FDA Approves Ado-Trastuzumab Emtansine for HER2+ Breast Cancer Treatment

The Food and Drug Administration (FDA) approved ado-trastuzumab emtansine (Kadcycla) for the adjuvant treatment of patients with HER2-positive early breast cancer who have residual invasive disease and have received a neoadjuvant taxane and trastuzumab (Herceptin)-based treatment, according to Genentech, the manufacturer of the antibody-drug conjugate.

“This approval is a significant treatment advance for HER2-positive early breast cancer. By working closely with the FDA and participating in the Real-Time Oncology Review pilot program, we are able to make Kadcyla available for people with residual invasive disease after neoadjuvant therapy much sooner than anticipated,” said Sandra Horning, M.D., chief medical officer and head of Global Product Development at Genentech, in a statement. “With every step forward in reducing the risk of disease recurrence, we come closer to the goal of helping each person with early breast cancer have the greatest opportunity for cure.”

The approval is based off results from the phase III multi-center, two-arm, randomized KATHERINE study, where 743 patients were given ado-trastuzumab emtansine and 743 patients were given trastuzumab. Results showed that ado-trastuzumab emtansine significantly reduced the risk of invasive breast cancer recurrence or death by 50% (HR, 0.50; 95% CI 0.39-0.64; P <.0001) when compared with trastuzumab for patients with HER2-positive early breast cancer with residual invasive disease after neoadjuvant taxane and trastuzumab therapy.

After 3 years, 88.3% of patients on ado-trastuzumab emtansine did not have a breast cancer recurrence — an 11.3% improvement from the 77% of patients given trastuzumab.

The most common grade 3 or higher adverse event (AE) that occurred in at least 2% of patients were decreased platelet count and high blood pressure. A higher percentage of patients on ado-trastuzumab emtansine experienced grade 3 or higher AEs compared to those on trastuzumab (26% versus 15%, respectively).

The most common all-grade AEs (>25%) from ado-trastuzumab emtansine were: fatigue, nausea, increased blood levels of liver enzymes, musculoskeletal pain, bleeding, decreased platelet count, headache, numbness, tingling, or pain in the hands and feet, and arthralgia.