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  3. The FDA may rescind its approval of Avastin, a colon-cancer drug. If the s

The FDA may rescind its approval of Avastin, a colon-cancer drug. If the s

游客2024-11-08  6
问题    The FDA may rescind its approval of Avastin, a colon-cancer drug.
   If the summer of 2009 was the season of "death panels", as the debate over health-care reform exploded, this is the season of "17.5k dead women a year". That’s the body count scaremongers are predicting if the Food and Drug Administration rescinds its provisional approval of the drug Avastin for metastatic breast cancer, a decision expected by year’s end. Although the move has nothing to do with the new health-care law, uncertainty about "Obama-care" has given opponents an opening to terrify people about what’s coming—like bureaucrats rationing health care to save money.
   The reality is far different and, for those who care more about helping cancer patients than about scoring political points, much sadder. That’s because in 2008, when the FDA gave "fast track" approval for Avastin in breast cancer that has metastasized—usually to the lungs, bones, liver, or brain—it was conditional on the manufacturer, Genentech, running additional clinical trials of the drug’s safety and efficacy. There was a good reason for that. Avastin is an angiogenesis inhibitor, a class of cancer drugs that have not lived up to their hype: although they stop one mechanism by which malignant cells grow blood vessels to sustain them, the cells often activate a different mechanism and go on proliferating.
   Although Avastin does extend the lives of patients with metastatic colorectal and kidney cancer, and remains FDA-approved for those uses, the new studies show it does not work the same miracle against metastatic breast cancer (MBC). Instead, Avastin increased what’s called progression-free survival (how long before cancer spreads or grows) by about one to three weeks, depending on which chemo agent it was paired with. But it did not keep women alive any longer than chemo alone. To some advocates, progression-free survival without an increase in overall survival is still welcome, since it suggests patients have a better quality of life during their last months.
   But it’s hard to make that case for Avastin. Not only did it not keep women alive, but it also caused hypertension, hemorrhaging, bowel perforations, and other side effects. "It seems as if the drug’s toxicity cancels out any benefit, " cancer surgeon David Gorski of the Karmanos Cancer Institute told me. Perforated bowels do not equal a better quality of life.
   These dismal results are what led an FDA panel to vote 12-1 in July to rescind the conditional approval of Avastin for MBC. Critics of health-care reform, predictably, saw nefarious motives—in particular, evidence that Obamacare will ration expensive drugs. (Avastin costs some $88, 000 a year, though few patients live that long.) The Wall Street Journal editorialized about the "Avastin mugging", and Sen. David Vitter accused the FDA of "assigning a value to a day of a person’s life".
   If Avastin did extend lives for, let’s say, $10, 000 a day, Vitter might have a case. But it doesn’t extend life at all. That makes allegations like the 17, 500 dead women (from a right-wing blog) "utter demagoguery of the most vile and despicable sort, " Gorski wrote on the blog Science-Based Medicine.
   There are stories galore of women with metastatic breast cancer who are alive "because of Avastin". Indeed, patients have been flooding the airwaves and blogosphere with claims that Avastin helped them. But the only way to tell whether Avastin deserves the credit for keeping patients alive is through large studies. "There are always patients who live longer than average, " biostatistician Donald Berry of the MD Anderson Cancer Center told me. "They attribute it to the treatment; people love to make attributions." But when the proportion of patients alive at any given time in a study is the same whether they are receiving Avastin or not—as the two large trials found—then crediting Avastin is "very likely wrong". "That some women did live longer on Avastin, " Berry explained, "may simply reflect the natural heterogeneity of the disease and say nothing about the therapy."
   Doctors can keep prescribing Avastin for metastatic breast cancer off-label, though insurers will not pay for it. Some activists welcome that. There is "no evidence of clinical benefit from Avastin, yet there is harm, " says Fran Visco, president of the National Breast Cancer Coalition. "We need to demand more of treatment before we unleash it on the public." Science-based medicine isn’t always pretty. But it’s better than politics-based medicine, which is what some critics of the Avastin decision are practicing—and much better than deluding ourselves into thinking something works when it doesn’t. [br] Which of the following is NOT the benefit of Avastin?
选项 A、It can help malignant cells grow blood vessels to sustain them.
B、It can extend the lives of patients with metastatic colorectal and kidney cancer.
C、It can extend the lives of patients with breast cancer.
D、It can help patients have a better quality of life during their last months.
答案 C
解析 下列哪项不是阿瓦斯丁的益处?首先，要看清题目，找出不正确的选项。所给的三个选项A、B和D分别可从第三段和第四段中得出均为正确的答案，而阿瓦斯丁不能延长乳腺癌病人的生命。
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