Traditional treatment of mesothelioma and other cancers has focused on
resecting the tumor, radiating it or poisoning it. A relatively new approach,
however, uses a seemingly obvious, but difficult method to attack the
tumor starving it.
For a tumor to grow, it must develop its own internal network of blood
vessels, peripheral to the blood vessels of the host body while still
tapping into them. This new notion of starving the tumor hinges on preventing
the tumor from developing new blood vessels by stopping vascular endothelial
growth factor (VEGF), the process of spurring new blood vessel formation,
thereby halting tumor growth and even potentially shrinking the tumor.
Drugs that can accomplish this are called angiogenesis inhibitors or characterized
Currently, there is one angiogenesis inhibitors available for treating
SU5416, also known as semaxinib, is manufactured by pharmaceutical company
Pharmacia's Sugen division. The drug is in a clinical trial for mesothelioma
patients at the University of Chicago. Run by Dr. Hedy Kindler of the
University of Chicago's Pritzker School of Medicine, the project is
funded in part by the Mesothelioma Applied Research Foundation (
MARF) a 501(c)(3) not-for-profit organization whose mission is to eradicate
mesothelioma as a life-ending disease.
Other similar products are also in the pipeline. One such product is ZD
1839, more popularly known as
. The product differs from angiogenesis inhibitors in that, instead of
stopping vascular endothelial growth factor, it is a signal transduction
inhibitor. The process of stopping the tumor is related to anti-VEGF drugs,
but the method is different. The cancer cells have epidermal growth factor
receptors (EGFRs). The receptors receive epidermal growth factors, and
tyrosine kinase is released, causing the cancer cell to grow. Iressa attaches
to the receptor instead and prevents the release of the tyrosine kinase,
thereby stopping the cell growth.
It has gone through clinical trials with the Cancer and Leukemia Group
B in Nevada, and more details about the trial may be found at the organization's
website at http//www.calgb.org. Iressa is manufactured by pharmaceutical
company AstraZeneca, which also has three other angiogenesis inhibitors
in the pipeline. As of July 26, 2001, those three products were all expected
to be in clinical trials by 2003 at the latest. As of January 3, 2002,
AstraZeneca had submitted clinical data to the FDA seeking approval for
the drug. It was granted fast track review and is expected to be on the
market for treatment in mid-2002.
Other pharmaceutical companies are also producing angiogenesis inhibitors;
however, they have yet to test these products for effectiveness against
Genentech has developed Avastin (or bevacizumab); however, it is currently
being tested primarily for breast and colorectal cancer as well as --
occasionally -- prostate cancer.
ImClone Systems, Inc. was developing an angiogenesis inhibitor called IMCC225,
or cetuximab; they sold the licensing and research to BristolMyers Squibb,
who renamed the drug erbitux and went on to send it to clinical trials.
Presently, there are no trials of the drug open to mesothelioma patients.
Pfizer had developed a product called prinomastat; all clinical trials
for the drug (none of which included mesothelioma) were halted in January
2001, due to disappointing responses in patients.