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As researchers have learned more about the molecular and
genetic changes in cells that cause cancer, they have been able to
develop newer drugs that specifically target some of these changes.
These targeted drugs work differently from standard chemotherapy drugs
and have different side effects. Targeted drugs are proving to be
especially important in diseases such as kidney cancer, where
chemotherapy has not been shown to be very effective. The term targeted
therapy may not be the most accurate way to describe these newer drugs,
as even traditional chemotherapy targets certain cellular functions.
However, this is the term commonly used for newer agents that have a
more focused mechanism of action
Several targeted drugs have been approved by the FDA for use
against advanced kidney cancer. These include drugs that stop
angiogenesis (growth of the new blood vessels that nourish cancers) and
drugs that target other important cell growth factors. These drugs are
often used as the first line of treatment against advanced kidney
cancers. While they may shrink or slow the growth of the cancer, it's
not yet clear if any of these drugs can be curative.
Sorafenib (Nexavar)
This drug has been shown to slow the progression of the cancer
in some patients with advanced disease. It acts by blocking both
angiogenesis and growth-stimulating molecules in the cancer cell.
Sorafenib does this by blocking several important cellular enzymes
called tyrosine kinases that are important for cell growth and
survival. It is taken as a pill. The most common side effects seen with
this drug include fatigue, rash, diarrhea, increases in blood pressure,
and redness, pain, swelling, or blisters on the palms of the hands or
soles of the feet (hand-foot syndrome).
Sunitinib (Sutent)
Sunitinib also blocks several tyrosine kinases, but not the
same ones as sorafenib. This drug is a pill that has been shown to
shrink or slow the progression of kidney cancer in many cases. It
attacks both blood vessel growth and other targets that stimulate
cancer cell growth. The most common side effects are nausea, diarrhea,
changes in skin or hair color, mouth sores, weakness, and low white and
red blood cell counts. Other possible effects include tiredness, high
blood pressure, congestive heart failure,, bleeding, hand-foot
syndrome, and low thyroid hormone levels.
Temsirolimus (Torisel)
Temsirolimus is given as an intravenous (IV) infusion. It
works by blocking a cell protein known as mTOR, which normally promotes
cell growth and division. This drug has been shown to be helpful
against advanced kidney cancers that have a poorer prognosis because of
certain factors. The most common side effects of this drug include skin
rash, weakness, mouth sores, nausea, loss of appetite, fluid buildup in
the face or legs, and increases in blood sugar and cholesterol levels.
Rarely, more serious side effects have been reported.
Everolimus (Afinitor)
This drug also blocks the mTOR protein. It is taken as a pill once a day.
Everolimus is used to treat advanced kidney cancers after other drugs such
as sorafenib or sunitinib have been tried. Common side effects of this drug
include mouth sores, increased risk of infections, nausea, loss of appetite,
diarrhea, skin rash, feeling tired or weak, fluid buildup (usually in the legs),
and increases in blood sugar and cholesterol levels. A less common but
serious side effect is damage to the lungs, which can cause shortness of
breath or other problems.
Bevacizumab (Avastin)
This is an IV drug that works by slowing the growth of new
blood vessels. Recent studies have shown it may be helpful against
kidney cancer especially when used along with interferon-alpha. Bevacizumab is usually tolerated well by
patients, but it can cause serious side effects such as increases in
blood pressure, bleeding or blood clotting problems, and wound healing
problems.
Doctors are still learning the best ways to use these targeted
drugs against advanced kidney cancers. As of now, they are most often
used one at a time. If one doesn't work, another may be tried. It's not
yet known if any one of these drugs is clearly better than the others,
if combining them might be more helpful than giving them one at a time,
or if one sequence is better than the other. Studies are under way to
help answer these questions. Last Medical Review: 02/18/2009 Last Revised: 05/14/2009
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