Trastuzumab emtansine for residual invasive HER2-positive breast cancer

For women with HER2-positive early breast cancer who had residual invasive disease after completion of neoadjuvant therapy with a trastuzumab-containing regimen, new research shows that the likelihood of recurrence of invasive breast cancer or death was significantly lower with adjuvant trastuzumab emtansine (T-DM1) compared with trastuzumab alone.

For women with HER2-positive early breast cancer who had residual invasive disease after completion of neoadjuvant therapy with a trastuzumab-containing regimen, new research shows that the likelihood of recurrence of invasive breast cancer or death was significantly lower with adjuvant trastuzumab emtansine (T-DM1) compared with trastuzumab alone. An interim analysis of the Phase III, open-label KATHERINE trial found that invasive disease or death occurred in 12.2% (91 patients) in the T-DM1 group and 22.2% (165 patients) in the trastuzumab group. Additionally, the estimated percentage of patients who were free of invasive disease at 3 years was 88.3% in the T-DM1 group vs. 77.0% in the trastuzumab group. The data show that invasive disease-free survival was substantially higher in the T-DM1 group compared with the trastuzumab group, while distant recurrence as the first invasive-disease events occurred in 10.5 of the T-DM1 group and 15.9% of the trastuzumab group. A higher percentage of patients in the T-DM1 group experienced adverse events, which is consistent with the drug's known safety profile, compared with trastuzumab alone.