Metzger O, Lambertini C, Krop I, Phillips G, Perou C, Symmans F, Melero I, Harbeck N, Winer E, Im S, Barrios C, Bonnefoi H, Gralow J, Ellis P, Gianni L, Toi M, Swain S, Boulet T, Song C, de Haas S. 42O Biomarker analysis from KAITLIN, a randomised phase III study of adjuvant trastuzumab emtansine (TDM-1; K) plus pertuzumab (P) versus trastuzumab (H) plus taxane (T) plus P after anthracyclines (AC) for high-risk HER2-positive early breast cancer (EBC). Annals Of Oncology 2021, 32: s37-s38. DOI: 10.1016/j.annonc.2021.03.056.Peer-Reviewed Original Research