Katherine Queen of Persistent Disease.

Mary Queen of Scots wasn’t the only titular feminist feature released last week. KATHERINE has been scooping all the big headlines out of the San Antonio Breast Cancer Symposium, and for good reason. Analogous to the CREATE-X trial establishing a benefit with adjuvant Xeloda for women with residual HER2(-) breast cancer following neoadjuvant chemo, the phase 3 KATHERINE trial tried adjuvant T-DM1 for residual HER2(+) disease. Almost 1500 women with residual disease after a taxane + trastuzumab were randomized to adjuvant trastuzumab versus T-DM1 monotherapy, each given concurrent to adjuvant radiation when indicated. The primary endpoint of disease-free survival at 3 years was significantly increased from 77 → 88%. Worth noting are rates of radiation pneumonitis which, while small, were doubled with T-DM1 from 0.7 → 1.5%. TBL: Adjuvant T-DM1 rather than trastuzumab is now recommended for women with residual disease following neoadjuvant chemo to effectively halve their risk of recurrence or death. | von Minckwitz, N Engl J Med 2018