Ado-trastuzumab emtansine (Kadcyla, Genentech) has received FDA approval for the adjuvant treatment of patients with human epidermal growth factor receptor 2 (HER2)-positive early breast cancer (EBC) who have residual invasive disease after neoadjuvant taxane and trastuzumab-based treatment, according to a press release.
Ado-trastuzumab emtansine is currently the only antibody-drug conjugate approved for the treatment of HER2-positive early and metastatic breast cancer, according to Genentech. The therapy combines 2 anti-cancer agents using HER2-targeting trastuzumab and the chemotherapy agent DM1. Patients with EBC may be treated before and after surgery as part of a comprehensive treatment approach to reduce the risk of cancer recurrence.
The application was rapidly reviewed and approved 12 weeks after completed submission under the FDA’s Real-Time Oncology Review and Assessment Aid pilot programs. Ado-trastuzumab emtansine was also granted Breakthrough Therapy Designation for this indication.
The approval is based on data from the phase 3 KATHERINE study, which evaluated the safety and efficacy of ado-trastuzumab emtansine versus trastuzumab (Herceptin) as an adjuvant therapy in patients with HER2-positive EBC who have pathological invasive residual disease in the breast and/or axillary lymph nodes following neoadjuvant therapy that included trastzumab and taxane-based chemotherapy.
For the study, patients were randomized to receive either ado-trastuzumab emtansine 3.6 mg/kg intravenously or trastuzumab 6 mg/kg intravenously on day 1 of a 21-day cycle for 14 cycles. According to the results, 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 with trastuzmab as an adjuvant treatment after a median follow-up of 40 months.
At 3 years, 88.3% of those treated with ado-trastuzumab emtansine did not experience disease recurrence compared with 77% treated with trastuzumab, an absolute improvement of 11.3%, according to the data.
The most common serious adverse effects with ado-trastuzumab emtansine included decreased platelet count and high blood pressure. Common adverse effects reported in the study 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.
Additionally, patients should be selected for treatment with ado-trastuzumab emtansine based on an FDA-approved companion diagnostic. The FDA also approved the Ventana Medical Systems, Inc PATHYWAY anti-HER-2/neu (4B5) Rabbit Monoclonal Primary Antibody assay and the INFORM HER2 Dual ISH DNA Probe Cocktail assay.
“This approval is a significant treatment advance for HER2-positive early breast cancer,” Sandra Horning, MD, chief medical officer and head of Global Product Development, said in a statement. “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. 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 care.”