A phase III study of trastuzumab emtansine (T-DM1) + pertuzumab versus trastuzumab + pertuzumab + taxane, after anthracyclines as adjuvant therapy for high-risk HER2-positive early breast cancer (EBC)

Abstract No : 500

Indication : Her2 Positive Breast Cancer

Intervention : trastuzumab emtansine (T-DM1) + pertuzumab

Company : Roche

Technology : Monoclonal antibody


KAITLIN did not meet its co-primary endpoints. In LN+ patients (n = 1658), there was no significant difference between arms in IDFS event risk (stratified hazard ratio = 0.97; 95%CI 0.71–1.32). Three-year IDFS was 94.1% with AC-THP and 92.7% with AC-KP. Results were similar in the ITT population (stratified hazard ratio = 0.98; 95%CI 0.72–1.32; 3-year IDFS: 94.2% vs 93.1%). OS data are immature with an event rate of ~4%–5% in each arm. During the study overall, there was a similar incidence of grade $3 AEs (55.4% vs 51.8%) and SAEs (23.3% vs 21.4%) with AC-THP and AC-KP, respectively. More patients receiving AC-KP than AC-THP discontinued T-DM1 or trastuzumab, respectively, because of AEs (26.8% vs 4.0%). PRO data will be presented.


Replacing adjuvant taxane and trastuzumab with T-DM1 did not result in significantly improved efficacy or overall safety. Nonetheless, in this high-risk population, a favorable IDFS outcome was achieved in both study arms. HP + chemotherapy remains the standard of care for patients with high-risk HER2-positive EBC.


Combining T-DM1 to Pertuzumab in early breast cancer is not effective. Hence, it can't be a good combination in this setting.

Refer to Her2 Positive Breast Cancer Market report for detailed Insights.