Negative in Ames, mouse lymphoma and rat micronucleus assays
“Difamilast was negative in a standard battery of genotoxicity tests, including the Ames test, the mouse lymphoma assay, and an in vivo micronucleus study in rats.”
✓ VerifiedFDA multi-discipline review, p. 40Source ↗
Carcinogenicity
2-year dermal rat and mouse: no drug-related tumors (3.7-10x MRHD AUC)
“In 2-year dermal carcinogenicity studies in rats and mice, no test article-related neoplastic findings were observed in rats or mice that received difamilast at dermal doses up to 3% (3.7 to 10 times the MRHD based on AUC comparison).”
✓ VerifiedFDA multi-discipline review, p. 40Source ↗
Reproductive & developmental
Rat EFD at 100 mg/kg/day: fewer live fetuses, lower fetal weight, retarded ossification, ventricular septum defects
“In embryofetal development studies, fewer live fetuses, decreased fetal weight, retarded ossification, and increased membranous ventricular septum defect were noted in rats at the high dose of 100 mg/kg/day.”
✓ VerifiedFDA multi-discipline review, p. 40Source ↗
Safety pharmacology
No CNS (rat) or cardiovascular/respiratory (dog) effects at single SC doses; hERG IC50 2.54 µM
“There were no significant effects on the central nervous system (CNS) in rats at single SC doses up to 200 mg/kg or cardiovascular or respiratory parameters in conscious dogs at single SC doses up to 30 mg/kg. In an in vitro human Ether-à-go-go Related Gene (hERG) assay, the half-maximal inhibitor concentration (IC50) value for the inhibition on hERG K+ current was 2.54 μM.”
✓ VerifiedFDA multi-discipline review, p. 39Source ↗
Not genotoxic overall: Ames negative; in vitro chromosome aberration positive without (not with) metabolic activation; rat micronucleus and comet negative