(235) Dilemma of Belimumab Therapy (Dis)Continuation During Pregnancy: Results of a Retrospective Study in EudraVigilance

Publication Number: 566

Background: Active systemic lupus erythematosus (SLE) and nephritis due to SLE contribute to poor pregnancy outcomes and higher morbidities and mortalities in the mothers and their foetuses. Corticosteroids, azathioprine, hydroxychloroquine, ciclosporine and tacrolimus are considered safe treatments during pregnancy. However, these treatment options may still not be sufficient in patients poorly responsive to conventional therapies or patients who suffer from nephritis. The only biologic authorized for SLE up to this date, belimumab, is currently not recommended for use during pregnancy due to lack of data.
Pregnant patients, face the dilemma of cessation or continuation of belimumab. If belimumab is stopped there will be a risk of SLE flare and its consequences for mother and foetus. Continuation is also not optimal because the lack of knowledge.

Objectives: To compare the reported foetal outcomes in SLE patients who stopped scheduled belimumab within the first trimester (group A) and who continued scheduled belimumab during the first trimester or thereafter (group B).

Methods: This was a retrospective comparative study. All belimumab-exposed pregnancy-related reports, were extracted from the EudraVigilance (EV) database until March 11th 2021. After case review, repeated cases, uninformative reports, nonmedical elective abortions and foetal chromosomal abnormalities were excluded. Included pregnancies were divided into two groups (group A and B, as described above). Foetal outcomes were divided into live birth or foetal death (due to miscarriage or still birth) and were compared between both groups. Furthermore, neonatal outcomes, such as reporting rates of pre-term birth, low birth weight and major congenital malformations (CMs) were compared.

Results: No statistical difference in foetal death was observed between group A (n=69) and B (n=21) (reporting rates: 46.4% and 52.4%, respectively; p-value>0.05). Reporting rates of major CMs, pre-term birth and low birth weight were higher - though not statistically different- in group A (14.5% vs 9.5%, 43% vs 40% and 24.3% vs 0%, respectively).

Conclusions: Based on our study belimumab continuation during first trimester or thereafter does not result in higher reporting of foetal death. Therefore, continuation might be even preferable if the pregnancy is already exposed to belimumab. Since the analysis is based on spontaneous reports / retrospective data, additional studies are needed to confirm the results.