gdpawel
Senior User
Joined: 15 Jan 2005
Posts: 125
Location: Pennsylvania
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 Posted: Fri Jun 24, 2005 9:07 am Post subject: Is There Success With Both Iressa and Tarceva? |
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Targeted treatments like Iressa and Tarceva, take advantage of the biologic differences between cancer cells and healthy cells by "targeting" faulty genes or proteins that contribute to the growth and development of cancer. Many times these drugs are combined with chemotherapy, biologic therapy (immunotherapy), or other targeted treatments.
Clinicians have learned that the same enzymes and pathways are involved in many types of cancer. However, understanding targeted treatments begins with understanding the cancer "cell." In order for cells to grow, divide, or die, they send and receive chemical messages. These messages are transmitted along specific pathways that involve various genes and proteins in the cell.
Cancer cells often have many mutations in many different pathways, so even if one route is shut down by a targeted treatment, the cancer cell may be able to use other routes.
Targeted therapies are typically not very effective when used singularly or even in combination with conventional chemotherapies. The targets of many of these drugs are so narrow that cancer cells are likely to eventually find ways to bypass them.
Physicians may have to combine several targeted treatments to try an achieve cures or durable responses for more complicated tumors like those that occur in the breast, colon and lung.
These targeted therapies produce limited results because they can help a relatively small subgroup of cancer patients. But when they work, they produce very good responses. With targeted therapy, the trick is figuring out which patients will respond. Tests to pinpoint those patients cannot be accomplished with genetic testing.
All the gene amplification studies, via genetic testing, tell us is whether or not the cancer cells are potentially susceptible to a mechanism/pathway of attack. They don't tell you if one drug (Iressa) is better or worse than another drug (Tarceva) which may target a certain mechanism/pathway. Cell-based functional analysis can accomplish this, or the physician can "trial-and-error" what will work. That's up to the patient.
The cell is a system, an integrated, interacting network of genes, proteins and other cellular constituents that produce functions. You need to analyze the systems’ response to drug treatments, not just one target or pathway, or even a few targets/pathways.
Literature Citation:
Functional profiling with cell culture-based assays for kinase and anti-angiogenic agents Eur J Clin Invest 37 (suppl. 1):60, 2007
Functional Profiling of Human Tumors in Primary Culture: A Platform for Drug Discovery and Therapy Selection (AACR: Apr 2008-AB-1546) |
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