Find Information About:

Drugs & Supplements

Get information and reviews on prescription drugs, over-the-counter medications, vitamins, and supplements. Search by name or medical condition.

Pill Identifier

Pill Identifier

Having trouble identifying your pills?

Enter the shape, color, or imprint of your prescription or OTC drug. Our pill identification tool will display pictures that you can compare to your pill.

Get Started
My Medicine

My Medicine

Save your medicine, check interactions, sign up for FDA alerts, create family profiles and more.

Get Started

WebMD Health Experts and Community

Talk to health experts and other people like you in WebMD's Communities. It's a safe forum where you can create or participate in support groups and discussions about health topics that interest you.

  • Second Opinion

    Second Opinion

    Read expert perspectives on popular health topics.

  • Community


    Connect with people like you, and get expert guidance on living a healthy life.

Got a health question? Get answers provided by leading organizations, doctors, and experts.

Get Answers

Sign up to receive WebMD's award-winning content delivered to your inbox.

Sign Up

Breast Cancer Health Center

Font Size

'Magic Bullet' Drug Delays Breast Cancer Worsening

T-DM1 Spares Women From Some, But Not All, Serious Side Effects
WebMD Health News
Reviewed by Laura J. Martin, MD

June 4, 2012 (Chicago) -- A new targeted cancer drug delayed the worsening of metastatic breast cancer, possibly with fewer side effects than traditional treatments, according to results of a late-stage study.

Called T-DM1, the new drug combines Herceptin with a potent chemotherapy drug. It's been called a "magic bullet": Herceptin homes in on cancer cells and delivers the cancer-killing agent directly to its target without damaging nearby cells.

The study involved nearly 1,000 women with metastatic breast cancer that was continuing to get worse despite treatment with Herceptin and a common chemotherapy drug.

Half the women got T-DM1 and the other half got Tykerb and Xeloda, a standard treatment for women who aren't helped by Herceptin.

T-DM1 delayed the time to the disease progressing by about three months. Among women who received T-DM1, the average time before the disease got worse was about nine-and-a-half months vs. about six-and-a-half months for those getting the standard drugs.

Although a few months might not sound like much, it can be a huge gain for seriously ill patients who are running out of options, say doctors studying the drug.

It is still too early to know for sure that T-DM1 will prolong lives, but the early data suggest that it will, says researcher Kimberly Blackwell, MD, of Duke University.

For the most part, women taking T-DM1 did not suffer the often debilitating side effects associated with chemotherapy, such as diarrhea, nausea, vomiting, and hair loss, she tells WebMD.

Still, the drug is not without toxicity: About 41% of women on T-DM1 suffered a serious side effect vs. 57% of those getting standard treatment.

About 13% of women getting T-DM1 had lowered blood platelet counts, which can increase the risk of bleeding. But there were very few cases of bleeding.

The findings were presented here at the annual meeting of the American Society of Clinical Oncology.

How T-DM1 Works

About 20% of breast cancer patients have an aggressive form of the disease known as HER2-positive tumors. Herceptin, a man-made antibody, binds to and blocks part of the HER2 protein that appears on the surface of some breast cancer cells. It revolutionized the way this type of tumor was treated when it was approved in the late 1990s.

Today on WebMD

Breast Cancer Overview
From self-exams and biopsies to reconstruction, we’ve got you covered.
Dealing with breast cancer
Get answers to your questions.
woman having mammogram
Experts don’t agree on all fronts, but you can be your own advocate.
woman undergoing breast cancer test
Many women worry. But the truth? Most abnormalities aren’t breast cancer.
Breast Cancer Treatments Improving
Resolved To Quit Smoking
Woman getting mammogram
Screening Tests for Women
ovarian cancer overview slideshow
serious woman
what is your cancer risk
10 Ways to Revitalize Slideshow