Avastin has been in the news a lot lately, and most of the press has been negative. In November, the FDA revoked its approval of Avastin to treat newly diagnosed metastatic breast cancer. Then, in December, Genentech, who manufactures Avastin, announced it would not seek FDA approval for the treatment of ovarian cancer, based on studies showing an improvement in progression-free survival but not overall survival. Of course, whether Avastin helps women with ovarian cancer remains a controversial question, depending how you value progression-free survival. Compare this report with this one, for example.
In tomorrow's New England Journal of Medicine, there are two reports of clinical trials evaluating Avastin for patients with newly diagnosed HER2-negative breast cancer. In both this study and this one, women with newly diagnosed breast cancer were given chemotherapy with or without Avastin. The women with HER2-negative tumors had a higher rate of "pathological complete response" if they received Avastin. "Pathologic complete response" means that when it was time for surgery, not living tumor could be found. Women with a "pathologic complete response" tend to live longer than women who do not respond as well.
What does all this mean? Will these studies "reignite the debate" about Avastin in breast cancer? I guess that depends on who is doing the debating. I think the role of Avastin in breast cancer, indeed the role of Avastin in treating any cancer, remains unclear. In the end, I believe it will be shown that Avastin helps some cancer patients and not others, and it will all depend on the biology of each tumor type. Clearly, not all breast cancer is the same, and breast cancer is not the same as ovarian cancer, let alone osteosarcoma or lymphoma. Today's studies simply reinforce the fallacy of extrapolating from one tumor type to another. A drug may be very helpful for one type of cancer, and useless for another.
That's why we do clinical trials like this one, sponsored by St. Jude Children's Research Hospital, in which we are participating, trying to see if Avastin helps osteosarcoma patients.
These studies do raise another important point, which I will discuss very soon. These studies relied on a "surrogate end point." That is, the studies were designed to see an effect on "pathologic complete response," but only because that is thought to correspond with improved overall survival. Only time will tell whether the women who received Avastin do actually live longer.
More to come...
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