Negative in Ames, in vitro chromosome aberration and rat bone marrow micronucleus assays
“Relugolix was not mutagenic in vitro in the bacterial reverse mutation (Ames) assay nor clastogenic in the in vitro chromosomal aberration assay and in vivo rat bone marrow micronucleus assay.”
✓ VerifiedFDA multi-discipline review, p. 35Source ↗
Carcinogenicity
2-year mouse and rat: not carcinogenic
“Two-year carcinogenicity studies were conducted in mice at oral relugolix doses up to 100 mg/kg/day and in rats at doses up to 600 mg/kg/day. Relugolix was not carcinogenic in mice or rats at exposures up to approximately 75 or 224 times, respectively, the human exposure at the recommended dose of 120 mg daily based on AUC.”
Rabbit EFD: embryo-fetal lethality at 9 mg/kg/day (~0.3x human exposure)
“In an embryo-fetal development study in rabbits, oral administration of relugolix during the period of organogenesis resulted in embryo-fetal lethality at the highest dose tested, 9 mg/kg/day (approximately 0.3 times the human exposure at the recommended dose of 120 mg daily based on AUC).”
✓ VerifiedFDA multi-discipline review, p. 34Source ↗
Safety pharmacology
No CNS/respiratory effects in rats up to 2000 mg/kg; hERG IC50 9.7 µg/mL; QTc prolongation up to 47 msec in monkeys at ≥100 mg/kg
“In safety pharmacology studies, there were no relugolix-related adverse effects on the central nervous and respiratory systems in rats at doses up to 2000 mg/kg. While relugolix was a low-potency hERG blocker in vitro (IC50 = 9.7 µg/mL), a single dose of relugolix in monkeys resulted in QT/QTc prolongation of up to 47 msec at ≥ 100 mg/kg (90 times the human Cmax based on toxicokinetics from a 4-week repeat-dose monkey study).”
✓ VerifiedFDA multi-discipline review, p. 32Source ↗
Not genotoxic overall: Ames negative; in vitro chromosome aberration positive without (not with) metabolic activation; rat micronucleus and comet negative