Trastuzumab as the lead monoclonal antibody in advanced breast cancer: choosing which patient and when

Improving cancer treatment by addressing legislative and regulatory issues

OBJECTIVES

To explore legislative and legal barriers to improving cancer treatment.

METHODS

The advocacy agenda of Cancer Council Australia was examined for key issues, and examples drawn from Australian law were presented at a conference entitled 'Legislate, regulate and litigate: legal perspectives on cancer prevention and treatment' at the University of Sydney.

RESULTS

The introduction of electronic medical records and linkage of data sets from registries can produce very useful public health information, but could be a threat to individual privacy. The balance between these must underpin legislation and regulation. The new drug approval process must keep pace with developments such as targeted therapies, where tests to identify the presence of the target must also be approved simultaneously. The regulation of complementary and alternative medicines in cancer is challenging given their widespread use. In cancer research, it is vital that the important ethics and governance review process does not become a barrier to the ability to complete research in a reasonable time frame. A specific issue for future treatments and diagnostic tests that are to be targeted at genes and their products is to clarify gene patenting laws so that invention is rewarded, not mere discovery. The nature of the workforce will need to change to meet the treatment needs of an increasing incidence of cancer in an aging population, but regulation will need to ensure the maintenance of safety and quality standards.

CONCLUSION

The flexibility of legislation and regulation to meet a rapidly changing environment is key to ensuring the timely adoption of new cancer treatments to improve cancer outcomes.

erbB2 Overexpression in Uterine Serous Cancer: A Molecular Target for Trastuzumab Therapy

Endometrial cancer is the most common female genital tract malignancy in the United States. Type I endometrial cancer is usually diagnosed at an early stage, and has a good prognosis. Type II is very aggressive, and is responsible for most uterine cancer relapses and deaths. Uterine serous adenocarcinomas (USC) constitute the majority of Type II variants. They have a higher propensity for lymph node and distant metastases. They are frequently aneuploid and associated with p53 mutations. erbB2 overexpression in USC has been described. The incidence, which is higher in African Americans, ranges from 18-80%. erbB2 overexpression was found to be associated with higher stage, chemoresistance, and worse survival. Trastuzumab a humanized mAb was approved by the FDA for treatment of breast cancers that overexpress erbB2 in combination with standard chemotherapy. Evidence of trastuzumab activity in USC has been reported in vitro, as well as in case reports of advanced and recurrent cases. Promising results were obtained in these heavily pretreated patients either with trastuzumab alone or in combination with chemotherapy. This supports the hypothesis that trastuzumab may very well be an attractive and viable treatment option for advanced stage USC tumors that overexpress the erbB2, and is worthy of further study.

The HER-2 receptor and breast cancer: ten years of targeted anti-HER-2 therapy and personalized medicine

The human epidermal growth factor receptor (HER-2) oncogene encodes a transmembrane tyrosine kinase receptor that has evolved as a major classifier of invasive breast cancer and target of therapy for the disease. The validation of the general prognostic significance of HER-2 gene amplification and protein overexpression in the absence of anti-HER-2 targeted therapy is discussed in a study of 107 published studies involving 39,730 patients, which produced an overall HER-2-positive rate of 22.2% and a mean relative risk for overall survival (OS) of 2.74. The issue of HER-2 status in primary versus metastatic breast cancer is considered along with a section on the features of metastatic HER-2-positive disease. The major marketed slide-based HER-2 testing approaches, immunohistochemistry, fluorescence in situ hybridization, and chromogenic in situ hybridization, are presented and contrasted in detail against the background of the published American Society of Clinical Oncology-College of American Pathologists guidelines for HER-2 testing. Testing issues, such as the impact of chromosome 17 polysomy and local versus central HER-2 testing, are also discussed. Emerging novel HER-2 testing techniques, including mRNA-based testing by real-time polymerase chain reaction and DNA microarray methods, HER-2 receptor dimerization, phosphorylated HER-2 receptors, and HER-2 status in circulating tumor cells, are also considered. A series of biomarkers potentially associated with resistance to trastuzumab is discussed with emphasis on the phosphatase and tensin homologue deleted on chromosome ten/Akt and insulin-like growth factor receptor pathways. The efficacy results for the more recently approved small molecule HER-1/HER-2 kinase inhibitor lapatinib are also presented along with a more limited review of markers of resistance for this agent. Additional topics in this section include combinations of both anti-HER-2 targeted therapies together as well as with novel agents including bevacizumab, everolimus, and tenespimycin. A series of novel HER-2-targeting agents is also presented, including pertuzumab, ertumaxomab, HER-2 vaccines, and recently discovered tyrosine kinase inhibitors. Biomarkers predictive of HER-2 targeted therapy toxicity are included, and the review concludes with a consideration of HER-2 status in the prediction of response to non-HER-2 targeted treatments including hormonal therapy, anthracyclines, and taxanes.

Toward theragnostics

Theragnostics is a treatment strategy that combines therapeutics with diagnostics. It associates both a diagnostic test that identifies patients most likely to be helped or harmed by a new medication, and targeted drug therapy based on the test results. Bioinformatics, genomics, proteomics, and functional genomics are molecular biology tools essential for the progress of molecular theragnostics. These tools generate the genetic and protein information required for the development of diagnostic assays. Theragnostics includes a wide range of subjects, including personalized medicine, pharmacogenomics, and molecular imaging to develop efficient new targeted therapies with adequate benefit/risk to patients and a better molecular understanding of how to optimize drug selection. Furthermore, theragnostics aims to monitor the response to the treatment, to increase drug efficacy and safety. In addition, theragnostics could eliminate the unnecessary treatment of patients for whom therapy is not appropriate, resulting in significant drug cost savings for the healthcare system. However, the introduction of theragnostic tests into routine health care requires both a demonstration of cost-effectiveness and the availability of appropriate accessible testing systems. This review reports validation studies in oncology and infectious diseases that have demonstrated the benefits of such approach in well-defined subpopulations of patients, moving the field from the drug development process toward clinical practice and routine application. Theragnostics may change the usual business model of pharmaceutical companies from the classic blockbuster model toward targeted therapies.