How Avastin is Believed to Work: Starving the Tumor
Understanding how your treatment can work for you is a big part of what you
can do to fight back.
In order to survive, grow, or spread, tumors need a continuous supply of
oxygen and nutrients, which they get by creating their own network of blood
vessels. This process is called angiogenesis (an'-gee-o-jen'-i-sis).
Avastin is thought to work by blocking a protein released by both normal
cells and cancer cells that helps cause angiogenesis. This protein is called
VEGF and is produced throughout the life of the tumor. By controlling the growth
of blood vessels, Avastin can starve your cancer of the nutrients and
oxygen it needs to grow and spread. This is why Avastin is a
What are the most common side effects of Avastin?
Common side effects that occurred in more than 10% of people who received
Avastin for different cancer types, and at least twice the rate of the
comparison group, were nosebleeds, headache, high blood pressure, inflammation
of the nose, too much protein in the urine, taste change, dry skin, rectal
bleeding, tear production disorder, back pain, and inflammation of the skin
(exfoliative dermatitis). Across all trials, treatment with Avastin was
permanently stopped in 8.4% to 21% of people because of side effects.
Tumor growth without Avastin
Tumors get what they need to grow and spread from blood vessels.
- A tumor continuously sends out a protein called VEGF to nearby blood
vessels. This protein causes new blood vessels to grow toward the tumor, a
process called angiogenesis
- Once these new vessels reach the tumor, they provide the supply of
blood that brings oxygen and other nutrients to the
Starving the tumor with Avastin
With Avastin, tumors can't get the nutrients they need to grow.
- Avastin may prevent blood vessels from forming by blocking VEGF, a
protein that is produced by normal cells and overproduced by cancer cells. In
this way, Avastin starves the tumor of what it needs to grow and
- Because it helps prevent blood vessels from forming (angiogenesis),
Avastin is a tumor-starving therapy (anti-angiogenic
Effective for Recurrent Ovarian Cancer
Data from two Phase II studies suggest that Avastin® (bevacizumab) is
effective and reasonably well tolerated for the treatment of recurrent ovarian
cancer. The details of these studies appeared in the November 20, 2007 issue of
the Journal of Clinical Oncology.
Avastin is a recombinant humanized monoclonal antibody to vascular
endothelial growth factor (VEGF). VEGF appears to play an important role in
tumor angiogenesis, and blocking this activity should have an anti-tumor effect.
Clinical trials of Avastin have shown activity in a variety of tumors,
especially when combined with other agents. However, there have been only three
reports of treatment of ovarian cancer with Avastin alone or in combination and
these reports involved only a small number of patients (see related news).
A Phase II trial carried out by the Gynecologic Oncology study Group
evaluated Avastin in 62 patients with recurrent or refractory ovarian cancer.
Two-thirds of patients had received two prior
treatment regimens. Forty-two percent of patients were classified as
platinum-resistant. All patients were treated with Avastin as a single agent for
- 21% of patients experienced a complete or partial response.
- The median duration of response was 10 months.
- 40% of patients survived at least six months without progression.
- Median progression-free survival was 4.7 months.
- Median overall survival was 17 months.
Prior responses to chemotherapy, age of the patient, number of prior
chemotherapy regimens, or their ability to perform tasks of daily living were
not associated with outcomes with treatment with Avastin in terms of cancer
progression or death.
The second study involved 44 patients with ovarian cancer who had received
one to three prior treatment regimens.
Eighty-four percent of these
patients were deemed to be platinum-resistant.
- Partial responses were observed in 16%.
- Median progression-free survival was 4.4 months
- Median survival was 10.7 months.
These researchers concluded that Avastin appears to provide anticancer
activity and is generally well tolerated for patients with ovarian cancer who
have received prior therapy including those who were platinum-resistant. Side
effects included hypertension, GI perforation, bleeding and wound healing
Comments: The data from these two studies
add significantly to the information available about response rates to Avastin
in women with recurrent ovarian cancer.