Cetuximab and Cisplatin for Chemotherapy-Refractory Squamous Cell Cancer of the Head and Neck

Cardio-Oncology: Cancer Therapy-related Cardiovascular Complications in a Molecular Targeted Era: New Concepts and Perspectives

Cardio-oncology is a medical discipline that identifies, prevents, and treats the cardiovascular complications related to cancer therapy. Due to the remarkable proliferation of new cancer therapies causing cardiovascular complications, such as hypertension, heart failure, vascular complications, and cardiac arrhythmia, we provide an extensive, comprehensive revision of the most up-to-date scientific information available on the cardiovascular complications associated with the use of newer, novel chemotherapeutic agents, including their reported incidence, suggested pathophysiology, clinical manifestations, potential treatment, and prevention. The authors consider this topic to be relevant for the clinicians since cardiovascular complications associated with the administration of recently approved drugs are relatively underappreciated. The purpose of this article is to provide a state-of-the-art review of cardiovascular complications associated with the use of newer, novel chemotherapeutic agents and targeted therapies, including their reported incidence, suggested pathophysiology, clinical manifestations, potential treatment, and prevention.  Ongoing efforts are needed to provide a better understanding of the frequency, mechanisms of disease, prevention, and treatment of cardiovascular complications induced by the newer, novel chemotherapeutic agents. Development of a cardio-oncology discipline is warranted in order to promote task forces aimed at the creation of oncology patient-centered guidelines for the detection, prevention, and treatment of potential cardiovascular side effects associated with newer cancer therapies.

Current Status of Cetuximab for the Treatment of Patients with Solid Tumors

Objective:

To review the pharmacology, pharmacokinetics, clinical evidence, and safety, as well as the potential directions for use, of the epidermal growth factor receptor (EGFR) monoclonal antibody cetuximab.

Data Sources:

A MEDLINE search (1966–December 2005) was conducted using the following terms: cetuximab, Erbitux, C225, epidermal growth factor receptor, and EGFR. Additional information was obtained via meeting abstracts, bibliographies from relevant articles, national guidelines, and the manufacturer.

Study Selection and Data Extraction:

Preclinical and clinical trials utilizing cetuximab in the treatment of solid tumors were selected from the data sources. All published, randomized clinical trials involving cetuximab in treatment of metastatic colorectal cancer and studies providing a description of the pharmacology, pharmacokinetics, safety, or efficacy were included in this review.

Data Synthesis:

Many solid tumors overexpress EGFR, making it an ideal target for anticancer agents. Cetuximab is the only EGFR monoclonal antibody commercially available and is approved for the treatment of EGFR-expressing, metastatic colorectal cancer in patients refractory or intolerant to irinotecan. Data on patients with other solid tumors are encouraging with cetuximab used as monotherapy or in combination with chemotherapy, radiation, or other targeted agents. Common adverse effects include dermatologic and hypersensitivity reactions.

Conclusions:

Further clinical data are necessary to clearly define the role of cetuximab in the treatment of patients with solid malignancies, with emphasis on survival and quality-of-life benefits relative to its cost.

EGFR status and EGFR ligand expression influence the treatment response of head and neck cancer cell lines

BACKGROUND

Combination treatment (chemoradiotherapy) is the standard treatment for locally advanced head and neck squamous cell carcinoma (HNSCC); however, treatment resistance and local recurrence are significant problems. A high level of epidermal growth factor receptor (EGFR) has been associated with a more aggressive phenotype as well as decreased responsiveness to radio- or chemotherapy. We examined the role of EGFR status and EGFR ligand expression for the treatment response.

METHODS

Intrinsic sensitivity to radiotherapy, cisplatin, and cetuximab treatments was investigated in 25 HNSCC cell lines. EGFR gene copy number, mRNA and protein expression, EGFR and Akt phosphorylation status, and mRNA expression of the EGFR ligands were analyzed using quantitative PCR and ELISA and assessed for their impact on treatment sensitivity.

RESULTS

Different treatment modalities yielded great diversity in outcome; of note, cetuximab treatment stimulated growth in one cell line. When treatments were combined primarily additive effects were observed. While radioresistance tended to be associated with a high level of phosphorylated EGFR (pEGFR; P = 0.09), cetuximab-resistant cells had low levels of pEGFR (P = 0.13). The three most cetuximab-sensitive cell lines had high EGFR gene copy numbers. Furthermore, cetuximab treatment response was significantly correlated with epiregulin mRNA expression (r = -0.408, P = 0.043). Cisplatin-resistant tumor cells expressed significantly lower levels of EGFR protein (P = 0.04) compared to cisplatin-sensitive cells and tended to have lower levels of phosphorylated Akt (pAkt; P = 0.13) and lower expression levels of amphiregulin (P = 0.18).

CONCLUSIONS

Epidermal growth factor receptor status and ligand expression influence the treatment sensitivity of HNSCC cells and may be useful as predictive markers.

Cetuximab in the treatment of squamous cell carcinoma of the head and neck

The majority of the head and neck cancers are squamous cell carcinomas, which commonly overexpress the EGF receptor (EGFR). Cetuximab is a chimeric monoclonal antibody that binds with high affinity to the extracellular domain of EGFR, and in addition induces antibody-dependent cellular cytoxicity. In a randomized Phase III trial in patients with locoregionally advanced squamous cell carcinoma of the head and neck, the addition of cetuximab to radiotherapy prolonged the median time of locoregional control from 14.9 to 24.4 months and increased the median overall survival from 29.3 to 49.0 months. In patients with platinum-refractory recurrent and/or metastatic disease, the objective response and disease-control rates in various studies ranged from 10 to 13% and from 46 to 56%, respectively. In the EXTREME trial, the addition of cetuximab to platinum/5-fluorouracil as first-line treatment of recurrent/metastatic squamous cell carcinoma of the head and neck not only led to significant improvements in survival, response rate and disease control, but also induced a better symptom control in comparison with that observed with platinum/5-fluorouracil alone.

Epidermal growth factor receptor inhibition and non-small cell lung cancer

The majority of non-small cell (NSC) lung cancers express epidermal growth factor receptor (EGFR). Many studies have evaluated the clinical effect from targeted therapy achieved by blocking EGFR in patients with NSC lung cancer. Treatment of biologically unselected patients with NSC lung cancer with two reversible quinazole EGFR inhibitors, gefitinib and erlotinib, gave negative results in all controlled trials but one. Ten percent to 20% of patients with NSC lung cancers have somatic mutations in EGFR, and these patients have a significantly higher response rate (73%) to treatment with EGFR inhibitors than patients with wild-type EGFR (10%). Patients with Asian background, women, non-smokers, and patients with adenocarcinoma had higher response rates than other patients, and the differences may be due to an association between the clinical characteristics and EGFR mutations. Further studies are needed to fully evaluate the effect of EGFR inhibitor-treatment for subgroups of patients with NSC lung cancer with favorable biological and clinical characteristics.

Increased epidermal growth factor receptor gene copy number is associated with poor prognosis in head and neck squamous cell carcinomas

PURPOSE

High epidermal growth factor receptor (EGFR) gene copy number is associated with poor prognosis in lung cancer, but such findings have not been reported for HNSCC. A better understanding of the EGFR pathway may improve the use of EGFR inhibitors in HNSCC.

PATIENTS AND METHODS

EGFR status was analyzed in 86 tumor samples from 82 HNSCC patients by fluorescent in situ hybridization (FISH) to determine EGFR gene copy number, by polymerase chain reaction and direct sequencing for activating mutations, and by DNA microarray and immunohistochemistry for RNA and protein expression. The results were associated with patient characteristics and clinical end points.

RESULTS

Forty-three (58%) of 75 samples with FISH results demonstrated EGFR high polysomy and/or gene amplification (FISH positive). The FISH-positive group did not differ from the FISH-negative group with respect to age, sex, race, tumor grade, subsites and stage, or EGFR expression by analyses of RNA or protein. No activating EGFR mutations were found. However, the FISH-positive group was associated with worse progression-free and overall survival (P < .05 and P < .01, respectively; log-rank test). When microarray data were interrogated using the FISH results as a supervising parameter, ECop (which is known to coamplify with EGFR and regulate nuclear factor-kappa B transcriptional activity) had higher expression in FISH-positive tumors.

CONCLUSION

High EGFR gene copy number by FISH is frequent in HNSCC and is a poor prognostic indicator. Additional investigation is indicated to determine the biologic significance and implications for EGFR inhibitor therapies in HNSCC.

Cetuximab in squamous cell carcinoma of the head and neck

Surgery and radiotherapy are the standard treatment options for patients with squamous cell carcinoma of the head and neck (SCCHN). Chemotherapy and chemoradiotherapy are new alternatives for locally advanced disease, particularly induction chemotherapy for patients with unresectable tumors. In recurrent/metastatic disease and after progression to platin-based regimens, no treatments other than best supportive care are currently available. Most SCCHN tumors overexpress the epidermal growth factor receptor (EGFR). This is a tyrosine kinase membrane receptor and has a clear implication in angiogenesis, tumor progression and resistance to different cancer treatments. Cetuximab is a monoclonal antibody that binds to EGFR and alters the tyrosine kinase-mediated signal transduction pathway. The drug is active in colon cancer and is currently being tested in SCCHN patients. For locally advanced disease, cetuximab/radiotherapy combination has demonstrated a benefit in survival when compared with radiotherapy alone as radical treatment. Cetuximab is an active treatment in platin-refractory patients with recurrent/metastatic disease.

Adverse effects of the humanized antibodies used as cancer therapeutics

PURPOSE OF REVIEW

Humanized monoclonal antibodies represent a recent and very significant addition to the anticancer armamentarium. With improved therapeutic strategies due to these agents, however, there are also various, sometimes unexpected, side effects.

RECENT FINDINGS

Most of the monoclonal antibodies used in oncology share a risk of infusion-related manifestations, including the possibility of anaphylaxis; these reactions usually appear early on during the first administration. Hematological toxicity is also frequent, especially if the antibodies are associated with chemotherapy; the resulting neutropenia--and with some agents lymphopenia--is associated with an increased risk of infection. Cardiac failure and pulmonary complications have been reported with some of these agents, especially in patients with prior cardiac or pulmonary comorbidities.

SUMMARY

Although consideration of these side effects is important in terms of prevention and therapy, overall they are relatively uncommon, making therapy with monoclonal antibodies quite safe in comparison with other therapeutic modalities used in cancer patients.

Expression of epidermal growth factor receptor in squamous cell carcinomas of the anal canal is independent of gene amplification

Immunohistochemical detection of expression of the epidermal growth factor receptor (EGFR) has been utilized to identify eligible patients with solid malignant tumors, including colorectal adenocarcinoma, for monoclonal antibody therapy (eg, cetuximab). The EGFR status in squamous cell carcinoma of the anal canal, an uncommon malignancy traditionally treated with chemoradiation, has not been well investigated. In this study, 38 primary squamous cell carcinomas of the anal canal were immunohistochemically examined for EGFR expression and analyzed by fluorescence in situ hybridization (FISH) for EGFR gene copy numbers. The results showed a variable degree of EGFR expression in 21 (55%) tumors, among which 13 (62%) cases exhibited a 2+ to 3+ staining pattern according to the Dako EGFR phamDx interpretation guide. There were no significant differences among tumors stratified by stage, degree of keratinization, or tissue block storage times. FISH analysis showed that none of the 34 cases with interpretable results had EGFR gene amplification. Increased gene copy numbers due to polysomy 7 were seen in seven of 18 (39%) cases that expressed EGFR protein and four of 16 (25%) cases that did not (P=0.3876). Ten (56%) tumors with positive EGFR staining showed a balanced disomy 7 pattern and one case with monosomy 7 exhibited strong EGFR expression (3+). These results demonstrate that EGFR is overexpressed in more than one-half of the squamous cell carcinomas of the anal canal through mechanisms other than gene amplification. These observations may have important therapeutic implications since EGFR-based targeted therapies have shown promise for other malignant neoplasms.