Pegasys

[pmeyer]

I am a perinatologist. My patient is taking Pegasys (Peginterferon alfa-2a) for essential thrombocytosis. She is very interested in breastfeeding. I recall seeing a thread in the old forum discussing limited passage of alpha interferon into breastmilk due to molecular size. Do you think this apply to Pegasys?
Thanks,
Paul Meyer MD

[admin]

Dr. Meyer:

We are just publishing some new data on beta interferon which confirms that virtually none of it ever reaches the milk compartment. I estimate that the level in milk averaged about <250 units/mL as compared to a maternal dose of 32 million units. Even then, it is unlikely to be orally absorbed in the GI tract of the infant.

Thus, these milk levels are not much at all. I think it would be about the same for alpha interferon as well. I have an old paper where we found almost no alpha interferon in milk as well. Remember, interferons are large molecular weight products (24,000 daltons), and they are largely sequestered by the T cells in the plasma and tissues. Virtually no interferon is found in the plasma compartment, hence little enters milk.

I would not be concerned about the use of this product in a breastfeeding woman.

Tom Hale PH.D.

[pmeyer]

Paul Meyer MD

Thank you Dr. Hale. That is most helpful.
Paul Meyer MD

Dr. Meyer:

We are just publishing some new data on beta interferon which confirms that virtually none of it ever reaches the milk compartment. I estimate that the level in milk averaged about <250 units/mL as compared to a maternal dose of 32 million units. Even then, it is unlikely to be orally absorbed in the GI tract of the infant.

Thus, these milk levels are not much at all. I think it would be about the same for alpha interferon as well. I have an old paper where we found almost no alpha interferon in milk as well. Remember, interferons are large molecular weight products (24,000 daltons), and they are largely sequestered by the T cells in the plasma and tissues. Virtually no interferon is found in the plasma compartment, hence little enters milk.

I would not be concerned about the use of this product in a breastfeeding woman.

Tom Hale PH.D.

[lauriebeck]

Dr. Hale - We have a NICU mom with a 27 weeker, 2 day old and mother has been taking 350 mcg of Besremi Interferon q 2 weeks with last dose April 16, 2024. Unable to find if this medication is compatible with breastfeeding, especially with a premie. She did receive the medication during her pregnancy. Mom is being treated for Polycythemia. Laurie Beck, RN, MSN, IBCLC Driscoll Children's Hospital in Corpus Christi, Texas.

Thank you for the information.

[nicholec]

Hi Laurie,

The molecular weight of Besremi Interferon is 60,000 Da. Since mom was dosed during pregnancy, baby does have this drug in their system and does have some degree of immunosuppression. Anything that would happen in breastfeeding will be negligible compared to the transfer they received in utero. This is unlikely to get in milk, but it it did, there would be detrimental effects, so close infant monitoring would be necessary. The pediatric team should already be aware and monitoring for side effects of drug exposure in this baby.

Nichole Campbell, MSN, APRN, NP-C
InfantRisk Center