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3 month PCR Log Reduction

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Is there a target for log reduction after 3 months of treatment?

I have seen some literature that states 1.0 or below. I'm not sure that that's typical for 1st gen drugs, or if 2nd gen drugs should expect a quicker response.

I am taking 100mg dasatinib, and my 3 month PCR was a 1.6 log reduction.

I assume this is a fair result, just looking for some reassurance.

My hematologist seems to not focus so much on early diagnosis PCR results, and said my "target" should be a 3 log reduction at 12 months.

Hi Taper11, I think there are milestones that people can use as reference when making treatment decisions, however these milestones are generalized and might not reflect exactly your case. If you browse different CML forum you'll find many patients whose BCR-ABL didn't fit the optimal criteria, but went on to have good results on the long run. Here's my BCR-ABL history, you might find it useful to compare:

* 2014: 1.03
* 2015: 0.063
* 2016: 0.07
* 2017: 0.089  |  0.0132
* 2018; 0.02  |  0.0091
* 2019: 0.0  |  0.0  |  0.0  |  0.0073
* 2020: 0.00 
* 2021: 0.011 | 0.00 | 0.00

In the beginning of my treatment back in 2014 my goal/hope was to get very low BRC-ABL results.That was my success metric. Today, 8 years later, after reading and researching a lot I came to the conclusion that the metric of success should include dancing like this guy over here: https://www.youtube.com/watch?v=uS8fYjT9bfc&list=RDuS8fYjT9bfc&start_radio=1

PS: I still pray for good results in every PCR test.

I've seen plenty of posts with the rollercoaster ride like you've had. I understand it's common and shouldn't be dwelled upon.

I'm still pretty early down the road, having only 1 PCR test. But at this point a 1.62 log reduction would fall into the optimal response category I suppose.

I'll hope for good results in the future, but when it comes to celebrating victories I'm not much of a dancer 😁

Hi,

Generally the 3 month goal is 10%, which is a 1-log drop from 100%. Even if we are not 100% at diagnosis (could be higher, could be lower) we “pretend” we are so results are standardised.

10% at 3 months is considered “optimal” which means even if you don’t meet this there is not an immediate cause for concern.

These treatment guidelines are not differentiated between different TKIs, even though some work faster than others. So it’s often an individual judgement with your doctor.

But if you have a 1.6 log reduction that would mean about a 2.3% result (this of maths off the top of my head) which is significantly below 10%. The next “optimal” goal would be 1% by 6 months, which is a 2-log drop. And as your doctor says, 0.1% (or 3-log drop) is optimal at 12 months.

It seems you are doing great!

David.

Thanks for the explanation regarding the different treatment options.

Nice work on figuring that from the top of your head. I had to get out my calculator 😁.

I get the feeling from my hematologist that he thinks percentages are blasphemy, but it's easy enough for me to figure out assuming you started at 100%