Is Pegvaliase safe while breastfeeding?
Here is what LactMed, the Drugs and Lactation Database published by the U.S. National Institute of Child Health and Human Development (NICHD), reports about Pegvaliase. The text below is quoted from that source — it is not our own verdict.
Summary of use during breastfeeding
No information is available on the use of pegvaliase during breastfeeding, but amounts in milk appear to be trivial. Absorption of the drug by the infant from breastmilk is unlikely because it is a polypeptide that is probably destroyed in the infant's gastrointestinal tract. Professional guidelines support the use of pegvaliase during breastfeeding.[1] Polyethylene glycol is not excreted into breastmilk.[2] Pegvaliase may decrease the phenylalanine content of breastmilk. The manufacturer recommends monitoring blood phenylalanine concentrations in breastfeeding women treated with pegvaliase.
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: Drugs and Lactation Database (LactMed), National Institute of Child Health and Human Development (NICHD), via NCBI Bookshelf, record “Pegvaliase” (LM1388). LactMed on NCBI Bookshelf. LactMed is a registered trademark of the U.S. Department of Health and Human Services.
Educational summary of an authoritative source — not medical advice. Never start, stop, or change a medicine while breastfeeding without confirming with your doctor.