Efficacy of Cetuximab After Treatment with Oral Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitor—Based Chemotherapy in Metastatic Colorectal Cancer

Evaluation of the immune factors in the tumor environment before and after the treatment of cetuximab combined with chemotherapy

Background

The effect of chemotherapy combined with monoclonal antibodies (mAbs) on the immune state of the tumor environment remains unclear and controversial. The aim of this study is to examine the effect of chemotherapy combined with cetuximab (C225, an anti-EGFR mAb) on the immune state of tumor environment, and the correlation of that effect and the clinical efficacy.

Methods

Twelve patients with colorectal cancer, who received the treatment of chemotherapy combined with C225, were enrolled in this study. The tumor specimen of the primary colorectal cancer before and after treatment was obtained. The expression of a series of immune factors (TGF-β1, CD8, IL-2, TNF-α, and VEGF) was measured by immunochemistry. The expression of these immune factors before and after treatment was compared by the Wilcoxon signed-rank test. The correlation of the change of immune parameter expression after treatment and clinical efficacy was examined by chi-square tests. The correlation of the expression of immune factors, clinical efficacy, and treatment number was examined by the Spearman’s correlation analysis.

Results

There was no significant difference between the expression of TGF-β1 before and after the treatment (P >0.05). The change of TGF-β1 expression after treatment significantly correlated negatively with clinical efficacy (P = 0.05). As for CD8, IL-2, VEGF, and TNF-α, there were no significant differences between the expression before and after the treatment (P >0.05), and the change of expression after treatment also did not correlate significantly with clinical efficacy (P >0.05). The change of IL-2 expression after treatment significantly correlated negatively with treatment number (correlation coefficient = -0.585, P = 0.046). The change of TGF-β1 expression after treatment significantly correlated negatively with clinical efficacy (correlation coefficient = -0.684, P = 0.014). Before treatment, the expression of TNF-α significantly correlated positively with the expression of IL-2 (correlation coefficient = 0.629, P = 0.028). After treatment, the expression of TGF-β1 significantly correlated negatively with the expression of CD8 (correlation coefficient = -0.664, P = 0.019).

Conclusions

These results suggested that, in the tumor environment, the change of immune factors after treatment of cetuximab combined with chemotherapy may be associated with clinical efficacy.

Cetuximab therapy in the treatment of metastatic colorectal cancer: the future frontier?

BACKGROUND

To review the outcomes following cetuximab therapy in patients with metastatic colorectal cancer.

METHODS

Relevant articles were reviewed from the published literature using the Medline database. The search was performed using the keywords "colorectal cancer", "cetuximab", "liver metastases", "liver resection" and "hepatectomy".

RESULTS

Cetuximab was first used in the palliative setting and an increase in response rates were seen, however with no improvement in overall survival. Published data have observed that cetuximab may be beneficial as part of a down-staging programme. The addition of cetuximab to chemotherapy regimens in patients with KRAS wild-type colorectal cancer has been shown to increase the response rates and the number of patients being down-staged and offered potentially curative resection. The OPUS and CRYSTAL trials observed good response rates following the addition of cetuximab but low resection rates. The CELIM and POCHER studies reported higher resection rates due to better patient selection and study design. However, the majority of published studies tend to report minimal surgical data and lack short- and long-term outcomes.

CONCLUSION

The use of cetuximab to conventional chemotherapy regimens may improve the efficacy of down-staging programmes, leading to more patients being offered potentially curative resection.

A Markov model assessing the effectiveness and cost-effectiveness of FOLFOX compared with FOLFIRI for the initial treatment of metastatic colorectal cancer

OBJECTIVE

To analyze the efficacy and cost-effectiveness of FOLFOX compared with FOLFIRI for patients with metastatic colorectal cancer.

METHOD

We developed a Markov decision model using a hypothetical cohort of patients with metastatic colorectal cancer to compare beginning chemotherapy with FOLFOX or FOLFIRI. Probabilities of toxicities, including neutropenia, diarrhea, and neuropathy, were based on published literature for FOLFOX and FOLFIRI. Costs for physician and hospital services unadjusted for geographic location were estimated using Centers for Medicare and Medicaid services reimbursement data. Drug costs were estimated using Medicare B reimbursement and the Federal Supply Schedule. Health outcomes were measured in quality-adjusted life years (QALYs). Univariate and probabilistic sensitivity analyses were performed to address uncertainty in the model parameters.

RESULTS

The FOLFOX strategy provided 1.003 QALYs at a cost of $29,865, whereas FOLFIRI provided 0.921 QALYs at a cost of $24,551. The incremental cost-effectiveness ratio for FOLFOX treatment was $65,170/QALY. In 10,000 probabilistic Monte Carlo simulations, FOLFOX was cost-effective in 48.59% of trials using a $50,000/QALY threshold. The most influential variables in univariate sensitivity analysis were the expected years of survival associated with each chemotherapy regimen.

CONCLUSIONS

FOLFOX and FOLFIRI are similar in terms of costs and benefits. The slight QALY benefits associated with FOLFOX are within the range of $100,000/QALY, an accepted threshold in oncology.

Phase 2 study of cetuximab in patients with advanced hepatocellular carcinoma

BACKGROUND

Epidermal growth factor receptor (EGFR) and ligand expression is frequently seen in hepatocellular carcinoma (HCC). A phase 2 study was performed with cetuximab, a chimeric monoclonal antibody that binds specifically to EGFR, in patients with advanced HCC.

METHODS

Eligibility criteria included unresectable or metastatic measurable HCC, an Eastern Cooperative Oncology Group performance status <or=2, Cancer of the Liver Italian Program (CLIP) score <or=3, and adequate organ functions. The initial dose of cetuximab was 400 mg/m(2) given intravenously followed by weekly intravenous infusions at 250 mg/m(2). Each cycle was defined as 6 consecutive weekly treatments. EGFR expression was assayed by immunohistochemistry and trough serum concentrations of cetuximab were determined during the first cycle.

RESULTS

Thirty patients were enrolled and assessable for efficacy and toxicity. No responses were seen. Five patients had stable disease (median time, 4.2 months; range, 2.8-4.2 months). The median overall survival was 9.6 months (95% confidence interval [CI], 4.3-12.1 months) and the median progression-free survival (PFS) was 1.4 months (95% CI, 1.2-2.6 months). The treatment was generally well tolerated. No treatment-related grade 4-5 toxicities occurred. Grade 3 (according to the National Cancer Institute's Common Terminology Criteria for Adverse Events [version 3.0]) aspartate aminotransferase, hypomagnesemia, and fever without neutropenia were noted in 1 patient (3.3%) each. On Week 6 of Cycle 1, arithmetic mean serum cetuximab concentrations for patients with Child-Turcotte-Pugh (CTP) A and CTP B disease were 47.6 mcg/mL and 66.9 mcg/mL, respectively.

CONCLUSIONS

Although cetuximab could be safely administered with tolerable toxicity profiles, it demonstrated no antitumor activity in HCC in this phase 2 study. Cetuximab trough concentrations were not notably altered in patients with mild to moderate hepatic dysfunction.

Targeting the epidermal growth factor receptor in colorectal carcinoma

Colorectal cancer continues to be a common cause of death in this country, accounting for more than 55,000 deaths in 2006. The introduction of targeted biologic therapies, such as the epidermal growth factor receptor and tyrosine kinase inhibitors, has expanded the treatment options and has shown promise for patients with advanced disease. This article gives a history of the treatment of colorectal cancer, with a focus on the efficacy and toxicity of epidermal growth factor receptor inhibitors and their implications for the nursing community.

A Phase II study of cetuximab (Erbitux) plus FOLFIRI for irinotecan and oxaliplatin-refractory metastatic colorectal cancer

We have evaluated the efficacy and safety of cetuximab plus FOLFIRI for irinotecan and oxaliplatin-refractory colorectal cancers. From September 2004 to February 2006, 31 patients with metastatic colorectal cancer were treated with cetuximab (400 mg/m(2) intravenously [IV] over 2 hr on day 1 followed by weekly 1-hr infusions of 250 mg/m(2)) plus bi-weekly FOLFIRI (irinotecan 150 mg/m(2) IV over 90 min, and leucovorin 100 mg/m(2) IV over 2 hr, followed by 5-FU 400 mg/m(2) IV bolus on day 1, and followed by 5-FU 2,400 mg/m(2) by continuous IV over 46 hrs). Patients received a median of four cycles (range: 1-23). Eight (25.8%) patients had confirmed partial responses and 10 (32.2%) had stable disease. After a median follow-up of 13.2 months for surviving patients, the median time to progression was 2.9 months, the median duration of response was 5.4 months, and the median overall survival was 10.9 months. Skin toxicity was observed in 25 patients (80.4%) including grade 3 in 6 patients (19.4%). Other common non-hematologic toxicities of all grades were mucositis (32.3%), asthenia (22.6%), diarrhea (12.9%), and paronychial cracking (12.9%). The combination of cetuximab with FOLFIRI was effective and tolerable in colorectal cancer patients heavily pretreated with a number of chemotherapy regimens.