A Phase IV, Open-Label, Single-Arm Study of Prophylaxis for Datopotamab Deruxtecan-related Stomatitis in Eligible Patients With Metastatic or Inoperable Locally Recurrent Breast Cancer or Locally Advanced or Metastatic Epidermal Growth Factor Receptor-Mutated Non-Small Cell Lung Cancer (TROPION-SWISH)

The purpose of this Phase IV study is to describe the incidence and severity of Dato-DXd treatment-emergent grade ≥ 2 stomatitis in participants receiving prophylactic dexamethasone mouthwash within the first 12 weeks of study treatment (ie, Dato-DXd dosing). The study will enroll an estimated 100 participants across approximately 35 sites in the U.S. Enrollment of participants is planned to occur over approximately 18 months, with a minimum of 12 weeks of follow-up for each participant after the first Dato-DXd dose. This study has one arm, and the study population will consist of 2 independ…