PMS-Entecavir Use In Pregnancy & Lactation

Pregnancy: Pregnancy Category C: There are no adequate and well-controlled studies of pms-ENTECAVIR in pregnant women. When pregnant rats and rabbits received entecavir at 28 and 212 times the human exposure at the highest human dose, there were no signs of embryofetal toxicity. Because animal reproduction studies are not always predictive of human response, pms-ENTECAVIR should be used during pregnancy only if clearly needed and after careful consideration of the risks and benefits.
Developmental toxicity studies were performed in rats and rabbits. There were no signs of embryofetal or maternal toxicity when pregnant animals received oral entecavir at approximately 28 (rat) and 212 (rabbit) times the human exposure achieved at the highest recommended human dose of 1 mg/day. In rats, maternal toxicity, embryofetal toxicity (resorptions), lower fetal body weights, tail and vertebral malformations, reduced ossification (vertebrae, sternebrae, and phalanges), and extra lumbar vertebrae and ribs were observed at exposures 3100 times those in humans. In rabbits, embryofetal toxicity (resorptions), reduced ossification (hyoid), and an increased incidence of 13th rib were observed at exposures 883 times those in humans. In a peri-postnatal study, no adverse effects on offspring occurred when rats received oral entecavir at exposures greater than 94 times those in humans.
Labor and Delivery: There are no studies in pregnant women and no data on the effect of pms-ENTECAVIR on transmission of HBV from mother to infant. Therefore, appropriate interventions should be used to prevent neonatal acquisition of HBV.
Nursing Mothers: It is not known whether pms-ENTECAVIR is excreted into human milk; however, entecavir is excreted into the milk of rats. Because many drugs are excreted into human milk and because of the potential for serious adverse reactions in nursing infants from pms-ENTECAVIR , a decision should be made to discontinue nursing or to discontinue pms-ENTECAVIR taking into consideration the importance of continued hepatitis B therapy to the mother and the known benefits of breastfeeding.