The Basics
What is Natalizumab?
Used to treat multiple sclerosis and Crohn’s disease.
Brand names for Natalizumab
Tysabri
How Natalizumab is classified
Antibodies – Monoclonal, Anti-Inflammatory Agents
Natalizumab During Pregnancy
Natalizumab pregnancy category
Category CNote that the FDA has deprecated the use of pregnancy categories, so for some medications, this information isn’t available. We still think it’s useful to list historical info, however, given what a common proxy this has been in the past.
What we know about taking Natalizumab while pregnant
There are no adequate data on the developmental risk associated with the use of TYSABRI in pregnant women. In animal studies, administration of natalizumab during pregnancy produced fetal immunologic and hematologic effects in monkeys at doses similar to the human dose and reduced offspring survival in guinea pigs at doses greater than the human dose. These doses were not maternally toxic but produced the expected pharmacological effects in maternal animals . In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2-4% and 15-20%, respectively. The background risk of major birth defects and miscarriage for the indicated population is unknown.
Taking Natalizumab While Breastfeeding
What are recommendations for lactation if you're taking Natalizumab?
Natalizumab is excreted into breastmilk in some, but not all, women. The time of the peak level in breastmilk is variable, but might be as long as 6 months. Because natalizumab is a large protein molecule with a molecular weight of about 149,000, absorption is unlikely because it is probably destroyed in the infant’s gastrointestinal tract. Some experts recommend avoiding breastfeeding with natalizumab, while others do not.[1][2][3] Until more data become available, natalizumab should be used with caution during breastfeeding, especially while nursing a newborn or preterm infant.
Maternal / infant drug levels
Natalizumab is excreted into breastmilk in some, but not all, women. The time of the peak level in breastmilk is variable, but might be as long as 6 months. Because natalizumab is a large protein molecule with a molecular weight of about 149,000, absorption is unlikely because it is probably destroyed in the infant’s gastrointestinal tract. Some experts recommend avoiding breastfeeding with natalizumab, while others do not.[1][2][3] Until more data become available, natalizumab should be used with caution during breastfeeding, especially while nursing a newborn or preterm infant.
Possible effects of Natalizumab on milk supply
Relevant published information was not found as of the revision date.
Possible alternatives to Natalizumab
(Inflammatory Bowel Disease) Budesonide, Infliximab, Mesalamine, Prednisone; (Multiple Sclerosis) Glatiramer, Immune Globulin, Interferon beta.
List of References
Lactation sources: Drugs and Lactation Database (LactMed) [Internet]. Bethesda (MD): National Library of Medicine (US); 2006-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK501922/1. Yarur A, Kane SV. Update on pregnancy and breastfeeding in the era of biologics. Dig Liver Dis. 2013;45:787-94. PMID: 23474350
2. Matro R, Martin CF, Wolf D et al. Exposure concentrations of infants breastfed by women receiving biologic therapies for inflammatory bowel diseases and effects of breastfeeding on infections and development. Gastroenterology. 2018;155:696-704. PMID: 29857090
3. Mahadevan U , Robinson C, Bernasko N et al. Inflammatory bowel disease in pregnancy clinical care pathway: A report from the American Gastroenterological Association IBD Parenthood Project Working Group. Gastroenterology. 2019;156:1508-24. PMID: 30658060
4. Baker TE, Cooper SD, Kessler L, Hale TW. Transfer of natalizumab into breast milk in a mother with multiple sclerosis. J Hum Lact. 2015;31:233-6. PMID: 25586712
5. Hainke U, Sehr T, Eisele JC et al. Natalizumab: Passage into breast milk and neonatal blood. Mult Scler. 2015;23:690. Abstract EP1324 DOI: doi:10.1177/1352458515602642
6. Proschmann U, Thomas K, Thiel S et al. Natalizumab during pregnancy and lactation. Mult Scler. 2018;24:1627-34. PMID: 2885768
Disclaimer: This material is provided for educational purposes only and is not intended for medical advice, diagnosis, or treatment. Consult your healthcare provider with any questions.
