The rate of New York Heart Association class III or IV congestive heart failure was 4% with trastuzumab alone, 4% with lapatinib alone, and 1% with the combination, differences that were not statistically significant.
Patients in the trastuzumab group were more likely to complete their therapy (78%) than their counterparts in the lapatinib group (68%) and in the combination group (63%) (P = .01).
About half of patients were able to have breast-conserving surgery, whether they received trastuzumab alone (54%), lapatinib alone (46%), or both drugs (50%).
Dr. Robidoux disclosed that he is a consultant to GlaxoSmithKline and receives honoraria and research funding from GlaxoSmithKline and Roche. Dr. von Minckwitz disclosed no relevant conflicts of interest.