No information is available on the clinical use of elotuzumab during breastfeeding. Because elotuzumab is a large protein molecule with a molecular weight of 148,100 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, elotuzumab is administered with dexamethasone and lenalidomide, two drugs that have no information on use in nursing mothers. The manufacturer recommends that women receiving elotuzumab should not breastfeed.