US Pharm. 2011;36(9):HS-39-HS-40. 

The first study to investigate the effect of the breast cancer drug trastuzumab (Herceptin) on heart and vascular function in elderly patients has found that it raises the risk of heart problems. This was especially true in women with a history of heart disease, diabetes, or both, the study, published in the cancer journal Annals of Oncology, found. The authors of the study examined records for 45 women aged between 70 and 92 who had been treated with trastuzumab since 2005 and found that 26.7% (12) of the patients developed heart problems caused by the drug. This represents a slightly higher rate than seen in earlier, clinical trials in younger, healthier women.