|
__________________
A Proud webmaster to the internet's most informed, educated, COMPASSIONATE and caring group of breast cancer survivors. Illegitimi non carborundum My Album |
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
05-31-2008, 04:57 PM | #2 |
Senior Member
Join Date: Aug 2006
Location: Pennsylvania
Posts: 1,080
|
Avastin for Breast Cancer
Avastin works by choking off the blood vessels that provide a tumor with oxygen and nutrients (angiogenesis). Angiogenesis is essential for the growth and metastasis of cancer. With Avastin, the target is not the cells themselves but rather VEGF secreted by the tumor cells.
At a critical point in the growth of a tumor, the tumor sends out signals to nearby endothelial cells to activate new blood vessel growth. One of the endothelial growth factors (VEGF) is expressed by many tumors (but not all) and seems to be important in sustaining tumor growth. Avastin complexes with free VEGF and blocks its action. And when you use Avastin as an anti-angiogenic enhancer and potentiator, the abrogating effect of it upon VEGF reduces the secretion of VEGF by the tumor cells. It both reduces VEGF and makes Avastin work better, possibly overcoming tumor resistance to Avastin. The idea that approving drugs based on population studies has its limits. What may or my not work for the average population may not apply to the individual. There is a "functional" bio-marker (AngioRx™ Angiogenesis Profile) for Avastin and other anti-angiogenesis-related drugs. The assay can report prospectively to a physician specifically which agent would benefit a cancer patient by thesting that patient's "live" cancer cells. Drug sensitivity profiles differ significantly among cancer patients even when diagnosed with the same cancer. Knowing the drug sensitivity profile of a specific cancer patient allows the treating oncologist to prescribe a therapy that will be the most effective against the tumor cells "before" placing potentially toxic agents into the patient. |
06-28-2008, 10:38 AM | #3 |
Senior Member
Join Date: Aug 2006
Location: Pennsylvania
Posts: 1,080
|
Avastin and Tykerb First Clinically-Exploitable Antivascular Drug Combination
Direct anti-tumor and anti-vascular effects were studied of Tykerb, Nexavar and Avastin in fresh biopsy specimens of breast cancer. While the other clinically-available 'nib' drugs have been shown to have anti-vascular activity, anti-vascular activity of Tykerb has not been previously reported.
Angiogenesis studies are limited by the clinical relevance of laboratory model systems. They don't do "real world" studies under "real world" conditions. Patient outcomes need to be reported in real-time, so patients and cancer physicians can learn immediately if and how patients are benefiting from new drug therapies. Cell culture detection of microvascular cell death in clinical specimens of human neoplasms and peripheral blood can identify the activity of both single drugs and combinations of drugs at the level of individual patients with individual cancers. It works by measuring drug effects (real-time) upon endothelial cells which make up blood vessels. Drugs like Avastin had striking anti-microvascular effects but minimal anti-tumor effects. Tarceva and Gleevec had mixed antitumor and anti-microvascular effects. Anti-microvascular effects of Tarceva and Iressa were equal to those of Sutent and Nexavar. Anti-microvascular additivity was observed between Avastin and other drugs on an individual basis. Conclusions of the study had shown that Tykerb has antivascular activity superior to that of Nexavar. Avastin + Tykerb may be the first clinically-exploitable antivascular drug combination. High dose, intermittent 'bolus' schedules of Tykerb to coincide with Avastin administration may be clinically advantageous, even in HER2-negative tumors. The system utilized for the study was a functional profiling assay, which may be used to individualize antivascular therapy. It can be adapted for simple, inexpensive and sensitive/specific detection of tissue and circulating microvascular cells in a variety of neoplastic and non-neoplastic conditions, for drug development, and individualized cancer treatment. The cell-based assay can accurately sort drugs into categories of above average probability of providing clinical benefit on one hand and below average probability of providing clinical benefit on the other hand, based both on tumor response and patient survival. |
|
|