Fertility and Embryo-Fetal Development Assessment in Rats and Rabbits with Evacetrapib: A Cholesteryl Ester Transfer Protein Inhibitor.

Background: The purpose of these studies was to evaluate the effects of evacetrapib on male and female fertility and on embryo-fetal development (EFD).

Methods: Evacetrapib, a potent and selective inhibitor of cholesteryl ester transfer protein (CETP), was administered daily by oral gavage starting 2 weeks (for female) or 4 weeks (for male) before mating, during cohabitation, and until necropsy in the male rat fertility study or through gestation day (GD) 17 in the female rat combined fertility/EFD study. For rabbit EFD studies, animals were dosed from GDs 7 to 19 or from 1 week before mating through GD 19. Dose levels of evacetrapib ranged from 60 to 600 mg/kg for rats and from 1 to 100 mg/kg/day for rabbits.

Results: Parental findings in rats included decreased body weight and food consumption and moribund euthanasia in animals given 600 mg/kg/day and decreased food consumption at 300 mg/kg/day. There were no adverse effects on estrus cycling, fertility indices, sperm parameters, maternal reproductive parameters, male reproductive tissue, or fetal viability, growth, or external/visceral morphology. An increase in the incidence of 14th rudimentary ribs, a minor, transient variation considered nonadverse, was the only significant developmental finding in rats given 600 mg/kg/day. Slight decreases in body weight and food consumption at 100 mg/kg/day were the only maternal effects observed in rabbits with no adverse developmental effects noted.

Conclusion: No adverse effects on fertility or EFD were observed in rats at doses up to 600 mg/kg/day and no adverse effects on EFD were noted in rabbits at doses up to 100 mg/kg/day. Birth Defects Research 109:513-527, 2017. © 2017 Wiley Periodicals, Inc.