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It's an ambitious and ingenious idea, one that
has great potential to help men with prostate cancer get new drugs
much faster — and it could save millions of dollars, as well. There
are an estimated 10,000 drugs already known to medicine and approved
for use in patients. Many of them turn out to be helpful for more
than one ailment. And yet, there's no centralized reservoir of knowledge
about these drugs, says molecular scientist Jun Liu, Ph.D., the
Peter Jay Sharp Foundation Scholar.
He is working to change this, and he's got many
good reasons — at least 800 million of them. That's how many dollars
it takes for just one new drug to be developed and brought, after
many tests and clinical trials, to the patients who need it. Even
with a host of scientific advances that have speeded up this process,
"the average time from discovery to approval has more than doubled
since 1964, from 6.5 to 14.8 years," Liu says. Even more sobering,
he adds, less than one-quarter of the drugs that advance to Phase
I clinical trials ever make it to the market. "Despite an almost
thirty-fold increase to $33 billion in research and development
from 1977 to 2003, the number of new drugs approved by the FDA remains
relatively flat at 15 to 30 each year."
It takes, on average,
nearly 15
years for a newly discovered drug
to make it to the people who need
it most. But there are thousands
of already-existing, alreadyapproved
drugs out there, waiting
to be tapped for new needs.
In contrast, the treasury of thousands of already-existing,
already-approved drugs has been barely tapped. More than three years
ago, Liu and his former graduate student, Curtis Chong, began an
effort to systematically collect and screen all available FDAapproved
drugs. So far, they have amassed a library that contains about 1,900
FDAapproved drugs and more than 600 that either entered Phase II
clinical trials (were shown to be safe and to have few side effects)
or were approved abroad for clinical use. From this research, "we
have identified several drugs that possess potent and unexpected
anti-angiogenic properties," Liu says. "Two of these, an immunosuppressive
drug called mycophenolic acid, and an antifungal drug named itraconazole,
have been shown to work in animal models of angiogenesis, or tumor
growth."
With support from the Patrick C. Walsh Prostate
Cancer Research Fund, he and colleagues continue to expand their
library, and to examine the promising drugs they turn up. They are
screening the library against prostate cancer cell lines, looking
for novel drugs that inhibit the spread of cancer, or that seem
to be more effective when combined with other drugs. "When we identify
new inhibitors, we try to validate their mechanisms of action and
see how well they work in different prostate tumor models in animals,"
Liu explains. "We are also carrying out follow-up studies on some
of the most promising newly identified angiogenesis inhibitors,
to facilitate their potential use in people with prostate cancer
and other types of cancer."
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