After a nearly four year review process, the FDA decided to remove Avastin’s approval for the treatment of metastatic breast cancer.
Avastin’s approval ordeal has been a difficult and controversial issue for breast cancer patients, some of whom feel that the powerful anti-angiogenic drug has contributed to the success of their treatment.
However, breast cancer patients might not be the only cancer patients that have concerns regarding the Avastin decision. Avastin is an approved drug for metastatic colorectal cancer (MCRC) and is part of the standard of care for many colorectal cancer patients, typically given in combination with chemotherapy drugs like FOLFOX or FOLFIRI for first- or second-line treatment regimens. The announcement by the FDA regarding Avastin may have colorectal cancer patients experiencing confusion and anxiety as to why the FDA continues to approve the use of Avastin in treating metastatic colorectal cancer (MCRC).
Avastin continues to be approved for treatment of MCRC because results from several large studies conducted over long periods of time repeatedly have shown that Avastin therapy delays the growth and spread of cancer and prolongs survival. These are benefits that far outweigh the risks associated with the drug, which include high blood pressure, hemorrhaging, and blood clots.
Avastin first received FDA approval in 2004 for the treatment of first-line MCRC based on data from two different clinical trials. Results from subsequent trials continued to support the use of Avastin for clinical management of MCRC.
Contrast this to breast cancer, where Avastin underwent the FDA’s accelerated approval program based on promising results from one clinical trial as well Avastin’s demonstrated efficacy in treating other types of cancer, including colorectal cancer. Full approval of Avastin for breast cancer was contingent upon results from other trials that were ongoing at the time, which ultimately did not show any benefit for these patients and instigated the FDA’s removal of approval for Avastin in treating breast cancer.
As a scientist, it is interesting to speculate as to why Avastin is efficacious in treating MCRC patients but not breast cancer patients from a molecular point of view. Because some breast cancer patients did respond to taking Avastin, it’s possible a subset of breast cancer patients exists whose tumors share a similar molecular profile predictive of response to Avastin. Notably, about 10-15% of MCRC patients respond to treatment with Avastin, suggesting that even amongst MCRC patients there is a subset of individuals sharing a similar molecular profile predictive of a positive response to Avastin.
Bottom line: for some colorectal cancer patients, Avastin in combination with chemotherapy will be an effective treatment regimen, but at this point in time a patient won’t know if Avastin will work for him/her unless they try taking it. For those patients who fail to respond to Avastin, there are other FDA approved drugs to try as well as many promising investigational drugs being tested in clinical trials.
My hope for the future is that through the coordinated efforts of scientists and clinicians, we can start identifying biomarkers that predict response to Avastin so that patients and oncologists alike can start making molecularly informed decisions about treatment plans for patients fighting colorectal cancer.