Safety and efficacy of palliative systemic chemotherapy combined with colorectal self-expandable metallic stents in advanced colorectal cancer: A multicenter study.

PURPOSE: Self-expandable metallic stent (SEMS) placement is an accepted palliative therapy for management of acute malignant bowel obstruction in advanced colorectal cancer. Nevertheless, data are lacking on the effects of systemic chemotherapy combined with colorectal SEMS. The aim of this study was to investigate the safety and efficacy of palliative chemotherapy for advanced colorectal cancer combined with colorectal SEMS placement. PATIENTS AND METHODS: This multicentre retrospective study included all consecutive advanced colorectal cancer patients who received first-line palliative chemotherapy combined with endoscopic stenting for colorectal cancer with obstruction. We analyzed the number of cycles and the type of combination used. The primary endpoint was overall survival. Secondary endpoints included progression-free survival, response rate, grade 3-4 toxicity and the outcomes of SEMS for malignant colorectal obstruction. RESULTS: A total of 38 patients were included. Among them, 25 patients received oxaliplatin and 5-fluorouracil combination chemotherapy. Objective response and stabilization occurred in 38 and 24% of patients, respectively. The median overall survival and progression-free survival from the start of chemotherapy were 18 and 5months, respectively. The objective response rate and overall disease control rate were 38 and 62%, respectively. Toxicity was generally acceptable. Major complications related to stenting included perforation (8%), stent migration (5%), and reobstruction secondary to tumor ingrowths (13%). CONCLUSIONS: Chemotherapy combined with colonic stenting as a first-line treatment seems to be a valid option in advanced colorectal cancer patients with malignant colorectal obstruction.

An enzyme-linked immunosorbent assay to study bevacizumab pharmacokinetics.

INTRODUCTION: Bevacizumab is an antivascular endothelial growth factor humanized monoclonal antibody used to inhibit angiogenesis in cancer. It displays an important interindividual pharmacokinetic variability, which could explain part of the interindividual differences in clinical response. Therefore, an assay to measure bevacizumab serum concentrations is needed. METHODS: An enzyme-linked immunosorbent assay was developed using microtiter plates sensitised with vascular endothelial growth factor 165, a recombinant form of vascular endothelial growth factor. Lower and upper limits of quantitation as well as limit of detection were determined. Eight calibrators and three quality controls, with concentrations of 5 mg/L, 30 mg/L, and 75 mg/L, were tested on five occasions initially and on five subsequent occasions. Trough and peak serum concentrations of bevacizumab were measured in patients with metastatic colorectal cancer. Bevacizumab concentrations were described using a two-compartment population pharmacokinetic model with first-order constants. RESULTS: Imprecision and accuracy of calibrators and quality controls were 20% or less, except for the zero calibrator. The limit of detection was 0.033 mg/L. Lower and upper limits of quantitation were 5 and 75 mg/L, respectively. A total of 175 blood samples was available for analysis from 16 patients. Median (range) trough and peak concentrations during the treatment were 47.2 (9.6-106.9) mg/L and 159.3 (33.0-327.3) mg/L, respectively. CONCLUSION: This method is rapid, accurate, reproducible, and may be useful for pharmacokinetic and pharmacokinetic-pharmacodynamic studies as well as in therapeutic drug monitoring of bevacizumab.

[Tumour angiogenesis inhibition by therapeutic monoclonal antibodies]. / Anticorps monoclonaux thérapeutiques et ciblage vasculaire.

The development of therapeutic monoclonal antibodies (mAb) provided many great advances in the treatment of some diseases, in particular cancers. In the treatment of cancers, tumour angiogenesis inhibition by mAb occupies a major place. Tumour angiogenesis is a highly complex multifactor process in which many molecules, which originate both in the tumor cells or their environment, display pro- or anti-angiogenic functions. Many molecular pathways, among which those triggered by vascular endothelial growth factor, platelet-derived growth factor and integrins, are currently under investigation in therapeutic anti-angiogenesis research. Bevacizumab is to date the only mAb targeting the tumour vasculature that is currently used in clinical practice. Clinical trials have revealed its efficacy in colorectal, breast, kidney and lung cancers and gliobastoma multiforme. Such a success confirms the effectiveness in the treatment of cancer of using mAb inhibiting tumour angiogenesis, and many mAb targeting different angiogenesis pathways will probably be developed. Beyond clinical oncology, angiogenesis inhibition by mAb is of increasing interest in many other fields of medicine. It could offer interesting therapeutic strategies in some cardiovascular or rheumatologic diseases and currently represents the standard cure in some blinding ocular disorders.

An enzyme-linked immunosorbent assay for therapeutic drug monitoring of cetuximab.

Cetuximab is an anti-epidermal growth factor receptor monoclonal antibody used in the treatment of colorectal and head and neck cancers. Part of the interindividual differences in response may be explained by interindividual variability in pharmacokinetics. An assay measuring cetuximab serum concentrations is therefore needed. An enzyme-linked immunosorbent assay was developed using microtiter plates sensitized with a recombinant human epidermal growth factor receptor extracellular domain. Lower and upper limits of quantitation and limit of detection were determined. Eight standard calibrators (SCs) and 3 quality controls (QCs), that is, 0.75, 7.5, and 15 mg/L, were tested on 5 occasions on 1 day and on 5 occasions on different days. Trough and peak serum concentrations of cetuximab were measured in 15 patients with metastatic colorectal cancer and 1 patient with undetermined neoplasia undergoing cetuximab-based chemotherapy. Cetuximab concentrations were described using a 2-compartment population pharmacokinetic model. Imprecision and accuracy of SC and QC were < or = 20%, except for the 0 and 0.1 mg/L SC concentrations (< or = 20%). The limit of detection was 0.012 mg/L. Lower and upper limits of quantitation were 0.75 and 15 mg/L, respectively. A total number of 198 blood samples were available from the 16 patients. Median (range) trough and peak concentrations during the treatment were 49.6 (5.8-105.4) and 177.2 (97.5-235) mg/L, respectively. This method is rapid, accurate, and reproducible and may be useful for pharmacokinetic and pharmacokinetic-pharmacodynamic studies, as well as in therapeutic drug monitoring of cetuximab.

[Target antigens for therapeutic antibodies in oncology: many candidates, few successes]. / Antigènes-cibles d'anticorps thérapeutiques en cancérologie: beaucoup de candidats, peu d'élus.

Targeted therapies, especially monoclonal antibodies, have reached an increasing importance in oncology. High-throughput techniques have allowed the identification of numerous transcripts, proteins, or non-protein antigens, which have generated the concept of immunome. This epitope library constitutes a huge reservoir of candidate antigens susceptible to become some say the target of an antibody for passive immunotherapy. However, the conception and development of a therapeutic antibody represent a very important investment, both in terms of human power and finance, such that there is a requirement for an early identification of the best candidates among the potential target antigens. Among multiple criteria, the function of the antigen is crucial when it has been identified. A receptor antigen can be targeted by an agonistic or an antagonistic antibody, according to what is sought. When the antigen function is unknown, a therapeutic antibody can be useful, for instance through induction of apoptosis or through accrual of immuno-competent cells, via its Fc portion (complement-dependent cytotoxicity or antibody-dependent cytotoxicity). Other antibody features, unrelated to its function, can also be exploited, such as its internalisation or its translocation in membrane lipid rafts. The expression of the target antigen may also be crucial, in terms of localisation and levels, as is its tumour specificity, which can influence the efficacy and toxicity of the targeting antibody. The multiplicity of the factors to be taken into account and the complexity of the mechanism of action of therapeutic antibodies renders the choice of a target antigen a hazardous bet. Very often, this is only when the clinical efficacy of a targeting antibody is demonstrated that the antigen can be considered as a good target.