The FDA approved the antibodydrug conjugate ado-trastuzumab emtansine (Kadcyla), referred to as T-DM1 during clinical research, for patients with HER2-positive, metastatic breast cancer who were previously treated with trastuzumab (Herceptin) and taxane chemotherapy.
Ado-trastuzumab emtansine was reviewed under the FDA’s priority review program.
Richard Pazdur, MD, Director of the Office of Hematology and Oncology Products in the FDA’s Center for Drug Evaluation and Research said “[The new treatment] delivers the drug to the cancer site to shrink the tumor, slow disease progression, and prolong survival. It is the fourth approved drug that targets the HER2 protein.”
The safety and effectiveness of ado-trastuzumab emtansine were evaluated in a clinical study of 991 patients randomly assigned to receive ado-trastuzumab emtansine or lapatinib (Tykerb) plus capecitabine (Xeloda). Patients received treatment until either the cancer progressed or the side effects became intolerable. The study was designed to measure progression-free survival and overall survival.
Results showed that patients treated with ado-trastuzumab emtansine had a median progression-free survival of 9.6 months compared to 6.4 months in patients treated with lapatinib plus capecitabine. The median overall survival was 30.9 months in the ado-trastuzumab emtansine group and 25.1 months in the lapatinib plus capecitabine group.
The most common side effects reported in patients treated with ado-trastuzumab emtansine were nausea, fatigue, pain in the muscles or joints, thrombocytopenia, increased levels of liver enzymes, headache, and constipation.
Ado-trastuzumab emtansine is being approved with a Boxed Warning alerting patients and health care professionals that the drug can cause liver toxicity, heart toxicity and death. The drug can also cause severe life-threatening birth defects, and pregnancy status should be verified prior to starting treatment. ■