As usual, there’s more to the story than you’ll get from a newspaper headline. These are some of the headlines about Avastin we saw this week:
- Avastin Before Breast Cancer Surgery Could Help Save Lives
- Breast cancer drugs’ effectiveness doubted by UM study
- Avastin fights early breast cancer in 2 studies
- Avastin’s Failure in Breast Cancer: New Study May Explain Why It Happened
With headlines like those, no wonder people are confused about what progress we’re making in breast cancer treatment. Here’s the real story.
The FDA revoked Avastin’s approval for treating late stage breast cancer in November 2011, saying the drug didn’t extend life and can cause dangerous side effects—we’d been advocating for the revocation of Avastin for breast cancer for several years on these grounds.
Two new studies published this week in the New England Journal of Medicine explored the use of Avastin in conjunction with chemotherapy before surgery to shrink early stage breast cancer tumors. These studies present intriguing, yet inconclusive, results.
The U.S. study, led by Dr. Harry Bear of Virginia Commonwealth University, treated 1,200 women with either chemotherapy or chemotherapy plus Avastin before surgery. In 28% of women treated with chemotherapy alone, no evidence of tumors was found; in women treated with chemotherapy plus Avastin, that number was 34%. The German study, although using different chemotherapy drugs, found no evidence of tumors at the time of surgery in 18% in those treated with Avastin vs. 15% of those on chemotherapy alone. These findings indicate Avastin may shrink tumors prior to surgery better than chemotherapy alone.
What’s still unknown, however, is whether Avastin will help improve overall survival for the group treated with it. Slowing tumor growth does not necessarily mean women will live longer than they otherwise would have. Unfortunately, other studies and other drugs have shown tumor shrinkage only to find the cancer returns and there is no overall impact on survival. It’s important that both of these studies continue to track the health of these women so we can get more answers over time. Since Avastin also has serious side effects, such as risk for heart problems and bleeding, it’s also important to show a benefit that exceeds the risk of the drug. We need to wait for more information before declaring whether Avastin actually provides a true step forward in early stage disease.
Which brings us to the third study in the news this week, published in the Proceedings of the National Academy of Sciences by Max Wicha, MD and colleagues at the University of Michigan in Ann Arbor. This study starts to shed some light on why we see promises and then get disappointments with drugs, like Avastin, that are given to women with breast cancer to block tumor growth. These researchers transferred human tumor cells to mice and treated them with Avastin. They found that Avastin slowed tumor growth but also increased cancer stem cell growth. The lack of oxygen to the dying tumors actually caused a concentration of cancer stem cell markers that might explain the later growth of cancer in patients treated with Avastin, even after showing tumor shrinkage. Much more work needs to be done in this area to understand the true clinical implications.
The three new studies we saw on Avastin this week leave us with more questions than definitive answers. We hope ongoing follow-up and further studies will allow researchers to better understand the long-term survival implications of Avastin use with early stage breast cancer patients and give us better treatment options than we have today.