Ustekinumab Exposure in Pregnant Women from Inflammatory Bowel Disease Clinical Trials: Pregnancy Outcomes Through Up to 5 Years in Crohn's Disease and 2 Years in Ulcerative Colitis

Background: While no adverse developmental outcomes were observed in preclinical animal studies, limited data exist regarding effects of ustekinumab on human pregnancies. Previously, no data have been reported for women treated with ustekinumab in inflammatory bowel disease (IBD) clinical trials and corresponding pregnancy outcomes. Here, we present pregnancy outcomes from IBD clinical trials, incorporating 5 years of treatment in Crohn's disease (CD) and 2 in ulcerative colitis (UC). Methods: All patients in the clinical trials agreed to use adequate birth control and were discontinued from treatment upon pregnancy confirmation. Nonetheless, 39 pregnancies occurred with maternal ustekinumab exposure from 4 CD and 1 UC study. Maternal and neonatal outcomes and data are presented with summary statistics, where available. Results: Of 1289 women who received ≥1 dose of ustekinumab, 39 maternal pregnancies with outcomes were reported (pregnancy cohort). Median maternal age was 28.0 years and median duration of ustekinumab treatment before pregnancy was 63.7 weeks with the last dose of ustekinumab administered prior to or during the first trimester (terminal half-life of ~3 weeks). Outcomes for the 39 pregnancies were: 26 live births (all normal newborns), 8 spontaneous abortions, and 5 elective abortions. No congenital anomalies were reported among normal newborns and no safety signals emerged with neonatal outcomes. Conclusions: Based on this series of 39 pregnancies with outcomes from IBD clinical trials, mothers treated with ustekinumab (limited to up to the first trimester) did not demonstrate a risk of negative outcomes. More data are needed to characterize the safety profile of ustekinumab use during pregnancy.