ERBB2 and heart failure: For instance, in the SafeHer (A Safety and Tolerability Study of Assisted and Self-Administered Subcutaneous [SC] Herceptin [Trastuzumab] as Adjuvant Therapy in Early Human Epidermal Growth Factor Receptor 2 (HER2)–Positive Breast Cancer) phase 3 study of subcutaneous trastuzumab for the treatment of HER2-positive early breast cancer, grade ≥3 cardiac disorders were reported in 0.9%, including heart failure in 0.3% of patients, with low event rates both for patients treated with sequential or concurrent chemotherapy.41