The confirmed partial response occurred in a participant with HR+/HER2− breast cancer with liver and bone metastases at screening, an ECOG performance status of 0, and 4 prior lines of therapy (including a cyclin-dependent kinase 4/6 inhibitor, hormonal therapy, and chemotherapy); TTR was 1.9 months per both BICR and investigator assessment, and OS was 24 months. This evidence concerns the gene CDK4 and breast carcinoma.