The amount of ipilimumab in breastmilk appears to be very low, but it may increase with subsequent doses during a treatment cycle. It is likely to be partially destroyed in the infant's gastrointestinal tract and absorption by the infant is probably minimal.[1] Until more data become available, ipilimumab should be used with caution during breastfeeding, especially while nursing a newborn or preterm infant. The manufacturer recommends that breastfeeding be discontinued during ipilimumab therapy and for 3 months after the last dose.