David J. Mauro

Expression of Epiregulin and Amphiregulin and K-ras Mutation Status Predict Disease Control in Metastatic Colorectal Cancer Patients Treated With Cetuximab

PURPOSE The antiepidermal growth factor receptor (EGFR) antibody cetuximab shows activity in multiple epithelial tumor types; however, responses are seen in only a subset of patients. This study was conducted to identify markers that are associated with disease control in patients treated with cetuximab. PATIENTS AND METHODS One hundred ten patients with metastatic colorectal cancer were enrolled onto a cetuximab monotherapy trial. Transcriptional profiling was conducted on RNA from mandatory pretreatment metastatic biopsies to identify genes whose expression correlates with best clinical responses. EGFR and K-ras mutation analyses and EGFR gene copy number analyses were performed on DNA from pretreatment biopsies. RESULTS Gene expression profiles showed that patients with tumors that express high levels of the EGFR ligands epiregulin and amphiregulin are more likely to have disease control with cetuximab (EREG, P = .000015; AREG, P = .000025). Additionally, patients whose tumors do not have K-ras mutations have a significantly higher disease control rate than patients with K-ras mutations (P = .0003). Furthermore, patients with tumors that have high expression of EREG or AREG also have significantly longer progression-free survival (PFS) than patients with low expression (EREG: P = .0002, hazard ratio [HR] = 0.47, and median PFS, 103.5 v 57 days, respectively; AREG: P < .0001, HR = 0.44, and median PFS, 115.5 v 57 days, respectively). CONCLUSION Patients with tumors that have high gene expression levels of epiregulin and amphiregulin and patients with wild-type K-ras are more likely to have disease control on cetuximab treatment. The identified markers could be developed further to select patients for cetuximab therapy.

Cetuximab-Induced Anaphylaxis and IgE Specific for Galactose-α-1,3-Galactose

BACKGROUND Cetuximab, a chimeric mouse-human IgG1 monoclonal antibody against the epidermal growth factor receptor, is approved for use in colorectal cancer and squamous-cell carcinoma of the head and neck. A high prevalence of hypersensitivity reactions to cetuximab has been reported in some areas of the United States. METHODS We analyzed serum samples from four groups of subjects for IgE antibodies against cetuximab: pretreatment samples from 76 case subjects who had been treated with cetuximab at multiple centers, predominantly in Tennessee, Arkansas, and North Carolina; samples from 72 control subjects in Tennessee; samples from 49 control subjects with cancer in northern California; and samples from 341 female control subjects in Boston. RESULTS Among 76 cetuximab-treated subjects, 25 had a hypersensitivity reaction to the drug. IgE antibodies against cetuximab were found in pretreatment samples from 17 of these subjects; only 1 of 51 subjects who did not have a hypersensitivity reaction had such antibodies (P<0.001). IgE antibodies against cetuximab were found in 15 of 72 samples (20.8%) from control subjects in Tennessee, in 3 of 49 samples (6.1%) from northern California, and in 2 of 341 samples (0.6%) from Boston. The IgE antibodies were shown to be specific for an oligosaccharide, galactose-alpha-1,3-galactose, which is present on the Fab portion of the cetuximab heavy chain. CONCLUSIONS In most subjects who had a hypersensitivity reaction to cetuximab, IgE antibodies against cetuximab were present in serum before therapy. The antibodies were specific for galactose-alpha-1,3-galactose.

Multicenter Phase II and Translational Study of Cetuximab in Metastatic Colorectal Carcinoma Refractory to Irinotecan, Oxaliplatin, and Fluoropyrimidines

PURPOSE This multicenter study evaluated the antitumor activity of cetuximab, an immunoglobulin G1 antibody directed at the epidermal growth factor receptor (EGFR), in metastatic colorectal carcinoma (CRC) refractory to irinotecan, oxaliplatin, and a fluoropyrimidine. It also evaluated the safety, pharmacokinetics, immunokinetics, and biologic determinants of activity. PATIENTS AND METHODS Patients with metastatic CRC, whose tumors demonstrated EGFR immunostaining and were refractory to irinotecan, oxaliplatin, and fluoropyrimidines, were treated with cetuximab at a loading dose of 400 mg/m2 followed by 250 mg/m2 weekly. An independent review committee (IRC) reviewed responses. Blood was collected for cetuximab pharmacokinetics and to detect antibodies to cetuximab. EGFR gene sequencing of the tyrosine kinase domain and gene copy number assessments were performed. RESULTS The response rates in 346 patients, as determined by the investigators and IRC, were 12.4% (95% CI, 9.1 to 16.4) and 11.6% (95% CI, 8.4 to 16.4). The median progression-free survival (PFS) and survival times were 1.4 months (95% CI, 1.4 to 2.1) and 6.6 months (95% CI, 5.6 to 7.6), respectively. An acneiform rash occurred in 82.9% of patients; grade 3 rash was observed in 4.9%. Response and survival related strongly to the severity of the rash. In contrast, clinical benefit did not relate to EGFR immunostaining. EGFR tyrosine kinase domain mutations were not identified, and EGFR gene copy number did not relate to response or PFS, but to survival (P = .03). CONCLUSION Cetuximab is active and well tolerated in metastatic CRC refractory to irinotecan, oxaliplatin, and fluoropyrimidines. The severity of rash was related to efficacy. Neither EGFR kinase domain mutations nor EGFR gene amplification appear to be essential for response to cetuximab in this setting.

Impact and Management of Skin Toxicity Associated with Anti-Epidermal Growth Factor Receptor Therapy: Survey Results

Biologic agents targeting the epidermal growth factor receptor (EGFR) have emerged as a robust treatment option for various solid tumors. Despite lower systemic side effects than conventional chemotherapy, the majority of patients treated with these agents experience cutaneous toxicities, including papulopustular rashes, hair and nail changes, xerosis and pruritus, which have a significant impact on health and quality of life. Currently no consensus or management guidelines exist for these untoward events. Therefore, a retrospective survey was carried out across 110 oncology practioners in the US that were administering EGFR inhibitors. Providers were queried on the impact and management of these untoward events in their practices. Responses suggest that combination therapies (topical and oral) were more effective than either therapy alone, and also lead to a more rapid resolution of the papulopustular rash. Providers also reported that patients frequently complained of physical symptoms associated with the rash (itching and pain), and that they had a positive perception when being treated for their cutaneous side effects. The survey results support that attentive cutaneous care is important in patients treated with EGFR inhibitors, and that proactive/combined interventions may enhance quality of life and optimize consistent drug administration.

Polymorphisms in Cyclooxygenase-2 and Epidermal Growth Factor Receptor Are Associated with Progression-Free Survival Independent of K-ras in Metastatic Colorectal Cancer Patients Treated with Single-Agent Cetuximab

Purpose: Recently, an objective response rate of 12% was reported in a phase II study of cetuximab in patients with epidermal growth factor receptor (EGFR)-expressing metastatic colorectal cancer (mCRC) refractory to fluoropyrimidine-, oxaliplatin-, and irinotecan-based chemotherapy (IMC-0144). In this large molecular correlates study, we tested whether K-ras mutation status and polymorphisms in genes involved in the EGFR-signaling pathway were associated with clinical outcome in IMC-0144. Experimental Design: We analyzed all available tissue samples from 130 of 346 mCRC patients enrolled in the IMC-0144 phase II clinical trial of cetuximab. Genomic DNA was extracted from formalin-fixed paraffin-embedded tumor tissues, and K-ras mutation status and the genotypes were analyzed using PCR-RFLP, direct DNA-sequencing, and 5′-end [γ-33P] ATP–labeled PCR-protocols. Results: The PFS of patients with cyclooxygenase-2 (COX-2) −765 G>C [C/C; risk ratio (RR), 0.31; 95% confidence interval (95% CI), 0.12-0.84; P = 0.032], COX-2 +8473 T>C (C/C; RR, 0.67; 95% CI, 0.40-1.13; P = 0.003), EGF +61 A>G (G/G; RR, 0.57; 95% CI, 0.34-0.95; P = 0.042), and EGFR +497 G>A (A/G; RR, 0.82; 95% CI, 0.56-1.20; P = 0.017) genotypes was significantly longer compared with those with other genotypes. In addition, patients whose tumors did not have K-ras mutations showed better RR, PFS, and overall survival than patients with K-ras mutations. In multivariable analysis, COX-2 +8473 T>C (adjusted P = 0.013) and EGFR +497 G>A (adjusted P = 0.010) remained significantly associated with progression-free survival, independent of skin rash toxicity, K-ras mutation status, and Eastern Cooperative Group performance status. Conclusions: Polymorphisms in COX-2 and EGFR may be useful independent molecular markers to predict clinical outcome in patients with mCRC treated with single-agent cetuximab, independent of skin rash toxicity, K-ras mutation, and Eastern Cooperative Oncology Group performance status.

A Phase 1 Escalating Single-Dose and Weekly Fixed-Dose Study of Cetuximab: Pharmacokinetic and Pharmacodynamic Rationale for Dosing

Purpose: This phase 1 study evaluated the pharmacokinetic and pharmacodynamic effects of cetuximab on patients with epithelial malignancies. Experimental Design: Following a skin and tumor biopsy, patients with advanced epithelial malignancies were randomized to receive a single dose of cetuximab at 50, 100, 250, 400, or 500 mg/m2 i.v. Repeat skin (days 2, 8, 15, and 22) and tumor (day 8) biopsies were obtained. Immunohistochemical expression of epidermal growth factor receptor (EGFR) and its pathway members was done on biopsies. Blood samples were obtained over 22 days for pharmacokinetic analyses. After day 22, all patients received weekly 250 mg/m2 cetuximab until disease progression or unacceptable toxicity. Results: Thirty-nine patients enrolled. Rash was noted in 26 (67%) patients. Three patients (two with colon cancer and one with laryngeal cancer) achieved a partial response and 13 patients had stable disease. Pharmacokinetic data revealed mean maximum observed cetuximab concentrations and mean area under the concentration-time curve from time zero to infinity increased in a dose-dependent manner up to 400 mg/m2 cetuximab. Mean clearance was similar at cetuximab doses ≥100 mg/m2, supporting saturation of EGFR binding at 250 mg/m2. Pharmacodynamic evaluation revealed that patients with partial response/stable disease had a higher-grade rash and higher cetuximab trough levels than those with progressive disease (P = 0.032 and 0.002, respectively). Administration of single doses (250-500 mg/m2) of cetuximab resulted in a dose-dependent decrease in EGFR protein expression levels in skin over time, supporting a minimal dose of cetuximab at 250 mg/m2 for a pharmacodynamic effect. Conclusion: This study provides a pharmacokinetic and pharmacodynamic rationale for the dosing of cetuximab.

Pharmacokinetics of Cetuximab After Administration of Escalating Single Dosing and Weekly Fixed Dosing in Patients with Solid Tumors

Purpose: Previous studies of cetuximab pharmacokinetics did not fully characterize its elimination phase. The purpose of this trial was to evaluate the pharmacokinetics of cetuximab given as a single dose followed by weekly fixed repeated dosing in patients with solid tumors. Experimental Design: Patients were randomly assigned to treatment with a single 2-hour infusion of cetuximab at doses of 50, 100, 250, 400, or 500 mg/m2 followed 3 weeks later by weekly 1-hour infusions of cetuximab at a fixed dose of 250 mg/m2. Extended pharmacokinetic sampling was collected through 504 hours after the first drug administration. Trough samples were obtained before each fixed weekly dose. Single and multidose pharmacokinetic variables were correlated with clinical outcomes. Results: Forty patients were enrolled. Pharmacokinetic analysis confirmed previous reports of nonlinear pharmacokinetics for cetuximab. Modeling studies predicted a 90% saturation of clearance at a dose of 260 mg/m2. Analyses of weekly trough concentrations indicated a slight accumulation of drug concentrations following repeated weekly dosing. Correlative studies indicated a significant association between cetuximab clearance and both body surface area (P = 0.002) and weight (P = 0.002). The occurrence of rash was significantly associated with disease stability (P < 0.002) but not with cetuximab pharmacokinetic variables. Conclusions: Pharmacokinetic results support using body surface area or weight in calculating individual cetuximab doses. A weekly dose of 250 mg/m2 is predicted to nearly fully saturate cetuximab clearance and, by inference, epidermal growth factor receptors. The association between rash and disease stability supports further prospective studies of this relationship.

Incidence and costs of treatment-related complications among patients with advanced squamous cell carcinoma of the head and neck.

OBJECTIVE To evaluate the incidence and costs of complications due to radiotherapy alone vs platinum-based chemoradiotherapy among patients diagnosed as having advanced squamous cell carcinoma of the head and neck (ASCCHN) from a payer perspective. DESIGN Retrospective cohort study. SETTING Data from the PharMetrics Patient-Centric Database from June 2000 through June 2006. PATIENTS The study included patients with ASCCHN and an indication of a secondary malignant neoplasm (both identified based on International Classification of Diseases, Ninth Revision, Clinical Modification, diagnosis codes), 124 of whom were treated with radiotherapy alone and 77 of whom were treated with chemoradiotherapy (including 53 with cisplatin plus radiotherapy, 26 with carboplatin plus radiotherapy, and 2 with cisplatin and carboplatin plus radiotherapy). The patients were assigned to 1 of 2 cohorts based on treatment type-radiotherapy only and platinum-based chemoradiotherapy-and were followed up for 6 months. MAIN OUTCOME MEASURES Incidence and costs of treatment-related complications associated with chemotherapy in ASCCHN. RESULTS We found significantly (P < .001) higher rates of treatment-related complications among patients receiving chemoradiotherapy (86%) than among patients receiving only radiotherapy (51%). The mean per-patient costs associated with treatment-related complications were approximately

Tumor necrosis factor-alpha and interleukin-1 antagonists alleviate inflammatory skin changes associated with epidermal growth factor receptor antibody therapy in mice.

10 000 higher among patients who received chemoradiotherapy than among those treated with radiotherapy alone (P < .001). These costs represented 17% of the total costs during follow-up for patients who received chemoradiotherapy and 11% of costs for those who received radiotherapy. The most expensive complications were dehydration and/or electrolyte imbalance and oral complications. CONCLUSIONS Our study results suggest that the attributable incidence and costs of treatment-related complications associated with chemotherapy in ASCCHN are substantial. The emergence of safer treatments may have the advantage of alleviating this cost burden.

Germline Polymorphisms in Genes Involved in the IGF1 Pathway Predict Efficacy of Cetuximab in Wild-type KRAS mCRC Patients

Cancer patients receiving epidermal growth factor receptor (EGFR) antibody therapy often experience an acneiform rash of uncertain etiology in skin regions rich in pilosebaceous units. Currently, this condition is treated symptomatically with very limited, often anecdotal success. Here, we show that a monoclonal antibody targeting murine EGFR, ME1, caused a neutrophil-rich hair follicle inflammation in mice, similar to that reported in patients. This effect was preceded by the appearance of lipid-filled hair follicle distensions adjacent to enlarged sebaceous glands. The cytokine tumor necrosis factor-alpha (TNFalpha), localized immunohistochemically to this affected region of the pilosebaceous unit, was specifically up-regulated by ME1 in skin but not in other tissues examined. Moreover, skin inflammation was reduced by cotreatment with the TNFalpha signaling inhibitor, etanercept, indicating the involvement of TNFalpha in this inflammatory process. Interleukin-1, a cytokine that frequently acts in concert with TNFalpha, is also involved in this process given the efficacy of the interleukin-1 antagonist Kineret. Our results provide a mechanistic framework to develop evidence-based trials for EGFR antibody-induced skin rash in patients with cancer.