Risk Summary  
  
Ibandronate sodium is not indicated for use in women of reproductive potential. There are no data with ibandronate sodium use in pregnant women to inform any drug-associated risks.  
  
In reproductive toxicity studies in the rat, ibandronate sodium caused post-implantation loss and obstruction of labor with maternal and fetal periparturient mortality at greater than or equal to 3 times human exposure at the recommended 2.5 mg daily oral dose, or at greater than or equal to 1 times human exposure at the recommended 150 mg once-monthly oral dose. In pregnant rats, kidney developmental toxicity occurred in offspring at greater than or equal to 30 times the daily 2.5 mg human dose or at greater than or equal to 9 times the once-monthly 150 mg human dose. In rat reproductive studies, impaired pup neuromuscular development was observed at 45 times the daily 2.5 mg dose and 13 times the once-monthly 150 mg dose. In reproductive studies in the rabbit, ibandronate sodium caused maternal mortality at greater than or equal to 8 times the daily 2.5 mg dose and greater than or equal to 4 times the once-monthly 150 mg dose (see Data).  


Data  


Animal Data

In female rats given ibandronate at oral doses greater than or equal to 3 times human exposure at the recommended daily oral dose of 2.5 mg or greater than or equal to 1 times human exposure at the recommended once-monthly oral dose of 150 mg beginning 14 days before mating and continuing through lactation, maternal deaths were observed at the time of delivery in all dose groups. Perinatal pup loss in dams given doses producing 45 times human exposure at the recommended daily dose and 13 times human exposure at the recommended once-monthly dose was likely related to maternal dystocia. Calcium supplementation did not completely prevent dystocia and periparturient mortality in any of the treated groups at greater than or equal to 16 times the recommended daily dose and greater than or equal to 4.6 times the recommended once-monthly dose. A low incidence of postimplantation loss was observed in rats treated from 14 days before mating throughout lactation or during gestation, only at doses causing maternal dystocia and periparturient mortality. In pregnant rats dosed orally from gestation day 17 through lactation day 21 (following closure of the hard palate through weaning), maternal toxicity, including dystocia and mortality, fetal perinatal and postnatal mortality, were observed at doses equivalent to human exposure at the recommended daily dose and greater than or equal to 4 times the recommended once-monthly dose. Periparturient mortality has also been observed with other bisphosphonates and appears to be a class effect related to inhibition of skeletal calcium mobilization resulting in hypocalcemia and dystocia.

Exposure of pregnant rats during the period of organogenesis resulted in an increased fetal incidence of RPU (renal pelvis ureter) syndrome at oral doses producing 30 times human exposure at the recommended daily oral dose of 2.5 mg and greater than or equal to 9 times human exposure at the recommended once-monthly oral dose of 150 mg. Impaired pup neuromuscular development (cliff avoidance test) was observed at 45 times human exposure at the daily dose and 13 times the once-monthly dose.

In pregnant rabbits treated orally with ibandronate during gestation at doses greater than or equal to 8 times the recommended human daily oral dose of 2.5 mg and greater than or equal to 4 times the recommended human once-monthly oral dose of 150 mg, dose-related maternal mortality was observed in all treatment groups. The deaths occurred prior to parturition and were associated with lung edema and hemorrhage. No significant fetal anomalies were observed. 

Exposure multiples for the rat studies were calculated for the recommended daily oral dose of 2.5 mg or once-monthly dose of 150 mg based on area under the curve (AUC) comparison. Exposure multiples for the rabbit study were calculated for the recommended human daily oral dose of 2.5 mg or once-monthly dose of 150 mg based on dose/body surface area comparison. Doses used in pregnant animals were 1, 4, 5, 6, 16, 10, 20, 30, 60 or 100 mg/kg/day in rats, and 1, 4 or 20 mg/kg/day in rabbits.