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.