Certolizumab pegol to prevent adverse pregnancy outcomes in patients with antiphospholipid syndrome and lupus anticoagulant (IMPACT): results of a prospective, single-arm, open-label, phase 2 trial.

Objectives: The aim of this study was to evaluate whether certolizumab pegol, a tumour necrosis factor α inhibitor with little or no transport across the placenta, added to standard treatment with low molecular weight heparin plus low dose aspirin, reduces rates of adverse pregnancy outcome (APO) in high-risk pregnancies with antiphospholipid syndrome (APS).

Methods: We assessed treatment with certolizumab in pregnant patients with APS and lupus anticoagulant, administered gestational weeks 8 through 28, in addition to standard treatment. The primary APO was a composite of fetal death ≥10 weeks' gestation or pre-eclampsia with severe features or placental insufficiency requiring delivery <34 weeks' gestation. Target sample size was 45 with expected APO rate of 20% with certolizumab versus 40% in historical controls from a prospectively observed population of similarly managed APS pregnancies.

Results: Fifty-one patients were enrolled, and 9 had primary APO (17.6%; 95% CI, 8.4%-30.9%). Excluding 6 patients who had a pregnancy loss <10 weeks' gestation or fetal loss due to genetic abnormalities, primary APO occurred in 9 of the 45 patients (20%; 95% CI, 9.6%-34.6%), meeting predetermined criteria for efficacy of certolizumab and significantly lower than rates in historical controls. Median gestational age at delivery in certolizumab-treated patients was 36.5 weeks and was after 30 weeks in those who met the primary outcome of pre-eclampsia. Neonatal survival to hospital discharge was 93%. There were no serious infections and no new cases or severe flares of lupus.

Conclusions: Certolizumab appears effective in preventing placenta-mediated adverse outcomes in high-risk patients with APS.