Carvedilol in Preventing Heart Failure in Childhood Cancer Survivors

PRIMARY OBJECTIVE: I. To determine the impact of a two-year course of low-dose carvedilol on surrogate echocardiographic indices of heart failure (HF) risk, including: Left ventricular (LV) posterior wall thickness-dimension ratio (LV T-D); LV systolic and diastolic function, and afterload; Natriuretic peptides, troponins, and galectin-3. SECONDARY OBJECTIVES: I. To establish safety and tolerability of this two-year course of low-dose carvedilol, assessing both objective measures (hepatic function) and patient reported outcomes. II. To examine the modifying effect of demographic, clinical, and molecular characteristics on the risk: benefit ratio from this two-year carvedilol intervention. EXPLORATORY OBJECTIVE: I. To evaluate the long-term efficacy of carvedilol in preventing cardiomyopathy and/or heart failure in high-risk childhood cancer survivors. OUTLINE: This is a dose-escalation study. Patients are randomized to 1 of 2 treatment arms. ARM I: Patients receive low-dose carvedilol orally (PO) once daily (QD) or twice daily (BID) for 24 months. ARM II: Patients receive placebo PO QD or BID for 24 months. After completion of study treatment, patients are followed up for 3 years.