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Stay course or switch TKI


Thank you for this website. It has been very helpful for me. I was diagnosed in Chronic phase last November with a BCR of 96% and began treatment Nov 17 on Imatinib. At my 3 month check I was at 15%. We did not switch but checked again at 4 1/2 months and I was at 5.1%. Now at the 6 month check I am at 3%.

Aside from a rash, the side effects have subsided and I am tolerating Imatinib well. But this response seems slower than the standard. I see my Oncologist tomorrow and will see what she thinks. Initially we debated between Imatinib and Dasatinib, but went with Imatinib.

Since I didn't get to under 1% by the 6 month mark would you consider a switch or would you stay the current course?

Hi Mike,

There's no concensus on this really. Some studies suggest that reaching 10% (on the International Scale) by 3 months is desirable, and correlated with good outcomes. Others are of the opinion that slow and steady can win the race, so as long as your PCR is dropping over time then they might advise to stick with it.

Going by the European Leukaemia Net recommendations, you are in "warning" (I have been there several times myself) and the "by the book" suggestion changing a TKI at 6 months is recommended if you are above 10%. On the same criteria, it would suggest that after 1 year you shoudl be under 1% and if not, then that is considered "failure" and a good time to switch.

Personally, I would not get overly worried about exact figures. If you were 0.9% at your next result would you stay with imatinib? If you were 1.1% at your next result, how would you feel. 1.5%?

Would you be comfortable staying with imatinib, if it works well for you in terms of side effects, for another 6 months to see if you can get to below 1%. Switching to dasatinib may really help your PCR but it could bring side effects which are difficult to manage.

I switched from imatinib to dasatinib and it did make a rapid difference to my PCR. But I switched for side effect reasons. I'm very glad I did it - but it was for different reasons to yours.



Hello and welcome, Mike

Personally, if you are doing OK on imatinib - and it sounds as if you are - I'd stick with it.  I've been on it nearly 8 years now and have had no problems apart for the side effects (which do lessen over time).  It isn't a race to get down to zero!  If things change along the line, there are other TKIs which may do the job faster but have different side effects.  At least with imatinib you don't have to fast for hours every day.  Other people on this site may have different experiences and different views, you just have to find what works best for you.

Good luck with whatever you decide.


Thanks for the comments. After meeting with my oncologist we are staying on Imatinib for now. She did say a case could be made to switch. We will check again in 6 weeks and again at my 9 month mark. If I am not below 1% by the 9 month check then she will change to Dasatinib.

She felt for now I am moving in right direction but would have switched me and support a change if I am too anxious about the slower pace on Imatinib. I trust her as she specializes only in CML and has for 20 years. She said she felt I do not risk my long term prognosis by waiting until the 9 month mark though of course she can't guarantee I won't develop a resistance or mutation. The biggest downside she raised was that at my current pace she felt I would not be able to look at trying to stop taking the medicine until around year 5, but if I wanted to speed that possibility up we could switch now to a second generation.

I felt that I am tolerating Imatinib really well with no major side effects. Therefore I am going with slow but steady path for now. We can always change at 9 months if needed.

Sounds like a sensible plan. Best of luck!