Safety of Continuing HER-2 Directed Therapy in Overt Left Ventricular Dysfunction

SCHOLAR-2 is a Phase II open-label randomized controlled trial with blinded outcome event ascertainment with a target sample size of 130. Control Group Recommendations for continuing or holding trastuzumab, pertuzumab, or trastuzumab-emtansine (T-DM1) for the control group are guided by an adaptation of the 2008 Canadian recommendations. Intervention Group The intervention group will continue to receive trastuzumab, pertuzumab, or trastuzumab-emtansine (T-DM1) in the setting of asymptomatic decline in LVEF up to an LVEF of 40% as outlined in the criteria listed in Table 3. For reasons of practicality, in the intervention group, the first dose of trastuzumab, pertuzumab, or trastuzumab-emtansine (T-DM1) after randomization can be administered up to 3 weeks late. This will allow time for the participant to be reviewed by a cardiologist and to receive ACE-I/angiotensin receptor blocker and/or beta-blocker, and for dose titration. Study assessments will occur: 1. 3 weeks after randomization 2. 6 weeks after randomization 3. Follow-up at every 3 months thereafter until 12 months after the last dose of trastuzumab, pertuzumab, or trastuzumab-emtansine (T-DM1)