuximab alone did not show any antiproliferative or proapoptotic effect on this cell line. However, when combined with irinotecan, cetuximab potentiated the in vitro antiproliferative and proapoptotic effect of irinotecan. Cetuximab, irinotecan, and cetuximab/irinotecan combination resulted in 77%, 79%, and 93% in vivo inhibition of tumor growth, respectively. Incidences of lymph node metastasis, laryngeal invasion, and tumor microvessel density were also significantly decreased in these treatment groups. Furthermore, the cetuximab/irinotecan combination was significantly more effective than doxorubicin in inhibiting the growth of orthotopic ATC xenografts.

CONCLUSIONS

Combination therapy with cetuximab/irinotecan inhibits the growth and progression of orthotopic ATC xenografts in nude mice. Given the lack of curative options for patients with ATC, combination therapy with cetuximab and irinotecan treatment warrants further study.

Synergistic effects of gemcitabine and gefitinib in the treatment of head and neck carcinoma

Although the combination of gemcitabine and radiation produces a high frequency of complete responses in the treatment of locally advanced head and neck cancer, substantial toxicity suggests that an improvement in the therapeutic index is required. The purpose of this study was to determine if gefitinib could improve the efficacy of gemcitabine and if drug schedule is important. We hypothesized that gemcitabine followed by gefitinib would be superior to the opposite order because of both cell cycle and growth factor signaling interactions. Using UMSCC-1 cells in vitro, we confirmed that gefitinib arrested cells in G(1) and suppressed phospho-epidermal growth factor receptor (p(Y845)EGFR) and that gemcitabine arrested cells in S phase and stimulated p(Y845)EGFR. The schedule of gemcitabine followed by gefitinib caused arrest of cells in S phase. Gefitinib suppressed gemcitabine-mediated p(Y845)EGFR stimulation. This schedule caused decreased p(S473)AKT, increased poly(ADP-ribose) polymerase cleavage, and increased apoptosis compared with gemcitabine alone. The schedule of gefitinib followed by gemcitabine also caused suppression of p(Y845)EGFR but arrested cells in G(1). This schedule in which gefitinib was used first was associated with stable levels of p(S473)AKT and minimal poly(ADP-ribose) polymerase cleavage and apoptosis. These results were reflected in experiments in nude mice bearing UMSCC-1 xenografts, in which there was greater tumor regression and apoptosis when animals received gemcitabine followed by gefitinib during the first week of therapy. These findings suggest that the schedule of gemcitabine followed by gefitinib may increase the therapeutic index over gemcitabine alone and, combined with clinical data, encourage exploration of combination of gemcitabine, EGFR inhibitors, and radiation.

Increased toxicity with gefitinib, capecitabine, and radiation therapy in pancreatic and rectal cancer: phase I trial results

PURPOSE

Overexpression of epidermal growth factor receptor (EGFR) has been associated with aggressive tumor phenotypes, chemotherapy, and radiation resistance, as well as poor survival in preclinical and clinical models. The EGFR inhibitor gefitinib potentiates chemotherapy and radiation tumor cytotoxicity in preclinical models, including pancreatic and colorectal cancer. We initiated two phase I trials assessing the combination of gefitinib, capecitabine, and radiation in patients with localized pancreatic and rectal cancer.

PATIENTS AND METHODS

Patients with pathologically confirmed adenocarcinoma of the pancreas and rectum were eligible. Pretreatment staging included computed tomography, endoscopic ultrasound, and surgical evaluation. Patients received 50.4 Gy of external-beam radiation therapy to the tumor in 28 fractions. Capecitabine and gefitinib were administered throughout the radiation course. Following completion, patients were restaged and considered for resection. Primary end points included determination of dose-limiting toxicity (DLT) and a phase II dose; secondary end points included determination of non-DLTs and preliminary radiographic and pathologic response rates.

RESULTS

Ten patients were entered in the pancreatic study and six in the rectal study. DLT was seen in six of 10 patients in the pancreatic study and two of six patients in the rectal study. The primary DLT in both studies was diarrhea. Two patients developed arterial thrombi.

CONCLUSION

The combination of gefitinib, capecitabine, and radiation in pancreatic and rectal cancer patients resulted in significant toxicity. A recommended phase II dose was not determined in either of our studies. Further investigation with this combination should be approached with caution.

Advances in molecular diagnostics and therapeutics in head and neck cancer

Extensive treatment-related morbidities and stagnant survival rates over the past few decades for patients with squamous cell cancer of the head and neck (SCCHN) emphasize the need for novel diagnostics and therapeutics based on the molecular characteristics of the tumor. The development of an early detection test remains largely preliminary. Much attention has recently been given to saliva-based early detection assays that use accepted tumor markers such as p53 and DNA methylation. Most of these studies have focused on feasibility as opposed to prospective clinical trials. To date, early detection saliva assays have failed to yield a high enough sensitivity and specificity for broad population-based screening. The use of saliva as a noninvasive, inexpensive, and accessible diagnostic substrate remains desirable. Unlike SCCHN diagnostics, molecular-targeted therapies for SCCHN will soon be a reality, with many more compounds in the pipeline. The most promising of these drugs target the epidermal growth factor receptor (EGFR), which is known to be overexpressed in squamous cell carcinomas. Cetuximab, a monoclonal EGFR antibody, has shown efficacy in combination with radiotherapy in advanced SCCHN in a recent phase III trial and is currently being petitioned for US Food and Drug Administration approval. Likewise, erlotinib, an EGFR tyrosine kinase inhibitor, has shown favorable results in phase II trials as monotherapy and in combination with chemotherapy. Gefitinib, another EGFR tyrosine kinase inhibitor, has shown efficacy as monotherapy, in combination with chemotherapy, and with chemoradiotherapy. At least two phase III trials of gefitinib in patients with advanced SCCHN are ongoing. Such low-toxicity, tumor-specific targeting strategies will soon be available for patients with head and neck cancer. The challenge is to establish assays to determine which patients are most likely to benefit from these agents.

Quantitative determination of nuclear and cytoplasmic epidermal growth factor receptor expression in oropharyngeal squamous cell cancer by using automated quantitative analysis

BACKGROUND

Several lines of evidence support the epidermal growth factor receptor (EGFR) as a molecular target for therapy in head and neck squamous cell carcinomas (HNSCC). Determination of tumor EGFR levels by conventional immunohistochemistry has not always predicted antitumor efficacy. Quantitative assays may provide more accurate assessment of the level of EGFR receptor in the tumor, which may thus provide more reliable prognostic and predictive information. We studied the prognostic value of quantitative assessment of EGFR in oropharyngeal squamous cell cancers treated with radiotherapy.

EXPERIMENTAL DESIGN

We studied EGFR protein expression on a tissue microarray composed of 95 oropharyngeal cancer cases using an in situ molecular-based method of quantitative assessment of protein expression (AQUA) and correlated those with clinical and pathologic data. Automated, quantitative analysis uses cytokeratin to define pixels as cancer (tumor mask) within the array spot and measures intensity of EGFR expression using a Cy5-conjugated antibody within the mask. A continuous index score is generated, which is directly proportional to the number of molecules per unit area, and cases were defined as high expressing if they were above the median expression level.

RESULTS

The mean follow-up time for survivors was 44.9 months, and for the entire cohort was 34.8 months. Patients with high tumor EGFR expression levels had a local recurrence rate of 58% compared with 17% for patients with low EGFR tumor expression (P < 0.01). Similarly, patients with high nuclear EGFR expression had a local recurrence rate of 54% compared with 21% for patients with low EGFR nuclear expression (P < 0.05). Additionally, patients with high tumor and nuclear EGFR levels had inferior disease-free survival compared with low expressors (19% versus 43% and 19% versus 45%, respectively. P < 0.05 for each). In multivariate analysis adjusting for well-characterized prognostic variables, high tumor and nuclear EGFR expression levels retained their prognostic significance.

CONCLUSION

The AQUA system provides a continuous measurement of EGFR on paraffin-embedded tissue and was able to reveal the association between EGFR expression and outcome expected from the biological role of EGFR. In the future, EGFR AQUA score may be useful in predicting response to EGFR-targeted therapies.

Randomized trial of radiotherapy versus concurrent chemoradiotherapy followed by adjuvant chemotherapy in patients with American Joint Committee on Cancer/International Union against cancer stage III and IV nasopharyngeal cancer of the endemic variety

PURPOSE

The Intergroup 00-99 Trial for nasopharyngeal cancer (NPC) showed a benefit of adding chemotherapy to radiotherapy. However, there were controversies regarding the applicability of the results to patients in endemic regions. This study aims to confirm the findings of the 00-99 Trial and its applicability to patients with endemic NPC.

PATIENTS AND METHODS

Between September 1997 and May 2003, 221 patients were randomly assigned to receive radiotherapy (RT) alone (n = 110) or chemoradiotherapy (CRT; n = 111). Patients in both arms received 70 Gy in 7 weeks using standard RT portals and techniques. Patients on CRT received concurrent cisplatin (25 mg/m2 on days 1 to 4) on weeks 1, 4, and 7 of RT and adjuvant cisplatin (20 mg/m2 on days 1 to 4) and fluorouracil (1,000 mg/m2 on days 1 to 4) every 4 weeks (weeks 11, 15, and 19) for three cycles after completion of RT. All patients were analyzed by intent-to-treat analysis. The median follow-up time was 3.2 years.

RESULTS

Distant metastasis occurred in 38 patients on RT alone and 18 patients on CRT. The difference in 2-year cumulative incidence was 17% (95% CI, 14% to 20%; P = .0029). The hazard ratio (HR) for disease-free survival was 0.57 (95% CI, 0.38 to 0.87; P = .0093). The 2- and 3-year overall survival (OS) rates were 78% and 85% and 65% and 80% for RT alone and CRT, respectively. The HR for OS was 0.51 (95% CI, 0.31 to 0.81; P = .0061).

CONCLUSION

This report confirms the findings of the Intergroup 00-99 Trial and demonstrates its applicability to endemic NPC. This study also confirms that chemotherapy improves the distant metastasis control rate in NPC.

Multicenter phase I/II study of cetuximab with paclitaxel and carboplatin in untreated patients with stage IV non-small-cell lung cancer

PURPOSE

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors have demonstrated antitumor activity in patients with non-small-cell lung cancer (NSCLC). This study examined the safety profile of the monoclonal antibody EGFR inhibitor, cetuximab, when added to paclitaxel and carboplatin in untreated patients with stage IV NSCLC. Secondary objectives included efficacy and paclitaxel and carboplatin pharmacokinetics during cetuximab treatment.

PATIENTS AND METHODS

Patients with tumor evidence of EGFR by immunohistochemistry, performance status of 0 to 2, and measurable disease received paclitaxel 225 mg/m2 with carboplatin area under the curve = 6 on day 1 every 3 weeks. Cetuximab was administered at 400 mg/m2, 1 week before paclitaxel and carboplatin, then weekly at 250 mg/m2. The regimen continued until disease progression or intolerable toxicity.

RESULTS

Thirty-one of 32 enrolled patients were treated. The most common cetuximab toxicity was rash in 84% of patients (grade 3 in 13%). Pharmacokinetic sampling did not reveal an interaction between carboplatin, paclitaxel, and cetuximab. An objective response was observed in eight patients (26%). With a median follow-up of 19 months, the median time to progression was 5 months, median survival was 11 months, and the 1- and 2-year survival rates were 40% and 16%, respectively.

CONCLUSION

The combination of cetuximab, paclitaxel, and carboplatin was safe and well tolerated in this population of stage IV patients. The response rate, time to progression, and median survival were slightly superior to historical controls treated with paclitaxel and carboplatin alone. A randomized phase II trial has completed accrual.

Enhanced Efficacy of Radioimmunotherapy with 90Y-CHX-A″-DTPA-hu3S193 by Inhibition of Epidermal Growth Factor Receptor (EGFR) Signaling with EGFR Tyrosine Kinase Inhibitor AG1478

PURPOSE

Monoclonal antibodies and tyrosine kinase inhibitors specific for the epidermal growth factor receptor (EGFR) have been shown to enhance the effect of external beam radiation on EGFR-positive tumors. The effect of EGFR signaling abrogation by EGFR tyrosine kinase inhibitor on the efficacy of radioimmunotherapy has not been reported previously. This study investigated the effect of EGFR tyrosine kinase inhibition on the efficacy of radioimmunotherapy in a human cancer xenograft model.

EXPERIMENTAL DESIGN

The humanized anti-Lewis Y antibody hu3S193 and the EGFR tyrosine kinase inhibitor AG1478 were studied. BALB/c nude mice were engrafted with A431 squamous carcinoma cells. Initial biodistribution properties of the 90Y-CHX-A''-DTPA-hu3S193 were evaluated in this model. In therapy experiments, cohorts of four to five xenografted mice were treated with saline as placebo, 0.4 mg AG1478 i.p. (six doses over 2 weeks), single i.v. injections of unlabeled hu3S193, or 90Y-CHX-A''-DTPA-hu3S193 (12.5, 25, 50, or 100 microCi). The combination of 0.4 mg AG1478 i.p. and 25 microCi 90Y-CHX-A''-DTPA-hu3S193 i.v. was subsequently evaluated in the A431 model.

RESULTS

90Y-CHX-A''-DTPA-hu3S193 retained excellent immunoreactivity after radiolabeling. The biodistribution study showed excellent uptake in tumor (90.33 +/- 38.84%ID/g) peaking at 24 to 72 hours after injection and with prolonged retention. 90Y-CHX-A''-DTPA-hu3S193 significantly inhibited A431 xenograft growth at 25, 50, and 100 microCi doses. The combination of 0.4 mg AG1478 with a single dose of 25 microCi 90Y-CHX-A''-DTPA-hu3S193 resulted in a significant enhancement of efficacy compared with either agent alone (P = 0.013).

CONCLUSIONS

The efficacy of radioimmunotherapy with 90Y-CHX-A''-DTPA-hu3S193 is significantly enhanced by EGFR tyrosine kinase inhibitor AG1478. Further investigations of dosing regimens using EGFR tyrosine kinase inhibitors and radioimmunotherapy in the treatment of EGFR expressing tumors are warranted.

Epidermal growth factor receptor directed therapy in head and neck cancer

Squamous cell head and neck cancer (SCCHN) is the seventh most common cause of cancer death worldwide and its incidence is rising rapidly in developing countries. Despite recent advances in managing locally advanced SCCHN, patients with recurrent and metastatic SCCHN have a poor prognosis and little progress has been made its management. Epidermal growth factor receptor (EGFR) has been implicated in the pathogenesis of SCCHN and is a marker of poor prognosis. Recent advances in targeted therapeutics against EGFR are being investigated clinically. In this article, we review the different modalities utilized to inhibit EGFR signaling in SCCHN, including small molecule tyrosine kinase inhibitors, monoclonal antibodies, anti-sense therapy and immunotoxin conjugates. Monotherapy with EGFR inhibitors has demonstrated response rates between 5 and 15% in advanced SCCHN. However, combining EGFR inhibitors with cytotoxic chemotherapy or radiation therapy appears to augment response rates and survival. With the foundation for the use of EGFR inhibitors laid in these studies, future studies will need to optimize the delivery of these agents in combination with conventional therapies.

Integration of novel therapeutics into combined modality therapy of locally advanced non-small cell lung cancer

Novel therapeutic agents (NTA) directed against a wide array of newly described molecular targets are now entering clinical investigation, many in the treatment of non-small cell lung cancer (NSCLC). The great majority of these clinical trials have been directed toward patients with advanced stage (metastatic) disease. More recently, study of NTAs has turned toward earlier-stage disease. Locally advanced, or stage III, NSCLC represents a large and heterogeneous group of patients and several clinically distinct substages. During the last 15 years, randomized clinical trials have shown improved survival with sequential chemoradiation compared with radiation alone and, more recently, the superiority of concurrent versus sequential chemoradiation. As NTAs have increasingly shown clinical activity against NSCLC, questions of how to incorporate them into clinical trials in stage III disease, whether they should be given together with radiotherapy, substituting for chemotherapy, or whether they should be added to current chemoradiation strategies, all remain as issues. Here, we describe conceptual issues, preclinical rationale, and ongoing or planned clinical trials incorporating NTAs into current treatment paradigms for unresectable stage III NSCLC.

Phase II multicenter study of the antiepidermal growth factor receptor monoclonal antibody cetuximab in combination with platinum-based chemotherapy in patients with platinum-refractory metastatic and/or recurrent squamous cell carcinoma of the head and neck

PURPOSE

To evaluate the efficacy and safety of the antiepidermal growth factor receptor monoclonal antibody cetuximab in combination with platinum-based chemotherapy in patients with platinum-refractory recurrent or metastatic squamous cell carcinoma of the head and neck (SCCHN).

PATIENTS AND METHODS

Ninety-six eligible patients received cetuximab (initial dose of 400 mg/m2 followed by subsequent weekly doses of 250 mg/m2) followed by platinum chemotherapy at the same dose and schedule at which progressive disease was documented before entry onto the study.

RESULTS

The response rate, based on an independently read assessment, in the intent-to-treat population was 10%, with a disease control rate (complete response, partial response [PR], and stable disease) of 53%. The median time to progression and overall survival were 85 and 183 days, respectively; both were longest in patients achieving a PR (median, 203.5 and 294 days, respectively). Treatment was well tolerated. The most common cetuximab-related adverse events were skin reactions, particularly an acne-like rash.

CONCLUSION

The combination of cetuximab and platinum chemotherapy is an active and well-tolerated approach to the treatment of this poor-prognosis patient population with platinum-refractory recurrent or metastatic SCCHN for whom there are no recommended standard therapeutic options.

Phase II multicenter study of the epidermal growth factor receptor antibody cetuximab and cisplatin for recurrent and refractory squamous cell carcinoma of the head and neck

PURPOSE

This multicenter phase II study was undertaken to define the efficacy and safety of cetuximab, an antiepidermal growth factor receptor chimeric human and murine monoclonal antibody, administered with cisplatin to patients with refractory metastatic or recurrent squamous cell carcinoma of the head and neck (SCCHN).

PATIENTS AND METHODS

One hundred thirty-two patients were to receive two 3-week cycles with cisplatin/paclitaxel or cisplatin/fluorouracil. Patients (n = 30) with a complete or partial response continued standard therapy. Seventy-six patients with stable disease (SD; n = 51) or progressive disease (PD/1; n = 25) received combination therapy with cetuximab (400 mg/m2 intravenously on day 1, then 250 mg/m2/wk) and cisplatin (75 or 100 mg/m2 intravenously on day 1 every 3 weeks). The protocol was subsequently amended to enroll patients who had developed PD within 90 days after platinum-based therapy (PD/2; n = 54).

RESULTS

Five patients (20%) in PD/1, three patients (6%) in PD/2, and nine patients (18%) with SD achieved an objective response. Median duration of response was 4.2, 4.1, and 7.4 months for the PD/1, PD/2, and SD groups, respectively, with median overall survival times of 6.1, 4.3, and 11.7 months. The most common toxicities were anemia, acne-like skin rash, leukopenia, fatigue and malaise, and nausea and vomiting. Seven patients (5%) developed a grade 3 or 4 hypersensitivity reaction to cetuximab.

CONCLUSION

Cetuximab and cisplatin is an active regimen in refractory SCCHN. The relative contribution of cetuximab is better defined in a single-agent trial. Cetuximab did not exacerbate cisplatin toxicity but was associated with skin rash in a majority of patients and occasional serious allergic reactions. Further study of this compound is warranted.

Concurrent Chemoradiotherapy for Unresectable Stage III Non-Small Cell Lung Cancer

Over the last two decades, several approaches to multimodality therapy have been investigated in patients with advanced unresectable non-small cell lung cancer. These include induction chemotherapy and concurrent chemoradiotherapy. Both approaches have been shown to be superior to radiation therapy alone. However, in several randomized trials, concomitant chemoradiotherapy was shown to be superior to the induction chemotherapy approach. It has been hypothesized that the addition of systemic dose sequential chemotherapy to concurrent chemoradiotherapy, either as induction or as consolidation chemotherapy, might further improve survival rates. Recently, the Cancer and Leukemia Group B reported on a randomized phase III trial directly evaluating the addition of two cycles of carboplatin and paclitaxel to concurrent chemoradiotherapy. In this study, induction chemotherapy failed to further improve survival rates of concurrent chemoradiotherapy. A previously conducted randomized phase II study also suggested no benefit from the addition of induction chemotherapy to concomitant chemoradiotherapy. Favorable phase II data have been published supporting the use of consolidation chemotherapy. However, to date, no large randomized study evaluating a possible benefit from consolidation chemotherapy has been completed. In addition to evaluating optimal sequencing strategies of combined modality therapy, current investigations are also focusing on the integration of novel agents, including chemotherapeutic and targeted therapies. Currently ongoing trials involving novel approaches are reviewed here.

A Fully Human Recombinant IgG-like Bispecific Antibody to Both the Epidermal Growth Factor Receptor and the Insulin-like Growth Factor Receptor for Enhanced Antitumor Activity

Both the epidermal growth factor receptor (EGFR) and the insulin-like growth factor receptor (IGFR) have been implicated in the tumorigenesis of a variety of cancers. Here we propose that simultaneous targeting of both receptors with a bispecific antibody would lead to enhanced antitumor activity. To this end, we produced a recombinant human IgG-like bispecific antibody, a Di-diabody, using the variable regions from two antagonistic antibodies: IMC-11F8 to EGFR and IMC-A12 to IGFR. The Di-diabody binds to both EGFR and IGFR and effectively blocked both EGF- and IGF-stimulated receptor activation and tumor cell proliferation. The Di-diabody also inherited the biological properties from both of its parent antibodies; it triggers rapid and significant IGFR internalization and degradation and mediates effective antibody-dependent cellular cytotoxicity in a variety of tumor cells. Finally, the Di-diabody strongly inhibited the growth of two different human tumor xenografts in vivo. Our results underscore the benefits of simultaneous targeting of two tumor targets with bispecific antibodies.

Mechanisms of enhanced radiation response following epidermal growth factor receptor signaling inhibition by erlotinib (Tarceva)

Erlotinib (Tarceva) is an orally available HER1 (epidermal growth factor receptor, EGFR) tyrosine kinase inhibitor advancing through clinical trials for the treatment of a range of human malignancies. In this study, we examine the capacity of erlotinib to modulate radiation response and investigate specific mechanisms underlying these interactions in human tumor cell lines and xenografts. The impact of erlotinib on cell cycle kinetics was analyzed using flow cytometry, and the impact on apoptosis was evaluated via fluorescein-labeled pan-caspase inhibition and poly(ADP-ribose) polymerase cleavage. Radiation-induced EGFR autophosphorylation and Rad51 expression were examined by Western blot analysis. Radiation survival was analyzed using a clonogenic assay and assessment of in vivo tumor growth was done using a mouse xenograft model system. Microarray studies were carried out using 20 K human cDNA microarray and select genes were validated using quantitative reverse transcription-PCR (RT-PCR). Independently, erlotinib and radiation induce accumulation of tumor cells in G(1) and G(2)-M phase, respectively, with a reduction of cells in S phase. When combined with radiation, erlotinib promotes a further reduction in S-phase fraction. Erlotinib enhances the induction of apoptosis, inhibits EGFR autophosphorylation and Rad51 expression following radiation exposure, and promotes an increase in radiosensitivity. Tumor xenograft studies confirm that systemic administration of erlotinib results in profound tumor growth inhibition when combined with radiation. cDNA microarray analysis assessing genes differentially regulated by erlotinib following radiation exposure identifies a diverse set of genes deriving from several functional classes. Validation is confirmed for several specific genes that may influence radiosensitization by erlotinib including Egr-1, CXCL1, and IL-1beta. These results identify the capacity of erlotinib to enhance radiation response at several levels, including cell cycle arrest, apoptosis induction, accelerated cellular repopulation, and DNA damage repair. Preliminary microarray data suggests additional mechanisms underlying the complex interaction between EGFR signaling and radiation response. These data suggest that the erlotinib/radiation combination represents a strategy worthy of further examination in clinical trials.

Multicenter, phase II study of cetuximab in combination with carboplatin in patients with recurrent or metastatic nasopharyngeal carcinoma

PURPOSE

To evaluate efficacy and toxicity of cetuximab plus carboplatin in recurrent or metastatic nasopharyngeal carcinoma (NPC) resistant to platinum treatment.

PATIENTS AND METHODS

A multicenter, open-label, single-arm, phase II study in patients with epidermal growth factor receptor-expressing NPC who progressed on or within 12 months after termination of platinum-based chemotherapy for recurrent or metastatic disease. Cetuximab was administered at an initial dose of 400 mg/m2 followed by weekly doses of 250 mg/m2. Carboplatin area under the curve 5 was administered every 3 weeks up to a maximum of eight cycles.

RESULTS

Sixty patients were enrolled (46 males, 14 females; median age, 44.5 years; range, 23 to 64 years), and all patients were included in the intent-to-treat and safety analyses. Of the 59 patients assessable for efficacy, there were seven partial responses (11.7%), 29 patients (48.3%) with stable disease, and 23 patients (38.3%) with progressive disease, giving an overall response rate of 11.7% (95% CI, 4.8% to 22.6%). The median time to progression was 81 days in all patients and was longest in the group of patients with a confirmed response (173 days). The median overall survival time was 233 days in all patients. Six patients (10%) experienced serious treatment-related adverse events. Grade 3 or 4 toxicities occurred in 31 patients (51.7%); of these patients, only 19 (31.7%) were considered to have toxicity related to cetuximab.

CONCLUSION

Cetuximab in combination with carboplatin demonstrates clinical activity and an acceptable safety profile in heavily pretreated patients with recurrent or metastatic NPC who had previously experienced treatment failure with platinum-based therapy.

Critical update and emerging trends in epidermal growth factor receptor targeting in cancer

The epidermal growth factor receptor (EGFR) is a receptor tyrosine kinase of the ErbB receptor family that is abnormally activated in many epithelial tumors. The aberrant activation of the EGFR leads to enhanced proliferation and other tumor-promoting activities, which provide a strong rationale to target this receptor family. There are two classes of anti-EGFR agents: monoclonal antibodies (MAbs) directed at the extracellular domain of the receptor and small molecule, adenosine triphosphate-competitive inhibitors of the receptor's tyrosine kinase. Anti-EGFR MAbs have shown antitumor activity in advanced colorectal carcinoma, squamous cell carcinomas of the head and neck, non-small-cell lung cancer (NSCLC) and renal cell carcinomas. The tyrosine kinase inhibitors (TKIs) have a partially different activity profile. They are active against NSCLC, and a specific EGFR inhibitor has shown improvement in survival. Recently, mutations and amplifications of the EGFR gene have been identified in NSCLC and predict for enhanced sensitivity to anti-EGFR TKIs. In addition to specific anti-EGFR TKIs, there are broader acting inhibitors such as dual EGFR HER-2 inhibitors and combined anti-pan-ErbB and antivascular endothelial growth factor receptor inhibitors. Current research efforts are directed at selecting the optimal dose and schedule and identifying predictive factors of response and resistance beyond EGFR gene mutations and/or amplifications. Finally, there is a need for improved strategies to integrate anti-EGFR agents with conventional therapies and to explore combinations with other molecular targeted approaches including other antireceptor therapies, receptor-downstream signaling transduction inhibitors, and targeted approaches interfering with other essential drivers of cancer, such as angiogenesis.

Chemoradiation after Surgery for High‐Risk Head and Neck Cancer Patients: How Strong Is the Evidence?

Patients with locally advanced, operable head and neck squamous cell carcinoma (HNSCC) are known to be at high risk of treatment failure, ranging from local regrowth to lymphatic spread to systemic dissemination. Attacking specifically each of these patterns of failure implies the use of a multimodal approach. Throughout the past two decades the management of stages III/IV HNSCC remained a matter of debate, especially with regards to treatment intensity and sequencing. Surgery and/or radiotherapy were the mainstay of local-regional treatment in patients with locally advanced disease, but treatment outcome often remained disappointing. In the hope of improving the prognosis after radical surgery, cisplatin-based combinations have been administered before surgery, in the interval between surgery and radiotherapy, or after radiotherapy. Until very recently these combinations, at best, decreased systemic failures without having a real impact on local outcome or survival. Indeed, until the mid-1990s, most trials that had tested postoperative combinations of chemotherapy and radiotherapy did not show any significant benefit. In 2004 level I evidence was established with the publication of the results of two large-scale, independent but similar trials conducted in Europe and the U.S. Both studies demonstrated that, compared with postoperative irradiation alone, adjuvant concurrent chemoradiation was more efficacious in terms of local-regional control and disease-free survival. With the publication of these two trials the evidence demonstrating the potential value of concurrent postoperative chemoradiotherapy in high-risk operable head and neck cancer is strong; however, additional studies and comparative analysis of the selection criteria and treatment outcomes across these two trials will be needed to gain a more accurate assessment of benefit and risk levels in specific patients with operable, locally advanced disease.