In contrast, previous toxicity studies in non–tumor-bearing monkeys for antibody drugs targeting cancer cell surface antigens such as HER2 (trastuzumab, Herceptin; NOAEL: 59 mg/kg/dose) and CD20 (rituximab, Rituxan; NOAEL ≥20 mg/kg/dose) had indeed shown toxicity (interview form of Herceptin, Chugai Pharmaceutical Co. Ltd.; interview form of Rituxan, Chugai Pharmaceutical Co., Ltd.). This evidence concerns the gene ERBB2 and cancer.