Intravenous immunoglobulin treatment for obstetric antiphospholipid syndrome refractory to conventional therapy: A single-arm, open-labelled multicentre clinical trial.

Objectives: The objective of the study was to compare the efficacy of intravenous immunoglobulin (IVIG) therapy for obstetric antiphospholipid syndrome (APS) refractory to conventional treatment.

Methods: We conducted a single-arm, open-label multicentre clinical intervention trial. The enrolled criteria were patients with refractory APS who had a history of still or premature birth before 30 weeks of gestational age, even though they had been treated with conventional treatment, i.e. heparin and low-dose aspirin. After confirming the foetal heartbeats, a single course of IVIG (0.4 g/kg body weight daily for 5 days) was added to conventional treatment. The primary outcome was a live birth ratio of >30 weeks of gestational period, and the secondary outcome included improving pregnancy outcomes compared to previous pregnancy.

Results: Twenty-five per cent of patients (2 of 8 cases) achieved a live birth after the 30th week of pregnancy by IVIG-only add-on treatment, which is the same prevalence as the historical control. However, by adding other second-line therapy to IVIG and conventional treatment, further three patients (37.5%) achieved improvements in pregnancy outcome compared to previous treatments. In total, five patients (62.5%) were able to achieve preferable pregnancy outcomes through combination treatment including IVIG.

Conclusions: This clinical trial could not demonstrate the efficacy of IVIG-only add-on therapy at improving the pregnancy outcomes of patients with obstetric APS refractory to conventional treatment. However, the combination of IVIG with rituximab or statins adding to conventional treatment improved pregnancy outcomes and resulted in more live births. Further studies are needed to investigate the efficacy of multi-targeted therapy to treat obstetric refractory APS.