Great news for those who are interested in personalized medicine. One of the first examples of this special field of medicine was the potential use of Herceptin in breast cancer. Now the U.S. Food and Drug Administration approved a genetic test for determining whether patients can be treated with the drug Herceptin (trastuzumab).
The SPOT-Light HER2 CISH kit is a test that measures the number of copies of the HER2 gene in tumor tissue.
A healthy breast cell has two copies of the HER2 gene, which sends a signal to cells, telling them when to grow, divide and make repairs. Patients with breast cancer may have more copies of this HER2 gene, prompting them to overproduce HER2 protein so that more signals are sent to breast cells. As a result, the cells grow and divide much too quickly.
The SPOT-Light test counts the number of HER2 genes in a small sample of removed tumor. The removed piece is stained with a chemical that causes any HER2 genes in the sample to change color.
Patients who over-produce HER2 protein are typically treated with the drug Herceptin, which targets HER2 protein production. This helps to stop the growth of HER2 cancer cells.
Of course, patients with normal HER2 genes are not the best candidates for Herceptin therapy. So this test is not only useful for the patients but makes the whole process cost-effective as well (a full course of treatment costs about 70 000 US dollars).
That is personalized medicine…
More about personalized medicine:
Future Medicine is the only journal dedicated totally to personalized medicine. I share the table of contents and some interesting excerpts from the latest issue with you (some of the articles are free to access, some are not):
If pharmacogenomics is to reach primary-care clinical practice, the genetic knowledge, skills and attitudes of professionals have to be improved at both undergraduate and postgraduate level. A recent report has stressed the need for genetic education to infiltrate all aspects of healthcare, from undergraduate to continuing professional development for all healthcare practitioners.
The lack of adequate counseling and consequent misunderstanding of test results could lead to confusion and apprehension regarding results. Genetic results for common complex disorders are complicated by the fact that they are probabilistic in nature, and must be interpreted in the context of family history, present health status and other environmental conditions. Consumers who obtain a test revealing a form of increased risk may overestimate the risk they have of developing disease and this may cause undue stress and anxiety and unnecessary follow-up tests or treatments.
If we have evidence-based web 2.0, we need evidence-based pharmacogenomics as well. That is why I try to create a database of real clinical implications. The final report on pharmacogenomics released by US Advisory Committee is a must-read for medical professionals. Some excerpts:
PGx has drawn great attention for its potential to redirect personal care and public health paradigms in the United States and abroad. It has begun to offer powerful tools for using information about individual genetic variations and drug responses to “personalize” or “customize” health care decisions. Some early applications of PGx include HER2/neu testing of metastatic breast cancer patients to determine responsiveness to Herceptin®, the use of thiopurine 6-mercaptopurine testing to manage the treatment of children with acute lymphoblastic leukemia, and the use of CYP2C9 and VKORC1 testing of those at risk for harmful blood clots to guide warfarin dosage.
PGx has the potential to improve management of chronic diseases, which pose the greatest clinical and economic burdens in the United States and elsewhere. The current therapeutic approach for these diseases is to slow their progression and diminish their symptoms. PGx may help improve symptoms and reduce health care costs through more effective treatments and fewer avoidable ADRs. However, PGx also could increase costs if drugs for smaller markets are priced higher to recoup research and development costs or if PGx testing is added to the cost of drug treatment.