Pregnancy Exposure Registry

There is a pregnancy exposure registry that evaluates pregnancy outcomes in women with lupus exposed to BENLYSTA during pregnancy. Healthcare professionals are encouraged to refer patients and pregnant women are encouraged to enroll themselves by calling 1-877-311-8972 or visiting https://mothertobaby.org/ongoing-study/benlysta-belimumab/.

Risk Summary

Available data on use of BENLYSTA in pregnant women, from observational studies, published case reports, and postmarketing surveillance, are insufficient to determine whether there is a drug-associated risk for major birth defects or miscarriage. There are risks to the mother and fetus associated with SLE (see Clinical Considerations). Monoclonal antibodies, such as belimumab, are actively transported across the placenta during the third trimester of pregnancy and may affect immune response in the in utero-exposed infant (see Clinical Considerations). In an animal combined embryo-fetal and pre- and post-natal development study with monkeys that received belimumab by intravenous administration, there was no evidence of fetal harm with exposures approximately 9 times (based on intravenous administration) and 20 times (based on subcutaneous administration) the exposure at the maximum recommended human dose (MRHD). Belimumab-related findings in monkey fetuses and/or infants included reductions of B-cell counts, reductions in the density of lymphoid tissue B-lymphocytes in the spleen and lymph nodes, and altered IgG and IgM titers. The no-adverse-effect-level (NOAEL) was not identified for these findings; however, they were reversible within 3 to 12 months after the drug was discontinued (see Data). Based on animal data and the mechanism of action of belimumab, the immune system in infants of treated mothers may be adversely affected. It is unknown, based on available data, whether immune effects, if identified, are reversible [see Clinical Pharmacology (12.1)].

The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively.

Clinical Considerations

Disease-Associated Maternal and/or Embryo/Fetal Risk: Pregnant women with SLE are at increased risk of adverse pregnancy outcomes, including worsening of the underlying disease, premature birth, miscarriage, and intrauterine growth restriction. Maternal lupus nephritis increases the risk of hypertension and preeclampsia/eclampsia. Passage of maternal autoantibodies across the placenta may result in adverse neonatal outcomes, including neonatal lupus and congenital heart block.

Fetal/Neonatal Adverse Reactions: Monoclonal antibodies are increasingly transported across the placenta as pregnancy progresses, with the largest amount transferred during the third trimester. Risks and benefits should be considered prior to administering live or live-attenuated vaccines to infants exposed to BENLYSTA in utero. Monitor an infant of a treated mother for B-cell reduction and other immune dysfunction [see Warnings and Precautions (5.5)].

Data

Animal Data: In a combined embryo-fetal and pre- and post-natal development study, pregnant cynomolgus monkeys received belimumab at intravenous doses of 0, 5, or 150 mg/kg every 2 weeks from confirmation of pregnancy at Gestation Days (GD) 20 to 22, throughout the period of organogenesis (up to approximately GD 50), and continuing to either the day of scheduled cesarean section (GD 150 [late third trimester]) or the day of parturition. There was no evidence of maternal toxicity, effects on embryofetal and infant survival, or structural abnormalities at exposure approximately 9 times the MRHD of 10 mg/kg intravenously or 20 times the MRHD of 200 mg subcutaneously (on an area under the curve [AUC] basis with maternal animal intravenous doses up to 150 mg/kg). Belimumab-related findings in mothers included reductions of immature and mature B-cell counts and in fetuses and/or infants included reductions of immature and mature B-cell counts, reductions in the density of lymphoid tissue B-lymphocytes in the spleen and lymph nodes, reduced spleen weights, increased IgG titers, and reduced IgM titers. B-cell counts in infant monkeys exposed to belimumab in utero recovered by 3 months of age and in mothers after 1 year. Immunoglobulin G (IgG) and IgM levels in infant monkeys recovered by 6 months of age and the reductions in B-lymphocytes in the lymph nodes and spleen were reversed by 1 year of age. Belimumab crossed the placenta, as it was detected in fetal cord blood and amniotic fluid on GD 150.