Tag Archives: t-dm1

T-DM1 Approved For Her2 Breast Cancer

Photo courtesy of freedigitalphotos.net and antpkr
Photo courtesy of freedigitalphotos.net and antpkr

T-DM1 Approved For Her2 Breast Cancer
Further to my post of August 15, 2012, New Chemotherapy Drug for HER2 – Genentech’s T-DM1, I have an update for you.  The FDA has finally approved T-DM1, now known as the brand-name Kadcyla, for women with HER2+, metastatic breast cancer. The new therapy has been approved for use in patients who have already undergone unsuccessful treatment with a combination of trastuzumab (Herceptin) and a taxane. 
An Interesting Method of Delivery

Kadcyla is a conjugate – it combines the drug trastuzumab, better known by the brand name Herceptin, and a powerful chemotherapy drug called DM1.  The trastuzumab portion targets HER2+ cells, then the attached chemotherapeutic molecule – the DM1, which is too toxic to deliver directly into the patient’s bloodstream – is delivered and attacks the cancer cell.   T-DM1 has helped inspire a new generation of antibody + drug conjugates.

Study Results

FDA approval was based on a study known as EMILIA, in which patients with HER2+, metastatic breast cancer who had failed treatment with a combination of trastuzumab and taxane were randomized to ado-trastuzumab emtansine or conventional therapy with lapatinib and capecitabine (Xeloda).  The patients given ado-trastuzumab emtansine resulted in significant improvements in both progression-free survival (9.6 vs 6.4 months) and overall survival (30.9 vs 25.1 months). 

The Down-Side (Why Is There Always A Down-Side?)

This sounds like really great news, however, the drug is not without risk (what else is new?).  The FDA requires labeling on Kadcyla to warn of risks of liver toxicity, reductions in left ventricular ejection fraction for the heart, and death.  In addition, there is risk of severe birth defects, so a woman’s pregnancy status should be determined before starting treatment, the FDA said.  The most common side effects associated with the drug were nausea, fatigue, musculoskeletal pain, thrombocytopenia, elevated liver enzymes, headache, and constipation.

As if all of that weren’t enough, the drug will cost $9,800 a month, or about $94,000 for a 9.5-month course of therapy.  Let’s hope it can keep people alive.





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New Chemotherapy Drug for HER2+: Genentech’s T-DM1

In June of this year, the results of a new study were released by Duke Cancer Institute for a breast cancer drug known as T-DM1 which is made by Genentech, a unit of Roche, who sponsored the trial.

I didn’t write an article about it at the time because I wanted to do a little more research.

How T-DM1 Works

T-DM1 is designed for those who are HER2 positive, meaning that their tumors have high levels of a protein called HER2.

T-DM1 works a little differently than most chemotherapy drugs.  It consists of toxins that are linked to proteins called antibodies.  The antibodies latch onto cancer cells and deliver their toxic payload directly into the cancer cells.  This is termed an antibody-drug conjugate.

More specifically, to make T-DM1, trastuzumab, the T in the name, is attached to DM1, a toxin more potent than the typical chemotherapy drug.

The trastuzumab latches onto cells with the HER2 protein protruding from their surface and is taken inside the cells.  Once inside, the antibody degrades and sets the toxin free. Although the toxin is still connected to the linker, it is still able to kill the cells.

According to the research, by doing this, side effects are supposedly reduced.

Study Results

The T-DM1 trial involved 991 women with metastatic breast cancer whose cancer was getting worse despite previous treatment with the drug Herceptin (also a Genentech drug) and taxane.  Half of the women in the study got T-DM1 and the other half received two drugs that are now commonly used for such patients — Tykerb, also known as lapatinib, and Xeloda, also known as capecitabine.

According to the study results, T-DM1 delayed the worsening of disease by about three months.  For those who received T-DM1, the median time before the disease progressed was 9.6 months, compared with 6.4 months for those getting the two other drugs.

While it is too early to state that T-DM1 prolonged lives (because not enough time had elapsed since the beginning of the trial and the release of the results), researchers were pretty confident that it would be beneficial.

T-DM1 Side Effects

I have been active in several breast cancer forums and I know of a few women who have been on the T-DM1 trials.  Here’s what some of them have had to say about side effects of T-DM1:

  • Neutropenia – neutrophils are a class of white blood cells in your immune system and neutropenia means a low count of neutrophils
  • Significant aching and stiffness of muscle and joints, pain and cramping – worse in hands and feet
  • Mouth sores, dry mouth
  • Drippy nose, sometimes bloody
  • Liver enzyme elevation
  • Cardiomyopathy
  • Fatigue
  • Lung inflammation
  • Heavy periods (if not menopausal)

I thought you might like to know.  To me, that list of side effects sounds a whole lot like most chemotherapy drugs but if they are keeping people alive and giving them hope, that’s always a good thing.

I’ll get excited when researchers come up with effective drugs that don’t have side effects.

Reference articles:




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