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Duke doctors drop 'smart bomb' on breast cancer

Posted June 3, 2012
Updated June 4, 2012

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— Duke Cancer Institute doctors have successfully dropped the first "smart bomb" on breast cancer, using a drug to deliver a toxic payload to tumor cells while leaving healthy ones alone.

In a key test involving nearly 1,000 women with a very advanced stage of the disease, the experimental treatment extended by several months the time women lived without their cancer getting worse, doctors planned to report Sunday at a cancer conference in Chicago.

More importantly, the treatment seems likely to improve survival, although it will take more time to know for sure. After two years, 65 percent of women who received it were still alive versus 47 percent of those in a comparison group given two standard cancer drugs.

That margin fell just short of the very strict criteria researchers set for stopping the study and declaring the new treatment a winner, and they hope the benefit becomes more clear with time. In fact, so many women on the new treatment are still alive that researchers cannot yet determine average survival for the group.

"The absolute difference is greater than one year in how long these people live," said the study's leader, Dr. Kimberly Blackwell, director of Duke's Breast Cancer Clinical Program. "This is a major step forward."

A warning to hopeful patients: The drug is still experimental, so it is not available for widespread use yet. Its backers hope it can reach the market within a year.

The treatment builds on Herceptin, the first gene-targeted therapy for breast cancer. It is used for about 20 percent of patients whose tumors overproduce a certain protein.

Researchers combined Herceptin with a chemotherapy so toxic that it can't be given by itself, plus a chemical to keep the two linked until they reach a cancer cell where the poison can be released to kill it.

This double weapon, called T-DM1, is the "smart bomb." It's actually not all that smart; Herceptin isn't a homing device, just a substance that binds to breast cancer cells once it encounters them.

"This is a more targeted way of delivering chemotherapy," Blackwell said. "It delivers the drug directly to the cancer cells, while avoiding cells that don't really need to receive chemotherapy, which keeps patients from getting sick."

Doctors tested T-DM1 in 991 women with widely spread breast cancer that was getting worse despite treatment with chemotherapy and ordinary Herceptin. They were given either T-DM1 infusions every three weeks or infusions of Xeloda plus daily Tykerb pills, the only other treatments approved for such cases.

The median time until cancer got worse was nearly 10 months in the women given T-DM1 versus just over six months for the others. That is about the same magnitude of benefit initially seen with Herceptin, which later proved to improve overall survival, too, Blackwell said.

T-DM1 caused fewer side effects than the other drugs did. Some women on T-DM1 had signs of liver damage and low levels of factors that help blood clot, but most did not have the usual problems of chemotherapy.

"People don't lose their hair. They don't throw up. They don't need nausea medicines. They don't need transfusions," said Blackwell, who has consulted in the past for Genentech, the study's sponsor.

"The data are pretty compelling," said Dr. Michael Link, a pediatric cancer specialist at Stanford University who is president of the American Society of Clinical Oncology, the group hosting the Chicago conference where the results were being presented.

"It's sort of a smart bomb kind of therapy, a poison delivered to the tumor ... and not a lot of other collateral damage to other organs," he said.

Dr. Louis Weiner, director of Georgetown Lombardi Comprehensive Cancer Center, said the results strongly suggest T-DM1 improves survival. It delivers more drug directly to tumors with less side effects, "a clear advance," he said.

Denise Davis, 51, a customer service representative at a propane company, was diagnosed three years ago with breast cancer that had spread to her liver and bones. Since February 2011, the Lynchburg, Va., woman has traveled two hours to Duke every three weeks to get infusions of T-DM1.

"I call it 'Herceptin-plus,'" she said. Scans every six weeks show "everything is still shrinking or stable," she said. "Right now, I'm feeling pretty good about it. The only way I'd feel a little better is if it took care of everything, but I'll take what I can get."

The study will form the basis for Genentech, part of the Swiss company Roche, to seek approval later this year to sell the drug in Europe and the United States. Another company, ImmunoGen Inc., made the technology combining the drugs.

Genentech says the price of T-DM1 has not been determined. Herceptin costs more than $4,000 a month plus whatever doctors charge to infuse it. Herceptin's U.S. patent doesn't expire until 2019.

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Online:

Cancer conference: http://www.cancer.net

American Cancer Society: http://www.cancer.org

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Marilynn Marchione can be followed at http://twitter.com/MMarchioneAP

12 Comments

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  • lucasd06 Jun 6, 2012

    "You just said the reason why there is no cure for the top 3 or so dis eases in the world...MONEY....There are cures out there but the governments won't put them out for they want money,same with the medical profession...if there was a cure it would put many doctors who mommy and daddy want their kiddies to grow up to be...out of work. There are cures in Europe but the U.S. and the g8 nations won't acknowledge them." Uhavenoclu

    That is the most absurd statement I've heard in a while! How would you know there are cures already out there? You must have some sort of insider knowledge.....Don't you think if your statement was accurate, more people would have heard about it, especially patients dealing with cancer? Don't be so ignorant. Take your apathetic synicism elsewhere.

  • Uhavenoclu Jun 4, 2012

    Well, it's exciting to see the technology advance, especially for cancer. I hope that over time the price becomes more affordable.

    You just said the reason why there is no cure for the top 3 or so dis eases in the world...MONEY....There are cures out there but the governments won't put them out for they want money,same with the medical profession...if there was a cure it would put many doctors who mommy and daddy want their kiddies to grow up to be...out of work.
    There are cures in Europe but the U.S. and the g8 nations won't acknowledge them.

  • smstaff Jun 4, 2012

    That's not a "smart bomb". This is a smart bomb.

    http://www.awmi.net/extra/healing/weiskopf

    "Although she had been prayed for, Connie underwent surgery a short time later. Following the procedure, during which a surgeon removed a portion of her left breast, the doctor called and said, "We don't know what happened, there was no cancer left." Connie said, "I know what happened. God healed me!" David and Connie praised God and rejoiced in Him!"

  • superflames Jun 4, 2012

    Well, it's exciting to see the technology advance, especially for cancer. I hope that over time the price becomes more affordable.

    It appears that with this drug you get a 2 out of 3 chance of surviving at least 2 more years - which would cost $96,000 over that 2 years just for the Herceptin, not knowing the additional cost for the rest of the drug.

    Well, it is still exciting to read of advances like this.

  • charmcclainlovesdogs2 Jun 4, 2012

    What a great discovery! This will help millions of women/men with breast cancer. This is what the Relay for Life monies do.

  • SueInNC Jun 4, 2012

    It takes more than 1 year for a drug to reach the market...that's too bad.

  • yellowhorses Jun 4, 2012

    $4000/mo for Herceptin. Well that certainly takes it out of reach for every person that has no health insurance. Probably takes it out of reach of a lot of women who have insurance that will not pay or will only pay part.

    And before you all take off and blame it on Obama, stop and think about all the business schools who have trained the current generation of big business leaders of the drug companies, the banks, stockbrokers .........

  • mpheels Jun 4, 2012

    yankee1 - The research may have happened at a private organization, but it was largely funded with federal grants. In fact, most of the gains in medical science in the past 100+ years are the result of federally funded research.

  • storchheim Jun 4, 2012

    That's OK, yankee1, we can rely on Europe to develop new drugs and bring them to market without the obstacles presented by the FDA. And we'll slip further down the slope in the global economy.

  • yankee1 Jun 4, 2012

    Which Government agency developed this again? I seem to have missed it's name. Same goes for GSK's new find!! Wait'll you see what Obamacare does to innovation and experimentation. You'll be dreaming about the old days!!!!

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