No information is available on the clinical use of dinutuximab during breastfeeding. Because dinutuximab is a large protein molecule with a molecular weight of about 150,000 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] Until more data become available, dinutuximab should be used with caution during breastfeeding, especially while nursing a newborn or preterm infant. The manufacturer recommends that breastfeeding be discontinued during dinutuximab therapy.