No information is available on the clinical use of ramucirumab during breastfeeding. Because ramucirumab is a large protein molecule with a molecular weight of about 147,000 Da, the amount in milk is likely to be very low. It is also likely to be partially destroyed in the infant's gastrointestinal tract and absorption by the infant is probably minimal. Until more data become available, ramucirumab should be used with caution during breastfeeding, especially while nursing a newborn or preterm infant. The manufacturer recommends that breastfeeding be discontinued during ramucirumab therapy and for 2 months after the last dose.