Not that many postings about Avastin are found on this board by using the 'Search' function. Here's some information provided by WebMd last year when it was first approved for breast cancer treatment:
Avastin for Breast Cancer Treatment
The cancer drug was recently approved to treat metastatic breast cancer, but there are still questions about Avastin that need to be answered.
By
Gina Shaw
WebMD Feature
Reviewed by
Matthew Hoffman, MD
In February 2008, the FDA approved a new drug, Avastin, for the treatment of
breast cancer that has metastasized.
Cancer that has metastasized has spread to other organs such as the lungs, liver, or bones. This decision to approve Avastin was somewhat surprising. In December, an FDA advisory committee had recommended that the FDA not approve the drug. The vote, though was close -- 5 to 4.
What is Avastin? And what can it do for some women with breast cancer?
Avastin is one of a newer group of
medications called anti-angiogenesis drugs or angiogenesis inhibitors. They work by choking off blood supply to tumors. This prevents the tumors from forming new blood vessels and cuts off their growth. Avastin had already been approved for use in
treating colorectal cancer and
lung cancer.
In women with metastatic breast cancer, a large clinical trial showed that Avastin both shrank existing tumors and lengthened what's called "progression-free survival." That's the time it takes for the disease to worsen. In the study, women who took Avastin in combination with the standard drug Taxol survived almost twice as long without their disease worsening as did women taking Taxol alone. That was an average of 11.3 months compared with 5.8 months. Tumors also shrank more in patients taking Avastin than in those taking Taxol alone. Another trial, released in June 2008, found similar results.
But there was no difference in what both oncologists and women with breast cancer see as most important: overall survival. Women taking Avastin did not live any longer than those only taking Taxol. That's why the FDA's decision in February was a bit of a surprise.
"As much as we try to be driven by science and evidence, if there's any possible advantage that can be given to the patient, we want to do it," says Yelena Novik, MD. Novik is medical director of the clinical trials office of the New York University Clinical Cancer Center at NYU Cancer Institute.
Avastin: Quality of Life vs. Quantity of Life
Avastin can be an important drug for many women with metastatic breast cancer, says Eric Weiner. Weiner directs the breast oncology center at the Gillette Center for Women's Cancers at the Dana-Farber Cancer Institute in Boston. "The fact of the matter is that progression-free survival can be important for patients," he says. "Living with cancer under control is obviously a good thing. That is it's good if you can do it without paying too much of a price in terms of side effects from the treatment."
Side effects are a concern with Avastin. They can include:
- High blood pressure
- Blood clots
- Heart problems
- Bowel perforation
- Proteinuria (excess protein in the urine, which can signal kidney damage)
"These are clear-cut issues which may also contribute to poor outcomes for some patients," says Novik. "We particularly have to be concerned about the risk of thromboembolic events -- a
stroke. This is rare, but it's a significant concern."
But Avastin's side-effect profile still compares favorably to many chemotherapy drugs. And for many women, the drug is well tolerated, says Lillie Shockney, RN. Shockney is administrative director of the Johns Hopkins Breast Center. "Women with metastatic disease are concerned about having quality of life and quantity of life at the same time. I'm working with a patient right now who's on Avastin. She's able to continue working, which is a real relief since she's a single woman and lives alone and needs to support herself for as long as she can. Some treatments can really beat you up, and you aren't able to be productive outside your home."
What the Future Holds for Avastin and Breast Cancer Treatment
With Avastin, there are no known predictors of a better or worse response to the drug. "If we could identify what sets apart the responders to Avastin, then those people who respond might, in fact, demonstrate a pretty clear survival advantage," says Weiner. "What we really need are better predictors of both toxicity and efficacy."
But such biomarkers for Avastin, unlike Herceptin, a drug that was approved in 2005 for the treatment of certain early-stage breast cancers, have not yet been identified. In the meantime, doctors at leading institutions like Dana-Farber, NYU, and Johns Hopkins are prescribing Avastin to many of their patients with metastatic breast cancer. When they do, it's usually in combination with Taxol -- the way it was in the clinical trials.
"Not every woman will receive Avastin," says Weiner. "For example, if I want to give a drug like capecitabine, which unlike Taxol does not involve
hair loss, then I would not give Avastin with it. That's because studies have not shown any advantages. But many women in our institution will receive chemotherapy plus Avastin."
A large trial is also now evaluating Avastin as a treatment for early-stage breast cancer. It has recruited some 1,800 of the nearly 5,000 patients it needs. The trial will compare Avastin to a placebo in combination with a current standard chemotherapy for early-stage breast cancer. The results are not expected for several years.
"We're still pondering how best to use Avastin," Novik says, "and we don't have all the answers."