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1.  Epidermal growth factor receptor targeted therapy in stages III and IV head and neck cancer 
Current Oncology  2010;17(3):37-48.
Question
What are the benefits associated with the use of anti–epidermal growth factor receptor (anti-egfr) therapies in squamous cell carcinoma of the head and neck (hnscc)? Anti-egfr therapies of interest included cetuximab, gefitinib, lapatinib, zalutumumab, erlotinib, and panitumumab.
Perspectives
Head-and-neck cancer includes malignant tumours arising from a variety of sites in the upper aerodigestive tract. The most common histologic type is squamous cell carcinoma, and most common sites are the oral cavity, the oropharynx, the hypopharynx, and the larynx. Worldwide, hnscc is the sixth most common neoplasm, and despite advances in therapy, long-term survival in hnscc patients is poor. Primary surgery followed by chemoradiation, or primary chemoradiation, are the standard treatment options for patients with locally advanced (stages iii–ivb) hnscc; however, meta-analytic data indicate that the benefit of concurrent platinum-based chemotherapy disappears in patients over the age of 70 years.
Cetuximab is a monoclonal antibody approved for use in combination with radiation in the treatment of patients with untreated locally advanced hnscc and as monotherapy for patients with recurrent or metastatic (stage ivc) hnscc who have progressed on platinum-based therapy.
Given the interest in anti-egfr agents in advanced hnscc, the Head and Neck Cancer Disease Site Group (dsg) of Cancer Care Ontario’s Program in Evidence-Based Care (pebc) chose to systematically review the literature pertaining to this topic so as to develop evidence-based recommendations for treatment.
Outcomes
Outcomes of interest included overall and progression-free survival, quality of life, tumour response rate and duration, and the toxicity associated with the use of anti-egfr therapies.
Methodology
The medline, embase, and Cochrane Library databases, the American Society of Clinical Oncology online conference proceedings, the Canadian Medical Association InfoBase, and the National Guidelines Clearinghouse were systematically searched to locate primary articles and practice guidelines. The reference lists from relevant review articles were searched for additional trials. All evidence was reviewed, and that evidence informed the development of the clinical practice guideline. The resulting recommendations were approved by the Report Approval Panel of the pebc, and by the Head and Neck Cancer dsg. An external review by Ontario practitioners completed the final phase of the review process. Feedback from all parties was incorporated to create the final practice guideline.
Results
The electronic search identified seventy-four references that were reviewed for inclusion. Only four phase iii trials met the inclusion criteria for the present guideline. No practice guidelines, systematic reviews, or meta-analyses were found during the course of the literature search.
The randomized controlled trials (rcts) involved three distinct patient populations: those with locally advanced hnscc being treated for cure, those with incurable advanced recurrent or metastatic hnscc being treated with first-line platinum-based chemotherapy, and those with incurable advanced recurrent or metastatic hnscc who had disease progression despite, or who were unsuitable for, first-line platinum-based chemotherapy.
Practice Guideline
These recommendations apply to adult patients with locally advanced (nonmetastatic stages iii–ivb) or recurrent or metastatic (stage ivc) hnscc.
Platinum-based chemoradiation remains the current standard of care for treatment of locally advanced hnscc.
In patients with locally advanced hnscc who are medically unsuitable for concurrent platinumbased chemotherapy or who are over the age of 70 years (because concurrent chemotherapy does not appear to improve overall survival in this patient population), the addition of cetuximab to radical radiotherapy should be considered to improve overall survival, progression-free survival, and time to local recurrence.
Cetuximab in combination with platinum-based combination chemotherapy is superior to chemotherapy alone in patients with recurrent or metastatic hnscc, and is recommended to improve overall survival, progression-free survival, and response rate.
The role of anti-egfr therapies in the treatment of locally advanced hnscc is currently under study in large randomized trials, and patients with hnscc should continue to be offered clinical trials of novel agents aimed at improving outcomes.
Qualifying Statements
Chemoradiation is the current standard of care for patients with locally advanced hnscc, and to date, there is no evidence that compares cetuximab plus radiotherapy with chemoradiation, or that examines whether the addition of cetuximab to chemoradiation is of benefit in these patients. However, five ongoing trials are investigating the effect of the addition of egfr inhibitors concurrently with, before, or after chemoradiotherapy; those trials should provide direction about the best integration of cetuximab into standard treatment.
In patients with recurrent or metastatic hnscc who experience progressive disease despite, or who are unsuitable for, first-line platinum-based chemotherapy, gefitinib at doses of 250 mg or 500 mg daily, compared with weekly methotrexate, did not increase median overall survival [hazard ratio (hr): 1.22; 96% confidence interval (ci): 0.95 to 1.57; p = 0.12 (for 250 mg daily vs. weekly methotrexate); hr: 1.12; 95% ci: 0.87 to 1.43; p = 0.39 (for 500 mg daily vs. weekly methotrexate)] or objective response rate (2.7% for 250 mg and 7.6% for 500 mg daily vs. 3.9% for weekly methotrexate, p > 0.05). As compared with methotrexate, gefitinib was associated with an increased incidence of tumour hemorrhage (8.9% for 250 mg and 11.4% for 500 mg daily vs. 1.9% for weekly methotrexate).
PMCID: PMC2880902  PMID: 20567625
Head-and-neck cancer; epidermal growth factor receptor; egfr inhibitors; overall survival; progression-free survival; tumour response rate
2.  The contribution of cetuximab in the treatment of recurrent and/or metastatic head and neck cancer 
Recurrent and/or metastatic squamous cell carcinoma of the head and neck (HNSCC) continues to be a source of significant morbidity and mortality worldwide. Agents that target the epidermal growth factor receptor (EGFR) have demonstrated beneficial effects in this setting. Cetuximab, a monoclonal antibody against the EGFR, improves locoregional control and overall survival when used as a radiation sensitizer in patients with locoregionally advanced HNSCC undergoing definitive radiation therapy with curative intent. Cetuximab is also active as monotherapy in patients whose cancer has progressed on platinum-containing therapy. In the first-line setting for incurable HNSCC, cetuximab added to platinum-based chemotherapy significantly improves overall survival compared with standard chemotherapy alone. These positive results have had a significant impact on the standard of care for advanced HNSCC. In this review, we will discuss the mechanism of action, clinical data and common toxicities that pertain to the use of cetuximab in the treatment of advanced incurable HNSCC.
PMCID: PMC2921255  PMID: 20714355
cetuximab; squamous cell carcinoma of the head and neck; epidermal growth factor receptor
3.  A randomized, phase II study of afatinib versus cetuximab in metastatic or recurrent squamous cell carcinoma of the head and neck† 
Annals of Oncology  2014;25(9):1813-1820.
Afatinib, an oral irreversible ErbB family blocker, showed comparable activity to cetuximab in patients with recurrent/metastatic head and neck squamous cell carcinoma in this phase II trial. Further, sequential EGFR/ErbB treatment provided sustained clinical benefit in some patients, suggesting a lack of cross-resistance.
Background
Afatinib is an oral, irreversible ErbB family blocker that has shown activity in epidermal growth factor receptor (EGFR)-mutated lung cancer. We hypothesized that the agent would have greater antitumor activity compared with cetuximab in recurrent or metastatic (R/M) head and neck squamous cell carcinoma (HNSCC) patients, whose disease has progressed after platinum-containing therapy.
Patients and methods
An open-label, randomized, phase II trial was conducted in 43 centers; 124 patients were randomized (1 : 1) to either afatinib (50 mg/day) or cetuximab (250 mg/m2/week) until disease progression or intolerable adverse events (AEs) (stage I), with optional crossover (stage II). The primary end point was tumor shrinkage before crossover assessed by investigator (IR) and independent central review (ICR).
Results
A total of 121 patients were treated (61 afatinib, 60 cetuximab) and 68 crossed over to stage II (32 and 36 respectively). In stage I, mean tumor shrinkage by IR/ICR was 10.4%/16.6% with afatinib and 5.4%/10.1% with cetuximab (P = 0.46/0.30). Objective response rate was 16.1%/8.1% with afatinib and 6.5%/9.7% with cetuximab (IR/ICR). Comparable disease control rates were observed with afatinib (50%) and cetuximab (56.5%) by IR; similar results were seen by ICR. Most common grade ≥3 drug-related AEs (DRAEs) were rash/acne (18% versus 8.3%), diarrhea (14.8% versus 0%), and stomatitis/mucositis (11.5% versus 0%) with afatinib and cetuximab, respectively. Patients with DRAEs leading to treatment discontinuation were 23% with afatinib and 5% with cetuximab. In stage II, disease control rate (IR/ICR) was 38.9%/33.3% with afatinib and 18.8%/18.8% with cetuximab.
Conclusion
Afatinib showed antitumor activity comparable to cetuximab in R/M HNSCC in this exploratory phase II trial, although more patients on afatinib discontinued treatment due to AEs. Sequential EGFR/ErbB treatment with afatinib and cetuximab provided sustained clinical benefit in patients after crossover, suggesting a lack of cross-resistance.
doi:10.1093/annonc/mdu216
PMCID: PMC4143093  PMID: 24928832
afatinib; cetuximab; recurrent HNSCC; metastatic HNSCC; EGFR inhibitor therapy
4.  mTOR Co-Targeting in Cetuximab Resistance in Head and Neck Cancers Harboring PIK3CA and RAS Mutations 
Background
Cetuximab, a monoclonal blocking antibody against the epidermal growth factor receptor EGFR, has been approved for the treatment of squamous cell carcinomas of the head and neck (HNSCC). However, only few patients display long-term responses, prompting the search for cetuximab resistance mechanisms and new therapeutic options enhancing cetuximab effectiveness.
Methods
Cetuximab-sensitive HNSCC cells were retro-engineered to express PIK3CA and RAS oncogenes. These cells and HNSCC cells harboring endogenous PIK3CA and RAS oncogenes were xenografted into mice (n = 10 per group) and studied for their biochemical, antitumor, antiangiogenic, and antilymphangiogenic responses to cetuximab and mTOR targeting agents. All P values are two-sided.
Results
Cetuximab treatment of PIK3CA- and RAS-expressing HNSCC xenografts promoted an initial antitumor response, but all tumors relapsed within few weeks. In these tumors, cetuximab did not decrease the activity of mTOR, a downstream signaling target of EGFR, PIK3CA, and RAS. The combined administration of cetuximab and mTOR inhibitors exerted a remarkably increased antitumor activity, particularly in HNSCC cells that are resistant to cetuximab as a single agent. Indeed, cotargeting mTOR together with cetuximab caused a rapid tumor collapse of both PIK3CA- and RAS-expressing HNSCC xenografts (P < .001), concomitant with reduced proliferation (P < .001) and lymphangiogenesis (P < .001).
Conclusion
The presence of PIK3CA and RAS mutations and other alterations affecting the mTOR pathway activity in HNSCC could be exploited to predict the potential resistance to cetuximab, and to select the patients that may benefit the most from the concomitant administration of cetuximab and PI3K and/or mTOR inhibitors as a precision molecular therapeutic option for HNSCC patients.
doi:10.1093/jnci/dju215
PMCID: PMC4133928  PMID: 25099740
5.  Rationale and design of LUX-Head & Neck 1: a randomised, Phase III trial of afatinib versus methotrexate in patients with recurrent and/or metastatic head and neck squamous cell carcinoma who progressed after platinum-based therapy 
BMC Cancer  2014;14:473.
Background
Patients with recurrent and/or metastatic (R/M) head and neck squamous cell carcinoma (HNSCC) receiving platinum-based chemotherapy as their first-line treatment have a dismal prognosis, with a median overall survival (OS) of ~7 months. Methotrexate is sometimes used following platinum failure or in patients not fit enough for platinum therapy, but this agent has not demonstrated any OS improvement. Targeted therapies are a novel approach, with the EGFR-targeting monoclonal antibody cetuximab (plus platinum-based chemotherapy) approved in the US and Europe in the first-line R/M setting, and as monotherapy following platinum failure in the US. However, there is still a high unmet medical need for new treatments that improve outcomes in the second-line R/M setting following failure on first-line platinum-containing regimens. Afatinib, an irreversible ErbB family blocker, was recently approved for the first-line treatment of EGFR mutation-positive metastatic non-small cell lung cancer. Afatinib has also shown clinical activity similar to cetuximab in a Phase II proof-of-concept HNSCC trial. Based on these observations, the Phase III, LUX-Head & Neck 1 study is evaluating afatinib versus methotrexate in R/M HNSCC patients following progression on platinum-based chemotherapy in the R/M setting.
Methods/Design
Patients with progressive disease after one first-line platinum-based chemotherapy are randomised 2:1 to oral afatinib (starting dose 40 mg once daily) or IV methotrexate (starting dose 40 mg/m2 once weekly) administered as monotherapy with best supportive care until progression or intolerable adverse events. Efficacy of afatinib versus methotrexate will be assessed in terms of progression-free survival (primary endpoint). Disease progression will be evaluated according to RECIST v1.1 by investigator and independent central review. Secondary endpoints include OS, tumour response and safety. Health-related quality of life and biomarker assessments will also be performed.
Discussion
If the LUX-Head & Neck 1 trial meets its primary endpoint, it will demonstrate the ability of afatinib to elicit an improved treatment benefit versus a commonly used chemotherapy agent in the second-line treatment of R/M HNSCC patients who have failed on first-line platinum-based therapy, confirm the clinical efficacy of afatinib observed in the Phase II proof-of-concept study, and establish a new standard of care for this patient population.
doi:10.1186/1471-2407-14-473
PMCID: PMC4079914  PMID: 24973959
Afatinib; Methotrexate; Head and neck; Phase III; Recurrent; Metastatic
6.  Impact of human papilloma virus infection on the response of head and neck cancers to anti-epidermal growth factor receptor antibody therapy 
Cell Death & Disease  2014;5(2):e1091-.
Infection with human papillomaviruses (HPVs) characterizes a distinct subset of head and neck squamous cell cancers (HNSCCs). HPV-positive HNSCC preferentially affect the oropharynx and tonsils. Localized HPV-positive HNSCCs have a favorable prognosis and treatment outcome. However, the impact of HPV in advanced or metastatic HNSCC remains to be defined. In particular, it is unclear whether HPV modulates the response to cetuximab, an antibody targeting the epidermal growth factor receptor (EGFR), which is a mainstay of treatment of advanced HNSCC. To this end, we have examined the sensitivity of HPV-positive and -negative HNSCC models to cetuximab and cytotoxic drugs in vitro and in vivo. In addition, we have stably expressed the HPV oncogenes E6 and E7 in cetuximab-sensitive cancer cell lines to specifically investigate their role in the antibody response. The endogenous HPV status or the expression of HPV oncogenes had no significant impact on cetuximab-mediated suppression of EGFR signaling and proliferation in vitro. Cetuximab effectively inhibited the growth of E6- and E7-expressing tumors grafted in NOD/SCID mice. In support, formalin-fixed, paraffin-embedded tumor samples from cetuximab-treated patients with recurrent or metastatic HNSCC were probed for p16INK4a expression, an established biomarker of HPV infection. Response rates (45.5% versus 45.5%) and median progression-free survival (97 versus 92 days) following cetuximab-based therapy were similar in patients with p16INK4A-positive and p16INK4A-negative tumors. In conclusion, HPV oncogenes do not modulate the anti-EGFR antibody response in HSNCC. Cetuximab treatment should be administered independently of HPV status.
doi:10.1038/cddis.2014.62
PMCID: PMC3944273  PMID: 24577089
HNSCC; cetuximab; HPV; resistance; EGFR; ADCC
7.  Epidermal growth factor receptor variant III mediates head and neck cancer cell invasion via STAT3 activation 
Oncogene  2010;29(37):5135-5145.
Epidermal Growth Factor Receptor (EGFR) is frequently over-expressed in head and neck squamous cell carcinoma (HNSCC) where aberrant signaling downstream of this receptor contributes to tumor growth. EGFR variant III (EGFRvIII) is the most commonly altered form of EGFR and contains a truncated ligand-binding domain. We previously reported that EGFRvIII is expressed in up to 40% of HNSCC tumors where it is associated with increased proliferation, tumor growth and chemoresistance to anti-tumor drugs including the EGFR targeting monoclonal antibody cetuximab. Cetuximab was FDA-approved in 2006 for HNSCC but has not been shown to prevent invasion or metastasis. The present study was undertaken to evaluate the mechanisms of EGFRvIII-mediated cell motility and invasion in HNSCC. We found that EGFRvIII induced HNSCC cell migration and invasion in conjunction with increased STAT3 activation, which was not abrogated by cetuximab treatment. Further investigation demonstrated that EGF-induced expression of the STAT3 target gene HIF1-α, was abolished by cetuximab in HNSCC cells expressing wild-type EGFR under hypoxic conditions, but not in EGFRvIII-expressing HNSCC cells. These results suggest that EGFRvIII mediates HNSCC cell migration and invasion via increased STAT3 activation and induction of HIF1-α, which contribute to cetuximab resistance in EGFRvIII-expressing HNSCC tumors.
doi:10.1038/onc.2009.279
PMCID: PMC2940981  PMID: 20622897
head and neck cancer; epidermal growth factor receptor; EGFRvIII; STAT3 and cancer cell invasion
8.  Treatment of Recurrent Metastatic Head and Neck Cancer: Focus on Cetuximab 
EGFR belongs to the ErbB family of receptor tyrosine kinases and is associated with worse prognosis in head and neck squamous cell carcinoma (HNSCC). Cetuximab is a monoclonal antibody to the extracellular domain of EGFR and inhibits its downstream actions via multiple mechanisms. Besides its proven efficacy in locally advanced and incurable HNSCC, cetuximab has the distinct advantage of having a relatively tolerable side effect profile and not potentiating radiation toxicity. Though therapies for advanced HNSCC are evolving, locoregional recurrence and/or distant metastases occur in a large percentage of patients. Though some patients can be salvaged with surgery or radiation therapy, the majority are incurable, and are treated palliatively with systemic therapy. In the setting of first line therapy for recurrent/metastatic HNSCC, the EXTREME trial provided level 1 evidence that cetuximab improves overall survival when combined with cisplatinum and 5 FU. Following progression on first line chemotherapy, several phase II trials suggest that cetuximab monotherapy is a reasonable choice in this setting. Future studies should concentrate on clinical and molecular markers that may allow more personalized approaches to treating HNSCC, and combining EGFR inhibitors with other agents in a synergistic approach.
doi:10.4137/CMENT.S5129
PMCID: PMC3791949  PMID: 24179404
recurrent; metastatic; SCC; squamous cell carcinoma; EGFR; epidermal growth factor receptor; cetuximab
9.  Approval Summary: Cetuximab in Combination With Cisplatin or Carboplatin and 5-Fluorouracil for the First-Line Treatment of Patients With Recurrent Locoregional or Metastatic Squamous Cell Head and Neck Cancer 
The Oncologist  2013;18(4):460-466.
The present cetuximab U.S. Food and Drug Administration submission seeks to expand the squamous cell head and neck cancer indication to include recurrent locoregional or metastatic disease. Cetuximab, in combination with platinum-based therapy and 5-fluorouracil (FU), is compared to platinum-based therapy and 5-FU alone.
Learning Objectives
Compare survival outcomes among patients with SCCHN treated with a platinum/5 -FU regimen with and without cetuximab.Compare adverse event profiles among patients with SCCHN treated with a platinum/5 -FU regimen with and without cetuximab.Describe potential risk-benefit issues identified in the EU and US studies.
On November 7, 2011, the U.S. Food and Drug Administration approved cetuximab in combination with cisplatin or carboplatin and 5-fluorouracil for the first-line treatment of patients with recurrent locoregional or metastatic squamous cell head and neck cancer. Approval was based on a randomized study of 442 patients conducted outside the U.S. Cisplatin (100 mg/m2 intravenously) or carboplatin (area under the curve 5 intravenously) on day 1 with 5-fluorouracil (1,000 mg/m2/day continuous intravenous infusion days 1–4) were administered every 3 weeks. Cetuximab, 400 mg/m2 intravenously, was administered initially followed by cetuximab, 250 mg/m2 intravenously weekly. After completion of six planned treatment courses, cetuximab patients without progression continued cetuximab 250 mg/m2 weekly. The study used European Union (EU)-approved cetuximab rather than U.S.-approved cetuximab. U.S.-approved cetuximab provides approximately 28% higher exposure relative to EU-approved cetuximab in a pharmacokinetic comparability study in monkeys. Overall survival, the primary efficacy endpoint, was significantly improved in cetuximab-treated patients (hazard ratio [HR]: 0.80; 95% confidence interval [CI]: 0.64–0.98; p = .034, stratified log-rank test). Median survival times were 10.1 and 7.4 months, respectively. Progression-free survival (PFS) was also significantly improved in patients receiving cetuximab (HR: 0.57; 95% CI: 0.46–0.72; p < .0001). Median PFS times were 5.5 and 3.3 months, respectively. Response rates were 35.6% and 19.5% (odds ratio: 2.33; 95% CI: 1.50–3.60; p = .0001). Adverse reactions (≥25%) from cetuximab plus chemotherapy treatment included nausea, anemia, vomiting, neutropenia, rash, asthenia, diarrhea, and anorexia. Conjunctivitis occurred in 10% of cetuximab patients. Other adverse reactions, sometimes severe, included infusion reactions, hypomagnesemia, hypocalcemia, and hypokalemia.
doi:10.1634/theoncologist.2012-0458
PMCID: PMC3639534  PMID: 23576486
Cetuximab; Erbitux; Head and neck cancer; Advanced disease
10.  Epidermal growth factor receptor cooperates with Src family kinases in acquired resistance to cetuximab 
Cancer biology & therapy  2009;8(8):696-703.
The epidermal growth factor receptor (EGFR) is a receptor tyrosine kinase that plays a major role in oncogenesis. Cetuximab is an EGFR-blocking antibody that is FDA approved for use in patients with metastatic colorectal cancer (mCRC) and head and neck squamous cell carcinoma (HNSCC). Although cetuximab has shown strong clinical benefit for a subset of cancer patients, most become refractory to cetuximab therapy. We reported that cetuximab-resistant NSCLC line NCI-H226 cells have increased steady-state expression and activity of EGFR secondary to altered trafficking/degradation and this increase in EGFR expression and activity lead to hyper-activation of HER3 and down stream signals to survival. We now present data that Src family kinases (SFKs) are highly activated in cetuximab-resistant cells and enhance EGFR activation of HER3 and PI(3)K/Akt. Studies using the Src kinase inhibitor dasatinib decreased HER3 and PI(3)K/Akt activity. In addition, cetuximab-resistant cells were resensitized to cetuximab when treated with dasatinib. These results indicate that SFKs and EGFR cooperate in acquired resistance to cetuximab and suggest a rationale for clinical strategies that investigate combinatorial therapy directed at both the EGFR and SFKs in patients with acquired resistance to cetuximab.
PMCID: PMC2895567  PMID: 19276677
EGFR; cetuximab; resistance; Src-family kinases; dasatinib
11.  Dasatinib blocks cetuximab- and radiation-induced nuclear translocation of the epidermal growth factor receptor in head and neck squamous cell carcinoma 
Background and Purpose
The aberrant expression of epidermal growth factor receptor (EGFR) has been linked to the etiology of head and neck squamous cell carcinoma (HNSCC). The first major phase III trial combining cetuximab with radiation confirmed a strong survival advantage. However, both cetuximab and radiation can promote EGFR translocation to the nucleus where it enhances resistance to both of these modalities. In this report we sought to determine how to block cetuximab and radiation–induced translocation of EGFR to the nucleus in HNSCC cell lines.
Material and Methods
We utilized three established HNSCC cell lines, SCC1, SCC6 and SCC1483 and measured nuclear translocation of EGFR after treatment with cetuximab or radiation. We then utilized dasatinib (BMS-354825), a potent, orally bioavailable inhibitor of several tyrosine kinases, including the Src Family Kinases, to determine if SFKs blockade could abrogate cetuximab and radiation-induced nuclear EGFR translocation.
Results
Cetuximab and radiation treatment of all three HNSCC lines lead to translocation of the EGFR to the nucleus. Blockade of SFKs abrogated cetuximab and radiation-induced EGFR translocation to the nucleus.
Conclusions
The data presented in this report suggests that both cetuximab and radiation can promote EGFR translocation to the nucleus and dasatinib can inhibit this process. Collectively these findings may suggest that dasatinib can limit EGFR translocation to the nucleus and may enhance radiotherapy plus cetuximab in HNSCC.
doi:10.1016/j.radonc.2010.06.010
PMCID: PMC2974772  PMID: 20667610
EGFR; cetuximab; radiation; Src family kinases; dasatinib; head and neck cancer
12.  Preclinical modeling of EGFR inhibitor resistance in head and neck cancer 
Cancer Biology & Therapy  2012;13(10):935-945.
The epidermal growth factor receptor (EGFR) is widely expressed in head and neck squamous cell carcinomas (HNSCC) and can activate many growth and survival pathways within tumor cells. Despite ubiquitous EGFR expression, therapies targeting the receptor are only modestly effective in the treatment of HNSCC. A consistent mechanism of resistance to EGFR targeting agents has not yet been identified in HNSCC likely due, in part, to the paucity of preclinical models. We assessed the in vitro and in vivo responses of a panel of 10 genotypically validated HNSCC cell lines to the EGFR inhibitors erlotinib and cetuximab to determine their validity as models of resistance to these agents. We defined a narrow range of response to erlotinib in HNSCC cells in vitro and found a positive correlation between EGFR protein expression and erlotinib response. We observed cross-sensitivity in one HNSCC cell line, 686LN, between erlotinib and cetuximab in vivo. We attempted to generate models of cetuximab resistance in HNSCC cell line-derived xenografts and heterotopic tumorgrafts generated directly from primary patient tumors. While all 10 HNSCC cell line xenografts tested were sensitive to cetuximab in vivo, heterotopic patient tumorgrafts varied in response to cetuximab indicating that these models may be more representative of clinical responses. These studies demonstrate the limitations of using HNSCC cell lines to reflect the heterogeneous clinical responses to erlotinib and cetuximab, and suggest that different approaches including heterotopic tumorgrafts may prove more valuable to elucidate mechanisms of clinical resistance to EGFR inhibitors in HNSCC.
doi:10.4161/cbt.20846
PMCID: PMC3414414  PMID: 22785204
HNSCC; cetuximab; cetuximab resistance; epidermal growth factor receptor (EGFR); erlotinib; erlotinib resistance; heterotopic tumorgraft; xenograft
13.  Regulation of Heparin-Binding EGF-Like Growth Factor by miR-212 and Acquired Cetuximab-Resistance in Head and Neck Squamous Cell Carcinoma 
PLoS ONE  2010;5(9):e12702.
Background
We hypothesized that chronic inhibition of epidermal growth factor receptor (EGFR) by cetuximab, a monoclonal anti-EGFR antibody, induces up-regulation of its ligands resulting in resistance and that microRNAs (miRs) play an important role in the ligand regulation in head and neck squamous cell carcinoma (HNSCC).
Methodology/Principal Findings
Genome-wide changes in gene and miR expression were determined in cetuximab-sensitive cell line, SCC1, and its resistant derivative 1Cc8 using DNA microarrays and RT-PCR. The effects of differentially expressed EGFR ligands and miRs were examined by MTS, colony formation, ELISA, and western blot assays. Heparin-binding EGF-like growth factor (HB-EGF) and its regulator, miR-212, were differentially expressed with statistical significance when SCC1 and 1Cc8 were compared for gene and miR expression. Stimulation with HB-EGF induced cetuximab resistance in sensitive cell lines. Inhibition of HB-EGF and the addition of miR-212 mimic induced cetuximab sensitivity in resistant cell lines. MicroRNA-212 and HB-EGF expression were inversely correlated in an additional 33 HNSCC and keratinocyte cell lines. Six tumors and 46 plasma samples from HNSCC patients were examined for HB-EGF levels. HB-EGF plasma levels were lower in newly diagnosed HNSCC patients when compared to patients with recurrent disease.
Conclusions/Significance
Increased expression of HB-EGF due to down-regulation of miR-212 is a possible mechanism of cetuximab resistance. The combination of EGFR ligand inhibitors or miR modulators with cetuximab may improve the clinical outcome of cetuximab therapy in HNSCC.
doi:10.1371/journal.pone.0012702
PMCID: PMC2938338  PMID: 20856931
14.  Efficacy of gemcitabine and cetuximab combination treatment in head and neck squamous cell carcinoma 
Molecular and Clinical Oncology  2013;1(5):918-924.
Head and neck squamous cell carcinoma (HNSCC) may be curable with surgery, radiation and chemotherapy in its early stages. However, recurrence and metastasis often prevail following primary treatment in advanced stage cases and are associated with significant morbidity and mortality. In this study we investigated the combination therapy of gemcitabine and cetuximab for HNSCC. The UM-SCC-6 and UM-SCC-23 HNSCC cell lines were analyzed following treatment with gemcitabine and cetuximab. To determine the mechanism of action of this combination treatment, the cell cycle distributions following gemcitabine and/or cetuximab treatment were analyzed by flow cytometry and apoptosis assay. Gemcitabine and cetuximab combination treatment exerted an enhanced cytotoxic effect. The cell cycle analysis demonstrated that cells accumulated in the S phase following gemcitabine treatment and G1 arrest occurred following cetuximab treatment. An increase in sub-G1 phase cells was also observed following treatment with the two drugs. In an apoptosis assay, caspase 3/7 activity was found to be higher when administering a combination of gemcitabine and cetuximab compared to each agent administered alone. Gemcitabine and cetuximab are individually effective against HNSCC and an enhanced growth inhibitory effect may be expected when these agents are used in combination.
doi:10.3892/mco.2013.159
PMCID: PMC3916031  PMID: 24649271
head and neck squamous cell carcinoma; chemotherapy; cetuximab; gemcitabine; cell cycle
15.  Hedgehog signaling alters reliance on EGF receptor signaling and mediates anti-EGFR therapeutic resistance in head and neck cancer 
Cancer research  2013;73(11):3381-3392.
The epidermal growth factor receptor (EGFR)-directed monoclonal antibody cetuximab is the only targeted therapy approved for the treatment of head and neck squamous cell carcinoma (HNSCC), but is only effective in a minority of patients. Epithelial-to-mesenchymal transition (EMT) has been implicated as a drug resistance mechanism in multiple cancers, and the EGFR and Hedgehog pathways (HhP) are relevant to this process, but the interplay between the two pathways has not been defined in HNSCC. Here we show that HNSCC cells that were naturally sensitive to EGFR inhibition over time developed increased expression of the HhP transcription factor GLI1 as they became resistant after long-term EGFR inhibitor exposure. This robustly correlated with an increase in Vimentin expression. Conversely, the HhP negatively regulated an EGFR-dependent, EMT-like state in HNSCC cells, and pharmacological or genetic inhibition of HhP signaling pushed cells further into an EGFR-dependent phenotype, increasing expression of ZEB1 and VIM. In vivo treatment with cetuximab resulted in tumor shrinkage in four out of six HNSCC patient-derived xenografts; however they eventually re-grew. Cetuximab in combination with the HhP inhibitor IPI-926 eliminated tumors in two cases and significantly delayed re-growth in the other two cases. Expression of EMT genes TWIST and ZEB2 was increased in sensitive xenografts suggesting a possible resistant mesenchymal population. In summary, we report that EGFR-dependent HNSCC cells can undergo both EGFR-dependent and -independent EMT and HhP signaling is a regulator in both processes. Cetuximab plus IPI-926 forces tumor cells into an EGFR-dependent state delaying or completely blocking tumor recurrence.
doi:10.1158/0008-5472.CAN-12-4047
PMCID: PMC3674118  PMID: 23576557
Head and neck squamous cell cancer; hedgehog pathway; epidermal growth factor receptor pathway; epithelial to mesenchymal transition
16.  Rapid palliation of symptoms with platinum-based chemotherapy plus cetuximab in recurrent oral cancer: a case report 
Background
Symptom control is an important consideration in the choice of treatment for patients with recurrent and/or metastatic squamous cell carcinoma of the head and neck (SCCHN). Patients who demonstrate objective tumour responses to platinum-based chemotherapy are more likely to have symptom relief than those who do not have such responses. A phase III trial (EXTREME) showed that adding the epidermal growth factor receptor (EGFR)-targeting IgG1 monoclonal antibody cetuximab to first-line platinum-based chemotherapy significantly prolongs progression-free and overall survival and increases response rate compared with platinum-based chemotherapy alone. We report here the case of a 60-year old female with recurrent squamous cell carcinoma of the gum who had rapid palliation of symptoms and reduction of facial disease mass following treatment with a combination of carboplatin/5-fluorouracil (5-FU) and cetuximab.
Case presentation
The patient was diagnosed with T4N0 M0 disease of the oral cavity in November 2006 and underwent surgery, with R0 resection, followed by adjuvant radiotherapy and concomitant cisplatin chemotherapy. Around 3 months later, the disease recurred and the patient had severe pain (9/10 on a visual pain scale), marked facial oedema and a palpable facial mass of 89 mm. The patient received 4 21-day cycles of carboplatin (AUC 5), 5-FU (1,000 mg/m2/day for 4 days) and cetuximab (400 mg/m2 initial dose followed by subsequently weekly doses of 250 mg/m2), with continuation of cetuximab monotherapy at the end of this time, and pain relief with topical fentanyl and oral morphine. After 7 days of treatment, pain had reduced to 2/10, with discontinuation of morphine after 4 days, and the facial mass had reduced to 70 mm. After 2 cycles of treatment, the facial mass had decreased to 40 mm. After 3 cycles of treatment, pain and facial oedema had resolved completely and a cervical computed tomography scan showed a marked reduction in tumour mass. Cetuximab monotherapy was continued uninterrupted for 7 months.
Conclusion
This case illustrates the rapid reduction of tumour mass and disease-associated pain and oedema that can be achieved with a combination of platinum-based chemotherapy and cetuximab in recurrent and/or metastatic SCCHN.
doi:10.1186/1758-3284-2-3
PMCID: PMC2832769  PMID: 20181021
17.  Cost-Effectiveness of Adding Cetuximab to Platinum-Based Chemotherapy for First-Line Treatment of Recurrent or Metastatic Head and Neck Cancer 
PLoS ONE  2012;7(6):e38557.
Purpose
To assess the cost effectiveness of adding cetuximab to platinum-based chemotherapy in first-line treatment of patients with recurrent or metastatic head and neck squamous cell carcinoma (HNSCC) from the perspective of the Canadian public healthcare system.
Methods
We developed a Markov state transition model to project the lifetime clinical and economic consequences of recurrent or metastatic HNSCC. Transition probabilities were derived from a phase III trial of cetuximab in patients with recurrent or metastatic HNSCC. Cost estimates were obtained from London Health Sciences Centre and the Ontario Case Costing Initiative, and expressed in 2011 CAD. A three year time horizon was used. Future costs and health benefits were discounted at 5%.
Results
In the base case, cetuximab plus platinum-based chemotherapy compared to platinum-based chemotherapy alone led to an increase of 0.093 QALY and an increase in cost of $36,000 per person, resulting in an incremental cost effectiveness ratio (ICER) of $386,000 per QALY gained. The cost effectiveness ratio was most sensitive to the cost per mg of cetuximab and the absolute risk of progression among patients receiving cetuximab.
Conclusion
The addition of cetuximab to standard platinum-based chemotherapy in first-line treatment of patients with recurrent or metastatic HNSCC has an ICER that exceeds $100,000 per QALY gained. Cetuximab can only be economically attractive in this patient population if the cost of cetuximab is substantially reduced or if future research can identify predictive markers to select patients most likely to benefit from the addition of cetuximab to chemotherapy.
doi:10.1371/journal.pone.0038557
PMCID: PMC3379991  PMID: 22745668
18.  Dacomitinib, an Irreversible Pan-ErbB Inhibitor Significantly Abrogates Growth in Head and Neck Cancer Models That Exhibit Low Response to Cetuximab 
PLoS ONE  2013;8(2):e56112.
Aberrant epidermal growth factor (EGF) signaling is associated with tumor growth in squamous cell carcinoma of the head and neck in humans (HNSCC), and is a major focus of targeted therapy. Cetuximab, a monoclonal antibody against EGFR, has been successful at prolonging survival but has only a 10% tumor shrinkage response rate in a clinical setting. The goal of this study was to compare dacomitinib (PF-00299804), a next generation small molecule tyrosine kinase inhibitor that irreversibly blocks multiple HER family receptors (HER-1 (EGFR), HER-2 and HER-4 tyrosine kinases), to cetuximab, the current FDA approved anti-EGFR medication for HNSCC and erlotinib, an EGFR specific small molecule tyrosine kinase inhibitor. Dacomitinib, erlotinib and cetuximab were tested in a panel of 27 HNSCC cell lines. Treatment with 100 ug/ml of cetuximab or 1 uM of erlotinib inhibited growth by at least 50% in 7/27 cell lines, while treatment with 1 uM of dacomitinib had similar growth inhibition in 17/27 lines. Cell lines representing three levels of sensitivity to dacomitinib were further examined using Western blots, cell cycle and apoptosis analysis. Treatment with 100 nM of dacomitinib reduced EGFR activity and downstream AKT and ERK pathways more effectively than treatment with 100 ug/ml of cetuximab in all ten tested lines. Although both compounds induced apoptosis at similar levels, dacomitinib caused greater G0/G1 arrest. Sensitivity to EGFR blockade was associated with levels of EGFR and ERK and was not associated with common oncogenic mutations and copy number variations. Phosphorylated and total EGFR and ERK levels correlate with sensitivity to both cetuximab and dacomitinib. Three of the four lines in the exquisitely sensitive group had the highest levels of phosphorylated and total EGFR and ERK among the ten lines selected, while the three resistant lines collectively had the lowest levels. Neither pAKT nor tAKT was associated with sensitivity.
doi:10.1371/journal.pone.0056112
PMCID: PMC3566064  PMID: 23405260
19.  Honokiol inhibits EGFR signaling and enhances the antitumor effects of EGFR inhibitors 
Purpose
To investigate the utility of honokiol, a naturally-occurring compound, in the treatment of head and neck squamous cell carcinoma (HNSCC) as well as its ability to target the epidermal growth factor receptor (EGFR), a critical therapeutic target in HNSCC, and to enhance the effects of other EGFR-targeting therapies.
Experimental Design
Human HNSCC cell lines and the xenograft animal model of HNSCC were employed to test the effects of honokiol treatment.
Results
Honokiol was found to inhibit growth in human HNSCC cell lines, with EC50s ranging from 3.3-7.4 μM, and to induce apoptosis, as shown through annexin V staining. These effects were associated with inhibition of EGFR signaling, including downstream inhibition of MAPK, Akt and STAT3 and expression of STAT3 target genes, Bcl-XL and cyclin D1. Furthermore, honokiol enhanced the growth inhibitory and anti-invasion activity of the EGFR-targeting agent, erlotinib. While HNSCC xenograft models did not demonstrate significant inhibition of in vivo tumor growth with honokiol treatment alone, the combination of honokiol plus cetuximab, an FDA-approved EGFR inhibitor for this malignancy, significantly enhanced growth inhibition. Finally, HNSCC cells rendered resistant to erlotinib retained sensitivity to the growth inhibitory effects of honokiol.
Conclusions
These results suggest that honokiol may be an effective therapeutic agent in HNSCC where it can augment the effects of EGFR inhibitors and overcome drug resistance.
doi:10.1158/1078-0432.CCR-10-0333
PMCID: PMC2871379  PMID: 20388852
20.  Anti-tumor mechanisms of targeting the PDK1 pathway in head and neck cancer 
Molecular cancer therapeutics  2012;11(6):1236-1246.
G-protein-coupled receptors (GPCRs) activate the epidermal growth factor receptor (EGFR) and mediate EGFR-independent signaling pathways to promote the growth of a variety of cancers including head and neck squamous cell carcinoma (HNSCC). Identification of the common signaling mechanisms involved in GPCR-induced EGFR-dependent and independent processes will facilitate the development of more therapeutic strategies. In this study, we hypothesized that phosphoinositide-dependent kinase 1 (PDK1) contributes to GPCR-EGFR crosstalk and signaling in the absence of EGFR and suggests that inhibition of the PDK1 pathway may be effective in the treatment of HNSCC. The contribution of PDK1 to the EGFR-dependent and independent signaling in HNSCC was determined using RNAi, a kinase-dead mutant and pharmacological inhibition. In vivo xenografts studies were also performed to determine the efficacy of targeting PDK1 alone or in combination with the FDA-approved EGFR inhibitor cetuximab. PDK1 contributed to both GPCR-induced EGFR activation and cell growth. PDK1 also mediated activation of p70S6K in the absence of EGFR. Blockade of PDK1 with a small molecule inhibitor (AR-12) abrogated HNSCC growth, induced apoptosis and enhanced the anti-proliferative effects of EGFR tyrosine kinase inhibitors in vitro. HNSCC xenografts expressing kinase-dead PDK1 demonstrated increased sensitivity to cetuximab compared to vector-transfected controls. Administration of AR-12 substantially decreased HNSCC tumor growth in vivo. These cumulative results demonstrate that PDK1 is a common signaling intermediate in GPCR-EGFR crosstalk and EGFR-independent signaling, and where targeting the PDK1 pathway may represent a rational therapeutic strategy to enhance clinical responses to EGFR inhibitors in HNSCC.
doi:10.1158/1535-7163.MCT-11-0936
PMCID: PMC3413198  PMID: 22491800
PDK1; Head and neck cancer; GPCR-EGFR crosstalk; AR-12
21.  Targeting TORC1/2 Enhances Sensitivity to EGFR Inhibitors in Head and Neck Cancer Preclinical Models1 
Neoplasia (New York, N.Y.)  2012;14(11):1005-1014.
Head and neck squamous cell carcinoma (HNSCC) is characterized by overexpression of the epidermal growth factor receptor (EGFR) where treatments targeting EGFR have met with limited clinical success. Elucidation of the key downstream-pathways that remain activated in the setting of EGFR blockade may reveal new therapeutic targets. The present study was undertaken to test the hypothesis that inhibition of the mammalian target of rapamycin (mTOR) complex would enhance the effects of EGFR blockade in HNSCC preclinical models. Treatment of HNSCC cell lines with the newly developed TORC1/TORC2 inhibitor OSI-027/ASP4876 resulted in dose-dependent inhibition of proliferation with abrogation of phosphorylation of known downstream targets including phospho-AKT (Ser473), phospho-4E-BP1, phospho-p70s6K, and phospho-PRAS40. Furthermore, combined treatment with OSI-027 and erlotinib resulted in enhanced biochemical effects and synergistic growth inhibition in vitro. Treatment of mice bearing HNSCC xenografts with a combination of the Food and Drug Administration (FDA)-approved EGFR inhibitor cetuximab and OSI-027 demonstrated a significant reduction of tumor volumes compared with either treatment alone. These findings suggest that TORC1/TORC2 inhibition in conjunction with EGFR blockade represents a plausible therapeutic strategy for HNSCC.
PMCID: PMC3514742  PMID: 23226094
22.  Inhibition of EGFR or IGF-1R signaling enhances radiation response in head and neck cancer models but concurrent inhibition has no added benefit 
Cancer Medicine  2014;4(1):65-74.
Interaction between the epidermal growth factor receptor (EGFR) and the insulin-like growth factor receptor (IGF-1R) has been well established in many cancer types. We investigated the effects of cetuximab (EGFR antibody) and IMC-A12 (IGF-1R antibody) on the response of head and neck squamous cell carcinoma (HNSCC) to radiation therapy (RT). The effects of cetuximab and IMC-A12 on cell viability and radiosensitivity were determined by clonogenic cell survival assay. Formation of nuclear γ-H2AX and 53BP1 foci was monitored by immunofluorescence. Alterations in target signaling were analyzed by Western blots. In vivo tumor growth delay assay was performed to determine the efficacy of triple therapy with IMC-A12, cetuximab, and RT. In vitro data showed that cetuximab differentially affected the survival and the radiosensitivity of HNSCC cells. Cetuximab suppressed DNA repair that was evident by the prolonged presence of nuclear γ-H2AX and 53BP1 foci. IMC-A12 did not have any effect on the cell survival. However, it increased the radiosensitivity of one of the cell lines. EGFR inhibition increased IGF-1R expression levels and also the association between EGFR and IGF-1R. Addition of IMC-A12 to cetuximab did not increase the radiosensitivity of these cells. Tumor xenografts exhibited enhanced response to RT in the presence of either cetuximab or IMC-A12. Concurrent treatment regimen failed to further enhance the tumor response to cetuximab and/or RT. Taken together our data suggest that concomitant inhibition of both EGFR and IGF-1R pathways did not yield additional therapeutic benefit in overcoming resistance to RT.
doi:10.1002/cam4.345
PMCID: PMC4312119  PMID: 25355701
Head and neck squamous cell carcinoma; IGF-1R and EGFR signaling; radiosensitivity; tumor response to radiation
23.  KRAS Testing for Anti-EGFR Therapy in Advanced Colorectal Cancer 
Executive Summary
In February 2010, the Medical Advisory Secretariat (MAS) began work on evidence-based reviews of the literature surrounding three pharmacogenomic tests. This project came about when Cancer Care Ontario (CCO) asked MAS to provide evidence-based analyses on the effectiveness and cost-effectiveness of three oncology pharmacogenomic tests currently in use in Ontario.
Evidence-based analyses have been prepared for each of these technologies. These have been completed in conjunction with internal and external stakeholders, including a Provincial Expert Panel on Pharmacogenomics (PEPP). Within the PEPP, subgroup committees were developed for each disease area. For each technology, an economic analysis was also completed by the Toronto Health Economics and Technology Assessment Collaborative (THETA) and is summarized within the reports.
The following reports can be publicly accessed at the MAS website at: www.health.gov.on.ca/mas or at www.health.gov.on.ca/english/providers/program/mas/mas_about.html
Gene Expression Profiling for Guiding Adjuvant Chemotherapy Decisions in Women with Early Breast Cancer: An Evidence-Based and Economic Analysis
Epidermal Growth Factor Receptor Mutation (EGFR) Testing for Prediction of Response to EGFR-Targeting Tyrosine Kinase Inhibitor (TKI) Drugs in Patients with Advanced Non-Small-Cell Lung Cancer: an Evidence-Based and Economic Analysis
K-RAS testing in Treatment Decisions for Advanced Colorectal Cancer: an Evidence-Based and Economic Analysis.
Objective
The objective of this systematic review is to determine the predictive value of KRAS testing in the treatment of metastatic colorectal cancer (mCRC) with two anti-EGFR agents, cetuximab and panitumumab. Economic analyses are also being conducted to evaluate the cost-effectiveness of KRAS testing.
Clinical Need: Condition and Target Population
Metastatic colorectal cancer (mCRC) is usually defined as stage IV disease according to the American Joint Committee on Cancer tumour node metastasis (TNM) system or stage D in the Duke’s classification system. Patients with advanced colorectal cancer (mCRC) either present with metastatic disease or develop it through disease progression.
KRAS (Kristen-RAS, a member of the rat sarcoma virus (ras) gene family of oncogenes) is frequently mutated in epithelial cancers such as colorectal cancer, with mutations occurring in mutational hotspots (codons 12 and 13) of the KRAS protein. Involved in EGFR-mediated signalling of cellular processes such as cell proliferation, resistance to apoptosis, enhanced cell motility and neoangiogenesis, a mutation in the KRAS gene is believed to be involved in cancer pathogenesis. Such a mutation is also hypothesized to be involved in resistance to targeted anti-EGFR (epidermal growth factor receptor with tyrosine kinase activity) treatments such as cetuximab and panitumumab, hence, the important in evaluating the evidence on the predictive value of KRAS testing in this context.
KRAS Mutation Testing in Advanced Colorectal Cancer
Both cetuximab and panitumumab are indicated by Health Canada in the treatment of patients with metastatic colorectal cancer whose tumours are WT for the KRAS gene. Cetuximab may be offered as monotherapy in patients intolerant to irinotecan-based chemotherapy or in patients who have failed both irinotecan and oxaliplatin-based regimens and who received a fluoropyrimidine. It can also be administered in combination with irinotecan in patients refractory to other irinotecan-based chemotherapy regimens. Panitumumab is only indicated as a single agent after failure of fluoropyrimidine-, oxaliplatin-, and irinotecan-containing chemotherapy regimens.
In Ontario, patients with advanced colorectal cancer who are refractory to chemotherapy may be offered the targeted anti-EGFR treatments cetuximab or panitumumab. Eligibility for these treatments is based on the KRAS status of their tumour, derived from tissue collected from surgical or biopsy specimens. It is believed that KRAS status is not affected by treatments, therefore, for patients for whom surgical tissue is available for KRAS testing, additional biopsies prior to treatment with these targeted agents is not necessary. For patients that have not undergone surgery or for whom surgical tissue is not available, a biopsy of either the primary or metastatic site is required to determine their KRAS status. This is possible as status at the metastatic and primary tumour sites is considered to be similar.
Research Question
To determine if there is predictive value of KRAS testing in guiding treatment decisions with anti-EGFR targeted therapies in advanced colorectal cancer patients refractory to chemotherapy.
Research Methods
Literature Search
The Medical Advisory Secretariat followed its standard procedures and on May 18, 2010, searched the following electronic databases: Ovid MEDLINE, EMBASE, Ovid MEDLINE In-Process & Other Non-Indexed Citations, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews and The International Network of Agencies for Health Technology Assessment database.
The subject headings and keywords searched included colorectal cancer, cetuximab, panitumumab, and KRAS testing. The search was further restricted to English-language articles published between January 1, 2009 and May 18, 2010 resulting in 1335 articles for review. Excluded were case reports, comments, editorials, nonsystematic reviews, and letters. Studies published from January 1, 2005 to December 31, 2008 were identified in a health technology assessment conducted by the Agency for Healthcare Research and Quality (AHRQ), published in 2010. In total, 14 observational studies were identified for inclusion in this EBA: 4 for cetuximab monotherapy, 7 for the cetuximab-irinotecan combination therapy, and 3 to be included in the review for panitumumab monotherapy
Inclusion Criteria
English-language articles, and English or French-language HTAs published from January 2005 to May 2010, inclusive.
Randomized controlled trials (RCTs) or observational studies, including single arm treatment studies that include KRAS testing.
Studies with data on main outcomes of interest, overall and progression-free survival.
Studies of third line treatment with cetuximab or panitumumab in patients with advanced colorectal cancer refractory to chemotherapy.
For the cetuximab-irinotecan evaluation, studies in which at least 70% of patients in the study received this combination therapy.
Exclusion Criteria
Studies whose entire sample was included in subsequent publications which have been included in this EBA.
Studies in pediatric populations.
Case reports, comments, editorials, or letters.
Outcomes of Interest
Overall survival (OS), median
Progression-free-survival (PFS), median.
Response rates.
Adverse event rates.
Quality of life (QOL).
Summary of Findings of Systematic Review
Cetuximab or Panitumumab Monotherapy
Based on moderate GRADE observational evidence, there is improvement in PFS and OS favouring patients without the KRAS mutation (KRAS wildtype, or KRAS WT) compared to those with the mutation.
Cetuximab-Irinotecan Combination Therapy
There is low GRADE evidence that testing for KRAS may optimize survival benefits in patients without the KRAS mutation (KRAS wildtype, or KRAS WT) compared to those with the mutation.
However, cetuximab-irinotecan combination treatments based on KRAS status discount any effect of cetuximab in possibly reversing resistance to irinotecan in patients with the mutation, as observed effects were lower than for patients without the mutation. Clinical experts have raised concerns about the biological plausibility of this observation and this conclusion would, therefore, be regarded as hypothesis generating.
Economic Analysis
Cost-effectiveness and budget impact analyses were conducted incorporating estimates of effectiveness from this systematic review. Evaluation of relative cost-effectiveness, based on a decision-analytic cost-utility analysis, assessed testing for KRAS genetic mutations versus no testing in the context of treatment with cetuximab monotherapy, panitumumab monotherapy, cetuximab in combination with irinotecan, and best supportive care.
Of importance to note is that the cost-effectiveness analysis focused on the impact of testing for KRAS mutations compared to no testing in the context of different treatment options, and does not assess the cost-effectiveness of the drug treatments alone.
Conclusions
KRAS status is predictive of outcomes in cetuximab and panitumumab monotherapy, and in cetuximab-irinotecan combination therapy.
While KRAS testing is cost-effective for all strategies considered, it is not equally cost-effective for all treatment options.
PMCID: PMC3377508  PMID: 23074403
24.  Antitumor Effects of EGFR Antisense Guanidine-Based Peptide Nucleic Acids in Cancer Models 
ACS chemical biology  2012;8(2):345-352.
Peptide nucleic acids have emerged over the past two decades as a promising class of nucleic acid mimics because of their strong binding affinity and sequence selectivity toward DNA and RNA, and resistance to enzymatic degradation by proteases and nucleases. While they have been shown to be effective in regulation of gene expression in vitro, and to a small extent in vivo, their full potential for molecular therapy has not yet been fully realized due to poor cellular uptake. Herein, we report the development of cell-permeable, guanidine-based peptide nucleic acids targeting the epidermal growth factor receptor (EGFR) in preclinical models as therapeutic modality for head and neck squamous cell carcinoma (HNSCC) and nonsmall cell lung cancer (NSCLC). A GPNA oligomer, 16 nucleotides in length, designed to bind to EGFR gene transcript elicited potent antisense effects in HNSCC and NSCLC cells in preclinical models. When administered intraperitoneally in mice, EGFRAS-GPNA was taken-up by several tissues including the xenograft tumor. Systemic administration of EGFRAS-GPNA induced antitumor effects in HNSCC xenografts, with similar efficacies as the FDA-approved EGFR inhibitors: cetuximab and erlotinib. In addition to targeting wild-type EGFR, EGFRAS-GPNA is effective against the constitutively active EGFR vIII mutant implicated in cetuximab resistance. Our data reveals that GPNA is just as effective as a molecular platform for treating cetuximab resistant cells, demonstrating its utility in the treatment of cancer.
doi:10.1021/cb3003946
PMCID: PMC3684443  PMID: 23113581
25.  Nuclear EGFR Contributes to Acquired Resistance to Cetuximab 
Oncogene  2009;28(43):3801-3813.
Epidermal growth factor receptor (EGFR) is a ubiquitously expressed receptor tyrosine kinase involved in the etiology of several human cancers. Cetuximab is an EGFR blocking-antibody that has been approved for the treatment of patients with cancers of the head and neck (HNSCC) and metastatic colorectal cancer (mCRC). Previous reports have shown that EGFR translocation to the nucleus is associated with cell proliferation. Here we investigated mechanisms of acquired resistance to cetuximab using a model derived from the non-small cell lung cancer line H226. We demonstrated that cetuximab-resistant cells overexpress HER family ligands including epidermal growth factor (EGF), amphiregulin (AR), heparin-binding EGF (HB-EGF) and β-cellulin. Overexpression of these ligands is associated with the nuclear translocation of the EGFR and this process was mediated by the Src family kinases (SFK). Treatment of cetuximab-resistant cells with the SFK inhibitor, dasatinib, resulted in loss of nuclear EGFR, increased membrane expression of the EGFR and re-sensitization to cetuximab. In addition, expression of a nuclear localization sequence tagged EGFR in cetuximab-sensitive cells increased resistance to cetuximab both in vitro and in mouse xenografts. Collectively, these data suggest that nuclear expression of EGFR may be an important molecular determinant of resistance to cetuximab therapy and provides a rationale for investigating nuclear EGFR as a biomarker for cetuximab response. Further, these data suggest a rationale for the design of clinical trials that examine the value of treating patients with cetuximab-resistant tumors with inhibitors of SFKs in combination with cetuximab.
doi:10.1038/onc.2009.234
PMCID: PMC2900381  PMID: 19684613
EGFR; nuclear; cetuximab; resistance; Src-family kinases; dasatinib

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