ASCO20: Adding T-DM1 to Targeted Therapy for High-Risk Early Breast Cancer
Posted: Monday, June 1, 2020
Nadia Harbeck, MD, PhD, of the University of Munich, Germany, and colleagues found that replacing adjuvant taxane and trastuzumab with trastuzumab emtansine (T-DM1) did not improve efficacy or overall safety in high-risk populations with HER2-positive early breast cancer, in the phase III KAITLIN trial. However, they reported a “favorable” invasive disease–free survival with both T-DM1 and trastuzumab combination regimens, during the ASCO20 Virtual Scientific Program (Abstract 500).
The study enrolled a total of 1,846 patients with HER2-positive breast cancer, with excised tumors either lymph node–positive or lymph node–negative and greater than 2 cm. The study had two primary endpoints: invasive disease–free survival in lymph node–positive patients and application of hierarchical testing in the intention-to-treat populations. Within 9 weeks of surgery, patients received either 3 or 4 cycles of anthracycline-based chemotherapy followed by 18 cycles of T-DM1 plus pertuzumab or taxane (AC-KP) and concurrent trastuzumab plus pertuzumab (AC-THP).
KAITLIN did not meet either primary endpoint. There was no significant difference in the invasive disease–free survival between treatment groups in the 1,658 patients with lymph node–positive disease (stratified hazard ratio = 0.97) nor in the intention-to-treat patient population (stratified hazard ratio = 0.98). The 3-year invasive disease–free survival was 92.7% with AC-KP and 94.1% with AC-THP.
The rates of grade ≥ 3 adverse events for each treatment group were also comparable: 51.8% with AC-KP and 55.4% with AC-THP. Furthermore, 21.4% of those treated with AC-KP and 23.3% of those treated with AC-THP experienced a serious adverse event. Overall survival data were immature at the time of the presentation. In addition, more patients who received T-DM1 than the trastuzumab regimen discontinued treatment because of toxicity (26.8% vs. 4.0%).
Disclosure: For full authors’ disclosures, visit coi.asco.org.
