On May 3, 2019, the U.S. Food and Drug Administration (FDA) approved the targeted therapy Kadcyla (chemical name: T-DM1 or ado-trastuzumab emtansine) to treat early-stage HER2-positive breast cancer after surgery if there were cancer cells found during surgery (residual disease) after treatment with a taxane chemotherapy and Herceptin (chemical name: trastuzumab) before surgery.
Doctors call treatments given after surgery adjuvant treatments. Doctors call treatments given before surgery neoadjuvant treatments.
One way doctors judge the effectiveness of neoadjuvant chemotherapy is to look at the tissue removed during surgery to see if any actively growing cancer cells are present. If no active cancer cells are present, doctors call it a “pathologic complete response” or pCR. If there are cancer cells present in the tissue removed, this cancer is called “residual disease.”
Taxol (chemical name: paclitaxel), Taxotere (chemical name: docetaxel), and Abraxane (chemical name: albumin-bound or nab-paclitaxel) are taxane chemotherapy medicines.
The FDA approval was based on 2018 results from the KATHERINE trial, which found that Kadcyla offered better disease-free survival compared to Herceptin in people diagnosed with early-stage, HER2-positive breast cancer who had residual disease after neoadjuvant chemotherapy that included a taxane and Herceptin or Herceptin and Perjeta (chemical name: pertuzumab).
Disease-free survival is how long a person lives without the cancer coming back.
Kadcyla is a combination of Herceptin and the chemotherapy medicine emtansine. Emtansine, like some other chemotherapy medicines, disrupts the way cells grow. Emtansine isn’t a targeted medicine, so it can affect healthy cells as well as cancer cells.
Kadcyla was designed to deliver emtansine to cancer cells in a targeted way by attaching emtansine to Herceptin. Herceptin then carries emtansine to the HER2-positive cancer cells.
Kadcyla is given intravenously, which means the medicine is delivered directly into your bloodstream through an IV or port. Kadcyla usually is given every 3 weeks in a doctor’s office.
Kadcyla is approved by the FDA to treat:
- HER2-positive metastatic breast cancer that has previously been treated with Herceptin and taxane chemotherapy
- HER2-positive early-stage breast cancer after surgery if there is residual disease after neoadjuvant chemotherapy that includes a taxane and Herceptin
Kadcyla side effects
The most common side effects of Kadcyla are:
- bone and joint pain
- muscle pain
- low blood platelet count
- nerve damage
- low red blood cell count
- low potassium levels
Kadcyla also can cause other serious side effects. While these serious side effects are rare (about 1–2% of people treated with Kadcyla will experience them), it’s important to know about them:
- Heart problems: Kadcyla may cause serious heart problems, including some that don’t have symptoms, such as reduced heart function, and some that do have symptoms, such as congestive heart failure. Symptoms to watch for include swelling of the ankles or legs, shortness of breath, cough, or weight gain of more than 5 pounds in less than 24 hours.
- Lung problems: Kadcyla may cause inflammation of the lungs, which can be life-threatening. Symptoms include trouble breathing, cough, tiredness, and fluid in the lungs.
- Liver problems: Kadcyla may cause severe liver problems, including liver failure. Symptoms include swelling or pain in the abdomen, a yellow tint in the eyes or skin (jaundice), and swollen legs, feet, or ankles.
What this means for you
If you’ve been diagnosed with early-stage, HER2-positive breast cancer and did not have a pathologic complete response to treatment before surgery with taxane chemotherapy and Herceptin, you and your doctor are likely considering treatment options for the residual disease. You may want to ask your doctor whether treatment with Kadcyla makes sense for your unique situation.
For more information, visit the Breastcancer.org Kadcyla pages.
Written by: Jamie DePolo, senior editor
Reviewed by: Brian Wojciechowski, M.D., medical adviser