Negative in Ames, human lymphocyte chromosome aberration and rat bone marrow micronucleus assays
“Fostemsavir was not genotoxic in the bacterial reverse mutation assay (Ames test in Salmonella and E. coli), a chromosome aberration test in human lymphocytes, and rat bone marrow micronucleus test.”
2-year rat and 26-week transgenic mouse: no statistically significant tumor increases
“In a 2-year carcinogenicity study conducted in rats and a 26-week carcinogenicity study conducted in transgenic mice, fostemsavir produced no statistically significant increases in tumors over controls.”
Rat EFD: cleft palate and other craniofacial malformations at maternally toxic 1,000 mg/kg/day
“Teratogenic effects occurred in rats at the maternally toxic dose of 1,000 mg/kg/day, such as cleft palate, open eyes, shortened snout, microstomia, misaligned mouth/jaw, and protruding tongue (SF =144).”
Not genotoxic overall: Ames negative; in vitro chromosome aberration positive without (not with) metabolic activation; rat micronucleus and comet negative