Risk Summary

Fetal malformations were observed in vaborbactam-treated rabbits, therefore advise pregnant women of the potential risks to the fetus. There are insufficient human data to establish whether there is a drug-associated risk of major birth defects or miscarriages with VABOMERE, meropenem, or vaborbactam in pregnant women.

Malformations (supernumerary lung lobes, interventricular septal defect) were observed in offspring from pregnant rabbits administered intravenous vaborbactam during the period of organogenesis at doses approximately equivalent to or above the maximum recommended human dose (MRHD) based on plasma AUC comparison. The clinical relevance of the malformations is uncertain. No similar malformations or fetal toxicity were observed in offspring from pregnant rats administered intravenous vaborbactam during organogenesis or from late pregnancy and through lactation at a dose equivalent to approximately 1.6 times the MRHD based on body surface area comparison [see Data].

No fetal toxicity or malformations were observed in pregnant rats and cynomolgus monkeys administered intravenous meropenem during organogenesis at doses up to 1.6 and 1.2 times the MRHD based on body surface area comparison, respectively. In rats administered intravenous meropenem in late pregnancy and during the lactation period, there were no adverse effects on offspring at doses equivalent to approximately 1.6 times the MRHD based on body surface area comparison [see Data].

The background risk of major birth defects and miscarriage for the indicated population is unknown. 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

Meropenem

Reproductive studies have been performed with meropenem in rats at doses of up to 1000 mg/kg/day and in cynomolgus monkeys at doses of up to 360 mg/kg/day (on the basis of body surface area comparisons, approximately 1.6 times and 1.2 times higher, respectively, than the MRHD of 2 grams every 8 hours). These studies revealed no evidence of harm to the fetus due to meropenem, although there were slight changes in fetal body weight at doses of 250 mg/kg/day (equivalent to approximately 0.4 times the MRHD of 2 grams every 8 hours based on body surface area comparison) and above in rats. In a published study1, meropenem administered to pregnant rats from Gestation Day 6 to Gestation Day 17, was associated with mild maternal weight loss at all doses, but did not produce malformations or fetal toxicity. The no-observed-adverse-effect-level (NOAEL) for fetal toxicity in this study was considered to be the high dose of 750 mg/kg/day (equivalent to approximately 1.2 times the MRHD based on body surface area comparison).

In a peri-postnatal study in rats described in the published literature1, intravenous meropenem was administered to dams from Gestation Day 17 until Postpartum Day 21. There were no adverse effects in the dams and no adverse effects in the first generation offspring (including developmental, behavioral, and functional assessments and reproductive parameters) except that female offspring exhibited lowered body weights which continued during gestation and nursing of the second generation offspring. Second generation offspring showed no meropenem-related effects. The NOAEL value was considered to be 1000 mg/kg/day (approximately 1.6 times the MRHD based on body surface area comparisons).

Vaborbactam

In a rat embryo-fetal toxicology study, intravenous administration of vaborbactam during Gestation Days 6-17 showed no evidence of maternal or embryofetal toxicity at doses up to 1000 mg/kg, which is equivalent to approximately 1.6 times the MRHD based on body surface area comparisons. In the rabbit, intravenous administration of vaborbactam during Gestation Days 7–19 at doses up to 1000 mg/kg/day (approximately 5 times the MRHD based on AUC exposure comparison) was not associated with maternal toxicity or fetal weight loss. A low incidence of malformations occurred in the 300 mg/kg/day mid-dose group (two fetuses from different litters with interventricular septal defects, one fetus with a fused right lung lobe and one fetus with a supernumerary lung lobe), and in the 1000 mg/kg/day high-dose group (two fetuses from different litters with supernumerary lobes). The NOAEL was considered to be 100 mg/kg/day which is equivalent to 0.3 times the MRHD based on plasma AUC exposure comparison and 6-times the MRHD based on maximum plasma concentration (Cmax) comparison. The clinical relevance of the malformations is uncertain. Vaborbactam Cmax values may have influenced malformations in the rabbit study, and the recommended 3-hour infusion time for clinical administration of vaborbactam is associated with lower plasma Cmax values than the 30-minute infusions in rabbits.

In a peri-postnatal study in rats, vaborbactam administered intravenously to pregnant dams from Gestation Day 6 to Lactation Day 20 caused no adverse effects on the dams, or in first and second generation offspring. The NOAEL was considered to be 1000 mg/kg/day (equivalent to approximately 1.6 times the MRHD based on body surface area comparison).