Is Pegvaliase safe while breastfeeding?

Here is what NIH LactMed, the U.S. National Library of Medicine's authority on medicines and breastfeeding, reports about Pegvaliase. This is a summary of that source — not our own verdict.

Effects on the breastfed infant

A woman with phenylketonuria reinstituted pegvaliase therapy when her infant was 2 weeks old. She began with a dose of 10 mg per week on day 12 postpartum, then increased to 70 mg per week on day 27 postpartum, 140 mg per week on day 46 postpartum. The dosage was reduced to 80 mg weekly on day 55 postpartum, then increased to 110 mg weekly on day 97 postpartum, where it remained. She breastfed her infant twice daily and the infant gained weight normally and met developmental milestones. Mental development was average at 14 months of age.[ 4 ] A woman with phenylketonuria had an unplanned pregnancy while taking pegvaliase. Postpartum, she received a dose of 120 mg per week while exclusively breastfeeding her infant. At 5 months of age, her infant was developing normally with no concerns.[ 5 ]

Effects on milk supply

Relevant published information was not found as of the revision date.

Levels in milk

Maternal Levels. A woman with phenylketonuria stopped her pegvaliase during pregnancy and for 7 months while breastfeeding her infant. After weaning, she restarted pegvaliase and pumped breastmilk samples for analysis while taking a dose of 20 mg daily. The activity of phenylalanine ammonia lyase (the active portion of pegvaliase) was equal to background levels found in blank breastmilk and TRIS buffer solution.[ 3 ] In her second pregnancy, pegvaliase was measured in breastmilk at four time points when she was receiving 80, 110 and 140 mg of pegvaliase weekly. No sample had any detectable pegvaliase activity.[ 4 ] Infant Levels. Relevant published information was not found as of the revision date.

Source: NIH LactMed (National Library of Medicine).

Educational summary of an authoritative source — not medical advice. Never start, stop, or change a medicine while breastfeeding without confirming with your doctor.