POOLED ANALYSIS DESTINY-BREAST-01, 02 and -03

This study analysed data from the DESTINY-Breast 01, 02, and 03 trials, focusing on outcomes according to patients’ responses to therapy with T-DXd in HER2+ metastatic breast cancer. DESTINY-Breast 01 included patients treated at later lines, DESTINY-Breast 02 involved mainly third-line patients, and DESTINY-Breast 03 focused on second-line patients. The pooled analysis revealed a 15% complete response rate, 57.2% partial response rate, and 27.8% stable or progressive disease rate.

Patients who achieved a complete response had significantly longer PFS and OS, with a median treatment duration of 27.4 months. Those with partial responses had a median treatment duration of 14 months, while those with stable or progressive disease were treated for only six months. Side effects were consistent with previous reports, including some cases of pneumonitis.

The study concluded that a complete response to T-DXd, which often occurs early in the treatment, is associated with prolonged PFS and OS. Patients with better ECOG scores, no visceral disease, or fewer than three metastatic sites had the highest likelihood of a complete response, although complete responses were observed across various patient subgroups.