Neratinib was not carcinogenic in a 6-month study in Tg.rasH2 transgenic mice when administered daily by oral gavage at doses up to 50 mg/kg/day in males and 125 mg/kg/day in females. A 2-year carcinogenicity study in rats with oral neratinib is ongoing at this time and will be completed as a post-marketing requirement. No neratinib-related neoplastic findings were observed in rats in this study in groups receiving only 1 year of administration at doses up to 10 mg/kg/day.