Agree with the previous comments. There is risk here to both the mother and the infant. It is essential to get control of the CML ASAP. I know breast feeding is felt to be important at many levels, but even if the risk to the baby was non-existent, the possibility of disease progression to something not controllable, does exist. I believe in talking bluntly. If Mom wants the best chance to see the infant grow up, then she must get her CML under control. The infant will survive formula. Mom needs ideal therapy.

As a pediatrican I fully agree with Tim Hughes's statements. The key idea of breast feeding is -among others- "on demand" feeding. That makes any considerations of drug (and it's metabolites with unknown toxicity for a baby) concentration in the blood and the milk based on kinetic halving times rather meaningless. Although not an ideal situation, millions of babies have been raised without mother's milk by commercial baby food without signs of failure to thrive.
Meinolf Suttorp

I agree with Tim. I would avoid breastfeeding in this case and I would resume nilotinib as soon as possible.

We have always said that breast feeding was not possible in this setting – unless she wants to take the risk of a longer period without effective therapy. Maybe if her control was excellent on interferon (MMR) this could be contemplated. I wouldn’t recommend breast feeding while taking nilotinib. I guess we could do drug levels on the milk but there are several metabolites that might not be measured but could be toxic to a baby. I would strongly discourage this idea.

When you state that she has disease progression in the first trimester you mean she had cytogenetic or haematological relapse, not transformation to AP/BC. Just clarifying that for the forum readers.

Hi
I have a 40yo first pregnancy now 32/40. IVF while in CMR on nilotinib ceased prior to conception, disease progression during first trimester requiring interferon - only just managing with side effects (but hopefully in the home stretch). I'm hoping i can talk her out of breastfeeding as we plan to resume nilotinib once delivered for disease control but she is particularly interested in any data on levels of any TKI (preferably second gen as previous poor tolerance and suboptimal response imatinib) in breastmilk and whether this can be predicted to minimise exposure to the newborn with careful discarding/timing of feeding. She is prepared to test serial breastmilk samples on nilotinib (and discard until we have resolved risk) if anyone in Oz able to do this (?Tim).
Thanks - Melita