Still learning, Bosulif advice

Hi Manda,

If I remember from when I was on Bosutinib in 2018, the Patient Information Leaflet at the time advised to take the tablets with breakfast. I've always taken the various TKI's I have been on in the evening after a meal since I find the side effects are more manageable. I mentioned this to my Consultant at the time, and they were happy for me to take it in the evening. It is important, however, that you take it with food and around the same time each day.

I don't want to alarm you about Bosutinib, but make sure you have regular Liver Function Tests and ask what the results are. I had to come off Bosutinib after 4 months since my AST/ALT (liver enzymes) levels rose too high. On the plus side I did reach MMR on Bosutinib and I never experienced the dreaded diarrhoea (in fact only Dasatinib caused this problem for me).

I hope Bosutinib works well for you.

Take care,

James

Hi Manda,

How much Bosulif you take?

Thanks
Zoran

Hi Manda,

Yes, I started Bosulif mid December 2024. Here is a couple of important notes I learned about it:

1. It takes time till it starts working and till you see measurable results. In my case it was probably 4 weeks, so do not rush with dose escalation. As you are on 400 mg I think there is no need to increase it.

I started 1st week 100 mg, 2nd week 200, 3rd week 300 and since I haven't had any issues and I was already 2 months on only 1/2 dose Asciminib and my wbc strated rising, I increased to 400 mg. 3 weeks later I started experiencing adverse effects, first mild and then severe.

2. It takes 7-10 days to stop working, so if you see something strange in your test results, don't wait too long to react (stop or reduce the dose). In the 7th week I suffered thrombocytopenia, anemia and a massive tooth infection. I actually stopped taking it when the tooth infection started worsening, the swelling started growing. The day I stopped taking it, my platelets were 43 and a week later they were 25. So it seems, certainly depending on the person's metabolism, it accumulates in the bloodstream and it takes unusually long time to clear out. I say unusually long time as I was on Imatinib, Dasatinib, Nilotinib and Asciminib and I have never seen this nor I read about it in Pfizer documentation or any research paper on Bosutinib.

3. I don't think it makes any difference when you take it and they recommend to take it with food. I tried it without food and it makes you a bit nauseous, but way less than Imatinib. What I found is that plasma concentration increases significantly with food:

200 mg with food is like 450 mg without food.
400 mg with food is like 650 mg without food

https://pubmed.ncbi.nlm.nih.gov/21691746/
https://www.cancercareontario.ca/en/drugformulary/drugs/monograph/44371
https://sepia2.unil.ch/pharmacology/parameters/areaunderthecurve/

So if you turn out to be over sensitive like myself you may need to reduce the dose, especially if you take it with food. I find it very strange that such info was not shared by Pfizer considering the severity of potential adverse effects, how fast they may develop and how long it takes for the medication to be removed from the system.

4. You should also monitor for the signs of liver problems "alanine aminotransferase" and "aspartate aminotransferase" as these seem to go up in many cases. For me these have been unaffected so far.
https://labeling.pfizer.com/showlabeling.aspx?id=884#S5.3

I'm now off and waiting for my cells to recover, then I will restart at 100 mg and then maybe 200 mg and see how it goes.

Good luck
Zoran