Pharmacokinetics of Certolizumab Pegol in Pregnancy: Results from the Open-Label CHERISH Study.

Introduction
Control of chronic inflammatory diseases (CIDs) during pregnancy is essential for maternal and foetal health; however, the impact of pregnancy on the pharmacokinetics (PK) of CID therapies is unknown. This study investigated the impact of pregnancy on the PK of certolizumab pegol (CZP), a tumour necrosis factor inhibitor (TNFi), in women with CIDs.Methods
CHERISH (NCT04163016) was a multicentre, longitudinal, open-label phase 1B study evaluating the impact of pregnancy on the PK of CZP in women with CIDs. Pregnant participants on a stable CZP regimen were enrolled at ≤ 10 weeks of gestation. The primary variable was pre-dose and post-dose plasma CZP concentrations throughout pregnancy and postpartum in patients who received ≥ 1 dose. Treatment-emergent adverse events (TEAEs) were recorded.Results
Of 21 enrolled participants (CZP 200 mg every 2 weeks [Q2W], n = 15; CZP 400 mg Q2W, n = 1; CZP 400 mg Q4W, n = 5), 16 completed the study. Relative to postpartum, pre-dose plasma CZP concentrations were modestly reduced across trimesters 1-3, with no clear pattern in post-dose concentrations. TEAEs occurred in 81.0% of participants, with 'infections and infestations' being most common; only 1 (4.8%) was considered treatment related. Five participants (23.8%) experienced serious TEAEs; none were considered treatment-related. One serious TEAE of foetal death in a high-risk twin pregnancy, one spontaneous abortion was reported in an enrolled participant before their first dose of CZP in the study, and no infant illnesses were reported.Conclusions
CZP plasma concentrations were modestly lower during pregnancy versus postpartum, were consistent across trimesters, and were within the range observed in studies of non-pregnant individuals with CIDs. Safety was consistent with the established profile of CZP and the patient population. Findings support maintenance of CZP dosing regimens during pregnancy.Trial Registration
ClinicialTrials.gov identifier: NCT04163016.