Kadcyla Significantly Improves Treatment of HER 2 + Early Stage Breast Cancer

KATHERINE clinical trial update: Kadcyla precision cancer medicine improves survival in HER2 + early stage breast cancer

by Dr. C.H. Weaver M.D. updated 12/2018

The precision cancer medicine Kadcyla® (trastuzumab emtansine) significantly reduced the risk of breast cancer recurring in people with HER 2-positive early stage breast cancer (ESBC) with residual disease after neoadjuvant treatment. The complete results of the trial were updated at the 2018 San Antonio Breast Cancer Symposium.

About Kadcyla

HER2 is a protein involved in normal cell growth. Approximately 25% of breast cancers over-express (make too much of) the HER2 protein, and this over-expression contributes to cancer cell growth and survival. HER2 targeted therapies such as Herceptin have dramatically improved outcomes for women with HER2-positive breast cancer, but researchers continue to explore new approaches to treatment.

Kadcyla combines Herceptin and a chemotherapy drug (DM1) that interferes with cancer cell growth. Kadcyla delivers Herceptin and DM1 directly to HER2-positive cells, and limits exposure of the rest of the body to the chemotherapy. Kadcyla has already been approved or the treatment of more advanced HER2-positive breast cancer.

The KATHERINE clinical trial evaluated women with HER2-positive ESBC who did not achieve a pathological complete response to neoadjuvant treatment. Neoadjuvant treatment is given before surgery with the goal of providing immediate treatment and to shrink the cancer for easier surgical removal. In the KATHERINE clinical trial nearly 1500 women were treated with either Kadcyla or Herceptin as an adjuvant therapy in patients with residual cancer in the breast and/or axillary lymph nodes following neoadjuvant treatment with Herceptin and taxane-based chemotherapy and directly compared.

Overall 77% of patients who received Herceptin compared to 88.3% of patients who received Kadcyla were alive without evidence of cancer progression 3 years from treatment. This represents an absolute increased improvement of 11% for patients treated with Kadcyla.


  1. Geyer CE, Huang CS, Mano MS, et al. Phase III study of trastuzumab emtansine (T-DM1) vs trastuzumab as adjuvant therapy in patients with HER2-positive early breast cancer with residual invasive disease after neoadjuvant chemotherapy and HER2-targeted therapy including trastuzumab: Primary results from KATHERINE. Oral presentation at: 2018 San Antonio Breast Cancer Symposium; December 4-8, 2018; San Antonio, TX.
  2. Minckwitz GV, Huang CS, Mano MS, et al. Trastuzumab emtansine for residual invasive HER2-positive breast cancer [published online December 5, 2018]. N Engl J Med. doi: 10.1056/NEJMoa1814017