Download 「智慧炸彈」，這種名為T-DM1的實驗藥物療法有助於抑制癌細胞，延長

抗乳癌「智慧炸彈」 可望年內上市
美聯社芝加哥電
醫學界宣布成功研發一種可對抗乳癌的「智慧炸彈」，這種名為 T-DM1 的實驗藥物療法有助
於抑制癌細胞，延長病患壽命，而且藥物的副作用也較輕。
北卡羅來納州杜克大學的醫學團隊是在芝加哥舉行癌症研討會上發表這份報告，這項有 991 名
後期病患參與的主要研究顯示，T-DM1 療法可使癌細胞不致惡化擴散，有時甚至會萎縮，因而
使得病患的病情至少可穩定幾個月。
研究人員是結合抗癌藥「賀癌平」(Herceptin)與化學治療，合製成 T-DM1 雙重治療法，過程中
使用的化療殺傷力相當大，不能單獨使用，但配合「賀癌平」之後，便可把療效集中於癌細胞。
實驗團隊讓 991 名病患測試 T-DM1 的效果，結果發現病情在 10 個月後才會惡化，時間遠超過
其他治療法的六個月。副作用也僅有少數病患出現肝臟受損、血栓風險增加等，但大多數人並
未出現化療常見的副作用，沒有脫髮和嘔吐。
更要的是，該療法似乎可提高病人的存活率，在治療後兩年，65%接受該療法的病患仍然在世，
另一組服用一般癌症藥物的病患，則僅 47%在世。
至於該藥物可讓病患延長存活多久，研究人員需要更長時間進一步研究，以及收集更多資料。
事實上，許多使用新療法的病患仍在世，使得研究人員還無法計算出平均延長存活時間。
領導該研究的杜克大學醫生金柏莉‧布萊克維爾(Kimberly Blackwell)表示：「針對這些病患可延
長存活的時間，絕對差異已超過一年，這是非常重大的進展。」另外，研究人員指出，這種藥
物目前仍在試驗階段，專家希望最快可在一年內可上市。
Drug Combination Offers Hope In Fighting Breast Cancer
Jun 4, 2012
(USA TODAY) Doctors today will unveil the results of the first large trial of a new kind of "precision
medicine" against breast cancer: a drug combination designed to act like a smart bomb, which delivers
its payload directly to tumor cells while reducing collateral damage to the rest of the body.
The experimental drug, T-DM1, doesn't cure anyone.
But it attacks breast cancer in a whole new way - one that may be useful against a variety of other
tumors - and appears significantly better at controlling cancer than the current standard of care, says
Kimberly Blackwell, who presents her findings today in Chicago at the annual meeting of the
American Society of Clinical Oncology.
T-DMI combines the drug Herceptin, a man-made antibody, with an old-fashioned chemotherapy drug
called emtansine, Blackwell says.
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Herceptin, approved in 1998, was designed to block growth signals from a protein found almost
exclusively on cancer cells called HER2, says Sandra Horning, global head of development at
Genentech, the drug's developer. Herceptin homes in on HER2 proteins, binds to them and blocks them
from transmitting run-away growth signals. To create T-DM1, scientists attached chemotherapy
molecules to Herceptin, hanging them like ornaments on a Christmas tree. When T-DM1 is infused
into the body, Herceptin zeroes in on HER2 proteins and releases its "payload" of toxin directly at the
cancer cell. The toxin then enters the cancer cell and kills it, Horning says.
That's a big change from traditional chemo, in which controlled doses of poison are infused into the
bloodstream. While chemo kills cancer cells, it also kills healthy tissues, too, often causing grueling
side effects of nausea, vomiting and fatigue, as well as life-threatening infections.
Doctors tested T-DM1 in a study of nearly 1,000 women with advanced cancers who had been on
Herceptin, but who are no longer benefitting from it. All of the women had breast cancers that make
lots of HER2.
T-DM1 kept these women's cancers in check for 9.6 months, about three months longer than standard
therapy, which combines the anti-cancer pills Tykerb and Xeloda, according to the study.
Doctors also noticed a trend suggesting that women randomly assigned to take T-DM1 live longer, as
well. After two years, 65% of those on T-DM1 were alive, compared to 48% of those on Tykerb and
Xeloda.
"It's a major advance," says Jo Anne Zujewski, a breast cancer researcher at the National Cancer
Institute, who was not involved in the study. "I'm excited for women."
People should be cautious about overestimating T-DM1's survival advantage, because, statistically, it's
possible that those findings could be due to chance, Horning says. As researchers continue to monitor
the women's progress, doctors will get a better sense if T-DM1 really improves survival.
Louis Weiner, director of the Georgetown Lombardi Comprehensive Cancer Center in Washington,
says breast cancer patients are in great need of new treatment options. While Herceptin has helped
many women, most breast cancer patients with advanced disease eventually relapse, he says.
Breast cancer patient Shirley Mertz, 65, says she's also glad to see women with another option. She
knows women who don't respond well to standard treatments, or who find the side effects intolerable,
says Mertz, who lives in the Chicago area and takes Herceptin for advanced breast cancer that recurred
in spite of an earlier mastectomy.
T-DM1 has generated enormous excitement among breast cancer patients, says Mertz, a board member
of an advocacy group called the Metastatic Breast Cancer Network. Women's main frustration, she
says, is that it's not yet widely available. Because T-DM1 is experimental, it's available only through
clinical trials, Horning says. Genentech plans to apply for Food and Drug Administration approval
later this year. Genentech, which plans to test T-DM1 in early breast cancer, has not yet announced
how much T-DM1 will cost. Herceptin alone, in the doses currently used to treat breast cancer, costs
thousands of dollars a month.
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Blackwell says she's pleased that women on T-DM1 almost never suffer from the nausea, diarrhea or
hair loss that's typical of chemo. In the study, 41% of those taking T-DM1 had serious side effects,
compared to 57% of those on standard therapy.
The drug used in T-DM1, emtansine, is an incredibly potent poison, Blackwell says. Early tests
showed it was far too toxic to be used in people, at least when given in a typical intravenous infusion.
But doctors can administer very strong doses by targeting its poison directly at cancer cells, she says.
Zujewski says she hopes this technique will catch on.
Genentech is testing eight similar antibody-drug combinations in the clinic, with 25 in its research
pipeline, Horning says.
"It does lead me to believe that more molecules are going to be developed that will work this way," she
says.
Weiner notes that doctors are already using other man-made antibodies to fight cancer, including the
drugs Erbitux and Rituxan. These drugs could find additional uses, if researchers can successfully
attach chemo molecules to them, too, he says.
"We talk a lot about developing a cancer bomb," Blackwell says. "This is an example of delivering that
bomb to the cancer, not the patient."
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