3017 POSTER Cetuximab dose-escalation in patients (pts) with metastatic colorectal cancer (mCRC) with no or slight skin reactions on standard treatment: pharmacokinetic (PK), pharmacodynamic (PD) and efficacy data from the EVEREST study

Panitumumab in colorectal cancer

The combination of chemotherapy and targeted therapies is rapidly becoming the standard of care in the treatment of metastatic colorectal cancer. Panitumumab (formerly ABX-EGF) is a fully human antibody developed to target the human epidermal growth factor receptor (EGFR/HER-1), which is expressed in up to 75% of patients with colorectal cancer. As a fully human antibody, panitumumab can be administered without any premedication and few infusion reactions have been reported. It has recently been approved in the USA for the treatment of colorectal cancer as a single agent in the salvage setting. Ongoing studies are being performed to determine whether the addition of panitumumab to standard treatment for metastatic colorectal cancer will improve the survival of these patients.

Controversies in antiepidermal growth factor receptor therapy in metastatic colorectal cancer

The randomized first-line trials, including the CRYSTAL trial, the OPUS trial, and the PRIME trial, have demonstrated the significant efficacy of cetuximab or panitumumab in patients with v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) wild-type tumors. The addition of an antiepidermal growth factor receptor (anti-EGFR)-directed monoclonal antibody to chemotherapy for these patients significantly improved progression-free survival, response rates, and R0 resection rates to a greater extent than overall survival compared with patients who received chemotherapy alone. However, 2 recent randomized phase 3 trials, the MRC COIN trial and the Nordic VII trial, reported an unexpected lack of benefit from the addition of cetuximab to chemotherapy in the first-line setting. In addition, recent retrospective analyses performed on a pooled data set from major clinical trials added more complexity, reporting an unexpected association of KRAS G13D mutation with a better clinical outcome compared with patients who had other KRAS mutations in the first-line and salvage settings, whereas the other independent analysis failed to demonstrate a benefit from panitumumab in patients with the same KRAS G13D mutation. The anti-EGFR monoclonal antibody-associated skin toxicity and the controversial strategies of management also are discussed. In this review, the authors analyze the previous randomized clinical trials and more critically re-evaluate recent trials and subgroup analyses to derive 3 factors that need to be taken into consideration regarding the addition of EGFR-directed monoclonal antibodies to chemotherapy: the preclinical data on mechanisms of action between chemotherapy and anti-EGFR antibodies along with mechanisms of resistance to anti-EGFR antibodies, the role of cross-over events in overall survival data, and the significant dose reductions of chemotherapeutic agents when combined with anti-EGFR agents.

Correlation of bevacizumab-induced hypertension and outcome in the BOXER study, a phase II study of capecitabine, oxaliplatin (CAPOX) plus bevacizumab as peri-operative treatment in 45 patients with poor-risk colorectal liver-only metastases unsuitable for upfront resection

Background:

Bevacizumab is commonly used in combination with chemotherapy in the treatment of metastatic colorectal cancer, but to date, despite extensive research, no predictive or prognostic biomarkers for bevacizumab have been identified. The development of bevacizumab-induced arterial hypertension has recently been suggested as a potential predictive biomarker.

Methods:

Blood pressure was recorded during the BOXER study, a phase II study of capecitabine, oxaliplatin (CAPOX) plus bevacizumab as peri-operative treatment in 45 patients with poor-risk colorectal liver-only metastases unsuitable for upfront resection. In this analysis, the development of bevacizumab-induced hypertension was correlated with clinical outcomes.

Results:

Fifteen percent of patients developed ⩾grade 1 hypertension while receiving neoadjuvant chemotherapy, and 4% developed grade 3 hypertension. There was no correlation between the development of hypertension and radiological response rate (P=0.642), progression-free survival (P=0.644) or overall survival (P=0.480) in those who developed hypertension compared with those who did not.

Conclusion:

Bevacizumab-induced hypertension did not predict radiological response or survival in our study. The results highlight a number of important issues regarding the use of hypertension as a biomarker.

First-cycle rash and survival in patients with advanced non-small-cell lung cancer receiving cetuximab in combination with first-line chemotherapy: a subgroup analysis of data from the FLEX phase 3 study

BACKGROUND

The randomised phase 3 First-Line Erbitux in Lung Cancer (FLEX) study showed that the addition of cetuximab to cisplatin and vinorelbine significantly improved overall survival compared with chemotherapy alone in the first-line treatment of advanced non-small-cell lung cancer (NSCLC). The main cetuximab-related side-effect was acne-like rash. Here, we assessed the association of this acne-like rash with clinical benefit.

METHODS

We did a subgroup analysis of patients in the FLEX study, which enrolled patients with advanced NSCLC whose tumours expressed epidermal growth factor receptor. Our landmark analysis assessed if the development of acne-like rash in the first 21 days of treatment (first-cycle rash) was associated with clinical outcome, on the basis of patients in the intention-to-treat population alive on day 21. The FLEX study is registered with ClinicalTrials.gov, number NCT00148798.

FINDINGS

518 patients in the chemotherapy plus cetuximab group-290 of whom had first-cycle rash-and 540 patients in the chemotherapy alone group were alive on day 21. Patients in the chemotherapy plus cetuximab group with first-cycle rash had significantly prolonged overall survival compared with patients in the same treatment group without first-cycle rash (median 15·0 months [95% CI 12·8-16·4] vs 8·8 months [7·6-11·1]; hazard ratio [HR] 0·631 [0·515-0·774]; p<0·0001). Corresponding significant associations were also noted for progression-free survival (median 5·4 months [5·2-5·7] vs 4·3 months [4·1-5·3]; HR 0·741 [0·607-0·905]; p=0·0031) and response (rate 44·8% [39·0-50·8] vs 32·0% [26·0-38·5]; odds ratio 1·703 [1·186-2·448]; p=0·0039). Overall survival for patients without first-cycle rash was similar to that of patients that received chemotherapy alone (median 8·8 months [7·6-11·1] vs 10·3 months [9·6-11·3]; HR 1·085 [0·910-1·293]; p=0·36). The significant overall survival benefit for patients with first-cycle rash versus without was seen in all histology subgroups: adenocarcinoma (median 16·9 months, [14·1-20·6] vs 9·3 months [7·7-13·2]; HR 0·614 [0·453-0·832]; p=0·0015), squamous-cell carcinoma (median 13·2 months [10·6-16·0] vs 8·1 months [6·7-12·6]; HR 0·659 [0·472-0·921]; p=0·014), and carcinomas of other histology (median 12·6 months [9·2-16·4] vs 6·9 months [5·2-11·0]; HR 0·616 [0·392-0·966]; p=0·033).

INTERPRETATION

First-cycle rash was associated with a better outcome in patients with advanced NSCLC who received cisplatin and vinorelbine plus cetuximab as a first-line treatment. First-cycle rash might be a surrogate clinical marker that could be used to tailor cetuximab treatment for advanced NSCLC to those patients who would be most likely to derive a significant benefit.

A new approach for pharmacokinetics of single-dose cetuximab in rhesus monkeys by surface plasmon resonance biosensor

A novel assay method has been developed and validated, using surface plasmon resonance (SPR), for quantitation of cetuximab (C225) in monkey serum. By injecting non-labeled antibody samples onto a biosensor surface on which epidermal growth factor receptor (EGFR) was immobilized, the concentration of C225 can be accurately measured. This assay has a range of reliable response from 0.05 to 50 microg/ml C225 in monkey serum, which was well fitted with a sigmoidal model. The immobilized EGFR was found to be stable for at least 100 regeneration cycles at room temperature. Intra- and inter-assay CVs ranged from 3.20% to 8.89% and from 5.93% to 11.11%, accuracy from 92% to 107.52% and from 90% to 106.88%, respectively. Matrices such as 50% human serum, 50% Sprague Dawley rat serum, chimeric recombinant anti-CD20 monoclonal antibody, human gamma-globulin and chimeric recombinant her2 antibody did not interfere with C225 analysis on the sensor surface. This is the first report on the quantitation of C225 in monkey serum by an optical biosensor technology. This method was used to characterize the pharmacokinetics of C225 in rhesus monkeys. After a single-dose of intravenous infusion administration of 7.5, 24 and 75 microg/kg, average C(max) ranged from 168+/-28 to 1624+/-113 microg/ml, and AUC(0-infinity) ranged from 15,739+/-1059 to 295,017+/-44,533 microg h/ml. C225 elimination followed a bi-exponential profile with t(1/2) ranging from 2.7+/-0.7 to 6.7+/-0.1 h. It was non-linear serum pharmacokinetics of C225 across the investigated dosage range in monkeys (7.5-75 mg/kg).

Progress in the development of prognostic and predictive markers for gastrointestinal malignancies

Gastrointestinal cancers remain a significant cause of morbidity and mortality. While increasing therapeutic options have improved outcomes for many patients, they have also complicated treatment decision-making. Unfortunately, most patients with advanced gastrointestinal malignancies die from their disease. Prognostic and predictive markers could improve treatment significantly by identifying patients who may or may not require a given therapy, and determining those most likely to benefit from a therapy. Candidates for such markers include blood antigens and circulating tumor cells, tumor enzyme and gene expression, and pharmacodynamic endpoints. In this review, we summarize reported and ongoing research to define and validate prognostic and predictive markers in gastrointestinal malignancies, with an emphasis on colorectal cancer and brief overview of pancreatic and neuroendocrine tumors.

Prognostic versus predictive value of biomarkers in oncology

Numerous options are currently available for tumour typing. This has raised intense interest in the elucidation of prognostic and predictive markers. A prognostic biomarker provides information about the patients overall cancer outcome, regardless of therapy, whilst a predictive biomarker gives information about the effect of a therapeutic intervention. A predictive biomarker can be a target for therapy. Amongst the genes that have proven to be of relevance are well-known markers such as ER, PR and HER2/neu in breast cancer, BCR-ABL fusion protein in chronic myeloid leukaemia, c-KIT mutations in GIST tumours and EGFR1 mutations in NSCLC. Several reasons for the difficult elucidation of new markers will be addressed including the involvement of cellular pathways in tumour biology instead of single genes and interference in disease outcome as a result of anticancer therapies. Future perspectives for the development of prognostic and predictive markers will be given.

Molecular targets in squamous cell carcinoma of the head and neck

Worldwide more than a half million people develop Head and Neck cancer annually. Despite a significant decrease in smoking, about 40,000 new patients are diagnosed with carcinoma of the head and neck annually in the United States, and 11,000 of them succumb to their disease. More than 90% of these cancers are squamous cell carcinoma. The survival rates of patients with squamous cell carcinoma of the head and neck (SCCHN) have not improved significantly despite multimodality therapy including surgery, radiation therapy, and chemotherapy. Recently, molecular targeted agents have shown significant improvement in clinical outcomes in chronic myelogeneous leukemia with imatinib, breast cancer with trastuzumab, colon cancer with bevacizumab and cetuximab, and renal cell cancer with sorafenib and sunitinib. In SCCHN the epidermal growth factor receptor (EGFR) antibody cetuximab has shown promising results in a phase III trial in combination with radiation. How best to integrate these agents with the traditional treatment modalities of surgery, radiotherapy, and cytotoxic chemotherapy is of vital importance but has yet to be determined. This article will discuss the biology of molecular targeted agents as well as current clinical trials and future directions of these agents in SCCHN.

Current role of antibody therapy in patients with metastatic colorectal cancer

In less than 10 years, the number and importance of non-surgical treatment modalities in patients with colorectal cancer (CRC) have increased dramatically, both in the adjuvant and the advanced settings. However, despite the improvement of cytotoxic therapy in CRC, many patients still develop progressive disease and unfortunately in patients with disease resistant to 5-fluorouracil/folinic acid, irinotecan and oxaliplatin, no effective cytotoxic therapy is known. The rapidly expanding knowledge in tumor biology has encouraged optimism for the possibility to find and target tumor-specific mechanisms and thereby increase both efficacy and tolerance. A great number of 'targeted drugs' are being tested in clinical trials and some of these new drugs, like bevacizumab, cetuximab and panitumumab, are available for routine use in health care. These new targeted drugs will expand the therapeutic arsenal in CRC to a great extent, but they will also add to the complexity of treatment of CRC. In this review, we summarize the current status of antibody therapy in patients with CRC.