Pregnancy outcomes following periconceptional or gestational exposure to ustekinumab: Review of cases reported to the manufacturer's global safety database

Background: Ustekinumab, a human immunoglobulin G1 monoclonal antibody that binds to and inhibits interleukin (IL)-12/IL-23, is indicated for multiple immune-mediated diseases. Ustekinumab is actively transported across the placenta and theoretically could impact pregnancy outcomes. Limited data on pregnancy outcomes with ustekinumab exposure are available. Aim: To assess pregnancy outcomes in patients exposed to ustekinumab during pregnancy. Methods: Cumulative data on medically confirmed ustekinumab-exposed pregnancies from the manufacturer's Global Safety Database were summarised. Descriptive data for pregnancy outcomes were presented overall and by patient subgroups. Results: As of 31 August 2020, 408 medically confirmed, prospective, maternal ustekinumab-exposed pregnancies with reported outcomes were identified. The mean maternal age was 31 years. Of the 420 pregnancy outcomes (including 4 sets of twins),^a,b 340 (81%) were live births, 51 (12.1%) spontaneous abortions, 25 (6%) elective/induced abortions, 3 (0.7%) stillbirths and 1 (0.2%) ongoing pregnancy with foetal congenital anomaly (CA). Among 340 live births, 33 (9.7%) were born pre-term. The rate of major CAs was similar by indication (Crohn's disease vs psoriasis), ustekinumab dose (45 mg vs 90 mg) and timing and duration of maternal exposure to ustekinumab. Prospective outcomes of pregnancies with paternal periconceptional ustekinumab exposure (n = 87) included 92% live births (1.2% major CA), 5.7% spontaneous abortions and 2.3% elective/induced abortions. Conclusions: Rates of adverse pregnancy outcomes or CAs with ustekinumab exposure were consistent with rates reported for the US general population and do not suggest a higher risk associated with maternal or paternal exposure to ustekinumab.