Breast Cancer Coverage from Every Angle

Adjuvant Treatment of Early-Stage Breast Cancer: T-DM1 Versus Paclitaxel Plus Trastuzumab

By: Noelle Cutter, PhD
Posted: Tuesday, September 7, 2021

Adjuvant paclitaxel with trastuzumab is a common combination treatment for invasive early breast cancers with overexpression of HER2. In a phase II clinical trial, Sara M. Tolaney, MD, MPH, and colleagues from the Dana-Farber Cancer Institute, Boston, reported that 1 year of adjuvant therapy with trastuzumab emtansine (T-DM1) resulted in “excellent” invasive disease–free survival compared with paclitaxel plus trastuzumab but not a real difference in clinically relevant toxicities. Their results were reported in the Journal of Clinical Oncology.

A total of 494 patients were randomly assigned to receive adjuvant T-DM1 at 3.6 mg/kg every 3 weeks for 17 cycles or paclitaxel at 80 mg/m2 with trastuzumab (4 mg/kg to start, followed by 2 mg/kg intravenously once per week for 12 weeks). After completing 12 weeks of paclitaxel/trastuzumab, patients received 6 mg/kg trastuzumab intravenously every 3 weeks for 13 cycles.

The trial results indicated that in the arm given adjuvant T-DM1, clinically relevant toxicities were experienced in 46% of patients, compared with 47% of patients given paclitaxel/ trastuzumab (P = .83). The 3-year invasive disease–free survival was 97.8% with adjuvant T-DM1 (95% confidence interval [CI] = 96.3%–99.3%), which exceeded the protocol-specified 3-year invasive disease–free survival rate of 95%. In addition, the 3-year rate of freedom from invasive local or regional recurrences, distant recurrences, and any death from breast cancer was 99.2% (95% CI = 98.2%–100%).

Adverse events reported with T-DM1 were thrombocytopenia and elevated bilirubin. In addition, higher rates of neuropathy, neutropenia, alopecia, diarrhea, gastroesophageal reflux disease, decreased white blood cell count, and infusion-related reactions were reported with the combination of paclitaxel and trastuzumab.

“Given the low event rate and improved quality of life associated with trastuzumab emtansine in this study, trastuzumab emtansine may be considered an alternative treatment to paclitaxel plus trastuzumab for patients with stage I HER2-positive disease,” concluded the authors. 

Disclosure: For full disclosures of the study authors, visit

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