No information is available on the clinical use of necitumumab during breastfeeding. Because necitumumab is a large protein molecule with a molecular weight of 145,000 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] Waiting for at least 2 weeks postpartum to resume therapy may minimize transfer to the infant.[3] However, the manufacturer recommends that women receiving necitumumab should not breastfeed during therapy or for 3 months following the final dose.