Loncastuximab Tesirine use while Breastfeeding

Summary of Use during Lactation

No information is available on the clinical use of loncastuximab tesirine during breastfeeding. Because loncastuximab is a large protein molecule with a molecular weight of about 151,000 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, loncastuximab is conjugated with SG3249, a small-molecule alkylating agent 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 that women not breastfeed during treatment and for 3 months after the final dose.

Drug Levels

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 [CrossRef]

2.

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

Substance Name

Loncastuximab Tesirine

CAS Registry Number

1879918-31-6

Drug Class

Breast Feeding

Lactation

Milk, Human

Antibodies, Monoclonal, Humanized

Antineoplastic Agents