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18months into Glivec (Imatinib) - PCR >0.1%

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Hi All,

I’ve been on Glivec 400mg for the past 18 months after discovering intolerance to Tasigna during initial diagnosis of CML.

My BCR-ABL results went from 1.4% —> 0.4% and after another 6 months —> 0.3%.

By 18months I was supposed to achieve <0.1% at least. Based on this information, my doctor has offered two options:

1) continue another 6 months on Glivec 400mg and check again if PCR has further significant reduction (risk: PCR may go up)

2) increase dosage of glivec to 600mg.

what would be your recommendations based on experience here? Should I be very concerned? 

Hi,

How are you doing with side effects on Glivec/Imatinib? I plateaued at about 0.3% for a few months and then got to less than 0.1% in a big jump. I issed the guideline but I didn't know - the guidelines had not been written back then!

As the trend is still down my suggestion would be stay where you are for another 3 months and if there's not a good reduction change something. If the imatinib side effects are not too bad just now an increase in dose might be the first thing to try. Remember the guidelines are for optimum response - having got as low as you are already it is very unlikely that you won't at some stage get below 0.1% - it is just about finding the right way for you. 

Tasigna and Glivec work the same way in terms of how the drug binds to the active site in CML leading to cell death. Tasigna binds more tightly and is generally more effective than Glivec because of this.

I would suggest you consider switching to low dose dasatnib (sprycel) at 50 mg. Your PCR is already quite low and changing drug type (i.e. from Glivec/Tasigna to sprycel) will attack your remaining CML more thoroughly. On 50 mg you may very well see your PCR plummet. Dasatinib attacks CML at a higher cell level and binds to a different active site than Glivec/Tasigna. This has the effect of cascading CML failure down the system.

I would also suggest should sprycel work for you (and it most likely will) and your PCR does drop, to cut dose further to 40 mg or even 20 mg. Sprycel is one of those drugs that is "threshold". When it works, it works very well. More dose is not better - and in fact can lead to unpleasant side effects and less effectiveness. Your doctor should understand how sprycel works and why lower starting dose for those who already have deep response is wise. If he doesn't suggest he read up. I would not start sprycel at 100 mg. If he wants to do that, you might as well stay with Tasigna.

Hi, 

im fairly tolerating well in terms of side effects on Glivec (just typically daily loose stools and the standard normal tiredness). Otherwise I’m quite ok. And yes, I’ve generally turned super fair (like an albino)...hahaha...

i have given my doctor the decision to continue with glivec 400mg till my next PCR in Oct’19. If readings still remain the same then only will opt to increase dosage to 600mg.

our Asian country does not offer Dasatinib for now and access to that medicine is limited, unfortunately. I can’t tolerate well with Tasigna as I almost had a total body shutdown (collapse) when I first started treatment with this medicine.

thanks for the response and will pray for the best☺️