Summary of Use during Lactation

Preliminary information indicates that belimumab levels in milk are very low. It is also likely to be partially destroyed in the infant's gastrointestinal tract and absorption by the infant is probably minimal.[1] If belimumab is required by the mother, it is not a reason to discontinue breastfeeding. Some professional guidelines consider belimumab to be acceptable during breastfeeding.[2,3] Until more data become available, belimumab should be used with caution during breastfeeding, especially while nursing a newborn or preterm infant. Waiting for at least 2 weeks postpartum to resume therapy may minimize transfer to the infant.[4]

Drug Levels

Maternal Levels. A postpartum woman with mixed connective tissue disease was started on intravenous belimumab 520 mg (10 mg/kg) every 2 weeks for 2 doses, then 520 mg monthly as well as hydroxychloroquine 200 to 400 mg daily. Belimumab milk concentrations were 0.12 mg/L at 2 weeks after the first dose and prior to the second dose, 0.17 mg/L on the following day, and 0.12 mg/L at 7 weeks after the second dose.[5]

Two lactating women who were receiving belimumab 200 mg subcutaneously every 2 weeks donated milk samples postpartum at starting at 3 to 4 days postpartum. Milk concentrations were highest at about 3 days after the dose at about 75 mcg/L in one woman and about 125 mcg/L in the other. At 7 days after the dose, milk levels remained relatively constant in the first woman and decreased to about 90 mcg/L in the second.[6]

Infant Levels. Relevant published information was not found as of the revision date.

Effects in Breastfed Infants

A woman with systemic lupus erythematosus was taking belimumab (dose not stated) for 1 year when she became pregnant. She received monthly belimumab infusions during pregnancy and continued postpartum, starting at 2 weeks postpartum. She breastfed her infant (extent not stated). No infant effects were mentioned.[7]

Effects on Lactation and Breastmilk

Relevant published information was not found as of the revision date.

References

1.

Sammaritano LR, Bermas BL, Chakravarty EE, et al. 2020 American College of Rheumatology Guideline for the Management of Reproductive Health in Rheumatic and Musculoskeletal Diseases. Arthritis Rheumatol 2020;72:529-56. [PubMed: 32090480]

2.

Götestam Skorpen C, Hoeltzenbein M, Tincani A, et al. The EULAR points to consider for use of antirheumatic drugs before pregnancy, and during pregnancy and lactation. Ann Rheum Dis 2016;75:795-810. [PubMed: 26888948]

3.

Russell MD, Dey M, Flint J, et al. British Society for Rheumatology guideline on prescribing drugs in pregnancy and breastfeeding: Immunomodulatory anti-rheumatic drugs and corticosteroids. Rheumatology (Oxford) 2023;62:e48-e88. [PMC free article: PMC10070073] [PubMed: 36318966]

4.

Krysko KM, Dobson R, Alroughani R, et al. Family planning considerations in people with multiple sclerosis. Lancet Neurol 2023;22:350-66. [PubMed: 36931808]

5.

Saito J, Yakuwa N, Ishizuka T, et al. Belimumab concentrations in maternal serum and breast milk during breastfeeding and the safety assessment of the infant: A case study. Breastfeed Med 2020;15:475-7. doi: 10.1111/bcp.15876 [PMC free article: PMC7374635] [PubMed: 32326740] [CrossRef]

6.

Saito J, Yakuwa N, Hosokawa Y, et al. Establishment of a measurement system to evaluate breast milk transfer of biological agents using dry filter paper: a multi-institutional study. Br J Clin Pharmacol 2023. [PubMed: 37548054]

7.

Danve A, Perry L, Deodhar A. Use of belimumab throughout pregnancy to treat active systemic lupus erythematosus: A case report. Semin Arthritis Rheum 2014;44:195-7. [PubMed: 25005336]

Substance Name

Belimumab

CAS Registry Number

356547-88-1

Drug Class

Breast Feeding

Lactation

Milk, Human

Antibodies, Monoclonal