title: Association of epidermal growth factor receptor polymorphism, skin toxicity, and outcome in patients with squamous cell carcinoma of the head and neck receiving cetuximab-docetaxel treatment.
abstract: OBJECTIVE
  Cetuximab, a monoclonal antibody targeting epidermal growth factor receptor (EGFR), has shown clinical efficacy in squamous cell carcinoma of the head and neck with prolonged progression-free (PFS) and overall survival (OS). In this study, we analyzed whether cetuximab-induced skin rash was correlated with distinct polymorphisms within the EGFR gene known to modulate EGFR expression, ligand binding, or signaling activity.
  
  
  METHODS
  Fifty-one patients enrolled in a single-arm phase II multicenter study for second-line treatment of recurrent or metastatic squamous cell carcinoma of the head and neck with cetuximab/docetaxel were genotyped for two genetic variations in the EGFR gene, a point substitution G-->A in exon 13 resulting in an amino acid substitution in position 521 (EGFR-R521K) and a CA repeat (CA-SSR) polymorphism in intron 1. Association between genotypes and incidence/grade of skin rash was determined by Fisher's exact test. The predictive value of genotypes for PFS and OS was determined using the log-rank test.
  
  
  RESULTS
  Overall, 21 patients (41%) developed skin rash with grade >1 within 6 weeks of treatment. The common EGFR-R521K genotype (G/G) was significantly associated with increased skin toxicity (P = 0.024) and showed a trend toward reduced risk of tumor progression (hazard ratio, 0.55; 95% confidence interval, 0.27-1.08; P = 0.08), whereas no correlation of the EGFR-R521K genotype with OS could be observed (P = 0.20). No significant interaction between CA-SSR polymorphism and skin toxicity, PFS, or OS could be detected.
  
  
  CONCLUSIONS
  Our study revealed an influence of the EGFR-R521K genotype on skin toxicity and suggested its relation to clinical activity of cetuximab/docetaxel treatment.
authors.affiliation: Department of Hematology and Oncology, Campus Benjamin Franklin and Laboratory for Translational Radiobiology & Radiooncology, Charité-Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Konrad
authors.initials: K
authors.lastname: Klinghammer
authors.forename: Maren
authors.initials: M
authors.lastname: Knödler
authors.forename: Alexander
authors.initials: A
authors.lastname: Schmittel
authors.forename: Volker
authors.initials: V
authors.lastname: Budach
authors.forename: Ulrich
authors.initials: U
authors.lastname: Keilholz
authors.forename: Ingeborg
authors.initials: I
authors.lastname: Tinhofer
mesh_terms: D000911:Antibodies, Monoclonal / Q000008:administration & dosage / Q000009:adverse effects*; D061067:Antibodies, Monoclonal, Humanized; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000009:adverse effects / Q000627:therapeutic use; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy* / Q000235:genetics*; D000068818:Cetuximab; D018572:Disease-Free Survival; D000077143:Docetaxel; D005076:Exanthema / Q000139:chemically induced* / Q000235:genetics*; D005260:Female; D018773:Genes, erbB-1; D006258:Head and Neck Neoplasms / Q000188:drug therapy* / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic; D016019:Survival Analysis; D043823:Taxoids / Q000008:administration & dosage / Q000009:adverse effects; D016896:Treatment Outcome
chemical_list: D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D043823:Taxoids; D000077143:Docetaxel; D000068818:Cetuximab