I saw my haematologist yesterday and was told my BCR ABL result had risen from 0.05 to 6+ in 3 months. I’m a bit concerned as he is changing my TKI to BOSUTINIB. This will be my third TKI as I’ve already tried Imatanib and Nilotinib, having had bad side effects with these two. I’m concerned as I may have side effects on this one.
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Lack of response on Nilotinib
If I understood your post correctly and you were at 0.05% (MMR) and have gone to >6.0% then it is a good idea to switch as there may be a mutation that another TKI would do better with. I do not understand how you were switched to Nilotinib from Imatinib if you had not responded to Imatinib since they work similary (Nilotinib naturally more potent).
I would request a re-test to confirm since you were/possibly are in MMR as lab errors, although rare, do occur. If confirmed I would insist on mutation testing before any switch is made. In other words without a mutation test you could be moving to Bosutinib while harboring a mutation that Sprycel or Ponatinib would be more effective with. Just my thoughts but I'm sure others will provide reassurance and insight. Hope you get the appropriate TKI working soon. Take care.
Thank you for your reply. I was having extremely bad bone pain on imatanib and not really responding. When I went on to Nilotinib, my response was very quick, although I was having bad side effects. I have had two test results where my BCR ABL has increased. From 0.05, then to 0.5 and finally to 6. I’m seeing my nurse in a week to discuss things. I don’t really understand why my results keep rising.
You’ve probably already been asked this question by your doc and presume your adherence to the strict 12 hour gap between meds on Nilotinib. And also missing no doses? Also are you on 600mg or 800mg. 600 is the standard but 800 is for those who are imatinib resistant.
I hope this gets sorted for you. A stressful time I am sure.
I am also on Tasigna. My own experience is the effectiveness of this TKI is largely dependent on how well it is absorbed. When I changed fasting time from two hours to at least three hours. My PCR started to drop (before that it stayed high). If I have digestive problem during the period, then my PCR will go up again. I think digestive issue causes body absorbing only a fraction of the medicine, hence the drug will not work to its full potential. It does not necessarily mean that you are resistant to Tasigna.