Max S. Mano, MD, PhD
The invasive disease-free survival (iDFS) benefit with adjuvant ado-trastuzumab emtansine (T-DM1; Kadcyla) versus trastuzumab (Herceptin) in patients with HER2-positive early breast cancer who had residual invasive disease following neoadjuvant therapy was observed regardless of the type of neoadjuvant chemotherapy (NACT) used. A benefit with T-DM1 was also observed across several high-risk patient populations, according to subgroup analyses from the phase III KATHERINE trial.
The KATHERINE trial included 1486 patients with HER2-positive, nonmetastatic invasive primary breast cancer who were randomized in a 1:1 ratio to adjuvant T-DM1 or trastuzumab. Prior neoadjuvant therapy had to consist of ≥6 cycles of chemotherapy containing a taxane (with or without anthracycline) and ≥9 weeks of trastuzumab.
At the 2019 San Antonio Breast Cancer Symposium (SABCS), lead study author Max S. Mano, MD, PhD, presented a poster with several subanalyses of the trial, including a comparison of patients who received anthracycline (AC)-based NACT versus those who received non-AC–based NACT.
The HR for iDFS was 0.51 (95% CI, 0.38-0.67) and 0.43 (95% CI, 0.22-0.82) favoring T-DM1 for the AC and non-AC groups, respectively. In the AC arm, the 3-year iDFS rates were 87.4% with T-DM1 versus 75.7% with trastuzumab. In the non-AC arm, the 3-year iDFS rates were 91.7% versus 81.4%, respectively.
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