PGR and metastasis: Prespecified subgroup analyses of ORR showed consistent results across subgroups as follows (Fig. 3): age (younger than 65 = 24.2%, 65 or older = 19.6%), response to T-DM1 (CR/PR/SD = 24.0%, PD = 19.8%), T-DM1 best response (resistance = 25.7%, refractory = 20.9%), ER status (positive = 23.1%, negative = 24.2%), PgR status (positive = 21%, negative = 23.4%), the presence of visceral metastasis (with metastasis = 22.6%, without metastasis = 23.1%), and treatment line before T-DM1 (fewer than two = 26.4%, two or more = 20.7%).