Adjuvant Trastuzumab Emtansine Versus Paclitaxel in Combination With Trastuzumab for Stage I HER2-Positive Breast Cancer (ATEMPT): A Randomized Clinical Trial

In the July 20, 2021 edition of Journal of Clinical Oncology, Sara Tolaney and colleagues report on the results of the ATEMPT trial.


The purpose of the ATEMPT trial was to determine if treatment with trastuzumab emtansine (T-DM1) causes less toxicity compared to paclitaxel plus trastuzumab (TH) while delivering acceptable invasive disease-free survival (iDFS) among patients with early stage IE stage I human HER-2/neu positive breast cancer .


In this clinical trial, patients with stage I HER-2/neu + breast cancer were randomized in a 3:1 fashion to T-DM1 or TH and were treated with T-DM1 3.6 mg/kg IV every 3 weeks for 17 cycles or paclitaxel 80 mg/m2 IV with trastuzumab once every week × 12 weeks (4 mg/kg load →2 mg/kg), followed by trastuzumab × 39 weeks (6 mg/kg once every 3 weeks). The co-primary objectives were to compare the incidence toxicities in patients treated with T-DM1 versus paclitaxel–rituximab and to evaluate iDFS in patients receiving Ado-trastuzumab emtansine


The population available for analysis included all 497 patients who initiated protocol therapy (383 T-DM1 and 114 trastuzumab–paclitaxel).  Clinically relevant toxicities were documented in 46% of patients on T-DM1 and 47% of patients on paclitaxel–trastuzumab (P = .83). The 3-year iDFS for Ado-trastuzumab emtansine was 97.8% (95% CI, 96.3 to 99.3).this resulted in a rejection of the null hypothesis (P < .0001). Serially collected patient-reported outcomes indicated that patients treated with Ado-trastuzumab emtansine had less alopecia and neuropathy with better work productivity versus trastuzumab–paclitaxel


The authors concluded “

Among patients with stage I HER2+ BC, one year of adjuvant T-DM1 was associated with excellent 3-year iDFS, but was not associated with fewer CRT compared with TH. “