Christiane Langer

EPIC: Phase III Trial of Cetuximab Plus Irinotecan After Fluoropyrimidine and Oxaliplatin Failure in Patients With Metastatic Colorectal Cancer

PURPOSE To determine whether adding cetuximab to irinotecan prolongs survival in patients with metastatic colorectal cancer (mCRC) previously treated with fluoropyrimidine and oxaliplatin. PATIENTS AND METHODS This multicenter, open-label, phase III study randomly assigned 1,298 patients with epidermal growth factor receptor-expressing mCRC who had experienced first-line fluoropyrimidine and oxaliplatin treatment failure to cetuximab (400 mg/m(2) day 1 followed by 250 mg/m(2) weekly) plus irinotecan (350 mg/m(2) every 3 weeks) or irinotecan alone. Primary end point was overall survival (OS); secondary end points included progression-free survival (PFS), response rate (RR), and quality of life (QOL). RESULTS Median OS was comparable between treatments: 10.7 months (95% CI, 9.6 to 11.3) with cetuximab/irinotecan and 10.0 months (95% CI, 9.1 to 11.3) with irinotecan alone (hazard ratio [HR], 0.975; 95% CI, 0.854 to 1.114; P = .71). This lack of difference may have been due to post-trial therapy: 46.9% of patients assigned to irinotecan eventually received cetuximab (87.2% of those who did, received it with irinotecan). Cetuximab added to irinotecan significantly improved PFS (median, 4.0 v 2.6 months; HR, 0.692; 95% CI, 0.617 to 0.776; P <or= .0001) and RR (16.4% v 4.2%; P < .0001), and resulted in significantly better scores in the QOL analysis of global health status (P = .047). Cetuximab did not exacerbate toxicity, except for acneform rash, diarrhea, hypomagnesemia, and associated electrolyte imbalances. Neutropenia was the most common severe toxicity across treatment arms. CONCLUSION Cetuximab and irinotecan improved PFS and RR, and resulted in better QOL versus irinotecan alone. OS was similar between study groups, possibly influenced by the large number of patients in the irinotecan arm who received cetuximab and irinotecan poststudy.

Primary tumor location as a prognostic factor in metastatic colorectal cancer.

BACKGROUND We sought to clarify the prognostic impact of primary tumor location in metastatic colorectal cancer (mCRC). METHODS We evaluated the association between tumor location and survival parameters in patients with previously untreated mCRC receiving first-line chemotherapy ± bevacizumab in three independent cohorts: a prospective pharmacogenetic study (PROVETTA) and two randomized phase III trials, AVF2107g and NO16966. Cancers proximal or distal of the splenic flexure were classified as right-sided or left-sided, respectively. The primary end point was overall survival (OS). Data were analyzed with Cox proportional hazards and logistic regression models. All statistical tests were two-sided. RESULTS Among evaluable patients in the PROVETTA (n = 200), AVF2107g (n = 559), and NO16966 (n = 1268) studies, 72.0%, 63.1%, and 73.7% had left-sided tumors, respectively. In PROVETTA, patients with left-sided tumors had superior OS (left-sided vs right-sided: hazard ratio [HR] = .44, 95% confidence interval [CI] = .28 to .70, P < .001) and progression-free survival (HR = .52, 95% CI = .36 to .75, P < .001) outcomes. Multivariable analyses confirmed right-sided location as a negative prognostic variable, independent of mucinous histology and BRAF mutational status. Data from the AVF2107g (HR for OS = .55, 95% CI = .43 to .70) and NO16966 trials (HR for OS = .71, 95% CI = .62 to .82 both P < .001) also showed favorable outcomes in patients with left-sided tumors. In both randomized studies, the efficacy of bevacizumab was independent of tumor location. CONCLUSIONS These data demonstrate that primary tumor location is an important prognostic factor in previously untreated mCRC. Given the consistency across an exploratory set and two confirmatory phase III studies, side of tumor origin should be considered for stratification in randomized trials.

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.

Phase I and Pharmacokinetic Study of Cetuximab and Irinotecan in Children With Refractory Solid Tumors: A Study of the Pediatric Oncology Experimental Therapeutic Investigators' Consortium

PURPOSE To determine the dose of cetuximab that can be safely combined with irinotecan for treatment of pediatric and adolescent patients with refractory solid tumors. PATIENTS AND METHODS This open-label, phase I study enrolled patients ages 1 to 18 years with advanced refractory solid tumors, including tumors of the CNS. Patient cohorts by age group (children, ages 1 to 12 years; adolescents, ages 13 to 18 years) received escalating weekly doses of cetuximab (75, 150, 250 mg/m(2)) in a 3 + 3 design, plus irinotecan (16 or 20 mg/m(2)/d) for 5 days for 2 consecutive weeks every 21 days. The primary end points were establishing the maximum-tolerated dose (MTD), recommended phase II dose (RPIID), and pharmacokinetics of the combination. Preliminary safety and efficacy data were also collected. RESULTS Twenty-seven children and 19 adolescents received a median of 7.1 and 6.0 weeks of cetuximab therapy, respectively. Cetuximab 250 mg/m(2) weekly plus irinotecan 16 mg/m(2)/d (pediatric) or 20 mg/m(2)/d (adolescent) have been established as the MTD/RPIID. Dose-limiting toxicities included diarrhea and neutropenia. Mild to moderate (grade 1 to 2) acneiform rash occurred in a majority of patients; no grade 3 to 4 rashes were observed. Cetuximab demonstrated dose-dependent clearance in both children and adolescents, similar to that in adults. There were two confirmed partial responses, both in patients with CNS tumors. Stable disease was achieved in 18 patients overall, including 10 patients with CNS tumors (38.5%). CONCLUSION The cetuximab/irinotecan combination can be given safely to children and adolescents with cancer. Promising activity, particularly in CNS tumors, warrants phase II evaluation of this regimen.

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

Purpose: The insulin-like growth factor 1 (IGF1) signaling pathway is an important growth-regulatory pathway, which plays a crucial role in colorectal cancer (CRC) proliferation, differentiation, migration, angiogenesis, and apoptosis. Previous studies showed that hyperactivation of the IGF1 receptor (IGF1R) may result in resistance to anti–epidermal growth factor receptor–targeted treatment. We tested whether germline variations within the IGF1 pathway are associated with clinical outcome in wild-type (wt) KRAS drug-refractory metastatic CRC (mCRC) patients who were treated with cetuximab monotherapy (IMC-0144). Experimental Design: Formalin-fixed, paraffin-embedded (FFPE) tissue samples of 130 drug-refractory mCRC patients enrolled in IMC-0144, a phase II clinical trial of cetuximab monotherapy, were analyzed. gDNA was extracted from dissected FFPE tumor tissue, and KRAS mutation status and six potentially functional IGF1 and IGF1R polymorphisms were analyzed using direct DNA sequencing or PCR-RFLP. Tumor response analysis was based on recursive partitioning, and survival analyses were based on univariate and multivariate hazard regression models. Results: In univariate and multivariate analyses, five IGF pathway single-nucleotide polymorphisms were significantly associated with progression-free survival (PFS) and/or overall survival (OS). In multivariate combined risk allele analysis, the additive model for PFS and OS was significantly associated with the number of risk alleles in wt KRAS patients (P = 0.001 and P = 0.02, respectively). In addition, wt KRAS patients harboring IGF1 rs2946834 A/A genotype had a 50% objective response rate compared with 0% for A/G genotype. Conclusions: These results indicate that IGF1 pathway polymorphisms are potential predictive/prognostic molecular markers for cetuximab efficacy in wt KRAS mCRC patients. Prospective biomarker-embedded clinical trials are warranted to validate our findings. Clin Cancer Res; 16(22); 5591–602. ©2010 AACR.