Ado-Trastuzumab Emtansine and Breastfeeding

Summary of use during lactation

No information is available on the clinical use of ado-trastuzumab during breastfeeding. Because trastuzumab is a large protein molecule with a molecular weight of 145,531 Da, the amount in milk is likely to be 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] However, ado-trastuzumab emtansine also contains DM1, which is a small-molecule toxin that might enter milk and be absorbed by the infant. Because of the potential for serious adverse reactions in the breastfed infant, the manufacturer recommends avoiding breastfeeding during and for 7 months following ado-trastuzumab emtansine therapy.

Drug levels in milk and infant serum

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

Effects in breastfed infants

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

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
2. Anderson PO. Monoclonal antibodies during breastfeeding. Breastfeed Med 2021;16:591-3.33956488 PubMed