• This is the first dataset of T-DXd monotherapy and T-DXd + pertuzumab as first-line treatment for HER2+ mBC
• T-DXd monotherapy (N=75) and T-DXd + pertuzumab (N=50) showed robust efficacy:
  • Confirmed ORR was 76.0% and 84.0% for T-DXd monotherapy and T-DXd + pertuzumab, respectively
  • Median DOR was not reached for T-DXd monotherapy or T-DXd + pertuzumab
  • PFS rate at 12 months was 80.8% and 89.4% for T-DXd monotherapy and T-DXd + pertuzumab, respectively; the number of PFS events is small and most patients were censored
• There are 62.7% and 56.0% of patients receiving ongoing study treatment, with a median duration of follow up of 23.9 months and 25.3 months, in the T-DXd monotherapy and T-DXd + pertuzumab modules, respectively
• Encouraging clinical activity was observed with T-DXd monotherapy and T-DXd + pertuzumab in first-line HER2+ mBC, irrespective of disease status and HR status

• The safety profiles of T-DXd and pertuzumab were consistent with their individual known profiles
  • The incidence of ILD/pneumonitis events was 9.3% and 14.0% in the T-DXd monotherapy and T-DXd + pertuzumab modules, respectively; there were no ILD/pneumonitis-related deaths in either module
• T-DXd monotherapy and T-DXd + pertuzumab are being evaluated versus THP, in patients with HER2+ mBC in the first-line setting, in the Phase 3 DESTINY-Breast09 clinical trial

Document ID: 325e86bc-2a1f-401a-b8d6-fa304896a85b
Last updated: 14-February-2023