Filip, R

Abstract Background JAK inhibitors (JAKi) are small molecules that cross the placenta from early pregnancy.1 Evidence on the safety of in utero JAKi exposure remains limited, particularly regarding pregnancy outcomes, infant infections, vaccine responses, and early development.2, 3 Methods We conducted a multicenter retrospective study within the ECCO CONFER network, including pregnant women with inflammatory bowel disease (IBD) exposed to tofacitinib (TOFA), upadacitinib (UPA), or filgotinib (FILGO). Data were collected from 22 centers across 16 countries and included maternal characteristics, disease activity, medication patterns, and pregnancy and infant outcomes. Results Among 55 JAKi exposed pregnancies, 21 (38.2%) were unplanned and 30 (54.6%) had active disease. Nine women (16.4%) initiated JAKi during pregnancy. Overall, 38 (69.1%) received TOFA, 15 (27.3%) UPA, and 2 (3.6%) FILGO; 39 (70.9%) continued treatment throughout pregnancy. JAKi discontinuation in 1st-2nd trimester led to disease activity in 9/16 cases (56.3%). Maternal complication risk was low: no DVT or (pre) eclampsia occurred; three cases of premature rupture of membranes (GA 34–37) and four required hospitalizations due to infection or other complications. A total of 10 abortions occurred - five spontaneous (9.1%) and five induced (9.1%), including three due to concern about JAKi exposure. Among 45 live births, two infants (3.6%) were preterm, four (7.3%) small for gestational age, and two (3.6%) had Apgar <7 at 5 minutes. No congenital abnormalities were reported. Infant follow-up findings are summarized in Table 1. One-third of breastfeeding women continued JAKi postpartum. A high adherence rate to the national immunization schedule was seen. Eight (19.5%) received the live BCG-vaccine within the first 30 days of life. No adverse events followed live or inactivated vaccines, and no malignancies were observed. Conclusion In this global cohort of JAKi-exposed pregnancies in women with IBD, maternal complication rates were low, and no increased risk of adverse outcomes among live births was identified. While disease activity was common, particularly following discontinuation of JAKi, infant outcomes - including development, infection risk, and vaccine response - were reassuring. These findings provide important preliminary safety data to inform decision-making regarding JAKi use in pregnancy, though prospective studies are needed to confirm long-term safety. References: 1.Fein KC, Arral ML, Kim JS, et al. Placental drug transport and fetal exposure during pregnancy is determined by drug molecular size, chemistry, and conformation. J Control Release 2023;361:29–39. 2.Torres J, Chaparro M, Julsgaard M, et al. European Crohn’s and Colitis Guidelines on Sexuality, Fertility, Pregnancy, and Lactation. J Crohns Colitis 2023;17:1–27. 3.Mahadevan U, Seow CH, Barnes EL, et al. Global Consensus Statement on the Management of Pregnancy in Inflammatory Bowel Disease. J Crohns Colitis 2025;epub ahead of print. Conflict of interest: Julsgaard, Mette: No conflict of interest Baunwall, Simon MD: No conflict of interest Seow, Cynthia: No conflict of interest Duricova, Dana: No conflict of interest Kane, Sunanda: No conflict of interest Zacharias, Neha: No conflict of interest Leong, Rupert: No conflict of interest Cremer, Anneline: No conflict of interest Kok, Klaartje: No conflict of interest Kagramanova, Anna Valeryevna: No conflict of interest Pipek, Barbora: No conflict of interest Candido, Kristina: No conflict of interest Cooney, Rachel: No conflict of interest Filip, Rafal: No conflict of interest Kiudelis, Vytautas: No conflict of interest Konečný, Michal: No conflict of interest Paramsothy, Sudarshan: No conflict of interest Pugliese, Daniela: No conflict of interest Oliveira Santana Silva, Genoile: Honoraria - Abbvie, Johnson & Johnson, Ferring, Takeda. Research - Abivax, Takeda, Johnson & Johnson, Roche, Sanofi, Polpharma. Advisory board - Abbvie, Johnson & Johnson, MSD. Savarino, Edoardo Vincenzo: No conflict of interest Smolovic, Brigita: No conflict of interest Vieujean, Sophie: No conflict of interest Wei, Shu Chen: No conflict of interest Mahadevan-Velayos, Uma: No conflict of interest

Abstract Aims SELECTION (NCT02914522) Maintenance evaluated filgotinib (FIL), a preferential JAK1 inhibitor, as maintenance therapy for patients (pts) with moderately to severely active ulcerative colitis (UC) who achieved clinical remission or Mayo Clinic Score (MCS) response after 10 weeks of FIL 200mg QD, FIL 100mg QD or placebo (PBO) induction. Methods Pts randomized to FIL induction were rerandomized 2:1 to their induction FIL dose or PBO; pts randomized to PBO induction continued PBO maintenance. Steroid tapering was mandatory. The primary endpoint was clinical remission at Week 58. Key secondary endpoints and exploratory endpoints were assessed at Week 58. Results 664 pts were treated in the Maintenance Study (n=93, 270, and 301 from induction with PBO, FIL 100mg and FIL 200mg); efficacy analyses included only FIL induction pts. Baseline demographics and disease characteristics were generally balanced across treatment arms; 40% were biologic experienced. Significantly higher proportion of pts on FIL 200mg or FIL 100mg were in clinical remission vs PBO. Significantly higher proportions of pts achieved key secondary endpoints with FIL 200mg vs PBO. More pts on FIL 200 mg or FIL 100mg achieved an MCS response and endoscopic improvement vs PBO. Incidences of adverse events (AEs), serious AEs and discontinuations due to AEs were similar across arms. Serious infection (<2%) and herpes zoster (<1%) were infrequent among FIL-treated patients. There were no venous thromboses, including pulmonary embolism, among FIL-treated pts. Two pts on FIL 200mg died, both AEs leading to death were considered unrelated to FIL. Conclusions FIL 200mg and FIL 100mg were effective as maintenance treatment for pts with moderately to severely active UC who had achieved clinical response to FIL induction treatment. FIL 200 mg met all key secondary endpoints including endoscopic, histologic and 6-month corticosteroid-free remission. FIL was well tolerated in pts with moderate to severely active UC. Funding Agencies None