Development of Rationally Designed, Target-Based Agents for the Treatment of Advanced Colorectal Cancer

Microfabricated analytical systems for integrated cancer cytomics

Tracking and understanding cell-to-cell variability is fundamental for systems biology, cytomics and computational modelling that aids e.g. anti-cancer drug discovery. Limitations of conventional cell-based techniques, such as flow cytometry and single cell imaging, however, make the high-throughput dynamic analysis on cellular and subcellular processes tedious and exceedingly expensive. The development of microfluidic lab-on-a-chip technologies is one of the most innovative and cost-effective approaches towards integrated cytomics. Lab-on-a-chip devices promise greatly reduced costs, increased sensitivity and ultrahigh throughput by implementing parallel sample processing. The application of laminar fluid flow under low Reynolds numbers provides an attractive analytical avenue for the rapid delivery and exchange of reagents with exceptional accuracy. Under these conditions, the fluid flow has no inertia, enabling the precise dosing of drugs, both spatially and temporally. In addition, by confining the dimensions of the microfluidic structure, it is possible to facilitate the precise sequential delivery of drugs and/or functional probes into the cellular systems. As only low cell numbers and operational reagent volumes are required, high-throughput integrated cytomics on a single cell level finally appears within the reach of clinical diagnostics and drug screening routines. Lab-on-a-chip microfluidic technologies therefore provide new opportunities for the development of content-rich personalized clinical diagnostics and cost-effective drug discovery. It is largely anticipated that advances in microfluidic technologies should aid in tailoring of investigational therapies and support the current computational efforts in systems biology.

Microfluidic cell arrays in tumor analysis: new prospects for integrated cytomics

The recent introduction of molecularly targeted anticancer therapeutics has revealed a great need for a new class of clinical bioassays. The shift from cytotoxic chemotherapy to biomolecular therapeutics requires that efficacy is assessed at the biologically active dose that modulates the target, rather than using the conventional dose-toxicity relationship. In this context, functional cytomics is slowly becoming an omnipotent part of the post-genomic drug-discovery pipelines. Although, it is widely recognized in the drug-discovery arena that the validation of therapeutic targets revealed by proteomic and genetic screens requires functional cell-based assays, their widespread clinical applications are still underdeveloped. In this context, microfluidic cell array technologies provide important technological advances that allow for fundamentally new capabilities in the spatiotemporal control of molecules and cells. Pioneering lab-on-a-chip devices, such as microfluidic cell arrays, allow for a lucid integration of multiparameter data, obtained from functional cell-based assays, as well as from proteomic and genetic screening. They also offer opportunities for fabrication of parallelized and fully addressable perfusion microarrays aiming at greatly reduced equipment costs, simplified operation, increased sensitivity and throughput by implementing, for example, a parallel processing principle. Lab-on-a-chip microfluidic cell arrays therefore provide new opportunities for the development of content-rich personalized clinical diagnostics and higher-throughput clinical screening in oncology.

Mitomycin C and Etoposide in Advanced Colorectal Carcinoma

BACKGROUND

Aim of this study was to evaluate the activity of a combination regimen of chemotherapy containing mitomycin C (MMC) and etoposide (ETO) in advanced colorectal carcinoma.

METHODS

Fourteen pretreated patients received MMC 2 mg/m2 and ETO 60 mg/m2, days 1-5 every 28 days. The clinical study was interrupted since no clinical response was observed in 14 patients following four courses of chemotherapy. An in vitro study was then performed on HTC-8 cell line. The cytotoxic activity of the MMC/ETO combination was tested by sulforhodamine B assay and the type of drug interaction was assessed using the method of Chou and Talalay. Cell cycle perturbations and apoptosis were evaluated by flow cytometry.

RESULTS

While MMC and ETO were singularly active, the simultaneous exposure of cells to both drugs and the sequence MMC-->ETO ensued in antagonistic interaction at all levels of killed cell fraction. Conversely, the sequence ETO-->MMC produced a synergistic interaction.

CONCLUSIONS

These results suggest that the activity of the MMC/ETO combination is highly schedule-dependent and that the experimental drug associations should be based on a preclinical rationale before clinical trials are designed.

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.