Background SLE is an autoimmune disease typically affecting women of childbearing age that can be associated with significant maternal and fetal morbidity. Belimumab is a biologic approved as adjunctive therapy for SLE. Although pregnant women were excluded from belimumab clinical trials and treatment was discontinued if a pregnancy occurred, pregnancy outcomes were collected when a pregnancy was identified.

Objectives To describe pregnancy outcomes of women who conceived while participating in belimumab phase 2-4 clinical trial studies.

Methods Cumulative pregnancy outcome data with autoantibody status (when available) were collected from women who conceived while participating in belimumab SLE phase 2-4 clinical trials.

Results As of 08 March 2013, 66 pregnancies with known outcomes in subjects who received belimumab and 6 who received placebo had been reported in the IV and SC SLE studies (Table). A lower frequency of fetal loss was noted in subjects treated with belimumab (27%; 18 of 66) compared to the placebo group (50%; 3 of 6). Live births were noted in 33 of 66 pregnancies (50%) in the belimumab group, 3 of which were associated with congenital anomalies (1 case of Dandy Walker syndrome, 1 case of bilateral enlarged kidneys in a pregnancy also exposed to a known teratogenic drug, and an unbalanced translocation involving chromosomes 11 and 13 that was linked to the mother). In the group receiving belimumab, anticardiolipin antibodies were present at baseline in 21% (7 of 33) of subjects who had live births and in 44% (8 of 18) of subjects with fetal loss.

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Conclusions Total fetal loss in belimumab-treated subjects was similar to background estimates in SLE patients (∼25%), although data remain limited. Valuable clinical information can be obtained through the Belimumab Pregnancy Registry (BPR), an international, prospective cohort study with voluntary participation. The BPR will add to current clinical experience with belimumab and assist clinicians and patients regarding potential risks and benefits of treating SLE patients who are contemplating pregnancy or are pregnant. GSK1550188; eTrack Study #201182

References

1. Andrade R, Sanchez ML, Alarcon GS, et al. Adverse pregnancy outcomes in women with systemic lupus erythematosus from a multiethnic US cohort: LUMINA (LU1). Clin Exp Rheumatol. 2008;26:268-74.

2. Clowse ME, Magder LS, Witter F et al. The impact of increased lupus activity on obstetric outcomes. Arthritis Rheum. 2005;52:514-21.

3. Rahman P, Gladman DD, Urowitz MB. Clinical predictors of fetal outcome in systemic lupus erythematosus. J Rheumatol. 1998; 25.8:1526-30.

Disclosure of Interest M. Powell Shareholder of: GlaxoSmithKline, Employee of: GlaxoSmithKline, D. Hill Shareholder of: GlaxoSmithKline, Employee of: GlaxoSmithKline, A. Eudy Employee of: GlaxoSmithKline, H. Landy Consultant for: GlaxoSmithKline, M. Petri Consultant for: GlaxoSmithKline

DOI 10.1136/annrheumdis-2014-eular.4484