Summary of Use during Lactation

Preliminary information and a predictive model indicate that belimumab levels in milk are very low.[1] It is also likely to be partially destroyed in the infant's gastrointestinal tract and absorption by the infant is probably minimal.[2,3] 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.[4,5] 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.[6]

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.[7]

Two lactating women with systemic lupus erythematosus 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.[8]

A woman with systemic lupus erythematosus was started on belimumab 200 mg subcutaneously every two weeks and discontinued breastfeeding at 3 months postpartum. She continued to pump milk to avoid engorgement. Two milk samples were analyzed for belimumab. On day 14 after 2 doses of the drug, an evening milk sample contained 0.264 mg/L of belimumab and a second sample taken on day 28 before the fifth dose contained 0.885 mg/L.[9]

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.[10]

Effects on Lactation and Breastmilk

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

References

1.

Stratigakis A, Paty D, Zou P, et al. A regression approach for assessing large molecular drug concentration in breast milk. Reprod Breed 2023;3:199-207. doi:10.1016/j.repbre.2023.10.003 [CrossRef]

2.

Anderson PO. Monoclonal antibodies during breastfeeding. Breastfeed Med 2021;16:591-3. [PubMed: 33956488]

3.

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]

4.

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]

5.

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]

6.

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

7.

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. [PMC free article: PMC7374635] [PubMed: 32326740]

8.

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 2024;90:146–57. [PubMed: 37548054]

9.

Blomjous BS, de Boer MA, van Weissenbruch MM, et al. Concentrations of subcutaneously administered belimumab in human breast milk of a woman with systemic lupus erythematosus: a case report. Lupus Sci Med 2024;11:e001167. [PMC free article: PMC10953294] [PubMed: 38499356]

10.

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