8.1Pregnancy Risk Summary
Published observational studies on PIVYA use during the first trimester do not indicate an increased risk of major birth defects ( see Data ). There are limited studies on PIVYA use during pregnancy that evaluate the risk of miscarriage and other adverse maternal or fetal outcomes. These studies have methodological limitations hindering interpretation. No dose adjustment is required in pregnant women (see Clinical Considerations) .
Developmental toxicity studies with pivmecillinam or mecillinam administered during organogenesis to rats and mice showed no evidence of embryo-fetal toxicity, including drug-induced fetal malformations, at doses approximately 3.4 or 7.9 times (rats) or 5.1 or 3.9 times (mice) higher than given to patients receiving the maximum recommended daily dose. Evidence of slight fetotoxicity (reduced ossification) was seen in offspring of rats that were given pivmecillinam during organogenesis at a dose approximately 10.2-fold higher than the maximum recommended daily human dose (see Data) .
The background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background 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% to 4% and 15% to 20%, respectively. Clinical Considerations Interference with Newborn Screening Test Treatment of a pregnant individual with PIVYA prior to delivery may cause a false positive test for isovaleric acidemia in the newborn as part of newborn screening [see Warnings and Precautions ( 5.7 ) and Drug Interactions ( 7.3 )].
Dose Adjustments During Pregnancy and the Postpartum Period No dosage adjustment is recommended for pregnant females (see Data) . Data Human data Two cohort studies in 42,223 pregnant women who were exposed to PIVYA during the first trimester did not observe an increased risk of major birth defects when compared to 50,099 pregnant women exposed to other antibacterial drugs. These two studies were limited by potential exposure misclassification.
No clinically significant differences in mecillinam C max and AUC were observed in pregnant adult women (10 to 32 weeks gestation) administered PIVYA 185 mg orally in a published study. Animal data Pivmecillinam administered during the period of organogenesis (gestation days 6-15) had no adverse effects on embryofetal development in rats or mice at oral doses up to 194 mg/kg/day in rats and 582 mg/kg/day in mice. These doses are approximately 3.4-fold and 5.1-fold higher than the maximum recommended daily human dose based on body surface area, respectively.
There was a skeletal variation (reduced ossification of sternebrae, possibly indicating slight fetotoxicity) in offspring of rats treated at 582 mg/kg/day (approximately 10.2-fold higher than the maximum recommended daily human dose based on body surface area). Mecillinam did not cause adverse effects on embryofetal development in rats and mice when administered by subcutaneous injection at doses up to 450 mg/kg/day (approximately 7.9-fold and 3.9-fold higher than the maximum recommended daily human dose based on body surface area, respectively).
In pre- and postnatal studies in rats where maternal animals were dosed beginning during gestation (Day 15) and continuing throughout the weaning period, neither pivmecillinam nor mecillinam had adverse effects on the maternal animals or on the survival and development of the offspring. Pivmecillinam was given orally at doses up to 582 mg/kg/day and mecillinam was given subcutaneously at doses up to 450 mg/kg/day (approximately 10.2-fold and 7.9-fold higher than the maximum recommended daily human dose of PIVYA, based on body surface area, respectively).
