Positive new Phase III results for Enhertu

Updated results for Enhertu (trastuzumab deruxtecan) for the treatment of patients with HER2 positive metastatic breast cancer from the DESTINY-Breast03 and DESTINY-Breast02 Phase III trials have been presented at the 2022 San Antonio Breast Cancer Symposium by the UK’s AstraZeneca (LSE: AZN) and its partner Japan’s Daiichi Sankyo (TYO: 4568).

In the key secondary endpoint analysis of overall survival (OS) in DESTINY-Breast03, Enhertu demonstrated a 36% reduction in risk of death versus T-DM1 (hazard ratio [HR] = 0.64; 95% confidence interval [CI] 0.47-0.87; p=0.0037). In both treatment arms, median OS was not yet reached (Enhertu [40.5-NE] versus T-DM1 [34.0-NE]) after a median duration of follow-up of 28.4 months for Enhertu and 26.5 months for T-DM1. In the ENHERTU arm, an estimated 77.4% of patients were alive at two years (95% CI: 71.7-81.2) compared to 69.9% of patients treated with T-DM1 (95% CI: 63.7-75.2).

The observed survival benefit was consistent across all analyzed subgroups, including patients with or without baseline brain metastases, with or without baseline visceral disease, those who were hormone receptor (HR) positive or HR negative and patients regardless of prior pertuzumab or lines of systemic therapy.