In a 2-year oral carcinogenicity study in rats, abrocitinib increased the incidence of benign thymomas in female rats at doses of 10 and 30 mg/kg/day (2.8 and 14 times the MRHD, respectively, based on AUC comparison). Abrocitinib was not carcinogenic in female rats at 3 mg/kg/day (0.6 times the MRHD based on AUC comparison) or male rats at doses up to 30 mg/kg/day (14 times the MRHD based on AUC comparison). Abrocitinib was not carcinogenic in Tg.rasH2 mice at oral doses up to 60 mg/kg/day in males and 75 mg/kg/day in females.
Abrocitinib was not mutagenic in the bacterial mutagenicity assay (Ames assay). Although abrocitinib was aneugenic in the in vitro TK6 micronucleus assay, abrocitinib was not aneugenic or clastogenic in an in vivo rat bone marrow micronucleus assay.
Abrocitinib did not impair male fertility at doses up to 70 mg/kg/day (26 times the MRHD based on AUC comparison) or female fertility at 10 mg/kg/day (2 times the MRHD based on AUC comparison). Abrocitinib impaired female fertility (reducing fertility index, corpora lutea, and implantation sites) at 70 mg/kg/day (29 times the MRHD based on AUC comparison). Impaired fertility in female rats reversed 1 month after cessation of abrocitinib administration.
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