AB1504 BIOSIMILARS IN BLOOM: MATERNAL AND PERINATAL OUTCOMES IN PREGNANT WOMEN WITH RHEUMATIC DISEASES TREATED WITH BIOSIMILAR TNF INHIBITORS
Authors: A. Teodósio Chícharo, A. R. Lopes, S. Barreira, L. Pinto, A. R. Cruz-Machado, S. Capela
Journal: Annals of the Rheumatic Diseases (2024)

<h3>Background:</h3> Biosimilar drugs are agents with highly similar characteristics to original biologic DMARDs. There is scarce data about their use in pregnancy, and for this reason they are not addressed in the latest EULAR, ACR or British Society guidelines on reproductive health for rheumatic patients. <h3>Objectives:</h3> To describe maternal and perinatal outcomes in women using biosimilar TNFi during conception and gestation. <h3>Methods:</h3> Single-centre observational retrospective study of pregnant rheumatic woman exposed to biosimilar TNFi. <h3>Results:</h3> Five pregnancies in three caucasian women were included. Rheumatic diagnoses were rheumatoid arthritis (RA), axial spondyloarthritis (axSpA) and psoriatic arthritis (PsA). Table 1 summarizes maternal and perinatal outcomes and relevant clinical data. At the time of conception, all patients were in remission under Bs therapy: one on Bs infliximab (IFXb) and two on Bs etanercept (ETAb). The first case refers to a nulliparous woman aged 35 diagnosed with axSpA. After conception, IFXb 5 mg/kg every 9 weeks was maintained up to the 18 week of gestation (WG). No adverse pregnancy outcomes (APO) or disease activity flares were noticed. Three years later, during a subsequent pregnancy, she remained on IFXb monotherapy at the same dosing scheme. At 18WG, she experienced a sacroiliitis flare, resolved after joint injection with methylprednisolone. IFXb was last administered at the 24WG, and the remaining pregnancy was uneventful. The second patient was a 30-year-old woman diagnosed with RA treated with ETAb 50mg weekly, sulfasalazine 1g/day and prednisolone (≤5mg/day). After conception, ETAb dosage was adjusted to 50mg every other week until 30WG due to sustained remission. No flares or APO were recorded. This woman had experienced a miscarriage at 8WG the year before, while on remission and under the above-mentioned treatment. The last case involves a 32-year-old woman with PsA under ETAb 50mg weekly in monotherapy. In this patient, ETAb was continued up to the 26WG, when it was stopped due to a mild urinary tract infection, successfully treated with a course of antibiotics. Although the arthritis remained under control, psoriasis relapsed after discontinuing the Bs, requiring the use of topical emollients. All women gave birth to healthy term babies. One neonatal infection (<i>E.coli</i> urosepsis) required intravenous antibiotics and resolved without sequelae. All women decided to breastfeed and resumed biosimilar therapy postpartum. <h3>Conclusion:</h3> No safety or efficacy issues arose from the use of IFXb or ETAb during conception, pregnancy or breastfeeding. Our data are reassuring: patients under biosimilar TNFi should continue their usual therapy to reduce the risk of flares and of APO. REFERENCES: NIL. <h3>Acknowledgements:</h3> <b>NIL.</b> <h3>Disclosure of Interests:</h3> <b>None declared.</b>