This phase II placebo-controlled study will evaluate the effect of carvedilol, compared to placebo, on anthracycline/anti-HER2 therapy induced left ventricular dysfunction in patients with HER2-positive breast cancer who are receiving adjuvant or neoadjuvant therapy. All patients will undergo routine cardiac surveillance with 2D echocardiograms per standard of care at multiple time points which will align as closely as possible to the following: pre-anthracycline (baseline), pre-anti-HER2 therapy, and 3, 6, 9, and 12 months (+/- 4 weeks) after initiation of anti-HER2 therapy. In the case that standard of care echocardiograms are not done at these time points, either due to a delay in anti-cancer therapy or due to the patient's medical condition, the principal investigator will determine if the standard of care echocardiogram may be used in lieu of one of the time points listed. Additional speckle tracking strain analysis will be performed on these echocardiograms, and blood specimens will be drawn at several time points for biomarker analysis.
After completion of anthracycline treatment and prior to initiation of anti-HER2 therapy, 32 patients with abnormal myocardial strain, defined as global longitudinal strain \< 19% or % change from baseline by \> 11%, will be randomized in a 1:1 ratio to carvedilol versus placebo. Carvedilol will be administered twice daily for approximately 1 year OR until the end of anti-HER2 therapy, if it is discontinued prior to 1 year. Treatment in both carvedilol and placebo groups will be systematically up-titrated at weeks 3, 6, and 9 (+/- 1 week) after randomization to a goal dose of 25mg twice daily.
