Risk Summary

There are no available data on GEMTESA use in pregnant women to evaluate for a drug-associated risk of major birth defects, miscarriage, or adverse maternal or fetal outcomes.

In animal studies, no effects on embryo-fetal development were observed following administration of vibegron during the period of organogenesis at exposures approximately 275-fold and 285-fold greater than clinical exposure at the recommended daily dose of GEMTESA, in rats and rabbits, respectively. Delayed fetal skeletal ossification was observed in rabbits at approximately 898-fold clinical exposure, in the presence of maternal toxicity. In rats treated with vibegron during pregnancy and lactation, no effects on offspring were observed at 89-fold clinical exposure. Developmental toxicity was observed in offspring at approximately 458-fold clinical exposure, in the presence of maternal toxicity. No effects on offspring were observed at 89-fold clinical exposure (see Data).

The background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies carry some risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2-4% and 15-20%, respectively.

Data

Animal Data

In an embryo-fetal developmental toxicity study, pregnant rats were treated with daily oral doses of 0, 30, 100, 300, or 1000 mg/kg/day vibegron during the period of organogenesis (Days 6 to 20 of gestation). These doses were associated with systemic exposures (AUC) 0-, 9-, 89-, 275-, and 1867-fold higher, respectively, than in humans treated with the recommended daily dose of GEMTESA. No embryo-fetal developmental toxicity was observed at doses up to 300 mg/kg/day. Treatment with the high dose of 1000 mg/kg/day was discontinued due to maternal toxicity.

In an embryo-fetal developmental toxicity study, pregnant rabbits were treated with daily oral doses of 0, 30, 100, or 300 mg/kg/day vibegron during the period of organogenesis (Days 7 to 20 of gestation). These doses were associated with systemic exposures (AUC) 0-, 86-, 285-, and 898-fold higher, respectively, than in humans treated with the recommended daily dose of GEMTESA. No embryo-fetal developmental toxicity was observed at doses of vibegron up to 100 mg/kg/day. Maternal toxicity (decreased food consumption), reduced fetal body weight, and an increased incidence of delayed skeletal ossification, were observed at 300 mg/kg/day.

In a pre- and post-natal developmental toxicity study, pregnant or lactating rats were treated with daily oral doses of 0, 30, 100, or 500 mg/kg/day vibegron from day 6 of gestation through day 20 of lactation. These doses were associated with estimated systemic exposures (AUC) 0-, 9-, 89-, and 458-fold higher, respectively, than in humans treated with the recommended daily dose of GEMTESA. No developmental toxicity was observed in F1 offspring at doses up to 100 mg/kg/day. Maternal toxicity was observed during lactation (decreased body weight gain) at doses ≥100 mg/kg/day and during gestation (decreased body weight gain and food consumption) at 500 mg/kg/day. Developmental toxicity was observed in F1 offspring (increased stillborn index, lethality, reduced viability and weaning indices, decreased body weight and body weight gains, low physical development differentiation indices, and effects on sensory function and reflexes) at 500 mg/kg/day.