Officials with the FDA have approved ado-trastuzumab emtansine (Kadcyla, Genentech) for post-surgery treatment of people with HER2-positive early breast cancer (EBC) who have residual invasive disease after neoadjuvant taxane and trastuzumab (Herceptin)-based treatment.

“This approval is a significant treatment advance for HER2-positive early breast cancer,” said Sandra Horning, MD, chief medical officer and head of Global Product Development, in a prepared 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.”

Neoadjuvant treatment is given before surgery with the goal of shrinking tumors and helping to improve surgical outcomes. Adjuvant treatment is given after surgery and aims to eliminate any remaining cancer cells in the body to help reduce the risk of the cancer returning.

The FDA rapidly reviewed and approved Genentech’s application under the FDA’s Real-Time Oncology Review (RTOR) and Assessment Aid pilot programs, leading to an approval 12 weeks after completing the submission. For this indication, ado-trastuzumab emtansine was also granted Breakthrough Therapy Designation, which is designed to expedite the development and review of medicines intended to treat serious or life-threatening diseases.

This approval is based on results of the Phase III KATHERINE , an international, multi-center, 2-arm, randomized, open-label, Phase III study showing ado-trastuzumab emtansine significantly reduced the risk of invasive breast cancer recurrence or death from any cause (invasive disease-free survival; iDFS) by 50% (HR=0.50, 95% CI 0.39-0.64, p<0.0001) compared to trastuzumab as an adjuvant treatment in people with HER2-positive EBC who have residual invasive disease after neoadjuvant taxane and trastuzumab-based treatment.

At 3 years, 88.3% of people treated with ado-trastuzumab emtansine did not have their breast cancer return compared to 77.0% treated with trastuzumab, an absolute improvement of 11.3%. People who have residual disease after neoadjuvant treatment have a worse prognosis than those with no detectable disease.

The most common Grade 3 or higher side effects (>2%) with ado-trastuzumab emtansine in the KATHERINE study were decreased platelet count and high blood pressure. The most common adverse effects (>25%) with 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 or feet; and joint pain.


FDA Approves Genentech's Kadcyla for Adjuvant Treatment of People With HER2-Positive Early Breast Cancer With Residual Invasive Disease After Neoadjuvant Treatment [news release]. South San Francisco, CA; May 3, 2019: Genetech. Accessed May 3, 2019.