Belimumab Pregnancy and Breastfeeding Warnings

Brand names: Benlysta

Medically reviewed by Drugs.com. Last updated on Apr 5, 2024.

Belimumab Pregnancy Warnings

This drug should not be used during pregnancy unless clearly needed and the benefit outweighs the risk to the fetus.

AU TGA pregnancy category: C
US FDA pregnancy category: Not assigned

Risk summary: Insufficient data available on use of this drug in pregnant women to inform a drug-related risk. Based on animal data and the mechanism of action of this drug, the immune system in infants of treated mothers may be adversely affected; based on available data, it is unknown if immune effects (if identified) are reversible.

Comments:
-A pregnancy exposure registry is available.
-After benefit/risk has been assessed, if prevention of pregnancy is warranted, patients of childbearing potential should use effective contraception during therapy and for at least 4 months after the last dose; according to some authorities, effective contraception must be used during this time.

Animal studies have failed to reveal evidence of fetal harm. Pregnant cynomolgus monkeys were administered IV doses up to 150 mg/kg every 2 weeks from confirmation of pregnancy (Gestation Days [GD] 20 to 22), throughout organogenesis, and continuing to either scheduled cesarean section (GD 150 [late third trimester]) or day of parturition; no evidence of maternal toxicity, effects on embryofetal and infant survival, or structural abnormalities was observed at exposure about 9 times the maximum recommended human dose (MRHD) of 10 mg/kg IV or 20 times the MRHD of 200 mg subcutaneously (on an AUC basis). Drug-related findings in mothers and in fetuses and/or infants included reduced immature and mature B-cell counts; additional findings in fetuses and/or infants included reduced density of lymphoid tissue B-lymphocytes in the spleen and lymph nodes, reduced spleen weights, increased immunoglobulin G (IgG) titers, and reduced 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. This drug crossed the placenta; it was detected in fetal cord blood and amniotic fluid on GD 150. There are no controlled data in human pregnancy.

To monitor the outcomes of pregnant women exposed to this drug, a pregnancy registry has been established. Health care professionals are encouraged to refer patients and pregnant women are encouraged to enroll themselves by visiting https://mothertobaby.org/ongoing-study/benlysta-belimumab/.

Clinical Considerations:
-Disease-associated maternal and/or embryofetal risk: Pregnant women with systemic lupus erythematosus are at increased risk of adverse pregnancy outcomes (including worsening of underlying disease, premature birth, miscarriage, intrauterine growth restriction). Maternal lupus nephritis increases the risk of hypertension and preeclampsia/eclampsia. Transfer of maternal autoantibodies across the placenta may cause adverse neonatal outcomes (including neonatal lupus, 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/benefits should be considered before administration of live or live-attenuated vaccines to infants exposed to this drug in utero. Infants of treated mothers should be monitored for B-cell reduction and other immune dysfunction.

AU TGA pregnancy category C: Drugs which, owing to their pharmacological effects, have caused or may be suspected of causing, harmful effects on the human fetus or neonate without causing malformations. These effects may be reversible. Accompanying texts should be consulted for further details.

US FDA pregnancy category Not Assigned: The US FDA has amended the pregnancy labeling rule for prescription drug products to require labeling that includes a summary of risk, a discussion of the data supporting that summary, and relevant information to help health care providers make prescribing decisions and counsel women about the use of drugs during pregnancy. Pregnancy categories A, B, C, D, and X are being phased out.

See references

Belimumab Breastfeeding Warnings

Until more data are available, caution is recommended, particularly while breastfeeding newborn or preterm infants; use is considered acceptable according to some experts.
-According to some authorities: A decision should be made to discontinue breastfeeding or discontinue the drug, taking into account the importance of the drug to the mother and the benefit of breastfeeding for the child.

Excreted into human milk: Yes

Comments:
-Developmental and health benefits of breastfeeding should be considered as well as the mother's clinical need for this drug.
-The effects in the nursing infant are unknown; potential adverse effects in the breastfed child due to this drug or the mother's underlying condition should be considered.
-Maternal immunoglobulin G (IgG) is present in human milk.
-The effects of local gastrointestinal exposure and limited systemic exposure to this drug in the nursing infant are unknown.
-According to some experts, waiting for at least 2 weeks postpartum to resume therapy may minimize transfer to the infant.

Preliminary information and a predictive model indicate that levels of this drug in milk are very low. It is also likely to be partially destroyed in the infant's gastrointestinal tract; absorption by the infant is probably minimal. If this drug is required by the mother, it is not a reason to discontinue breastfeeding.

After IV administration in 1 woman (520 mg [10 mg/kg] every 2 weeks for 2 doses, then 520 mg monthly), milk drug levels were 0.12 mg/L at 2 weeks after the first dose and before the second dose, 0.17 mg/L the following day, and 0.12 mg/L at 7 weeks after the second dose. After 200 mg subcutaneously every 2 weeks in 2 lactating women, milk levels were highest at about 3 days after dosing (about 75 and 125 mcg/L); at 7 days after dosing, milk levels were relatively stable in the first woman and decreased to about 90 mcg/L in the other woman.

A woman received monthly infusions of this drug (dose not specified) during pregnancy and continued postpartum, starting at 2 weeks postpartum. She breastfed her infant (extent not specified); no infant effects were stated.

See references

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer