Trastuzumab deruxtecan alone or with pertuzumab for previously untreated HER2-postive metastatic breast cancer

Trastuzumab deruxtecan, alone or in combination with pertuzumab, is in clinical development for previously untreated human epidermal growth receptor 2 (HER2)-positive metastatic breast cancer. Breast cancer is cancer that starts in the breast tissue. HER2-positive breast cancer means that the cancer cells express more of the HER2 protein on their surface. HER2 encourages cell growth and therefore HER2-
positive cancers can grow more quickly. Metastatic HER2-positive breast cancer occurs when the cancer cells have spread to another part of the body, most commonly the bones, lungs, brain, or liver. Many patients with HER2-positive metastatic breast cancer eventually develop resistance to treatment underscoring the need for novel therapies to delay the emergence of resistance and provide better clinical
outcomes, improve quality of life, and prolong survival in frontline settings.